Listeriosis

J Immunol, 1991 Jan 15, 146(2), 756 - 61
Tumor necrosis factor-independent IL-6 production during murine listeriosis; Havell EA et al.; We report that TNF, IL-6, and IFN-alpha/beta are produced by mice during either sublethal or lethal Listeria monocytogenes infections . The quantities of these cytokines in infected spleens increase and decrease in concordance with bacterial numbers in these organs . While all of these cytokines were present in Listeria-infected spleens, only IL-6 and IFN-alpha/beta were found in the peripheral circulation . Inasmuch as TNF has been reported to be responsible for the production of IL-6 in vivo following the inoculation of a lethal dose of the Gram-negative bacterium, Escherichia coli (Fong et al., 1989 . J . Exp . Med . 170: 1627), experiments were undertaken to determine whether IL-6 production elicited by the Gram-positive bacterium, L . monocytogenes, was also TNF-dependent . It was found that the passive immunization of mice with neutralizing antibodies specific for TNF shortly before i.v . injection of a lethal or sublethal Listeria inoculum resulted in the complete neutralization of endogenously produced TNF, and in the progressive multiplication of bacteria in infected organs . It was also found that the anti-TNF IgG treatment resulted in a progressive increase in the amounts of Listeria-induced IL-6 present in spleen and blood, until the death of the host . These findings indicate that Listeria-induced IL-6 production in mice occurs primarily through a TNF-independent pathway, and correlates directly with the severity of the infection.

FEMS Microbiol Lett, 1991 Jan 15, 61(2-3), 181 - 6
Antibodies to listeriolysin O reflect the acquired resistance to Listeria monocytogenes in experimentally infected goats; Miettinen A et al.; We induced experimental listeriosis in goats by two sequential oral inoculations of Listeria monocytogenes serovar 1/2a at 8 months' interval . Immunoblot analysis with the goat sera demonstrated listeriolysin O (LLO) as the principal protein antigen of L . monocytogenes . Pre-existing antibodies to LLO were, depending on their initial level, associated with either mild clinical symptoms of short duration or the total absence of clinical symptoms . Similarly, the presence and development of such antibodies corresponded with the disappearance pattern of L . monocytogenes from the gastrointestinal tract . These findings suggest that an association exists between antibodies to LLO and acquired resistance to Listeria infections.

Med J Aust, 1991 Jan 7, 154(1), 59 - 60
Listeria monocytogenes peritonitis associated with CAPD; Hart KA et al.; Listeria monocytogenes peritonitis developed in a 67-year-old man on continuous ambulatory peritoneal dialysis following a catered luncheon . Alcoholic liver disease was a predisposing factor . L . monocytogenes multiplies at 4 degrees C . It is often present in imported soft cheese, less often in chicken and other refrigerated food . Listeria peritonitis has not been previously reported in Australia.

Int J Immunopharmacol, 1991, 13(2-3), 197 - 204
Factors involved in the depression of hepatic mixed function oxidase during infections with Listeria monocytogenes; Azri S et al.; A number of infections are capable of depressing the capacity of the liver to metabolize drugs . We have studied a number of factors which could be involved in the depression of cytochrome P-450 and related drug biotransformation enzymes during infections with Listeria monocytogenes . During the course of the infection, drug metabolism and heme content of hepatic microsomes were depressed but heme oxygenase was elevated . A free radical scavenger alpha-tocopherol did not prevent the loss and xanthine oxidase activities did not correlate with the time course of the loss . Infections in susceptible (balb/c) mice produced a larger loss in drug metabolism than in resistant (C57BL/6) mice, and an avirulent strain of the bacteria was without effect . A preparation of hemolysin isolated from Listeria monocytogenes produced a dose-dependent loss of cytochrome P-450 in isolated hepatocytes . These experiments indicate that the loss of drug metabolism during Listeria infections is most likely due to hemolysin released by the bacteria.

Gynecol Obstet Invest, 1991, 31(3), 179 - 81
Maternal-fetal listeriosis: 2 case reports; Svare J et al.; Two cases of maternal-fetal infection with Listeria monocytogenes are reported . Both women were admitted with influenza-like symptoms and preterm labor at 32 and 34 weeks of gestation, respectively . The infants were delivered within a few days of onset of maternal symptoms . One infant was seriously ill with meningitis and subsequently developed hydrocephalus . The other infant suffered from septicemia, but had no sequelae . It is recommended always to consider the diagnosis listeriosis in pregnant women with fever of unknown origin and preterm labor.

Ann Med Interne (Paris), 1991, 142(2), 95 - 8
{Neuromeningeal Listeria infections in adults . Clinical, biological and therapeutic aspects . Apropos of 36 cases}; Lazanas M et al.; In this retrospective study, 36 cases of Listeria monocytogenes meningitis were reviewed . A bacteriological confirmation was obtained for every patient either by lombar puncture or blood culture . The clinical picture and the composition of the cerebrospinal fluid were polymorphous . Most patients were previously in good health, while 10 of them (28%) had a predisposing factor: pregnancy, gastrectomy, diabetes mellitus, alcoholism or immunosuppression . The outcome was favorable in 23 patients (64%); 8 patients were cured with sequelae (22%); 5 patients died (14%) . Death occurred in patients suffering from concomitant underlying disease, such as coronary insufficiency (n = 1) or immunosuppression (n = 2), or in the case of delayed diagnosis and treatment (n = 2).

Comp Immunol Microbiol Infect Dis, 1991, 14(1), 1 - 7
Latest news on listeriosis; Courtieu AL; Emphasis is given essentially to the presentation of recent data in terms of our total knowledge of Listeria and human and animal listeriosis . This disease of extremely varied origin can be studied in terms of two groups of subjects: females in gestation and all other categories of individuals . There was initially only a single species of Listeria, but at least five are known today, only two of which are pathogenic . Their pathogenic power is related essentially to the presence of listerolysin O, although this is not the only factor involved . Identification of Listeria is easy and can be completed with that of its serovar and lysovar . Epidemiological studies have shown that the great majority of listeriosis are anademic . The contamination of receptive subjects is due to certain forms of food . In the absence of efficient vaccination, disease prevention must be obtained by eliminating Listeria from food.

Rev Infect Dis, 1991 Jan-Feb, 13(1), 115 - 9
Listeriosis in patients infected with human immunodeficiency virus; Berenguer J et al.; Although resistance to Listeria monocytogenes infection requires intact T cell-mediated immunity, only 20 patients with human immunodeficiency virus (HIV) infection and listeriosis (including one patient described herein) have been reported to date . Listeriosis developed before AIDS in five cases . Syndromes included meningitis in nine cases, bacteremia in nine, brain abscess in one, and endocarditis in one . Eighteen patients were treated with ampicillin, penicillin, or amoxicillin with or without aminoglycosides . Clinical and microbiologic responses were obtained in one patient with bacteremia treated with vancomycin and in one patient with meningitis treated with trimethoprim-sulfamethoxazole . Three of the nine patients with meningitis died, as did the patient with brain abscess . All nine patients with bacteremia and the patient with endocarditis survived . No case of relapse was documented . L . monocytogenes, although uncommon, should be considered in the differential diagnosis of febrile illness, meningitis, and brain abscess in patients with HIV infection.

Infection, 1991 Jan-Feb, 19(1), 36 - 40
Listeria brainstem encephalitis: two own cases and literature review; Kohler J et al.; We analysed two of our own and 21 patients described in the literature with listeria brainstem encephalitis . The disease was characterised by a prodromal state with fever, nausea and headache followed by severe brainstem dysfunction with multiple cranial nerve palsies, ataxia, respiratory insufficiency and coma . The diagnosis was established by isolation of Listeria monocytogenes from CSF and/or serum . Serological tests are without diagnostic evidence . Cerebrospinal fluid examination may not initially point to a bacterial infection . Computed tomography and magnetic resonance imaging technique might supply evidence of brainstem involvement and contribute to an early diagnosis . There is a high percentage of lethal outcome without early antibiotic therapy.

J Infect, 1991 Jan, 22(1), 53 - 7
Maternal listeriosis in pregnancy without fetal or neonatal infection; MacGowan AP et al.; Maternal infection with Listeria monocytogenes without fetal or neonatal involvement is relatively rare . Eleven cases arising in England and Wales between 1967 and 1988 are presented.

Am J Obstet Gynecol, 1991 Jan, 164(1 Pt 1), 57 - 8
Successful antepartum treatment of listeriosis; Kalstone C; A pregnant patient had a flulike illness at 27 weeks . Listeria monocytogenes infection was diagnosed by blood cultures . Electronic monitoring suggested the fetus was stressed . Use of tocolytics inhibited uterine contractions while the mother was treated with intravenous ampicillin . Four days later when labor began because of chorioamnionitis, the infant was delivered in good condition.

Immunopharmacol Immunotoxicol, 1991, 13(3), 395 - 411
Enhanced macrophage anti-microbial activity following dimethylnitrosamine exposure in vivo is related to augmented production of reactive oxygen metabolites; Edwards CK 3rd et al.; Previous results demonstrated that mice exposed in vivo to DMN were more resistant to both bacterial and tumor challenges . Furthermore, macrophages (M phi) isolated from these animals demonstrated increased functional properties . As reactive oxygen intermediates (ROI) represent a key mechanism of anti-microbial action, it was important to determine whether ROI levels in M phi were related to augmented anti-microbial action in animals exposed to DMN in vivo . Peritoneal exudate M phi elicited with either thioglycollate (TG), Con A or C . parvum (CP) were examined for the production of ROIs . TG-M phi, Con A-M phi and CP-M phi obtained from animals exposed to DMN showed increased superoxide anion (O2-) production in vitro following stimulation with either phorbol myristate acetate (PMA) or opsonized zymosan (Op-zym) when compared to vehicle M phi . ROI production by bone marrow-derived macrophages (BMDM) produced by either GM-CSF or CSF-1 was also determined . BMDM from DMN-exposed animals obtained using either growth factor, had increased ROI production at 3, 5, 7 and 9 d of culture compared to vehicle BMDM . There was no shift in the kinetics of ROI production during differentiation of these BMDM . Analysis of extracellular anti-listericidal activity of TG- and CA-elicited M phi demonstrated that only TG-M phi obtained from DMN-exposed animals had enhanced killing capacity . There were no differences in intracellular anti-microbial activity in TG- and CA-elicited M phi obtained from either vehicle or DMN-exposed animals . TG-elicited M phi from either vehicle or DMN-exposed animals were examined for anti-microbial activity and H2O2 production following in vitro exposure to PMA . M phi from both vehicle and DMN treatment groups had enhanced killing and H2O2 production following PMA treatment, while PMA-stimulated TG-M phi from DMN-exposed animals demonstrated significantly higher levels of H2O2 production and cell killing as compared to all other treatment groups . These results suggest that previously observed increases in anti-microbial action by M phi from DMN-exposed animals are due in-part to enhanced ROI production.

Life Sci, 1991, 49(16), PL107 - 12
Effects of amphetamine on T-cell immune response in mice; Freire-Garabal M et al.; Mice chronically injected with amphetamine (0.4 mg/kg/day) showed a reduction in thymus and spleen cellularity, and in peripheral T lymphocyte population . The blastogenic response of spleen lymphoid cells was assessed and amphetamine was found to inhibit T-cell proliferation . Amphetamine also reduced the capacity of mice to the development and passive transfer of immunity to Listeria monocytogenes.

Mikrobiyol Bul, 1991 Jan, 25(1), 15 - 20
{Listeria monocytogenes contamination of raw milk from different regions of Anatolia and pasteurized milk sold in Ankara}; Sharif A et al.; In this study 77 raw milk samples from different regions of Anatolia and 22 pasteurized milk samples sold in Ankara were investigated for isolation of L . monocytogenes . For the isolation of Listeria, each sample was plated directly onto McBride's Listeria Agar (MLA) and on the other hand four processing methods (2 long cold enrichment and 2 shortened warm enrichment procedures, followed by plating) were used . Listeria colonies on MLA medium were examined by the Henry Method of oblique lighting . Suspected colonies from MLA were subjected to biochemical tests to confirm identity . 14 samples (18.2%) of all examined samples raw milk were determined to be positive for Listeria monocytogenes . We found that Tryptose Phosphate Broth enrichment procedure gave significantly better results than others and allows L . monocytogenes isolation from milk most frequently . All of tested pasteurized milk samples were negative for L . monocytogenes.

Infection, 1991, 19 Suppl 4, S234 - 8
Effect of various antibiotics on Listeria monocytogenes multiplying in L 929 cells; Nichterlein T et al.; Various antibiotics were evaluated as to their effect on Listeria monocytogenes SLCC 4013 multiplying within L 929 mouse fibroblast cells . Antibiotics were employed in concentrations above the MIC value . However, there was no measurable effect of some drugs on intracellular listeriae (azlocillin, mezlocillin, cephalothin, ciprofloxacin, chloramphenicol) . With other drugs an inhibition of intracellular growth was observed (penicillin, ampicillin, rifampicin, rifapentine, erythromycin, doxycycline, co-trimoxazole, coumermycin) . Notably, with none of the antibiotics a complete eradication of the listeriae was achieved . There is a good correlation of these results with animal experiments . Therefore, the cell culture system might be useful for the screening of new antibiotics.

Infection, 1991, 19 Suppl 4, S195 - 7
Studies on the pathogenicity of Listeria monocytogenes; Goebel W et al.; The characterization of mutants of Listeria monocytogenes with reduced virulence properties is described . Reduction in the amount of the extracellular protein p60 (encoded by the ipa gene) leads to cell filaments with impaired invasiveness . Mutants which cannot synthesize listeriolysin are still invasive but unable to survive within phagocytic cells . One type of listeriolysin-negative mutants is defective in the synthesis of a positive regulatory element PrfA which coordinately regulates the listeriolysin gene (lisA) together with several other genes, including those for a phosphatidylinositol-specific phospholipase and a metalloprotease.

Appl Environ Microbiol, 1991 Jan, 57(1), 289 - 94
Evaluation of hybridization characteristics of a cloned pRF106 probe for Listeria monocytogenes detection and development of a nonisotopic colony hybridization assay; Kim CM et al.; An internal fragment (pRF106 fragment, ca . 500 bp) of a gene (msp) coding for a 60-kDa protein of Listeria monocytogenes serotype 1/2a was used to develop a screening method to discriminate between L . monocytogenes and avirulent Listeria spp . on primary isolation plates . The L . monocytogenes-derived probe fragment of pRF106 hybridized to a 13-kb fragment of L . monocytogenes and a 3-kb fragment of one cheese isolate strain of Listeria seeligeri under stringent hybridization conditions (mean thermal denaturation temperature {Tm}-5 degrees C) . The probe also hybridized to a 6-kb fragment of Listeria innocua, Listeria ivanovii, and L . seeligeri under less stringent hybridization conditions (Tm-17 degrees C) . The pRF106 fragment was labeled with digoxigenin-11-dUTP and used to develop a colony hybridization assay . Colonies from lithium chloride-phenylethanol-moxalactam agar were blotted onto nylon membranes . The cells were pretreated with microwaves before lysis with sodium hydroxide . DNA-DNA hybridization and posthybridization washing were done at high stringency (Tm-7 degrees C) . The nonisotopic colony hybridization procedure was specific for L . monocytogenes when evaluated against pure cultures of L . monocytogenes and other Listeria species, excluding the cheese isolate of L . seeligeri . Also, it was specific for L . monocytogenes when evaluated with Listeria-negative food enrichment cultures that were inoculated in the laboratory with Listeria species.

J Dairy Sci, 1991 Jan, 74(1), 81 - 6
Survival of Listeria monocytogenes in a food colorant derived from red beets; el-Gazzar FE et al.; Three commercial lots of the red beet colorant were inoculated to contain circa 10(3) to 10(7) Listeria monocytogenes strains California, V7, or Scott A per milliliter and stored for 56 d at 7 degrees C . McBride listeria agar was used to determine numbers of survivors . Selected colonies thought to be L . monocytogenes were confirmed biochemically . When necessary, samples were tested by cold enrichment (up to 8 weeks) . Samples of colorant initially containing 10(3) to 10(4) strain California/ml were always free of the pathogen after 56 d, and sometimes after 42 d . Samples with high initial numbers (10(5) to 10(6)/ml) were not free of the pathogen after 8 wk at 7 degrees C . Strains V7 and Scott A, regardless of size of initial population, always survived beyond 56 d . Before inoculation, all test samples of colorant were free of L . monocytogenes (direct plating or cold enrichment).

Eur J Epidemiol, 1991 Jan, 7(1), 77 - 82
Ribosomal DNA fingerprinting of Listeria monocytogenes using a digoxigenin-labeled DNA probe; Graves LM et al.; A nonisotopic ribosomal DNA fingerprinting technique was developed for the characterization of Listeria monocytogenes . Plasmid pKK3535 (a pBR322-derived plasmid containing rrnB ribosomal RNA operon of Escherichia coli) was labeled with digoxigenin-11-dUTP by random priming and used to probe EcoRI fragments of L . monocytogenes chromosomal DNA on nylon filters . The method was successfully applied to the characterization of two sets of patient and food isolates of L . monocytogenes.

Immunol Lett, 1991 Jan, 27(1), 45 - 8
Effect of two feeding formulas on immune responses and mortality in mice challenged with Listeria monocytogenes; Chandra RK et al.; Cell-mediated immunity and natural killer cells play an important role against facultative intracellular organisms . The effect of two commercially available tube feeding formulas used for patients with acute or chronic debilitating and life-threatening illnesses was studied in mice challenged with Listeria monocytogenes . C57BL/6 X DBA/2 F1 hybrid mice were given ad libitum access to one of two formulas or to chow . Sixty mice in each of the feeding groups were challenged with 4.8 X 10(3) organisms intraperitoneally . Mortality was significantly less in animals fed Impact, a formula enriched with arginine, RNA and selected fatty acids . This was associated with reduced number of viable organisms in the spleen on day 7 after challenge . There was no difference in the spleen/body weight index between the different groups . Delayed cutaneous hypersensitivity was slightly higher in the Impact group but this was not statistically significant . Natural killer cell activity was significantly higher in the Impact group compared with the other two feeding regimens . These observations suggest that selective manipulation of the composition of tube feeding formulas may have a significant impact on immune responses and on morbidity and mortality following infectious challenge.

J Appl Bacteriol, 1991 Jan, 70(1), 40 - 6
Effects of gaseous environment and temperature on the storage behaviour of Listeria monocytogenes on chicken breast meat; Hart CD et al.; Portions of skinless chicken breast meat (pH 5.8) were inoculated with a strain of Listeria monocytogenes and stored at 1, 6 or 15 degrees C in (1) aerobic conditions; (2) 30% CO2 + air; (3) 30% CO2 + N2; and (4) 100% CO2 . When samples were held at 1 degree C the organism failed to grow under any of the test conditions, despite marked differences between treatments in spoilage rate and ultimate microflora . At 6 degrees C counts of L . monocytogenes increased ca 10-fold in aerobic conditions before spoilage of the meat, but only when the inoculum culture was incubated at 1 degree C rather than 37 degrees C . In CO2 atmospheres growth of L . monocytogenes was inhibited on meat held at 6 degrees C, especially under 100% CO2 . By contrast, storage at 15 degrees C led to spoilage of the meat within 2 d, in all gaseous environments, and listeria levels increased up to 100-fold . Differences in the behaviour of L . monocytogenes on poultry and red meats are discussed.

Hokkaido Igaku Zasshi, 1991 Jan, 66(1), 41 - 8
{Enhancement of host defence against infection with Listeria monocytogenes in newborn mice by various recombinant cytokines}; Chen Y; Neonatal mice within 24 h of birth were highly susceptible to infection of Listeria monocytogenes . The 50% lethal dose of bacterial cells for neonates and adult mice was 6.3 X 10(1) CFU and 3.2 x 10(6) CFU, respectively . A single intraperitoneal injection of recombinant murine interferon-gamma (rMuIFN-gamma) protected neonates from the simultaneous challenge with a lethal dose of L . monocytogenes . The protection of rMuIFN-gamma was consistently observed in neonates at doses more than 4 X 10(2) IU (0.1 micrograms protein) per mouse . The bacterial growth in the spleens and livers of neonates treated with rMuIFN-gamma was significantly suppressed in comparison with that in the untreated neonates . Furthermore, survived neonates from the infection with L . monocytogenes showed an acquired resistance against the intravenous injection of lethal dose of L . monocytogenes 4 weeks after the primary infection, and this resistance significantly increased in mice that had been treated with rMuIFN-gamma . In addition to rMuIFN-gamma, recombinant human interleukin-1 beta and recombinant human tumor necrosis factor -alpha were also effective on rescue from the lethal infection with Listeria monocytogenes in neonatal mice, but the effect was seen only in the limited doses . On the other hand, recombinant murine IFN-beta and recombinant human IL-2 were not effective at all . These results suggest that rMuIFN-gamma rather than other cytokines might endow neonatal mice with the enhanced antilisterial resistance involving macrophages and T lymphocytes.

Int J Syst Bacteriol, 1991 Jan, 41(1), 59 - 64
Taxonomy of the genus Listeria by using multilocus enzyme electrophoresis; Boerlin P et al.; Seventy-three strains of the seven recognized Listeria species were studied by performing a multilocus enzyme electrophoresis analysis of 18 enzyme loci . The mean number of alleles per locus was 9.5 and all of the loci were polymorphic . A total of 56 electrophoretic types were distinguished . Cluster analysis of a matrix of the genetic distances between paired electrophoretic types revealed that there were six principal clusters at the species level (genetic distances between clusters greater than 0.8) . Listeria monocytogenes, Listeria innocua, Listeria welshimeri, Listeria seeligeri, and Listeria ivanovii each corresponded to one of these clusters with no overlap . Our results are in agreement with those of previous DNA hybridization experiments (Rocourt et al., Curr . Microbiol . 7:383-388, 1982) . Listeria grayi and Listeria murrayi electrophoretic types formed a unique cluster, thus reinforcing the suggestion of Wilkinson and Jones (J . Gen . Microbiol . 98:399-421, 1977) that these two species should be considered two biovars of a single species.

J Med Microbiol, 1991 Jan, 34(1), 13 - 8
Pathogenicity of Listeria monocytogenes isolates in immunocompromised mice in relation to listeriolysin production; Tabouret M et al.; The virulence of 74 Listeria monocytogenes isolates from clinical cases and food products and of 11 isolates of other Listeria species was tested in mice immunocompromised with carrageenan . Isolates of species other than L . monocytogenes were not lethal to such mice . All 29 clinical isolates of L . monocytogenes (serotypes 1/2a, 1/2b, 4b) and 33 of 42 isolates of various serotypes isolated mainly from dairy products killed all test mice (100% lethality) at an inoculum of 10(4) cfu/mouse . All lethal strains of L . monocytogenes were haemolytic and possessed the 58-Kda band specific for listeriolysin O as demonstrated by SDS-PAGE immunoblotting . The nine avirulent strains of L . monocytogenes had detectable haemolytic activity, but in six of them this activity was significantly weaker than in virulent strains and the 58-Kda band was not detected . The other three avirulent strains were highly haemolytic and possessed the 58-Kda band, which suggests that other factor(s) could be involved in the virulence of L . monocytogenes.

An Otorrinolaringol Ibero Am, 1991, 18(4), 403 - 8
{Adenopathy caused by Listeria monocytogenes}; Sans Saez A et al.; Human infection by Listeria Monocytogenes has been considered a rare disease in adults, usually associated to immunosuppressed patients . Meningitis is the main clinical manifestation . Sepsis, endocarditis, peritonitis and circumscribed abscesses are occasionally found.

Rev Belge Med Dent, 1991, 46(2), 51 - 8
{Chemical control of plaque: comparative review}; Marechal M; Plaque control can be achieved by mechanical means . Since plaque removal can be laborious and difficult, chemical agents became important adjuncts to traditional oral hygiene procedures . Chlorhexidine is one of the synthetic antiseptics that has a unique antiplaque effect and 0.2% chlorhexidine can achieve a practically complete plaque control . It has one negative effect namely an extrinsic brown-yellow staining . Listerine has proven its ability to reduce plaque and gingivitis in a moderate way . Hexetidine has a greater antiplaque effect in combination with zinc and can be compared with a 0.1% chlorhexidine . Povidone-iodine can not be used to keep plaque at low levels . Sanguinarine can reduce plaque accumulation when the toothpaste and mouthrinse are used together . H2O2 is an antiplaque agent but has some negative effects such as ulcerations.. . One can conclude that the use of a chemical agent cannot replace a good mechanical plaque control but is rather an adjunct to oral hygiene under certain conditions.

Infection, 1991, 19 Suppl 4, S229 - 33
Therapeutic activities of antibiotics in listeriosis; Hof H; In vitro practically all common antibiotics except cephalosporins are active against nearly all natural isolates of Listeria monocytogenes; the therapeutic efficacy of antibiotic treatment is, however, rather limited, since up to 30% listeriosis patients will succumb to this infection . At least one reason for this low in vivo efficiency is the intracellular habitat of L . monocytogenes . In animal experiments ampicillin or amoxicillin, respectively, are still the most active drugs . In addition, rifampicin also has pronounced protective activity . Coumermycin, which unfortunately cannot be given to humans, is the most reliable drug in animals.

Arch Immunol Ther Exp (Warsz), 1991, 39(5-6), 529 - 36
Effects of gonadotrophin on resistance to Listeria monocytogenes infection in mice; Rozalska B et al.; It was demonstrated that exogenous GH suppressed the resistance to L . monocytogenes infection in Listeria resistant C57Bl/6 and susceptible A/J mice . However, different parameters of the immunological reaction to Listeria were affected by GH treatment in these mouse strains . In C57Bl/6 mice GH decreased accumulation of macrophages at the inflammatory site . On the contrary, a depression of anti-listerial activity of the phagocytes and a reduction of DTH reaction to Listeria antigen was demonstrated in GH treated A/J mice.

Zentralbl Bakteriol, 1991 Jan, 274(4), 527 - 32
Immunostimulatory effect of Rothia dentocariosa in mice; Bednar M et al.; In mice killed Rothia dentocariosa cells in doses of about 1.5 mg dry weight activated anti-infection immunity to Listeria antigens and anti-tumour immunity to the ascitic form of mouse sarcoma S-180 . Their probable target site is the macrophage . The Rothia-activated macrophages in human gingiva may take part in the pathogenesis of periodontal disease . Three models were employed to verify the immunostimulating properties of preventively administered Rothia dentocariosa bacterin-1) a spleen macrophage migration test, using mice immunized with Listeria innocua, with the soluble listeria Ei antigen as the antigenic signal, 2) determination of the increase in the Listeria monocytogenes LD50 for mice and 3) the prolongation of survival of mice carrying the S-180 tumour . In all three cases, the administration of Rothia bacterin stimulated the immune response to the later administration of other antigens . Furthermore, in the macrophage migration inhibition test, the chemotaxis of non-immune mouse macrophages was found to be stimulated . This gives evidence of the fact that Rothia bacterin has an activating effect on these macrophages.

Eur J Cancer, 1991, 27(4), 435 - 7
Listeria monocytogenes brain abscesses in a girl with acute lymphoblastic leukaemia after late central nervous system relapse; Viscoli C et al.; A case of Listeria monocytogenes bacteraemia and meningitis with intracerebral abscesses in a girl with acute lymphoblastic leukaemia in relapse is reported . The clinical features included subacute onset with fever and marked irritability followed by seizures, meningism and confusion . The pathogen was isolated from blood and cerebrospinal fluid . Computerised tomography of the brain showed two intracerebral parenchymal localisations, in the left frontal lobe and in the right occipital lobe, respectively . The patient survived this severe infection without neurological sequelae . 2 months later she underwent allogeneic bone marrow transplantation without major complications . This case report should alert pediatric oncologists about the possible occurrence of severe intracerebral listerial infections in the immunocompromised child and suggests that this infection can be treated successfully and should not necessarily preclude continuation of antineoplastic treatments.

Folia Microbiol (Praha), 1991, 36(2), 183 - 91
Informative value of a mouse model of Klebsiella pneumoniae infection used as a host-resistance assay; Malina J et al.; To obtain a host-resistance assay (HRA) for quantitative evaluation of immunostimulatory effects of various substances, an experimental model of K . pneumoniae inhalatory infection was elaborated . The highly virulent bacterial strain (inhalation LD50 = 400 CFU), applied via the natural route into the respiratory tract elicits an acute infectious process possessing characteristic dynamics . Although the intensity of clearance in the bronchoalveolar lavage after challenge or the mean survival time can be used in individual cases for quantitative resistance determination, the inhalation LD50 values yielded the most standard results . Systemic immunization with the corpuscular K . pneumoniae vaccine provided a high protection expressed by increasing the inhalation LD50 by two orders of magnitude . The antibodies formed, detectable by the ELISA test, are specific for capsular polysaccharide . The type-specific immunity was also found in the protection test . The nonspecific stimulatory effect of the peptidopolysaccharide complex isolated from Listeria monocytogenes (EiF) was manifested at the level of one LD50 only while with higher infectious doses it was absent . However, the adjuvant activity of EiF was significant . The HRA can distinguish and quantitatively determine both nonspecific and specific stimulatory effects of immunomodulatory substances.

Przegl Epidemiol, 1991, 45(3), 231 - 5
{A case of Listeria meningoencephalitis with a fatal result}; Wawrzynowicz-Syczewska M et al.; A fatal case of severe meningoencephalitis caused by Listeria monocytogenes in a compromised alcoholic has been described . Unconsciousness, full meningeal symptoms with slight lateralisation of signs, seizures, respiratory failure within three days before death have been observed.

Funct Dev Morphol, 1991, 1(4), 37 - 46
Insulin immunization of guinea-pigs: biochemical, immunohistochemical and morphometric findings with and without the use of adjuvant; Mullerova M et al.; Changes in the blood glucose level, glucose (GTT) and insulin (ITT) tolerance tests, anti-insulin antibody production and morphological changes in pancreatic tissues (in particular the islets of Langerhans) were studied . After immunization by insulin (I) or insulin combined with an adjuvant (IE, IF), the blood glucose level rose, changes were observed in the GTT and ITT and after four successive immunizations the immunofluorescence technique also demonstrated anti-insulin antibodies . None of the above changes was observed in the controls, to which saline containing complete Freund adjuvant (SF) or Listeria factor (SE) was administered . On the other hand, the morphological picture changed in both the experimental (IE, IF) and control (SE, SF) groups, in which (round) cell infiltration of the fine connective tissue of the omentum and even of mesentery, with nonspecific granuloma formation was observed, while huge multinuclear cells appeared in the SF group . The changes were more frequent in the IE and IF groups . The volume density of the pancreatic endocrine tissue increased significantly only in the experimental groups (I, IE, IF), in which the increase was accompanied, to a varying degrees, by degranulation of the B-cells . The results of analysis of volume density changes of A-, B-, and D-cell populations were correlated with the blood glucose levels . The morphological findings may explain why the originally insignificant production of anti-insulin antibodies and the increase in the blood glucose level observed in guinea pigs after the repeated administration of chromatographically purified insulin are significantly enhanced by the administration of adjuvants together with the immunizing agent . Complete Freund adjuvant was found to be more effective than the Ei Listeria factor.

Acta Microbiol Hung, 1991, 38(1), 3 - 6
Heat resistance of Listeria monocytogenes in naturally infected and inoculated cow's milk; Kovincic I et al.; A two phase slug flow tubular heat exchanger was used for the thermal inactivation of Listeria monocytogenes in natural infected milk from seven cows . L . monocytogenes serotype 4b inoculated UHT sterilized milk was monitored in a parallel study . The two milks were heated at 71.1 degrees C for holding times of 2, 4, 10, 15, 20 and 30 s . Milk was assayed for survivors immediately after heat treatment and weekly thereafter for 4 weeks during storage at 4 degrees C . No survivors were detected in the naturally infected milk at any of the holding times . Survivors were found at 2 and 4 s in the inoculated UHT milk with initial titres of 8 x 10(2) to 7.1 x 10(3) c.f.u./ml, only after storage at 4 degrees C for 28 days . No survivors were detected for 10 through 30 s holding times.

Acta Microbiol Hung, 1991, 38(2), 155 - 60
Meditation of the taxonomy of Listeria; Ralovich B; Listeria monocytogenes was exactly identified and named in 1924 . Since then the name and taxonomic position of listeriae have been changed several times . The last classification was performed on the basis of genetic studies and of some biological properties (haemolytic character, virulence and acid production from sugars) . On the basis of the taxonomic validity of these characters, the Listeria genus is proposed to be classified into three species: L . monocytogenes (four subspecies), L . ivanovii and L . grayi (two subspecies).

Acta Microbiol Hung, 1991, 38(2), 141 - 5
Model examination of selective media for isolation of Listeria strains; Domjan Kovacs H et al.; During the Tenth International Symposium on Listeriosis (Pecs, Hungary, 1988) the Working Party on Culture Media of IUMS-ICFMH suggested comparative examination of nine enrichment broths and nine solid selective media . On the basis of this proposal the following media were studied: LiCl-phenylethanol-moxalactam agar (LPM), polymyxin-acriflavine-LiCl-ceftazidime-aesculin-mannitol agar (PALCAM) No . 1 (home made) and No . 2 (Merck), acriflavine-ceftazidime agar (AC), Oxford agar, tripaflavine-nalidixic acid serum agar (TNSA) and Forray's agar . The study was performed as described in "Testing methods for use in quality assurance of culture media" . Oxford agar proved to be the best medium . LPM, AC and Forray's agars were somewhat more inhibitory than Oxford medium . In productivity TNSA and PALCAM media were weakest but the latter one was more selective . When 43 sausage samples were enriched in UVM broths and subcultured on the above mentioned media the number of positive samples was the same on Oxford, LPM, AC and TNSA agars but it was lower on PALCAM agar No . 1 . When 103 milk samples were subcultured on TNSA and PALCAM agar No . 2, the number of positive samples was the same.

Zentralbl Pathol, 1991, 137(5), 385 - 94
{Pathology of the placenta . VII, Inflammation of the placenta}; Emmrich P; A general account of routes of infection is followed by reference to localisations of placental infection . The most common routes of infection are transmembrane, transdecidual, haematogenico-maternal, and haematogenico-foetal . Intra-uterine infections with placental involvement may be caused by several types of pathogens, with particular reference being made to listeriosis, tuberculosis, and lues, while virus infections may be associated with rubella and cytomegaly and protozoonosis with toxoplasmosis . Unambiguous morphological traces are left in the placenta merely by few of these "specific" infections . A possible pathogen, therefore, can be rarely concluded from the type of inflammatory placental involvement . Reference is also made to "villitis of unknown aetiology", an aetiologically obscure, probably haematogenico-maternal infection of the placenta . Introduction of this term to histological routine diagnosis is recommended . This account of placental inflammation is completed by explanations on relationships between inflammation and impaired maturation of the placenta as well as between inflammation and intervillous fibrin deposition or chronic disorders of intervillous circulation.

Boll Ist Sieroter Milan, 1991-92, 70(1-2), 495 - 8
{Recent data on the spread of Listeria spp . in the province of Ferrara}; Bucci G et al.; The results of the investigations of Listeria held from 1985 to 1989 in samples of foods, surface waters and stools are reported . On the whole 98 strains of Listeria were isolated, 38 of which were L . monocytogenes . The first isolation of L . grayi from human stools is pointed out.

Free Radic Res Commun, 1991, 12-13 Pt 1, 371 - 7
Cloning and expression in Escherichia coli of a gene encoding superoxide dismutase from Listeria ivanovii; Haas A et al.; A chromosomal DNA fragment from the gram-positive bacterium Listeria ivanovii (ATCC 19119) encoding a superoxide dismutase (SOD) gene has been cloned in Escherichia coli QC779 (sodAsodB) using the plasmid vector pTZ19R . The DNA fragment inserted into the plasmid showed high structural instability in E . coli QC779 (recA+), but turned out to be a stable 1.95 kbp DNA fragment when transformed into E . coli DH5 alpha (recA-) . The gene is expressed in both of these E . coli strains at high levels . Preliminary studies showed that the activity of the recombinant SOD within E . coli DH5 alpha was up to 13-times the combined activity of both E . coli SODs . The recombinant SOD forms active hybrid SODs with both E . coli SODs in vivo.

Med Arh, 1991, 45(3-4), 103 - 4
{Asymptomatic and manifest forms of listeriosis in neonates}; Milisic J; Pointed out has been a danger of listeria monocytogenes infections, which is most frequently transplacentally transmitted from the mother to the baby . In such cases, it results in early, septic forms with disseminated abscesses and granulomas in many organs . A case with a positive outcome has been described . Infection incited during delivery or soon after it results in late, meningitic form of listeriosis, which is characterized with a high mortality outcome . Such a case that resulted in death has also been described . Three children infected by listeria remained asymptomatic . Pointed out has been the inevitability of antibiotic treatment of such children, too, to prevent listeria from developing septic meningitic form . Imperative to prevent nosocomial listeria infections in obstetric wards, which is a reality, are strict measures of hygiene.

J Clin Oncol, 1990 Dec, 8(12), 2014 - 8
Mechlorethamine, vincristine, and procarbazine chemotherapy for recurrent high-grade glioma in adults: a phase II study; Coyle T et al.; We undertook a phase II study of combination chemotherapy with mechlorethamine (nitrogen mustard) 6 mg/m2 intravenously day 1 and day 8, vincristine 2 mg intravenously day 1 and day 8, and procarbazine 100 mg/m2 orally days 1 through 14 (MOP) in adults with recurrent high-grade glioma . There were 31 patients entered and 27 patients assessable for response . The median age was 49 years old . All patients had prior maximal radiotherapy, and eight had previous chemotherapy . Responses were determined based on clinical and computed tomographic (CT) scan/magnetic resonance imaging (MRI) criteria . The response rate (partial response {PR} plus objective qualitative response {OQR} plus complete response {CR}) was 52% with one CR . The response rate was higher in patients with anaplastic astrocytoma as compared with glioblastoma multiforme (P less than .05) . The median duration of response was 42 weeks . Median survival for all assessable patients was 30 weeks, and for responders, it was 60 weeks . Response was correlated with ability to decrease dexamethasone doses and improved performance status . Toxicity was mainly hematologic with leukopenia being common . There was one treatment-related death from listeria meningitis, and two patients developed Pneumocystis carinii pneumonia . There were three episodes of neutropenic fever . We conclude that MOP is active and merits further investigation in adult high-grade glioma.

J Immunol, 1990 Dec 1, 145(11), 3540 - 6
Presentation of Listeria monocytogenes to CD8+ T cells requires secretion of hemolysin and intracellular bacterial growth; Brunt LM et al.; Cell-mediated immunity to Listeria monocytogenes (LM) involves both CD4+ and CD8+ T cell responses . An important virulence factor in the pathogenesis of infection and development of protective immunity to LM is secretion of the sulfhydryl-activated hemolysin (Hly), listeriolysin . Listeria secretion of Hly allows LM to escape the endosomal compartment and enter the cytosol of the cell where intracellular growth can occur . We developed a system using bone marrow macrophages cultured in CSF-1 or IFN-gamma for comparing the response of CD4+ or CD8+ T cells to heat-killed, live Hly-, and live Hly+ LM . Macrophages grown in CSF were permissive for intracellular growth of Hly+ but not Hly- LM . CD8+ T cells recognized Hly+ LM but not HK or Hly- LM pulsed macrophages . However, CD4+ T cells recognized all three Listeria preparations fed to IFN-gamma-treated macrophages . These results suggest that both heat-killed LM and live LM efficiently enter the exogenous pathway for class II Ag processing and presentation . In contrast, only Hly+ LM activates the class I pathway, probably as a result of Hly+ bacterial replication within the cytosolic compartment.

J Dairy Sci, 1990 Dec, 73(12), 3428 - 32
Efficiency of sanitizing agents for destroying Listeria monocytogenes on contaminated surfaces; Mafu AA et al.; In an effort to control the potential hazard of dairy product contamination by contact with processing surfaces, the efficiency of four commercial sanitizing agents was evaluated using the AOAC use-dilution method for their bactericidal activity at 4 and 20 degrees C against Listeria monocytogenes strain Scott-A attached on four types of surfaces (stainless steel, glass, polypropylene, and rubber) . Our results indicate that all sanitizers tested were more efficient against L . monocytogenes attached to nonporous surfaces than to porous surfaces . After 10 min of contact time, the limit concentration of disinfectants was at least 5 to 10 times higher for sanitizing rubber than stainless steel or glass surfaces . Concentrations of each sanitizer needed to be higher at sanitation at 4 degrees C than at 20 degrees C to destroy L . monocytogenes attached to stainless steel, glass and rubber when surface contamination was achieved at 4 or 20 degrees C.

J Dairy Sci, 1990 Dec, 73(12), 3351 - 6
Fate of Listeria monocytogenes during the manufacture and ripening of Parmesan cheese; Yousef AE et al.; Parmesan cheese was made from a mixture of pasteurized whole and skim milk that was inoculated to contain ca . 10(4) to 10(5) cells of Listeria monocytogenes/ml . Curd was cooked at 51 degrees C (124 degrees F) for ca . 45 min . During cheese making, maximum numbers of L . monocytogenes appeared just before cooking; at this point, the increase over initial numbers was a .61 to 1.0 order of magnitude . During cooking of curd, the average decrease in numbers of L . monocytogenes was a .22 order of magnitude . During cheese ripening, numbers of L . monocytogenes decreased almost linearly and faster than reported for other hard cheeses . Listeria monocytogenes strain California died faster than did strain V7 . Listeria monocytogenes were not detected in cheese after 2 to 16 wk of ripening, depending on the strain of the pathogen and the lot of cheese . Parmesan cheese made in this study was not a favorable medium for survival of L . monocytogenes.

Appl Environ Microbiol, 1990 Dec, 56(12), 3874 - 7
Cloning of the listeriolysin O gene and development of specific gene probes for Listeria monocytogenes; Datta AR et al.; A clone containing 3.1 kb of Listeria DNA was selected from a gene library of Listeria monocytogenes Scott A strain . The Escherichia coli clone produced hemolysin on sheep blood agar and in sonicated extracts but very little in the culture supernatant . This 3.1-kb DNA fragment and a 650-bp HindIII fragment located within the listeriolysin gene were used as probes in a colony hybridization assay . Both probes were specific for L . monocytogenes and did not hybridize with any other Listeria strains at high stringency . Two synthetic probes, one from the 650-bp HindIII fragment and one from the carboxy-terminal region of the protein, were also specific for L . monocytogenes.

Int J Food Microbiol, 1990 Dec, 11(3-4), 259 - 69
Fate of Listeria monocytogenes in orally dosed chicks; Husu JR et al.; The fate of Listeria monocytogenes in chicks perorally dosed with these bacteria at 2 days of age was determined by bacterial enumeration, immunoperoxidase staining and histological examination of the liver, muscle and gastrointestinal tract . Results revealed listerial egress from the digestive tract and elimination of the organism from the body in most of the chicks within 9 days post-inoculation . L . monocytogenes was isolated from the caecum of only one of 10 chicks examined at 4 weeks post-inoculation . Results indicate that chickens are not likely to be common reservoirs of L . monocytogenes . Intestinal carriage of L . monocytogenes by poultry may frequently be transient, resulting from ingestion of Listeria-contaminated feed and soil.

Int J Food Microbiol, 1990 Dec, 11(3-4), 205 - 14
Growth of Listeria monocytogenes Scott A, serotype 4 and competitive spoilage organisms in raw chicken packaged under modified atmospheres and in air; Wimpfheimer L et al.; The development of Listeria monocytogenes Scott A, serotype 4 and aerobic plate counts on minced raw chicken were determined independently at 4, 10 and 27 degrees C . Samples were packaged in flexible film under two modified atmospheres (one containing oxygen and one containing no oxygen) or air . The anaerobic modified atmosphere (75:25, CO2:N2) resulted in the failure of both the aerobic plate counts and L . monocytogenes to grow at all temperatures . Both the L . monocytogenes and aerobic plate counts grew in air at all temperatures . The aerobic modified atmosphere (72.5:22.5:5, CO2:N2:O2), which more closely duplicates commercial practice, inhibited the increase in aerobic plate counts by more than 4 log10 cfu/g compared to air at 4 degrees C . However, the L . monocytogenes was not affected by this atmosphere and increased in numbers by nearly 6 log10 cfu/g at 4 degrees C in 21 days . Regression analysis of the log10 growth and 95% confidence intervals showed that the differences between aerobic plate counts and L . monocytogenes in modified atmosphere were large . The ability of L . monocytogenes to grow in the aerobic modified atmosphere was not affected by level of the L . monocytogenes inoculum nor by the initial level of aerobic plate counts . These data show that modified atmosphere packaging of raw chicken (and probably other meats) can substantially inhibit the aerobic spoilage flora while allowing pathogenic L . monocytogenes to increase.

Immunology, 1990 Dec, 71(4), 560 - 5
Suppression of host resistance against Listeria monocytogenes infection by 15-deoxyspergualin in mice; Nakane A et al.; The effects of 15-deoxyspergualin (DSG), an immunosuppressive agent, on host resistance against Listeria monocytogenes were studied in mice . Administration of DSG in the early phase of infection resulted in fatal listeriosis by preventing acquired anti-listerial resistance, even though the infectious dose was sublethal for the untreated controls . In contrast, DSG treatment started after development of the acquired immunity was ineffective . Endogenous production of interferon-gamma (IFN-gamma) and tumour necrosis factor (TNF) in the bloodstreams induced by the infection was normal in DSG-treated mice . Nevertheless, augmentation of macrophage functions such as expression of major histocompatibility complex (MHC) class II antigens, phagocytic activity and listericidal activity induced by the infection was abrogated by DSG treatment . These results suggest that the inhibitory effect of DSG on anti-listerial resistance might be different from cyclosporine A (CsA).

J Cell Biol, 1990 Dec, 111(6 Pt 2), 2979 - 88
Actin filament nucleation by the bacterial pathogen, Listeria monocytogenes; Tilney LG et al.; Shortly after Listeria is phagocytosed by a macrophage, it dissolves the phagosomal membrane and enters the cytoplasm . 1 h later, actin filaments coat the Listeria and then become rearranged to form a tail with which the Listeria moves to the macrophage surface as a prelude to spreading . If infected macrophages are treated with cytochalasin D, all the actin filaments associated with the Listeria break down leaving a fine, fibrillar material that does not decorate with subfragment 1 of myosin . This material is associated with either the surface of the Listeria (the cloud stage) or one end (the tail stage) . If the cytochalasin-treated infected macrophages are detergent extracted and then incubated in nuclei-free monomeric actin under polymerizing conditions, actin filaments assemble from the fine, fibrillar material, the result being that each Listeria has actin filaments radiating from its surface like the spokes of a wheel (cloud form) or possesses a long tail of actin filaments formed from the fine, fibrillar material located at one end of the Listeria . Evidence that the fine fibrillar material is involved in nucleating actin assembly comes from a Listeria mutant . Although the mutant replicates at a normal rate in macrophages, actin filaments do not form on its surface (cloud stage) or from one end (tail stage), nor does the bacterium spread . Furthermore it does not form the fine fibrillar material . Evidence that the nucleating material is a secretory product of Listeria and not the macrophage comes from experiments using chloramphenicol, which inhibits protein synthesis in Listeria but not in macrophages . If chloramphenicol is applied 1 h after infection, a time before actin filaments are found attached to the Listeria in untreated macrophages, actin filaments never assemble on the Listeria even when fixed 3 h later . Furthermore the fine fibrillar material is absent, although there is a coat of dense granular material.

Infect Immun, 1990 Dec, 58(12), 3988 - 95
Nonhemolytic Listeria monocytogenes mutants that are also noninvasive for mammalian cells in culture: evidence for coordinate regulation of virulence; Kathariou S et al.; We identified nonhemolytic mutants of Listeria monocytogenes that were severely deficient in their ability to invade mammalian nonprofessional phagocytes . These mutants were generated spontaneously or by means of transposon Tn916 mutagenesis . In terms of their extracellular proteins, the noninvasive mutants were deficient not only in the sulfhydryl-activated hemolysin (listeriolysin) but also in an antigenically unrelated extracellular protein with an apparent molecular weight of 32,000 which could induce opacity in egg yolk and is considered to be a phospholipase . Our results suggest the existence of a common genetic control between the expression of listeriolysin and that of other determinants, including a phospholipase and determinants involved in the ability of L . monocytogenes to enter mammalian cells.

Infect Immun, 1990 Dec, 58(12), 3973 - 9
Interleukin-1-induced promotion of T-cell differentiation in mice immunized with killed Listeria monocytogenes; Igarashi K et al.; We studied the effects of administration of recombinant interleukin-1 alpha (rIL-1 alpha) to mice after immunization with killed Listeria monocytogenes cells on the promotion of the functional differentiation of T cells in vivo . Mice immunized with killed L . monocytogenes were unable to express cell-mediated immunity to specific antigen in vivo, as determined by delayed-type hypersensitivity (DTH) and acquired cellular resistance (ACR), and splenic T cells obtained from such mice were unable to respond to rIL-2 and specific antigen and to produce IL-2 after antigenic restimulation in vitro . When rIL-1 alpha was given to mice after immunization with killed bacteria . T cells became capable of responding to rIL-2 and specific antigen in vitro . These functions of T cells were similar to those from mice immunized with viable listeriae . Moreover, using a local passive transfer system, it was found that effector T cells mediating DTH but not ACR to L . monocytogenes were generated in mice treated with rIL-1 alpha after immunization with killed bacteria . These T cells were able to produce macrophage chemotactic factor but not macrophage-activating factor or gamma interferon in vitro in response to stimulation with specific antigen . These results suggest that in vivo administration of rIL-1 alpha facilitates the maturation of antigen-specific T cells mediating DTH and that different effector T cells mediating DTH or ACR are involved in cell-mediated immunity to L . monocytogenes.

Mol Microbiol, 1990 Dec, 4(12), 2167 - 78
Attenuated mutants of the intracellular bacterium Listeria monocytogenes obtained by single amino acid substitutions in listeriolysin O; Michel E et al.; Listeriolysin O (LLO), a major virulence factor of the intracellular bacterium Listeria monocytogenes, shares with other known 'thiol-activated toxins' a conserved undecapeptide, ECTGLAWEWWR, located in the C-terminal region of the protein and containing the unique cysteine of the molecule . Single amino acid substitutions were created in this region to study the role of cysteine and tryptophan residues in the lytic activity of LLO as well as in the virulence of the bacterium . Transformation of a transposon-induced non-haemolytic mutant with plasmids carrying the mutated genes allowed allele exchange and transfer of mutations on to the chromosome by in vivo recombination . The mutant strains secreted a full-length 59 kilodalton LLO . A decrease of 25% in the haemolytic activity in culture supernatants was observed in the case of mutation Cys-484 to Ala and of 80% for mutation Cys-484 to Ser . Mutations Trp-491 and Trp-492 to Ala decreased activity by, respectively, 95% and 99.9% . LLOs produced by the mutants, as the wild type, were active at low pH, inhibited by cholesterol, and able to bind to cell membranes . A close relationship was found between virulence of mutants in the mouse model and haemolytic activity in their culture supernatants . These results demonstrate that the thiol group of Cys-484 is not essential for either haemolytic activity in vitro or virulence in vivo . In contrast, Trp-492 appears to be required for both haemolytic activity and virulence . The finding that the nearly non-haemolytic mutant Trp-492-Ala persisted in the spleen for several days after inoculation indicates that mutagenesis of a virulence determinant can attenuate virulence and provides a novel approach to the development of live vaccine strains.

Fortschr Neurol Psychiatr, 1990 Nov, 58(11), 408 - 22
{Listeriosis of the central nervous system}; Nau R et al.; Listeriosis of the CNS is an inflammatory disease of the central nervous system that occurs mostly sporadically or occasionally as a limited epidemic . The pathogens are generally ingested with the food . Whether or not the infection becomes manifest in an exposed person depends on the number of pathogens ingested, on the virulence of the Listeria strain and on the individual disposition . It appears to be of decisive importance for an infection that the cellular immunodefense mediated by the T cells is disturbed; however, even persons without any previous disease worth mentioning may be affected . The characteristics of the various CNS manifestations are demonstrated via the case histories of 12 own patients (acute meningitis and meningoencephalitis, brain stem encephalitis, brain abscess, meningoencephalitis with infected cerebral infarct, chronic recidivating encephalitis) . Early neurological focal signs and symptoms, combined with CSF findings atypical for bacterial CNS disease, should not be taken lightly and may point to listeriosis even though they are not specific for CNS listeriosis . The decisive criterion is the proof of the pathogen in the blood or CSF or the proof of antibody titre changes in the serum . Recent CSF diagnostic methods such as CSF lactate determination and the identification of IgG-positive B lymphocytes are useful in differentiating between viral and noninflammatory CNS disease; most important for follow-up are repeat CSF examinations . High-dosage ampicillin or amoxycillin treatment combined with gentamycin is the therapy of choice in CNS listeriosis . The bactericidal effect achieved thereby is desirable especially if immunodefense is disturbed . Prognosis of CNS listeriosis depends on the underlying disease in each case . The high mortality even among persons who had been healthy before the infection, is at least in part due to delayed diagnosis.

Immunology, 1990 Nov, 71(3), 377 - 82
Anti-bacterial activity of peritoneal cells from transgenic mice producing high levels of GM-CSF; Tran HT et al.; Two lines of transgenic mice carrying the gene for granulocyte-macrophage colony-stimulating factor (GM-CSF) produce vastly increased numbers of macrophages with abundant foamy cytoplasm resembling classical activated macrophages . Cells from both lines were negative for myeloperoxidase, a bactericidal enzyme found in monocytes as well as neutrophils, but not mature macrophages . Cells from the so called 'male line' produced greatly increased levels of oxygen degradation products in response to phagocytosis, compared with cells from the 'female line' or from normal littermates . The ability of the cells to phagocytose and lyse the intracellular bacterium Listeria monocytogenes was tested in vitro using radiolabelled organisms . Although the cells from transgenic mice were more highly phagocytic than cells from normal littermates, cells from either line were no more efficient than normal at lysing the bacteria they had phagocytosed . Nevertheless, because of the high phagocytic rate, more bacteria were exposed to lysis in the cells of transgenic mice, and the final outcome was a higher rate of bacteriolysis.

Zentralbl Veterinarmed B, 1990 Nov, 37(9), 707 - 11
{The detection of the pathogenicity of Listeria using permanent cell lines as an alternative for animal studies}; Heil G et al.; Culture filtrates of 38 strains of Listeria (L.) monocytogenes and of 4 strains of L . ivanovii were all cytotoxic for the vero cell line . Culture filtrates from 35 strains of L . innocua, 12 strains of L . seeligeri, 5 strains of L . welshimeri and 4 strains of L . grayi showed no cytotoxicity for the continuous cell line vero . The use of continuous cell lines permits to distinguish between pathogenic and non-pathogenic Listeria strains and seems to be a suitable method to replace the mouse pathogenicity test or the fertilized hen's eggs test.

J Clin Microbiol, 1990 Nov, 28(11), 2477 - 81
Detection of the aerolysin gene in Aeromonas hydrophila by the polymerase chain reaction; Pollard DR et al.; Synthetic oligonucleotide primers were used in a polymerase chain reaction (PCR) technique to detect the gene for aerolysin in strains of Aeromonas hydrophila and to screen for identical genes in A . caviae, A . sobria, and A . veronii isolated from patients with diarrheal disease . Primers targeted a 209-bp fragment of the aer gene coding for the beta-hemolysin and detected template DNA only in the PCR using nucleic acid (NA) from hemolytic strains of A . hydrophila which were also cytotoxic to Vero and CHO cells and enterotoxic in suckling-mouse assays . PCR amplification of NA from hemolytic A . sobria or nonhemolytic A . hydrophila and A . caviae strains was consistently negative . Primer specificity was determined in the PCR by using NA extracted from 56 strains of bacteria, including hemolytic Escherichia coli and Listeria monocytogenes as well as several recognized enteric pathogens defined in terms of their toxigenicity . The detection limit for the aerolysin gene by PCR amplification was 1 ng of total NA . The PCR clearly identified aerolysin-producing strains of A . hydrophila and may have application as a species-specific virulence test because other hemolytic Aeromonas species tested were negative.

Infect Immun, 1990 Nov, 58(11), 3770 - 8
Isolation of Listeria monocytogenes small-plaque mutants defective for intracellular growth and cell-to-cell spread; Sun AN et al.; To dissect the regulatory and structural requirements for Listeria monocytogenes intracellular growth and cell-to-cell spread, we designed a protocol based on transposon mutagenesis and the isolation of mutants which form small plaques in monolayers of mouse L2 cell fibroblasts . Two different transposable elements were used to generate libraries of insertion mutants: Tn916 and a derivative of Tn917-lac, Tn917-LTV3 . Ten classes of mutants were isolated and evaluated for growth and cell-to-cell spread in J774 mouse macrophagelike cells, Henle 407 human epithelial cells, and mouse bone marrow-derived macrophages . Mutants were also evaluated for secretion of hemolysin and phospholipase (assayed by egg yolk opacity) and association with F-actin in the cytoplasm of cells, using NBD-phallacidin staining . The ten classes of mutants included (i) mutants showing abortive intracellular and extracellular growth; (ii) mutants showing abortive intracellular growth; (iii) rough mutants; (iv) mutants showing greatly reduced hemolysin and phospholipase secretion but showing normal growth in cells and little or no association with F-actin; (v) mutants with mutations mapping to an open reading frame (ORF) adjacent to hlyA and referred to as ORF U, lacking phospholipase activity, and with 50% normal hemolysin activity; (vi) mutants with reduced secretion of both hemolysin and phospholipase; (vii) nonhemolytic mutants with mutations mapping to the structural gene, hlyA; (viii) mutants with 25% normal hemolysin secretion and absolutely no association with F-actin; (ix) mutants with mutations mapping to ORF U, lacking phospholipase activity, and with normal hemolysin activity; and (x) mutants showing a mixed-plaque morphology but normal for all other parameters.

Infect Immun, 1990 Nov, 58(11), 3477 - 86
A nonvirulent mutant of Listeria monocytogenes does not move intracellularly but still induces polymerization of actin; Kuhn M et al.; Listeria monocytogenes has the capacity to penetrate and multiply within professional and nonprofessional phagocytic cells, such as the Caco-2 human enterocytelike cell line . It was shown recently that shortly after listeriae have been phagocytosed, the phagosomal membrane is dissolved, probably by the action of the bacterial cytolysin listeriolysin O . The listeriae, which are then lying obviously free in the cytoplasm, become surrounded by a coat of actin filaments within a few hours . Once formed, this layer of actin filaments is reorganized in an as yet unknown way to form polar tails, which seem to be associated to the generation of listerial movement inside the cytoplasm and in intercellular spread . By using transposon Tn916 mutagenesis, a bank of L . monocytogenes mutants was generated and subsequently screened by the plaque assay system in order to select an intracellular, nonmotile mutant of L . monocytogenes . One such mutant was identified . This mutant, called L . monocytogenes M117 Imt- (for intracellular motility), like the wild type, induced actin polymerization but was not able to rearrange the actin coat to generate movement and as a result remained entrapped within the actin cloud . In a mouse virulence assay, this strain was significantly reduced in virulence . L . monocytogenes M117 is the first example to date of a Listeria mutant which is still hemolytic and invasive but reduced in virulence.

Rev Chil Pediatr, 1990 Nov-Dec, 61(6), 330 - 3
{Early onset neonatal septicemia caused by Listeria monocytogenes}; Sfeir J et al.; Listeria monocytogenes can cause sepsis and meningitis during the neonatal period . Six cases of early onset neonatal sepsis caused by Listeria monocytogenes are reported here . These cases were diagnosed in a private hospital at Santiago, Chile from December 1984 throughout November 1986 . The incidence rate was 1.4 x 1,000 liveborns . Clinical findings included prematurity (6), meconium stained amniotic fluid (6), hepatomegaly (6), splenomegaly (6), maculopapular exanthem (4), anal prolapse (3) and meningitis (1) . Additionally 5 patients developed respiratory distress and 4 required ventilatory support . Overall mortality was 50% (3/6) . All deaths were related to respiratory failure and occurred during the first week of disease . All patients received ampicillin and amikacin early in the course of their infection . Listeriosis of the newborn infant might be preventable by prompt recognition and treatment of maternal infections . Since Listeria infection in pregnancy is usually mild and symptoms and signs are nonspecific, prevention may be difficult . Pregnant women with fever of no clear origin or with an influenza like syndrome should be screened for listeriosis with cultures from blood, vagina and cervix samples.

Bull Tokyo Dent Coll, 1990 Nov, 31(4), 301 - 7
Antibacterial effects of Listerine on oral bacteria; Kato T et al.; To evaluate the efficacy of Listerine, a solution for washing the oral cavity consisting of essential oils (thymol, methanol, eukalyptol) and methyl salicylate, minimum concentrations inhibiting the growth of various microorganisms in the oral cavity and the bactericidal effects on bacteria in the saliva and dental plaque were evaluated in vitro . Listerine inhibited the growth of microorganisms over a very broad range . The minimum concentration inhibiting growth of Listerine was a 4 to 32 fold dilution, 2-4 times as potent as the solution after elimination of active ingredient components, in 38 of 54 bacterial strains, indicating the efficacy of the active ingredient in the inhibition of the growth of microorganisms . Bactericidal action of Listerine against from bacteria isolated from saliva and dental plaque from 5 healthy normal subjects was tested . Listerine exhibited a potent bactericidal effect on bacteria in saliva and dental plaque . Most of the bacteria died after a 30 second exposure to Listerine . According to these results, Listerine appears to be effective as a solution used for cleansing the oral cavity and dentures.

J Appl Bacteriol, 1990 Nov, 69(5), 642 - 7
Listeria monocytogenes contamination of crops grown on soil treated with sewage sludge cake; al-Ghazali MR et al.; Listeria monocytogenes was found in the sewage sludge cake which is commonly used as an agricultural fertilizer in Iraq . Soils treated with this material were contaminated with the organism . Pot and field experiment showed that crops grown on treated soil became contaminated with L . monocytogenes and when alfalfa plant was grown on farmland soil treated with sewage sludge cake, listerias were found on 10% of 50 plants sampled at harvest, but the organism was detected only in low numbers on these crops (less than or equal to 5 cells/g) . This could add to the risk to animals and man.

Appl Environ Microbiol, 1990 Nov, 56(11), 3478 - 81
Detection of Listeria monocytogenes in foods by immunomagnetic separation; Skjerve E et al.; Immunomagnetic separation with immunomagnetic beads was used to isolate strains of Listeria monocytogenes both from pure cultures and from heterogeneous suspensions . The monoclonal antibodies used recognized all six strains of serotype 4 but only one of three strains of serotype 1 . Coating procedure, incubation time, and number of immunomagnetic beads influenced the sensitivity of the isolation method . Less than 1 x 10(2) bacteria per ml in pure cultures and less than 2 x 10(2) bacteria per ml in enriched foods could be detected . The method represents a new approach to extraction and isolation of pathogenic bacteria directly from foods, after resuscitation, or from enrichment broths.

Proc Natl Acad Sci U S A, 1990 Nov, 87(21), 8336 - 40
Identification of a gene that positively regulates expression of listeriolysin, the major virulence factor of listeria monocytogenes; Leimeister-Wachter M et al.; We have isolated, by molecular cloning and genetic complementation of a listeriolysin-negative mutant, a gene required for the expression of this virulence factor in Listeria monocytogenes . The mutant strain SLCC53, which was nonhemolytic and avirulent, harbored a deletion of 450 base pairs located approximately 1500 base pairs upstream of the listeriolysin gene . No transcripts corresponding to the listeriolysin gene were detected in the mutant . DNA sequencing of this region from the hemolytic strain EGD revealed that the region deleted in the mutant would abrogate expression of a 27-kDa polypeptide . Introduction of a recombinant plasmid expressing this 27-kDa polypeptide restored hemolytic activity to the mutant and increased the hemolytic activity of the wild-type L . monocytogenes strain EGD . We have designated the gene encoding the 27-kDa polypeptide prfA, for positive regulatory factor of listeriolysin (lisA) expression . The prfA gene regulates transcription of the lisA gene positively.

Infect Immun, 1990 Nov, 58(11), 3601 - 12
Intracellular hemolysin-producing Listeria monocytogenes strains inhibit macrophage-mediated antigen processing; Cluff CW et al.; We found that virulent hemolysin-producing (Hly+) Listeria monocytogenes strains inhibit antigen processing and presentation when added to macrophages in vitro . A virulent Hly- bacteria caused little or no inhibition . Live Hly+ bacteria inhibited presentation of both heat-killed L . monocytogenes and ovalbumin . Several observations indicate that hemolysin produced by intracellular bacteria was responsible for the inhibition . First, inhibition was observed even when extracellular bacteria were removed after a brief 10-min bacterial uptake period . Second, inhibition was not prevented by the addition of cholesterol, a substance which inactivates soluble hemolysin . Third, only very high concentrations of soluble hemolysin were inhibitory . Under conditions which inhibit antigen presentation (10(5) per well), macrophages retained normal levels of Ia, maintained normal morphology, and were not permeable when assayed by chromium release . The uptake and catabolism of 35S-labeled live bacteria by macrophages were similar for both Hyl+ and Hly- bacteria . Only a small decrease in uptake and catabolism of surface-iodinated heat-killed L . monocytogenes by macrophages pretreated with inhibitory numbers of live Hly+ bacteria was observed . Additionally, macrophages pretreated with live Hly+ bacteria and fixed 1.5 h later were able to effectively present an ovalbumin peptide (amino acids 323 to 339) to the T-cell hybridoma DO11.10 . Hemolysin-producing bacteria inhibited the presentation of antigens that need processing better than they did of antigens that do not require a processing event . Thus, we have demonstrated inhibition of an intracellular antigen processing pathway by hemolysin-producing L . monocytogenes, which may contribute to the virulence of this pathogen.

Infect Immun, 1990 Nov, 58(11), 3582 - 7
Synthesis of species-specific stress proteins by virulent strains of Listeria monocytogenes; Sokolovic Z et al.; Listeriolysin is a virulence factor that appears to be necessary for the intracellular survival of Listeria monocytogenes . As shown in this investigation, listeriolysin is produced in only small amounts by clinical isolates of L . monocytogenes belonging to the serogroup 1/2a, but its synthesis can be induced by heat shock and to a lesser extent by oxidative stress . In addition to about 15 heat shock proteins that appear to be common to L . monocytogenes and Listeria species that are nonpathogenic for humans, at least five heat shock proteins are specifically coinduced with listeriolysin in all L . monocytogenes strains under heat shock conditions but not in the other Listeria species . One type of L . monocytogenes mutant blocked in the expression of listeriolysin failed to synthesize several of these specific heat shock proteins.

FEMS Microbiol Lett, 1990 Nov, 60(3), 249 - 52
Hepatocidal toxicity of Listeria species; Huang JC et al.; A novel rat hepatocidal test, based on morphological changes in monolayer culture and the percentage of lactate dehydrogenase (LDH) released into the medium after exposure to culture filtrates of Listeria spp . was used to determine listerial toxicity and pathogenicity . Primary cultures of rat hepatocytes exposed to brain heart infusion (BHI) culture filtrates from ATCC strains of Listeria monocytogenes and L . ivanovii, released 91-92% and 95% of LDH after 3 h and 18.5 h, respectively . Cultured monolayers changed from normal hepatocytes into nonviable round forms . Brain heart infusion broth and BHI culture filtrates of other Listeria spp . were nontoxic to hepatocytes . The rat hepatocidal test is a quantitative and rapid system for studying listerial toxicity and pathogenicity.

Kansenshogaku Zasshi, 1990 Nov, 64(11), 1468 - 73
{Five cases of listeriosis in the elderly}; Nakajima T et al.; We reported five cases of listeriosis (sepsis and meningitis) in the elderly in our hospital during the last 4 years, where no cases of listeriosis had been found . These 5 cases had diabetes mellitus, lung cancer, chronic respiratory failure, gastric ulcer and aplastic anemia respectively as their underlying diseases . At the onset of listeriosis, 3 cases received corticosteroid and 3 cases received H2-blocker . 2 patients were cured and 3 patients died . Three autopsy cases had meningitis or meningoencephalitis and 2 cases of these autopsy cases had granulomatous changes in these spleens . In serotypes of Listeria monocytogenes (L . monocytogenes), 4 cases were 4b and 1 cases was 1b . All 5 strains were resistant to 3rd generation cephems . Wide uses of 3rd generation cephems and H2-blocker may be one of the reasons for the recent increase of listeriosis . Ingestion of contaminated food is the pathogenetic mechanism for initiating L . monocytogenes infections . And following the change of eating habits and the increase of imported foods, food-born listeriosis may increase . We suppose the increase of L . monocytogenes infections and must give attention to L . monocytogenes infections.

J Toxicol Environ Health, 1990 Nov, 31(3), 203 - 15
Examination of immune parameters and host resistance mechanisms in B6C3F1 mice following adult exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin; House RV et al.; Adult female B6C3F1 mice were given a single ip dose of 0, 01, 1.0, or 10.0 micrograms/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and examined for immune function and host resistance 7-10 d later . Exposure to TCDD resulted in a significant dose-related decrease in induction of both IgM and IgG antibody-forming cells . This suppression was noted for both T-dependent and T-independent antigens . TCDD at a dosage of 10 micrograms/kg was shown to suppress production of antibody to viral hemagglutinin . In contrast, TCDD exposure had no significant effect on natural killer cell function, production of interferon, or various parameters of macrophage function . Assessment of host resistance revealed a significant increase in susceptibility to fatal infection with influenza virus, but no significant alteration in susceptibility to infection with the bacterium Listeria monocytogenes.

Am J Vet Res, 1990 Oct, 51(10), 1513 - 7
Visual-evoked potentials and electroretinograms in ruminants with thiamine-responsive polioencephalomalacia or suspected listeriosis; Strain GM et al.; Electrodiagnostic visual testing (electroretinogram {ERG} and visual-evoked potential {VEP}) was performed on 5 ruminants (3 lambs, 1 kid, and 1 steer) with thiamine-responsive polioencephalomalacia (PEM) and on 2 sheep with listeriosis . The lambs and kid had typical clinical signs of PEM, especially blindness . In these animals, the ERG was normal but the VEP was abnormal . Follow-up recordings in the kid and 1 lamb indicated an improvement in VEP recordings accompanying a gradual return of vision after thiamine treatment . Possible subtle changes in VEP peak latencies could not be assessed because of lack of normative VEP data for sheep and goats . All animals had complete return of vision (owner-assessed) . The steer did not have signs of blindness, and the ERG and VEP were normal . Changes in VEP accompanying permanent PEM blindness are not known . One sheep with suspected listeriosis had lack of menace response and palpebral and corneal reflexes, but had intact vision . The ERG and VEP were normal . The second sheep with suspected listeriosis had intact menace response and vision, but became acutely blind and died; the ERG was normal, but VEP amplitudes were depressed.

J Clin Microbiol, 1990 Oct, 28(10), 2259 - 63
Characterization by DNA restriction endonuclease analysis of Listeria monocytogenes strains related to the Swiss epidemic of listeriosis; Nocera D et al.; Listeria monocytogenes strains responsible for outbreaks of listeriosis were studied by using serotyping and phage typing . An additional approach based on restriction endonuclease analysis (REA) of the chromosomal DNA was used to characterize L . monocytogenes strains collected from various sources during and after a Swiss outbreak of listeriosis (1983 to 1987) . Among the 169 wild-type strains of Listeria spp . that were examined, 161 (95%) belonged to the species L . monocytogenes, of which 109 were of human origin . Ten different REA profiles were obtained from the 120 L . monocytogenes serotype 4b strains tested . All 57 serotype 4b strains that were identified as Swiss epidemic strains by phage typing clustered in two closely related REA profiles . In particular, 10 L . monocytogenes 4b strains isolated from the brand of soft cheese responsible for the outbreak and from its direct environment were indistinguishable from isolates from 40 patients by both phage typing and REA analysis . However, 5 of the 17 non-phage-typeable L . monocytogenes strains and 18 L . monocytogenes strains with a phage type different from those of the Swiss epidemic types showed the same profile . REA enabled the characterization of non-phage-typeable strains and, thus, seems a promising tool for L . monocytogenes typing, especially during epidemiological investigations.

Appl Environ Microbiol, 1990 Oct, 56(10), 3154 - 7
Highly selective medium for isolation of Listeria monocytogenes from food; al-Zoreky N et al.; A new selective medium (Al-Zoreky-Sandine listeria medium {ASLM}) was formulated to recover Listeria monocytogenes from food specimens; the medium completely inhibited common food microflora . Recognition of Listeria colonies is evident by black discoloration of the medium due to esculin hydrolysis without need for special illuminating equipment . The medium contains acriflavin, ceftazidime, and moxalactam as selective agents . Compared with Listeria Selective Agar, ASLM was equally effective in recovering L . monocytogenes . However, ASLM inhibited micrococci, enterococci, and gram-negative bacteria, especially a strain that mimicked L . monocytogenes on Listeria Selective Agar . The new medium was able to recover heat injured cells with only 15% less count than the nonselective medium.

Appl Environ Microbiol, 1990 Oct, 56(10), 3101 - 4
Incidence and characterization of Listeria monocytogenes in foods available in Taiwan; Wong HC et al.; A variety of foods were examined for the incidence of Listeria monocytogenes, and the bacterial isolates were further characterized . L . monocytogenes was selected on LiCl-phenylethanol-moxalactam agar after enrichments and identified by several biochemical, mobility, and CAMP tests . L . monocytogenes was isolated from 58.8% of pork samples, 50% of chicken carcasses, 38% of turkey parts, 34% of frozen semiready foods, 24% of beef steaks, 12.2% of vegetables, 10.5% of seafoods, and 4.4% of frozen dim sum but was not found in the Chinese pickles and fermented milks . Isolates from seafoods, turkey parts, and beef samples had higher hemolytic activity than those from other samples . The isolates were highly susceptible to ampicillin, cephalothin, chloramphenicol, erythromycin, gentamicin, kanamycin, neomycin, novobiocin, penicillin, and streptomycin . About 14.5% of the isolates were resistant to methicillin, and 14.5% were resistant to tetracycline . The majority of the isolates from turkey parts and beef steaks were serotype 1, and those from chicken and pork samples were serotype 4 and others . Hemolytic activity, methicillin susceptibility, and serotype distribution of the isolates from domestic and imported food samples were significantly different . The results suggest the presence of food- or geography-specific L . monocytogenes strains.

Eur J Clin Microbiol Infect Dis, 1990 Oct, 9(10), 767 - 70
In vitro antimicrobial susceptibility of Listeria monocytogenes isolated in the UK and other Listeria species; MacGowan AP et al.; The MICs and MBCs of 21 antimicrobial agents were determined for 103 strains of Listeria monocytogenes isolated in the UK and 27 strains of other Listeria species . Ampicillin, penicillin, azlocillin, imipenem, gentamicin, netilmicin, amikacin, erythromycin, rifampicin, trimethoprim, clindamycin and vancomycin had good activity, while cephalothin, chloramphenicol, ciprofloxacin and ofloxacin were less active, and cefuroxime, enoxacin, norfloxacin and fosfomycin were the least active . Tetracycline had good activity against many strains, but the MIC was high for some . Unlike the other Listeria species tested, Listeria ivanovii was susceptible to fosfomycin . Inoculum size and media employed were shown to affect the MBC, tryptose phosphate broth yielding higher MBCs than Mueller-Hinton or Isosensitest broths.

Can J Microbiol, 1990 Oct, 36(10), 697 - 703
Petite colony formation by Listeria monocytogenes and Listeria species grown on esculin-containing agar; Siragusa GR et al.; Several strains of Listeria species formed petite-sized colonies from parent stock cultures when grown on agar media containing 0.2-1% (w/v) esculin . This was observed in Listeria monocytogenes (7/22 strains), L . innocua (1/3), L . grayi (1/1), L . seeligeri (1/3), and L . welshimeri (1/1), but not in L . ivanovii (0/1) and L . murrayi (0/1) . This phenomenon was only observed on agar media that contained esculin . All petite isolates had biotyping profiles identical to their larger, normal-sized counterpart isolates . Normal and petite-sized isolates from two L . monocytogenes strains, Scott A and V7, were pathogenic to immunosuppressed white mice . On media containing 0.5% (w/v) esculin + ferric iron, Listeria cultures produced colony diameters intermediate in size between those of normal and petite cultures . When pregrown in glucose broth, all petite isolates demonstrated visible beta-glucosidase (esculinase) activity within 5 min, while the normal-sized isolates showed beta-glucosidase activity only after at least 20-70 min . This evidence suggests that cells forming petite colonies are beta-glucosidase constitutive variants within the parent population, while cells that form normal-sized colonies are inducible for beta-glucosidase (esculinase) activity . A possible role for the esculin hydrolysis product, esculetin, in causing petite colony formation is discussed.

Can J Microbiol, 1990 Oct, 36(10), 671 - 5
Studies on cytokine activation of listericidal activity in murine macrophages; Denis M et al.; The ability of a variety of soluble factors, alone or in combination, to endow murine resident peritoneal macrophages with listericidal activity was assessed . Inhibition of growth and (or) killing of Listeria in infected macrophages was determined by the uptake of {3H}uracil following lysis of the infected macrophage monolayers . Interferon-gamma was shown to induce modest listericidal activity in murine resident macrophages as compared with untreated monolayers . Treatment with tumour necrosis factor alpha also induced significant listericidal activity in this system . Among other cytokines tested, IL-4 induced an ability to inhibit growth of Listeria in resident macrophages . The ability of cytokines tested, IL-4 induced an ability to inhibit growth of Listeria in resident macrophages . The ability of cytokines to act in an additive or synergistic fashion with IFN-gamma was also investigated . Combinations of IFN-gamma and IL-4 and IFN-gamma and IL-2 induced listericidal activity not greater than that seen with IFN-gamma alone . IFN-gamma and TNF-alpha were shown to increase bactericidal activity in an additive fashion . However, elicited macrophages were shown to spontaneously exert a significant listericidal activity that was not enhanced by cytokine treatment . Collectively, these findings show that cytokine treatment induced rather modest enhancement in listericidal activity in murine resident peritoneal macrophages and no enhancement whatsoever in elicited macrophages . Thus, in in vivo situations where Listeria organisms are completely cleared from the infected organs, mechanisms other than lymphokine-induced listericidal activity of resident macrophages would seem to be operating.

Epidemiol Infect, 1990 Oct, 105(2), 245 - 54
A comparative study of clinical and food isolates of Listeria monocytogenes and related species; Szabo EA et al.; Ninety-six isolates of presumptive or confirmed Listeria monocytogenes were obtained from local clinical (30 isolates) or food laboratories (66 isolates) . Minimal biochemical analysis identified only 80% of these isolates as L . monocytogenes the remaining included L . seeligeri, 1%, or the non-haemolytic L . innocua, 19% . The 27 clinical and 50 food isolates, mainly from meat products, frozen confectionaries, and cheeses, confirmed as L . monocytogenes were compared biochemically and serologically . Twenty-one isolates, including some strains of L . innocua and L . seeligeri, were examined for pathogenicity in immunocompromized mice and 44 typed using bacterial restriction endonuclease DNA analysis (BRENDA) . Only isolates of L . monocytogenes were found to be pathogenic . Biovar-typing of the isolates was unreliable and provided poor discrimination . Serogroups 1/2 and 4 predominated among clinical and food isolates and BRENDA provided better discrimination among isolates . Ten stable and reproducible restriction patterns were observed among the Listeria sp . isolates studied . Overall, a combination of techniques gave the best discrimination and indicated their potential for use as epidemiological tools.

Immunol Cell Biol, 1990 Oct, 68 ( Pt 5), 289 - 97
Distinction between 'inflammatory' and 'immune' macrophages killing Listeria monocytogenes in murine infection; Tran HT et al.; Two populations of efficiently phagocytic and bacteriolytic cells have been defined in the peritoneal cavity following infection of mice with Listeria monocytogenes . One was the result of a transient inflammatory response 2 days after intraperitoneal (i.p.) infection . It consisted of a mixture of monocyte/macrophages and neurotrophils which, when separated on Percoll gradients or by adherence, were both highly bacteriolytic compared with normal resident peritoneal macrophages . It was rich in recently divided cells as evidenced by in vivo labelling with tritiated thymidine . Although having the enlarged, vacuolated appearance of 'activated' macrophages, three-quarters of the monocyte/macrophages stained positive for myeloperoxidase (MPO), characteristic of monocytes rather than mature macrophages . In contrast, intravenous (i.v.) infection, which localizes in spleen and liver, did not produce this early response in the peritoneal cavity . However, 8 days after either i.v . or i.p . infection there existed in the peritoneal cavity a highly active population of cells comprising chiefly macrophages of typical foamy appearance which did not stain for MPO+ . They were actively phagocytic and bacteriolytic and, like the early inflammatory exudate, produced increased amounts of oxygen degradative products . They appear to typify the concept of macrophages activated by T cell mediated immunity . Two day peritoneal exudates induced in these previously infected mice by i.p . rechallenge with L . monocytogenes organisms comprised mostly MPO- macrophages.

Gene, 1990 Sep 28, 94(1), 129 - 32
High-efficiency transformation of Listeria monocytogenes by electroporation of penicillin-treated cells; Park SF et al.; A procedure has been developed for electroporation-mediated transformation of Listeria monocytogenes with plasmid DNA . The method was optimized for intact cells of L . monocytogenes 23074 by determining the effects of field strength, cell density, and plasmid DNA topology . Transformation efficiencies were dramatically increased when cells were treated with penicillin . Optimum frequencies of transformation (4 x 10(6) transformants/microgram DNA) were obtained when cells were grown in 10 micrograms/ml of penicillin G and electroporated at a field strength of 10 kV/cm . Using this procedure, transformation of relaxed plasmid DNA from ligation reactions provided 1 x 10(4) transformants/microgram DNA, allowing direct molecular cloning of DNA into this organism.

Rev Infect Dis, 1990 Sep-Oct, 12(5), 820 - 3
Listerial myocarditis in cardiac transplantation; Stamm AM et al.; Clinical signs of heart failure developed in two cardiac transplant recipients and were interpreted initially as graft rejection . Morphologic examination of explanted hearts revealed myocarditis with abscess formation and necrosis consistent with a bacterial process; Listeria monocytogenes was isolated from myocardial tissue in the first case and from blood in both . The first patient also developed signs of meningoencephalitis, but the second had no signs of infection outside the heart . Antimicrobial therapy and retransplantation were successful in eradicating listeriosis . The differential diagnosis of heart failure in cardiac transplant recipients includes infectious myocarditis due to L . monocytogenes.

J Toxicol Environ Health, 1990 Sep, 31(1), 53 - 70
Surface morphology and morphometry of rat alveolar macrophages after ozone exposure; Dormans JA et al.; As the ultrastructural data on the effects of ozone on pulmonary alveolar macrophages (PAM) are lacking, transmission (TEM) and scanning (SEM) electron microscopy were performed on rat PAM present in alveolar lavages following exposure to ozone . Rats were continuously exposed for 7 d to ozone concentrations ranging from 0.25 to 1.50 mg/m3 for 7 d followed by a 5-d recovery period . Additionally, morphometry on lung sections was performed to quantitate PAM . In a second experiment rats were continuously exposed to 1.50 mg O3/m3 for 1, 3, 5, or 7 d . To study the influence of concurrent ozone exposure and lung infection, due to Listeria monocytogenes, rats were exposed for 7 d to 1.50 mg O3/m3 after a Listeria infection . The surface area of lavaged control PAM was uniformly covered with ruffles as shown by SEM and TEM . Exposure to 0.5 mg ozone/m3 for 7 d resulted in cells partly covered with microvilli and blebs in addition to normal ruffles . The number of large size PAM increased with an increase in ozone concentration . After 1 d of exposure, normal-appearing as well as many small macrophages with ruffles and scattered lymphocytes were seen . Lavage samples taken after 5 or 7 d of exposure showed an identical cell composition to that taken after 3 d of exposure . After Listeria infection alone, lavage samples consisted of mainly lymphocytes and some macrophages . Small quantitative changes, such as an increase in the number of polymorphonuclear neutrophils and large-size PAM, occurred in lavages after ozone exposure and infection with L . monocytogenes . Morphometric examination of lung sections revealed a concentration-related increase in the number of PAM, even in animals exposed to 0.25 mg ozone/m3 for 7 d . Centriacinar regions were more severely affected than other regions of lung tissue . By 5 d after termination of exposure to ozone, the number of lysozyme-positive alveolar cells was still significantly increased in centriacinar areas of the lung . The results indicate that ozone exposure causes major changes in the number, size, and surface morphology of PAM in rat lung . Furthermore, the results presented here suggest that changes in alveolar macrophage function are reflected by morphological changes.

J Clin Periodontol, 1990 Sep, 17(8), 575 - 9
Comparative effects of 2 chemotherapeutic mouthrinses on the development of supragingival dental plaque and gingivitis; Overholser CD et al.; A 6-month double-blind, controlled clinical study was completed with 124 healthy adult subjects to determine the efficacy of 2 mouthrinses, Listerine (LA) and Peridex (PX), used as supplements to regular oral hygiene measures in reducing supragingival dental plaque and gingivitis . Following screening examinations for entry levels of existing gingivitis and plaque, baseline gingival and plaque area indices, extrinsic tooth stain, supragingival calculus, bleeding and soft tissue condition were recorded . All subjects then received a complete dental prophylaxis to remove plaque, calculus and extrinsic stain . Subjects were randomly assigned to 1 of 3 groups and performed supervised rinses twice daily for 30 s in addition to their normal oral hygiene, for 6 months . All indices were again evaluated at 3 and 6 months . After 6 months, LA and PX significantly (p less than 0.001) inhibited development of plaque by 36.1% and 50.3%, respectively, and the development of gingivitis by 35.9% and 30.5%, respectively, compared to a hydroalcohol control . PX was more effective in inhibiting plaque and both mouthrinses appeared to be equally effective in inhibiting gingivitis . LA patients did not develop significant levels of stain or supragingival calculus at 6 months, compared to baseline or control . PX patients developed significant levels of extrinsic stain and supragingival calculus compared to baseline and control . Though PX was more effective than LA in the control of plaque, this study indicates that both LA and PX were effective agents in a regimen for the control of plaque and gingivitis.

Rev Clin Esp, 1990 Sep, 187(4), 175 - 7
{The seroprevalence of Listeria infections without clinical sign in a population of pregnant women from the Reus area}; Pujol I et al.; We describe the results of a study of asymptomatic Listeria monocytogenes serum prevalence in a population of pregnant women in the Reus area . The study includes newborn exam and correlation with laboratory data obtained by an indirect immunofluorescence method recently developed . The incidence of anti-Listeria antibody carriers was high (12%) but in no cases spontaneous abortions or fetal malformations were associated to high titers.

Antimicrob Agents Chemother, 1990 Sep, 34(9), 1695 - 8
Alteration of PBP 3 entails resistance to imipenem in Listeria monocytogenes; Pierre J et al.; A mutant with decreased susceptibility to imipenem (IpR) was selected in vitro from a susceptible clinical isolate of Listeria monocytogenes (IpS) . IpR exhibited decreased susceptibility to penicillin G (4 x MIC) and imipenem (16 x MIC) and increased susceptibility to cefotaxime (0.25 x MIC) . Electrophoretic profiles of membrane proteins and penicillin-binding proteins (PBPs) were identical in the two strains; each strain had five PBPs with molecular masses of ca . 97, 83.3, 81, 77.1, and 42.6 kilodaltons . A decreased affinity of PBP 3 for penicillin G and imipenem (10-fold) was observed in IpR . In contrast, the affinity of PBP 3 for cefotaxime in IpR was increased twofold and correlated with the decreased MIC of this drug . From these findings and competition experiments with different beta-lactam antibiotics, we conclude that the alteration of PBP 3 is responsible for the decreased susceptibility of IpR to penicillin and imipenem and that PBP 3 might be an essential target of beta-lactam antibiotics in L . monocytogenes.

Appl Environ Microbiol, 1990 Sep, 56(9), 2930 - 2
Detection of Listeria monocytogenes by using the polymerase chain reaction; Bessesen MT et al.; A method was developed for detection of Listeria monocytogenes by polymerase chain reaction amplification followed by agarose gel electrophoresis or dot blot analysis with a 32P-labeled internal probe . The technique identified 95 of 95 L . monocytogenes strains, 0 of 12 Listeria strains of other species, and 0 of 12 non-Listeria strains.

Appl Environ Microbiol, 1990 Sep, 56(9), 2807 - 10
Catalase, superoxide dismutase, and hemolysin activities and heat susceptibility of Listeria monocytogenes after growth in media containing sodium chloride; Dallmier AW et al.; The activities of catalase, superoxide dismutase, and a thiol-activated hemolysin produced by four strains of Listeria monocytogenes propagated in media containing various concentrations of sodium chloride were examined . L . monocytogenes 7644 showed an increase in catalase, superoxide dismutase, and thiol-activated hemolysin activities when grown in a medium containing 2.5% (wt/vol) NaCl followed by a decrease in activities when propagated in media containing salt concentrations higher than 2.5% . L . monocytogenes LCDC 81-861 demonstrated enhanced catalase activity when grown in media containing NaCl ranging from 1.5 to 4.6% and increased superoxide dismutase activity when propagated in media containing 1.5 to 3.5% NaCl . L . monocytogenes LCDC 81-861 did not exhibit any detectable hemolysin activity under the conditions tested . After growth in various NaCl-containing media, both strains were subjected to sublethal heat injury for 30 min at 55 degrees C . L . monocytogenes LCDC 81-861 showed increased sensitivity to the heat treatment when grown in media containing 4.6 and 6.5% NaCl, whereas L . monocytogenes 7644 did not exhibit enhanced heat lability.

J Med Microbiol, 1990 Sep, 33(1), 51 - 4
Ingested Listeria monocytogenes survive and multiply in protozoa; Ly TM et al.; Listeria monocytogenes cells are ingested by protozoa such as Acanthamoeba sp . or Tetrahymena pyriformis . However, they are not killed, but survive within the protozoa and may multiply intracellularly . The protozoa are lysed within about 8 days, releasing viable L . monocytogenes . No co-existence was observed between L . monocytogenes and Tetrahymena . A co-culture of L . monocytogenes and Acanthamoeba sp . showed a decay of locomotive forms and release of listeria from vegetative protozoan cells whereas the bacteria were destroyed in cysts . These phenomena provide an insight into the pathogenesis of listeria infection in man and warm-blooded animals because intracellular processes occurring in protozoa after ingestion of L . monocytogenes may be similar to those observed in mammalian cells.

Eur J Clin Microbiol Infect Dis, 1990 Sep, 9(9), 659 - 63
Western blot analysis of the antibody response in patients with Listeria monocytogenes meningitis and septicemia; Renneberg J et al.; The antibody response in patients with Listeria monocytogenes septicemia and/or meningitis was investigated using Western blot analysis (WBA) . Protein antigen preparations were produced from two strains of Listeria monocytogenes, representing serogroup 1 and 4, by sonication and differential centrifugation . IgG antibodies from 8 (50%) of 16 patients with culture verified septicemia and/or meningitis due to Listeria monocytogenes reacted with a 93 kDa antigen from serogroup 1, in contrast to IgG antibodies from only 1 (2%) of 51 controls; these controls represented 21 patients with infections caused by other bacteria and 30 apparently healthy blood donors . Furthermore, IgM antibodies from 3 (19%) of the patients with listeric infections bound to a 106 kDa protein antigen in contrast to none of the controls . In 3 (33%) of 9 patients from whom acute and convalescence serum were available, the patients responded by producing antibodies against new protein antigens . Current methods used in routine serological investigations, i.e . complement fixation and O-agglutination tests, were positive in only 4 (24%) of the 16 patients with listeriosis . The results point to the possibility of designing new immunoassays for detection of septicemia and meningitis caused by Listeria monocytogenes.

Immunology, 1990 Sep, 71(1), 107 - 12
Effects of purified anti-Lyt-2 mAb treatment on murine listeriosis: comparative roles of Lyt-2+ and L3T4+ cells in resistance to primary and secondary infection, delayed-type hypersensitivity and adoptive transfer of resistance; Czuprynski CJ et al.; Mice treated with purified anti-Lyt-2 monoclonal antibody (mAb) displayed a delayed ability to eliminate a primary Listeria monocytogenes infection from their spleens . Elimination of listeriae from the liver was unimpaired by anti-Lyt-2 mAb treatment . Treatment with anti-L3T4 mAb, alone or in combination with anti-Lyt-2 mAb, resulted in similar increases in the numbers of listeriae recovered from the spleens at 7 days after challenge . Listeria-infected mice that had been treated with anti-Lyt-2 mAb alone developed a strong delayed-type hypersensitivity (DTH) response, although it was significantly reduced as compared to control listeria-infected mice . In contrast, treatment with anti-L3T4 mAb severely impaired the development of DTH in listeria-infected mice . Treatment with anti-Lyt-2 mAb and anti-L3T4 mAb, singly or in combination, did not prevent mice from developing increased anti-listeria resistance if they were then immunized with a sublethal dose of L . monocytogenes . Treatment of mice with anti-Lyt-2 mAb or anti-L3T4 mAb before immunization, however, reduced the ability of their spleen cells to transfer anti-listeria resistance to recipient mice . These results indicate that Lyt-2+ cells make substantial contributions to the resistance of mice to primary L . monocytogenes infection, and to the ability of spleen cells from listeria-immunized mice to transfer resistance to naive recipients.

Infect Immun, 1990 Sep, 58(9), 3147 - 50
Hemolysin is required for extraintestinal dissemination of Listeria monocytogenes in intragastrically inoculated mice; Roll JT et al.; In this study we demonstrated that a hemolytic strain of Listeria monocytogenes, but not a nonhemolytic mutant derived from it, translocated in substantial numbers to the mesenteric lymph nodes, spleen, and liver after intragastric inoculation of mice . Growth at 4 degrees C prior to inoculation did not increase the virulence of the nonhemolytic mutant . These results indicate that hemolytic activity is required for the virulence of L . monocytogenes via the gastrointestinal tract, as has been shown previously for parenteral challenge.

Infect Immun, 1990 Sep, 58(9), 2940 - 5
Listeria monocytogenes intragastric and intraperitoneal approximate 50% lethal doses for mice are comparable, but death occurs earlier by intragastric feeding; Pine L et al.; The intraperitoneal (i.p.) and intragastric (i.g.) mouse approximate 50% lethal dose values (ALD50S) were determined for 15 food and clinical isolates of Listeria monocytogenes . Although all strains gave i.g . ALD50S comparable to or less than their i.p . ALD50S, the i.g . feeding of most strains produced more deaths within the first 3 days of the 6-day test than did i.p . injection . ALD50S ranged from 50 to 4.4 x 10(5) cells with approximately 1-log 95% confidence intervals . Of five strains tested by suspension in milk or by growth in milk, none gave i.g . ALD50S that were lower than those of washed cells . Results with 10- to 21-g mice supported the use of 15-g mice for i.g . testing; 21-g mice were more resistant to i.g . infection . These results indicate that i.g . feeding permits an evaluation of the role of the carrier (such as milk) in the determination of listerial virulence, permits strain characterization by i.p . and i.g . ALD50S, and emphasizes a potentially more rapid infection when the bacterium is introduced i.g.

Infect Immun, 1990 Sep, 58(9), 2792 - 803
Cloning and characterization of T-cell-reactive protein antigens from Listeria monocytogenes; Beattie IA et al.; To explore the molecular basis of the T-cell-mediated immune response to Listeria monocytogenes, we cloned and expressed listerial antigens in Escherichia coli using the lambda-ZAP bacteriophage and Bluescript plasmid vectors . A two-stage screening strategy was implemented to identify T-cell-reactive antigens; the first stage involved antibodies or oligonucleotide probes and the second stage was based on assays for T-cell activation . A library of genomic DNA from L . monocytogenes was generated in lambda-ZAP, and then antigens, were detected in infected cells with a polyclonal rabbit anti-L . monocytogenes antiserum and an L . monocytogenes-specific monoclonal antibody . Also, synthetic oligonucleotide probes corresponding to the structural gene for listeriolysin O (LLO) were used to screen the recombinant DNA library . In each case, positive isolates were evaluated for T-cell antigenicity by measuring antigen-induced interleukin-2 production by polyclonal T cells taken from L . monocytogenes-immune mice . Phage clones were subcloned and expressed in the Bluescript plasmid and tested further for antigenic activity and LLO expression . Using this screening strategy, we successfully identified bacterial clones producing recombinant listerial antigens which activate L . monocytogenes-immune T cells in vitro . Antigens operative in the T-cell response during infection with L . monocytogenes include LLO, 62- and 39-kilodalton proteins, and other poorly defined bacterial surface components . We also found that high concentrations of recombinant LLO inhibited macrophage-mediated antigen presentation . These results are discussed in terms of the multiple functions of LLO as a virulence factor, inhibitor of antigen presentation, and potent antigen in the T-cell response to L . monocytogenes . These studies represent the first step toward a genetic definition of the antigens recognized in immune defense to L . monocytogenes.

Vet Microbiol, 1990 Sep, 24(3-4), 341 - 53
Characterization of Listeria monocytogenes isolates by Southern blot hybridization; Wesley IV et al.; A synthetic deoxyribonucleotide probe for virulent Listeria monocytogenes, designated ADO7, was evaluated for its ability to identify restriction fragments of L . monocytogenes with nucleic acid sequences homologous with the beta-hemolysin gene by Southern blot hybridization of clinical and food isolates . The synthetic probe hybridized with three restriction fragments (approximately 1.1, 0.86, and 0.76 kb) of the serotype 1/2A isolates . Southern blot hybridization of the serogroup 4B isolates indicated that the nucleic acid sequences homologous with the beta-hemolysin gene probe were limited to a single restriction fragment of approximately 1 kb.

Eur J Epidemiol, 1990 Sep, 6(3), 319 - 22
Restriction endonuclease analysis of chromosomal DNA from Listeria monocytogenes strains; Casolari C et al.; Restriction endonuclease analysis of chromosomal DNA was applied to thirteen Listeria monocytogenes strains alongside the more conventional typing methods of serotyping and phage typing . The organisms were isolated from cases of sporadic listeriosis (nine strains); from an occasional nosocomial cluster (two strains); and from food samples (two strains) . Purified DNAs were digested with EcoRI restriction endonuclease, and restriction fragments separated by electrophoresis . Restriction patterns correlated well with phage patterns, but also allowed typing of the phage-untypable strains . DNA fingerprinting appears to be a potentially helpful tool for epidemiological investigations of listeric infections, particularly when phage typing fails to determine the identity or diversity of the isolates.

Lett Appl Microbiol, 1990 Sep, 11(3), 158 - 62
Detection of Listeria species and Listeria monocytogenes using polymerase chain reaction; Border PM et al.; Five oligonucleotide sequences are described that were used as primers in the polymerase chain reaction (PCR) to amplify specific sequences from Listeria DNA . When all five primers were used in combination, three PCR products were possible; a Listeria specific product that occurs with DNA from any Listeria sp., a Listeria monocytogenes specific product that occurs only in the presence of DNA from this organism and a universal product that is found using DNA from any bacterial source . The occurrence of these PCR products was used as a diagnostic test on bacteria isolated from various food samples to detect Listeria sp . and L . monocytogenes.

Enferm Infecc Microbiol Clin, 1990 Aug-Sep, 8(7), 414 - 9
{Listeriosis in the adult . Clinical, epidemiological, and therapeutic considerations based on a series of 26 cases}; Hernandez A et al.; The clinico-epidemiological characteristics and therapy in 26 patients with infection produced by Listeria monocytogenes were reported . In 14 cases there was a primary bacteremia and in 12 patients there was a meningeal involvement . In 22 patients a previous disease was detected . Chronic immunosuppressor therapy was present in 13 cases . The most common symptom was the fever associated with meningeal syndrome, decreased consciousness and or focal neurologic involvement in cases with meningitis . In 76.9% of the patients the form of presentation was acute . Cerebrospinal fluid examination revealed an increased number of cells with a predominance of polymorphonuclear elements . Ampicillin and penicillin either single or associated with aminoglycosides were the most used antibiotics . The overall mortality was 30.8%.

Zh Mikrobiol Epidemiol Immunobiol, 1990 Aug, (8), 11 - 6
{The potentiating action of Listeria monocytogenes in relation to endotoxic shock}; Cherkashin GV; The infection of mice with Listeria cells 15 hours prior to the inoculation of endotoxin sharply increased its lethal action . Blood taken from the mice at the peak of the development of shock was toxic for adrenalectomized recipients . This potentiating effect was blocked by hydrocortisone . Carrageenan prolonged the survival time of such animals, but did not change the course of endotoxin shock, as well as toxicosis, caused by listerial aqueous extract in adrenalectomized mice . This potentiating phenomenon plays supposedly a certain role in the genesis of toxicosis in mixed infections (listeriosis in combination with other infections).

Toxicol Appl Pharmacol, 1990 Aug, 105(1), 144 - 55
Immunotoxicity of bis(tri-n-butyltin)oxide in the rat: effects on thymus-dependent immunity and on nonspecific resistance following long-term exposure in young versus aged rats; Vos JG et al.; To investigate whether immune function suppression observed in an earlier study after short-term bis(tri-n-butyltin)oxide (TBTO) exposure also occurred after long-term treatment, function studies for specific and nonspecific resistance were performed after exposure of weaned male rats to diets containing 0, 0.5, 5, or 50 mg TBTO/kg for 4-6 and 15-17 months . Treatment for 4.5 months had no effect on body weight but reduced thymus weight at 50 mg/kg . Regarding the thymus-dependent immunity, delayed-type hypersensitivity reactions to ovalbumin and tuberculin were not depressed, in contrast to the results of the short-term study . The resistance to the nematode Trichinella spiralis was dose-relatedly suppressed at the 5 and 50 mg/kg levels, in both experiments (5.5 and 16.5 months exposure), as shown by increased counts of muscle larvae and depressed serum IgE titers . Also the inflammatory reaction around cysts in parasitized musculature was reduced . No significant reduction was found in IgM and IgG titers to T . spiralis, ovalbumin, and sheep red blood cells as determined by enzyme-linked immunosorbent assay . TBTO exposure at 50 mg/kg for 4.5 months significantly reduced thymus weight, but the response of thymocytes to T-cell mitogens was unaltered . TBTO treatment for 4.5 or 16 months did not influence the response of spleen cells to T-and B-cell mitogens and neither influenced spleen weight . A dose-related shift was observed in T- and B- cell numbers in mesenteric lymph nodes as shown by flow cytometry using monoclonal antibodies: treatment for 6 and 18 months reduced the relative count of T-lymphocytes and consequently increased the percentage of B-lymphocytes . As a result, the T:B ratio was reduced in the 5 and 50 mg/kg groups . Concerning the nonspecific resistance, TBTO exposure for 5 and 17 months reduced macrophage function at 50 mg/kg as shown by impaired splenic clearance of Listeria monocytogenes bacteria . Natural cell-mediated cytotoxicity of spleen and peritoneal cells was investigated in a 51Cr-release assay with YAC-lymphoma target cells . TBTO treatment significantly suppressed natural killer (NK) activity in spleen cells . Significant suppression was noted in all treatment groups following 16 months TBTO exposure; in contrast to treatment for 4.5 months . No significant alterations were observed in the spontaneous cytotoxicity of nonadherent and adherent peritoneal cells following 4.5 months treatment . Treatment of aged (i.e., 1-year-old) male rats for 5 months with the 50 mg/kg diet reduced thymus weight but had no effect on body or spleen weight.(ABSTRACT TRUNCATED AT 400 WORDS)

Proc Natl Acad Sci U S A, 1990 Aug, 87(16), 6068 - 72
Listeria monocytogenes moves rapidly through the host-cell cytoplasm by inducing directional actin assembly; Dabiri GA et al.; Listeria monocytogenes is an intracellular parasite that can readily infect the macrophage-like cell line J774 and the kidney epithelial cell PtK2 . After being ingested, the organism escapes from the phagolysosome into the host-cell cytoplasm . N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)-phallacidin, a specific stain for actin filaments (F-actin), demonstrates that within 1 hr of initiation of infection, the bacteria become surrounded by host-cell cytoplasmic actin filaments . By 3 hr, long projections of F-actin begin to form at one end of the bacteria . These actin structures colocalize with the actin-bundling protein alpha-actinin as well as with tropomyosin . Microinjection of fluorescently labeled alpha-actinin in living cells demonstrates that the formation of these F-actin projections is associated with bacterial movement, actin filaments rapidly assembling behind the bacteria as they migrate through the cytoplasm . These F-actin tails attain lengths up to 40 microns . The movement of the bacteria through the cytoplasm is rapid, 0.12-1.46 microns/sec . Within 2 min of cytochalasin D (0.5 micrograms/ml) treatment, all bacterial intracellular movement stops, and additional bacteria-associated actin assembly is blocked . A nonmotile Listeria mutant induces comparable actin assembly and moves at speeds similar to the wild type, indicating that the forces required for intracellular bacterial movement are generated by the host cell . L . monocytogenes can dramatically stimulate host-cell actin assembly in a directional manner, which serves to rapidly propel the bacteria through the cytoplasm, allowing the organisms to move to peripheral membranes and spread to uninfected cells.

Infect Immun, 1990 Aug, 58(8), 2715 - 8
Iron acquisition systems of Listeria monocytogenes; Adams TJ et al.; The uptake of iron by Listeria monocytogenes was studied . The microorganism was found to bind both 59Fe(II) and {59Fe3+}citrate . In contrast, L . monocytogenes was unable to acquire iron from {59Fe3+}ferroxamine or {59Fe3+}EDTA or as 59FeCl3 . The data suggest that iron is acquired principally as iron(II) and that a citrate-inducible iron uptake system is also operative.

Immunology, 1990 Jul, 70(3), 411 - 3
In vivo IL-1 potentiates both specific and non-specific arms of immune response to infection; Cheers C et al.; Injection of 10(5) U interleukin-1 (IL-1) 4 hr before intravenous infection with Listeria monocytogenes hastens recovery of mice . This is accompanied not only by early stimulation of colony-forming cells in the spleen to levels higher than those in untreated, infected mice but also by accelerated activation of lymphokine-producing, specific T lymphocytes.

Mol Microbiol, 1990 Jul, 4(7), 1091 - 9
Characterization of a Listeria monocytogenes-specific protein capable of inducing delayed hypersensitivity in Listeria-immune mice; Gohmann S et al.; Recovery of the host after infection by the intracellular pathogen Listeria monocytogenes is dependent on cell-mediated immunity . Little is known of the nature of listerial antigens that induce cell-mediated responses in the infected host . In this study we report on the identification and cloning of an Escherichia coli recombinant encoding a listerial antigen, designated ImaA, capable of eliciting a specific delayed-type hypersensitivity response in Listeria-immune mice . Nucleotide sequencing of the Listeria DNA insert in plasmid pLM10 showed that the ImaA gene product consisted of 170 amino acids with a molecular weight of 17,994 . The predicted amino acid sequence suggests that the protein is localized to the bacterial plasma membrane or cell wall . The ImaA gene was unique to the pathogenic species L . monocytogenes and Listeria ivanovii; it was not present in any other species of the genus Listeria.

J Biolumin Chemilumin, 1990 Jul-Sep, 5(3), 179 - 82
Enhanced chemiluminescence ELISA for Listeria specific antigen in cerebrospinal fluid using an FITC-anti-FITC system; Samuel D et al.; An enzyme-linked immunosorbent assay (ELISA) is described for the detection of a soluble Listeria monocytogenes serogroup 4 antigen in cerebrospinal fluid samples (CSFs) . In the ELISA an anti-Listeria monoclonal antibody, immobilized onto assay wells, was used to capture antigen from CSFs, the captured antigen was then reacted with a fluorescein isothiocyanate (FITC) conjugate of the same anti-Listeria antibody, which was detected with a horseradish peroxidase conjugate of a monoclonal antibody to FITC . The presence of antigen was detected by an enhanced chemiluminescence assay using a camera luminometer . Antigen was detected in the CSFs taken from five out of seven patients with culture proven L . monocytogenes serogroup 4 central nervous system infections, and in none of the CSFs taken from 25 other patients.

J Appl Bacteriol, 1990 Jul, 69(1), 63 - 72
The effect of pH, salt concentration and temperature on the survival and growth of Listeria monocytogenes; Cole MB et al.; Factorially designed experiments have been used to study the growth and survival of Listeria monocytogenes in different combinations of pH and salt concentrations at ambient and chill temperatures . Survival at low pH and high salt concentration was strongly temperature dependent . The minimum pH values that allowed survival after 4 weeks from an initial 10(4) cells were 4.66 at 30 degrees C, 4.36 at 10 degrees C and 4.19 at 5 degrees C . These limits were salt dependent, low (4-6%) salt concentrations improved and higher concentrations reduced survival at limiting pH values . The lowest pH that allowed a 100-fold increase in cell numbers within 60 d was 4.66 at 30 degrees C but this was increased to 4.83 at 10 degrees C . At 5 degrees C growth occurred at pH 7.0 but not at pH 5.13 . Simple predictive models describing the effect of hydrogen-ion and salt concentration on the time for at least a 100-fold increase in numbers at 10 degrees C and 30 degrees C were constructed after analysis of the results for a least squares fit to a quadratic model . The interactions between salt and hydrogen-ion concentration on growth were found to be purely additive.

Appl Environ Microbiol, 1990 Jul, 56(7), 2274 - 5
Replica plating of colonies from Listeria-selective agars to blood agar to improve the isolation of Listeria monocytogenes from foods; Cassiday PK et al.; Bacterial colonies from Listeria-selective agars were replica plated to sheep blood agar to screen for beta-hemolysis . By using the replica plating method to test for the beta-hemolytic characteristic of all the colonies growing on Listeria-selective agars instead of picking 3 to 10 suspected colonies for further testing, we recovered Listeria monocytogenes from 59 of 142 Listeria-selective agar plates which contained colonies of hemolytic and nonhemolytic Listeria species and were negative when tested by conventional colony picks.

Appl Environ Microbiol, 1990 Jul, 56(7), 2133 - 41
Analysis of clinical and food-borne isolates of Listeria monocytogenes in the United States by multilocus enzyme electrophoresis and application of the method to epidemiologic investigations; Bibb WF et al.; To investigate the microbiology and epidemiology of the 1,700 sporadic cases of listeriosis that occur annually in the United States, we developed a multilocus enzyme electrophoresis (MEE) typing system for Listeria monocytogenes . We studied 390 isolates by MEE . Eighty-two electrophoretic types (ETs) were defined . Two distinct clusters of ETs, ET group A (ETGA) and ET group B (ETGB), separated at a genetic distance of 0.440, were identified . Strains of ETGB were associated with perinatal listeriosis (P = 0.03) . All strains of H antigen type a were in ETGA, while all strains of H antigen type b were in ETGB . Among 328 clinical isolates from cases of literiosis, 55 ETs of L . monocytogenes were defined . Thirty-four ETs were identified among 62 isolates from food products . The mean number of strains per ET (5.2) was significantly higher among clinical isolates than among food-borne isolates . Examination of isolates from outbreaks further documented the link between cases and contaminated food products . In one investigation, we found 11 different ETs, ruling out a single common source as a cause of that outbreak . By examining a large number of isolates collected over a specified time in diverse geographic locations in the United States, we have begun to establish a baseline for the study of the epidemiology of listeriosis by MEE.

Appl Environ Microbiol, 1990 Jul, 56(7), 2007 - 11
Listeria species in a California coast estuarine environment; Colburn KG et al.; Listeria species and L . monocytogenes were found in 81 and 62%, respectively, of fresh or low-salinity waters (37 samples) in tributaries draining into Humboldt-Arcata Bay, Calif., during a winter (January-February) sampling period . The incidence of Listeria species and L . monocytogenes in sediment (46 samples) from the same sites where water was sampled was 30.4 and 17.4%, respectively . One of three bay water samples contained Listeria species (including L . monocytogenes), while of 35 samples of oysters examined, only 1 was found positive for Listeria species (L . innocua) . A given species or L . monocytogenes serogroup appeared to predominate in fresh water when domesticated animals (cows, horses) were nearby, whereas greater variety with no species predominance was observed in areas with no direct animal influence.

Z Lebensm Unters Forsch, 1990 Jul, 191(1), 16 - 9
Overlay technique for direct detection and identification of haemolytic Listeria on selective plating medium . Comparison of five media; Dominguez L et al.; An overlay technique is proposed for the identification and counting of haemolytic Listeria colonies directly on selective plating media . The technique was applied to different Listeria-selective plating media . In pure culture studies with collection strains, the overlay technique was more efficient and reliable for detection haemolytic Listeria species compared with the incorporation of blood into the agar . The efficacy of the overlay technique for the direct detection of haemolytic colonies of Listeria from raw milk samples was related to agar selectivity . The best results were obtained with Listeria-selective agar medium modified (LSAMM) . Catalase assay, together with reactions for aesculin and tellurite, were useful and reliable criteria for the identification of Listeria . All colonies on LSAMM which were positive for catalase, tellurite and aesculin while those displaying typical haemolysis corresponded in most cases to L . monocytogenes.

Infect Immun, 1990 Jul, 58(7), 2386 - 8
Evidence that endogenous gamma interferon is produced early in Listeria monocytogenes infection; Nakane A et al.; It has been presumed that gamma interferon (IFN-gamma), which plays an essential role in antilisterial resistance, is produced late in Listeria monocytogenes infection . In the present study, however, IFN-gamma was detected in the bloodstreams and spleens of mice from days 1 to 4 of L . monocytogenes infection by both a double-sandwich enzyme-linked immunosorbent assay and an immunohistochemical technique, suggesting that endogenous IFN-gamma is produced early but not late in L . monocytogenes infection.

Infect Immun, 1990 Jul, 58(7), 2313 - 9
Accessory function of Kupffer cells in the antigen-specific blastogenic response of an L3T4+ T-lymphocyte clone to Listeria monocytogenes; Gregory SH et al.; The function of Kupffer cells in the development of protective immunity to infection by Listeria monocytogenes is controversial . To determine their role in antilisterial host defenses, Kupffer cells were separated from other nonparenchymal cells of the liver by centrifugation on a metrizamide gradient followed by adherence to glass or plastic . The resultant highly enriched Kupffer cell population supported the antigen-specific blastogenic response {( 3H}thymidine incorporation) of cloned L3T4+ T lymphocytes to L . monocytogenes in vitro . Blastogenesis was dependent upon the duration of the incubation period, the concentration of the antigen, and the number of Kupffer cells in culture . Maximum reactivity was greater than that observed when the same T-cell population was incubated with adherent peritoneal exudate cells and antigen under optimal conditions . The addition of antibodies specific for murine interleukin-1 beta to cocultures of Kupffer cells and T lymphocytes eliminated the antigen-stimulated incorporation of {3H}thymidine, indicating a requirement for interleukin-1 . Analysis of the culture supernatants demonstrated that, in addition to interleukin-1, granulocyte-macrophage colony-stimulating factor, interleukin-6, and gamma interferon were elaborated in cocultures containing cloned T lymphocytes, Kupffer cells, and antigen . These results suggest that Kupffer cells may serve a critical role in the development of immunity to infection by L . monocytogenes in vivo.

Clin Immunol Immunopathol, 1990 Jul, 56(1), 124 - 9
Fish oil dietary supplementation reduces Ia expression in rat and mouse peritoneal macrophages; Mosquera J et al.; Preliminary studies suggest that administration of fish oil fatty acids may be beneficial in several immunological diseases; therefore, we studied the effect of fish oil dietary supplementation on the expression of Ia in stimulated murine peritoneal macrophages . Rats (n = 19) and mice (n = 27) on standard rodent feeding were separated in experimental (E) and control (C) groups that received fish oil or saline solution, respectively, daily for 4 weeks by esophageal gavage . Cholesterol serum levels were significantly lowered by fish oil (E vs C, P less than 0.01) . E and C groups were injected intraperitoneally with Listeria monocytogenes (LM) and peritoneal cells were harvested 4 and 7 days after infection . Decreased expression of Ia induced by LM was found in rats (C = 49.68 +/- 5.09%, E = 16.95 +/- 4.3%, P less than 0.01) and mice (C = 47.38 +/- 7.63%, E = 26.66 +/- 1.92%, P less than 0.01) . Animals with a more pronounced depression of serum cholesterol (reduction of 44.04 +/- 1.52% of baseline levels) had more depression of Ia expression (6.47 +/- 1.22%, P less than 0.001 vs control) . Reduction of Ia expression was not related to PGE2 production by peritoneal cells . Reduction of Ia expression by fish oil could induce down-regulation of antigen presentation and alloreactivity.

J Immunol, 1990 Jul 1, 145(1), 8 - 12
Induction of macrophage-mediated tumor cytotoxicity by a hamster monoclonal antibody with specificity for lipopolysaccharide receptor; Chen TY et al.; Experiments have been carried out to assess the immunostimulatory activity of a hamster IgM mAb (mAb5D3) with specificity for an 80-kDa LPS-binding protein expressed on murine macrophages and monocytes . The addition of mAb5D3 to cultures of murine bone marrow-derived macrophages activated these cells to become tumoricidal for mastocytoma cells in vitro . The activity of mAb5D3 was enhanced in the presence of IFN-gamma . Neither mAb5D3 nor LPS were able to activate macrophages from the LPS-hyporesponsive C3H/HeJ mouse, although these cells responded normally to heat-killed Listeria monocytogenes . The results of several experiments establish that the observed LPS-like activity of mAb5D3 was not due to contaminating endotoxin: 1) the activity of mAb5D3 but not LPS was heat labile at 100 degrees C; 2) the activity of LPS but not mAb5D3, was inhibited by addition of polymyxin B; and 3) quantitative estimates of endotoxin contamination by Limulus amoebocyte lysate reactivity . These experiments thus demonstrate that mAb5D3 can serve as an agonist for LPS-dependent macrophage responses and, when considered with those of our companion paper showing specificity of mAb5D3 for the 80-kDa LPS-binding protein, provide strong support for the concept that the 80-kDa LPS-binding protein previously identified serves as a functional receptor for LPS on murine macrophages.

Changgeng Yi Xue Za Zhi, 1990 Jun 20, 13(2), 152 - 6
{Perinatal listeriosis--a case report}; Cheng BR et al.; Listeria monocytogenes, an uncommon perinatal infection in human, has been reported to be correlated with abortion, premature labor, intrauterine fetal sepsis, intrauterine fetal death and neonatal infections . Reported here was the first case of perinatal listeriosis complicated with Listeria monocytogenes chorioamnionitis at 33 weeks' gestation in Taiwan . The transabdominal amniocentesis in this particular case confirmed the diagnosis . An live premature male fetus was delivered by emergency cesarean section on the next day of hospitalization due to acute fetal distress . The acute ill baby developed signs of meningitis on the following day . Blood culture of Listeriosis monocytogenes indicated early onset neonatal listeriosis . Brain sonography showed hydrocephalus after a one-month period antibiotic treatment, he was lost to follow-up one month later . A review of the literature is presented to describe the clinical, epidemiological and pathological findings and to highlight their variable presentations and procedures for management . Thus it is of great importance for obstetricians to include listeriosis as a differential diagnosis in cases of fever of unknown origin during pregnancy . Promptly obtaining proper cultures and instituting appropriate antibiotics therapy is emphasized.

J Immunol, 1990 Jun 15, 144(12), 4888 - 97
Docosahexaenoic acid, a constituent of rodent fetal serum and fish oil diets, inhibits acquisition of macrophage tumoricidal function; Dustin LB et al.; Macrophage (M phi) activation is deficient in the fetus and neonate, at times when the serum concentration of docosahexaenoic acid (DHA; 22:6n3) is approximately 10-fold higher than in the adult . We tested the effects of highly purified DHA on M phi activation in vitro . M phi were stimulated with rIFN-gamma plus either of two second or "triggering" signals, LPS or heat-killed Listeria monocytogenes . M phi activation was assayed as the lysis of P815 mastocytoma cells, which are resistant to TNF-alpha . DNA inhibited the activation of peritoneal M phi and the M phi line RAW264.7 in a dose-dependent manner at concentrations between 20 and 160 microM . These concentrations are found in fetal and neonatal rodent sera . Another polyunsaturated fatty acid, arachidonic acid (20:4n6), was much less inhibitory . In contrast to its profound effect on tumoricidal activation, DHA did not inhibit phagocytosis and catabolism of 125I-heat-killed Listeria monocytogenes . Increasing the rIFN-gamma or second signals reduced the inhibition of tumoricidal activation by DHA but not M phi incorporation of 14C-DHA . When the rIFN-gamma and second signals were separated in time, DHA was far more inhibitory if delivered with the triggering signal than if delivered with the rIFN-gamma . However, the incorporation of 14C-DHA was the same under these two conditions . In M phi treated with DHA during LPS stimulation, the inhibition was time-dependent, requiring more than 2 h . Although DHA inhibits cyclooxygenase activity, its inhibition of M phi activation was not reversed with the following cyclooxygenase products: PGE2, a stable TXA2 analog (U-46, 619) or a stable PGI2 analog (Iloprost) . Although DHA is metabolized by lipoxygenases, the inhibition was not reversed by the lipoxygenase inhibitors 5, 8, 11, 14-eicosatetraynoic acid and nordihydroguaiaretic acid . Altogether, the data indicate that DHA, at concentrations present in fetal and neonatal sera, inhibits M phi activation and may contribute to the previously observed deficits in M phi function in the fetus and neonate.

Conn Med, 1990 Jun, 54(6), 303 - 4
Incidence of listeriosis in Connecticut; Tosca ML et al.; In Connecticut, 92 cases of human listeriosis were reported to the Department of Health Services from 1984 to 1988 . The annual incidence per million population ranged from 7.3 in 1984 to 4.2 in 1988 . The average annual incidence was 5.6 per million population . Case rates were highest in those aged 70 years and older (15.8 per million) . Cases included 12 pregnant women and 11 newborns . Bacterial meningitis was the primary diagnosis in 23 cases . Of the 49 isolates of Listeria monocytogenes that were serotyped, 21 (43%) were type 4, 24 (49%) were type 1, and 4 (8%) were nontypable.

J Gen Microbiol, 1990 Jun, 136 ( Pt 6), 997 - 100
Listericidal activity of human neutrophil cathepsin G; Alford CE et al.; We demonstrate that cathepsin G, derived from human neutrophils, exhibits potent in vitro antimicrobial activity against Listeria monocytogenes . Cathepsin G listericidal activity was by a non-enzymic mechanism and was dependent on the cationic nature of the molecule . The listericidal activity of cathepsin G occurred in a manner that was both time-dependent and concentration-dependent.

J Dairy Sci, 1990 Jun, 73(6), 1429 - 38
Behavior of Listeria monocytogenes in the presence of gluconic acid and during preparation of cottage cheese curd using gluconic acid; el-Shenawy MA et al.; Unrestricted or minimally restricted growth of Listeria monocytogenes strain V7 occurred 1) at 13 degrees C in tryptose broth with .125 or .25% gluconic acid or .1 to .3% glucono-delta-lactone, 2) at 13 degrees C in milk with .125 to 1.0% gluconic acid or .5 or 1.0% glucono-delta-lactone, 3) at 35 degrees C in tryptose broth with .125 to .5% gluconic acid or .1 to 5% glucono-delta-lactone, and 4) at 35 degrees C in milk with .125 to 1.0% gluconic acid or .5 to 1.5% glucono-delta-lactone . Limited growth of L . monocytogenes occurred 1) at 13 degrees C with .375 or .5% gluconic acid or .3 or .4% glucono-delta-lactone, 2) at 13 degrees C in milk with 1.5% glucono-delta-lactone, 3) at 35 degrees C in tryptose broth with .75% glucono-delta-lactone, and 4) at 35 degrees C in milk with 2.0% glucono-delta-lactone . Partial to complete inactivation of L . monocytogenes occurred 1) at 13 degrees C in tryptose broth with .75 to 1.5% gluconic acid or .75 or 1.0% glucono-delta-lactone, 2) at 13 degrees C in milk with 1.5% gluconic acid or 2.0 to 3.0% glucono-delta-lactone, 3) at 35 degrees C in tryptose broth with .75 to 1.5% gluconic acid or 1.0% glucono-delta-lactone, and 4) at 35 degrees C in milk with 1.5% gluconic acid or 2.5 or 3.0% glucono-delta-lactone . Milk containing L . monocytogenes was coagulated with gluconic acid, HCl, or rennet, and cottage cheese curd was prepared . After cooking, numbers of the pathogen in curd or whey from rennet-coagulated milk were reduced by ca . 1.5 and 2.5 orders, respectively . Small numbers of survivors appeared in curd but not in whey of HCl-coagulated milk . No survivors were detected in curd or whey of gluconic acid-coagulated milk.

Appl Environ Microbiol, 1990 Jun, 56(6), 1897 - 904
Monoclonal antibody specific for Listeria monocytogenes, Listeria innocua, and Listeria welshimeri; Siragusa GR et al.; Eight hundred fifty-nine murine hybridomas were produced from eight fusions, and 27 were characterized for secretion of antibodies reactive to Listeria monocytogenes . One monoclonal antibody (MAb), P5C9, reacted with all test strains of L . monocytogenes (31 of 31), L . innocua (3 of 3), and L . welshimeri (1 of 1) but not with any strains of the other four Listeria species or with any of 22 gram-positive or 11 gram-negative species of bacteria when tested in microtiter and dot blot enzyme immunoassays . Of the other 26 antibodies, 20 reacted with either L . monocytogenes Scott A or V7 and with some or all of the other six Listeria species but also cross-reacted with some or all of the non-Listeria bacteria tested . MAb P5C9 is of the immunoglobulin G1 murine subclass . In Western blot (immunoblot) analyses, this MAb reacted with a single antigen with a molecular weight of 18,500, and it is shared in common with all three reactive species, L . monocytogenes, L . innocua, and L . welshimeri . This antigen was extracted with detergent and appeared to be cell bound.

Appl Environ Microbiol, 1990 Jun, 56(6), 1734 - 42
Inhibitory effects of raw carrots on Listeria monocytogenes; Beuchat LR et al.; The survival and growth of two strains of Listeria monocytogenes on raw and cooked carrots stored at 5 and 15 degrees C and in carrot juice media at 30 degrees C were investigated . The influence of shredding, chlorine treatment, and packaging under an atmosphere containing 3% O2 and 97% N2 on the behavior of L . monocytogenes and naturally occurring microflora was determined . Populations of viable L . monocytogenes decreased upon contact with whole and shredded raw carrots but not cooked carrots . Viable populations also decreased in cell suspensions in which raw carrots were dipped . Small populations of L . monocytogenes detected on whole carrots immediately after dipping were essentially nondetectable after 7 days of storage at 5 or 15 degrees C . After a lag of 7 days at 5 degrees C, significant (P less than or equal to 0.05) increases in populations were detected on shredded carrots after 24 days of storage . Carrots stored at 5 or 15 degrees C spoiled before L . monocytogenes grew . Populations of mesophilic aerobes, psychrophiles, and yeasts and molds increased throughout storage at 5 and 15 degrees C . Cutting treatment (whole or shredded carrots), chlorine treatment, and modified-atmosphere packaging had no effect on the survival or growth of L . monocytogenes or naturally occurring microflora . The presence of raw carrot juice in tryptic phosphate broth at a concentration as low as 1% substantially reduced the maximum population of L . monocytogenes reached after 24 h at 30 degrees C . The anti-Listeria effect of carrots was essentially eliminated when the carrots were cooked.(ABSTRACT TRUNCATED AT 250 WORDS)

Appl Environ Microbiol, 1990 Jun, 56(6), 1584 - 7
Effect of prior heat shock on heat resistance of Listeria monocytogenes in meat; Farber JM et al.; The effect of prior heat shock on the thermal resistance of Listeria monocytogenes in meat was investigated . A sausage mix inoculated with approximately 10(7) L . monocytogenes per g was initially subjected to a heat shock temperature of 48 degrees C before being heated at a final test temperature of 62 or 64 degrees C . Although cells heat shocked at 48 degrees C for 30 or 60 min did not show a significant increase in thermotolerance as compared with control cells (non-heat shocked), bacteria heat shocked for 120 min did, showing an average 2.4-fold increase in the D64 degrees C value . Heat-shocked cells shifted to 4 degrees C appeared to maintain their thermotolerance for at least 24 h after heat shock.

Monatsschr Kinderheilkd, 1990 Jun, 138(6), 351 - 3
{Listeria meningoencephalitis in a 2-year-old boy}; von Kalckreuth G et al.; We report the unusual case of a two year old boy with encephalomeningitis caused by Listeria monocytogenes . The patient was hospitalized with the classical signs of severe bacterial meningitis . The microbiological investigations gave proof of Listeria monocytogenes as causative agent 36 hours later . Antibiotic treatment with ampicillin and gentamicin resulted in a prompt improvement of the boy's condition . The boy was discharged four weeks later.

Immunology, 1990 Jun, 70(2), 191 - 6
Relationship between colony-stimulating activity and interferon production during infection; Egan P et al.; Normal mouse spleen, when cultured in vitro for 3 days in the presence of 10(8) heat-killed Listeria monocytogenes organisms, produced colony-stimulating factors (CSF) that were capable of supporting the production of haemopoietic colonies by bone marrow cells in semi-solid agar, or supporting bone marrow proliferation in liquid medium . In contrast, when the spleen cells were prepared from mice that had been infected with Listeria monocytogenes, colony-stimulating activity (CSA) was no longer detectable over a period from Day 3 to Day 17 post-infection . Suppression of CSA was imposed on normal spleen cells when nylon-wool filtered, T-cell enriched spleen cells from infected mice were co-cultured with normal spleen cells . Suppression largely coincided with the production of interferon by whole spleen from infected mice, and when interferon-gamma (IFN-gamma) was neutralized by antibody CSA was again detected . An early IFN-gamma-independent decrease in CSA production was also detected 2-3 days post-infection . The relevance of this system to the control of CSF production in vivo is discussed.

Infect Immun, 1990 Jun, 58(6), 1943 - 50
The gene coding for protein p60 of Listeria monocytogenes and its use as a specific probe for Listeria monocytogenes; Kohler S et al.; The gene of Listeria monocytogenes that encodes a major extracellular protein (p60) was cloned in Escherichia coli . The gene was designated iap, as p60 was previously shown to represent an invasion-associated protein (M . Kuhn and W . Goebel, Infect . Immun . 57:55-61, 1989) . The recombinant E . coli clone expressed p60, as shown by immunoblotting . The complete nucleotide sequence of iap was determined . The deduced amino acid sequence of p60 (484 amino acids) contains a putative N-terminal signal sequence of 27 amino acids and an extended repeat region consisting of 19 threonine-asparagine units . Hybridization with the entire iap gene revealed the presence of homologous sequences in most other Listeria species . In contrast, a 400-base-pair internal iap probe which contained the whole repeat region hybridized only with genomic DNA from L . monocytogenes . Four oligonucleotides previously described as specific probes for the detection of L . monocytogenes (A . R . Datta, B . A . Wentz, D . Shook, and M . W . Trucksess, Appl . Environ . Microbiol . 54:2933-2937, 1988) were shown to be part of the iap gene.

J Rheumatol, 1990 May, 17(5), 705 - 7
Listeria monocytogenes--an unusual cause of late infection in a prosthetic hip joint; Weiler PJ et al.; As the scope of patients having arthroplasty with compromised immune systems expands, the incidence of late prosthetic infections will increase and the variety of infecting organisms will broaden . The role of prophylactic antibiotics for such patients undergoing procedures known to cause a transient bacteremia is currently unknown . Their use is not universal and many patients undergo procedures frequently without any form of protection . The following case report outlines an unusual organism causing late hip arthroplasty infection in an immunocompromised host and examines the role of prophylactic antibiotics in preventing such complications.

J Clin Periodontol, 1990 May, 17(5), 292 - 7
Efficacy of Listerine, Meridol and chlorhexidine mouthrinses on plaque, gingivitis and plaque bacteria vitality; Brecx M et al.; The experimental gingivitis model was used to compare the anti-plaque, anti-gingivitis and anti-microbial efficacies of a phenolic compound (Listerine) and an amine/stannous fluoride mouthwash (Meridol), using a placebo preparation as negative control and a chlorhexidine solution as positive control in a double-blind study . After professional toothcleaning, 36 volunteers performed optimal oral hygiene for a period of 2 weeks . They then ceased all oral hygiene procedures for 21 days during which they rinsed twice daily with 1 of the 4 mouthrinses . After 3 weeks of rinsing, plaque indices remained the lowest in the chlorhexidine group, while subjects using Listerine or Meridol harbored similar indices significantly lower than that of individuals rinsing with the placebo solution . Up to that time, the gingival index scores were equal in all groups except for the chlorhexidine group in which the values only amounted to half of these encountered in the other groups . The plaque vitality scores showed a bactericidal effect in vivo of chlorhexidine during the entire time of experimental gingivitis . In contrast, the data gave no evidence of an antibacterial effect in vivo of Listerine . The efficacy of Meridol to kill micro-organisms was similar to chlorhexidine during the early stages of plaque accumulation and, with time, became insignificant . This study has demonstrated that chlorhexidine was superior to Listerine and Meridol in its ability to maintain low plaque scores and gingival health during this 3-week period of no mechanical oral hygiene . Moreover, it was also shown that Meridol was as effective as Listerine in reducing plaque accumulation and, in contrast to Listerine, possessed a remarkable but transient antibacterial effect in vivo.

J Infect, 1990 May, 20(3), 251 - 9
Human listeriosis in Denmark 1981-1987 including an outbreak November 1985-March 1987; Samuelsson S et al.; Clinical manifestations, predisposing factors and outcome of listeriosis in Denmark during the period 1981-1987 are described . An increased incidence of the disease during the period November 1985-March 1987 was due mainly to 35 patients infected with strains of Listeria monocytogenes indistinguishable by phage-typing . These patients were younger, previously healthier and had a better prognosis . Also, there were more cases in pregnant women and neonates than in other persons . A strong correlation was found between predisposing factors and mortality . We conclude that there was an outbreak caused by a single source of infection and which was distributed all over the country . It lasted for more than a year and affected most categories of people . The source was not identified.

Ann Pediatr (Paris), 1990 May, 37(5), 299 - 302
{A cerebral abscess due to Listeria monocytogenes in a 15-month-old infant}; Mancini J et al.; We report a case of brain abscess due to Listeria monocytogenes in an infant . We recall that listeriosis is infrequent in pediatric patients beyond the neonatal period, that most cases occur in immunocompromised hosts, and that clinical features are non-specific in neuromeningeal forms . Management of brain abscesses is discussed . The role of the patient's general health condition seems to have a determinant influence on prognosis.

Int J Food Microbiol, 1990 May, 10(3-4), 255 - 62
The occurrence of Listeria monocytogenes in cheese from a manufacturer associated with a case of listeriosis; McLauchlin J et al.; A case of listeriosis was associated with the consumption of a soft cheese produced in England . Goats cheese and other products from the same food manufacturer were examined for the presence of Listeria over the following 11 months . Listeria monocytogenes was isolated from 16 of 25 cheese samples on retail sale, 12 of 24 cheese samples obtained directly from the factory, and from shelving within the plant . Phage-typing of 68 isolates of L . monocytogenes from cheese samples and the factory showed that 66 (97%) were indistinguishable from the strain isolated from the patient's cerebrospinal fluid and stool . L . monocytogenes was not isolated from seven goats milk or two yoghurt samples . Listeria innocua was isolated from 10 cheese samples, two of which contained no other species of Listeria . Levels of L . monocytogenes shortly after production were low (less than 10/g), but were higher (10(5)-10(7) cfu/g) in six of the 16 cheese samples obtained from retail outlets . Multiplication of L . monocytogenes was demonstrated in cheeses contaminated at the factory and held at 4 degrees C in the laboratory.

J Antimicrob Chemother, 1990 May, 25(5), 751 - 8
Participation of PBP 3 in the acquisition of dicloxacillin resistance in Listeria monocytogenes; Gutkind GO et al.; Purified membranes of Listeria monocytogenes ATCC 15313 contain at least five penicillin-binding proteins . In two dicloxacillin-resistant mutants, derived from a sensitive parent strain, a 16-fold increase in the MIC of dicloxacillin was observed . A less-significant increase was detected in the MICs of other beta-lactam drugs . In the mutants, PBP 3 lost its strong affinity for dicloxacillin, but remained fully susceptible to binding of 125I-penicillin X, as compared with the wild-type strain . PBP 2 could not be detected in one of the mutants . No decrease in affinity for the radioactive tracer or dicloxacillin was detected in any other PBP of the resistant mutants.

Rev Infect Dis, 1990 May-Jun, 12 Suppl 4, S410 - 20
Basis and implications of selectively diminished cytokine production in neonatal susceptibility to infection; Wilson CB et al.; The human neonate is unduly susceptible to infection with viruses and other pathogens, such as Toxoplasma and Listeria, that survive and replicate within cells . Cellular immunity is the major mechanism of host defense against these intracellular pathogens . Selective immaturity in certain functions of T lymphocytes appears to be a major factor in the neonate's susceptibility to these infections . Particularly striking is the deficiency in production of interferon-gamma . We review the data regarding the deficiency in the production of interferon-gamma by cells of healthy and infected neonates, discuss what is known regarding the cellular and molecular mechanisms for this deficiency, and review the unique role played by interferon-gamma in host defense against intracellular pathogens . The response of the neonate's effector cells to the immunoenhancing effects of interferon-gamma appears to be variable; diminished enhancement by interferon-gamma of cytotoxic cell function and the production of tumor necrosis factor by macrophages may further compound the effects of diminished production of interferon-gamma.

J Infect, 1990 May, 20(3), 241 - 50
Human listeriosis in Scotland 1967-1988; Campbell DM; In order to study the epidemiology of listeriosis from 1967-1988 in Scotland, various sources of data were examined . These included reports by laboratories, reference laboratory records, hospital death and discharge records, death certificates and hospital laboratory records . Cases were reported from 13 of Scotland's 15 Health Boards . Case ascertainment via laboratory reports to the Communicable Diseases (Scotland) Unit was validated in two Health Boards . A total of 198 cases was identified with an overall attack rate which increased from 0.5 per million in 1967-1971 to 7.0 per million in 1987-1988 . Feto-maternal cases were the commonest (64%) . Of all cases, 33% were neonates; 53% presented with bacteraemia and 41% with meningitis . The predominant serovar of Listeria monocytogenes was 4b.

Appl Environ Microbiol, 1990 May, 56(5), 1216 - 20
Pathogenicity of Listeria monocytogenes grown on crabmeat; Brackett RE et al.; The pathogenicity of Listeria monocytogenes as influenced by growth on crabmeat at 5 and 10 degrees C was studied . Crabmeat was inoculated with L . monocytogenes V7 (ca . 10(4) CFU/g) and incubated for up to 14 days at 5 and 10 degrees C . At selected incubation times, L . monocytogenes was removed from crabmeat by washing with 0.1 M potassium phosphate buffer (pH 7.0), and populations were determined by surface plating on LiCl-phenylethanol-moxalactam agar . Buffered suspensions were then centrifuged, and the resulting pellets were suspended in phosphate buffer containing 10% glycerol and stored at -18 degrees C . Thawed, diluted suspensions of cells were tested for pathogenicity by intraperitoneal injection into immunocompromised and nonimmunocompromised mice . L . monocytogenes cells recovered from crabmeat and then recultured in tryptose phosphate broth (TPB), as well as cells which had not been passed through crabmeat but had been cultured in TPB, were likewise harvested, suspended in buffered 10% glycerol, frozen, thawed, diluted, and tested for pathogenicity by intraperitoneal injection . Growth on crabmeat at 5 and 10 degrees C did not have a significant effect on pathogenicity . The population of L . monocytogenes necessary to kill about 50% of the immunocompromised mice in each test set within 7 days was about 10(4) CFU, and this result was not significantly affected by storage temperature of the crabmeat or type of substrate, i.e., crabmeat or TPB, on which it had grown.

Infect Immun, 1990 May, 58(5), 1254 - 60
Difference in the induction of macrophage interleukin-1 production between viable and killed cells of Listeria monocytogenes; Mitsuyama M et al.; T-cell-mediated immunity to Listeria monocytogenes in mice, as determined by delayed-type hypersensitivity and acquired resistance, was induced by immunization with viable bacteria but not with killed bacteria, even when killed cells were injected in a high dose or repeatedly . T cells obtained from mice immunized with viable L . monocytogenes were readily stimulated with killed-bacterial antigens, resulting in T-cell proliferation in vitro and expression of a delayed footpad reaction in vivo . After immunization with killed-bacterial vaccine, T-cell responsiveness to interleukin 2 (IL-2) never developed but a lower level of responsiveness to IL-1 appeared later than with T cells from mice immunized with viable bacteria . When IL-1 production by macrophages was examined in vitro, viable L . monocytogenes stimulated a high level of IL-1 release while killed bacteria did not . Avirulent strains which were ineffective in the induction of T-cell mediated immunity were incapable of inducing IL-1 production as well . The impaired ability of killed bacteria to stimulate IL-1 production was confirmed by the level of IL-1 mRNA expression . These results suggested that the ineffectiveness of killed L . monocytogenes vaccine is not due to loss or lack of antigenic epitopes but may be ascribed to insufficient induction of IL-1 production in the initial stage of the immune response in vivo.

Cornea, 1990 Apr, 9(2), 179 - 80
Endogenous Listeria monocytogenes endophthalmitis presenting as keratouveitis; Heidemann DG et al.; We report a case of Listeria monocytogenes endophthalmitis that presented as a recalcitrant keratouveitis in a nonimmunocompromized patient . L . monocytogenes was recovered from the patient's aqueous, vitreous, and two of three blood cultures . He was treated with topical, subconjunctival, and systemic antibiotics, but the visual outcome was poor, possibly because of late diagnosis . A review of previous cases of L . monocytogenes endophthalmitis demonstrates unique features of this infection: (a) presentation as an anterior uveitis or keratouveitis with elevated intraocular pressure, (b) endogenous origin, and (c) frequent occurrence in nonimmunocompromized patients.

J Leukoc Biol, 1990 Apr, 47(4), 344 - 54
Physiologic oxygen tensions limit oxidant-mediated killing of schistosome eggs by inflammatory cells and isolated granulomas; Feldman GM et al.; Explanted hepatic granulomas, eosinophils obtained from the peritoneal cavity of schistosome-infected mice, schistosome egg granuloma macrophages, alveolar macrophages, and activated peritoneal macrophages obtained from Listeria-infected mice were miracidicidal when cultured at 21% oxygen . This activity was markedly attenuated at physiologic oxygen concentrations (1-15%) . Catalase and superoxide dismutase blocked the miracidicidal activity of inflammatory cells but did not prevent granuloma-mediated egg killing . However, the biomimetic superoxide dismutase, copper (II) {diisopropyl salicylate}2, inhibited granuloma-mediated egg killing in a dose-dependent, apparently nontoxic manner . Thioglycollate-elicited macrophages did not kill schistosome egg miracidia even when cultured in 21% oxygen, unless pretreated with lipopolysaccharide . Isolated schistosome eggs initiated an oxidative burst in macrophages, as measured by superoxide anion production . This burst was suppressed at reduced oxygen concentrations . Thus schistosome egg miracidia can be killed nonspecifically by macrophages through the release of cytotoxic reactive oxygen intermediates triggered by the egg . This activity is not supported by the oxygen concentrations found in most tissues, with the possible exception of the lung . Schistosoma mansoni eggs, injected intraveneously and lodged in the pulmonary vasculature of mice, were killed rapidly, with a half life of 3.5 days . Eggs, injected into the mesenteric veins and lodged in the liver, remained fully viable for several weeks . The data suggest that the high oxygen tension of the lung allows for the increased production of reactive oxygen intermediates (ROI) by local inflammatory cells, which in turn increases their miracidicidal efficiency . Conversely, the relatively hypoxic environment of the liver decreases ROI production by local inflammatory cells and decreases their miracidicidal efficiency.

Immun Infekt, 1990 Apr, 18(2), 35 - 9
{Listeria--a challenge for diagnosis}; Hof H; The isolation of Listeria spp . from polymicrobially contaminated materials from the environment of human beings is rather difficult . Suppression of the concomitant bacterial flora requires selective growth conditions . Different recipes have been reported to achieve this goal, whereby various antibiotics, among which cephalosporins and nalidixic acid, and dyes, such as acriflavin, have been proposed as supplements to suppress gram-positive as well as gram-negative bacteria . Cycloheximide may help to stop the growth of molds . The diversity of recommendations indicates, however, that an optimal selective medium has not yet been found . A possibility for selective enrichment is the cultivation in the cold, i.e . at +4 degrees C . In the future, genetic as well as immunologic methods will ameliorate the detection of Listeria spp . in environmental specimen . Actually, the offered test assays are still too insensitive so that they need a preceding enrichment process . The isolation of Listeria spp . from specimen of patients when they are present in pure culture is rather easy since these bacteria are not fastidious, so that they grow on the commonly used culture media . Sometimes it is difficult to differentiate Listeria spp . from other gram-positive rods . For the sake of the evaluation of a cultural result it is advisable to characterize further the isolate by simple biochemical tests, since the seven known Listeria spp . among the genus Listeria differ quite definitely from each other in respect to their pathogenic potency . Only bacteria belonging to Listeria monocytogenes represent a potential risk for human health.

Appl Environ Microbiol, 1990 Apr, 56(4), 1164 - 5
Simplified Henry technique for initial recognition of Listeria colonies; Lachica RV; The Henry oblique transmitted-light viewing technique was modified to provide a more precise, convenient, and familiar manner with which to read (score) and recognize colonies of listeriae by their distinct bluish cast . The simplified technique involved illuminating each colony directly with a high-intensity lamp while viewing it with a hand lens at a precise angle in place of a scanning light microscope.

Toxicol Appl Pharmacol, 1990 Apr, 103(2), 198 - 205
Effects of exposure to benzene in vivo on the murine mononuclear phagocyte system; Klan MJ et al.; Exposure to benzene has been shown to decrease resistance to challenges by Listeria monocytogenes or tumor cells in mice . Alterations of T-lymphocytes have been suggested as one probable cause . Macrophages are also critical participants in resistance to Listeria and to tumor cells . We have previously shown that exposure of macrophages in vitro to benzene metabolites, but not to benzene, inhibited several functions of macrophages that are critical for host resistance . The present studies were conducted to determine the effects of exposure to benzene in vivo on the murine mononuclear phagocyte system . Treated animals received daily subcutaneous injections of benzene (800 mg/kg) for 5 days . Macrophages were obtained by lavage from the peritoneal cavity after ip injection of sterile eliciting agents . Enumeration, peroxidase histochemistry, and a series of functional assays were performed . Animals exposed to benzene displayed a decreased number of macrophages elicited by peptone injection . Specific alterations of macrophage functions included a 50% decrease of Fc-receptor-mediated phagocytosis and 70% inhibition of tumor cell cytolysis but an enhancement of TPA-stimulated H2O2 release . There was no effect on interferon-gamma stimulated expression of Ia antigen . The observations that the elicited macrophage populations were composed of newly immigrated cells and that benzene treatment was terminated 3 days before the functional analyses were performed suggest that benzene was affecting monocytes in the blood and precursor cells in the bone marrow . Alterations of macrophage functions in injection controls suggested that determining the primary effect of exposure to benzene may be complicated by the inflammation induced by treatment at the site of injection.(ABSTRACT TRUNCATED AT 250 WORDS)

J Antimicrob Chemother, 1990 Apr, 25(4), 561 - 6
In-vitro synergy testing of nine antimicrobial combinations against Listeria monocytogenes; MacGowan AP et al.; In-vitro antimicrobial synergy against Listeria monocytogenes was assessed using nine combinations in chequerboard (bacteriostatic) tests and time-kill (bactericidal) studies . Ampicillin/gentamicin and trimethoprim/sulphamethoxazole were the most synergistic combinations in bacteristatic tests, whereas gentamicin with ampicillin, trimethoprim or vancomycin and trimethoprim/sulphamethoxazole were the most synergistic in bactericidal tests . Gentamicin-containing combinations were most effective at killing L . monocytogenes and those containing rifampicin least effective.

J Dairy Sci, 1990 Apr, 73(4), 912 - 28
Listeria monocytogenes--threat to a safe food supply: a review; Pearson LJ et al.; Listeria monocytogenes can cause circling disease, encephalitis, meningitis, septicemia, and mastitis in dairy cattle . Shedding of the pathogen from the udder or contamination from the environment can lead to presence of L . monocytogenes in raw milk . Surveys indicate the pathogen is in about 4% of US raw milks . Although HTST pasteurization commonly inactivates L . monocytogenes, evidence suggests that under unusual circumstances minimal survival is possible . The pathogen grows well in liquid dairy products at 4 to 35 degrees C and achieves higher populations in chocolate than in unflavored milks . When present in cheese milk, growth of L . monocytogenes may be retarded but not stopped by lactic starter cultures . The pathogen is concentrated in the curd with only a small fraction of cells in milk appearing in whey . Once in curd, the behavior of the pathogen ranges from growth (feta cheese making) to death of most but not all cells (cottage cheese making) . During ripening of cheese, the numbers of L . monocytogenes decrease gradually (as in Cheddar or Colby cheese), decrease precipitously early during ripening, and then stabilize (as in blue cheese) or increase markedly (as in Camembert cheese) . Consumption of foods containing L . monocytogenes can lead to listeriosis in susceptible humans (adults with a compromised immune system), pregnant women, and infants) . In large outbreaks of human listeriosis, mortality rates of ca . 30% are common.

Antimicrob Agents Chemother, 1990 Apr, 34(4), 539 - 42
Penicillin-binding protein 3 of Listeria monocytogenes as the primary lethal target for beta-lactams; Vicente MF et al.; Penicillin-binding proteins (PBPs) of Listeria monocytogenes were detected by their ability to bind to {2,3-3H}benzylpenicillin . Five proteins with Mrs of 95,000, 84,000, 80,000, 76,000, and 49,000 were detected . PBPs 1 to 4 had a high affinity for {2,3-3H}benzylpenicillin and were relatively scarce (80 to 150 molecules per cell) . In contrast, PBP 5 was more abundant (600 molecules per cell) but had a low affinity for {2,3-3H}benzylpenicillin . L . monocytogenes has a relatively high natural resistance to cephalosporins . Competition experiments showed that cephalosporins bound very poorly to PBP 3 but were good inhibitors of PBPs 1, 2, and 4, which were completely blocked at concentrations well below the MIC . Analysis of a spontaneous imipenem-resistant mutant revealed that resistance was likely due to an altered PBP 3 with a reduced affinity for {2,3-3H}benzylpenicillin . These results suggest that PBP 3 is a primary lethal target for beta-lactams in L . monocytogenes.

Appl Environ Microbiol, 1990 Apr, 56(4), 1166 - 8
Same-day identification scheme for colonies of Listeria monocytogenes; Lachica RV; A diagnostic scheme is described for the same-day identification of food-borne cells of Listeria monocytogenes that emerge in 40 h at 30 degrees C as large colonies, representatives of which are used to advantage as heavy inocula on agar plates for the rapid determination of hemolytic activity and acidification of rhamnose and xylose . Additional tests consisting of phase-contrast microscopy for cell morphology and motility, the catalase production test, and the KOH viscosity test in place of Gram staining complete the rapid identification scheme.

J Exp Med, 1990 Apr 1, 171(4), 1141 - 54
Roles of CD4+ and CD8+ cells, and the effect of administration of recombinant murine interferon gamma in listerial infection; Sasaki T et al.; Studies were made on the effects of in vivo administration of anti-CD4 mAb, anti-CD8 mAb, or a combination of both mAbs on multiplication of bacteria, the levels of serum transaminases, and mortality in mice infected with Listeria monocytogenes . Results showed that in sublethal infection, CD8+ cells enhanced the peak of bacterial multiplication and liver cell necrosis, and CD4+ cells suppressed CD8+ cell-mediated enhancement . Results also showed that either CD4+ or CD8+ cells were necessary for, and capable of, mediating clearance of the bacteria . CD8+ cells were more efficient than CD4+ cells, but for optimal clearance both were necessary . In lethal listeriosis, treatment of mice with anti-CD8 mAb or a combination of both anti-CD4 and anti-CD8 mAbs, but not anti-CD4 mAb only, protected mice from death by decreasing multiplication of bacteria in the liver and spleen after a peak of approximately 10(8) CFU, and lowering the elevated serum levels of transaminases . These findings indicated that CD8+ cells were responsible for causing irreversible systemic Listeria infection and severe liver necrosis . In lethal listeriosis, administration of rMuIFN-gamma markedly prolonged survival by decreasing multiplication of bacteria and promoting recovery from liver necrosis.

Epidemiol Infect, 1990 Apr, 104(2), 191 - 201
Human listeriosis in Britain, 1967-85, a summary of 722 cases . 2 . Listeriosis in non-pregnant individuals, a changing pattern of infection and seasonal incidence; McLauchlin J; Clinical information was collected on 722 cases of Listeria monocytogenes infections in humans occurring in Britain between 1967 and 1985 . This series comprised 34% (248 cases) associated with pregnancy and 66% (474 cases) in non-pregnant adults and juveniles . The cases not associated with pregnancy comprised: 76% in patients with severe underlying illness (of which 34% had central nervous system infections, and 42% bacteraemia without involvement of the central nervous system); 21% in previously healthy individuals (of whom 18% had meningitis); and 3% in patients without bacteraemia or involvement of the central nervous system . Cases occurred most often in male patients over 40 years of age . The overall mortality was 44% . Overall, the pattern of infection has altered to a disease of higher incidence, affecting most often susceptible non-pregnant individuals and the unborn . An annual increase in incidence of listeriosis occurred in the autumn in all categories of patients.

Epidemiol Infect, 1990 Apr, 104(2), 181 - 9
Human listeriosis in Britain, 1967-85, a summary of 722 cases . 1 . Listeriosis during pregnancy and in the newborn; McLauchlin J; Clinical information was collected on 722 cases of Listeria monocytogenes infections in humans occurring in Britain between 1967 and 1985: 248 cases (34%) were associated with pregnancy (maternal, foetal, and neonatal), and comprised 9 cases (4%) of maternal bacteraemia without infection of the foetus; 42 cases (19%) of intra-uterine deaths; 118 cases (54%) of neonatal infection diagnosed within 2 days post-partum; and 50 cases (23%) of neonatal infection diagnosed as ill after 2 days post-partum . An overall mortality of 50% was recorded . The cases unassociated with pregnancy are described elsewhere (see accompanying paper).

Infect Immun, 1990 Apr, 58(4), 1048 - 58
Intracellular and cell-to-cell spread of Listeria monocytogenes involves interaction with F-actin in the enterocytelike cell line Caco-2; Mounier J et al.; Listeria monocytogenes penetrates and multiplies within professional phagocytes and other cells such as the Caco-2 human enterocytelike cell line . Listeriolysin O, a membrane-damaging cytotoxin accounts for intracellular multiplication through lysis of the membrane-bound phagocytic vacuole . This work demonstrates that once released within the cytosol, L . monocytogenes acquires the capacity to spread intracellularly and infect adjacent cells by interacting with host cell microfilaments . Such evidence was obtained by using drugs which disrupt the cell cytoskeleton . Nocodazole, which blocks polymerization of microtubules, did not affect intracellular spread, whereas cytochalasin D, which blocks polymerization of G-actin, inhibited the intracellular motility of the bacteria . By using fluorescence staining with 7-nitrobenz-2-oxa-1,3-diazole-phallacidin (NBD-phallacidin), transmission electron microscopy, and immunogold labeling, direct evidence was obtained that intracellular bacteria were enveloped with a thick layer of F-actin . Within 2 h after entry, it was demonstrated by confocal microscopy that bacteria were following highly organized routes corresponding to stress fibers . Four hours after entry, some bacteria presented random movements which could be seen by the presence of a large trail of F-actin . Such movements also caused protrusions which deeply penetrated adjacent cells and resulted in the formation of vacuoles limited by a double membrane . After subsequent lysis of these membranes, bacteria released within the cytoplasm were able to multiply and invade new cells . In contrast, an hly::Tn1545 mutant of the wild-type microorganism demonstrated almost no intracellular spread . Only a few bacteria displaying delayed lysis of the phagocytic vacuole behaved like the wild-type strain . Hemolysin-mediated lysis of the phagocytic vacuole and subsequent interaction with host cell microfilaments may represent a major virulence factor allowing tissue colonization during listeriosis.

Lett Appl Microbiol, 1990 Apr, 10(4), 179 - 81
Development of an optimized system for electroporation of Listeria species; Alexander JE et al.; Electroporation was used to facilitate transformation of Listeria species with plasmid DNA . Optimal conditions for transformation of L . monocytogenes were a field strength of 8.5 kV/cm, 200 Ohms resistance, 25 microF capacitor with a time constant of 5 ms . With these conditions, 3.9 x 10(6) transformants/micrograms DNA were obtained . Under the same conditions, L . innocua and L . ivanovii exhibited a frequency of transformation similar to that of L . monocytogenes but a somewhat lower level was obtained with L . seeligeri.

Lancet, 1990 Mar 17, 335(8690), 624 - 7
Detection of anti-listeriolysin O for serodiagnosis of human listeriosis; Berche P et al.; To see whether detection of antibodies against listeriolysin O (LLO) could be used to diagnose human listeriosis, sera from 28 patients infected with Listeria monocytogenes and 101 controls were tested by dot-blot titration with purified LLO . 27 patients (96.4%) with listeriosis produced specific anti-LLO . Anti-LLO was detected in 8 (15.6%) of 51 healthy controls and in 6 (12.0%) of 50 controls who had various bacterial, fungal, and viral infections . Anti-LLO titres did not exceed 100 in these two control groups . Anti-LLO could be detected soon after clinical onset of listeriosis, and antibodies persisted for at least several months . This test might be useful for epidemiological surveys and for serodiagnosis of listeriosis, especially when bacteria cannot be isolated.

J Immunol, 1990 Mar 15, 144(6), 2179 - 83
IL-1 beta is secreted by activated murine macrophages as biologically inactive precursor; Beuscher HU et al.; IL-1 alpha and IL-beta are distinct cytokines, produced by activated macrophages . The temporal sequence in the processing and secretion as well as the mechanism(s) by which IL-1 is secreted from the cells remain undefined . Here we have studied the production of IL-1 from murine macrophages after stimulation with LPS or Listeria monocytogenes by two distinct methods: i) immunoprecipitation of radio-labeled IL-1 peptides from culture supernatants, and ii) determination of IL-1 activity by neutralization with monospecific antisera to either form of IL-1 . We confirmed that precursor and mature forms of both IL-1 alpha and IL-1 beta can be detected in the culture supernatants after stimulation of the macrophages with 10 to 20 micrograms LPS/ml but, in addition, we report the novel finding that IL-1 beta is exclusively secreted in its unprocessed precursor form after stimulation of the cells with either 0.5 to 1 microgram LPS/ml or with L . monocytogenes . Exposure of the cells to increasing amounts of LPS led to the appearance of a 20-kDa IL-1 beta peptide in the culture supernatants concomitant with the release of a processing activity for the IL-1 beta precursor . These data therefore suggest that, in a first step, IL-1 beta is secreted as an unprocessed precursor protein that in a second, postsecretory step is cleaved by a LPS-inducible protease, thus generating the 20-kDa IL-1 beta peptide . The latter represents the biologically active IL-1 beta inasmuch as the generation of IL-1 beta activity in the culture supernatants strictly correlated with the appearance of the 20-kDa IL-1 beta peptide.

Am J Ophthalmol, 1990 Mar 15, 109(3), 334 - 9
Listeria monocytogenes keratitis; Zaidman GW et al.; We treated a farmer who had Listeria monocytogenes bacterial keratitis . Therapy with topical antibiotics was unsuccessful; it was necessary to treat the patient with topical and systemic penicillin and gentamicin . To elucidate the pathogenesis of this infection, we developed a rabbit model . Using the patient's strain of L . monocytogenes, we determined that the severity of the rabbit infection was dose-related . If we used an inoculum of more than 10(7) organisms, many of the features of the human Listeria keratitis were mimicked . We also found that treatment with either penicillin or gentamicin did not control the infection as well as using both antibiotics simultaneously, a combination which resulted in relatively rapid resolution of infection and no corneal scarring . The human and animal data indicate that L . monocytogenes can be a virulent corneal pathogen . Listeria corneal infections must be treated aggressively with both penicillin and gentamicin to prevent permanent visual loss.

FEMS Microbiol Lett, 1990 Mar 15, 56(3), 301 - 5
Surface Listeria monocytogenes carbohydrate-binding components revealed by agglutination with neoglycoproteins; Cottin J et al.; Carbohydrate-binding components were shown to be present at the surface of Listeria monocytogenes by means of a panel of neoglycoproteins using direct agglutination . These lectin-like components bind on neoglycoproteins bearing D-glucosamine, L-fucosylamine, or para-amino-phenyl-alpha-D-mannopyrannoside residues . The interactions were inhibited by the carbohydrate moieties specific to the neoglycoproteins . The protein nature of the lectin-like components of L . monocytogenes was ascertained by the loss of carbohydrate-binding capacity following protease treatment.

Postgrad Med J, 1990 Mar, 66(773), 203 - 4
Opportunistic Listeria pericardial effusion; Crellin AM et al.; A case is described of pericardial effusion due to Listeria monocytogenes infection in a woman with advanced carcinoma of the cervix, rheumatoid arthritis and on corticosteroid therapy . Focal infection with listeria in immunocompromised adults has a high mortality unless promptly diagnosed . The correct diagnosis may have been made if an unexplained pericardial effusion had been tapped.

Am J Trop Med Hyg, 1990 Mar, 42(3), 254 - 9
Systemic disease in Peromyscus leucopus associated with Borrelia burgdorferi infection; Burgess EC et al.; Sixteen wild Peromyscus leucopus, trapped for the establishment of a breeding colony, developed signs of neurological damage (trembling, incoordination, circling, head tilt, and lameness of the rear legs) 2-47 days after capture in southern Wisconsin . Spirochetes were cultured from the brain of 5/11 mice, and Borrelia burgdorferi was cultured from 1 brain . A spirochete was isolated from the bladder of 1 mouse . The spirochete was identified by fluorescent antibody staining with the monoclonal antibody specific for B . burgdorferi, H5332 . Serum antibodies to the spirochete were found in 14/15 mice . Negative results were obtained in all tests for viruses and bacteria, including Listeria (2/2), Mycoplasma (2/2), mouse hepatitis virus (10/10), Theilers's encephalomyelitis virus (GD VII) (8/8), REO 3 virus (2/2), and lymphocytic choriomeningitis virus (4/4) . There was no bacterial growth from brains cultured on eosin methylene blue or blood agar (3/3) . Histologic lesions included nonsuppurative cellular infiltrates in the brain, kidney, liver, and lung . Three outbred Swiss-Webster mice were inoculated orally with a suspension of the brain in BSKII medium, and 3 were inoculated with unpassed B . burgdorferi cultured from the brain of a P . leucopus with motor dysfunction . Five of the inoculated mice developed antibody titers of 1:128; one mouse was positive at 1:256 . Motor signs of neurologic damage developed in 3/6 mice 2-24 weeks post-inoculation, and B . burgdorferi was detected in the brains of 2 mice by isolation and by fluorescent antibody.

Appl Environ Microbiol, 1990 Mar, 56(3), 657 - 60
Evaluation of the Mast ID and API 50CH systems for identification of Listeria spp; Kerr KG et al.; A multipoint inoculation technique (Mast ID) for the identification and species determination of Listeria monocytogenes (sensu strictu) and six other species of the genus Listeria was evaluated . This was compared with the commercially available API 50CH system . Both methods successfully identified all 123 strains tested . The Mast ID system is inexpensive and utilizing a multipoint inoculation technique permits the screening of up to 21 isolates per 9-cm petri dish . The API 50CH system was more expensive and time consuming and is therefore suitable only for the examination of smaller numbers of strains.

Int J Food Microbiol, 1990 Mar, 10(2), 143 - 55
Efficacy of direct plating media for recovering Listeria monocytogenes from foods; Golden DA et al.; Studies were done to evaluate 14 direct plating media for their suitability to recover Listeria monocytogenes strain Scott A from pasteurized whole milk, chocolate ice cream mix, Brie cheese and raw cabbage . Healthy cells were inoculated into foods to achieve viable populations of 10(2), 10(4), or 10(6) cells/ml(g) . Bind's Acriflavine Agar, Trypaflavine Nalidixic Acid Serum Agar, Listeria Transport Enrichment Agar, Doyle and Schoeni Selective Enrichment Agar (DSSEA) and Modified DSSEA were not suitable for recovering L . monocytogenes from milk and Brie cheese and were therefore not evaluated as direct plating media for recovering the organism from ice cream mix and cabbage . McBride Listeria Agar (MLA), Gum Base Nalidixic Acid Tryptone Soya Agar (GBNTSA), Modified Despierres Agar (MDA) and Modified MLA (MMLA) performed best for recovering all inoculum populations from milk and ice cream mix . Enumeration of L . monocytogenes on several test media was complicated by the growth of large numbers of background microflora present in cabbage and Brie cheese, especially at the lowest test inoculum (10(2)/g) . Generally, complete recovery of L . monocytogenes from Brie cheese and cabbage was attained on media when the inoculum population was greater than or equal to 10(4) cells/g . For Brie cheese, MLA, MDA, MMLA and Dominguez Rodriguez Isolation Agar were superior for recovering L . monocytogenes, while GBNTSA, DLEA, MDA and MMLA were best for recovering the organism from cabbage . Results of this experiment indicate that direct-plating procedures, without prior enrichment, can successfully be utilized for recovering L . monocytogenes from foods such as pasteurized milk and ice cream mix which contain low populations of background microflora . However, recovery of L . monocytogenes from foods such as raw cabbage and Brie cheese, which contain high populations of other microorganisms, was not satisfactory using the direct-plating procedures evaluated in this investigation.

Poult Sci, 1990 Mar, 69(3), 457 - 61
Listeria monocytogenes colonization of broiler chickens; Bailey JS et al.; In three trials, a total of 108 broiler chickens were unchallenged or challenged orally with either 10(2) or 10(6) cells of Listeria monocytogenes at 1, 14, or 35 days of age . The birds were kept in separate wire-floored brooders and growout batteries, fed unmedicated broiler-starter rations ad libitum, and killed 7 days postchallenge . The ceca, duodenum, spleen, liver (including gall bladder), and a cloacal swab were sampled from each bird and were analyzed for the presence of L . monocytogenes . In Trial 1, L . monocytogenes was recovered on all sampling days, but most frequently from birds challenged when 1 day old . In Trials 2 and 3, recovery was only from birds challenged at 1 day of age . The L . monocytogenes organism was not recovered from any uninoculated control birds . There was a dose-related colonization response (10(6) greater than 10(2}; and more recoveries were obtained from the ceca, spleen, and cloacal swabs than from the duodenum and liver.

Eur J Clin Microbiol Infect Dis, 1990 Mar, 9(3), 210 - 3
Distribution of serovars of Listeria monocytogenes isolated from different categories of patients with listeriosis; McLauchlin J; An analysis was made of the distribution of serovars of Listeria monocytogenes isolated from 1363 patients with listeriosis . Overall, serovar 4b was found in 64% of cases, serovar 1/2a in 15%, serovar 1/2b in 10%, and serovar 1/2c in 4% . The patients were categorised as pregnancy associated cases, non-pregnant previously healthy cases, and non-pregnant cases with severe underlying illness . The serovars were unequally distributed between these three groups of patients . Serovar 1/2b occurred most often in the non-pregnant cases with severe underlying illness, and serovar 1/2c occurred least frequently in the pregnancy associated cases . Serovar 4b occurred more often in the pregnancy associated cases than in previously healthy non-pregnant cases, and more often in the latter than in those with underlying illness . Similar distributions of the serovars between the categories of patients occurred over different time periods . These results may be interpreted as indicating an association between virulence and serological type of Listeria monocytogenes.

Eur J Clin Microbiol Infect Dis, 1990 Mar, 9(3), 206 - 9
In vitro bactericidal activity of amoxicillin, gentamicin, rifampicin, ciprofloxacin and trimethoprim-sulfamethoxazole alone or in combination against Listeria monocytogenes; Boisivon A et al.; The in vitro bactericidal activity of amoxicillin, gentamicin, rifampicin, ciprofloxacin and trimethoprim-sulfamethoxazole alone or in combination was determined against seven strains of Listeria monocytogenes by the killing curve method . Amoxicillin plus gentamicin was the most rapidly bactericidal combination, whereas trimethoprim-sulfamethoxazole was less bactericidal at 6 h but as bactericidal at 24 h . The combination of trimethoprim-sulfamethoxazole with either amoxicillin, ciprofloxacin or rifampicin did not result in antagonism, but the combinations were no more active than trimethoprim-sulfamethoxazole alone . The interaction of amoxicillin with rifampin was fairly antagonistic (1 log10 difference) . The combination of amoxicillin and ciprofloxacin, although producing antagonism during the first 6 h, was more active at 24 h than amoxicillin alone and prevented the regrowth observed with ciprofloxacin alone . Ciprofloxacin and rifampicin interacted antagonistically during the first 6 h, and the combination was not very bactericidal (3 log10) but prevented the emergence of mutants, as observed with each drug alone, when used at concentrations greater than the MICs for the strain tested . These regimens merit evaluation in in vivo models of Listeria monocytogenes meningitis.

Infection, 1990 Mar-Apr, 18(2), 107 - 8
Recurrent Listeria monocytogenes bacteraemia in a liver transplant patient; Peetermans WE et al.; We report a case of a recurrent Listeria monocytogenes bacteraemia in a 46 year-old liver transplant patient . Serotyping revealed that the two episodes of bacteraemia were caused by different strains . The possibility of a recrudescence of a persisting infection was rejected . We concluded that the recurrent bacteraemia in this predisposed patient was due to re-infection, and that antibiotic treatment (amoxicillin plus an aminoglycoside) resulted in a complete eradication of the infective microorganism . Therefore long-term suppressive antibiotic treatment was not indicated . The source of these L . monocytogenes infections was not found.

Eur J Immunol, 1990 Mar, 20(3), 533 - 8
Sequential appearance of gamma/delta- and alpha/beta-bearing T cells in the peritoneal cavity during an i.p . infection with Listeria monocytogenes; Ohga S et al.; To search for a potential role of T cell antigen receptor (TcR) gamma/delta-bearing cells in host-defense against Listeria monocytogenes, we analyzed the sequential appearance of gamma/delta and alpha/beta T cell in the peritoneal exudate cells (PEC) during an i.p . infection with sublethal dose (2 X 10(3) of viable Listeria organisms in mice . The PEC on day 1 after the infection consisted of 48% macrophages and 50% lymphocytes, most of which were surface IgM+ (B) cells . The number of PEC increased to the maximal level by day 3 . The PEC at this stage contained an appreciable number of CD3+ T cells in addition to a large number of macrophages . Of the CD3+ cells, the proportion of CD4- CD8- cells, most of which expressed no TcR alpha/beta, increased to the maximal level on day 3 after the infection . In correlation with an increased number of CD3+ CD4- CD8- TcR alpha/beta- cells, high level of TcR gamma/delta chain gene messages was detected in the nonadherent population of the PEC on this stage . On the other hand, the PEC on day 8 contained an increased number of CD4+ CD8- and CD4- CD8+ cells which expressed TcR alpha/beta chain on their surface . These results suggest that the gamma/delta T cells precede the alpha/beta T cells in appearance during listerial infection . The gamma/delta T cells may be involved at the first line of the host-defense against Listeria.

Infect Immun, 1990 Mar, 58(3), 654 - 8
Expression of systemic protection and delayed-type hypersensitivity to Listeria monocytogenes is mediated by different T-cell subsets; Baldridge JR et al.; The relationship between acquired cellular resistance and delayed-type hypersensitivity (DTH) during the immune response to Listeria monocytogenes was investigated . Treatment of concanavalin A-stimulated Listeria-immune spleen cells with anti-CD8 antibody plus complement abrogated the adoptive transfer of systemic antilisterial immunity but had no effect on the transfer of DTH . In contrast, in vitro depletion of the CD4+ T-cell subset eliminated the ability of culture-activated cells to transfer DTH reactivity but did not interfere with the adoptive transfer of protection . In vivo, the infusion of anti-CD8 antibody inhibited the expression of both actively and adoptively transferred protection but did not influence the development of DTH skin test reactivity to L . monocytogenes antigens . In vivo depletion of the CD4+ T-cell subset eradicated the DTH response, with only minor influence of the protective anti-Listeria response . The apparent functional dissociation of the CD4+ (DTH) and CD8+ (protection) T-cell populations was further emphasized by our findings that the adoptive transfer of protection was dependent on a cyclophosphamide-sensitive cell population, whereas DTH reactivity was mediated by a cyclophosphamide-resistant population.

J Immunol Methods, 1990 Feb 20, 127(1), 71 - 7
Measurement of macrophage adherence and spreading with weak electric fields; Kowolenko M et al.; A new method to monitor macrophage attachment on protein-coated surfaces and spreading in response to activating agents is described . Murine macrophages were cultured on small gold electrodes coated with protein, and attachment and spreading were detected as electrical impedance changes . The rate of attachment of cells to fibronectin-coated electrodes was measured to be significantly greater than to other proteins tested . Activation agents used included interferon-gamma, lipopolysaccharide and heat killed Listeria monocytogenes . Addition of each agent to macrophages on electrodes resulted in characteristic patterns in the impedance time course with impedance changes as large as 40%.

Infect Immun, 1990 Feb, 58(2), 495 - 501
Induction of antigen-specific immunity and tolerance to Mycobacterium leprae in Lewis rats; Winters MA et al.; Intradermal (i.d.) immunization of Lewis rats with autoclaved Mycobacterium leprae resulted in antigen-specific proliferation responses and interleukin-2 release from spleen and lymph node cells that were detectable as early as 21 days, persisted for at least 9 months, and were dependent on the dose of antigen administered . Immunized animals were also completely resistant to a footpad challenge with viable M . leprae . In contrast, intravenous (i.v.) administration of at least 10(8) irradiated M . leprae isolates induced a state of nonresponsiveness characterized by the absence of proliferation and interleukin-2 release by antigen-stimulated lymphoid cell cultures; however, in vitro responses to mitogenic stimulation and in vivo responses to keyhole limpet hemocyanin and Listeria monocytogenes were normal . Animals that received an i.v . injection of M . leprae remained nonresponsive to M . leprae antigens even after a subsequent i.d . immunization . This state of nonresponsiveness persisted for at least 6 months after induction . Results of footpad challenge experiments showed that the ability of animals rendered nonresponsive by an i.v . injection of M . leprae to control the growth of viable M . leprae in the footpad was not different from that of untreated rats . In addition, animals receiving an initial i.v . injection and a subsequent i.d . immunization with M . leprae were not protected from a viable challenge, as were rats that received only i.d . immunization . These results suggest that i.v . administration of a large dose of M . leprae to rats induces a state of nonresponsiveness to M . leprae antigens that may be similar to that seen in lepromatous leprosy patients.

Microb Pathog, 1990 Feb, 8(2), 143 - 9
Comparative activity of human and murine tumor necrosis factor in toxicity and anti-infectious assays in mice; Parant F et al.; In comparative experiments, the lethal effect of rHuTNF or rMuTNF was evaluated in animals sensitized by adrenalectomy or galactosamine treatment . No clear-cut difference was observed in the effective dose irrespective of the origin of the TNF preparation in Swiss or in C3H/HeJ mice . The latter mouse substrain known to be a low responder to LPS was used in the assays to evaluate the influence of LPS contamination in TNF-induced responses . Like LPS, TNF was shown to induce abortion in pregnant mice, and the mortality rate of foetuses was almost the same in animals challenged with either rHuTNF or rMuTNF . No species preference was apparent in the protective effect of TNF against a bacterial challenge . In adult mice subsequently infected with Klebsiella pneumoniae or Listeria monocytogenes, the survival rate was comparable in groups treated with both TNF preparations . In contrast, in young mice rHuTNF and rMuTNF were ineffective against Listeria and poorly active against Klebsiella organisms, whereas a significant effect was obtained with crude mouse serum containing TNF.

Kansenshogaku Zasshi, 1990 Feb, 64(2), 249 - 56
{Three cases of meningitis due to Listeria monocytogenes type Ib}; Kuroki H et al.; Three infants having Listeria monocytogenes meningitis were admitted to our hospital in the last ten years . They were a nineteen-month-old boy, a two-year-old girl and a five-year-old girl . They were all healthy infants . The two female patients survived, while the male patient died . At autopsy, arachnoid turbid, swollen brain substance and slight bleeding under the cerebellar tent were observed . Judging from the minimal inhibitory concentration of antibiotics against the isolated L . monocytogenes, antibacterial activity of penicillin G and ampicillin was good, whereas that of cefotaxime and latamoxef was poor . In conclusion, for therapy of bacterial meningitis due to unknown origin, the combination of ampicillin and cephalosporins is necessary.

Rev Esp Cardiol, 1990 Feb, 43(2), 123 - 6
{Mitro-aortic endocarditis caused by Listeria monocytogenes}; Ochoteco A et al.; A case of Listeria monocytogenes valvular endocarditis is reported . This patient required mitral and aortic valve replacement by Bjork-Shiley mechanical prostheses . Patient clinical condition was progressively deteriorated, affecting the left ventricular function, increasing the size of vegetations and the presence of aortic annular abscess . This case represents the 48th reported in the literature and the third in our country . We here comment about the clinical aspects and the treatment of this infrequent entity.

J Appl Bacteriol, 1990 Feb, 68(2), 153 - 6
The incidence of Listeria spp . in soft cheeses, butter and raw milk in the province of Bologna; Massa S et al.; Samples of soft cheese, butter and raw milk were examined for Listeria species . Listeria monocytogenes (serotype 1, haemolytic and virulent for mice) and L . innocua (the only other Listeria sp . isolated) were each found in 2/21 (1.6%) of soft cheese samples . Five per cent of butter samples were contaminated with L . innocua . No Listeria spp . were detected in 40 raw milk samples . The results were compared with similar studies in Italy and abroad.

Br J Obstet Gynaecol, 1990 Feb, 97(2), 186 - 9
Listeriosis revisited: the role of the obstetrician; Buchdahl R et al.; The clinical course and outcome is described of three pregnancies complicated by listeriosis encountered during a 6-month period . All three ended in preterm labour characterized by the passage of meconium by the fetus . Two babies died in the early neonatal period and the third survived with neurological handicap . Although the diagnosis of listeriosis was made only after delivery, all the mothers had a pyrexial illness before delivery . A high index of suspicion is needed for the early detection and prompt treatment of this life-threatening perinatal infection . Effective advice concerning prevention of listeriosis by avoidance of high-risk foods must be given to women during pregnancy.

Immunology, 1990 Feb, 69(2), 316 - 22
Human rTNF alpha augments anti-bacterial resistance in mice: potentiation of its effects by recombinant human rIL-1 alpha; Roll JT et al.; Treatment with human recombinant tumour necrosis factor-alpha (rTNF alpha) significantly enhanced resistance to Listeria monocytogenes infection in mice . The level of protection (which was dose-dependent and maximal at approximately 1.0 microgram per mouse) was similar to that previously reported for the monokine rIL-1 alpha, although somewhat greater amounts of rTNF alpha than rIL-1 alpha were required . Combined administration of suboptimal concentrations of rTNF alpha and rIL-1 alpha resulted in significant enhancement of resistance beyond that obtained with either monokine alone, whereas further increases in anti-listeria resistance were not observed at doses of rTNF alpha or IL-1 alpha that were themselves capable of inducing substantial protection . Combined administration of rTNF alpha and rIL-1 alpha was associated with a delay in onset and lessening in severity of the lymphopenia that accompanied L . monocytogenes infection . The reduced bacterial burden in the spleens and livers of mice treated with rTNF alpha and rIL-1 alpha was associated with a more rapid decline in serum colony-stimulating activity . Peritoneal macrophages from rTNF alpha- and rIL-1 alpha-treated listeria-infected mice did not demonstrate enhanced anti-listeria activity in vitro . These results provide further evidence for the potential benefits of rTNF alpha and other cytokines in promoting anti-bacterial resistance . They further suggest that use of combinations of cytokines is a strategy worthy of further consideration.

South Med J, 1990 Feb, 83(2), 213 - 4
Secondary bacterial peritonitis due to Listeria monocytogenes after paracentesis; Siegfried C et al.; Although it is a relatively rare cause of peritonitis, Listeria monocytogenes must be considered in cirrhotic patients with ascites and a suggestive clinical presentation . We believe this is the first report of a case of peritonitis due to L monocytogenes in a patient without sepsis, and the sixth reported case of bacterial peritonitis in a patient with cirrhosis.

J Appl Bacteriol, 1990 Feb, 68(2), 157 - 62
Growth of Listeria monocytogenes at refrigeration temperatures; Walker SJ et al.; The growth of three strains of Listeria monocytogenes at refrigeration temperatures (-0.5 to 9.3 degrees C) in chicken broth and/or UHT milk was determined using a rocking temperature gradient incubator . Minimum growth temperatures ranged from -0.1 to -0.4 degree C for the three strains . Lag times of 1-3 d and 3 to greater than 34 d were observed with incubation at 5 and 0 degrees C respectively . Corresponding generation times ranged from 13-24 h at 5 degrees C and 62-131 h at 0 degree C . The type of culture medium had an influence on both the rate and extent of growth . Incubation of cultures at 4 degrees C before inoculation caused a marked reduction in the lag time when compared with cultures which had been previously incubated at 30 degrees C.

Appl Environ Microbiol, 1990 Feb, 56(2), 377 - 80
Efficacy of a variety of disinfectants against Listeria spp; Best M et al.; The efficacy of 14 disinfectants against Listeria innocua and two strains of Listeria monocytogenes in the presence of organic matter was studied . Quantitative efficacy tests were used . Many of the disinfectants tested were not as effective on Listeria spp . when the test organisms were dried onto the surface of steel disks (carrier tests) as they were when the organisms were placed in suspension (suspension test) . The presence of whole serum and milk (2% fat) further reduced the disinfectant capacities of most of the formulations studied . Only three disinfectants (povidone-iodine, chlorhexidine gluconate, and glutaraldehyde) were effective in the carrier test in the presence of serum; however, all three were ineffective when challenged with milk (2% fat) . Only one solution, sodium dichloroisocyanurate, was effective in the presence of milk . All but four formulations (chloramine-T, phosphoric acid, an iodophor, and formaldehyde) were effective in the suspension tests, regardless of the organic load . L . monocytogenes was observed to be slightly more resistant to disinfection than L . innocua was . There was no difference in disinfectant susceptibility between the two strains of L . monocytogenes . These findings emphasize the need for caution in selecting an appropriate disinfectant for use on contaminated surfaces, particularly in the presence of organic material.

Appl Environ Microbiol, 1990 Feb, 56(2), 370 - 6
Effects of growth temperature and strictly anaerobic recovery on the survival of Listeria monocytogenes during pasteurization; Knabel SJ et al.; Listeria monocytogenes F5069 was suspended in either Trypticase soy broth-0.6% yeast extract (TSBYE) or sterile, whole milk and heated at 62.8 degrees C in sealed thermal death time tubes . Severely heat-injured cells were recovered in TSBYE within sealed thermal death time tubes because of the formation of reduced conditions in the depths of the TSBYE . Also, the use of strictly anaerobic Hungate techniques significantly increased recovery in TSBYE containing 1.5% agar compared with aerobically incubated controls . The exogenous addition of catalase, but not superoxide dismutase, slightly increased the recovery of heat-injured cells in TSBYE containing 1.5% agar incubated aerobically . Growth of cells at 43 degrees C caused a greater increase in heat resistance as compared with cells heat shocked at 43 degrees C or cells grown at lower temperatures . Growth of L . monocytogenes at 43 degrees C and enumeration by the use of strictly anaerobic Hungate techniques resulted in D62.8 degrees C values that were at least sixfold greater than those previously obtained by using cells grown at 37 degrees C and aerobic plating . Results indicate that, under the conditions of the present study, high levels of L . monocytogenes would survive the minimum low-temperature, long-time treatment required by the U.S . Food and Drug Administration for pasteurizing milk . The possible survival of low levels of L . monocytogenes during high-temperature, short-time pasteurization and enumeration of injured cells by recovery on selective media under strictly anaerobic conditions are discussed.

J Immunol, 1990 Feb 1, 144(3), 1052 - 61
Alveolar macrophage function in rats with severe protein calorie malnutrition . Arachidonic acid metabolism, cytokine release, and antimicrobial activity; Skerrett SJ et al.; To investigate the effects of protein calorie malnutrition (PCM) on alveolar macrophage function, we measured antimicrobial activity, IL-1 and TNF production, and arachidonic acid metabolism in alveolar macrophages of infant rats with moderate and severe PCM . Groups of weanling male rats were fed a diet containing 0.8% protein (PCM) or 24% protein (control) . A third group (pair fed) was fed limited amounts of the control diet that matched the mean daily dietary intake of the PCM group . After 4 wk on the diets, alveolar macrophages from all three groups functioned similarly with respect to surface adherence, phagocytosis and killing of Listeria monocytogenes, release of hydrogen peroxide and superoxide anion, and production of IL-1 and TNF . In contrast, Listeria-stimulated alveolar macrophages from the PCM group exhibited a marked shift in arachidonic acid metabolism, with impaired production of leukotriene B4 and enhanced release of thromboxane B2 and PGE2 . The membrane arachidonic acid content and the uptake of {3H}arachidonate by alveolar macrophages did not differ among the three groups . The shift toward the cyclooxygenase pathway was not seen after 2 wk of dietary restriction and was reversed if PCM animals were fed the control diet for 1 wk . Thus, PCM does not affect the antimicrobial activity or cytokine production of alveolar macrophages, but causes alterations in arachidonic acid metabolism that may interfere with the modulatory functions of alveolar macrophages.

FEMS Microbiol Lett, 1990 Jan 15, 55(1-2), 113 - 9
Revision of the antigenic structure of genus Listeria; Garcia JA et al.; O-antigenic structure of genus Listeria was studied, using antisera (obtained from rabbits) against different O-antigens of reference strains of each serovar . The titres of sera were determined by agglutination using antigens of the same reference strains as well . Some differences from the actual scheme were found: serum antifactor-IX gave a lower titre than expected against antigens 4ab and 6b, while the titre observed against antigen 4b was higher than the expected in this case . Serum antifactor-VIII presented a higher titre than could be expected against antigen 6b . The strains of serovars 4d and 4e used in this experience were impossible to distinguish, and could have been classified in the same serovar . We could not obtain serum antifactor-XI from serovar 6b after several trials . From these differences we propose some modifications of the current antigenic scheme of genus Listeria.

Scand J Infect Dis, 1990, 22(1), 101 - 3
Meningoencephalitis with septic intracerebral infarction: a new feature of CNS listeriosis; Nau R et al.; The broad spectrum of CNS listeriosis is expanded by the observation of an intracerebral infarction associated with meningoencephalitis . Sequential CCT scans in a 66-year-old immuno-compromised woman led to the clinical diagnosis of brain abscess . Autopsy revealed an infected intracerebral infarction most probably due to temporal occlusion of the middle cerebral artery by septic microemboli or septic endothelial damage.

Ann Rheum Dis, 1990 Jan, 49(1), 58 - 9
Listeria monocytogenes infection in a prosthetic knee joint in rheumatoid arthritis; Booth LV et al.; The prosthetic knee joint of a 64 year old woman with severe rheumatoid arthritis was found to be infected with Listeria monocytogenes . After treatment with intravenous antibiotics, symptoms gradually resolved . She subsequently received prolonged treatment with oral co-trimoxazole and 18 months later remained well.

Heart Lung, 1990 Jan, 19(1), 21 - 3
Listeria monocytogenes meningitis in a human immunodeficiency virus-positive patient undergoing hemodialysis; Calubiran OV et al.; Listeria monocytogenes bacteremia without meningitis has been reported in patients who have undergone long-term hemodialysis and have transfusional iron overload . On the other hand, cases of Listeria bacteremia without meningitis have occurred sporadically among the acquired immunodeficiency syndrome population, mostly homosexuals . There have been no reports of Listeria meningitis occurring among persons who are antibody positive to human immunodeficiency virus or are intravenous drug abusers having chronic renal failure and undergoing hemodialysis . This patient represents the first case of Listeria bacteremia and meningitis to occur in an intravenous drug abuser who is human immunodeficient antibody positive, is receiving hemodialysis, and has transfusional iron overload.

Bull Soc Sci Med Grand Duche Luxemb, 1990, 127(1), 41 - 3
Camembert, Listeria and the immunocompromised patient; Ries F et al.; Listeriosis is a rare but well known infectious complication in pregnant women and immunocompromised patients . Epidemiological studies have shown an association between listeriosis and alimentary contamination by listeria of a variety of foodstuff including soft, ripened cheeses . We describe two case-reports of listeria meningitis with high evidence of food-related illness due to the consumption of contaminated camembert . These observations urged our State Department of Health to formulate a communication about alimentary listeriosis at the intent of all health care professionals, including recommendations for patients at risk.

Acta Microbiol Hung, 1990, 37(2), 223 - 5
Listeria isolation from foods of animal origin; Nitcheva L et al.; Microbiological examination of Listeria, isolated from foods of animal origin was carried out during the period 1986-1987 . A total of 642 samples from chicken, beef and pork raw meats, fish, eggs and from the environment were investigated . Using the cold technique, Stuart's transport medium, tryptose broth and Ralovich's medium, 76 Listeria strains of serogroup 1 and 2 were isolated.

Acta Microbiol Hung, 1990, 37(1), 97 - 9
Monocytosis producing activity from virulent and avirulent strains of Listeria; Galsworthy SB; Monocytosis is a hallmark of listeriosis in many species . A similar phenomenon is induced by a monocytosis-producing activity (MPA) purified from the organism . The relationship between MPA production and virulence is unclear . The purpose of this study was to measure MPA in extracts prepared from strains with known degrees of virulence and haemolysin production . Differential leukocyte counts on peripheral blood cells were performed 24, 48 and 72 h after injection of 0.5 mg MPA . In the strains we tested those known to be virulent produced monocytosis; those which were avirulent did not.

Acta Microbiol Hung, 1990, 37(1), 123 - 9
Identification of species of the Genus listeria by fermentation of carbohydrates and enzymatic patterns; Mira-Gutierrez J et al.; Patterns of carbohydrates and determination of API ZYM and API oxidases can be considered a useful way to differentiate the strains of Listeria . With all this information it is possible to work out a schematic table that allows the identification of Listeria strains with a remarkable certainty . By numerical analysis four differentiated clusters have been demonstrated.

Acta Microbiol Hung, 1990, 37(1), 113 - 7
Effect of listeria infection on the allotransplantation reaction in cyclosporin A treated mice; Walencka M et al.; Allogeneic reaction of listeria-infected Balb/c mice to C3H skin graft was examined . The recipients were infected with Listeria innocua and treated with Cyclosporin A . Listeria infection in the treated mice enhanced skin rejection reaction reduced by the immunosuppressor.

J Rheumatol, 1990 Jan, 17(1), 111 - 3
Septic arthritis due to Listeria monocytogenes: report and review of the literature; Massarotti EM et al.; Septic arthritis due to Listeria monocytogenes is an uncommon infection amenable to antibiotic therapy along with open or closed drainage . We report successful antibiotic treatment of a prosthetic joint infection in a man with seropositive rheumatoid arthritis and present a review of the literature describing this specific infection.

J Rheumatol, 1990 Jan, 17(1), 107 - 10
Listeria monocytogenes osteomyelitis complicating leukemia: report and literature review of Listeria osteoarticular infections; Louthrenoo W et al.; A 43-year-old black man with chronic lymphocytic leukemia treated with chemotherapy developed painful swelling of the 4th finger determined to be due to Listeria monocytogenes osteomyelitis . He recovered with 6 weeks' treatment with oral trimethoprim-sulfamethoxazole . Osteoarticular infections due to Listeria monocytogenes are reviewed.

Int J Immunopharmacol, 1990, 12(4), 373 - 83
Augmentation of host defense against Listeria monocytogenes infection by oral administration with polysaccharide RBS (RON); Takeda Y et al.; Protection against Listeria monocytogenes in mice was enhanced by oral administration with a 30 mg/kg/day dose of polysaccharide RBS for 10 days . In mice treated with RBS, an enhanced elimination in vivo of L . monocytogenes was observed at the relatively late phase of listerial infection in correlation with enhanced immune responses against L . monocytogenes . The peritoneal macrophages from mice treated with RBS exhibited an increased activity of accessory cells for immune responses as assessed by production of interleukin-1 and antigen presentation to Listeria-immune T-cells . An increased activity of macrophages acting as accessory cells for immune responses may play important roles in the enhanced resistance against L . monocytogenes in mice treated orally with RBS.

Arch Microbiol, 1990, 153(3), 282 - 6
Adherence of a virulent strain of Listeria monocytogenes to the surface of a hepatocarcinoma cell line via lectin-substrate interaction; Cowart RE et al.; Listeria monocytogenes was examined for the presence of surface carbohydrates to ascertain whether surface sugars, if present, would interact with eucaryotic surface carbohydrate receptors . We found that a virulent, but not two avirulent strains had a surface alpha-D-galactose residue as determined by agglutination with Griffonia simplicifolia (GS-I) and other lectins . The virulent strain bound to a human hepatocarcinoma cell line (HepG2), which has a well characterized receptor for alpha-D-galactose . This interaction could be blocked by pretreatment of the HepG2 cells with either alpha-D-galactose or neuraminidase, the latter of which will render the galactose receptor functionally inactive . We propose that the attachment of the virulent Listeria to eucaryotic cells occurs as a result of the interaction of the microbial alpha-D-galactose with that of the eucaryotic galactose receptor . This surface carbohydrate may provide an explanation for the mechanism of attachment and penetration of virulent Listeria into host cells during infection . As such, this may allow for amplification of pathogenesis through intracellular multiplication in nonprofessional phagocytes prior to macrophage involvement.

G Batteriol Virol Immunol, 1990 Jan-Dec, 83(1-12), 125 - 31
{Listeriosis as an infection of food origin}; Caramello S et al.; After analysing the etiopathogenesis and transmission process of the microorganism, the Authors have examined the latest and documented outbreaks owing to food-borne strains of Listeria monocytogenes in Europe and in North America . The considered studies indicate an increase of listeriosis cases caused by infected food, especially food of animal origin, such as meat and milk-dairy products.

Pol Arch Weter, 1990, 30(3-4), 125 - 40
{Evaluation of immunostimulation of sheep with Propionibacterium acnes strain CN 5936 in the prevention of listeriosis}; Furowicz A et al.; The purpose of this work was to observe and estimate immune reaction taking place in pregnant sheep and their progeny after applying immunomodulator being a formalized culture strain Propionibacterium acnes CN 5936 {PA} . This biological preparation was used in order to reduce the endemic form of listeriosis in a big flock of sheep . 15 pregnant sheep were vaccinated with PA 4 weeks before the date of delivery and later, the sheep's progeny at the age of 3 weeks . During that experiment immunological, clinical and breeding estimations were carried out . The results of the experiment allow to draw a conclusion that the PA immunomodulator causes a considerable increase in specific cell-mediated parametres in pregnant sheep . The above described experiment of modulating pregnant sheep and their progeny reduces considerably lambs' clinical symptoms and mortality caused by listeriosis . Moreover, this method of immunoprophylaxis positively affects lambs' weight increase.

Cytokine, 1990 Jan, 2(1), 29 - 34
Treatment with anti-tumor necrosis factor alpha does not influence the immune pathological response against lymphocytic choriomeningitis virus; Leist TP et al.; The role of tumor necrosis factor alpha (TNF alpha) in the immunopathological events induced by infection with lymphocytic choriomeningitis (LCM) virus (LCMV) was assessed by treatment of C57Bl/6 mice with a sheep antibody to murine TNF alpha antiserum to strongly interfere with anti-Listeria host defense . However, despite its effectiveness in Listeria infections in vivo, antibody to TNF alpha used at 6 x 10(4) neutralizing units per day subcutaneously had no detectable influence on the kinetics of maturation of antiviral cytotoxic T-cell activity, inflammatory processes, or clearance of virus . First, onset and severity of LCMV-induced hepatitis, as assessed by cytotoxic T-cell activity, viral titers in the liver, serum liver enzyme values, and histology, were not detectably affected by antibody to TNF alpha . Second, incidence of lethal LCM disease after intracerebral infection and the kinetics of the primary footpad swelling reaction observed after local foot inoculation were not altered by anti-TNF alpha antibody treatment . From the data presented we conclude that TNF alpha as assayed by in vivo therapy with a polyclonal anti-TNF alpha antibody plays no detectable role in the host reaction against LCMV.

Nat Immun Cell Growth Regul, 1990, 9(6), 376 - 86
In vivo administration of anti-asialo-GM1 antibody enhances splenic clearance of Listeria monocytogenes; Schultheis RJ et al.; Resistance of mice to infection by Listeria monocytogenes involves a biphasic response . The first phase consists of the first 48 h after infection, during which there is multiplication of Listeria in the liver and spleen of infected mice . In these nonimmune mice, macrophages and polymorphonuclear leukocytes are the effector cells involved in controlling multiplication . In the second phase, cell-mediated immunity develops, beginning on day 2, during which multiplication of Listeria is prevented by macrophages possessing increased microbicidal activity that is mediated through the action of lymphokines released by immunologically committed T lymphocytes . The purpose of the present study was to define a role for natural killer (NK) cells in natural resistance to Listeria during the first 48 h after infection, prior to the development of specific immunity . Splenic NK cell activity was enhanced following a sublethal intravenous injection of viable Listeria as early as 24 h after injection and remained elevated throughout the nonimmune phase of infection . Interestingly, treatment of mice with anti-asialo-GM1 significantly enhanced the ability of mice to clear Listeria from the spleen relative to infected controls possessing intact NK cell populations . This was evidenced by 23-fold fewer bacteria obtained from the spleens of anti-asialo-GM1-treated mice . In addition, Percoll-enriched NK cell populations obtained from 48-hour Listeria-infected mice do not exhibit in vitro listericidal activity . These observations suggest a regulatory role of NK cells in resistance against Listeria and preclude a role for NK cells in direct cytolysis . Perhaps these cells modulate the immune response to Listeria by down-regulating the activity of the immune cells crucial to listerial resistance.

Acta Microbiol Hung, 1990, 37(2), 227 - 31
Penicillin binding proteins in Listeria monocytogenes; Vicente MF et al.; Membranes of Listeria were obtained from protoplasts and treated with 125I-ampicillin as probe, at different concentrations . Eight bands, corresponding to proteins labelled with the probe were detected their molecular weight ranged from 38,000 to 100,000, being the predominant ones at 95,000; 85,000; 60,000; 49,000 and 38,000 . The copy number of each PBP was also estimated . By means of competitive experiments the binding pattern of ampicillin, mecillinam, piperacillin, cefalotin, cefaloridine, cefoxitin, cefotaxime, azthreonam and imipenem was studied . The most effective binding was obtained with ampicillin, piperacillin and imipenem . Cefotaxime, and particularly cefoxitin, present an extremely low binding ability . The amount of antibiotic concentration preventing an effective label by the radioactive probe to the detected penicillin binding proteins seems to correlate with the lethal concentration of the different antibiotics on Listeria monocytogenes and explains the natural resistance of this genus to certain beta-lactamic compounds.

Microbiol Immunol, 1990, 34(7), 631 - 4
Isolation of Listeria monocytogenes from raw milk and its environment at dairy farms in Japan; Takai S et al.; The incidence of Listeria monocytogenes contamination in raw milk from farm bulk tanks and silage was investigated monthly at 20 dairy farms in Aomori prefecture, Japan, from January to July in 1989 . Listeria sp . was isolated from one sample (5%) of raw milk collected in May, but L . monocytogenes was not isolated from raw milk . L . monocytogenes was isolated from two samples of silage (10%) collected in June . Silage, cow feces, sawdust bedding, dust and soil in these farms were tested for listerias, and we confirmed listerias contamination of the environment in the dairy farms.

Acta Microbiol Hung, 1990, 37(1), 135 - 44
Haematological reactions of rabbits infected intravenously with Listeria strains of different virulence; Mazing YuA et al.; Listeria strains of different virulence were injected intravenously into rabbits of both sexes (2-4 kg) . The infectious dose was 10(8) cells/kg . Blood samples were taken from the ear wein one day and immediately before the infection, then 3 h, 1, 2, 3, 6 and 10 days after it . Total white blood cell counts and their changes were determined and the number of lysosomal granules in neutrophils were counted . A marked monocytic reaction was observed after the injection of virulent Listeria monocytogenes 18 and 87/5467, partly virulent Listeria ivanovii, non-pathogenic Listeria seeligeri 87/5626 and 87/5575, and Listeria murrayi G44 strains . A late slow growth was provoked by Listeria innocua C644 and a very slight reaction by Listeria welshimeri 1830 strains . There was no change after injection of L . innocua strain 10 . The number of lysosomal granules decreased significantly and remained at a low level for 6 days after the infection of L . monocytogenes strain 18 and for 3 days after the injection of L . innocua strain 10.

Acta Microbiol Hung, 1990, 37(1), 131 - 3
Comparison of allergenic skin test with serological and bacteriological examinations of cattle for Listeria monocytogenes; Kovincic I et al.; Five herds, each containing 200 to 300 cows, were surveyed for listeriosis . Since listeriosis is predominantly linked to reproductive diseases in the surveyed area, suspected cows were first selected according to the records on their previous reproductive disorders such as abortion, endometritis and sterility . By simultaneous serological, bacteriological and skin allergenic testing 40 cows suffering from listeriosis were detected . But, only seven of those cows were occasionally shedding listeriae in milk . The specific agglutinins for Listeria monocytogenes were detected in blood sera of all seven cows and the titre was from 1:20 to 1:160 . The difference of skin thickness induced by allergenic test was from 1 to 2 mm . L . monocytogenes was isolated from milk of all seven cows and indirectly through the inoculation in enrichment broth, and directly only from milk of two cows . The results indicate that the positive skin allergenic and serological tests do not necessarily mean the shedding of listeriae in milk . However, the listeria-shedding in milk was always accompanied by a positive skin allergenic test and the presence of agglutinins in blood sera.

Acta Microbiol Hung, 1990, 37(1), 119 - 22
Study of Listeria monocytogenes survival during the preparation and the conservation of two kinds of dairy product; Cottin J et al.; We tested yoghurts and soft cheeses for survival of Listeria monocytogenes during their manufacture and their storage at 4 degrees C . In yoghurt, even when the concentration of germs is high, the bacterial population decreased rapidly and the life of time of L . monocytogenes in this product depends on the sample acidity . The microorganisms disappear when the pH falls to 3.5 . In soft white cheeses, only a fabrication with chemical and bacterial ferments allows an acidity which is compatible with destruction of majority of L . monocytogenes . Under these conditions, the pH decreases to 4-4.5 according to the series of production.

Acta Microbiol Hung, 1990, 37(1), 105 - 11
Antibody response of dairy cattle experimentally infected with Listeria monocytogenes; Wesley IV et al.; The purpose of our study was to monitor the humoral immune response of 34 lactating dairy cattle experimentally infected with Listeria monocytogenes (strain Scott A, serotype 4b) . Twenty-seven animals were inoculated with 10(6) to 10(7) c.f.u./ml of L . monocytogenes via the intramammary route at ten day intervals for one month and 7 were inoculated with 4 x 10(2) to 4 x 10(3) c.f.u./ml . Preinfection and weekly-post infection serum and whey samples were prepared during acute infection . Antibody titres of serum and whey were evaluated in agglutination tests using whole-cell formalin-fixed L . monocytogenes suspensions . Preinfection agglutination titres ranged from 1:20 to 1:320 . At least four-dilution increase over pre-infection titres were apparent by the 8th week of infection . Eighty per cent of the bovine sera (26/34) exhibited titres of greater than or equal to 1:20, 480 . Whey titres, which reflected the local humoral response to L . monocytogenes, rarely exceeded 1:256 which may be ascribed in part to the lower immunoglobulin concentration in milk vs . blood . Antibody levels indicate active listeriosis but could not be used to predict the magnitude of the recovery of Listeria (c.f.u./ml) in milk.

Acta Microbiol Hung, 1990, 37(1), 101 - 4
Sensitivity of Listeria monocytogenes to irradiation; Tarjan V; Irradiation of Listeria monocytogenes was carried out in culture media and pork meat paste at room temperature with 60Co radiation source of 6.6 kGy.h-1 dose rate . The employed doses were 0, 0.5, 1, 2, 3, 4 and 6 kGy . Because of the expected great number of injured cells, parallel to the direct counting at selective media, liquid as well as solid resuscitation methods were used . One strain of out 3 survived as high as 4 kGy irradiation . Radiation with 2 kGy resulted 7 log cycles reduction of cell count . After lower irradiation doses the L . monocytogenes count decreased in proportion to increasing doses . It has been concluded that L . monocytogenes, compared with Gram-negative pathogens, are less sensitive to irradiation.

Int J Food Microbiol, 1990 Jan, 10(1), 43 - 50
Use of plasmid profiles and restriction endonuclease digest in environmental studies of Listeria spp . from raw milk; Fistrovici E et al.; Forty-eight isolates of Listeria spp . (19 L . monocytogenes, 27 L . innocua, 2 L . welshimeri) from bulk raw milk were screened for plasmid DNA . These isolates were collected over a period of 1 year . Only L . innocua harboured plasmids (8/27 strains) which ranged in size 10-44 megadaltons . The plasmid bearing strains could be arranged into three groups 10 Md, 44 Md and 44 + 10 Md . In two farms where Listeria innocua were persistent in bulk raw milk different plasmids profiles were found (farm 1 and 3) . In species carrying similar plasmid profiles (44 Md) isolated from the same bulk tank raw milk samples over a period of 2-4 months (farm 2) no similarities in restriction endonuclease digest patterns of the plasmids were observed . This study suggests there may be a constant influx of Listeria spp . into raw milk supplies on the farm.

Ophthalmologica, 1990, 201(1), 23 - 7
Listeria monocytogenes endophthalmitis in a renal-transplant patient receiving ciclosporin; Algan M et al.; Endophthalmitis due to Listeria monocytogenes developed suddenly in a 52-year-old man receiving immunosuppressive therapy for a renal transplantation carried out 2 months previously . The treatment combined low doses of ciclosporin and prednisone . The initial clinical picture was of acute hypertensive uveitis with hypopyon . Despite prompt paracentesis and appropriate antibiotic therapy, the long-term course was unfavorable, and enucleation became necessary . The occurrence of listeriosis is classic in renal-transplant recipients, but no ocular form has been reported hitherto.

Arch Androl, 1990, 25(1), 75 - 84
Biological functions of mouse seminal vesicle fluid . II . Role of water-soluble fraction of seminal vesicle fluid as a nonspecific immunomodulator; Emoto M et al.; The suppressive mechanisms of T cells induced by water-soluble fraction of mouse seminal vesicle fluid (WSF-SVF) were investigated to clarify its immunological roles in the reproductive immunity . WSF-SVF inhibited the blastogenic responses to concanavalin A (Con A) or phytohemagglutinin (PHA) of T cells . Pretreatment of splenocytes with WSF-SVF did not suppress the blastogenesis of splenocytes to Con A when treated cells were washed before cultures . WSF-SVF did not inhibit the proliferation of Con A-activated splenocytes, that of listeria-immune splenocytes to listeral antigen and growth of tumor cells (Yac 1 cells, Ehrlich ascites carcinoma cells, EL 4 cells) . Listerial antigen-specific immune response was not observed when mice were immunized with both listerial antigen and WSF-SVF, whereas it was observed when mice were immunized with only listerial antigen . WSF-SVF also significantly inhibited allogenic MLR . WSF-SVF did not adsorb Con A, and its suppressive activity was rather enhanced by heating at 56 degrees C for 30 min . These results suggest that WSF-SVF inhibits the stage of sensitization of T cells with antigen or stimulant, such as mitogen nonspecifically, without adsorption to antigen or mitogen, and its substance is stable.

Pharmacotherapy, 1990, 10(4), 301 - 4
Pharmacodynamics of trimethoprim-sulfamethoxazole in Listeria meningitis: a case report; Friedrich LV et al.; Infections in the cerebrospinal fluid (CSF) occur in an area of impaired host defenses; therefore, bactericidal antibiotics that reach adequate concentrations in the CSF are necessary for treatment . Measurements of antibiotic penetration into the CSF include CSF inhibitory and bactericidal titers, the absolute antibiotic concentration in the CSF, and the CSF: serum concentration ratio . We present the case of a patient with Listeria monocytogenes meningitis who failed to respond clinically to standard therapy, and whose organism demonstrated tolerance to Ampicillin (MBC: MIC = 258:1) that successfully responded to trimethoprim-sulfamethoxazole (TMP-SMX) . The CSF peak bactericidal titer to TMP-SMX was 1:8, corresponding to that reported as necessary for successful outcome in patients with meningitis . The CSF peak: MBC ratios for TMP and SMX were less than 3:1 and equal to 3:1, respectively . These individual ratios are lower than those suggested for successful treatment of meningitis; however, the recommended ratios were established using single agents and did not account for synergistic activity with a drug combination such as TMP-SMX . The failure of standard therapy in this patient underscores the importance of MIC/MBC testing when tolerance is suspected or when CSF penetration of antibiotics is relatively poor . In addition, measurements of CSF inhibitory and bactericidal titers, which incorporate the antibiotic concentration in the CSF, susceptibility of the infecting microorganism, and host defense factors, may be useful in monitoring patients with meningitis.

Lung, 1990, 168 Suppl, 1025 - 32
Cytokines in antibacterial resistance: possible applications for immunomodulation; Kaufmann SH et al.; Acquired resistance to intracellular bacteria is primarily mediated by T cells which--by secreting multiple interleukins (ILs)--activate antimicrobial activities in mononuclear phagocytes . Experimental infection of mice with Listeria monocytogenes and Mycobacterium bovis has helped to clarify the role of ILs in antimicrobial infection . These studies revealed: 1) application of IFN-gamma reduces the number of L . monocytogenes and treatment with anti-IFN-gamma antibodies worsens listeriosis; 2) in vitro, tuberculostatic and listericidal macrophage functions are activated by IFN-gamma, IL-4, and IL-6; 3) tumor necrosis factor (TNF) synergizes with IFN-gamma; 4) treatment with anti-TNF antibodies worsens listeriosis and interferes with M . bovis-induced granuloma formation; 5) concomitant application of mycobacterial products and TNF induces necrotic reactions . In humans at least some effects of IFN-gamma on macrophages may be mediated via 1,25-dihydroxyvitamin D3 . These findings illustrate the multifaceted role of ILs in antimicrobial resistance and point to a central role of IFN-gamma.

Med Microbiol Immunol (Berl), 1990, 179(2), 95 - 104
Role of tumor necrosis factor in Listeria resistance of nude mice; Hauser T et al.; The effects of sheep anti-murine recombinant tumor necrosis factor-alpha (TNF-alpha) on resistance to Listeria monocytogenes infection were studied in T cell-deficient nu/nu mice . The sheep anti-TNF-alpha antibody preparation was specific for TNF since it neutralized 300 U of recombinant murine TNF-alpha in vitro at a dilution of up to 1/1,000 but did not neutralize 32 U of interferon (IFN)-alpha, -beta or 32 U of IFN-gamma in vitro at a 1/20 dilution . When tested in vivo in sublethally Listeria-infected nu/nu or T cell-competent C57BL/6 or ICR mice, a single treatment of 0.2 ml anti-TNF-alpha given intraperitoneally on either day -1,0 or +1 resulted in the death of mice by day 5-7 due to the uncontrolled growth of Listeria; bacterial counts in spleen and liver were increased on days 3-5 by a factor of 10-1,000 in these organs . When examined histologically, organs from mice with the anti-TNF-alpha treatment contained more, and considerably bigger, lesions that exhibited central necrosis . The enhancing effect of anti-TNF-alpha on Listeria infection seemed greater early during Listeria infection on days 1-6 when compared to later phases of the infection around days 6-10 . From the data presented we conclude that in addition to other lymphokines, such as IFN-gamma, TNF-alpha is of importance during the entire course of a Listeria infection in nu/nu mice.

J Antimicrob Chemother, 1990 Jan, 25(1), 121 - 6
Treatment of experimental listeriosis by CI 934, a new quinolone; Hof H; CI 934, a new quinolone, is only marginally more active in vitro against Listeria monocytogenes and other Listeria spp . than ciprofloxacin . A bactericidal effect is seen only after several hours of incubation . However, mice infected with a virulent strain of L . monocytogenes were protected by parenteral treatment with CI 934 . With a dosage of 2 x 2 mg CI 934 per day for three days almost complete remission could be achieved . These results are somewhat better than those obtained in previous experiments with other antibiotics.

Appl Environ Microbiol, 1990 Jan, 56(1), 167 - 9
Selective plating medium for quantitative recovery of food-borne Listeria monocytogenes; Lachica RV; A new plating medium (lithium chloride-ceftazidime agar {LCA}) was designed to quantitatively recover food-borne Listeria monocytogenes in the form of large colonies while inhibiting most other food-borne microorganisms . This medium included brain heart infusion agar as the nutritive agar base and a combination of selective agents (LiCl, glycine anhydride, and ceftazidime) . Comparison of LCA and lithium chloride-phenylethanol-moxalactam agar (LPM) indicated that both were equally effective for the enumeration of the cold-tolerant pathogen in artificially and naturally contaminated foods . However, LCA was more effective than LPM in the recovery of sublethally heat-injured cells . Moreover, Listeria colonies on LCA exhibited a more distinct bluish hue than those on LPM when viewed by the Henry oblique transillumination technique.

Int J Immunopharmacol, 1990, 12(1), 11 - 8
Preclinical screening and analysis of the immunotoxic and immunomodulatory activity using a multiple immunoassay (MIA) in mice; Nouza K et al.; Screening and analysis of immunotoxic and immunomodulatory activity has become an integral component in preclinical studies of pharmaceuticals and xenobiotics . In an attempt to replace laborious and expensive batteries of assays used at present we developed a multiple immunoassay (MIA) enabling the determination, in a single mouse, of: the weight of the thymus, spleen and a group of lymph nodes; delayed type hypersensitivity and antibody response to SRBC; phagocytic activity of peritoneal macrophages and the responsiveness of spleen lymphocytes to "T" (PHA, ConA) and "B" (LPS) mitogens in vitro . The MIA responsiveness to two prototype immunostimulators (Thymostimulin and Listeria factor Ei) was tested at two time periods after antigenic stimulation, not only in normal mice, but also in animals with selectively depressed T-systems (anti-Thy1.2 monoclonal antibody) and B-systems (cyclophosphamide); in both dexamethasone-treated and irradiated animals . The findings indicate, that this MIA is capable of reflecting both immunosuppressive and immunostimulatory activities of the tested agents and permits partial insight into the mechanisms underlying these activities.

J Acquir Immune Defic Syndr, 1990, 3(2), 139 - 43
Listeriosis in patients with HIV infection: clinical manifestations and response to therapy; Kales CP et al.; Although listeriosis is an uncommon infection in patients with human immunodeficiency virus (HIV) infection, the frequency of listeriosis in New York City has increased because of the increase in the number of HIV-infected patients . The medical records of 30 patients admitted to three medical centers in New York City from 1981 to 1988 with infections due to Listeria monocytogenes were reviewed . Six patients had AIDS, one was seropositive and asymptomatic, and four had risk factors for HIV infection . While the annual number of cases of listeriosis in patients without risk factors for HIV infection was constant, 9 of the 11 patients with AIDS or with risk factors for HIV infection presented with listeriosis between 1985 and 1988, the last half of the survey period . These patients were male homosexuals or intravenous drug abusers, and all but one were black or Hispanic . Manifestations of listeriosis in patients with AIDS or with risk factors for HIV infection included bacteremia without apparent source in seven, meningitis in three, and endocarditis in one, syndromes that were similar to those in patients without risk factors for HIV infection . Ten of 11 patients were treated with penicillin or ampicillin, and 7 were also given an aminoglycoside . All patients responded well to therapy and no relapses were observed . Physicians should include antibiotics effective against L . monocytogenes when treating AIDS patients with meningitis of unknown origin and consider the diagnosis of listeriosis in patients with sepsis of unknown origin.

Cell Immunol, 1990 Jan, 125(1), 261 - 7
A homogeneous population of lymphokine-activated killer (LAK) cells is incapable of killing virus-, bacteria-, or parasite-infected macrophages; Zychlinsky A et al.; Previous reports have suggested a role for natural killer (NK) cells in directly lysing host cells infected with bacteria and other intracellular microorganisms . Here, we determined the inability of a highly homogeneous population of lymphokine activated killer (LAK) cells to kill macrophages infected with the following intracellular parasites: Mycobacterium avium, Listeria monocytogenes, Legionella pneumophila, Toxoplasma gondii, and Trypanosoma cruzi . In parallel cytotoxicity assays, LAK cells lysed the tumor targets YAC-1 and P815 effectively . Furthermore, we were able to demonstrate that influenza-specific cytotoxic T lymphocytes (CTL), but not LAK cells, were efficient killers of influenza virus-infected macrophages.

Immunopharmacol Immunotoxicol, 1990, 12(4), 647 - 67
Induction of colony-stimulating factor(s) after administration of a traditional Chinese medicine, xiao-chai-hu-tang (Japanese name: shosaiko-to); Yonekura K et al.; Colony stimulating factor (CSF)-rich serum was obtained from mice injected intraperitoneally (ip) with shosaiko-to, a traditional Chinese herbal medicine . Transfer of the CSF-rich serum into naive mice augmented the resistance against Listeria monocytogenes . A dose-dependent induction of CSF was observed in mice given shosaiko-to via intravenous route as well as via intraperitoneal route . Since the serum CSF induction was observed in both lipopolysaccharide (LPS)-responder C3H/He mice and LPS-non-responder C3H/HeJ mice, the effect of shosaiko-to seemed to be independent of possibly contaminating LPS . The level of serum CSF induced by shosaiko-to in athymic nude mice was similar to that in control euthymic mice, and the induction of CSF was completely blocked by the previous administration of carrageenan, a selective macrophage-blocker . In mice treated ip with shosaiko-to CSF activity was detected in the peritoneal cavity, the site of injection, and the time course was similar to that of serum CSF induction . In a bone marrow culture system, the composition of colonies formed by shosaiko-to-induced CSF was similar to that formed by standard GM-CSF . The CSF activity was scarcely affected by treatment of the sera with anti-M-CSF antibody . These results suggest that shosaiko-to augments the host defense by inducing mainly GM-CSF, and that CSF is produced by cells of macrophage lineage . In addition, it was shown that CSF could be induced even after oral administration of herbal medicines.

J Clin Dent, 1990 Fall, 2(2), 43 - 7
Surface free energies and elemental surface compositions of human enamel after application of commercially available mouthrinses and adsorption of salivary constituents; Perdok JF et al.; The adsorption of active agents from six commercially available mouthrinses to ground and polished enamel, with and without adsorbed salivary constituents, was monitored by contact angle measurements and X-ray Photoelectron Spectroscopy (XPS) . Human enamel samples were treated with mouthrinses containing chlorhexidine (Peridex), stannous fluoride/amine fluoride (Meridol), thymol/benzoic acid (Listerine), sanguinarine (Veadent), sodium fluoride (Prodent), or cetylpyridinium chloride (Merocet) . XPS indicated a sizeable adsorption of both active and non-active components for all products . After treatment, all enamel surface free energies increased except for the stannous fluoride/amine fluoride containing mouthrinse . It is suggested that non-active components in the products cause an increase in surface free energy . Despite this thermodynamically unfavorable increase in surface free energy, all rinses have plaque reducing effects, indicating that this unfavorable surface characteristic is overruled by the antibacterial properties of the components . Replacement of non-active components by less adsorbing surfactants could increase the efficiency of the products tested.

J Clin Dent, 1990 Fall, 2(2), 34 - 8
Clinical study of a C31G containing mouthrinse: effect on salivary microorganisms; Corner AM et al.; In vitro studies have demonstrated the antiplaque properties of C31G, a potent broad spectrum antimicrobial agent consisting of an equimolar mixture of alkyl dimethyl glycine and alkyl dimethyl amine oxide, buffered with citric acid . In this initial clinical study, C31G at concentrations of 0.05%, 0.1%, 0.2% and 0.5% . Listerine, and placebo were tested in a complete crossover design . Twelve subjects were evaluated, with a minimum of 2 days between treatments . Parameters monitored were salivary bacterial counts and saliva glycolysis . The 0.5% and 0.2% C31G mouthrinses significantly reduced total bacterial counts in saliva samples obtained up to and including three hours after rinsing, compared with counts obtained prerinsing or after placebo rinsing . Both 0.5%, and 0.2% C31G significantly inhibited glycolysis of salivary bacteria for up to 6 hours postrinsing, compared with pH values obtained prerinsing . 0.1% and 0.05% C31G exhibited little or no effect in either assay . Listerine showed a significant reduction in bacterial counts for up to 1 hour postrinsing, compared with prerinse counts, but the effect was less sustained . Listerine showed no significant inhibition of glycolysis at any time point . No tooth staining or altered taste sensation was noted with either product.

Acta Microbiol Hung, 1990, 37(1), 81 - 5
Chemotaxis in Listeria monocytogenes; Galsworthy SB et al.; Listeria monocytogenes is a flagellated bacterium with a characteristic tumbling motion . It is intriguing to speculate that directional motility might facilitate penetration of the intestinal epithelium or selective colonization of the central nervous system or gravid uterus . There are conflicting reports on the extent of flagellation and degree of motility at temperatures corresponding to the internal environment of the mammalian host . No studies of chemotaxis in Listeria have been reported . We examined Listeria for flagella, motility, and chemotaxis after growth at 10 degrees, 24 degrees, 30 degrees, 37 degrees and 40 degrees C . Listeria grown at all temperatures possessed flagella and were motile to at least some degree . Those grown at 24 degrees or 30 degrees C were the most abundantly flagellated and the most vigorously motile . The bacteria were able to swim towards tryptose at all temperatures and toward glucose at all temperatures except 40 degrees C.

Acta Microbiol Hung, 1990, 37(1), 93 - 6
O antigenic structure of Listeria grayi and Listeria murrayi; Vazquez-Boland JA et al.; Cross-agglutination and absorption studies indicated that two serological reference strains of Listeria grayi and Listeria murrayi differed in at least one O factor . The serological analysis revealed that the unshared O factors are not present in other Listeria serovars . These results are not in accordance with the antigenic structure previously reported for L . grayi and L . murrayi, then a new O antigen formulation is proposed for these species: L . grayi (III), XII, XIV and XVI; L . murrayi (III), XII, XIV and XVII.

Acta Microbiol Hung, 1990, 37(1), 87 - 91
Revision of the O antigenic scheme of Listeria; Garcia Cabrera JA et al.; Factor sera against Listeria O antigens (serologic reference strains) were produced . The results confirm the validity of the O antigenic scheme established for Listeria, but show slight discrepancies in strains of serovars 4b, 4ab and 6b.

Arch Histol Cytol, 1990, 53 Suppl, 189 - 97
Canine hepatic vein branches associated with subendothelial mast cells and an adventitial lymphatic plexus; Takahashi-Iwanaga H et al.; Branches of the hepatic veins in the dog are equipped with peculiar, periodically arranged sphincter muscles which are known to constrict in response to hematogenous shock agents, causing the severe hepatic congestion characteristic of this species . As was confirmed in this study, the sphincters are more strongly and effectively disposed in the peripheral portion of the veins, including the sublobular and central veins . Mast cells were numerous around the sublobular branches, being specifically gathered beneath the endothelium as recorded by Fujita (1964) . The present observation light-microscopically extended his findings, particularly with regard to the distribution of the mast cells along the entire course of the hepatic vein branches--from the proximal trunks through the sublobular veins to the central veins . In addition, mast cell condensation was especially pronounced in the peripheral branches, apparently in accordance with the development of the sphincters . Electron microscope observation confirmed the subendothelial location of the mast cells and revealed that, through an endothelial gap, the cells may extend a microprocess into the venous lumen, thus enabling the direct detection of hematogenous agents . A suspension of a bacterium, Listeria monocytogenes, was injected into the dog livers to induce hepatitis, and the resulting pathologically altered parts of the organ were examined light-microscopically . A heavy infiltration of inflammatory cells was found around the peripheral branches of the hepatic veins . The lymphatics accompanying the veins often contained lymphocytes and macrophages at two days after the injection . At five days, the lymphatics were extremely distended and twisted . The subendothelial mast cells were not encountered at the sites of severe cell infiltration.(ABSTRACT TRUNCATED AT 250 WORDS)

J Immunol, 1989 Dec 15, 143(12), 4238 - 43
Predominant utilization of V beta 8+ T cell receptor genes in the H-2Ld-restricted cytotoxic T cell response against the immediate-early protein pp89 of the murine cytomegalovirus; Rodewald HR et al.; Cytotoxic T cell responses to the murine Cytomegalovirus (MCMV) were elicited in BALB/c mice (H-2d) by infectious virus . Eight days after infection, MCMV-primed local lymph node T cells were either depleted for T cells expressing a V beta 8+ TCR or separated into V beta 8+ and V beta 8- subpopulations by a cell sorter using the mAb F23.1 . T cells were then expanded in vitro under limiting dilution conditions in the presence of IL-2 and in the absence of viral Ag to avoid selection by Ag in vitro . Frequencies of CTL precursors specific for the Immediate-Early-Ag 1 of MCMV and restricted to H-2Ld were determined . L cells of the endogenous haplotype H-2k cotransfected with the genes for MCMV-IE 1 and H-2Ld were used as target cells . Detection of a CTL response required previous priming of the animals by infection in vivo (less than 1/10(6) for nonimmunized animals) . In primed animals CTL precursors of this specificity and restriction were three to fivefold more frequent in the V beta 8+ population (1/9.900 to 1/22.300) than in the V beta 8- population (1/57.000 to 1/87.200) . Control experiments showed that frequencies were not influenced by the treatment with the anti-V beta 8-antibody and the fluorescein-labeled anti-Ig itself . V beta 8+ and V beta 8- T cells did not reveal any frequency differences when several other responses were determined (TNP-specific self-restricted CTL precursor; Th cells specific for keyhole limpet hemocyanin or Listeria monocytogenes).

Bull Soc Ophtalmol Fr, 1989 Dec, 89(12), 1463 - 6
{Listeria endophthalmitis: an uncommon etiology}; Brasseur G et al.; Listeria monocytogenes is an uncommon cause infections: to our knowledge this is the seventh case of human endophthalmitis isoleted . An early diagnosis and therapy allowed an excellent functional recovery when compared to the reported cases of the literature.

Zentralbl Bakteriol, 1989 Dec, 272(2), 242 - 7
Isolation of Listeria from French meat products; Nicolas JA et al.; One hundred and ten Listeria strains were recovered from 378 meat samples: L . monocytogenes (68 strains), L . innocua (45) and L . welshimeri (7) . L . monocytogenes isolates mainly belonged to serogroup 1/2 (1/2: 23 strains; 1/2b: 1; 1/2c: 43; 4b: 1) . These results contrast those observed for 355 human strains isolated during the same period in France where serovar 4b strains were largely predominant (66.5%) . 45% of the strains were phage typable . These results underline the widespread occurrence of Listeria in meat products.

Zentralbl Hyg Umweltmed, 1989 Dec, 189(3), 272 - 6
Heat tolerance of free living and of intracellular Listeria; Ly TM et al.; Listeria monocytogenes, L . innocua, and L . seeligeri are ingested by Tetrahymena pyriformis . They are not killed but survive and lyse bacteriovorous protozoans after about 8 days . The question important in food processing whether intracellular L . monocytogenes are protected against pasteurization was investigated using a model of Tetrahymena containing previously ingested Listeria . The study showed that Tetrahymena containing Listeria are more susceptible against application of heat, but intracellular Listeria, phagocytized within Tetrahymena, are not more protected than free and extracellular bacteria . Therefore, a properly performed pasteurization, i.e . of milk, kills intracellular Listeria as fast as extracellular living organisms . Finally, the pathogenic L . monocytogenes showed a higher susceptibility and lower tolerance against application of heat than apathogenic L . innocua and L . seeligeri.

Am J Vet Res, 1989 Dec, 50(12), 2009 - 13
Effects of dexamethasone on shedding of Listeria monocytogenes in dairy cattle; Wesley IV et al.; Ten lactating Holstein cows that had been given multiple injections of Listeria monocytogenes (serotype 4B, Scott A strain) via the intramammary route were allotted to 2 groups: group 1 (n = 5) was treated with the synthetic glucocorticoid, dexamethasone (0.04 mg/kg of body weight), for 3 consecutive days, and group 2 (n = 5) served as controls . Two days after the initial dexamethasone injection, the number of L monocytogenes in the milk had increased nearly 15-fold (1.16 log10) over pretreatment values . On day 3, Listeria numbers in the milk had increased by 1.83 log10, compared with pretreatment values . By day 4, Listeria numbers in the milk were approximately 100-fold (2.03 log10) greater than pretreatment numbers . Numbers remained high through day 7 and, by day 11, approached pretreatment numbers . Dexamethasone administration was accompanied by high total WBC and milk somatic cell counts and decreased eosinophil and lymphocyte numbers, and decreased milk production . The increase in shedding of L monocytogenes in the milk may reflect impairment of cell-mediated immune mechanisms and phagocytic cell functions that are critical for sustaining listerial immunity.

J Exp Med, 1989 Dec 1, 170(6), 2141 - 6
Gamma interferon limits access of Listeria monocytogenes to the macrophage cytoplasm; Portnoy DA et al.; The effect of rIFN-gamma and rTNF on the fate of hemolytic and nonhemolytic (hly-) Listeria monocytogenes in cultured mouse peritoneal macrophages was investigated . In untreated macrophages, approximately 80% of the hemolytic bacteria were killed during the first 2 h of incubation, but the survivors doubled between two and three times . In rIFN-gamma-treated macrophages, although the bacterial killing was identical to the controls during the first 2 h, there was no subsequent bacterial growth, and bactericidal activity continued for the duration of the experiment . rTNF has no affect by itself, but acted synergistically with rIFN-gamma to promote bacterial killing . Infected macrophages with or without rIFN-gamma were examined by EM . The results clearly showed that the role of rIFN-gamma was to prevent access of L . monocytogenes to the macrophage cytoplasm, which would prevent cell-to-cell spread of the bacteria . In addition, rIFN-gamma-treated macrophages exhibited enhanced digestive capacity of the intracellular bacteria.

Infect Immun, 1989 Dec, 57(12), 3695 - 701
Transcriptional mapping and nucleotide sequence of the Listeria monocytogenes hlyA region reveal structural features that may be involved in regulation; Mengaud J et al.; DNA sequence analysis of the regions adjacent to the hlyA gene, which encodes listeriolysin O, an essential virulence factor of Listeria monocytogenes, revealed the presence of two open reading frames (ORFs): ORF D located 304 base pairs downstream from hlyA, and ORF U located 224 base pairs upstream from and in opposite direction to hlyA . Promoter mapping performed with RNAs extracted from cells growing exponentially in rich medium showed that the three ORFs are independently transcribed . hlyA is transcribed from two promoters separated by 10 base pairs (P1 hlyA and P2 hlyA) . ORF U is transcribed in the opposite direction from an adjacent promoter . These two promoter regions are separated by a palindromic sequence T-T-A-A-C-A-A/T-T-G-T-T-A-A . This palindrome was also found upstream from the ORF D promoter, suggesting that all three genes are similarly regulated.

J Immunol, 1989 Dec 1, 143(11), 3731 - 6
MHC-unrestricted transfer of antilisterial immunity by freshly isolated immune CD8 spleen cells; Lukacs K et al.; Immune CD8 cells, which play an essential role in the adoptive transfer of antilisterial immunity, can specifically lyse Listeria-bearing macrophages in vitro in an MHC-unrestricted manner . In contrast, the adoptive transfer of immunity by unseparated immune lymphocytes has been reported to be MHC-restricted . To address the restriction properties of CD8 effectors in vivo, we assessed their efficacy in protecting syngeneic and allogeneic recipients . Protection was determined by comparing the number of viable splenic Listeria in naive mice and in recipients of 60 million CD8-enriched, L3T4-depleted, Listeria-immune spleen cells, 2 days after the infusion of 10,000 Listeria . Donor cells from B6 (H-2b) mice transferred about 4 logs of protection in syngeneic recipients and more than 2 logs in allogeneic B10.A (H-2a) or B10.BR (H-2k) mice . Immune B10.A CD8 cells transferred equivalent protection to B6 mice . Protection was almost completely abrogated by the lysis or lethal irradiation of CD8 cells before transfer in vivo . On the other hand, the depletion of macrophages or NK cells did not impair adoptive transfer . By comparison, nonimmune CD8 cells from normal mice or from mice stimulated with an irrelevant Ag in vivo did not transfer substantial immunity to allogeneic recipients . We have noted previously that protective CD8 cells inhibit phagocyte accumulation in the spleen of Listeria-infected syngeneic recipients . In the present studies, we observed similar changes in adoptively immunized allogeneic mice . Reduced phagocyte accumulation may reflect Listeria-dependent lysis of infected phagocytes by immune CD8 cells . In support of this, we showed that Listeria-immune donor cells rapidly acquired the capacity to mediate Listeria-dependent, MHC-unrestricted lysis of macrophages after incubation with small amounts of IL-2 in vitro . In sum, our data establish that Listeria-immune CD8 cells can function in vivo in MHC incompatible hosts, and indirectly support the hypothesis that the destruction of infected phagocytes may be important in T cell-mediated immunity against Listeria and perhaps other intracellular pathogens.

J Immunol, 1989 Nov 15, 143(10), 3330 - 7
Temporal development of protective cell-mediated and humoral immunity in BALB/c mice infected with Brucella abortus; Araya LN et al.; In BALB/c mice infected i.v . with attenuated strain 19 of Brucella abortus, the organism replicates to high numbers in the spleen and reaches peak concentrations at 2 wk postinfection (p.i.) . The infection is then progressively cleared so that by 8 wk p.i . numbers of bacteria have decreased 10,000 fold or more . Passive transfer assays were performed with T cell-enriched spleen cells and serum of donor mice infected 2, 3, 4, 5, 6, or 8 wk previously . Antibodies conferred significant protection to recipients at and after 3 wk p.i., whereas protection by T cells was not evident until 4 wk p.i . The combined transfer of serum and cells enhanced protection over that provided by serum or cells alone when transfers were made before, but not after, challenge infection . Protection conferred by T cell-enriched spleen cells of 6-wk donors was unaffected by the presence of equal quantities of cells from 3-wk donors, but was abrogated by the removal of both CD4 and CD8 T cell subsets . Experiments with purified CD4 and CD8 subsets revealed that cell-mediated protection resided at equivalent levels in both subsets . Daily treatment of mice with Cyclosporin A for 4 wk after infection caused some increase in numbers of brucellae in spleens and livers . Although immune responses of treated animals were markedly suppressed, there was little effect of treatment on numbers of macrophages in the spleen, on enhanced killing of Listeria monocytogenes in the spleen, or on the nature and intensity of splenic and hepatic inflammatory responses . These data indicate that acquired resistance to infection with B . abortus in mice is the result of independent, and probably also interactive, effects of antibodies and T effector cells of both CD4 and CD8 phenotypes . The initial decline in bacterial numbers in the spleen, which occurred in the absence of detectable cell-mediated immunity in that organ, could probably be ascribed principally to effects of antibodies and to nonimmune stimuli responsible for increased formation, attraction, and activation of macrophages.

Cancer, 1989 Nov 1, 64(9), 1968 - 70
Spectrum and outcome of microbiologically documented listeria monocytogenes infections in cancer patients; Khardori N et al.; At the M.D . Anderson Cancer Center (Houston), Listeria monocytogenes was cultured from 14 patients between 1980 and 1987 . The case records of 11 of these patients were reviewed . Underlying malignancies included acute leukemia (three), lymphoma (two), myeloma (one), adenocarcinoma of colon (two), carcinoma of breast (one), carcinoma of lung (one), and Kaposi's sarcoma associated with the acquired immune deficiency syndrome (one) . Listeria monocytogenes was cultured from blood (eight patients), cerebrospinal fluid (CSF) (two patients), and from both blood and CSF in one patient . All patients were receiving immunosuppressive therapy including corticosteroids in seven . An absolute neutrophil count of less than 1000/mm3 was noted in five . Bacteremia was the predominant type of infection and ten patients responded to antimicrobial therapy.

Br J Hosp Med, 1989 Nov, 42(5), 366 - 70
Listeriosis; Brightman CA et al.; Human listeriosis is still a rare disease in Great Britain, although the incidence appears to have increased in recent years . In this article the bacteriology, epidemiology, clinical features and treatment of this uncommon condition are discussed.

J Infect, 1989 Nov, 19(3), 263 - 6
Recurrent Listeria monocytogenes meningitis in a heart transplant recipient; Larner AJ et al.; A case of recurrent Listeria monocytogenes meningitis is reported, the two episodes arising 4 months and 8 months after the patient had received a heart transplant . Both episodes immediately followed increased doses of corticosteroids for allograft rejection . The source of infection was not identified . Previous reports and possible explanations of recurrent L . monocytogenes infection are reviewed.

Transplantation, 1989 Nov, 48(5), 848 - 55
Pregnancy as a natural model of allograft tolerance . Interactions between adherent macrophages and trophoblast populations; Lu CY et al.; From an immunologic viewpoint, the fetus with its paternal antigens may be considered a successful allograft in the maternal host . Understanding the basis of this host-allograft relationship remains a fundamental unsolved problem in transplantation immunobiology . We have previously demonstrated that local immunoregulation in the murine placenta prevented macrophage activities necessary for an effective response against the intracellular bacterium Listeria monocytogenes . Given the central role of macrophages both as antigen-presenting and cytolytic effector cells, such local immuno-regulation may ordinarily help prevent rejection of the fetoplacental unit with its paternal alloantigens by the maternal immune system . We therefore examined two types of interaction between macrophages and the placental cells that populate the maternal-fetal interface . (1) Upon activation to kill listeria efficiently, macrophages also acquire cytolytic capacities against some tumor and embryonic cells . We tested the hypothesis that macrophage activation in the placenta was inhibited to prevent macrophages from lysing fetal trophoblasts . We found, however, that trophoblasts isolated by dispase dispersion, differential isopyknic centrifugation, and adherence were not lysed by three different populations of cytolytic macrophages: (a) those activated in vivo during listeriosis, (b) peptone-elicited macrophages activated in vitro by recombinant interferon gamma and other lymphokines, and (c) the macrophage cell line RAW 264.7 activated in vitro . (2) Previous studies had demonstrated that cells from the placental region and their conditioned media inhibited a variety of lymphocyte functions . However, we found that these did not inhibit activation of adherent macrophages as assessed by induction of cell-surface Ia and acquisition of tumoricidal activity . In addition, under conditions where placental cells inhibited the proliferative response of a cloned CD4+ anti-Listeria T cell line to fixed, antigen-pulsed macrophages, the secretion of macrophage-activating lymphokines was not affected . These studies are important because they indicate that previously described suppressor systems in the murine placental region do not account for the profound local deficits in macrophage function seen during listeriosis.

FEMS Microbiol Lett, 1989 Nov, 53(1-2), 23 - 9
Mutations affecting hemolysin production in Listeria monocytogenes located outside the listeriolysin gene; Leimeister-Wachter M et al.; We have investigated the molecular basis of spontaneous mutations leading to non-hemolytic and avirulent variants of the Listeria monocytogenes serotype 1/2a strain NCTC 7973 using Southern hybridization to DNA fragments that harbor the listeriolysin gene (hlyA) and adjacent regions cloned from a L . monocytogenes serotype 1/2a strain . The analysis of such non-hemolytic variants revealed the presence of a deletion of 300 base pairs, located 1.6 kb upstream of an otherwise intact listeriolysin gene . The importance of regions upstream of the hlyA gene in controlling the expression of the listeriolysin gene was further emphasized by the detection of a transposon-derived nonhemolytic mutant in which the transposon had inserted approximately 200 bp upstream of the listeriolysin gene . We conclude that at least two elements, contained within a region encompassing 1.6 kb of sequences upstream of the hlyA gene, may be required for expression of the listeriolysin gene.

Int J Food Microbiol, 1989 Nov, 9(3), 249 - 68
Evaluation of enrichment procedures for recovering Listeria monocytogenes from dairy products; Lammerding AM et al.; Six different enrichment media and five selective plating media were compared for their suitability for the recovery of Listeria monocytogenes from dairy products . These included media used to test milk products by the U.S . Food and Drug Administration (FDA) and the U.S . Centers for Disease Control (CDC), and media developed by the U.S . Department of Agriculture (USDA) for testing meat and poultry products . Test samples included naturally contaminated goat's milk, cultured milk products and ice cream manufactured with L . monocytogenes, and unpasteurized milk inoculated with heat- and freeze-injured cells of L . monocytogenes . Generally, the media and two-stage enrichment protocol developed by the USDA, with plating of samples after two consecutive 24-h incubation periods, yielded better recoveries than all other enrichment media incubated for 24 h . A modified USDA procedure, incorporating nonselective pre-enrichment of samples by omitting acriflavine and nalidixic acid from the primary USDA enrichment broth, and transfer of a larger volume of the initial culture broth to the secondary enrichment media, significantly increased recoveries of low numbers of sublethally stressed L . monocytogenes . Prolonged incubation of samples in the FDA enrichment broth, for 7 days, did not consistently improve recoveries over the initial 24-h incubation time of the medium . The selective plating medium developed by the USDA, lithium chloride-phenylethanol-moxalactam agar, was the most effective plating agar for isolation of L . monocytogenes following enrichment of samples in any broth culture, and increased recoveries of L . monocytogenes by 19-40% compared with other selective agar media tested.

Int J Food Microbiol, 1989 Nov, 9(3), 197 - 203
Persistence at source of Listeria spp . in raw milk; Slade PJ et al.; From 36 of 315 bulk tank sources of raw milk found to harbour Listeria spp., 34 were available for resampling at intervals to determine persistence of the organisms . Listeriae were reisolated from 21 sources . In 16 Listeria spp . were isolated in one retest . From the other five listeriae were obtained in more than one retest . Listerial populations were not particularly persistent . In all but one instance listeriae were not reisolated more than 5 months after initial sampling . Intermittent variations in Listeria spp . isolated were observed . Some repeat samples yielded the same species as originally identified, but sometimes only one of originally two species was isolated . On occasions completely different or additional species were found . The aetiology of listeriosis in cattle and contamination of raw milk is discussed.

Res Microbiol, 1989 Nov-Dec, 140(9), 631 - 43
Sequences homologous to the listeriolysin O gene region of Listeria monocytogenes are present in virulent and avirulent haemolytic species of the genus Listeria; Gormley E et al.; Various parts of the hlyA gene region of Listeria monocytogenes which encodes a major virulence factor, listeriolysin O, have been used to detect the presence of homologous sequences in other species of the genus Listeria . Under low-stringency hybridization conditions, sequences homologous to the hlyA gene and its 5' adjacent regions were detected in the haemolytic and pathogenic species L . ivanovii, and in the haemolytic but non-pathogenic species L . seeligeri . In contrast, the region located downstream from hlyA appeared specific to L . monocytogenes . None of the probes spanning the region revealed homologies between L . monocytogenes and the non-pathogenic and non-haemolytic members of the genus, L . innocua, L . murrayi and L . welshimeri . Among various strains of L . monocytogenes tested, the gene hlyA and its 3' adjacent region appeared well-conserved . In contrast, a restriction length polymorphism was detected in the region located upstream from hlyA with no obvious correlation with the haemolytic phenotype or the serovar of the strains tested.

Appl Environ Microbiol, 1989 Nov, 55(11), 2802 - 5
Inhibition of Listeria monocytogenes growth by the lactoperoxidase-thiocyanate-H2O2 antimicrobial system; Siragusa GR et al.; The lactoperoxidase-thiocyanate-H2O2 system (LP system), consisting of lactoperoxidase (0.37 U/ml), KSCN (0.3 mM), and H2O2 (0.3 mM), delayed but did not prevent growth of L . monocytogenes Scott A at 5, 10, 20, and 30 degrees C in broth and at 20 degrees C in milk . The net lag periods determined spectrophotometrically varied inversely with temperature and were shorter at 5 and 10 degrees C for cultures from shaken versus from statically grown inocula . Lag periods for cultures from shaken and statically grown inocula, respectively, were 73 and 98 h at 5 degrees C, 22 and 32 h at 10 degrees C, both 8.9 h at 20 degrees C, and both 2.8 h at 30 degrees C . After the lag periods, the maximum specific growth rates were similar for each of the three treatments (complete LP system, H2O2 alone, or control broth) at 5, 10, and 20 degrees C and were 0.06 to 0.08, 0.09 to 0.1, and 0.32 to 0.36/h, respectively . At 20 degrees C in sterile reconstituted skim milk, the LP system restricted growth of Scott A, with log CFU counts per ml at 0, 36, and 68 h being 5.7, 6.4 and 7.9 (versus 5.7, 9.8, and 11.2 for controls) . Possible explanations for the decreased lag times observed for cultures from aerobically grown inocula are discussed.

FEMS Microbiol Lett, 1989 Nov, 53(1-2), 95 - 9
Preliminary evidence that different domains are involved in cytolytic activity and receptor (cholesterol) binding in listeriolysin O, the Listeria monocytogenes thiol-activated toxin; Vazquez-Boland JA et al.; The inactive truncated 52 Kilodaltons (kDa) Listeriolysin O (LLO) produced by a transposon Tn1545-induced Listeria monocytogenes non-hemolytic/avirulent mutant previously described (Gaillard et al . (1986) Infect . Immun . 52, 50-55), that lacks a 48 aminoacid fragment at the C-terminal end including the single cysteine residue essential for activity (Mengaud et al . (1988) Infect . Immun . 56, 766-772), bound to the SH-cytolysin membrane receptor cholesterol, as did the active 60 kDa toxin . These results indicate that the missing fragment is a functionally important region needed in the 60 kDa LLO to cause membrane-disruption but not to bind to cholesterol, which strongly suggests that in LLO (and presumably in the other SH-cytolysins, in accordance with their structural and functional homologies) different domains are involved in cytolytic activity and cholesterol binding . The cysteine residue contained in the missing fragment, therefore, would not be essential for cholesterol binding, as is currently thought, rather it seems to be essential specifically for cell lysis.

J Leukoc Biol, 1989 Nov, 46(5), 434 - 40
Gamma interferon induces monocyte killing of Listeria monocytogenes by an oxygen-dependent pathway; alpha- or beta-interferons by oxygen-independent pathways; Peck R; Human peripheral blood monocytes purified by counterflow centrifugal elutriation were treated with recombinant interferons-gamma (IFN-gamma), alpha (IFN-alpha), or beta (IFN-beta)--and tested for their capacity to kill Listeria monocytogenes . All three IFNs increased the monocyte bactericidal activity in a dose-dependent fashion . Exogeneous catalase, an inhibitor of monocyte-generated hydrogen peroxide, did not affect bactericidal activity . However, exogenous superoxide dismutase inhibited killing by IFN-gamma-activated monocytes, but not by IFN-alpha- or IFN-beta-activated monocytes . By contrast, exogenous soybean trypsin inhibitor inhibited killing by IFN-alpha or IFN-beta-activated monocytes, but not by IFN-gamma-activated monocytes . Combinations of IFN-gamma and IFN-alpha resulted in no increase in bactericidal activity . Finally, treatment with IFN-gamma resulted in different receptiveness of the cell to subsequent oxidative burst-stimulating signals than did treatment with either IFN-alpha or IFN-beta . These results suggest that monocytes treated with IFN-gamma kill L . monocytogenes by an oxygen-dependent mechanism, but treatment with IFN-alpha or IFN-beta elicits principally oxygen-independent mechanisms.

J Immunol, 1989 Nov 1, 143(9), 2894 - 9
Evidence that tumor necrosis factor has an important role in antibacterial resistance; Havell EA; TNF is produced in the spleens of Listeria-infected mice during the first 3 days of a sublethal immunizing infection . The production of Listeria-induced TNF coincides with the time when peak numbers of bacteria are present in the liver and spleen . Evidence suggesting that TNF produced in Listeria-infected organs functions in a T cell-independent resistance mechanism comes from results showing that listeriosis is exacerbated in both T cell-intact mice and T cell-deficient (athymic nude) mice treated with a monospecific anti-murine TNF IgG . Listeriosis is exacerbated, however, only if the anti-TNF IgG is given during the first 3 days of infection, i.e., at the time when TNF is being produced in the spleen . Anti-TNF IgG administered on the first day of infection neutralized all the cytotoxic activity of endogenously produced TNF in the spleen . Additional evidence that TNF plays an important role in antibacterial defenses was obtained by showing that administration of pure murine rTNF protects mice against a normally lethal Listeria challenge given 1 to 24 h later.

Infect Immun, 1989 Nov, 57(11), 3629 - 36
Listeriolysin O is essential for virulence of Listeria monocytogenes: direct evidence obtained by gene complementation; Cossart P et al.; The role of listeriolysin O in the intracellular multiplication of Listeria monocytogenes and, therefore, its pathogenicity was questioned through a genetic complementation study . A nonhemolytic mutant was generated by inserting a single copy of transposon Tn917 in the bacterial chromosome . This insertion was localized by DNA sequence analysis in hlyA, the gene coding for listeriolysin O . As was another mutant that we previously characterized, this mutant was avirulent in the mouse . It was transformed with a plasmid carrying only hlyA, able to replicate in L . monocytogenes, and stably maintained in vitro and in vivo . The complemented strain displayed a hemolytic phenotype identical to that of the wild-type strain and was fully virulent, therefore attributing a crucial role to listeriolysin O in virulence and excluding the hypothesis of a polar effect of the transposon insertion on genes adjacent to hlyA and possibly involved in virulence.

Infect Immun, 1989 Nov, 57(11), 3331 - 7
Interactions between endogenous gamma interferon and tumor necrosis factor in host resistance against primary and secondary Listeria monocytogenes infections; Nakane A et al.; Intravenous injection of rat anti-mouse gamma interferon (IFN-gamma) monoclonal antibody as well as rabbit anti-mouse tumor necrosis factor (TNF) antibody into mice which had received a sublethal infection with Listeria monocytogenes cells resulted in acceleration of listeriosis . Endogenous IFN-gamma seemed to be produced early in infection, because suppression of antilisterial resistance was significant when a single injection of anti-IFN-gamma monoclonal antibody was given on day 0 or day 1 of infection . Production of TNF but not of IFN-gamma in the bloodstream early in infection was inhibited by administration of anti-IFN-gamma monoclonal antibody . The suppressive effect of anti-IFN-gamma and anti-TNF antibodies on antilisterial resistance was not augmented by simultaneous administration of these antibodies . On the other hand, in the secondary infection, simultaneous administration of anti-IFN-gamma and anti-TNF antibodies, but not of either of these antibodies alone, into L . monocytogenes-immune mice resulted in high mortality and explosive multiplication of bacterial cells in the spleens and livers . These results suggest that endogenously produced IFN-gamma and TNF are both essential to the host defense against L . monocytogenes infection and that these cytokines might act by different modes between the primary infection and the secondary infection.

J Neurosurg, 1989 Oct, 71(4), 620 - 2
Symptomatic hydrocephalus and reversible spinal cord compression in Listeria monocytogenes meningitis . Case report; Raps EC et al.; Central nervous system infections with Listeria monocytogenes result in varied clinical syndromes ranging from meningitis to rhomboencephalitis . A case of Listeria meningitis complicated by symptomatic communicating hydrocephalus and hydrostatic cervical cord compression is presented which clinically and radiographically improved with aggressive ventricular drainage.

Infect Immun, 1989 Oct, 57(10), 3014 - 21
Treatment of mice with human recombinant interleukin-2 augments resistance to the facultative intracellular pathogen Listeria monocytogenes; Haak-Frendscho M et al.; The effects of exogenously administered human recombinant IL-2 (hrIL-2) on resistance to Listeria monocytogenes infection were examined . Intravenous injection of hrIL-2 significantly enhanced antibacterial resistance in both BDF1 and C3H/HeJ mice . The beneficial effect of hrIL-2 was observed with as little as 0.6 micrograms per mouse, whereas optimum protection occurred at 6 micrograms per mouse, hrIL-2 was equally protective when administered concomitant with the listeriae or up to 24 h prior to infection; it had little effect if given after the bacterial challenge . Kinetic experiments indicated that both the peak bacterial burden and the time lag before L . monocytogenes began to be cleared from the spleen and liver were reduced in hrIL-2-treated mice as compared with control mice . Histopathological examination of spleens and livers confirmed that hrIL-2-treated Listeria-infected mice experienced considerably less damage to these organs than did control mice . Spleen cells from Listeria-infected mice exhibited depressed levels of mitogen-induced proliferation coincident with the peak bacterial burden in the spleen and liver and during the subsequent recovery from the infection . Administration of hrIL-2 to uninfected mice had no effect on spleen cell proliferation in response to mitogens in vitro, nor did hrIL-2 treatment restore normal levels of splenocyte proliferative responses to Listeria-infected mice . In addition, hrIL-2 treatment resulted in attenuated levels of serum colony-stimulating activity in infected mice as compared with control infected mice . Coadministration of both hrIL-2 and human recombinant interleukin-1 alpha at various dose and time combinations had no detectable additive or synergistic effect . Although these data do not suggest an obvious mechanism of action, they clearly demonstrate that hrIL-2 can augment host defense against the facultative intracellular pathogen L . monocytogenes.

Cell Immunol, 1989 Oct 1, 123(1), 9 - 22
Comparison of the effects of IL-1 alpha and TNF-alpha on phagocyte accumulation and murine antibacterial immunity; Kurlander RJ et al.; IL-1 and TNF both are reported to increase host antibacterial resistance . To directly compare their effects on tissue phagocyte accumulation and antibacterial activity, we infused recombinant human IL-1 alpha and TNF-alpha into C3H/HeJ mice . Although IL-1, at a dose of 1 microgram/day, did not significantly elevate blood neutrophil concentrations, it increased the number of PMNs within the spleen three to fourfold within 2 days . Similar neutrophil accumulation also occurred in the lungs, bone marrow, and liver of treated animals without detectable changes in macrophage numbers . IL-1 also increased myelopoiesis in the spleen by Days 3-4 of infusions . The capacity of splenocytes from IL-1-treated animals to kill Listeria monocytogenes in vitro and to suppress listeria proliferation in vivo after the intravenous infusion of bacteria both rose in parallel with PMN accumulation . Comparable doses of TNF also enhanced listeria killing in vivo but in contrast to IL-1, it significantly depressed peripheral blood neutrophil counts, and inhibited splenic neutrophil accumulation and in vitro listericidal activity in listeria-infected mice . Our results suggest that IL-1 enhances host resistance to infection by increasing tissue neutrophil accumulation while TNF protects by a different mechanism, despite a net inhibitory effect on neutrophil accumulation.

J Immunol, 1989 Oct 1, 143(7), 2336 - 41
Secretion of colony-stimulating factors by T cell clones . Role in adoptive protection against Listeria monocytogenes; Magee DM et al.; CSF have been postulated to be important mediators of host defenses . The current studies were undertaken to investigate the production of CSF by Listeria-specific, T cell clones and to assess the participation of CSF in anti-listerial host resistance . Listeria-specific L3T4+, Lyt-2- T cell clones were isolated and expanded by standard techniques . The clones themselves protected mice from listerial challenge when injected intravenously, and supernatants generated from Ag-stimulated clones were protective . In order to define factors important in the protection, supernatants from the clones were assayed for CSF by several in vitro assays . Total colony-stimulating activity was measured with a bone marrow colony-forming assay . T cell clones secreted 1000 to 2000 U/ml of colony-stimulating activity after 48 hours of stimulation with specific antigen . The relative amounts of the various CSF were determined by the capacity of supernatants to support proliferation of the factor-dependent cell lines FDCP-1 and 32D cl 3 in the presence and absence of specific anti-CSF antibodies . Results showed that most of the CSF activity was due to granulocyte-macrophage (GM)-CSF and IL-3 . The role of GM-CSF in anti-listerial host resistance was assessed in two types of experiments . In one set of experiments GM-CSF activity was neutralized in the supernatants by addition of specific rabbit anti-GM-CSF antibodies . Treated and untreated supernatants were then tested for their capacity to protect nonimmune mice against listerial challenge . Neutralization of GM-CSF in the supernatants decreased the protective capacity of the supernatants by approximately 23% . In a second set of studies, the administration of recombinant murine GM-CSF was shown to protect mice from challenges of L . monocytogenes . Taken together, these experiments provide evidence that CSF are important mediators of immune T cell mediated host defenses.

Am J Reprod Immunol, 1989 Oct, 21(2), 61 - 6
Effects of mouse testicular extract on immunocompetent cells; Emoto M et al.; We investigated mouse testicular extract (TE) to clarify its biological functions in reproductive immunity . TE, at concentrations of 50-300 micrograms/ml, enhanced macrophage activities of spreading, glucose consumption, and cytostasis against a susceptible tumor cell line . On the other hand, TE inhibited concanavalin A (Con A)-induced T-cell blastogenesis in the dose range of 10-600 micrograms/ml . To elucidate the origin of TE, W/Wv mice, which genetically lack germ cells, were used . TE obtained from W/Wv mice enhanced the spreadability of macrophages and inhibited Con A-induced blastogenesis of T cells . The enhancement of macrophage spreading was only achieved by the interstitial fluid (IF), while the suppression of Con A-induced T-cell responses was detected in seminiferous tubule fluid (STF) as well as in IF . TE did not affect listerial antigen-specific responses of lymphocytes in vitro . These results suggest that TE has the capacity to regulate the biological responses associated with reproduction.

J Med Microbiol, 1989 Oct, 30(2), 119 - 27
Separation and properties of the haemolysins and extracellular enzymes of Listeria monocytogenes and L . ivanovii; Barclay R et al.; Desalted ammonium-sulphate (0-65%) precipitates from the cell-free supernates of 16-24-h cultures of Listeria monocytogenes Boldy and L . ivanovii (previously L . monocytogenes) Type 5 were eluted through Sephadex G-200 . The enzyme activities gave rise to two main peaks . The first peak (approximate mol . wt of protein 150,000) contained only phosphatase activity (assayed by hydrolysis of 4-nitrophenylphosphate at pH 5.0 and 7.0) . The second peak (approximate mol . wts of proteins 40,000-60,000) contained the haemolysin activity and the following hydrolytic activities (assay substrates are given in parentheses): phospholipase C (phosphatidyl choline and 4-nitrophenyl-phosphoryl-choline); phosphodiesterase (bis-4-nitrophenyl-phosphate); acid phosphatase (4-nitrophenylphosphatase); and esterases and lipases (4-nitrophenyl acetate, naphthyl-acetate and -oleate, triacetin and triolein) . DEAE-Sephadex chromatography of appropriate fractions from the Sephadex G-200 purification step separated the first peak into two phosphatases and resolved the second peak into its constituent activities . Polyacrylamide gel electrophoresis showed that the individual fractions from the DEAE-Sephadex step consisted of mixtures of protein . The effects of pH and potential activators and inhibitors on the active proteins purified by DEAE-Sephadex chromatography were examined.

Enferm Infecc Microbiol Clin, 1989 Oct, 7(8), 424 - 7
{Listeriosis in the adult: presentation of 14 cases}; Ferrer D et al.; The incidence of Listeria monocytogenes (LM) infection has increased in recent years, particularly in immunocompromised patients or in those with severe underlying diseases . However, it still is an unusual pathogen . In the present study we report 14 cases of listeriosis in adults, seen from 1978 to 1988 . The organism was isolated from the blood in 10 instances, from cerebrospinal fluid in 5, and from a cervical abscess in one . The ages of the patients ranged from 29 to 81 years and there was a clear male predominance . In all cases except in one there was a previous underlying disease, and four had received immunosuppressant therapy . Listeria monocytogenes was sensitive to ampicillin, erythromycin, vancomycin, gentamicin, rifampicin, ticarcillin, azlocillin, mezlocillin and tetracyclines.

Mol Biol Med, 1989 Oct, 6(5), 463 - 74
Listeria monocytogenes . A model system for the molecular study of intracellular parasitism; Cossart P et al.; Listeria monocytogenes is a facultative intracellular bacterium which, in its mammalian host, can infect enterocytes and mononuclear phagocytes . It is responsible for severe infections in humans and animals . Recovery from infection and resistance depends on the development of a T-cell response, antibodies not being protective . Several features of L . monocytogenes make it particularly suitable for the study of genetic and molecular aspects of invasion and intracellular parasitism . First, L . monocytogenes not only multiplies rapidly in bacterial broth but also easily infects macrophages and other cells in culture . Second, since it infects primarily immunocompromised individuals or pregnant women, its manipulation does not require extensive containment . Third, the genus Listeria includes several nonpathogenic species, facilitating the identification of species-specific genes and products required for pathogenicity . This identification is now possible due to the parallel development of powerful genus-specific genetic tools (transposons, plasmids, genetic transformation) and improvement of recombinant DNA techniques . Finally, the in vivo relevance of the putative virulence genes or gene products can be tested in the experimental murine infection, which has already proved invaluable in the study of the induction and expression of T-cell-mediated immune response . This review discusses current knowledge concerning these particular features, with an emphasis on listeriolysin O, a major virulence factor, and the only bacterial gene product known to be absolutely required for intracellular growth.

Immunobiology, 1989 Oct, 179(4-5), 328 - 41
The effect of T cell depletion from spleen cell allografts on graft-versus-host disease and long-term immune reconstitution in H-2 haplotype-identical murine combinations; Tokuda N et al.; Graft-versus-host disease (GVHD) and states of immune reconstitution in allogeneic chimera mice across minor histocompatibility antigens were analyzed in excess of 9 months after injecting AKR/JSea (AKR) spleen cells into irradiated C3H/HeSlc (C3H) mice . When T cell-depleted AKR spleen cells were used as inoculum cells, neither graft failure nor GVHD was seen for 9 months postgrafting in the C3H mice irradiated with 660 rad or more . In an AKR - C3H (850 rad) model, Thy1.1+ or L3T4+ T cell depletion from donor AKR spleen cells abolished both acute and chronic GVHD in lethally irradiated C3H mice . Lyt2+ T cell depletion, however, resulted in acute and chronic GVHD in more than half of the recipient C3H mice . Moreover, actual existence of donor (AKR)-type T cells with L3T4 phenotype, but not Lyt2 phenotype, was always observed in the spleen of the C3H mice suffering from acute GVHD . In addition, the C3H mice that were irradiated with 850 rad, grafted with AKR spleen cells depleted of Lyt2.1+ T cells, escaped from acute GVHD and survived for more than 10 mo postgrafting, showed impaired activities of immune responses such as delayed footpad reaction to sheep red blood cells, antibody production tested by IgM plaque forming cells and reactivity to an intracellular bacterium . Listeria monocytogenes as compared with the C3H mice reconstituted with syngeneic C3H spleen cells or Thy1.1+ or L3T4+ T cell-depleted AKR spleen cells . These results suggest that L3T4+ T cells, rather than Lyt2+ T cells, contained in the grafted cells not only cause acute GVHD but also a long-term immunodeficient state (chronic GVHD) in recipient mice in the H-2-identical murine combinations examined here.

Aust N Z J Med, 1989 Oct, 19(5), 486 - 7
Hepatic involvement in listeriosis; Gebauer K et al.; We report an adult with listeriosis . Sequential liver biopsies demonstrated the resolution of associated granulomas and microabscesses after the administration of high doses of penicillin for ten days . This observation has not previously been reported.

Nebr Med J, 1989 Oct, 74(10), 303 - 5
Listeria monocytogenes peritonitis in a patient on continuous ambulatory peritoneal dialysis; Allais JM et al.; We report a case of peritonitis in a patient on continuous ambulatory peritoneal dialysis caused by Listeria monocytogenes . The patient was taking oral corticosteroids for underlying systemic lupus symptoms, and had classic signs and symptoms of peritonitis . There was initial clinical deterioration while in vitro data indicating that the organism was sensitive to vancomycin with a minimum inhibitory concentration of 0.5 micrograms/ml . The patient rapidly responded to intravenous ampicillin . We believe this to be the second reported case of L . monocytogenes peritonitis in a CAPD patient.

J Med Microbiol, 1989 Oct, 30(2), 111 - 8
Haemolysins and extracellular enzymes of Listeria monocytogenes and L . ivanovii; Barclay R et al.; Of 120 laboratory-maintained strains of Listeria monocytogenes and two of L . ivanovii examined for haemolytic and lipolytic activity, 62 exhibited haemolytic activity alone, 20 of these showed haemolytic and lipolytic activity and 40 had neither activity . The L . ivanovii strains showed both activities . The results indicated a relationship between haemolysin production and lipolytic activity which was not explained by the serotype of the organism . In addition, the following hydrolytic activities were detected in the cell-free growth media of strains L . monocytogenes Boldy and L . ivanovii (formerly L . monocytogenes) Type 5 (substrates acted upon are given in parentheses): acid phosphate (4-nitrophenylphosphate, naphthyl phosphate, glycerophosphate, phosphorylcholine and GTP); neutral phosphatase (4-nitrophenylphosphate, naphthyl phosphate, phosphorylcholine, NADP and UDPG); phosphodiesterase (bis-4-nitrophenylphosphate, ATP and NADP); NADase (NAD); phospholipase C (4-nitrophenylphosphoryl-choline, phosphatidyl choline and ethanolamine, and sphingomyelin); and lipase and esterase (triacetin, tributyrin, triolein, naphthyl-laurate,-myristate,-caprylate,-palmitate and -oleate, 4-nitrophenyl-acetate-laurate and Tween 80) . The preparations also showed weak catalase activity . No evidence was found for the presence of RNAase, DNAase, peptidase/amidase, phosphoamidase, alpha-amylase, glucosidase, galactosidase, pyranosidase or glucose aminidase.

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