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 . Al