J Clin Microbiol, 1986 Oct, 24(4), 661 - 4 Evidence for production of an enterotoxin and cholera toxin cross-reactive factor by Aeromonas hydrophila; Chopra AK et al.; The enterotoxins produced by Aeromonas hydrophila were examined for biological activity by the rabbit ileal loop and suckling mouse assays, as well as by elongation of CHO cells . Antigenic evaluation of the culture filtrates from various isolates of A . hydrophila was performed by enzyme-linked immunosorbent assay with anti-cholera toxin and anti-Aeromonas enterotoxin . Heat stability data demonstrated the presence of a heat-labile cholera toxin cross-reactive factor and a heat stable non-cholera toxin cross-reactive enterotoxin . The biological activities of both enterotoxins were heat labile at 56 degrees C for 20 min. Can J Microbiol, 1986 Oct, 32(10), 814 - 9 Melanogenesis in murine B16 cells exposed to Aeromonas hydrophila cytotoxic enterotoxin; Bunning VK et al.; Specific markers (growth, melanogenesis) of B16 murine melanoma cells in culture were used as indicators of toxin production by Aeromonas hydrophila . Cytotonic enterotoxinlike activity (inhibited growth, raised tyrosinase activity, and melanin accumulation) occurred at cytotoxic end points of purified beta-hemolysin and several culture filtrates . Antihemolysin rabbit serum inhibited this activity . A hemolysin-neutralized culture filtrate concentrate (10X) failed to elevate tyrosinase relative to untreated and cholera toxin treated controls . Similar dilution profiles using Chinese hamster ovary cells showed limited cell extension only at cytotoxic end points with antihemolysin inhibiting this activity . Cytotoxicity of Chinese hamster ovary cells and B16 cells was proportional to hemolytic activity, with B16 cells showing about 100-fold greater sensitivity on a per cell basis . Cell culture cytotoxicity attributed to beta-hemolysin correlated with reactivity in rabbit ileal loop assays . The ADP-ribosyl transferase activity of concentrated (10X) A . hydrophila culture filtrates and fractions thereof was negative . Apparently sublethal doses of A . hydrophila beta-hemolysin can nonspecifically stimulate cyclic adenosine monophosphate mediated events in melanoma and Chinese hamster ovary cell assays, producing lower activities than cholera toxin with shorter lag times. Hepatogastroenterology, 1986 Aug, 33(4), 187 - 90 New unusual forms of colitis . Report of four cases with known and unknown etiology; Bayerdorffer E et al.; Four patients with colitis, in two of whom the etiology was unknown, are presented . One patient with discontinuous segmental colitis was infected by Aeromonas hydrophila, and another with presumed idiopathic inflammatory bowel disease was superinfected by this pathogen . Although Aeromonas hydrophila has been known as a rare cause of diarrhea in our region, it is in the first instance reported to cause severe long-lasting colitis as well as superinfection of idiopathic inflammatory bowel disease (IIBD) . Another patient presented with segmental ischemic colitis which was rather atypical and of unknown etiology; the patient was young and had no predisposing factors for vascular occlusive disease . The fourth patient with long-lasting segmental granulomatous colitis which was suspected to be parasitic in origin remained without a definitive diagnosis . This presentation of patients with endoscopically proven colitis should in view of our increasing knowledge of colitis remind us to keep a look out for new infections and other forms of inflammatory bowel disease. J Clin Microbiol, 1986 Aug, 24(2), 228 - 32 Purification and characterization of an Aeromonas hydrophila hemolysin; Asao T et al.; A hemolysin produced by Aeromonas hydrophila CA-11, isolated from an environmental source, was purified by sulfopropyl-Sephadex C-25 chromatography at pH 5.0 . This hemolysin caused fluid accumulation in infant mouse intestines and rabbit intestinal loops and killed Vero cells, as did the hemolysin produced by strain AH-1, isolated from a diarrheal case . In polyacrylamide gel electrophoreses at pHs 4.0 and 9.4 and in thin-layer isoelectric focusing, CA-11 hemolysin migrated as a single band to a position different from that of AH-1 hemolysin . Immunodiffusion tests indicated that CA-11 hemolysin was immunologically related to AH-1 hemolysin but possessed unique antigenic determinants . Neutralization tests with antihemolysin sera also demonstrated immunological cross-reactivity between AH-1 and CA-11 hemolysins . These results apparently indicate that the hemolysins produced by the two strains of A . hydrophila are immunologically and physicochemically different from each other. J Med Microbiol, 1986 Aug, 22(1), 51 - 5 Biochemical characteristics, enterotoxigenicity and susceptibility to antimicrobial agents of clinical isolates of Aeromonas species encountered in the western region of Saudi Arabia; Gosling PJ; The biochemical characteristics, enterotoxigenicity and susceptibility to antibiotics are reported for 22 strains of Aeromonas species isolated from clinical specimens in the Western Region of Saudi Arabia . Aeromonas caviae was the species most frequently observed; a high proportion of these strains fermented lactose, whereas lactose fermentation was not observed in strains of A . hydrophila and A . sobria . Enterotoxigenicity, as judged by cytotoxicity in tissue culture was observed in three of four A . hydrophila strains and six of seven A . sobria strains, but in only one of 11 A . caviae strains . Two schemes for the biochemical assessment of enterotoxigenicity were found to be in 91% and 86% agreement respectively with cytotoxicity studies and in 95% agreement with each other . No single biochemical test correlated fully with enterotoxigenicity, but 86% of strains that oxidized gluconate produced a cytotoxin . Most strains were inhibited by concentrations of gentamicin, amikacin, chloramphenicol and tetracycline achievable in plasma . Most strains were resistant to broad-spectrum penicillins and many were also resistant to cefuroxime and cefoxitin. Surgery, 1986 Aug, 100(2), 214 - 21 Thromboxane A2 mediates hemodynamic and respiratory dysfunction in graded bacteremia; Slotman GJ et al.; Thromboxane A2 has been implicated as a mediator of cardiorespiratory dysfunction in sepsis . This study evaluated whether or not thromboxane A2 was necessary or sufficient for these adverse effects to occur during bacteremia . Fourteen adult swine under barbiturate anesthesia and breathing room air were monitored with arterial and pulmonary artery catheters . Animals were studied for 4 hours in three groups: group I, graded infusion of 10(9)/ml Aeromonas hydrophila; group II, Aeromonas hydrophila infusion plus SQ 29,548 (thromboxane A2 antagonist); and group III, U46619 (thromboxane A2 agonist) infusion in normal swine to pulmonary artery pressures observed in group I . Hemodynamic parameters, arterial and mixed venous blood gases, and plasma thromboxane B2 and prostaglandin 6-keto-F1 were measured . At sacrifice after 4 hours, wet-to-dry lung weights were calculated . Results indicated that thromboxane A2 was necessary and sufficient for the development of pulmonary hypertension and impaired alveolar-capillary oxygen diffusion in graded bacteremia . It was necessary but not sufficient for increased lung water to occur and sufficient but not necessary for decreased cardiac index and stroke volume index . Thromboxane A2 was neither sufficient nor necessary to the pathophysiology of systemic hypotension during graded bacteremia . Plasma prostaglandin 6-keto-F1 levels were increased in hypotensive animals with sepsis, suggesting its involvement in hypotension during sepsis. Mol Gen Genet, 1986 Aug, 204(2), 289 - 95 Molecular cloning and expression in Escherichia coli of the structural gene for the hemolytic toxin aerolysin from Aeromonas hydrophila; Howard SP et al.; The structural gene for the hemolytic toxin aerolysin has been cloned into the plasmid vectors pBR322 and pEMBL8+ . The gene was localized on the hybrid plasmids by analysis of plasmids generated by transposon mutagenesis . The sequence of the first 683 bases of an insert in pEMBL8+ was determined and shown to encode the amino terminus of the protein as well as a typical signal sequence of 23 amino acids . Aerolysin is produced by E . coli cells containing the cloned aerolysin gene and it is processed normally by removal of the signal sequence, however it is not released from the cell . The protein appears to be translocated across the inner membrane of E . coli as its signal sequence is removed and the processed protein can be released by osmotic shock. J Bacteriol, 1986 Jul, 167(1), 368 - 74 Cloning, expression, and mapping of the Aeromonas hydrophila aerolysin gene determinant in Escherichia coli K-12; Chakraborty T et al.; DNA sequences corresponding to the aerolysin gene (aer) of Aeromonas hydrophila AH2 DNA were identified by screening a cosmid gene library for hemolytic and cytotoxic activities . A plasmid containing a 5.8-kilobase EcoRI fragment of A . hydrophila DNA was required for full expression of the hemolytic and cytotoxic phenotype in Escherichia coli K-12 . Deletion analysis and transposon mutagenesis allowed us to localize the gene product to 1.4 kilobases of Aeromonas DNA and define flanking DNA regions affecting aerolysin production . The reduced hemolytic activity with plasmids lacking these flanking regions is associated with a temporal delay in the appearance of hemolytic activity and is not a result of a loss of transport functions . The aerolysin gene product was detected as a 54,000-dalton protein in E . coli maxicells harboring aer plasmids and by immunoblotting E . coli whole cells carrying aer plasmids . We suggest that the gene coding aerolysin be designated aerA and that regions downstream and upstream of aerA which modulate its expression and activity be designated aerB and aerC, respectively. J Gen Microbiol, 1986 Jul, 132 ( Pt 7), 1975 - 9 Characterization of extracellular metallo- and serine-proteases of Aeromonas hydrophila strain B51; Nieto TP et al.; The extracellular proteases of Aeromonas hydrophila B51 were stable on heating (56 degrees C) and on storage at 4 degrees C or -20 degrees C . Inhibitor studies showed that 72% of the total activity was inhibited by EDTA (a metalloprotease inhibitor) and 26% was inhibited by phenylmethanesulphonyl fluoride (a serine protease inhibitor) . Analytical isoelectric focussing revealed the presence of 33 proteins in the crude extracellular products . Using a casein overlay technique three separate zones of proteolytic activity were detected: a zone with pI 6.5-6.8, formed of two closely focussed bands (possibly isomers of the same protease) and completely inhibited by EDTA; a single band with pI 7.0, which was inhibited by EDTA; and a diffuse zone with pI 8.3-8.5, which was only partially inhibited by EDTA . It is concluded that the serine protease activity focussed in this latter zone . These results indicate the presence of at least four, and possibly five proteases . Our results differ substantially from those reported by other workers using different isolates and it is suggested that significant differences in the character of extracellular products and extracellular proteases exist between different isolates of A . hydrophila. Vet Immunol Immunopathol, 1986 Jun, 12(1-4), 345 - 50 Protective efficacy of Aeromonas hydrophila vaccines in nile tilapia; Ruangpan L et al.; Protection and serum antibody production against Aeromonas hydrophila was examined in nile tilapia, Tilapia nilotica (L.) . Intraperitoneally injected formal in-killed and Freunds complete adjuvant vaccines were compared using different doses (2.9 X 10(7) and 2.9 X 10(9) cfu/ml) . Upon challenge, the protective ability and antibody titers resulting were significantly different between vaccinated and unvaccinated groups . A relative level of protection of 100% was obtained within two-weeks, and a maximum level of 53-61% protection was found one-week post-vaccination. Vet Immunol Immunopathol, 1986 Jun, 12(1-4), 339 - 44 Surface antigens of virulent strains of Aeromonas hydrophila; Dooley JS et al.; Antiserum was raised in rabbits to whole cells of a representative strain from a group of A . hydrophila strains exhibiting enhanced virulence for fish . The major surface antigens of the strain were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting . The lipopolysaccharide (LPS) was examined using SDS-PAGE and silver staining . It was found to possess O polysaccharide chains of homogeneous length that were highly immunogenic . The LPS was conserved both morphologically and antigenically throughout the high virulence group . Heat-labile protein antigens were detected after absorption of the antiserum with boiled cells of the homologous strain . Only one major protein antigen, with a molecular weight of approximately 52,000, was present in outer membrane preparations or in whole cell lysates . A representative strain from the high virulence group, strain TF7, was shown by electron microscopy to be covered by a regular surface protein array (S-layer) which was found to be composed primarily of the 52 KD protein antigen . All the other members of the A . hydrophila high virulence group were shown to possess similar S-layers. Vet Immunol Immunopathol, 1986 Jun, 12(1-4), 331 - 8 Does Aeromonas salmonicida affect the immune system of carp, Cyprinus carpio L.? Pourreau CN, Evenberg D, de Raadt WM, van Mechelen JA, van Muiswinkel WB. Aeromonas salmonicida is a significant bacterial pathogen of cyprinid and salmonid fishes causing the systemic disease furunculosis . Several observations led us to believe that A . salmonicida was able to evade or suppress the immune system of the fish: injection of whole bacteria or surface antigens was unsuccessful at protecting fish against lethal challenges; memory did not develop in survivors of sublethal infections; diseased fish often carried other opportunistic bacterial pathogens in addition to A . salmonicida, and serum protein and particularly immunoglobulin significantly decreased during A . salmonicida infections . We tested the ability of fish sublethally infected with virulent and avirulent A . salmonicida to mount a humoral immune response to sheep erythrocytes and found fewer plaque forming cells in the pronephros and lower serum anti-SRBC antibodies in infected fish as compared to controls . We also monitored the cellular immune response of diseased fish by skin allograft rejection and found an enhancement of the response that increased as the disease progressed . However, the extend of inflammation was reduced in infected fish as compared to non-infected animals . At this moment these preliminary observations are difficult to explain . Our future research will focus more specifically on cell populations that may be affected by A . salmonicida. Vet Immunol Immunopathol, 1986 Jun, 12(1-4), 321 - 30 Blood changes in carp (Cyprinus carpio) induced by ulcerative Aeromonas salmonicida infections; Evenberg D et al.; Only recently Aeromonas salmonicida has been recognized as a significant bacterial pathogen in ulcerative disease of cyprinid fish . Our attempts to formulate a vaccine based on bacterial surface antigens were unsuccessful in conferring reliable protection against lethal challenge . This lead us to study pathological changes in the humoral defense system during ulcerative A . salmonicida infection in carp . High numbers of opportunist pathogens such as A . hydrophila and Pseudomonas sp . were frequently recovered from the internal organs of moribund fish, in addition to A . salmonicida . These findings together with leucopenia in moribund fish suggest that pathogenesis is characterized by a state of immune suppression . In addition, fish which had sustained a sublethal infection were not protected against a subsequent lethal challenge . However, fish previously injected with a concentrated and inactivated culture supernatant showed protection . Differential blood cell counts did not differ between experimental and control groups during sublethal infection in contrast to serum proteins . Furthermore infected non-immune carp showed a progressive decrease of immunoglobulin and total serum protein levels before the day of peak mortality whereas protected carp maintained the immunoglobulin concentration despite a decrease in protein . Our observations suggest the involvement of multiple pathogenic events, affecting different parts of the humoral defense system during ulcerative A . salmonicida infection . The immunosuppressive effects can be minimized by prior vaccination with culture supernatant. Vet Immunol Immunopathol, 1986 Jun, 12(1-4), 287 - 96 Effect of an immunopotentiator on Aeromonas salmonicida infection in rainbow trout (Salmo gairdneri); Kitao T et al.; The immunoactive peptide FK-565 (heptanoyl-y-D-glutamyl-(L)-mesodiaminopimelyl-(D)-alanine) was found to induce protection against intraperitoneal Aeromonas salmonicida infection in rainbow trout (Salmo gairdneri Richardson) . The survival rate was as high as 60% when FK-565 was given intraperitoneally as a single dose (1mg/kg) one day before bacterial challenge . A non-specific stimulation of phagocytic cells by FK-565 at an early stage of the bacterial infection may contribute to the resistance observed . The phagocytic activity of peritoneal phagocytic cells as well as phagocytic cells of the pronephros were stimulated by FK-565 in vivo and in vitro, respectively, as compared to untreated control fish . Furthermore, decreased activity of phagocytic cells previously immunosuppressed with cyclophosphamide was rapidly restored by application of FK-565. Vet Immunol Immunopathol, 1986 Jun, 12(1-4), 223 - 34 Interaction between Aeromonas salmonicida and peritoneal macrophages of brook trout (Salvelinus fontinalis); Olivier G et al.; The phagocytic and bactericidal properties of peritoneal macrophages obtained from brook trout (Salvelinus fontinalis), injected with either glycogen or a modified Freund's complete adjuvant (MFCA), were evaluated against an avirulent and a virulent strain of Aeromonas salmonicida . Avirulent bacteria were effectively phagocytized and killed by macrophages obtained from fish injected with both irritants . With glycogen-elicited macrophages, no enhancement of killing was observed following opsonization of avirulent bacteria with specific antibodies . A killing index (K.I.) of 38 was obtained, compared to a K.I . of 39 for unopsonized bacteria . When avirulent bacteria were opsonized with complement, the K.I . was increased to 67 . Virulent bacteria were less susceptible to the phagocytic and the bactericidal activities of glycogen-elicited macrophages, even after opsonization with antibodies and/or complement, K.I . of 9 to 15 . In contrast, MFCA-elicited macrophages showed increased phagocytic and bactericidal activities against both strains . The K.I . of unopsonized virulent bacteria was increased to 47 and 46 compared to K.I . of 4 and 7 obtained with glycogen-elicited macrophages. Eur J Clin Microbiol, 1986 Jun, 5(3), 311 - 6 Incidence and virulence of Aeromonas species in feces of children with diarrhea; Megraud F; Aeromonas spp . occurring in feces of children with diarrhea were studied . Forty-eight strains were isolated from 2,025 specimens during a one year period . Only 11 of 44 strains tested yielded virulence factors (cytotoxin, hemolysin and hemagglutinin) . Six strains were identified as Aeromonas sobria and five as Aeromonas hydrophila . The other strains isolated were identified as Aeromonas caviae . The biochemical characteristics associated with virulence factors were a positive Voges-Proskauer reaction, production of gas from glucose, fermentation of mannose, and absence of beta-lactosidase . Beta-D-glucosidase and esculin hydrolysis were the main characteristics used to differentiate Aeromonas sobria from the other two species . The incidence of Aeromonas spp . with virulence factors in feces of children with diarrhea would seem to vary widely from one area to another. J Med Microbiol, 1986 Jun, 21(4), 319 - 24 Partial characterisation of a soluble haemagglutinin from human diarrhoeal isolates of Aeromonas; Stewart GA et al.; A soluble haemagglutinin has been identified in cell-free culture supernates of human diarrhoeal isolates of Aeromonas sobria, A . hydrophila and A . caviae . It was oligomeric; a major peak of haemagglutinating activity had an apparent mol . wt of 780,000 but there was haemagglutinating activity throughout the mol . wt range less than 40,000- greater than 10(6) . Human group O, A and B, horse, rabbit, chicken and rat erythrocytes, but not those of sheep and cow, were agglutinated by the soluble haemagglutinin, in contrast to the cell-bound agglutinin . Agglutination was inhibited by fetuin, a complex glycoprotein, but not by simple sugars . The haemagglutinating activity was not affected by 0.5 M NaCl, dithiothreitol or the presence or absence of Ca++ . It was unrelated to the haemolytic, enterotoxigenic and proteolytic activities present in cell-free extracts of A . sobria . All A . sobria, 73% of A . hydrophila and 68% of A . caviae strains tested produced this soluble haemagglutinin . A . caviae does not appear to be an enteric pathogen, therefore this soluble haemagglutinin alone is unlikely to be a virulence factor in Aeromonas spp. J Clin Microbiol, 1986 Jun, 23(6), 1140 - 2 Production of "Asao toxin" by Aeromonas strains isolated from feces and drinking water; Notermans S et al.; Cultures of Aeromonas species were tested for production of a toxin recently purified by Asao et al . (T . Asao, Y . Kinoshita, S . Kozaki, T . Uemura, and G . Sukaguchi, Infect . Immun . 46:122-127, 1984) and described as a hemolysin with enterotoxic and cytotoxic activity . The toxin was produced by only 63% of Aeromonas sobria strains and by 93% of Aeromonas hydrophila strains . Also, 54% of A . hydrophila strains produced another cytotoxic entity. J Clin Microbiol, 1986 Jun, 23(6), 1065 - 7 Growth of Aeromonas species on enteric agars; Desmond E et al.; The efficacy of eight routine enteric agars for supporting the growth of 32 strains of Aeromonas spp . (17 A . hydrophila strains, 8 A . sobria strains, and 7 A . caviae strains) was investigated . The plating efficiency of Aeromonas spp . on these media varied greatly (range, 0 to 100%), as did their colony size when compared with that on noninhibitory medium (5% sheep blood agar) . Plating efficiency on seven of these eight media appeared to be strain- and not species dependent . Overall, eosin-methylene blue and Hektoen enteric agars showed low plating efficiencies for A . hydrophila, whereas both A . sobria and A . caviae were severely inhibited on brilliant green agar . When all these species are considered collectively, deoxycholate, MacConkey, and xylose lysine deoxycholate appeared to be the most satisfactory routine agars for Aeromonas spp . recovery when used in conjunction with blood agar. J Clin Microbiol, 1986 Jun, 23(6), 1026 - 9 Phenotypic characteristics of Aeromonas species isolated from adult humans; George WL et al.; The phenotypic characteristics of 89 Aeromonas strains, most of which had been isolated from feces, were examined . Eighty-two percent of the isolates could be placed into one of four groups on the basis of five tests . The relationship of these groups to the three motile species of Aeromonas (Aeromonas caviae, A . hydrophila, and A . sobria) that have been isolated from humans is unclear . Because the means for identification of Aeromonas strains to the species level appear to be imprecise and because the role of each of these species in human diarrhea is unclear at this time, we recommend that identification of enteric Aeromonas isolates to the species level not be done routinely. Antimicrob Agents Chemother, 1986 Jun, 29(6), 992 - 6 Multiple low-level antibiotic resistance in Aeromonas salmonicida; Wood SC et al.; Mutants with multiple low-level antibiotic resistance were isolated from virulent wild-type Aeromonas salmonicida strains exposed to a low concentration of any one of several low-molecular-mass (approximately 635 daltons or less) antibiotics . Multiple resistance was toward beta-lactam compounds (penicillin G, ampicillin, cloxacillin), quinolones (flumequine, oxolinic acid, nalidixic acid), tetracyclines, chloramphenicol, and novobiocin . Susceptibilities of the mutants toward several higher-molecular-mass (greater than 700 daltons) hydrophobic or polycationic antibiotics such as rifampin, erythromycin, polymyxin B, and streptomycin sulfate were not affected . The mutants were obtained at frequencies suggesting point mutations . Outer membrane protein profiles, examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, revealed that all multiple low-level resistant mutants were deficient in a major protein of approximately 38.5 kilodaltons and contained a major protein of approximately 37 kilodaltons which was not present in significant amounts in the wild-type strains . In addition, these mutants lacked exoprotease activity . Furthermore, mutants isolated as deficient in exoprotease were found, with the exception of one avirulent strain, to exhibit multiple low-level antibiotic resistance and the outer membrane protein changes. Appl Environ Microbiol, 1986 Jun, 51(6), 1343 - 9 Electrostatic mechanism of survival of virulent Aeromonas salmonicida strains in river water; Sakai DK; The ecological mechanism of survival of Aeromonas salmonicida, the bacterial pathogen of fish furunculosis, in river water was investigated by laboratory-based experiments with two virulent strains (which were autoagglutinating) and two virulent strains (which were nonagglutinating) . A difference in net electrical charge of A . salmonicida cells was detected by electrophoresis; cells of the virulent strains were negative, whereas cells of the avirulent strains were positive . Despite the loss of viable cells within a week in distilled water and physiological saline (0.85% sodium chloride), the cells of the virulent strains survived for more than 15 weeks in the presence of diluted humic acid (10 micrograms/ml), tryptone (10 micrograms/ml), and cleaned river sand (100 g/100 ml of medium), but loss of viable cells occurred within 5 weeks in the absence of sand . The cells of the avirulent strains lost viability within 2 weeks with no relation to the presence of sand . Using ion-exchange columns, humic acid and the amino acids of tryptone were found to be anionic and cationic in water (pH 7.0), respectively . Sand particles had a high capacity to adsorb humic acid alone and amino acid-humic acid complexes . Thirty to fifty times the environmental concentration of amino acids (10 micrograms/ml) were accumulated on the surface of sand particles, thereby permitting only bacterial cells carrying net negative electrical charges (virulent cells) to survive for a long period on the surface of the sand particles . These electrostatic interrelationships among river sand, humic acid, and bacterial cells are closely implicated in the mechanism of long-term survival of virulent A . salmonicida in river sediments. Vet Immunol Immunopathol, 1986 Jun, 12(1-4), 93 - 105 The ontogeny of humoral immunity in rainbow trout, Salmo gairdneri; Tatner MF; The ontogeny of the humoral immune response to a 'thymus dependent' and a 'thymus independent' antigen, human gamma globulin (HGG) and Aeromonas salmonicida (AS) respectively, was investigated in the fry of rainbow trout, Salmo gairdneri, by direct immersion vaccination in the antigens (dose 5 mg/L HGG; 10(8) cells/ml AS; 30 minutes) at known ages/weights from 7 days post hatch, and at 1, 2, 3, and 4 months post hatch . Half the fry in each group were tested for antibodies 4 weeks after vaccination, the remainder were reimmunised and tested again after a further 4 weeks . Appropriate controls to test for tolerance induction and memory responses were included . The results indicate that fry are capable of mounting a humoral immune response very early in ontogeny . There is a period of 'unresponsiveness' which persists for longer against HGG, than against AS, though it was not thought to be tolerance as such . Memory could be detected to HGG in fry given a first immunisation at 2 months . The results are compared with preliminary experiments in which fry were first thymectomised 4 weeks before the first immunisation . In fry thymectomised at 1 month post hatch, and tested for primary and secondary responses at 2 and 3 months, the primary response to HGG is unaltered, but the secondary response is reduced . Both the primary and secondary response to AS is unaltered . When thymectomy is performed later, the effect on the secondary response to HGG is no longer apparent, but the primary response to AS is slightly reduced. Vet Immunol Immunopathol, 1986 Jun, 12(1-4), 181 - 92 Effects of direct immersion in antigen on immunological memory in young carp, Cyprinus carpio; Mughal MS et al.; The study asks whether, in fish, antigens encountered early in life can prime the immune system to yield memory responses on subsequent challenge with the same antigen and, if so, whether positive immunity or immunological tolerance is induced . The direct immersion method of vaccination was used to prime 4 week old carp, Cyprinus carpio, and was compared with priming by injection . Three different forms of antigen were used: the thymus dependent antigen, human gamma globulin (HGG) in soluble and in particulate (latex bound) form; also the putative thymus independent bacterin, formalin-killed Aeromonas salmonicida . The thymus dependent antigens were also used on 9 month old animals . In 4 week old carp, A . salmonicida vaccine delivered either by direct immersion or intraperitoneally (i.p.) yielded enhanced serum antibody levels and heightened proliferative responses in the lymphoid tissue of the spleen and kidney . Latex-bound HGG applied by direct immersion was found to partially suppress secondary antibody production while still eliciting enhanced proliferation . The decrease in antibody production following direct immersion priming of young fish with latex-bound HGG was not nearly as marked as the tolerance induced following priming with latex-bound HGG by the i.p . route and, unlike the tolerance induced by the injection route, may possibly still occur in older fish . When HGG was applied to young carp in soluble form by direct immersion it was ineffective and failed to influence memory induction . This is in contrast to the antibody tolerance, accompanied by an enhanced proliferative response following challenge, which resulted from administration of the soluble antigen by injection in the young fish . The status of the immune system in these antibody-tolerant fish is still far from clear . This highlights the need for further investigation of the role of cell-mediated reactions and local immunity in the immune responses of fish. Appl Environ Microbiol, 1986 Jun, 51(6), 1309 - 13 Differential partition of virulent Aeromonas salmonicida and attenuated derivatives possessing specific cell surface alterations in polymer aqueous-phase systems; Van Alstine JM et al.; Two-polymer aqueous-phase systems were used to compare via partitioning the surface properties of strains of the fish pathogen Aeromonas salmonicida which differed in their ability to produce the surface protein array known as the A layer and in their ability to produce smooth lipopolysaccharide . In these two-phase systems, biological particles are known to partition between the phases in a manner related to a variety of surface properties, including hydrophobicity, charge, and lipid composition . Both the presence of the superficial protein layer and the O polysaccharide chains of lipopolysaccharide were shown to play an important role in the partitioning behavior of A . salmonicida cells . The presence of the A layer, which is crucial to the virulence of A . salmonicida, appeared to decrease the surface hydrophilicity of this pathogen and to increase, in a somewhat specific manner, its surface affinity for fatty acid esters of polyethylene glycol . The ability of two-polymer aqueous-phase systems to differentially partition A . salmonicida cells on the basis of differences in surface architecture suggests their general usefulness for the analysis of surface properties important in bacterial virulence and should permit their use in the selection of strains and mutants exhibiting specific surface characteristics. Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi, 1986 May, 19(2), 124 - 36 Comparative study of the biotype, hemolysin-producing capability and antibiogram of the aquatic and the clinical strains of Aeromonas hydrophila; Tsai WC et al.; One hundred and seventy-two Aeromonas hydrophila strains were isolated from aquatic hosts including fish, turtle, frogs, shellfish and water itself . The aquatic organisms were compared with 45 clinical strains with regard to biotype, hemolysin, and antibiogram . The carrier rate of A . hydrophila in the aquatic environment was 61.7% . Of the aquatic strains 51% were hemolysin producers, equivalent to a capability for producing enterotoxin . The hemolysin-producing capability of aquatic strains was not significantly different from that of the clinical strains . The main code numbers or biotypes of aquatic strains were 3265 (29.4%), 3065 (17.5%), 7065 (9.6%), 7265, 3225 (each 8.5%) . The main code number or biotypes of clinical strains were 3265 (36.1%), 3065 (9.8%), 7261 (6.6%), 2265, 3261 and 6241 (each 4.9%) . Analysis of the antibiotic susceptibility pattern of both aquatic and clinical A . hydrophila strains using the microbroth dilution method showed that there is no significant difference in antibiotic susceptibility . Most aquatic and clinical strains were highly susceptible to tobramycin, gentamicin, amikacin, cefuroxime, piperacillin, cefotaxime and cefoperazone . Most strains of aquatic A . hydrophila were highly susceptible to cefamandole and chloramphenicol; however, clinical strains were only moderately susceptible to the same drugs . Most aquatic and clinical strains were highly resistant to ampicillin, and moderately resistant to sulbenicillin . Clinical strains were moderately resistant to cephapirin; however, aquatic strains were moderately susceptible to cephapirin . Based on the above findings, we may considered aquatic environment be, at least partially, the source of clinical strains . Furthermore, biotypes of aquatic A . hydrophila do not correspond to antibiogram or hemolysin-producing patterns. J Bacteriol, 1986 Apr, 166(1), 120 - 7 Two patterns in the Aeromonas salmonicida A-layer may reflect a structural transformation that alters permeability; Stewart M et al.; Electron micrographs of negatively stained regular surface layers (A-layers) of Aeromonas salmonicida showed two square patterns having p4 symmetry . Computer image processing demonstrated that, at a resolution of 2.3 nm, both square arrays were composed of two different morphological units arranged alternatively to give a face-centered lattice in which the four nearest neighbors of each unit were the other type of unit . The lattice constant was slightly but significantly different in the two patterns, and the orientation of one of the two morphological units changed by about 20 degrees between patterns . These patterns were probably not derived from different strains present in the preparation, since both were seen in material that appeared to come from a single layer . This and the difference in lattice constant made it unlikely that they represented different sides of the A-layer . However, it is possible that the two patterns may reflect a structural transformation of the layer . In this respect, it is interesting that the rotation of one morphological subunit changed the size of the gaps between units in the layer . This raised the possibility that the transformation could be related to a change in permeability of the A-layer, possibly analogous to that proposed for gap junctions in eucaryotic cells. Appl Environ Microbiol, 1986 Mar, 51(3), 668 - 70 Heme requirement for growth of fastidious atypical strains of Aeromonas salmonicida; Ishiguro EE et al.; The growth of fastidious atypical strains of the fish pathogen Aeromonas salmonicida on both solid and liquid media was dependent specifically on a source of heme which was apparently required for initiation of growth at low inoculum densities . Thus, hemin enhanced the plating efficiencies of such strains on solid medium and significantly reduced their inoculum-size-dependent lag times in broth . The heme requirement could also be satisfied by hematoporphyrin and, less effectively, by hemoglobin . Since the requirement was a stable property of all 17 strains tested, it may prove to be another taxonomic criterion by which the atypical strains can be differentiated from the typical strains of A . salmonicida. J Clin Microbiol, 1986 Mar, 23(3), 595 - 9 Prevalence, species differentiation, and toxigenicity of Aeromonas strains in cases of childhood gastroenteritis and in controls; Figura N et al.; In a 1-year period (January to December 1984), Aeromonas strains were isolated from feces of 21 of 561 (3.7%) children with gastroenteritis and from 12 of 576 (2.1%) children without intestinal disturbances (controls) . The difference between the two isolation rates was not significant (X2 = 2.2; P greater than 0.05) . In five cases of illness other intestinal pathogens were isolated together with Aeromonas in the same stool sample . A total of 39 Aeromonas strains were detected since in some cases aeromonads with different biochemical characteristics were obtained from the same stool sample . Of the 39 Aeromonas isolates, 6 strains (5 from patients) were Aeromonas hydrophila, 5 strains (3 from patients) were Aeromonas sobria, and 26 strains (18 from patients) were Aeromonas caviae; 2 strains isolated from controls did not ferment sucrose and were considered a distinct group of Aeromonas . We found no significant difference between the prevalence of each of these species from patients and the prevalence from controls . We found no significant difference in the prevalence of enterotoxin-producing strains (suckling mouse model), cytotoxin-producing strains (HEp-2 cell model), or hemolysin-producing strains (rabbit erythrocyte model) between patients and controls . In our geographical region there is no evidence that Aeromonas species are primary intestinal pathogens in children. Am J Clin Pathol, 1986 Mar, 85(3), 330 - 6 The clinical significance of stool isolates of aeromonas; Travis LB et al.; The purpose of this study was to determine the clinical significance of different Aeromonas species isolated from stool . During a 17-month period, 29 strains of Aeromonas were isolated and identified to species with the following results: 22, A . caviae, 5, A . hydrophila, and 2, A . sobria . Clinical significance was determined independently of knowledge of speciation result . Nineteen isolates represented colonization, implying that Aeromonas can be recovered from the gastrointestinal tract without causing primary disease . The remaining 10 isolates were of indeterminate significance and may have played a role in infection, but pertinent tests to rule out other enteric pathogens had not been done . A correlation between species and clinical significance could not be established . Antimicrobial susceptibility testing was performed on the 29 isolates . A . caviae showed an unexpected resistance to cefazolin and cefoxitin, whereas representatives of all three species displayed resistance to trimethoprim/sulfamethoxazole. Can J Microbiol, 1986 Jan, 32(1), 1 - 3 The interaction of complement components with Aeromonas species; Brenden RA et al.; The interaction of seven serum-sensitive Aeromonas strains with the complement system was investigated using a 2-h quantitative assay . Of the strains tested, four isolates activated both the alternative and classical pathways, two activated only the alternative pathway, and one strain was sensitive to the bactericidal action of complement through the classical pathway only . Two of the four Aeromonas caviae strains were such efficient activators of the complement system that when challenged with human sera deficient in normal concentrations of C3 and C4, they were still subject to complement-mediated bacterial lysis . This phenomenon, in conjunction with previous studies on complement activation by Aeromonas spp., may help account for the decreased incidence observed of systemic disease caused by Aeromonas caviae. Rev Argent Microbiol, 1986, 18(3-4), 121 - 6 {Aeromonas hydrophila in waters of Lake San Roque and its tributaries}; Fracchia de Salvay Y; The presence of Aeromonas hydrophila in 72 samples of water of Lake San Roque and two rivers that flow into it, situated in Punilla Valley, Cordoba was investigated . Water-peptone Alkaline (enrichment medium) and Rippey Cabelli Agar without ampicillin (selective and differential medium for Aeromonas hydrophila) were used for isolation . The colonies obtained were assayed by oxidase test and subsequent oxidation-fermentation of Hugh Leifson, motility, urease, mannitol and trehalose fermentation, ornithine and lysine decarboxylation . Voges Proskauer and gas production from glucose and glycerol . Aeromonas hydrophila was isolated in 13% of water samples obtained in days with high temperature . Although this finding is not alarming, its presence should be taken into account because of its potential pathogenesis. Circ Shock, 1986, 20(4), 291 - 7 Prostacyclin and thromboxane A2 in septic shock: species differences; Yellin SA et al.; Prostacyclin and thromboxane A2 have been implicated as mediators of septic shock . Correlations between the human prostanoid response to sepsis and experimental paradigms are poorly understood . The purpose of this study was to compare changes in plasma levels of prostaglandin 6-keto-F1 alpha (PGI) and thromboxane B2 (TxB) during septic shock in Sprague-Dawley rats, domestic pigs, mongrel dogs, and man . Severe sepsis followed by septic shock (systolic BP less than 90 mmHg) was induced in rats by inoculation of 1.0 X 10(9) Aeromonas hydrophila, in pigs by graded IV infusion of 1.0 X 10(9)/ml A . hydrophila; and in dogs by an IV bolus injection of 5.0 X 10(9)/ml Escherichia coli . Plasma PGI and TxB (pg/ml) were measured by radioimmunoassay in control, septic, and septic shock experimental blood samples, and in normal controls, severly septic, and septic shock (systolic BP less than 90 mmHg) S.I.C.U . patients . Control, septic, and septic shock TxB levels in the dog and the pig were significantly greater than in the rat and man . PGI levels in the dog were significantly greater than in other species . TxB increased significantly in murine sepsis and PGI increased significantly in sepsis and septic shock . TxB increased during porcine sepsis and septic shock . In man, both PGI and TxB were significantly increased in severe sepsis, compared to normal controls, but only PGI was significantly higher in septic shock versus normotensive sepsis . Patterns of change in TxB/PGI ratios were similar for all species studied . Changes in PGI in the porcine septic experiments most closely paralleled those observed clinically. Vet Hum Toxicol, 1986, 28 Suppl 1, 45 - 54 Stress factors that can affect studies of drug metabolism in fish; Sommer CV et al.; The effects of environmental stress conditions on the defense response of rainbow trout following a four week exposure to subacute levels of un-ionized ammonia or temperatures 5 C above and 5 C below the temperature optimum (15 C) were investigated . These experimental studies can serve as a model to evaluate the metabolic response of fish to external agents (e.g., drugs, vaccines) under environmental conditions seen in the culture of fish . Blood and tissue immune parameters measured include hematocrits, antibody levels and differentiation of white blood cell populations in tissue imprints of the anterior kidney . These analyses were compared to the growth parameter, average percent weight gain . Fish given primary and secondary immunization with a bacterial vaccine (Aeromonas hydrophila) were exposed to sublethal concentrations of un-ionized ammonia of 0.2, 0.3 or 0.4 mg/ml . Fish exposed to the higher concentrations of ammonia showed a decrease in growth compared to control fish . Several significant changes were observed in the leukocytes of the anterior kidney at the various concentrations of ammonia tested . A decrease in antibody titers to A hydrophila was seen at the two higher concentrations of ammonia . In a second study, the effects of non-optimum temperature conditions (10 C and 20 C) were compared with an optimum temperature (15 C) . Fish held at sub-optimum temperatures had significantly lower hematocrits than the control fish maintained at 15 C . Several significant changes were also seen in the anterior kidney leukocytes . Antibody titers to A hydrophila were significantly lower at the end of the stressing period in the trout maintained at 10 C compared to the immunized controls at 15 C . In contrast, fish held at 20 C had significantly higher antibody titers than did the immunized controls . Compared to controls, fish growth was increased at 10 C and decreased at 20 C . These studies confirm that environmental factors can induce stress and affect the metabolism and health of the fish. J Antimicrob Chemother, 1986 Jan, 17(1), 45 - 50 Beta-lactamases with high activity against imipenem and Sch 34343 from Aeromonas hydrophila; Shannon K et al.; Two groups of inducible beta-lactamases were found among nine isolates of Aeromonas hydrophila . Five isolates produced enzymes with high activity against the penem Sch 34343 and the carbapenem imipenem: the enzymes from some of these isolates also had activity against penicillin, ampicillin, carbenicillin, cephaloridine and cephalexin but one isolate produced an enzyme with no detectable activity against cephalosporins . The other four isolates produced typical 'cephalosporinases' with activity against cephaloridine and cephalexin but not against cefuroxime, cefotaxime, penicillins, imipenem or Sch 34343. Vet Hum Toxicol, 1986, 28 Suppl 1, 11 - 7 Antimicrobials and fish: a review of drugs used to treat bacterial diseases of channel catfish and rainbow trout; Herman RL et al.; The principal bacterial diseases of cultured rainbow trout (Salmo gairdneri) and channel catfish (Ictalurus punctatus), and the antibacterials used in their treatment are briefly reviewed . Gram-negative bacteria predominate, and oxytetracycline is effective in treatment of infections induced by them . The only antibacterials now registered by the US Food and Drug Administration are sulfamerazine for the treatment of furunculosis in trout, and oxytetracycline for the treatment of furunculosis in salmonids and Aeromonas and Pseudomonas infections in salmonids and catfish . Registration 9/50 is now complete for the potentiated sulfonamide Romet-30 for controlling furunculosis in salmonids . Studies on the metabolism of antibacterials in fishes are limited, and are primarily concerned with tissue residue and elimination rate. Bull Soc Pathol Exot Filiales, 1986, 79(4), 447 - 57 {Diarrhea caused by Aeromonas in Ivory Coast}; Dosso M et al.; The authors drawn epidemiological, clinical conclusions, and the geographical data concerning the diarrheas with Aeromonas in Ivory-Coast . The results relate to a study realized from January 1982 to July 1985 . Out of the 1,594 excrements 627 germes have been isolated and among which 153 strains of aeromonas if for instance 24.4% of the whole germs . Aeromonas caviae is the most frequent species (50%) compared to 27.3% for Aeromonas sobria, and 22.7% for Aeromonas hydrophila. Arch Intern Med, 1985 Dec, 145(12), 2207 - 11 Aeromonas-related diarrhea in adults; George WL et al.; We have reviewed the incidence of Aeromonas in patients with enteric disease at our hospital and found it to be the highest of any potential enteric pathogen . Eighty adult patients with diarrhea had Aeromonas isolated from feces, and in 73 Aeromonas was the only potential bacterial or parasitic pathogen detected . The spectrum of illness in patients with Aeromonas-related diarrhea ranged from acute, self-limited diarrhea to a chronic, indolent diarrheal illness . Sixteen percent (13/80) of the patients had evidence of colitis noted during sigmoidoscopy or colonoscopy . Our data (and those from other studies) indicate that Aeromonas is relatively common in the feces of adults with diarrhea; they also indicate the need for prospective, controlled clinical and bacteriological studies to determine whether or not Aeromonas is an important enteric pathogen in adults. J Clin Microbiol, 1985 Dec, 22(6), 1061 - 2 Identification of hydroxy fatty acids in Aeromonas hydrophila, Aeromonas sobria, and Aeromonas caviae; Canonica FP et al.; Gas-liquid chromatographic analysis of fatty acid methyl esters obtained from clinical isolates of Aeromonas hydrophila, A . sobria, and A . caviae revealed the presence of two hydroxy fatty acid species, 3-OH 12:0 and 3-OH 14:0. J Bacteriol, 1985 Dec, 164(3), 1233 - 7 Congo red agar, a differential medium for Aeromonas salmonicida, detects the presence of the cell surface protein array involved in virulence; Ishiguro EE et al.; Strains of the fish pathogen Aeromonas salmonicida which possess the cell surface protein array known as the A-layer (A+) involved in virulence formed deep red colonies on tryptic soy agar containing 30 micrograms of Congo red per ml . These were readily distinguished from colorless or light orange colonies of avirulent mutants lacking A-layer (A-) . The utility of Congo red agar for quantifying A+ and A- cells in the routine assessment of culture virulence was demonstrated . Intact A+ cells adsorbed Congo red, whereas A- mutants did not bind Congo red unless first permeabilized with EDTA . The dye-binding component of A+ cells was shown to be the 50,000-Mr A-protein component of the surface array . Purified A-protein avidly bound Congo red at a dye-to-protein molar ratio of about 30 by a nonspecific hydrophobic mechanism enhanced by high salt concentrations . Neither A+ nor A- cells adsorbed to Congo red-Sepharose columns at low salt concentrations . On the other hand, A+ (but not A-) cells were avidly bound at high salt concentrations. J Bacteriol, 1985 Dec, 164(3), 1332 - 6 Porphyrin binding by the surface array virulence protein of Aeromonas salmonicida; Kay WW et al.; Congo red binding by virulent A-layer-containing (A+) and avirulent A-layer-deficient (A-) strains of Aeromonas salmonicida was examined . Congo red binding to A+ cells was enhanced by salt and thus hydrophobically driven, but at low Congo red concentrations binding was salt independent . Congo red was bound by A+ cells by a kinetically distinct mechanism (Kd, 0.25 microM) which was absent in A- isogenic strains . Purified A-layer protein ("A protein") protein A also bound Congo red with similar affinity (Kd, 0.40 microM) . Congo red binding was structurally specific; it was not influenced by a wide variety of compounds including amino acids and nucleotides and only weakly inhibited by structurally similar dyes . However, protoporphyrin IX and hemin were strong competitive inhibitors of Congo red binding . Protoporphyrin and hemin were bound only by A+ strains (KdS of 0.41 and 0.63 microM, respectively) . Furthermore, binding of these porphyrins was strongly inhibited by Congo red but weakly inhibited by hematoporphyrin . Purified A protein also bound protoporphyrin IX and hemin with affinities similar to those of A+ cells (KdS of 0.94 and 0.41 microM, respectively. Southeast Asian J Trop Med Public Health, 1985 Dec, 16(4), 532 - 3 Purpura fulminans produced by Aeromonas hydrophila: a case report; Thisyakorn U et al.; A case of purpura fulminans produced by Aeromonas hydrophila in a twelve year-old Thai boy was reported . The patient also had aplastic anemia which facilitated the severity of disease . He died despite appropriate antimicrobial therapy. J Gen Microbiol, 1985 Dec, 131 ( Pt 12), 3385 - 91 Comparative electrophoretic profiles of esterases, and of glutamate, lactate and malate dehydrogenases, from Aeromonas hydrophila, A . caviae and A . sobria; Picard B et al.; Esterases, and glutamate, lactate and malate dehydrogenases of 64 Aeromonas hydrophila, A . caviae and A . sobria strains, were analysed by polyacrylamide agarose gel electrophoresis and by thin layer isoelectrofocusing . On the basis of the isoelectric points of malate dehydrogenase from the three species and the mobility of lactate dehydrogenase from A . sobria, 8 species specific zymotypes were defined: three for A . hydrophila strains, three for A . caviae strains and two for A . sobria strains . These zymotypes correlated with previously established DNA hybridization groups . The other electrophoretic data were found to be less useful for distinction between A . hydrophila and A . sobria strains, but supported differentiation into zymotypes for A . caviae strains . The two-dimensional electrophoretic profile established by plotting isoelectric point against electrophoretic mobility of the major esterase illustrated the degree of enzyme polymorphism among the strains of the three species . Variation in electrophoretic patterns within A . hydrophila and A . caviae might provide useful epidemiological markers. J Clin Microbiol, 1985 Nov, 22(5), 888 - 90 Media for the isolation of Aeromonas hydrophila; Kay BA et al.; Isolation rates of Aeromonas hydrophila from stool samples of symptomatic and asymptomatic individuals were examined for several common enteric media . Sheep blood agar with 10 micrograms of ampicillin per ml, preceded by overnight enrichment in alkaline peptone water, yielded 2.6 times the number of isolates as the other media examined and is recommended for the isolation of A . hydrophila from humans. J Clin Microbiol, 1985 Nov, 22(5), 854 - 5 Cephalothin susceptibility as a potential marker for the Aeromonas sobria group; Janda JM et al.; Fifty-four motile Aeromonas strains, composing the three currently recognizable species, were tested for susceptibility to cephalothin by broth dilution and disk agar diffusion assays . Cephalothin susceptibility was significantly associated with Aeromonas sobria (P less than 0.001) and may be an additional phenotypic marker useful in the identification of this species. J Biol Chem, 1985 Oct 25, 260(24), 13154 - 62 The slow, tight binding of bestatin and amastatin to aminopeptidases; Wilkes SH et al.; Bestatin reversibly inhibits Aeromonas aminopeptidase (EC 3.4.11.10) in a process that is remarkable for its unusual degree of time dependence . The binding of bestatin by both Aeromonas aminopeptidase and cytosolic leucine aminopeptidase (EC 3.4.11.1) is slow and tight, with Ki values (determined from rate constants) of 1.8 X 10(-8) and 5.8 X 10(-10) M, respectively . In contrast, microsomal aminopeptidase (EC 3.4.11.2) binds bestatin in a rapidly reversible process with a Ki value of 1.4 X 10(-6) M . Kinetic analysis of the slow inhibition observed is facilitated by the use of a variety of experimental treatments, primarily measurements made during pre-equilibrium; however, careful selection of conditions permits use also of steady state observations . When titrated with bestatin, 1 mol of cytosolic leucine aminopeptidase (containing 6 g atoms each of zinc and manganese) is rendered 80% inactive by 1 mol of inhibitor, thus suggesting that enzymatic activity depends on one active site/hexamer; titration of Aeromonas aminopeptidase by bestatin reveals a 1:1 stoichiometry . Amastatin inhibits all three aminopeptidases through the mechanism of slow, tight binding with Ki values ranging from 3.0 X 10(-8) to 2.5 X 10(-10) M . This behavior of microsomal aminopeptidase contrasts sharply with its rapidly reversible inhibition by bestatin . The slow, tight binding observed with five of the six aminopeptidase-inhibitor pairs investigated suggests the formation of a transition state analog complex between the enzyme and inhibitor . Physical evidence consistent with this possibility was provided by the observation that both bestatin and amastatin perturb the absorption spectrum of cobalt Aeromonas aminopeptidase. Infect Immun, 1985 Oct, 50(1), 62 - 5 Lack of correlation between known virulence properties of Aeromonas hydrophila and enteropathogenicity for humans; Morgan DR et al.; Five strains of Aeromonas hydrophila were selected for use in volunteer challenge trials . All five strains produced cytotoxin, hemolysin enterotoxin, lysine decarboxylase, acetylmethylcarbinol, and DNase . Two strains hydrolyzed esculin . All strains produced purulent hemorrhagic fluid accumulation in rabbit ileal loops, but failed to induce keratoconjunctivitis in guinea pigs . None of the strains produced mannose-resistant hemagglutinins . In challenge studies, diarrhea was demonstrated in only 2 of 57 human volunteers with doses ranging from 10(4) to 10(10) CFU . One person experienced mild diarrhea with 10(9) CFU of strain 6Y . A second person developed moderate diarrhea with 10(7) CFU of strain 3647 . At higher doses, no diarrhea was seen in any of the volunteers . The other three strains (B158, SSU, 3284) failed to cause diarrhea and were not recovered from stools of volunteers . Additional virulence properties of A . hydrophila need to be sought before enteropathogenicity for humans can be established. Infect Immun, 1985 Oct, 50(1), 322 - 3 Demonstration of cholera toxin-related factor in cultures of Aeromonas species by enzyme-linked immunosorbent assay; Honda T et al.; The production of toxins by Aeromonas species was examined by the suckling mouse test, the hemolysin test, and the enzyme-linked immunosorbent assay with anticholera enterotoxin . A factor that was immunologically related to cholera enterotoxin was produced by 5 of 14 strains of Aeromonas hydrophila and 4 of 15 strains of Aeromonas sobria . Analysis by these assays and by a test for heat stability suggested that the factor differed from hemolysin and from toxin that was active in the suckling mouse test. J Gen Microbiol, 1985 Oct, 131 ( Pt 10), 2825 - 30 Molecular cloning and expression of a xylanase gene of alkalophilic Aeromonas sp . no . 212 in Escherichia coli; Kudo T et al.; A gene coding for a xylanase activity of alkalophilic Aeromonas sp . no . 212 (ATCC 31085) was cloned in Escherichia coli HB101 with pBR322 . Plasmid pAX1 was isolated from transformants producing xylanase, and the xylanase gene was located in a 6.0 kb Hind III fragment . The pAX1-encoded xylanase activity in E . coli HB101 was about 80 times higher than that of xylanase L in alkalophilic Aeromonas sp . no . 212 . About 40% of the enzyme activity was observed in the periplasmic space of E . coli HB101 . The pAX1-encoded xylanase had the same enzymic properties as those of xylanase L produced by alkalophilic Aeromonas sp . no . 212, but its molecular weight was lower (135 000 vs 145 000, as estimated by SDS polyacrylamide gel electrophoresis). J Bacteriol, 1985 Oct, 164(1), 263 - 9 Electrophoretic and immunochemical analyses of the lipopolysaccharides from various strains of Aeromonas hydrophila; Dooley JS et al.; Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was used to analyze the lipopolysaccharides isolated from strains of Aeromonas hydrophila which exhibit virulence for fish and which autoaggregate during growth in static broth culture . The lipopolysaccharides contained O-polysaccharide chains of homogeneous chain length . Two of the strains produced a surface protein array, and immunofluorescence and phage-binding studies revealed that a number of these O-polysaccharide chains of homogeneous length traversed the protein array and were exposed on the cell surface . Immunochemical analyses by immunoblotting, enzyme-linked immunosorbent assay, immunofluorescence, and immunoprecipitation with both polyclonal and monoclonal antibodies revealed the presence of three epitopes on the polysaccharide moiety of this homogenous-chain-length lipopolysaccharide morphotype . One epitope was species serogroup specific and reactive by immunoblotting . This epitope was not present on the heterogeneous-chain-length O polysaccharides of nonautoaggregating strains of A . hydrophila examined . The second epitope was conformation dependent and cross-reactive with an epitope on the homogenous-chain-length O polysaccharides of Aeromonas salmonicida lipopolysaccharide . The third epitope was recognized by a monoclonal antibody and appeared to involve that region of the A . hydrophila and A . salmonicida lipopolysaccharide molecules which contained the O-polysaccharide-core oligosaccharide glycosidic linkage. Biochemistry, 1985 Sep 24, 24(20), 5350 - 6 Spectral and kinetic studies of metal-substituted Aeromonas aminopeptidase: nonidentical, interacting metal-binding sites; Prescott JM et al.; Apoenzyme prepared by removal of the 2 mol of Zn2+/mol from Aeromonas aminopeptidase is inactive . Addition of Zn2+ reactivates it completely, and reconstitution with Co2+, Ni2+, or Cu2+ results in a 5.0-, 9.8-, and 10-fold more active enzyme than native aminopeptidase, respectively . Equilibrium dialysis and spectral titration experiments with Co2+ confirm the stoichiometry of 2 mol of metal/mol . The addition of only 1 mol of metal/mol completely restores activity characteristic of the particular metal . Interaction between the two sites, however, causes hyperactivation; thus, addition of 1 mol of Zn2+/mol subsequent to 1 mol of Co2+, Ni2+, or Cu2+ per mole increases activity 3.2-, 42-, or 59-fold, respectively . The cobalt absorption spectrum has a peak of 527 nm with a molar absorptivity of 53 M-1 cm-1 for 1 mol of cobalt/mol, which increases to 82 M-1 cm-1 for a second cobalt atom and is unchanged by further addition of Co2+ . Circular dichroic (CD) and magnetic CD spectra indicate that the first Co2+ binding site is tetrahedral-like and that the second is octahedral-like . Stoichiometric quantities of 1-butylboronic acid, a transition-state analogue inhibitor of the enzyme {Baker, J . O., & Prescott, J . M . (1983) Biochemistry 22, 5322}, profoundly affects absorption, CD, and MCD spectra, but n-valeramide, a substrate analogue inhibitor, has no effect . These findings suggest that the tetrahedral-like site is catalytic and the other octahedral-like site is regulatory or structural. Infection, 1985 Sep-Oct, 13(5), 228 - 30 Aeromonas caviae: an enteric pathogen? Altwegg M. Of the Aeromonas spp . isolated routinely in our laboratory from human feces, about two thirds represent Aeromonas caviae . In contrast to Aeromonas hydrophila and Aeromonas sobria, this species has been considered to be of little enteropathogenic significance due to the absence of known virulence factors . The clinical data presented here suggest a clinical significance of A . caviae, at least in some cases . As yet nothing is known about the pathogenic mechanisms involved. Infect Immun, 1985 Sep, 49(3), 756 - 9 Role of caseinase from Aeromonas salmonicida in activation of hemolysin; Titball RW et al.; Mutants of the bacterial fish pathogen Aeromonas salmonicida selected for inability to digest casein concomitantly lost hemolytic activity against horse erythrocytes under certain conditions . Mixtures of wild-type with mutant culture supernatants indicated that mutants produce an inactive precursor of a hemolysin which was activated by autogenous caseinase and, with less efficiency, by other serine proteases . Selective inhibition or repression of caseinase production in the wild-type strain also resulted in the production of an inactive precursor of a hemolysin . The precursor of hemolysin was also activated by a serum factor which appeared to exert its maximum effect at the bacterial surface or after entry into the bacterial cell . These results could affect the interpretation of studies evaluating the role of individual extracellular products in the pathogenesis of A . salmonicida infections. J Bacteriol, 1985 Sep, 163(3), 877 - 81 Synthesis, export, and assembly of Aeromonas salmonicida A-layer analyzed by transposon mutagenesis; Belland RJ et al.; Suicide plasmid pJB4JI, containing transposon Tn5 and phage Mu, was introduced into Aeromonas salmonicida 449 which produces a surface protein array known as the A-layer . Kanamycin-resistant exconjugants of 449 with altered ability to produce the A-layer were selected by virtue of their altered colonial morphology and color on medium containing the dye Congo red . Analysis of culture supernatants, periplasmic shock fluid, outer membranes, and whole-cell lysates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with a monoclonal antibody to A-protein revealed five classes of single-insertion mutations that affected the ability of cells to produce and export A-protein and to assemble the A-layer . These studies suggest that A-protein is produced from a single chromosomal gene . The subunits subsequently pass through the periplasm and across the outer membrane . At least one gene product is required for this export . Assembly of A-layer on the cell surface then requires the presence of O polysaccharide chains on the lipopolysaccharide . In one case, insertion of Tn5 resulted in loss of ability to produce both A-protein and lipopolysaccharide with O polysaccharide chains, suggesting that synthesis of A-protein and synthesis of lipopolysaccharide may involve coordinate regulation. Biochem Biophys Res Commun, 1985 Aug 15, 130(3), 1154 - 60 A transition-state-analog inhibitor influences zinc-binding by Aeromonas aminopeptidase; Baker JO et al.; The transition-state-analog inhibitor, 1-butaneboronic acid, markedly enhances the uptake of one g-atom of Zn2+ ions from a metal ion buffer system by Zn-depleted Aeromonas aminopeptidase . In contrast, a substrate-analog inhibitor, n-valeramide, does not perturb the equilibrium between Zn2+ ions and the enzyme in a metal ion buffer system . These results establish a role for metal ions in the binding of 1-butaneboronic acid to Aeromonas amino-peptidase and strongly imply that a bound Zn2+ ion interacts directly with substrate during catalysis but not during initial binding of substrate. Avian Dis, 1985 Jul-Sep, 29(3), 681 - 9 Prevalence and pathogenicity of Aeromonas hydrophila; Shane SM et al.; A field survey to determine the prevalence of Aeromonas hydrophila revealed a recovery rate of 8% in 141 specimens derived from a range of live, companion, and exotic avian species . The prevalence rate was similar in 240 sequential postmortem submissions during 1984 . Studies on the pathogenicity of A . hydrophila showed that 2-to-4-day-old chicks and turkey poults were highly susceptible to exposure via the subcutaneous, yolk-sac, and intracerebral routes, and mortality of 80-100% occurred within 48 hours of inoculation . Ducklings aged 4 days were generally refractory to exposure. J Gen Microbiol, 1985 Jul, 131 ( Pt 7), 1603 - 9 The purification and some properties of H-lysin from Aeromonas salmonicida; Titball RW et al.; H-lysin from Aeromonas salmonicida has been purified 1770-fold by freeze fractionation, ammonium sulphate precipitation, ion exchange chromatography and gel filtration chromatography . The purified material was predominantly H-lysin, devoid of detectable T-lysin, caseinase or gelatinase activity, although glycerophospholipid: cholesterol acyltransferase (GCAT) activity was present . The results suggested that H-lysin and GCAT activities were due to different extracellular products . Studies of the kinetics of haemolysis indicated that the H-lysin had an enzymic mode of action, and that initial erythrocyte damage appeared to precede lysis of the cell . The H-lysin was lethal to cultured rainbow trout gonad cells and leucocytes, but when it was injected intravenously in rainbow trout no pathological effects were observed. Antimicrob Agents Chemother, 1985 Jul, 28(1), 151 - 3 In vitro susceptibilities of Aeromonas hydrophila, Aeromonas sobria, and Aeromonas caviae to 22 antimicrobial agents; Motyl MR et al.; MICs of 22 antimicrobial agents for 60 strains of three Aeromonas species were determined by a microdilution method . The newer cephalosporins such as moxalactam, cefotaxime, and cefoperazone, the aminoglycosides, and chloramphenicol, tetracycline, nitrofurantoin, and trimethoprim-sulfamethoxazole inhibited most of the strains studied . Within the genus, A . hydrophila was more resistant than either A . caviae or A . sobria to the antibiotics tested. J Bacteriol, 1985 Jul, 163(1), 336 - 40 Activation of the hole-forming toxin aerolysin by extracellular processing; Howard SP et al.; A precursor-product relationship between aerolysin and a protein with a higher molecular weight was observed in culture supernatants of Aeromonas hydrophila . The larger protein was isolated by ammonium sulfate precipitation and ion-exchange and hydroxyapatite chromatography and compared with purified aerolysin . It was at least 250 times less hemolytic than aerolysin . Both proteins had the same amino acid sequence at the amino terminus . Cyanogen bromide fragments obtained from the two were identical except that each protein contained one unique fragment, and the fragment from the larger protein was 2,500 daltons larger than the fragment obtained from aerolysin . Treatment with trypsin or with an extracellular Aeromonas protease resulted in rapid conversion of the larger protein to a form corresponding in molecular weight and activity to aerolysin . The results indicate that aerolysin is exported to the culture supernatant as a protoxin which is later activated by proteolytic removal of a peptide from the C terminus. Jpn J Med Sci Biol, 1985 Jun, 38(3), 141 - 5 Peritrichous flagella in mesophilic strains of Aeromonas; Shimada T et al.; A total of 186 mesophilic strains of Aeromonas, comprising 151 A . hydrophila and 35 A . caviae, were tested for peritrichous flagella by Leifson's staining method . When incubated on solid medium for 18 hr at 22 C, peritrichous flagella were demonstrated in 28 (18.5%) of the 151 strains of A . hydrophila and in 6 (17.1%) of the 35 strains of A . caviae . The peritrichous flagella in these 34 mesophilic strains of Aeromonas were also observed by electron microscopy. J Clin Microbiol, 1985 Jun, 21(6), 909 - 13 Clinical and microbiological features of Aeromonas hydrophila-associated diarrhea; Agger WA et al.; The prevalence of Aeromonas hydrophila in stool specimens from patients with diarrhea was studied during 18 months . A . hydrophila was found in 1.1% of patients with diarrhea and in none of 533 control patients (P less than 0.02) . Cases were detected 1.5 times more often during the summer months than the winter months, and most occurred in children less than 2 years of age . Clinical features included fever greater than 38 degrees C (55%), abdominal cramps (35%), vomiting (25%), and duration of illness greater than 10 days (50%) . Detection of A . hydrophila in stools was facilitated by the use of sheep blood agar with 15 micrograms of ampicillin per ml which was flooded with oxidase reagent after growth . A cytotoxin was produced by 62% of the isolates, and the cytotoxic strains showed positive results in a hemolysin assay and a lysine decarboxylase reaction. Rev Infect Dis, 1985 May-Jun, 7(3), 314 - 20 Bacteremia caused by Aeromonas species in hospitalized cancer patients; Harris RL et al.; Bacteremia caused by Aeromonas species occurred in 24 hospitalized patients in a cancer institute during a 13-year period . All but one of these patients had a malignancy (88% had leukemia), and most were receiving chemotherapy for cancer . There was a striking numerical predominance of male patients (82%) . Unlike some previously described patients with infections due to this organism, none of these 24 patients had recently been exposed to fresh or salt water or to fish . The source of the infecting organism was thought to be endogenous--i.e., from patients' own gastrointestinal tracts . The clinical presentation of sepsis caused by this organism was nonspecific, except that ecthyma gangrenosum occurred in several patients . The overall mortality rate was 28% . The combination of an aminoglycoside and a cephalosporin is appropriate therapy for bacteremia caused by Aeromonas species. J Med Microbiol, 1985 Apr, 19(2), 273 - 7 Methods for the detection of haemagglutinins in Aeromonas; Crichton PB et al.; When grown in specified conditions and tested by a rocked-tile method, 40 of 41 isolates of two species of Aeromonas formed simultaneously at least two haemagglutinins among which were: (i) a mannose-sensitive haemagglutinins with strongest activity for guinea-pig or fowl red cells, formed by all of 31 isolates of A . hydrophila and 9 of 10 isolates of A . punctata ss . caviae; (ii) a haemagglutinin, sensitive to L-fucose or D-mannose, that reacted with human red cells and which was formed by all 41 isolates; and (iii) a mannose-resistant 'tanned red cell' haemagglutinin formed by 29 isolates of A . hydrophila and one isolate of A . punctata ss . caviae . Results emphasise that for the fullest possible identification of haemagglutinins produced by Aeromonas spp., strains should be cultured in a variety of conditions and tested with a wide range of red-cell species. Antimicrob Agents Chemother, 1985 Apr, 27(4), 479 - 84 Genetic and biochemical properties of AER-1, a novel carbenicillin-hydrolyzing beta-lactamase from Aeromonas hydrophila; Hedges RW et al.; A novel carbenicillin-hydrolyzing beta-lactamase has been discovered in a blood isolate of Aeromonas hydrophila . The enzyme resembles plasmid-determined carbenicillinases in substrate profile but differs in isoelectric point (pI 5.9) and molecular weight (22,000) and has been termed AER-1 . No evidence for a plasmid location could be obtained in A . hydrophila, but the AER-1 gene and resistance to chloramphenicol, streptomycin, and sulfonamide could be transferred by mobilization with IncP plasmids to Escherichia coli, where the gene cluster inserted at a unique chromosomal site . The linked resistances are similar to those found on multiresistance beta-lactamase transposons, but since insertion of the A . hydrophila gene cluster was site specific and recA+ dependent, the cluster is not a functional transposon. Infect Immun, 1985 Apr, 48(1), 146 - 52 Loss of virulence in a protease-deficient mutant of Aeromonas salmonicida; Sakai DK; The importance of extracellular protease production by Aeromonas salmonicida, the bacterial pathogen of fish furunculosis, was investigated with four virulent strains (which were autoagglutinative, hemagglutinative, resistant to fish serum, adhesive to fish tissue culture, protease positive, hemolysin positive, and leukocytolysin positive) and three avirulent strains (which were nonagglutinative, nonhemagglutinative, sensitive to serum, nonadhesive, protease positive, hemolysin positive, and leukocytolysin positive) . A protease-deficient mutant (NTG-1) was induced by mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine from virulent strain A-7301, showing protease production, which was common to the two strain groups . Strain NTG-1 showed loss of virulence in determinations of 50% lethal doses, although it remained autoagglutinative, hemagglutinative, serum resistant, adhesive, hemolysin positive, and leukocytolysin positive . A protease fraction separated from extracellular products of strain A-7301 by DEAE-cellulose column chromatography had the capacity to produce skin lesions (furuncles) and high mortality in sockeye salmon . A comparable protein fraction from extracellular products of NTG-1 resulted in no protease activity and no pathological effects on the fish . The avirulent strains were eliminated from rainbow trout in a short time, whereas the virulent strains (including A-7301) were highly infective and proliferated in hosts . NTG-1 preserved its infectivity, but fish showed no signs of disease and no mortality . These findings indicate that extracellular protease is a major virulence factor and that protease production in the host is closely implicated in the pathogenesis of fish furunculosis. J Bacteriol, 1985 Mar, 161(3), 1118 - 24 Protein export by a gram-negative bacterium: production of aerolysin by Aeromonas hydrophila; Howard SP et al.; The synthesis and export of aerolysin, an extracellular protein toxin released by the gram-negative bacterium Aeromonas hydrophila, was studied by pulse-labeling with {35S}methionine . The toxin was synthesized as a higher-molecular-weight precursor . This was processed cotranslationally, resulting in the appearance within the cell of the mature protein, which was then exported to the supernatant . Precursor aerolysin accumulated in cells incubated in the presence of carbonyl cyanide m-chlorophenyl hydrazone, a substance which also inhibited the export of mature aerolysin from the cell . The entrapped mature toxin could not be shocked from the cells, although it could be digested by protease applied to shocked cells . The toxin was processed and translocated across the inner membrane of pleiotropic export mutants and accumulated in the periplasm . The results indicate that more than one step is required for the export of the protein and that aerolysin does not cross the inner and outer membranes simultaneously. J Hosp Infect, 1985 Mar, 6(1), 75 - 80 Aeromonas hydrophila in chlorinated water supplies; Millership SE et al.; Methods for the isolation and enumeration of Aeromonas hydrophila in water supplies are described . Examination of 286 chlorinated samples collected between July and October showed that 19% of otherwise uncontaminated waters contained Aerom . hydrophila, rising to 71% of those from which Escherichia coli was isolated . The isolation rate during January and February was only 7% for all samples . On the basis of these results, tap water is a likely source of the aeromonads found in human intestinal flora. Ann Biol Clin (Paris), 1985, 43(5), 725 - 31 {Isolation of Aeromonas hydrophila in diarrhea . Characterization of enterotoxinogenic strains and clinical relations}; Brauer C et al.; Aeromonas hydrophila is isolated from diarrhoea specimens with increasing frequency . The interest in this organism at the present time is related to the fact that it can produce a number of toxins, in particular alpha and beta cytotoxic haemolysins, an enterotoxin and various enzymes . The authors determined the frequency of isolation of this organism and tested the haemolytic, cytotoxic and enterotoxic effects of culture filtrates in all of the stool specimens received in their laboratory over a period of 9 months . At the same time, the clinical context was defined in order to demonstrate a relation between the aptitude of the strains to produce toxins and the presence of diarrhoea . The frequency of isolation of A . hydrophila was 0.88 per cent, which corresponds to 67 strains . 38 strains presented a haemolytic and/or enterotoxic activity, i.e . 57 per cent of the strains isolated . In diarrhoeal stools, 67 per cent of the A . hydrophila isolated produced at least one of the toxins, while in the group of patients without diarrhoea, only 38 per cent of the strains isolated produced toxins . The results obtained reveal a statistically significant correlation between the production of cytotoxic haemolysin and the presence of diarrhoea . In contrast, there was no correlation between the production of enterotoxin and the presence of diarrhoea . Twenty of the 67 strains ware isolated from children under the age of 2 years . In 40 per cent of cases, no other aetiology could be found for the diarrhoea, apart from the isolation of A . hydrophila.(ABSTRACT TRUNCATED AT 250 WORDS) Cell Tissue Res, 1985, 242(3), 491 - 8 Antigen localization in the lymphoid organs of carp (Cyprinus carpio); Lamers CH et al.; A brief morphological description is given of the spleen, head kidney and trunk kidney, the three peripheral lymphoid organs of carp . An antigen-localization study was carried out using Aeromonas hydrophila (a cellular bacterial antigen) and an indirect immunofluorescence test . Examination of the lymphoid organs at various times after injection (up to 12 months) showed that antigen was at first present in splenic ellipsoids and in solitary phagocytic cells in the spleen, head and trunk kidney . Later on, the antigen was gradually concentrated in or near melano-macrophage centres in all the organs studied . By this time, it had disappeared from the splenic ellipsoids, and the number of solitary A . hydrophila-immunoreactive cells had also decreased . At a later stage, antigen was located extracellularly at the membrane of cells in and around the melano-macrophage centres, and it remained so for a full year . No antigen was detected in the lymphoid organs following a bath immunization. Dev Comp Immunol, 1985 Winter, 9(1), 65 - 75 Humoral response and memory formation in carp after injection of Aeromonas hydrophila bacterin; Lamers CH et al.; The humoral immune response of carp (Cyprinus carpio) upon a bacterial fish pathogen Aeromonas hydrophila was studied in relation to memory formation . After a single intramuscular (i.m.) injection of formalin killed A . hydrophila cells (F-Ah), maximum serum Ab (Ab) titers were observed at day 20 . Distinct titers were still seen at day 360 in the groups injected with a medium or high antigen (Ag) dose (10(7) respectively 10(9) F-Ah) . The effect of a second immunization with a high Ag dose was studied in fish primed 1, 3, 8 or 12 months earlier with 10(5), 10(7) or 10(9) F-Ah . The height of the secondary Ab response was positively correlated with the height of the priming Ag dose . Challenge with a low Ag dose (10(6) F-Ah) gave the best results with 10(7) F-Ah primed animals . The highest secondary responses were obtained with combinations of corresponding priming and challenge dosages . It is concluded that fish are able to form immunological memory to this bacterial Ag . However, optimal memory levels are reached after a relative long period (3-8 months). J Infect, 1985 Jan, 10(1), 32 - 7 Pathogenicity of aeromonas; Brook I et al.; The ability of 15 Aeromonas sobria and 9 Aeromonas hydrophila isolates to cause subcutaneous lesions was tested . An inoculum of 10(11) colony forming units/l was injected subcutaneously into mice . Surviving animals developed a subcutaneous abscess and/or localised skin sloughing and loss of hair (alopecia) . An abscess was induced by all nine A . hydrophila isolates and by three of the 15 A . sobria isolates . The induction of local epidermal sloughing and loss of hair followed challenge with either A . hydrophila or A . sobria and correlated with the organisms' lethality for mice and their cytotoxicity in the Y-I adrenal cell assay . Local epidermal sloughing was not induced by the media used for growing the organisms or by sonicated cells of the isolates . The ability to cause epidermal sloughing was lost by incubating viable cells at 45 degrees C for 35 minutes . These yet unreported in vivo features of Aeromonas sp . may be useful in studies of the pathogenicity of the species as well as for rapid assay of toxicity of strains. J Bacteriol, 1985 Jan, 161(1), 463 - 5 Phospholipids and lipopolysaccharide of Aeromonas hydrophila; Howard SP et al.; The phospholipids and lipopolysaccharide of Aeromonas hydrophila were characterized . Phosphatidylethanolamine and phosphatidylglycerol were the major phospholipid components . The outer membrane contained more phosphatidylethanolamine and less phosphatidylglycerol than the inner membrane, and the phospholipids of the outer membrane contained a higher proportion of saturated fatty acids . Only four fatty acids (C14:0, C16:0, C16:1, and C18:1) were found in the phospholipids . The lipopolysaccharide of A . hydrophila did not contain the eight-carbon sugar 3-deoxyoctulosonic acid nor did it contain C16:0, both of which are typical constituents of the lipopolysaccharide of many other species. Circ Shock, 1985, 16(4), 395 - 404 Thromboxane, prostacyclin, and the hemodynamic effects of graded bacteremic shock; Slotman GJ et al.; This study investigates the interaction of thromboxane, prostacyclin, and the hemodynamic dysfunction of graded bacteremia . Arterial, venous, and pulmonary artery catheters were inserted into eight adult female pigs under barbiturate anesthesia . After a 60-min control period Aeromonas hydrophila (1.0 X 10(9)/ml) was infused intravenously at 0.2 ml/kg/hr, increasing gradually to 4.0 ml/kg/hr at 4 hr . Hemodynamic measurements, blood gases, and radioimmunoassay of thromboxane B2 (TxB) and prostaglandin 6-keto-F1 (PGI) were performed during the control period, at 10, 20, 30, 45, 60, 75, and 90 min of bacteremia and at 30-min intervals thereafter . During the bacterial infusion, cardiac index (CI), mean arterial pressure (MAP), paO2, pvO2, stroke volume (SV), and left ventricular stroke work (LVSW) decreased significantly, and pulmonary vascular resistance (PVR), pulmonary artery pressure (PAP), and intrapulmonary shunt (Qs/Qt) increased significantly . TxB was significantly increased at 30 min and remained elevated thereafter . PGI did not rise above control levels until after 240 min of bacterial infusion . TxB cross-correlated most frequently with CI, PVR, SV, paO2, and Qs/Qt, changes in TxB preceding the other variables by 0-60 min . PGI cross-correlated significantly with MAP, LVSW, CI, paO2, and Qs/Qt, changes in PGI preceding MAP, LVSW, and CI by 0-60 min, but following paO2 and Qs/Qt by 30-60 min . TxB is increased early in graded bacteremia and appears related to cardiorespiratory dysfunction . PGI increases late in graded bacteremia, following the onset of respiratory failure, and may mediate the arterial hypotension of septic shock. Dev Comp Immunol, 1985 Spring, 9(2), 251 - 60 Eosinophilic granular cells (EGC) and histamine responses to Aeromonas salmonicida toxins in rainbow trout; Ellis AE; The function of eosinophilic granular cells (EGCs) in salmonids is unknown . In a previous study of the pathogenesis of A . salmonicida, injection of crude exotoxins into rainbow trout were shown to reproduce the lesions associated with furunculosis and an accompanying lesion, the dispersion and degranulation of EGCs in the intestinal wall was reported . The present study investigated this phenomenon in relationship to the histamine content of the gut . In fish injected i/p with A . salmonicida exotoxins in a dose causing death in six hours, a coincidental decrease in the histamine content of the gut, appearance of histamine in the blood, and degranulation of the EGCs in the intestinal wall was observed 45 minutes post-injection . The fish developed behaviour patterns similar to that described by other workers for fish undergoing systemic anaphylaxis . Other features were pale gills, defaecation and widespread vasodilatation . The possible role of the EGC as a histaminogenic cell in rainbow trout is discussed. J Clin Microbiol, 1984 Dec, 20(6), 1221 - 2 Value of blood agar for primary plating and clinical implication of simultaneous isolation of Aeromonas hydrophila and Aeromonas caviae from a patient with gastroenteritis; Janda JM et al.; The simultaneous recovery of Aeromonas hydrophila and Aeromonas caviae from the stool of a 49-year-old woman with watery diarrhea was facilitated through the use of a blood agar medium which detected the hemolytic capability of A . hydrophila . In vitro phenotypic tests support the conclusion that only the A . hydrophila isolate was clinically significant. Am J Epidemiol, 1984 Dec, 120(6), 912 - 21 Prophylactic doxycycline for travelers' diarrhea in Thailand . Further supportive evidence of Aeromonas hydrophila as an enteric pathogen; Echeverria P et al.; A randomized double-blind study to determine the efficacy of a three-week course of doxycycline (100 mg daily) in preventing travelers' diarrhea was performed in 1980 among 63 United States Peace Corps volunteers during their first five weeks in Thailand, an area where doxycycline-resistant enterotoxigenic Escherichia coli are known to be common . Eight (24%) of 33 volunteers taking placebo and 3 (10%) of 30 taking doxycycline developed travelers' diarrhea for a calculated protection of 59%, but this was not statistically significant (p = 0.12) . Aeromonas hydrophila was isolated from 8 to 19 volunteers with either travelers' diarrhea or mild diarrhea in the placebo group, but from only 1 of 12 in the doxycycline group (p less than or equal to 0.05) . Furthermore, doxycycline significantly prevented colonization of the gastrointestinal tract with A . hydrophila while it was being taken (p less than or equal to 0.01) . Enterotoxigenic E . coli was isolated from only one volunteer with travelers' diarrhea in the placebo group and from none in the doxycycline group . Doxycycline prophylaxis of travelers' diarrhea in this geographic area, though not shown to be significantly protective, further supports the role of A . hydrophila as an enteric pathogen. J Antimicrob Chemother, 1984 Dec, 14(6), 575 - 9 Resistance of Aeromonas hydrophila to beta-lactam antibiotics; Zemelman R et al.; The activity of some beta-lactam antibiotics upon 20 strains of Aeromonas hydrophila and some properties of their beta-lactamases have been studied . High degree of resistance to benzylpenicillin and lower resistance to ampicillin and cephaloridine was observed . Clavulanic acid showed the highest activity . When clavulanic acid was assayed at subinhibitory concentrations in association with ampicillin . MICs of the latter decreased to two- to eight-fold . All strains produced inducible beta-lactamases with high activity upon ampicillin . A group of cephalosporinase-like enzymes was also found . Some beta-lactamases were inhibited by cloxacillin, and most of them were completely inhibited by 5 mg/l of clavulanic acid . Low impermeability of Aerom . hydrophila cells to beta-lactams was observed. J Hosp Infect, 1984 Dec, 5(4), 425 - 30 Aeromonas hydrophila: an outbreak of hospital infection; Mellersh AR et al.; Aeromonas hydrophila is a Gram-negative water-borne organism widely distributed in the environment . This organism is a recognized cause of diarrhoea and an opportunist pathogen in immunosuppressed patients . An outbreak of hospital-acquired infection which included three cases of pneumonia is reported . The organism was isolated from 19 patients. Eur J Biochem, 1984 Nov 15, 145(1), 107 - 14 Structure of the lipopolysaccharide core isolated from a human strain of Aeromonas hydrophila; Michon F et al.; Lipopolysaccharide was isolated from the cell-walls of a human strain of Aeromonas hydrophila by the aqueous phenol method in 0.58% yield (based on dry weight of bacteria) . The lipopolysaccharide consisted of SR-polysaccharide, core-oligosaccharide and lipid A; there was no O-specific polysaccharide . The core had the composition D-galactose, D-glucose, D-glycero-D-manno-heptose, L-glycero-D-manno-heptose and D-glucosamine in a molar ratio of 1:1:2:4:1 . Glucosamine was linked to an L-glycero-D-manno-heptose residue by a bond which was resistant to hydrolysis . The D-glucosamine-(1----7)-LD-heptose disaccharide was isolated and identified by the mass spectrum of its methylated alditol and the heptose residue not observed under normal hydrolysis conditions was easily determined after deamination of the complete core . Methylation analysis, chemical degradation, periodate and chromium trioxide oxidations and nuclear magnetic resonance (13C and 1H NMR) spectroscopy were used to identify the structure of the core oligosaccharide as: (formula: see text) Can J Biochem Cell Biol, 1984 Nov, 62(11), 1064 - 71 Surface layer virulence A-proteins from Aeromonas salmonicida strains; Kay WW et al.; Superficial surface layer proteins (A-proteins) were present on diverse isolates of Aeromonas salmonicida which differed both physiologically and in pathogenesis . Three of these proteins were purified directly from the surface of whole cells or from outer membrane preparations . These A-proteins were unusually hydrophobic (45-47%) and of similar but not identical molecular mass (49, 50, and 51 kdaltons) . They were nearly identical in amino acid composition and were highly conserved, but not identical with respect to their hydrophobic N-terminal amino acid sequences . These proteins differed, however, with respect to their oligomerization properties, isoelectric forms, and chymotryptic peptide patterns . All three proteins were immunologically closely related and shared surface-exposed immunoreactive peptides with 28 separate isolates. J Pediatr Gastroenterol Nutr, 1984 Nov, 3(5), 808 - 11 Aeromonas hydrophila colitis in a child; Marsik F et al.; A 5-year-old girl presented with chronic bloody diarrhea . Evaluation including sigmoidoscopy, rectal biopsy, and barium enema was consistent with the diagnosis of ulcerative colitis . Culture of the stool grew Aeromonas hydrophila . A . hydrophila colitis may be more common than presently realized. Infect Immun, 1984 Nov, 46(2), 435 - 41 Cloning of enterotoxin gene from Aeromonas hydrophila provides conclusive evidence of production of a cytotonic enterotoxin; Chakraborty T et al.; Culture filtrates of two Aeromonas hydrophila strains which were isolated from patients with diarrhea and assumed to be causative agents of the infections were shown to contain enterotoxic, cytotoxic, and hemolytic activities . Modest heat treatment of the filtrates inactivated the cytotoxic and cytolytic activities, but not the enterotoxic activity . The construction of cosmid gene banks in Escherichia coli of DNA from both A . hydrophila strains demonstrated that the determinants of the three activities are located on three different segments of the A . hydrophila chromosome . Both heated culture filtrates of A . hydrophila and nonheated filtrates of an E . coli clone containing the A . hydrophila enterotoxin gene provoked fluid accumulation in the rabbit ileal loop and suckling mouse models and caused elongation of Chinese hamster ovary cells . Differences in the responses of the models to the A . hydrophila enterotoxin and to the heat-labile and heat-stabile toxins of E . coli indicated that the former is distinct from the latter two types of toxin . These results constitute conclusive evidence for the production by A . hydrophila of a cytotonic enterotoxin that is distinct from the A . hydrophila cytotoxin and hemolysin and known E . coli enterotoxins. Appl Environ Microbiol, 1984 Oct, 48(4), 865 - 7 Isolation of enterotoxigenic, hemolytic, and antibiotic-resistant Aeromonas hydrophila strains from infected fish in Bangladesh; Rahim Z et al.; Strains of Aeromonas hydrophila isolated from skin infections of common freshwater fish in Bangladesh were tested for enterotoxin production, hemolysin production, and any correlation between these two activities . We also tested the resistance patterns of A . hydrophila to different drugs, especially in relation to ampicillin . The A . hydrophila strains produced an enterotoxin that was related to their beta-hemolytic activities . Production of beta-hemolysin may thus be an indicator of enterotoxicity . As 50% of the strains of A . hydrophila were found to be susceptible to 12.5 micrograms of ampicillin per ml, media containing this antibiotic may not be suitable for their isolation. Infect Immun, 1984 Oct, 46(1), 122 - 7 Purification and some properties of Aeromonas hydrophila hemolysin; Asao T et al.; A hemolysin produced by a strain of Aeromonas hydrophila isolated from a patient with diarrhea was purified by acid precipitation and quarternary aminoethyl-Sephadex chromatography . The molecular weight of the hemolysin was estimated at 50,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and at 48,000 by Sephadex G-100 gel filtration . In polyacrylamide gel electrophoresis at pH 4.0 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the hemolysin migrated as a single band, whereas electrophoresis at pH 9.4 and thin-layer isoelectric focusing demonstrated multiple bands . The results may indicate charge isomers of the hemolysin . The purified hemolysin had a hemolytic activity of 134 hemolytic units per microgram of protein on rabbit erythrocytes . It caused fluid accumulation in infant mouse intestines and rabbit ligated ileal loops . Purified hemolysin also elicited cytotoxicity to Vero cells and lethal toxicity to mice . All these biological activities were lost on heating for 5 min at 56 degrees C . These findings support the notion that A . hydrophila hemolysin is a cytotoxic enterotoxin. Arch Intern Med, 1984 Oct, 144(10), 2078 - 9 Pyogenic meningitis manifesting during therapy for Aeromonas hydrophila sepsis; Ellison RT 3rd et al.; Pyogenic meningitis became apparent on the third day of ampicillin and gentamicin therapy for Aeromonas hydrophila sepsis in a patient with severe alcoholic hepatitis . The patient responded clinically to therapy with intravenous cefotaxime sodium and gentamicin sulfate . Antibiotic therapy that provides adequate CSF concentrations should be considered in the treatment of patients with Aeromonas sepsis. J Trauma, 1984 Sep, 24(9), 803 - 10 Thromboxane interaction with cardiopulmonary dysfunction in graded bacterial sepsis; Slotman GJ et al.; The relationship between plasma levels of thromboxane A2, radioimmunoassayed as thromboxane B2 (TxB), and cardiopulmonary dysfunction in graded bacterial sepsis was investigated . Five adult female pigs under anesthesia were intubated and allowed to breathe room air spontaneously . Femoral arterial, venous, and pulmonary artery catheters were inserted . After a 60-minute control period Aeromonas hydrophila (1.0 X 10(9)/ml) was infused intravenously at 0.2 ml/kg/hr, gradually increasing to 4.0 ml/kg/hr over 4 hours . Arterial and mixed venous blood gases, hemodynamic measurements, and TxB plasma concentrations were obtained during the control period, at 10, 20, 30, 45, and 60 minutes and at 30-minute intervals thereafter . Cardiac index increased significantly from control at 20 minutes, remained above control levels for 1 hour, and then declined to significantly low values at 150 minutes . TxB was increased from control at 20 minutes, rising to four times control at 120 minutes . Mean arterial pressure, pulmonary capillary wedge pressure, left ventricular stroke work, paO2, and pvO2 decreased significantly during the experiment . Pulmonary artery pressure and pulmonary vascular resistance increased significantly . Changes in TxB were significantly cross-correlated with changes in cardiac index, pulmonary vascular resistance, stroke volume, left ventricular stroke work, and paO2 . TxB elevations led the cross-correlated variables by 0 to 60 minutes . Pulmonary vascular resistance cross-correlated with mean arterial pressure and cardiac index . TxB is increased early in graded bacterial sepsis . Changes in TxB appear to precede impaired cardiopulmonary function . The data suggest that TxB is involved in the detrimental hemodynamic effects of early septicemia. Can J Microbiol, 1984 Sep, 30(9), 1190 - 2 {Demonstration of a proteolytic activity on intracellular origin in Aeromonas hydrophila LP 50}; Denis F et al.; Aeromonas hydrophila LP 50, isolated from packaged pasteurized milk, was grown in glucose-polypeptone medium at 30 degrees C . The proteolytic activity of A . hydrophila LP 50, optimum at the stationary phase of growth, is attributed to extracellular or membrane protease; no intracellular proteolytic activity was shown. Appl Environ Microbiol, 1984 Aug, 48(2), 456 - 8 Effects of short-term cold storage on recovery of proteases from extracellular products of Aeromonas hydrophila; Amborski RL et al.; Three protease-containing fractions were recovered by gel filtration from concentrated crude extracellular products produced by Aeromonas hydrophila grown in a defined medium . The recovery of a heat-stable protease was differentially prevented when the crude preparation was stored for 48 h at -20 degrees C but was unaffected by storage of the crude preparation at either 4 or -70 degrees C . Once fractionated, the heat-stable protease appeared to be unaffected by subsequent storage at 4, -20, or -70 degrees C. Appl Environ Microbiol, 1984 Aug, 48(2), 361 - 6 Isolation of Aeromonas hydrophila from a metropolitan water supply: seasonal correlation with clinical isolates; Burke V et al.; The occurrence of Aeromonas spp . in the metropolitan water supply of Perth, Western Australia, Australia, was monitored at several sampling points during a period of 1 year . Water within the distribution system conformed to international standards for drinking water but contained Aeromonas spp . in numbers comparable to those in raw surface water, although this water was free of Escherichia coli . Coliforms and E . coli were found in raw surface waters, and Aeromonas spp . were found in raw water from surface and underground sources . Chemical treatment, followed by chlorination at service reservoirs, resulted in water free of E . coli and a decrease in the number of Aeromonas spp . Aeromonas spp . were found in the greatest numbers in summer . Multiple regression analysis showed that growth of Aeromonas spp . in chlorinated water was related to water temperature, residual chlorine, and interaction between these variables . The incidence of Aeromonas-associated gastroenteritis, determined from isolates referred to us for enterotoxin testing, paralleled the pattern of isolation of Aeromonas spp . in water within the distribution systems . We suggest that the presence of Aeromonas spp . in drinking water needs public health appraisal and that further work should be undertaken to permit reevaluation of standards for the quality of drinking water. Avian Dis, 1984 Jul-Sep, 28(3), 804 - 7 The occurrence of Aeromonas hydrophila in avian diagnostic submissions; Shane SM et al.; Twenty isolations of Aeromonas hydrophila were made from 15 species of free-living, commercial, and companion birds submitted for routine diagnostic postmortem examination . Seventy percent of the isolations were made from November through March during the 25-month survey period. Can J Microbiol, 1984 Jul, 30(7), 900 - 4 Difference in the extracellular products of two strains of Aeromonas hydrophila virulent and weakly virulent for fish; Lallier R et al.; In this study we first compared the toxigenic profile of Aeromonas hydrophila strains virulent and weakly virulent for rainbow trout . The separation of the toxic factor for fish is also described . Both strains produced hemolytic, enterotoxic, and dermonecrotic activities; the weakly virulent strain produced 20 times more hemolysin . Only the cell-free supernatant of the virulent strain produced a toxic factor for fish . After passage on Sephacryl S-200, the toxic factor for fish was separated from the hemolysin . This toxic factor is heat labile. Jpn J Med Sci Biol, 1984 Jun, 37(3), 141 - 4 Production of cholera-like enterotoxin by Aeromonas hydrophila; Shimada T et al.; A total of 249 strains of mesophilic Aeromonas including 179 A . hydrophila and 70 A . caviae were tested for production of cholera-like enterotoxin by reversed passive latex agglutination (RPLA) assay . A cholera-like enterotoxin neutralized with cholera antitoxin was demonstrated in the culture filtrates from eight (4.5%) of the 179 A . hydrophila strains, while none of A . caviae strains revealed the enterotoxin production in the test . Production of the cholera-like enterotoxin in the eight strains of A . hydrophila was also confirmed by enzyme-linked immunosorbent assay (ELISA). Onderstepoort J Vet Res, 1984 Jun, 51(2), 91 - 4 Furunculosis in rainbow trout (Salmo gairdneri) raised in sea water; Boomker J et al.; Ulcerative skin lesions were encountered in rainbow trout raised in sea water by a commercial concern in the Western Cape, South Africa . Grossly, the lesions resembled furunculosis but, histopathologically, they differed from typical furunculosis in that bacterial colonies were rarely found in the organs, and also the kidneys and spleens were minimally involved . The causative organism was identified as an achromogenic Aeromonas salmonicida that shared characteristics with all 3 subspecies, salmonicida, masoucida and achromogenes . This is the first report of an outbreak of this disease in South Africa. J Hosp Infect, 1984 Jun, 5(2), 205 - 9 The use of a biotyping system to investigate an unusual clustering bacteraemias caused by Aeromonas species; Cookson BD et al.; Aeromonas spp . were isolated from blood cultures taken from four clinically bacteraemic patients over an 18 day period on four separate wards . A common source was suspected and extensive environmental sampling revealed two more ward isolates of Aeromonas spp . A biotyping system was employed which distinguished the strains from each other and indicated that a common source was unlikely . This coincidental clustering occurred in the autumn, a period when isolates from water and faeces are normally at a peak . All patients were debilitated and it is postulated that their own gastrointestinal tracts acted as the most likely route for their bacteraemias. Presse Med, 1984 May 5, 13(19), 1203 - 5 {Aeromonas hydrophila septicemia . Epidemiologic aspects . 15 cases}; Picard B et al.; Fifteen cases of Aeromonas hydrophila septicaemia, characterized by their frequent pulmonary lesions and the severity of their course, are reported . The delay observed between admission to hospital and first symptoms, together with the presence of anatomical lesions or physiological disturbances suggesting bacterial invasion by the intestinal route, have led the authors to postulate a nosocomial digestive contamination, probably from water, as suggested by the particular ecology of this micro-organism . This hypothesis was supported by the finding of Aeromonas hydrophila in large numbers at the different points of the hospital water distribution system where samples were taken. Eur J Immunol, 1984 May, 14(5), 442 - 7 Immunodominant protein epitopes . I . Induction of suppression to hen egg white lysozyme is obliterated by removal of the first three N-terminal amino acids; Wicker LS et al.; The lack of response to hen egg white lysozyme (HEL) by C57BL (H-2b) mice has been demonstrated previously to be related to the induction of suppressor T (Ts) cells which recognize the amino terminal region of HEL . In this report, the nature of the protein determinant required for Ts cell induction is more precisely detailed using des-1,2,3-HEL (AP-HEL) prepared with an aminopeptidase purified from Aeromonas proteolytica . Remarkably, the removal of just these three amino acids obliterates the ability of HEL to induce Ts cells specific for HEL . Additionally, in contrast to HEL, AP-HEL is able to prime for an in vitro T cell proliferative response to either AP-HEL or HEL . Thus, removal of a very limited region of a protein antigen can drastically alter its immunogenic properties. J Bacteriol, 1984 Apr, 158(1), 16 - 22 Str