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Biomedical subjects

J M Janda

Publications and source records attributed to J M Janda.

At least 91 records · Page 5Linked to original sources
PubMed1988

Surface properties of autoagglutinating mesophilic aeromonads.

The surface characteristics of 24 autoagglutinating (AA+) mesophilic aeromonads were investigated. One group of 16 was found to be highly related serologically by their reactive pattern against O antisera generated against three reference strains. Subsequent characterization of 11 of these isolates (group 1) indicated that they had the following properties in common: precipitation after boiling (PAB+), membership of serogroup O:11 (typing scheme of Sakazaki and Shimada), resistance to lysis by bacteriophage Aeh1, and possession of a surface layer (S layer) as determined by transmission electron microscopy. Strains not exhibiting the same serologic reactivity pattern belonged to diverse serogroups (other than O:11), were generally susceptible to lysis by Aeh1, and were S layer negative by transmission electron microscopy (group 2). Analysis of selected isolates representing both groups indicated that group 2 strains were usually more hydrophobic than group 1 isolates in several different assays; both groups, however, possessed high surface charge as determined by binding to DEAE-cellulose. Group 1 isolates were more virulent than group 2 strains tested as determined by lower 50% lethal doses for mice. On the basis of the results of the kinetics of autoagglutination in broth, relative surface hydrophobicity, uptake of Congo red, agglutination of yeast cells, and electrophoretic protein profiles of whole-cell extracts, the surface layer associated with O:11 mesophilic aeromonads appears to be distinct from that of Aeromonas salmonicida. The results suggest that a new pathogenic group of mesophilic aeromonads linked through a common AA phenotype, serogroup, and S layer cause serious infections in both humans and animals (fish).

Aeromonas↗
PubMed1988

Quality control of individual components used in Middlebrook 7H10 medium for mycobacterial susceptibility testing.

The acceptability of different lots of commercial components which constitute our basal medium for susceptibility testing of mycobacteria was evaluated. The basal medium consisted of Middlebrook 7H10 agar supplemented with 10% oleic acid-albumin-dextrose-catalase and 0.5% glycerol. Studies were performed by using three separate microbiologic assays, and results were compared with parallel tests on previously standardized and acceptable lots of media. Components were rejected if comparison with standardized medium showed a major change in growth support or susceptibility status of any reference strain to any antimicrobial agent tested. Of the components tested in such a manner, 7 of 23 (30%) lots of 10% oleic acid-albumin-dextrose-catalase, 2 of 13 (15%) lots of Middlebrook 7H10 agar, and 0 of 5 lots of glycerol were found to be unacceptable. This study demonstrates that individual lots of components of this basal medium may vary significantly in their suitability for susceptibility testing, and failure to detect such variation may dramatically affect susceptibility profiles.

Anti-Bacterial Agents↗
PubMed1987

Characterization and use of a DNA probe as an epidemiological marker for Pseudomonas aeruginosa.

We used DNA restriction fragments, derived from the exotoxin A gene and surrounding sequences, as an epidemiological marker for Pseudomonas aeruginosa. Using these DNA fragments as probes in Southern blot hybridizations and/or total genomic digestions, we were able to distinguish greater than 100 different strains of P. aeruginosa. The stability of the marker in vitro was established by using well-characterized strains, which were stored under different conditions and subjected to chemical mutagenesis. The stability of the marker within a given strain in vivo was established during experimental infection in the chronic rat lung model of pseudomonas pneumonia. P. aeruginosa serially cultured from individual patients with cystic fibrosis were examined by using this marker. Isolates that varied in colonial morphology, serotype, and biotype were identical when analyzed by Southern blot hybridization using the fragment as a probe. Indistinguishable isolates (by serotyping, biotyping, and antibiograms) cultured from two unrelated patients were easily distinguished by using Southern blot analysis.

ADP Ribose Transferases↗
PubMed1987

Detection, quantitation and stability of the beta haemolysin of Aeromonas spp.

Amongst 58 isolates of motile aeromonads evaluated for the ability to produce beta haemolysin, haemolytic activity was significantly associated with strains belonging to the Aeromonas hydrophila and A. sobria groups. Of erythrocytes from nine animal species tested, mouse red blood cells provided the best indicator system for detection of beta-haemolysin activity. Furthermore, differences in the stability of the beta haemolysins of selected A. sobria and A. hydrophila isolates at different temperatures, and in the presence of urea or dithiothreitol were observed.

Aeromonas↗
PubMed1987

Use of sodium dodecyl sulfate-polymyxin B-sucrose medium for isolation of Vibrio vulnificus from shellfish.

The differential and selective sodium dodecyl sulfate-polymyxin B-sucrose medium (SPS) of Kitaura et al. (T. Kitaura, S. Doke, I. Azuma, M. Imaida, K. Miyano, K. Harada, and E. Yabuuchii, FEMS Microbiol. Lett. 17:205-209, 1983), which highlights alkylsulfatase activity, was evaluated for its potential use in the direct isolation and enumeration of Vibrio vulnificus from shellfish. V. vulnificus was detected by this method in six of nine shellfish samples collected from diverse geographic locales during the summer of 1986. Direct enumeration of V. vulnificus at 7.0 X 10(2) to 2.2 X 10(4) CFU/g of shellfish was achieved on SPS agar. All sample results were confirmed in parallel examinations by using conventional glucose-salt-Teepol (Shell Oil Co.) broth and alkaline peptone water enrichment with plating onto thiosulfate-citrate-bile salts-sucrose agar. Additionally, alkylsulfatase activity was evaluated in vitro for 97 strains representing 14 Vibrio spp. V. vulnificus and Vibrio cholerae-01 were the only species consistently found to possess this activity. The range of plating efficiencies for random V. vulnificus strains analyzed on SPS was 11 to 74% (mean, 39%). The use of SPS shows great promise for the study of shellfish and other environmental sources for V. vulnificus.

Animals↗
PubMed1987

Virulence markers of mesophilic aeromonads: association of the autoagglutination phenomenon with mouse pathogenicity and the presence of a peripheral cell-associated layer.

Autoagglutination (AA phenotype) of mesophilic aeromonads in broth was found to be a virulence-associated marker. There were two kinds of AA+ strains: those that spontaneously pelleted (SP+), and those that pelleted only after boiling (PAB+). Of 79 strains tested, 24 (30%) were AA+, and 18 of these were recovered from clinical specimens. Most of the AA+ strains (n = 21) were identified as either Aeromonas sobria or Aeromonas hydrophila. Of the well-documented clinical isolates of A. sobria and A. hydrophila available, 5 (46%) of 11 from invasive disease and 4 (14%) of 29 from noninvasive disease were SP- PAB+. The SP- PAB+ phenotype was significantly associated with invasive infections (e.g., bacteremia and peritonitis [chi 2, P less than 0.05]). All seven of the SP- PAB+ A. sobria and A. hydrophila strains tested killed mice within 48 h after intraperitoneal infection with 1 x 10(7) to 3 x 10(7) CFU, whereas only two of four SP+ PAB+ strains tested were lethal. All of the SP- PAB+ A. sobria and A. hydrophila isolates examined shared common O somatic antigens and possessed an external layer peripheral to the cell wall as determined by thin-section electron micrography. The LL1 strain of A. hydrophila used by Dooley et al. (J. S. G. Dooley, R. Lallier, and T. J. Trust, Vet. Immunol. Immunopathol. 12:339-344, 1986) to demonstrate an S membrane protein component in aeromonads virulent for fish also was SP- PAB+ and possessed the peripheral membrane, suggesting an association between these two components. Seven AA- and three SP+ strains tested lacked this layer; furthermore, 22 (71%) of 31 such isolates did not kill mice. The AA phenotype was a stable characteristic upon long-term passage of isolates in vitro. Study of SP+ and PAB+ aeromonads by surface charge and hydrophobicity analyses indicated that neither property correlated with either virulence or the presence of an external layer.

Acriflavine↗
PubMed1987

Effect of acidity and antimicrobial agent-like compounds on viability of Plesiomonas shigelloides.

Nineteen Plesiomonas shigelloides strains were evaluated for their stability at acidic and slightly alkaline pHs and for their susceptibility to antimicrobial agent-like compounds produced by enteric flora. Most P. shigelloides isolates were rapidly inactivated under high-acid (pH 4 or less) conditions. Screening of enteric bacteria for elaboration of factors active against P. shigelloides revealed two organisms (Pseudomonas aeruginosa and Streptococcus [Enterococcus] faecium) capable of secreting such inhibitory substances. The results of this study suggest some factors potentially important in regulating gastrointestinal colonization by P. shigelloides from environmental sources.

Anti-Bacterial Agents↗
PubMed1986

Growth of Aeromonas species on enteric agars.

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.

Aeromonas↗
PubMed1986

Elastolytic activity among staphylococci.

A total of 161 isolates of the genus Staphylococcus were evaluated for the ability to produce elastase. Elastase activity was detected only in S. epidermidis strains (sensu stricto), being absent in S. aureus isolates and other coagulase-negative staphylococci tested. The elastase elaborated by S. epidermidis isolates appeared to be an inducible enzyme whose synthesis was medium dependent.

Culture Media↗
PubMed1986

Pseudomonas maltophilia exoenzyme activity as correlate in pathogenesis of ecthyma gangrenosum.

Ecthyma gangrenosum has not been described during the course of blood stream invasion with Pseudomonas maltophilia, although it occurs with a 30% frequency in Pseudomonas aeruginosa septicemia. We isolated P. maltophilia from the blood and an ecthyma lesion in a leukemic patient. The organism was an avid protease and elastase producer and hence mimicked the exoenzyme profile of invasive P. aeruginosa. The patient responded to moxalactam to which the isolate was susceptible in vitro. On the basis of this report, P. maltophilia may be included among an emerging number of gram-negative bacillary species capable of producing severe cutaneous manifestations of bacteremia.

Aged↗
PubMed1986

The interaction of complement components with Aeromonas species.

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.

Aeromonas↗
PubMed1985

Biochemical and exoenzymatic properties of Aeromonas species.

One hundred twenty-seven isolates of Aeromonas comprising the three currently recognizable species (A. hydrophila, A. sobria, and A. caviae) were evaluated for biochemical and exoenzymatic properties. Aeromonas species were generally (greater than 90%) characterized as gram-negative fermentative rods that were oxidase-, catalase-, and beta-galactosidase-positive, produced arginine dihydrolase, and failed to decarboxylate ornithine. More than 95% of all isolates tested failed to grow on 6.5% salt or thiosulfate-citrate bile salts agar and were resistant to the vibriostatic agent 0/129. Most Aeromonas species produced acid from hexoses while failing to ferment alcoholic sugars or trisaccharides. In exoenzymatic studies, Aeromonas species were uniformly found to produce several exoenzymes, including amylase, DNase, RNase, esterase, lipase, gelatinase, protease, fibrinolysin, and chitinase. Within the genus, a number of biochemical and enzymatic properties were found to be associated with one or more of the taxonomically recognizable species. These properties included glycoside utilization, Heiberg grouping based upon fermentation of arabinose, sucrose, and mannose, and the elaboration of several extracellular enzymes (elastase, hemolysin, lecithinase, phosphatase). In addition, phenotypic markers previously associated with enterotoxigenic Aeromonas isolates were almost exclusively found among A. hydrophila and A. sobria species, suggesting that these species are the major enteric pathogens.

Aeromonas↗
PubMed1985

In vitro susceptibilities of Aeromonas hydrophila, Aeromonas sobria, and Aeromonas caviae to 22 antimicrobial agents.

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.

Aeromonas↗
PubMed1985

Isolation of Serratia plymuthica from a human burn site.

The saprophytic bacterium Serratia plymuthica was recovered from a facial wound (burn) site of a pediatric patient. The clinical significance of the organism was undetermined due to its apparent eradication from this location by therapy with topical 1% silver sulfadiazine. Seeding of the burn with S. plymuthica may have occurred from contaminated moisture sometimes found on and around steam radiators.

Burns↗