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Biomedical subjects

J M Janda

Publications and source records attributed to J M Janda.

At least 109 records · Page 6Linked to original sources
PubMed1985

Assessment of plasmid profile, exoenzyme activity, and virulence in recent human isolates of Yersinia enterocolitica.

We examined a group of 23 recent clinical isolates of Yersinia enterocolitica recovered from symptomatic patients residing in the New York, N.Y. area. These isolates were tested for the presence of plasmids, exoenzyme activity, mouse lethality, and phenotypic properties postulated to correlate with virulence. Of the 23 isolates, 17 harbored a 60- to 65-kilobase (kb) plasmid. Six isolates were lethal for white mice, showed the phenotypic markers of autoagglutination and calcium dependence for growth at 37 degrees C, and contained a 60- to 65-kb plasmid. Restriction endonuclease analysis with several different enzymes revealed the presence of three distinct plasmid profiles in these isolates. Isolates with a single plasmid of 60 to 70 kb, typical for this species, were detected, but these were of three distinct types as judged from restriction enzyme digestion. One strain was unusual among clinical isolates of Y. enterocolitica in that it contained at least four distinct plasmids. In addition, this nontypable strain showed exoenzymatic activity similar to that of serogroup O8 isolates, was not lethal to mice, and did not require calcium for growth at 37 degrees C.

Animals↗
PubMed1985

Cephalothin susceptibility as a potential marker for the Aeromonas sobria group.

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.

Aeromonas↗
PubMed1984

Diagnosis of herpesvirus infections: correlation of Tzanck preparations with viral isolation.

Evaluation of Giemsa-stained smears of scrapings from the base of vesicles or ulcers ( Tzanck preparation) for the presence of multinucleated giant cells and/or intracellular inclusions were diagnostic for herpesvirus in 18 of 21 cases (86%) of culturally proved herpesvirus infections. Smears from four patients with varicella-zoster infection also revealed cytologic alterations characteristic of herpesvirus.

Diagnostic Errors↗
PubMed1984

Hemagglutination patterns of Aeromonas spp. in relation to biotype and source.

Aeromonas spp. show patterns of hemagglutination with human group O cells in the presence of fucose, galactose, and mannose. These patterns are related to biotype as well as to the source of isolates. There was good correlation between hemagglutination pattern and the presence of diarrhea among strains isolated in Western Australia, which was the only source with adequate data for classification of children with an without diarrhea. Most of the environmental and other nonfecal isolates produced patterns different from those in strains associated with diarrhea. These results suggest that hemagglutinins should be considered with enterotoxins as virulence factors in Aeromonas spp.

Aeromonas↗
PubMed1984

Biotyping of Aeromonas isolates as a correlate to delineating a species-associated disease spectrum.

A group of 147 Aeromonas isolates from diverse clinical and environmental sources was subjected to the biotyping scheme of Popoff and Veron. Of the 147 isolates biotyped, 137 (93%) could be identified, with Aeromonas hydrophila predominating (48%) and equal percentages (25 to 27%) of the other two species (Aeromonas sobria and Aeromonas caviae). A number of additional biochemical properties were found to be significantly associated with one or more of these three species. These included lysine decarboxylase activity, hemolysis of sheep erythrocytes, lecithinase production, staphylolytic activity, arbutin hydrolysis, and acid production from utilization of various carbohydrates. By incorporating these phenotypic properties into an extended biotyping system, 98% of the isolates were identified. Selective distribution of individual species with respect to certain body sites was noted.

Aeromonas↗
PubMed1984

Comparative studies and laboratory diagnosis of Vibrio vulnificus, an invasive Vibrio sp.

Vibrio vulnificus was isolated from a bacteremic patient. This strain, together with other isolates of V. vulnificus, was compared with V. alginolyticus, V. fluvialis, and V. parahaemolyticus with regard to growth characteristics on enteric agar media (enabling isolation and identification) and production of exoenzymes which could correlate with invasive potential. V. vulnificus grew well on MacConkey. Endo, xylose-lysine deoxycholate, and Hektoen enteric agar plates. Because V. vulnificus colonies resembled those of lactose-fermenting strains of the family Enterobacteriaceae, however, isolation of this vibrio from mixed specimens or stools may require the use of thiosulfate-citrate-bile salts-sucrose agar. V. vulnificus produced numerous exoenzymes (protease, DNase, lipase, and esterase) but not elastase or lecithinase. Although differences in exoenzyme production were observed among the four vibrio species, no single exoenzyme could be linked to the invasive potential of V. vulnificus.

Aged↗
PubMed1984

Phenotypic factors correlated with the absence of virulence among gentamicin-resistant Pseudomonas aeruginosa strains.

Previous reports have suggested that clinical strains of gentamicin-resistant Pseudomonas aeruginosa (GRPA) generally produce only superficial infections (wounds, urinary tract infections) in contrast to their more invasive gentamicin-susceptible counterparts (GSPA). In view of this finding, a comparative study of a number of phenotypic properties of 20 GRPA and GSPA strains (10 isolates) was assessed to determine how closely related these two populations are and how their phenotypic properties might reflect virulence. GRPA isolates were found to be more adherent to buccal cells than their susceptible counterparts (P = 0.0001). Motility, however, was generally restricted in the GRPA population when compared with GSPA isolates (P = 0.02), although on the basis of zone diameters, some strains overlapped into the other group. Enzymatically, GSPA isolates produced significantly more lipase activity against C-14 lipids than GRPA strains (P = 0.04). No differences were recorded between the two populations in dye sensitivity or in their ability to grow on minimal media at 37 and 42 degrees C. Only 35% of the GRPA isolates agglutinated in 1 of the 17 monospecific antisera reactive for P. aeruginosa. The results of this study suggest that in vivo-generated GRPA strains possess phenotypic properties intermediate between those described for in vitro-derived GRPA isolates and their progenitor GSPA strains. The increased adherence of clinical GRPA isolates to buccal cells may explain their predilection to produce wound and urinary tract infections, whereas their lack of systemic dissemination may be partially due to decreased motility and to reduced lipase production.

Adhesiveness↗
PubMed1984

Biotyping and exoenzyme profiling as an aid in the differentiation of human from bovine group G streptococci.

Group G streptococci were isolated from throat and extrapharyngeal cultures from 75 patients during an 18-month period. Of 29 throat isolates, 18 were recovered from patients with pharyngitis, 8 were of unknown significance, and 3 were of questionable etiology. Clinical significance could be ascribed to 13 of 46 extrapharyngeal isolates recovered from wound, urinary tract, blood, and conjunctival cultures. Extrapharyngeal isolates recovered from stool, sputum, and vaginal cultures were considered nonsignificant. A total of 96 group G streptococcal strains (including 21 human and 14 bovine strains from outside sources) were tested for exoenzyme production and subjected to a large battery of biochemical tests. Bovine and human isolates could be distinguished on the basis of trehalose fermentation, litmus milk reduction, and production of beta-D-glucuronidase, hyaluronidase, and fibrinolysin. Eight distinct biotypes could be discerned on the basis of fermentation of trehalose, raffinose, and lactose and esculin hydrolysis. All isolates that fermented raffinose were associated with infection. These results support the concept of two distinctly different epidemiological reservoirs of group G streptococci in humans and bovines.

Animals↗
PubMed1984

Value of blood agar for primary plating and clinical implication of simultaneous isolation of Aeromonas hydrophila and Aeromonas caviae from a patient with gastroenteritis.

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.

Aeromonas↗
PubMed1983

Aeromonas species in clinical microbiology: significance, epidemiology, and speciation.

Over a one-year period, 32 strains (31 clinical, 1 environmental) of Aeromonas sp. were recovered. Chief sources of isolation were the gastrointestinal tract (48%), wounds (19%), and blood (13%). Gastrointestinal isolates were most often recovered from young (less than 5 yrs) children with diarrhea; wound or blood isolates were recovered more often from an older (avg. 56 yrs) population with one of several underlying disorders. Regardless of body site of isolation, most strains of Aeromonas appeared to be community acquired and not nosocomially transmitted. Over 70% of all isolates recovered during this year period were isolated during summer or fall months, suggesting a seasonal distribution of this microorganism. Speciation of Aeromonas isolates revealed A. hydrophila to be the predominant species isolated from clinical specimens, although significant percentages of other Aeromonas sp. were also recovered from clinical material.

Adult↗
PubMed1983

Morphologic aberration associated with colonial tenacity of Pseudomonas aeruginosa.

A blood isolate of Pseudomonas aeruginosa was encountered which produced, on subculture to Mueller-Hinton agar, markedly adherent, tenacious colonies which were characterized microscopically by the presence of serpentine rows of interlocking bacilli. Factors accounting for the observed morphologic aberration, which was lost upon subculture, remain unknown.

Agar↗
PubMed1983

Phenotypic markers associated with gastrointestinal Aeromonas hydrophila isolates from symptomatic children.

Aeromonas hydrophila gastroenteritis was detected in 12 pediatric patients during a 5-month period. Chief complaints included bloody diarrhea, fever, vomiting, and abdominal pain. Severe symptoms in two patients necessitated hospitalization and supportive care. Phenotypic characteristics associated with enterotoxigenicity of A. hydrophila strains demonstrated that all 12 isolates were cytotoxic to HeLa cells and most were lysine decarboxylase positive (75%). A correlation existed between the presence of the five virulence-associated markers of two isolates of A. hydrophila and the severity of disease. Although the length and symptoms of gastroenteritis varied among all 12 patients, most had self-limiting diarrhea. The frequent occurrence of A. hydrophila gastroenteritis in pediatric patients warrants a greater appreciation of this agent as a significant cause of diarrhea, especially in summer.

Adolescent↗
PubMed1983

Correlation of enterotoxicity with biotype in Aeromonas spp.

Enterotoxin production correlated with biotype in a study of 686 strains of Aeromonas spp. from Indonesia, Thailand, the United States, and Western Australia. Most strains were isolated from feces but nonfecal human isolates and environmental strains were also included. More than 80% of Voges-Proskauer (VP)-positive strains, classified as A. hydrophila, were enterotoxigenic in the suckling mouse assay as were 90% of VP-positive, arabinose-negative strains. An association between positive VP, arabinose fermentation, and failure to produce enterotoxins was found only with environmental strains. VP-negative strains which did not oxidize gluconate or produce gas from glucose were classified as A. punctata subsp. caviae. Only 2 of the 286 strains produced enterotoxins, and both were from Indonesian fecal samples. There were few remaining VP-negative strains, classified as A. punctata subsp. punctata and, of these, about half were enterotoxigenic. Regardless of source and species, 97% of Aeromonas spp. were correctly classified in relation to enterotoxin production with a hemolysin assay. A combination of biochemical testing and hemolysin assay should be suitable for diagnostic laboratories to identify enterotoxigenic Aeromonas spp. which, in children, are associated with diarrhea, unlike non-enterotoxigenic strains.

Aeromonas↗
PubMed1982

Recovery of Pseudomonas aeruginosa colonial dissociants on a protease detection medium.

Dialyzed brain heart infusion-skim milk agar medium facilitated the recovery of colonial dissociants of Pseudomonas aeruginosa. Differences in colonial morphology as well as in proteolytic activity were readily visualized, thus permitting facile isolation of segregating colony types for further biochemical, serological, and susceptibility studies.

Bacteriological Techniques↗
PubMed1982

Pseudomonas aeruginosa: changes in antibiotic susceptibility, enzymatic activity, and antigenicity among colonial morphotypes.

Colonial variants of Pseudomonas aeruginosa have received renewed interest because of their occurrence in sputum cultures of patients with cystic fibrosis. We encountered 11 strains of P. aeruginosa from various body sites of non-cystic fibrosis patients. The strains showed two to three colonial variants, including smooth, rough, and iridescent morphotypes that arose from subculture of a single colony of P. aeruginosa originating from a primary source. The colonial segregants differed in antibiotic susceptibility (resistance to gentamicin, carbenicillin, chloramphenicol, and tetracycline), presence or absence of exoenzymes (gelatinase and elastase), degree of proteolytic activity (caseinase), pigmentation, and antigenicity. These observations suggest that in vivo dissociation with concomitant changes in enzymatic and surface properties might greatly enhance invasiveness. Concurrent differences in antimicrobial susceptibility among the colonial variants could account in some instances for the failure of antibiotic treatment in P. aeruginosa infections in which one would anticipate a positive therapeutic response.

Carbenicillin↗
PubMed1981

Pseudomonas aeruginosa enzyme profiling: predictor of potential invasiveness and use as an epidemiological tool.

The enzymatic potential of 54 clinical and 22 environmental isolates of Pseudomonas aeruginosa from soil and water were evaluated by substrate plate assays. Clinical isolates produced substantial levels of 9 of the 11 enzymes assayed, whereas strains recovered from soil or water were relatively inert enzymatically. Elastase, deoxyribonuclease, and elevated protease activities were associated preferentially with clinical isolates of systemic origin; these activities were found twice as frequently in clinical isolates as in strains derived from sputum or the urogenital tract. Our data suggest that these factors may play an important role in the dissemination of P. aeruginosa from local or superficial sites. A comparison of the enzyme profiles of the environmental and clinical isolates indicated that colonization or infection by environmental strains of P. aeruginosa is a rare event and that environmental and clinical strains comprise separate biovars. Epidemiologically, enzyme profiles permitted the fingerprinting and differentiation of clinical strains from various sources.

Humans↗