Verotoxic Escherichia coli (STEC) from beef and its products.

In the present investigation, out of 27 (24.10%) strains of Escherichia coli isolated from 112 beef samples comprising raw meat (45), kabab (36) and kofta (31), 9 (33.33%) belonging to 7 different serotypes were verotoxic as tested by vero cell cytotoxic assay. Serotype O145 was the predominant STEC in raw meat. Interestingly, one STEC-O157 strain was also detected. All the STEC strains were positive for Stx genes by polymerase chain reaction showing stx2 (77.78%) to be most predominant followed by stx1 (22.22%). Phenotypic enterohaemolysin production on washed sheep blood agar supplemented with CaCl2 revealed 6 (66.67%) STEC strains to be positive. Presence of STEC in cooked beef products, viz., kabab and kofta appeared to be a matter of concern and potential threat to public health.

Effect of growth medium on hydrophobicity of Staphylococcus epidermidis.

The present study was undertaken to evaluate the effect of growth medium on expression of hydrophobicity of Staphylococcus epidermidis. A total of 24 hydrophobic isolates of S. epidermidis, determined by n-hexadecane adherence assay (HAA) earlier were included. Five different growth media: horse blood agar (HBA), brain heart infusion agar (BHIA), brain heart infusion broth (BHIB), tryptic soy broth (TSB) and proteose peptone broth (PPB) were used. All 24 isolates exhibited the reproducible hydrophobicity when grown on HBA; however, 20 (83.33%), 19 (79.16%), 15 (62.50%) and 13 (54.16%) isolates were found to be hydrophobic when grown in BHIA, BHIB, TSB and PPB, respectively. HBA was found to be the most suitable medium for detection of hydrophobicity of S. epidermidis followed by BHIA or BHIB.

Comparative evaluation of hydrophobicity measures for virulence determination of Staphylococcus epidermidis from hospitalized patients & healthy individuals.

BACKGROUND & OBJECTIVES: Hydrophobicity is one of the recognized markers for identifying pathogenic strains of Staphylococcus epidermidis. A number of tests are available for measuring the hydrophobic character but three tests viz., salt aggregation test (SAT), n-hexadecane adherence assay (HAA) and xylene adherence assay (XAA) are in common practice with different degrees of sensitivity. However, in the Indian context, no systematic study has been reported on the hydrophobicity of S. epidermidis. Hence, the present study was undertaken to compare the three methods for hydrophobicity measurement for identifying the pathogenic isolates of S. epidermidis. METHODS: Of the 597 samples obtained from milker's and butcher's (hand and nose), hospitalized pre-operative patients (hand, nose, ear), and post-operative patients (blood) examined, 212 isolates of S. epidermidis were recovered using established laboratory procedures. The isolates were screened by the three tests viz., SAT, HAA and XAA. The identified hydrophobic isolates were further tested by mouse inoculation method. RESULTS: Of the 212 S. epidermidis isolates studied, 24 (11.32%), 23 (10.84%) and 4 (1.88%) were found to be hydrophobic as detected by HAA, XAA and SAT, respectively. No isolates from apparently healthy individuals were found to be hydrophobic by SAT while 13 (8.76%) and 10 (8.24%) strains from apparently healthy individuals were detected to be hydrophobic by HAA and XAA, respectively. Seven (33.38%) isolates each were hydrophobic by HAA and XAA and 4 (22.22%) by SAT among the isolates from hospitalized post-operative patients. INTERPRETATION & CONCLUSION: The results suggested that there was no difference in the number of strains detected as hydrophobic by HAA and XAA, and any of the two tests may be used for screening the hydrophobic strains of S. epidermidis from healthy individuals and patients.

Zoonoses and bats: a look from human health viewpoint.

Bats are the most abundant and most widely distributed mammals on the Earth after humans. Except Antarctica and some small remote islands, they are prevalent worldwide. Although the actual role played by bats as reservoir or in disseminating zoonoses is still enigmatic a multitude of zoonotic diseases are known to be associated with bats. Such diseases including viral, bacterial, parasitic, fungal and rickettsial diseases, reported from all over the world including India have been briefed in this article as an informative approach because dramatically increased and diversified human activities during the last few decades perturbing natural ecosystems are enough to compel public health personnel to have an investigative look at these flying mammals.

Isolation of verotoxin producing Escherichia coli from diarrhoeal and urinary tract infection patients.

Fourty nine Escherichia coli strains, isolated from diarrhoeal and urinary tract infection (UTI) patients, attending Bareilly district hospital, Uttar Pradesh during October to December, 1998 were screened for verotoxin (VT) production by Vero cell assay. Five strains produced characteristic cytopathic effect on Vero cell line, of which 4 were from diarrhoeal and one was from UTI-patient. The level of VT-production varied widely. Antibiotic sensitivity tests revealed that the VT-producing E. coli (VTEC) were mostly sensitive to kanamycin, norfloxacin and nalidixic acid but resistant to ampicillin and tetracycline.

Virulence factors of aeromonads--an emerging food borne pathogen problem.

Aeromonas spp. possess a number of virulence properties which are considered responsible for intestinal and extra-intestinal infections in human beings and also for a wide variety of infections in animals. The paper discusses current status of colonization and toxic factors of Aeromonas spp., especially in relation to food and biochemical markers. Future research needs are also identified.

Enterotoxigenic Escherichia coli from an outbreak with cholerigenic syndromes of gastroenteritis.

In an outbreak of food-poisoning, 76 out of 200 students who had dined in an Institute mess experienced acute cholerigenic syndromes of gastroenteritis. Processing of the seven stool samples of affected students and remnants of 4 out of 5 type of food for isolation of bacterial pathogen(s) revealed only the presence of Escherichia coli which were serotyped as 020, 026, 045, 053 and one untypable (UT). Enterotoxigenicity testing of these isolates revealed serotypes 020, 026 of E. coli to be heat-labile enterotoxin producer when subjected to Biken test, Latex agglutination test and co-agglutination test. Based on the laboratory findings there are good reasons to believe that serotype 020 was responsible for this episode.