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|Title:||Profiling of some virulence genes of Escherichia coli obtained from faeces from some wild captive animals|
|Publisher:||Rajasthan University of Veterinary and Animal Sciences Bikaner-334001|
|Abstract:||Animals kept at zoo are usually bred in captivity and have been reported to be associated with bacterial infections of which Escherichia coli is an important pathogen. Most E. coli strains are harmless, but some pathogenic strain can cause bloody diarrhea, anemia, stomach cramps gastroenteritis, urinary tract infections, dysentery, hemorrhagic uremia, syndrome, bladder, kidney infections and extra intestinal infections, septicaemia, pneumonia and meningitis in humans and animals. Pathogenic strains of E. coli produce important virulence factors like enterotoxins, siderophores, shiga like toxins (verotoxin), cytotoxic necrotizing factors and haemolysin. Besides these other factors responsible for infection are adhesins and invasins. The literature regarding studies on E. coli from wild life is scarce. Hence, Escherichia coli was selected as the target organism for this study. In the present investigation isolation and identification of Escherichia coli from faeces from wild captive species was carried out by conventional methods, phenotypic characterization viz cultural and biochemical properties of E. coli along with antibiogram was done. The isolates identified on biochemical base were further confirmed by PCR based on 16S rRNA ribotyping and these isolates were then subjected to profiling of eaeA , hlyA, stx1, stx2, and pap C PCR methods. Of the 140 faecal collected from wild captive animals in different cities (Bikaner, Jodhpur and Udaipur), Rajasthan, 129 isolates were tentatively identified as E. coli on the basis of cultural and biochemical properties. These 129 isolates were further subjected to polymerase chain reaction for 16 S rRNA ribotyping using species specific primers where 110 (61 from Bikaner Zoo, 14 from Umed garden, Jodhpur and 35 from Sajjan Niwas and Gulab bagh, Udaipur) isolates produced species specific amplicons of 662 bp confirming them to be E. coli. Hence the recovery of Escherichia coli was 78.57 per cent. The overall analysis of antibiograms for all the isolates from all three localities i.e. Bikaner, Jodhpur and Udaipur revealed that the most effective antibiotic was Co-Trimoxazole (93.05%) against which most of the isolates were sensitive followed by Norfloxacin against which 90.99% of the isolates were sensitive, 88.37% isolates was sensitive to Gentamicin, 87.87% isolates was sensitive to Polymyxin-B, 76.37% isolates was sensitive to Chloramphenicol, 73.11% isolates was sensitive to Azithromicin and 72.83% isolates was sensitive to Doxycycline hydrochloride. Piperacillin showed resistance to 82.12% isolates. Shannon-wiener index of all the resistotypes of E.coli was observed to be 0.42, showing very low diversity quantitatively. A variable percentage of virulence genes namely eaeA, hlyA, papC, Stx1 and Stx2 was detected in different wild captive animals from three different localities but STa, STb and LT genes were not detected in any of the isolates. The overall prevalence of eaeA, hlyA, papC, Stx1 and Stx2 genes detected were 55.71%., 50.45%, 64.02%, 34.13% and 30.30%, respectively. In order to find out the diversity of E. coli in relation to virulence genes Shannon-wiener index was calculated. The overall Shannon-Wiener index was observed to be 2.15 showing considerable diversity of the virulence genes (eaeA, hlyA, papC, stx1 and stx2) of all the E. coli isolates from three locations. The observed high diversity of patterns of virulence genes in the E. coli is suggestive of association of these genes with the chromosomal DNA, which is relatively less prone to changes by mechanisms of horizontal gene transfers than plasmid-borne or phage encoded genetic elements.|
|Theme:||Profiling of some virulence genes of Escherichia coli obtained from faeces from some wild captive animals|
|Appears in Collections:||Thesis|
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