Characterization of Virulence Factors in Uropathogenic Escherchia Coli by Phenotypic and Genotypic Methods

Seetha, A (2014) Characterization of Virulence Factors in Uropathogenic Escherchia Coli by Phenotypic and Genotypic Methods. Masters thesis, Madurai Medical College, Madurai.


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INTRODUCTION: Urinary tract infection is one of most common Gram negative infections. Escherchia coli (E.coli) is the most common cause UTI both in community acquired(80%) as well as in nosocomial infection (35%). The uropathogenic E.coli posses certain virulence factors for the establishment of UTI. They are fimbrial and afimbrial adhesins, hemolysin, serum resistance, iron uptake system and biofilm production. Among the fimbrial adhesions, P fimbriae are most important in pathogenesis of UTI. MATERIALS AND METHODS: A total of 620 urine samples were collected from symptomatic UTI patients admitted to Government Rajaji Hospital, Madurai, attached to Madurai Medical College. Among those showing significant Bacteriuria of E.coli were processed for detection of virulence factors namely, mannose resistant hemagglutination, hemolysin, serum resistance, biofilm production and cell surface hydrophobicity by phenotypic methods. The various virulence genes coding fimbrial and afimbrial adhesins, hemolysin, such as namely, pap, hly, sfa and afa were detected by genotypic methods using PCR. Fecal isolates of E.coli from healthy volunteers were taken as control. Antibiotic susceptibility testing was also carried in UPEC isolates. RESULTS: Out of 620 urine samples proceeds, 463 samples showd bacteriuria with Gram staining. Out of 463 samples processed, 182 samples had shown significant growth of E.coli. These 182 samples after processing for virulence factors revealed MRHA in 37.91%, hemolysin in 36.81%, cell surface hydrophobicity in 44.51%, serum resistance in 25.27% and biofilm in 23.08% of the urinary iaolates of E.coli. Among fecal isolates of E.coli, 3.3%of MRHA, 2.75% of hemolysin, 11.54% of cell surface hydrophobicity, 6.04% serum resistance and 2.20% of biofilm production were detected. The virulence genes found were pap gene 34.07%, hly 40.11%, sfa 11.54% and afa 8.24%. Antibiotic susceptibility study revealed increased resistance to ampicillin, fluroquinolones, and cephaosporins. DISCUSSION & CONCLUSION: This study showed that depending upon the presence virulent factors we can manage UTI and prevent further complications. The virulence genes detection showed more percentage of pap gene. In future, the plan for vaccine production can be also based on these virulence factors. Changing antibiotic susceptibility in UPEC also helps cliniciansus to provide a antibiotic policy.

Item Type: Thesis (Masters)
Uncontrolled Keywords: UPEC, MRHA, Hemolysin, serum resistance, Biofilm, Cell surface Hydrophobicity, Drug resistance.
Subjects: MEDICAL > Microbiology
Depositing User: Subramani R
Date Deposited: 23 Mar 2020 16:40
Last Modified: 17 Aug 2020 09:16

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