Clinico-microbiological Profile of Urinary Tract Infection with Special Reference to Uropathogenic E coli : Antibiotic susceptibility Pattern, Phylogenetic Background and Virulent Factor Distribution from West Bengal, India

ABSTRACT

Background and Objectives: Routine surveillance and monitoring studies pose a constant need to update clinicians on prevalent pathogens and rational and empirical treatment in Urinary Tract Infection (UTI). Escherichia coli (E coli) is the most commonly isolated uropathogen globally. Extended-Spectrum ?-Lactamase (ESBL) production and ?-Lactamase Inhibitor Resistance (BLIR) among these pathogens together with their uro-virulence determinants further complicate treatment approaches. This study investigated the clinico-microbiological pattern of UTI and determined the antibiotic sensitivity pattern, the phylogenetic background, and virulence determinants of E coli, the most commonly isolated uropathogen. Methods: Uropathogens isolated by urine culture from community and hospitalized patients were biochemically speciated. Antibiotic susceptibility was tested by Kirby-bauer disk diffusion method. Phylogenetic background and virulence determinants of E coli isolates were identified by PCR. SPSS 16.0 was used for statistical interpretation. Results: 45% of the urine samples showed growth positivity. 44% amongst them were E coli. All isolates were multidrug-resistant. 50% and 40% were ESBL producers and BLIR respectively. Former showed highest resistance to quinolone, fluoroquinolones, cotrimoxazole, and latter were resistant against all drugs tested except nitrofurantoin. Significant correlation existed between the ?-lactams, quinolone, fluoroquinolones, cotrimoxazole (p<0.05) resistance pattern. BLIR and ESBL E coli recorded highest prevalence of pathogenic phylogroup B2 and D respectively. Varied prevalence of fimbrial (fimH, papC, papEF, papG, GII) and toxin genes (iroN, hlyA, cnfI, i ucD, cdtBU) in ESBL, BLIR and non-ESBL isolates were observed. Their distribution was statistically significant (p=0.05). Interpretation and Conclusions: Nitrofurantoin is the drug of choice in empirical treatment of uncomplicated UTI. Aggressive and consistent investigation and health education are highly recommended for effective clinical management in UTI.