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

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.

Monoclonal antibody affinity purification of a 78 kDa membrane protein of Leishmania donovani of Indian origin and its role in host-parasite interaction.

Monoclonal antibodies were raised against pathogenic promastigotes of Leishmania donovani of Indian origin. Among these, one was used for immuno-affinity purification of a 78 kDa membrane protein present in both the amastigote and promastigote forms of the parasite. Results of immunoblot experiments with the anti-78 kDa antibody revealed that the protein was present only in parasites belonging to the L. donovani complex. The expression of the protein was observed to be the same during different phases of growth of the promastigotes. Therefore, the 78 kDa protein is neither stage-specific nor differentially regulated. Surface iodination and subcellular fractionation of the promastigotes indicated that the protein was localized on the cell surface. The 78 kDa protein was found to inhibit the binding of promastigotes to macrophages significantly, suggesting that it may play a role in the process of infection. Thus, here we report the purification of a surface protein of L. donovani of Indian origin, which may play an important role in the process of infection.

Studies on stibanate unresponsive isolates of Leishmania donovani.

Visceral leishmaniasis, also known as kala-azar (KA) is generally caused by Leishmania donovani. Organic pentavalent antimonials (SbV) is the first line of treatment for KA. However, the number of KA patients unresponsive to treatment with Sb(V) is steadily increasing in India and elsewhere. The primary objective of this work is to determine the factor(s) associated with the rise of unresponsiveness. Analysis of the clonal population of parasites clearly indicated that wild type parasites isolated from KA patients who were clinically cured after treatment with Sb(V), were a mixture of resistant and sensitive cells. The resistant promastigotes were also resistant as amastigotes in vivo. It was further observed that Stibanate sensitive parasites can be made resistant to the drug by repeated passages in experimental animals followed by incomplete treatment with suboptimal doses of the drug. These results suggest that the steady rise in Sb(V) unresponsiveness of KA patients in India is due to infection with resistant parasites, generated as a result of irregular and often incomplete treatment of the patients