Are uropathogenic enterococci becoming smarter day by day? Changing trends of antimicrobial resistance and species distribution among uropathogenic Enterococcus species

Objectives: Urinary tract infections (UTI) are among the common infections in the community as well as in healthcare settings. The enterococci are most common among Gram-positive cocci (GPC) causing these infections. The change in the trends of species distribution of enterococci and their antimicrobial resistance frequently results in therapy failure. We planned this study to know the species distribution and antimicrobial resistance trends among enterococci isolated from patients presenting with UTIs. Material and Methods: The urine samples collected from the suspected cases of UTI were processed by culture on cystine lactose electrolyte-deficient agar. The species-level identification and antimicrobial susceptibility testing of isolated organisms after the preliminary identification was done on the VITEK-2 compact. Results: Out of a total 4961 urine specimens collected and processed, 1403 had significant growth on culture, consisting of Gram-negative (65%), Gram positive (18%), and Candida species (17%). Out of a total 257 isolates of GPC, 230 were enterococci comprising Enterococcus faecalis (48%), Enterococcus faecium (41%), Enterococcus gallinarum (8%), and Enterococcus casseliflavus (2%). The majority of the Enterococcus isolates were susceptible to glycopeptides and linezolid. Conclusion: Enterococci are common and important causes of UTI. The changing trends in the form of the emergence of other species including E. gallinarum and E. casseliflavus showing higher resistance against nitrofurantoin and other first-line drugs indicate the necessity of automated or molecular methods of identification before the institution of antimicrobial chemotherapy.