Clinical and molecular epidemiology of vancomycin-resistant Enterococcus faecium bacteremia from an Indian tertiary hospital.

We determined the clinical and molecular epidemiology of emerging nosocomial vancomycin-resistant Enterococcus faecium (VREfm)-causing serious bloodstream infections (BSIs) and the correlations between antibiotic resistance and virulence determinants among isolates. All isolates were confirmed by molecular methods (16SrRNA and E. faecium ddl genes) and tested for disk diffusion. PCR was used to detect aac(6')-aph(2″), vanA and vanB resistance genes, and asa1, cylA, ace, esp, gelE and hyl virulence genes. VREfm and high-level gentamicin-resistant (HLGR) representative isolates were selected to characterize by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Of 173 isolates, 73 (42.2%), 146 (84.4%), and 0 (0.0%) were vanA-containing VREfm, aac(6')-aph(2″)-positive HLGR, and vanB-positive. Independent predictors of VREfm infection were hematological malignancies (P = 0.001) and previous hospitalizations (P = 0.007). Observed mortality rate was 34.7%. Independent predictors of BSI-related mortality were endotracheal intubations (P < 0.001), gastrointestinal diseases (P = 0.002), and pulmonary disease (P < 0.001). All VREfm were resistant to vancomycin, teicoplanin, ciprofloxacin, and erythromycin. The esp, hyl, ace, asa1, cylA, and gelE genes were detected at 55.9, 22.5, 2.9, 2.3, 1.7, and 1.2%, respectively. The esp gene was significantly associated with VREfm compared to VSEfm (P = 0.001). PFGE analysis revealed 23 clones, with 7 major clones. The MLST analysis revealed the following five sequence types: ST80, ST17, ST117, ST132, and ST280, all belonging to CC17. The emergence and expansion of VREfm CC17 with limited antibiotic options in our hospital present a serious public health menace and represent challenges to infection control.

Emergence of high-risk multidrug-resistant Enterococcus faecalis CC2 (ST181) and CC87 (ST28) causing healthcare-associated infections in India.

High-risk hospital-associated multidrug-resistant (MDR) Enterococcus faecalis clonal complexes (CCs) such as CC2 and CC87 are enriched with virulence determinants that help to accumulate, colonize, and cause serious nosocomial infections. The aim of this study was to establish the epidemiology and clonal composition of 134 clinical E. faecalis isolates and to link molecular typing data with antimicrobial resistance and virulence determinants. All isolates were identified by conventional methods and confirmed by polymerase chain reaction (PCR) (16srRNA gene and ddl genes of E. faecalis/ E. faecium) in 5-years. Disc diffusion test was performed on all strains. We screened all E. faecalis for aac(6')-aph(2″), vanA, and vanB resistance genes, and aggregation substance-asa1, cytolysin-cylA, collagen-binding protein-ace, enterococcal surface protein-esp, gelatinase-gelE, and hyaluronidase-hyl virulence genes by PCR. Representative isolates of E. faecalis were characterized by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Out of 539 patients with enterococcal infections, 134 (24.9%) had E. faecalis infections, 366 (67.9%) had E. faecium infections, and 39 (7.2%) had infections due to other enterococcal species. Of the 134 isolates, 79.1% and 61.9% isolates were high-level gentamicin resistant (HLGR) and MDR. In multivariate analysis, independent predictor for infection due to MDR E. faecalis strains was a surgical intervention (OR 2.41, 95% CI 1.17-4.96, P = 0·017). Overall, the observed rate of in-hospital mortality was 11.9%. The gelE, asa1, ace, cylA, esp and hyl genes were detected in 87.3%, 78.4%, 54.5%, 53.7%, 36.6% and 3.0%, respectively in E. faecalis isolates. The asaI, cylA, and gelE genes were significantly correlated with MDR E. faecalis. The PFGE analysis showed 28 clones with four major clones. MLST analysis revealed two sequence types-ST28 (CC87) and ST181 (CC2). This is the first Indian report on the emergence of the high-risk hospital-associated worldwide-disseminated ST28 (CC87) and ST181 (CC2), which have enriched with multiple virulence determinants and resistance to antibiotics, paticularly ampicillin. This report indicates serious health concern and calls for on-going surveillance, close monitoring, and improved infection control procedures to stop further spread of these isolates.