ABSTRACT
Background: Several enterococcal species are increasingly being reported from clinical infections, besides the major species. Aim: This study was undertaken to determine the prevalence of unusual enterococcal species and their antimicrobial susceptibility patterns, virulence factors, and molecular characterization. Study Design and Settings: The study was conducted in Department of Microbiology and associated Tertiary Care University Hospital in North India. Materials and Methods: Enterococcal isolates were collected for a period of 2 years from clinical specimens. Identification and elaborate phenotypic characterization was done biochemically. All the isolates were tested by Kirby–Bauer disc diffusion method and breakpoint minimum inhibitory concentration for susceptibility against standard antibiotics. Screening for vancomycin‑resistant enterococci (VRE), high‑level aminoglycoside resistance was done on brain heart infusion agar incorporated with 6 μg/ml vancomycin, 500 μg/ml gentamicin, and 2000 μg/ml streptomycin, respectively. VRE isolates were tested for the presence of vanA, vanB, and vanC genes and high‑level gentamicin resistant (HLGR) isolates for aac‑6’‑aph‑2’ gene by polymerase chain reaction (PCR). Hemolysin and gelatinase production, hemagglutination and biofilm formation were detected along with asa1, gelE, esp, hyl, and cylA genes by multiplex PCR. Results: Of 403 enterococci, 93 (23.07%) isolates were identified as unusual species and atypical variants. Resistance of 52.68%, 46.23%, 44.08%, and 6.45% for ampicillin, ciprofloxacin, high strength gentamicin, and vancomycin, respectively were noted. Presence of vanC gene in Enterococcus gallinarum and Enterococcus casseliflavus isolates and vanA gene in Enterococcus durans and Enterococcus hirae and aac‑6’‑aph‑2’’ gene was found in 33.14% (14/41) of the HLGR isolates. The most frequent virulence factor was biofilm production. Only a few isolates harbored asa1 (2), gelE (9), and hyl (3) genes. Conclusion: Considerable prevalence of pathogenic unusual species of enterococci was seen along with their emerging drug resistance and virulence. Complete identification and routine speciation is essential to limit their emergence as major species in near future.
ABSTRACT
Tuberculosis is the most prevalent infection worldwide. The emergence of drug-resistant Mycobacterium tuberculosis [M. tuberculosis] isolates emphasizes that it is necessary to monitor drug resistance of the organism against anti-tubercular drugs. We analyzed 327 M. tuberculosis isolates from patients who were cared for at three different health care centers, herein after known as study areas [SAs], in North India. Of the 327 total M. tuberculosis isolates, 255 were from a tertiary health care center [Varanasi, Uttar Pradesh [SA-1]], 48 were from a District tuberculosis center [Sawai Madhopur, Rajasthan [SA-2]], and 24 were from a different District tuberculosis center [Buxar, Bihar [SA-3]]. Drug susceptibility testing against first-line antibiotics [viz. isoniazid, rifampicin, streptomycin, and ethambutol] was conducted for all the isolates using 1% proportional method. We found that the rates of acquired resistance were consistently higher than the rates of initial drug resistance. In new, untreated cases, a higher degree of MDR-TB was observed at SA-1 [13.3%] and SA-3 [25.0%], whereas it was observed in only 7.1% of the isolates at SA-2. In previously treated patients, MDR cases were found in 35.7% of the isolates from SA-1, 66.6% of the isolates from SA-2, and 43.8% of the isolates from SA-3. Resistance to a single drug was found at a much lower rate, ranging from 0.0 to 6.3% in new cases as well as previously treated cases. In conclusion, the primary resistance of M. tuberculosis is low, but acquired drug resistance is slightly higher in North India