ABSTRACT
INTRODUCTION: Enterococci are recognized as opportunistic pathogens, as well as commensals in both humans and animals. They are an important cause of nosocomial infections, difficult to treat, as the organism have intrinsic and acquired resistance to many antibiotics. AIM: To isolate and identify clinically relevant Enterococcus up to species level from all the clinical samples processed in the microbiology laboratory and also to study their resistance pattern. MATERIALS AND METHODS: A prospective study was carried out for a period of one year from May 2014 to April 2015 at the Department of Microbiology, Subharti Medical College, Meerut, Uttar Pradesh, India. A total of 200 isolates of Enterococcus species from 15342 clinical samples obtained from IPD/OPD patients irrespective of age, having suspicion of bacterial infection were processed in the microbiology laboratory. Identification was done with standard biochemical methods. Antibiotic susceptibility testing was done on Muller Hilton agar plate by Kirby Bauer disc diffusion method. High-Level Gentamycin Resistance (HLGR) and High-Level Streptomycin Resistance (HLSR) were further confirmed by Agar dilution method and Broth microdilution method. Vancomycin and linezolid resistance was further confirmed by Agar dilution method and MIC was calculated by using VITEK 2, Biomerieux. All methodology was followed as per Clinical and Laboratory Standards Institute (CLSI) M100-S 24, 2014 guidelines. RESULTS: E. faecalis (n=169, 84.5%) was the predominant species isolated, followed by E. faecium (n=27, 13.5%) and E. casseliflavus (n=4, 2%). A total of 25 (12.5%) isolates were HLGR, 13 (6.5%) isolates were HLSR and 62 (31%) isolates were HLGR+HLSR. Vancomycin resistance was found in 14 (7%) isolates of which 11 (78.5%) were Van A and 3 (21.4%) were Van B, detected phenotypically as per relative MIC of vancomycin and teicoplanin. Linezolid resistance was seen in 4 (2%) of isolates which were vancomycin as well as high-level gentamycin and high-level streptomycin resistant. CONCLUSION: Isolation of Enterococcus species resistant to most of the higher antibiotics like vancomycin and linezolid, with high prevalence of High-Level Aminoglycoside Resistance (HLAR), from hospitalized patients is a major concern as such isolates have limited or no therapeutic option.
ABSTRACT
BACKGROUND AND OBJECTIVES: Biofilms are colonies of microbial cells encased in a self-produced organic polymeric matrix. The biofilm production is more important for nonalbicans Candida (NAC); as C. albicans possess many other mechanisms to establish infections. Correct identification of Candida species has gained importance due to persistent rise in infections caused by NAC. We sought to isolate, identify Candida species in clinical isolates and study biofilm formation. MATERIALS AND METHODS: Modified microtiter plate method was performed to study biofilm formation by isolates in Sabouraud's dextrose broth. It was then quantitatively assessed using a spectrophotometer. Biofilm formation was graded as negative, +1, +2, +3 and + 4 on the basis of percentage absorbance. RESULTS: Biofilm formation was observed in 16 of 40 (40.0%) isolates of C. albicans as compared to 39 of 78 (50.0%) of isolates of NAC. Strong (+4) biofilm production was seen in maximum biofilm producers in C. tropicalis (12 of 27) followed by C. albicans (8 of 16). Total biofilm producers were significantly more among high vaginal swab isolates 63.2% (12 of 19) and urine isolates 59.2% (29 of 49), when compared to blood isolates 34.2% (13 of 38) as well as other isolates 27.5% (11 of 40). INTERPRETATION AND CONCLUSIONS: NAC species are qualitatively and quantitatively superior biofilm producers than C. albicans. Biofilm production is the most important virulence factor of NAC species and compared to other lesions, it is more significantly associated with luminal infections.
