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Abstract Summary Enterococci are common inhabitants of the GI tract of humans. Enterococci have emerged as one of the leading cause of nosocomial infections, and recently have been persisting clinical problem globally due to their resistance to antibiotics. Also, it was likely that other virulence determinants were involved in the success of these microorganisms in the hospital setting. Isolates were diagnosed by culture and biochemical reactions. The antibiotic sensitivity pattern was determined by Kirby-Bauer disc diffusion method. Vancomycin resistance was detected phenotypically by agar screen method and genotypically by detection of vanA/B. The production of cytolysin, gelatinase and biofilm were detected phenotypically and genotypically by PCR of (cylA, gelE, esp and vanA/B genes). We undertook this study to determine the prevalence of enterococci causing nosocomial infections, intestinal carriage and environmental contamination in the ICUs of Assiut University Hospitals. Also, to determine some virulence factors and the antibiotic resistance of enterococci isolates. In this study, 30 clinical isolates, 10 environmental and 10 commensal isolates were included. Considerable percentage of enterococci was recorded in nosocomial infections in the ICUs of Assiut University Hospitals (10.5%). The highest percentages of contamination by enterococci were recorded in the chest ICU (56%). Also, the highest percentage of enterococci was recorded in the lower respiratory tract infections samples (86.7%). The most prevalent species of enterococci were E.casseliflavus (36%), E.gallinarum (32%) and E.faecalis (30%). High prevalence of vancomycin resistance was detected, in commensal isolates (70%), for environmental (50%) and clinical isolates (40%). Also, it was found that artificial feeding and immunodeficiency were the important risk factors for vancomycin resistance. Phenotypic detection of virulence factors revealed that 12% of the isolates were β haemolytic, 48% of the isolates were positive for gelatin hydrolysis. Summary 91 Different results were reported in biofilm detection by three methods; however the microtiter plate method showed the highest percentage of detection of biofilm among all isolated species. Regarding the antibiotics resistance, enterococci were completely resistant to most antibiotics tested. Also, various percentages of resistance were reported for amoxicillin & clavulanic acid (95%), cefazolin (98%), norfloxacin (96%), lomefloxacin (98%), gentamicin (98%), oxytetracycline (64%), tiecoplanin (40%), tetracycline (58%) and chloramephincol (56%). The least resistance was reported for linezolid (2%). The best method for detection of vancomycin resistance was agar screening method. For genotypic detection of virulence genes, 62% for gelE gene, 12% for esp gene, 12% for vanB gene and 2% for vanA gene. cylA gene was absent from all isolates. Positive correlation between genotypic and phenotypic method for detection of gelatinase and biofilm (P=0.001, 0.044 respectively). In addition, significant correlation was recorded between antibiotic resistance biofilm formations. For vancomycin resistance by agar screening method, strong correlation with detection of vanB gene was reported (P=0.006). We conclude that enterococci especially vancomycin resistant caused a significant percentage of health care acquired infections, intestinal carriage and environmental contamination in the ICUs of Assiut University Hospitals. Isolates were highly resistant to most antimicrobials. A considerable percentage produced cytolysin, gelatinase and biofilm. |