Clinical Screening for Bacteriocinogenic Enterococcus faecalis Isolated from Intensive Care Unit Inpatient in Egypt

Abstract

A bacterium originally isolated from stool sample from ICU inpatient was biochemically and molecularly characterized and identified as Enterococcus faecalis OS6. This strain showed the ability to exert antimicrobial activities against some members of Gram-positive bacteria as Lactobacilli and Enterococci. However, no activities were detected against all tested Gram-negative and fungal indicator strains. Diminishing of antimicrobial activities upon heat and proteinase K treatments confirmed the proteinaceous nature of the recorded activity. Therefore, strain OS6 was extensively screened for the presence of 10 common bacteriocin structural genes where genes of Enterolysin A and Cytolysin were detected and confirmed by further gene sequencing. Further characterization of strain OS6 showed several virulence determinants including gelatinase, haemolysin, bile salt hydrolase and multiple antibiotic resistance traits towards 17 out of 31 different antibiotics. Most of these 17 antibiotics belonged to Cephalosporins, Aminoglycosides, Lincomycins, Polypeptides, Quinolones, Rifamycins and Sulfonamides classes. To the best of our knowledge, this is the first attempt to report production of bacteriocins (mainly Enterolysin A) in between pathogenic E. faecalis isolated from human clinical specimen in Egypt.