DNA AND PROTEIN FINGERPRINTING OF BACTERIOCIN PRODUCING ENTEROCOCCI OF CLINICAL ORIGIN

Abstract

Introduction: Enterococcus is one of the most common etiological agents of nosocomial infections with multiple clinical strains that produce bacteriocins. This study aims to explore the genomic and proteomic diversity of the bacteriocinogenic and non-bacteriocinogenic clinical Enterococci.
Methods: Stab overlay and cross streak methods were used to identify bacteriocin producing Enterococci. Bacteriocin producers and selected non-producers were taxonomically identified by 16S rDNA sequencing. Genomic variations of the isolates were explored by randomly amplified polymorphic DNA (RAPD-PCR), whereas sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) was employed to discern the proteomic diversity of the isolates.
Results: Out of 109 clinical isolates screened, 9 and 4 were respectively found to be bacteriocin producers and non-producers. Of 13 selected isolates, 8 were identified as Enterococcus faecalis and 3 were identified as Enterococcus faecium. Two isolates, SMN14 and SMN17, were failed to amplify by universal primers of 16S rDNA gene. RAPD analyses showed that out of 6 arbitrary primers, 3 were able to successfully resolve the genetic variations present amongst the isolates of Enterococcus faecalis or Enterococcus faecium. Consistently, SDS-PAGE of total bacterial lysate not only demonstrated the total protein expressional differences amongst the selected isolates but also distinguish bacteriocin producers from non-producers.
Conclusions: Our findings show that simple assays like SDS-PAGE and RAPD may not only augment taxonomic resolution of Enterococci but also points to their metabolic potential like bacteriocin production. Therefore, such approaches could further be exploited for epidemiological investigations of Enterococci and potentially other bacterial pathogens. Nevertheless, large scale studies are warranted in this regard.