Isolation, Identification and Speciation of Enterococci by Conventional Method and their Antibiogram

Abstract

Introduction: Enterococci are normal commensals in the gastrointestinal tract, oral cavity, vagina etc. They are organisms of low virulence, but are known to cause various clinical infections. Enterococcus is considered as an important nososcomial pathogen because of its intrinsic as well as acquired antibiotic resistance. The increasing importance of Enterococcus is largely due to their resistance to many antimicrobials particularly intrinsically resistant Enterococci, which is the cause of changing pattern of Enterococcal infection resulting in treatment failures. Objectives: 1. Isolation, Identification and speciation of Enterococci from clinical specimens by conventional method. 2. Determination of Antibiogram of such isolates of Enterococci. Materials and Methods: Over a period of one year, 3,197 various clinical specimens were processed and a total of 80 strains of Enterococci isolated. Such isolates were identified and speciated by recommended conventional tests and biochemical reactions. Their antibiotic susceptibility pattern was also determined to the common antibiotics by disc diffusion method as per the recommendations. Results: Among the total 80 strains of Enterococci, 69 were E.faecalis, 10 were faecium and one was durans and all the isolated strains were identifiable to the species level by conventional method. Maximum numbers of isolates were from urine specimen (38, 1.97%), followed by exudates (32, 5.54%) and blood (10, 1.40%), and with an overall incidence of isolation of Enterococci from the above said specimens is 2.5%. Among 80 strains of Enterococci 35% were β hemolytic & 63.75% isolates were non hemolytic. More than 50% of the total isolates were resistant to Ampicillin (E.faecalis – 49.27%, E.faecium -90%),Penicillin(E.faecalis–49.27%, E.faecium -80%),Tetracycline(E.faecalis–57.97%, E.faecium -70%), Erythromycin(E.faecalis –53.62% , E.faecium -60%) and Gentamicin (E.faecalis –59.42% E.faecium -80%) and the most useful antibiotic was ciprofloxacin to which 61.25% (E.faecalis – 62.31%, E.faecium -50% ) of the total isolates were sensitive. Conclusion: From this study it was possible to identify all the isolates of Enterococci to the species level by following conventional methods. It was observed in our study that there is more drug resistance to the tested antimicrobials among E.faecalis isolates.

Keywords

• e.faecalis
• e.faecium
• e.durans
• haemolysis
• antibiogram