Molecular Identification of Pathogenic Enterococci and Evaluation of Multi-drug Resistance in Enterococcus Species Isolated From Clinical samples of Some Hospitals in Tehran, Iran

Multidrug-resistant (MDR) enterococci cause many problems for physicians and infection control specialists in the recent years. Hence, by the identification of antibiotic resistance patterns of enterococci in different geographical regions an appropriate strategy can be developed to prevent bacterial antibiotic resistance and provide effective treatment. The current study aimed at identifying enterococci via molecular methods and evaluating multi-drug resistance patterns in Enterococcus species isolated from nosocomial samples of some hospitals in Tehran, Iran.

The current study was conducted on 300 nosocomial samples from different hospitals in Tehran, Iran. The identified Enterococcus species of E. faecalis and E. faecium were isolated via biochemical testing and confirmed using polymerase chain reaction (PCR). The antibiotic resistance pattern was determined using the disc diffusion method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines.

The highest antibiotic resistance was observed against quinupristin-dalfopristin, tetracycline, and erythromycin. Minimum inhibitory concentration (MIC) of vancomycin against the isolated antibiotic resistant Enterococcus spp. was ≥256 µg/mL. According to the results of the current study, 69.6% of E. faecalis and 80% of E. faecium isolations showed multi-drug resistance.

Increase of antibiotic resistant bacteria, especially MDR species, is a severe health threatening problem worldwide. The increase of MDR bacteria limited therapeutic solutions to the patients with enterococcal infection, increased treatment costs, and led to transmission of resistant genes among bacteria. It is highly important to find antibiotic resistant patterns to compile guidelines for infectious diseases.