Evaluation of antimicrobial susceptibility among Enterococcus species by E-test method at Khatam-ol-Anbia hospital during 2013-2014

Abstract

Background: Over the past decade, Enterococci have been shown to be an important cause of nosocomial and community-acquired infections. Inappropriate use of antibiotics led to changes in the pattern of antibiotic resistances in Enterococcus species. Unfortunately, no study has been performed in Iran in recent years regarding the antimicrobial resistance of Enterococci using the E-test method as a base. We must gain sufficient knowledge about the regional antibiotic resistances related to Enterococcus so that we can monitor the prevalence and antimicrobial resistance of Enterococcus by administering appropriate treatments. Objectives: The objective of this study was to evaluate the antimicrobial susceptibility among Enterococcus species by the E-test method at Khatam-ol-Anbia hospital during 2013 - 2014. Patients and Methods: This descriptive cross-sectional study was carried out during 2013 - 2014. All clinical samples were collected from the intensive care unit (ICU) and general wards of Khatam-ol-Anbia hospital. All Enterococcus species were detected via biochemical testing. Antimicrobial susceptibility and minimum inhibitory concentration (MIC) were determined via disk diffusion and the E-test method. We used descriptive statistics to analyze the data. Results: A total of 53 Enterococci were isolated from clinical samples of blood, urine, wounds, sputum, and cerebrospinal fluid (CSF) over a two-year period from the ICU and general wards. The isolated Enterococcus species were 77.35% E. faecalis, 18.86% E. faecium, and 3.77% other species. Species evaluated by E-test were resistant to imipenem, ampicillin, co-trimoxazole, gentamicin, rifampicin, vancomycin, linezolid, and teicoplanin; 54%, 68%, 100%, 93.8%, 60.4%, 39.6%, 0%, and 29.2%, respectively. Among the strains of enterococci, 90.9% of E. faecium and 20% of E. faecalis species were resistant to vancomycin. Conclusions: According to these findings, antibiotic-resistance patterns have changed, and vancomycin resistance, especially among E. faecium, is rising because of nosocomial infections. Consequently, it has become a serious subject for patients admitted into a hospital.