High-level resistance to aminoglycosides and ampicillin among clinical isolates of Enterococcus species in an Iranian referral hospital

  • Seyed Hossein Mousavi Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
  • Hadi Peeri-Doghaheh Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
  • Behnam Mohammadi-Ghalehbin Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
  • Roghayeh Teimourpour Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
  • Dadras Maleki Microbiology Laboratory, Imam Hospital, Ardabil University of Medical Sciences, Ardabil, Iran
  • Farzad Khademi Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
  • Mohsen Arzanlou Department of Microbiology, School of Medicine, Ardabil University of Medical Sciences, Ardabil, Iran
Keywords:
Enterococcus faecalis;, Enterococcus faecium;, High-level resistance;, Gentamicin;, Streptomycin;, Ampicillin

Abstract

Background and Objectives: Nowadays, high-level aminoglycosides and ampicillin resistant Enterococcus species are among the most common causes of nosocomial infections. The present study was conducted to determine the prevalence of high-level resistance to aminoglycosides and ampicillin among clinical isolates of Enterococcus species in Ardabil, Iran.
Materials and Methods: In this cross–sectional study, a total of 111 Enterococcus species were collected from different clinical specimens between 2013 and 2015. Enterococcus species were identified using standard phenotypic and genotypic methods. BHI agar screen and agar dilution methods were used for detection of high-level gentamicin and streptomycin resistance (HLGR and HLSR) and minimal inhibitory concentration (MIC) of ampicillin, respectively.
Results: Of 111 clinical isolates, 59 (53.2%) and 25 (22.5%) isolates were E. faecalis and E. faecium, respectively, based on the PCR results. Totally, 60.3% and 56.7% of isolates were HLGR and HLSR, respectively, as well as 51.35% were HLGR plus HLSR. Among HLGR isolates, 36 (61.01%), 18 (72%) and 13 (48.14%) were E. faecium, E. faecalis and non-faecalis non-faecium species, respectively. Among HLSR isolates, 33 (55.93%), 16 (64%) and 14 (51.85%) were E. faecalis, E. faecium and non-faecalis non-faecium species, respectively. All HLGR isolates contained aac(6´)Ie-aph(2″)Ia gene. Overall, the prevalence of high-level ampicillin resistance among Enterococcus species was 17.1%. For E. faecalis, E. faecium and non-faecalis non-faecium species, ampicillin resistance rates were as follows: 11 (40.74%), 7 (28%) and 1 (1.69%), respectively. For aminoglycoside antibiotics, the resistance rate was significantly higher in E. faecium isolates and for ampicillin it was higher in E. faecalis isolates.
Conclusion: The frequency of high-level aminoglycoside resistant enterococcal isolates in our hospital was high and significant ampicillin resistance was noticed. This would require routine testing of enterococcal isolates for HLAR and ampicillin susceptibility.

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Published
2020-07-31
How to Cite
1.
Mousavi SH, Peeri-Doghaheh H, Mohammadi-Ghalehbin B, Teimourpour R, Maleki D, Khademi F, Arzanlou M. High-level resistance to aminoglycosides and ampicillin among clinical isolates of Enterococcus species in an Iranian referral hospital. Iran J Microbiol. 12(4):319-324.
Section
Original Article(s)