Identification of aminoglycoside resistance genes by Triplex PCR in Enterococcus spp. isolated from ICUs.
Early detection of antibiotic-resistant enterococci is an important part of patient treatment. Therefore, the aim of the present study was to evaluate the resistance patterns and simultaneously identify and characterise the resistance genes in Enterococcus spp. using a triplex polymerase chain reaction (PCR) method. In all, 150 consecutive Enterococcus spp were collected from several hospitals in Tehran (Iran) from January to December 2015. The Enterococcus species were identified by standard phenotypic/biochemical tests and PCR. The antimicrobial resistance patterns were determined using a disk diffusion method. The triplex PCR method was designed to identify gentamicin and other aminoglycoside resistance genes. Among the 150 Enterococcus specimens, 87 cases (58%) were Enterococcus faecalis, and 63 cases (42%) were Enterococcus faecium. The highest frequency of resistance was observed for tetracycline while the lowest was found for vancomycin. Among the identified samples, 56.9% contained the aac(6')-Ie-aph(2'')-Ia gene, 22.2% contained the aph(3')-IIIa gene, and 38.8% contained the ant(4')-?a gene. Eight percent of the isolates contained the three aminoglycoside resistance genes. Data analysis showed that there was a significant correlation between the phenotypic gentamicin resistance and the presence of the aminoglycoside resistance genes (18.9%, p <0.05), while the correlation between the phenotypic streptomycin resistance and the corresponding genes was not significant (2.8%, p ≥0.5). Nearly half of the identified Enterococcus strains had increased aminoglycoside resistance. The direct correlation between resistance genes, such as the aminoglycoside resistance factor, and phenotypic resistance was not significant (p > 0.05).
Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.
Reza
R
Mirnejad
Department of Microbiology, Science and Research Islamic Azad University, Damghan Branch, Damghan, Iran.
Nikta
N
Sajjadi
Department of Microbiology, Islamic Azad University Varamin-Pishva Branch, Tehran, Iran.
Sara
S
Masoumi Zavaryani
Department of Microbiology, Biology Faculty, Tonekabon Branch, Islamic Azad University, Tonekabon, Iran.
Vahhab
V
Piranfar
Department of Microbiology, Science and Research Islamic Azad University, Damghan Branch, Damghan, Iran.
Maryam
M
Hajihosseini
Department of Microbiology, Science and Research Islamic Azad University, Damghan Branch, Damghan, Iran.
Maliheh
M
Roshanfekr
D000123:Acetyltransferases / Q000235:genetics; D000617:Aminoglycosides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D004251:DNA Transposable Elements / Q000235:genetics; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D013293:Enterococcus faecalis / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D005798:Genes, Bacterial; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D007362:Intensive Care Units; D007492:Iran / Q000453:epidemiology; D060885:Multiplex Polymerase Chain Reaction; D009713:Nucleotidyltransferases / Q000235:genetics; D010770:Phosphotransferases / Q000235:genetics
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D000123:Acetyltransferases; D010770:Phosphotransferases; D009713:Nucleotidyltransferases