Molecular detection of antimicrobial resistant genes (ermB, mef and tetM) in Streptococcus pneumoniae in Baghdad hospital

Abstract

In recent years antibiotic resistance among Streptococcus pneumoniae strains has caused significant health problems worldwide. Current study was under taken to determine the antibiotic resistance patterns and to explore the presence of three antimicrobial resistant genes (erythromycin ribosomal methylase B ermB, macrolide efflux mef(A/E), and tetracycline resistance determinant tetM) in clinical isolates at different hospital in Baghdad city. The research was carried out at the University of Baghdad’s Institute of Genetic Engineering and Biotechnology for Postgraduate Studies, as well as in the laboratories of Baghdad hospitals. Twenty-five isolates of S. pneumoniae were identified by using cultural, morphological and biochemical characteristics as well as the diagnosis by VITEK2 system. All isolates studied were subjected to antibiotic sensitivity testing using the disc diffusion method. By Kirby–Bauer test. Using 10 antibiotics represented by Amoxicillin, Azithromycin, Chloramphenicol, Clarithromycin, Clindamycin, Erythromycin, Imipenem/EDTA, Levofloxacin, Tetracycline and Vancomycin. The resistance percentage of the isolates were 28%, 28%, 24%, 80%, 80%, 80%, 0%, 0%, 64%, 72% respectively. Genomic DNA was extracted from S. pneumoniae isolates and was applied in a polymerase chain reaction (PCR) to amplify certain genes. The PCR results were: fifteen isolates (60%) show positive results for the presence of ermB gene and the amplicon size was 745bp. Six isolates (24%) show positive results for the presence of mef gene and the amplicon size was 315bp. Twelve isolates (48%) show positive results for the presence of tetM gene and the amplicon size was 406bp. As concluded from the present study, that the results exhibited that the presence of the antibiotic resistance pattern can be considered as a serious issue.