revalence of Tetracycline Resistant Genes in Staphylococcus aureus Isolates from Surgical Site Infections Egypt

Abstract

The aim of the present study was to investigate the prevalence of tetracycline resistance genes among isolated S. aureus from healthcare associated surgical site infections. The present study included 350 clinical samples from healthcare associated surgical site infections. Identified S. aureus strains were subjected to antimicrobial susceptibility testing, detection of methicillin resistance by cefoxitin disc and molecular study of mecA and tet genes that were carried out by polymerase chain reaction and multiplex polymerase chain reaction, respectively. There were high resistance rates of isolated S. aureus to gentamicin (71.2%), kanamycin (66.5%) and ceftazidime (41.8%). Resistances to tetracycline, doxycycline and minocycline were 60.6%, 56.5% and 45.3%, respectively. In the comparison between MRSA and MSSA as regards antibiotics resistance, there was a significant increase in resistance to tetracycline, doxycycline, minocycline (P=0.0001) and erythromycin (P=0.01) among MRSA strains compared to MSSA. The tetracycline resistant genes detected were tetK (92.3%) and tetM (25.2%). Combined genes were detected in 22.3% of S. aureus. None of tetracycline isolates had tetL or tetO gene. There was significant higher frequency of telK, tetM and combined genes among MRSA compared to MSSA (P=0.0001). The present study highlights the prevalence of multiple antibiotics resistance among clinical isolates of S. aureus associated with healthcare associated infections. The resistance increases among methicillin resistant S. aureus. The resistance to tetracycline, minocycline and doxycycline were common. The common genetic basis of the resistance to tetracycline was the tetK and tetM genes.