Isolation, Molecular Identification, and Antimicrobial Susceptibility Testing of Staphylococcus aureus Isolates

Abstract

Staphylococcus aureus is a gram-positive pathogenic bacterium that can infect humans and animals. It has a high ability to develop resistance to several different antibiotics. In this study, 129 clinical specimens were collected from patients in three different hospitals in Baghdad during the period from October 13, 2020, to January 26, 2021. From all of these specimens, only 45 isolates showed cultural and biochemical characteristics that are similar to S. aureus. The identity of these isolates was further confirmed using specific primers for the S. aureus nuc gene. In addition, the susceptibility of these isolates to eleven virous antibiotics was studied. The results revealed that all S. aureus isolates demonstrated high resistance to cefoxitin, penicillin, and ceftazidime. On the other hand, the isolates showed virous susceptibility to the rest of the eight antibiotics. We also found that there were no antibiotics tested in this study that were able to kill all S. aureus isolates, and all isolates tested in this study were classified as MRSA.