Antimicrobial Susceptibility Patterns of Staphylococcus aureus Strains Isolated at the Namibia Institute of Pathology from 2012 to 2014

摘要

Staphylococcus aureus (S. aureus) is known to acquire resistance to new drugs and continues to defy at-tempts to control it. Infections caused by antibiotic resistant strains of S. aureus have reached epidemic proportions globally and the increasing rates of antimicrobial resistance are resulting in fewer treatment options. Methicillin resistant S. aureus (MRSA) has also emerged as a serious therapeutic problem worldwide. However, data on the antimicrobial susceptibility patterns of this bacterium over a period of time in Namibia are not available. A descriptive retrospective study was therefore conducted to investigate the antimicrobial susceptibility patterns of 600 Staphylococcus aureus strains isolated at the Namibia Institute of Pathology (NIP) from January 2012 to December 2014. The results showed that a high proportion of isolates were resistant to penicillin (92.4%) and cotrimoxazole (44.9%), while the antibiotics to which the isolates were least resistant included vancomycin (0%), fusidic acid (0.3%) and ciprofloxacin (4.4%). Methicillin resistance was observed in 13.5% of the staphylococcal isolates. Apart from clindamycin (P value = 0.039) and cotrimoxazole (P value = 0.030), the susceptibility patterns of the antibiotics did not differ significantly over the three years. Moreover, wound swabs and sputum were the clinical samples from which S. aureus was most commonly isolated at NIP. The results from this study suggest that continuous local surveillance on the resistance patterns of S. aureus should be performed on regular basis in Namibia, in order to have adequate information for the empirical treatment of S. aureus infections.