Prevalence and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus and coagulasenegative Staphylococci isolated from blood culture in Limpopo Province, South Africa

Abstract

Abstract
Background: Methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase negative
staphylococci (MRCoNS) are the important nosocomial infectious agents. There is a growing concern about the rapid
rise in the resistance of Staphylococcus to presently available antimicrobial agents.
Objective: The objective of this study was to evaluate the prevalence rate of MRSA and MR CoNS and their rate of
resistance to different anti-staphylococcal antibiotics used broadly for treatment.
Methods: This study was carried out between November 2008 and December 2011 in Limpopo Province of South
Africa. A total of nine hundred (900) Staphylococcus isolates were isolated from 5980 blood culture collected. The
antibiotic susceptibility pattern of all the confirmed strains was determined by Kirby Bauer disc diffusion method.
Screening Test for MRSA was performed following NCCLS guidelines using Oxacillin agar. Vancomycin resistance
was tested by vancomycin agar screening test. ß-lactamase production was determined by iodometric strip method.
Results: MRSA was responsible for 9.89% (89 /900) of the infections while MRCoNS was responsible for 90.1 %
(811/900). MRSA was resistant to cephalosporins, gentamycin, fluoroquinolones and even imipinem, so these are less
effective in the treatment of MRSA infections. MRCoNS was resistant to augmentin, gentamycin and
chloramphenicol.
Conclusions: The percentage of drug resistant isolates of both Staphylococcus aureus and coagulase negative
Staphylococcus were seen to be high. Most of the clinical isolates of MRSA were resistant to cephalosporins,
gentamicin, fluoroquinolones and even to imipenem, so these are less effective in the treatment of MRSA infections.
Vancomycin use should be limited to those cases where they are clearly needed. Ethiop. J. Health Dev.
2015;29(1):37-42]