In vitro susceptibility of chloramphenicol against methicillin-resistant staphylococcus aureus

ABSTRACT

To determine the in vitro susceptibility of chloramphenicol against methicillin-resistant Staphylococcus aureus. Cross-sectional study. Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from January to June 2012. One hundred and seventy four isolates of methicillin-resistant Staphylococcus aureus were included in this study using cefoxitin [30 microg] disc for detection. Minimum inhibitory concentration [MIC] of chloramphenicol against MRSA was determined by using E-strip [AB BIO DISK]. The susceptibility was determined by swabbing the Mueller-Hinton agar [MHA] plates with the resultant saline suspension of MRSA and applying E-strip of chloramphenicol from AB Biodisk Sweden and determining the MIC of chloramphenicol [in microg/ml]. Clinical and Laboratory Standards Institute [CLSI] recommendations of /= 32 microg/ml as resistant were followed in interpreting the results. Out of the 174 MRSA isolates, 132 [75.86%] isolates were susceptible to chloramphenicol with MICs of A[2] 8 microg/ml, 38 [21.84%] were resistant >/= 32 microg/ml while 4 [2.30%] were in intermediate range with MIC of 16 microg/ml. Chloramphenicol has shown good in vitro activity against MRSA and is likely to have a key role in the treatment of MRSA infections providing us a good alternative to newer expensive antimicrobials in resource limited countries