Need of Testing Mupirocin Susceptibility Pattern of Staphylococcus aureus from Clinical Isolates in a Tertiary Care Teaching Institute

Introduction : Staphylococcus aureus is an important cause of a variety of infections, ranging from skin and soft tissue infections to serious, life-threatening bloodstream infections. Methicillin Resistant Staphylococcus aureus (MRSA) is involved in serious infections as well as nosocomial outbreaks. Mupirocin is drug used for decolonization of the carrier state as well as for topical treatment of MRSA infections. Nowadays, mupirocin resistance is increasing due to inappropriate usage. In the present study, we have demonstrated mupirocin resistance by simultaneous use of mupirocin discs with concentrations of 5 μg and 200 μg in S. aureus clinical isolates. Material and Methods: A prospective study for a period of six months was conducted in a tertiary care teaching hospital in Sawarde, Ratnagiri. S. aureus isolates obtained from 993 clinical specimens were processed further as per standard operating procedures in the Microbiology Laboratory for mupirocin resistance and interpreted with the help of Clinical and Laboratory Standards Institute (CLSI) guidelines. Results: In 993 clinical samples we got 100 isolates of S. aureus, 67% were MRSA and 33% were MSSA (Methicillin Sensitive Staphylococcus aureus). The maximum number of MRSA isolates were recovered from pus 32 (47.76%), followed by wound swab 17 (25.37%) and blood 9 (13.43%). Among 12 mupirocin-resistant MRSA isolates, 7 (10.44%) exhibited low-level resistance to mupirocin, and 5 (7.46%) isolates were found to be high-level mupirocin-resistant. In MSSA strains, no mupirocin resistance was observed. Conclusion: The use of topical ointment mupirocin is an effective modality for destroying MRSA in carriers. Differentiating between the two types of resistance in mupirocin (MuL and MuH i.e. Mupirocin Low Level Resistance and Mupirocin High Level Resistance) has a notable therapeutic impact. Due to the alarming rise in antimicrobial resistance, hospital laboratories should detect the susceptibility of S. aureus isolates to the drug mupirocin.