Resistance to Mupirocin among Methicillin Resistant Staphylococcus Aureus Isolates from Community Acquired Infections, Hospital Acquired Infections, and colonized Health Care Workers

Abstract

Key words: Methicillin-resistant S. aureus (MRSA), Mupirocin, Resistance Background: Mupirocin is prescribed as a topical treatment of Staphylococcus aureus infections as well as in decolonization of methicillin-resistant S. aureus (MRSA) in both patients and health care workers (HCWs). Availability and increased use of this drug has led to emergence of resistance especially among MRSA compared to methicillin sensitive S. aureus (MSSA). Objectives: Our study aimed to evaluate the prevalence of mupirocin resistant MRSA isolated from clinical infections and from colonized HCWs. Methodology: Between January to August 2017, 61 MRSA isolates were collected. Mupirocin MICs were detected using mupirocin E-test. mupA PCR was performed for resistant isolates. Results: 86.9%of MRSA were isolated from clinical infections; 22.9% were Community acquired (CA-MRSA) and 64% were Health Care acquired (HCA-MRSA). 13.1% of total isolated MRSA were from HCWs. 23% of all MRSA were mupirocin resistant. The percentages of mupirocin resistance in CA-MRSA, HCA-MRSA, and MRSA nasal carriers of HCWs were 1.6%, 18.1%, 3.3% of the total Mupirocin resistant MRSA, respectively. 14.8% of MRSA showed low level resistance, while 8.2% were high level Mupirocin resistant. MupA gene was detected in 42.9% of strains with high level mupirocin resistance. Conclusions: Routine MRSA testing for mupirocin resistance is recommended for early detection and control of the spread of resistance.