Molecular analysis and susceptibility pattern of meticillin-resistant Staphylococcus aureus strains in emergency department patients and related risk factors in Iran.

BACKGROUND

Meticillin-resistant Staphylococcus aureus (MRSA) has become widespread in the hospital and in the community. Nasal colonization with MRSA has been identified as a risk factor for MRSA infection.

AIM

To determine the prevalence of nasal colonization with MRSA among adult patients in the emergency department (ED) by considering the risk factors for MRSA carriage and antibiotic susceptibility patterns.

METHODS

A cross-sectional study was conducted among 810 patients in the ED in Kashan, Iran. A questionnaire concerning the risk factors for MRSA colonization was completed for each patient. Specimens were obtained from the anterior nares. A multiplex polymerase chain reaction (PCR) assay was used for SCCmec typing, and a PCR assay was used to detect Panton-Valentine leukocidin (PVL) genes. MRSA susceptibility to amikacin, clindamycin, gentamicin, ciprofloxacin, penicillin, trimethoprim/sulfamethoxazole, erythromycin, tetracycline, vancomycin and cefoxitin was determined by the disc diffusion method.

FINDINGS

Two hundred and ninety-six (36.5%) and 26 (3.2%) out of 810 patients were S. aureus and MRSA nasal carriers, respectively. Of these, nine (34.6%), seven (26.9%), two (7.7%), two (7.7%), two (7.7%), one (3.8%) and one (3.8%) MRSA isolates were classified as type V, III, I, IVb, IVh, II and IVa, respectively, and seven (26.9%) MRSA isolates were non-typeable. PVL genes were not detected. All MRSA isolates were multi-drug resistant.

CONCLUSION

A significant association was found between previous hospitalization, use of urinary and/or venous catheters and MRSA colonization. Further work on the epidemiology and risk factors for MRSA nasal colonization may be useful to guide the treatment and prevention of MRSA infections.