engleski

mecA-positive methicillin-sensitive Staphylococcus aureus clinical isolates in Zenica-Doboj Canton, Bosnia and Herzegovina

Abstract Forty-four mecA-positive and eight mecA-negative Staphylococcus aureus isolates confirmed by PCR were further tested by disc- diffusion (DD) oxacillin and cefoxitin, oxacillin Epsilon (E)- test, and oxacillin and cefoxitin minimal inhibitory concentration (MIC) Strip methicillin- resistant phenotype in S. aureus (MRSA) tests. Among 44 mecA-positive S. aureus isolates, two (4·5%) were detected as MRSA by DD-oxacillin, 17 (38·6%) by DD- cefoxitin test, and seven (15·9%) by the E- test. In the cefoxitin MIC Strip MRSA test, 19 (43·2%) isolates were resistant. In the oxacillin MIC Strip MRSA test, 18 (40·9%) isolates were resistant and 26 (59·1%) were sensitive, i.e. oxacillin-sensitive MRSA (OS- MRSA) (MIC range 0·25- ≤0·25 mg/l). Fifteen out of 26 OS-MRSA (57·7%) belonged to spa-CC 355/595, 78% of which belonged to the largest PFGE clone. Some discrepancies between the phenotypic methods for MRSA identification obtained in this study were caused by large proportion of OS-MRSA. Misidentification of OS- MRSA as MSSA might result in an appearance of highly resistant MRSA in patients treated with beta-lactam antibiotics.

Antimicrobial resistance;; MRSA; spa-CC;

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