Novel determination of spa gene diversity and its molecular typing among Staphylococcus aureus Iraqi isolates...

Staphylococcus aureus is the most frequent agent causing nosocomial infections in Baghdad hospitals. This study aimed to determine S. aureus methicillin resistance, spa gene typing and phylogenic analysis in Iraqi S. aureus isolates. Two hundred samples including clinical (n = 100) and environmental (n = 100) specimens were collected. S. aureus isolates were identified using multiplex PCR amplification of femA and mecA (for methicillin-resistant S. aureus (MRSA) strains) genes. The spa gene was also amplified. Sequence alignment and identification of spa types was then obtained. Of 74 studied S. aureus isolates, 61 (82.43%) harboured the mecA gene (p < 0.001). A spa gene variation was detected in 41 (67.2%) of 61 (p 0.0011) MRSA and 6 (46.15%) of 13 methicillin-susceptible S. aureus isolates. Amino acid sequence analysis revealed a great change in amino acid pattern among local isolates compared to National Center for Biotechnology Information control. Some of the MRSA isolates had high-level similarity with t10214. No genetic relationship with the infection sources was observed. None of the environmental isolates had spa gene variations. Most S. aureus isolates were MRSA. The spa gene variations was significantly higher among clinical isolates. spa sequencing showed different tandem repeats in local MRSA isolates compared to global spa types. We conclude that there was no outbreak in hospital settings in the city of Baghdad. However, our data suggest that isolates from the hospital environment are highly clonal.