Frequency of Inducible Clindamycin Resistance in Staphylococcus haemolyticus Isolated from Surgical Wounds Infections Using D-test and Molecular Methods in Al-Basrah, Iraq

Aims: S. haemolyticus is generally considered an opportunistic pathogen that is strongly associated with immunocompromised individuals. S. haemolyticus is ranked as a highly antibiotic-resistant pathogen for various types of antibiotics. Current study aimed to investigate the frequency of inducible clindamycin resistance in S. haemolyticus isolated from surgical wounds infections using D-test and molecular methods in Al-Basrah, Iraq. Materials Methods: 200 surgical wound swabs were collected from Ports General Hospital in Basrah, Iraq. The coagulase-negative staphylococcal strains were identified using methods like oxidase, catalase, hemolysis, and coagulase tests and confirmed by Vitek®2 system. Methicillin resistance and inducible clindamycin resistance were detected according to disk diffusion method based on CLSI guidelines. Moreover, molecular approaches was performed to confirm methicillin and inducible clindamycin resistance results. Findings: Out of 200 cases, 75 surgical wound swabs (37.5%) showed positive bacterial cultures. The highest frequency of isolates belonged to Pseudomonas aeruginosa (25.3%), Staphylococcus epidermidis (17.3%), Staphylococcus aureus (14.7%) and Escherichia coli (13.3%), respectively. Out of eight S. haemolyticus isolates, only 5 isolates (62.5%) showed inhibitory resistance criteria for both oxacillin and cefoxitin. Furthermore, 3 S. haemolyticus isolates (37.5%) were erythromycin-resistant and clindamycin sensitive with D-test positive with iMLSB resistance phenotype. While 2 isolates (25.0%) showed cMLSB resistance phenotype and 3 (37.5%) isolates were shown MSB resistance phenotypes. The most frequent resistance genes of S. haemolyticus strains were mecA (62.5%), ermA (62.5%), ermB (50.0%), respectively. Conclusion: D-test and molecular technique are appropriate for detection of inducible clindamycin resistance in S. haemolyticus strains.