Phenotypic and genotypic characterization of biofilm formation in Staphylococcus haemolyticus isolated from urinary tract infections and their antibiotic resistance patterns.

Abstract This study aimed to establish the correlation between antibiotic resistance and the ability of Staphylococcus haemolyticusstrains to form biofilms and to examine the impact of sub-inhibitory concentrations of antibiotics (sub-MICs) on biofilm formation. Antibiotic susceptibility testing was conducted using the disk diffusion method, and biofilm formation was determined using Congo red agar and microtitre plate methods. Biofilm-associated genes and screening for blaZ and mecA in the genomes of all penicillin- and cefoxitin-resistant S. haemolyticus isolates were detected using polymerase chain reaction (PCR). Among the 21 S. haemolyticus isolates, 85.71% were multidrug-resistant (MDR) and methicillin-resistant (MRSH). The majority of strains were biofilm producers, including 43% of moderate biofilm producers and 5% of strong biofilm producers. A significant correlation was observed between MRSH and MSSH isolates in terms of biofilm production. All strains were sensitive to linezolid and 22.2 % exhibited an inducible clindamycin resistance phenotype. The impact of sub-MICs of antibiotics on the prevention of biofilm growth is a matter of debate; vancomycin, gentamicin, and ciprofloxacin at sub-MICs tended to promote biofilm formation in most strains. The eno gene was present in 76.2% of S. haemolyticus strains, followed by aap (42.8%), icaD(42.8%), and atlE (23.8%). Meanwhile, 9.5 % of the isolates carried embPgene. The findings of this study revealed a strong correlation between the biofilm-forming ability and antibiotic resistance in S. haemolyticus, which underline a crucial public health issue. Furthermore, this research will play an essential role in controlling the dissemination of antibiotic resistance in S. hemolyticus strains.