Characterization of biofilm formation in uropathogenic Staphylococcus aureus and their association with antibiotic resistance

Abstract

IntroductionThe increase in antibiotic resistance and biofilm formation in Staphylococcus aureus is a serious public health problem, complicating the treatment of infections caused by these bacteria, including urinary tract infections (UTIs). This research aimed to assess the correlation between antibiotic resistance and the capacity for biofilm formation in S. aureus strains isolated from patients with UTIs. MethodsThe antibiotic susceptibility testing was conducted using disc diffusion and broth micro-dilution method. The blaZ and mecA genes were investigated in all penicillin and cefoxitin-resistant S. aureus strains, using PCR. Biofilm formation was investigated using the Congo red agar and microtitre plate methods. All S. aureus strains were screened for genes encoding adhesion and biofilm formation (spa, fnb AB, clfA, bap) and intercellular adhesin (icaADB and icaR). ResultsAmong 20 strains of S. aureus, 55% were found to be multidrug-resistant (MDR) and methicillin-resistant (MRSA). All strains were biofilm producers, including 55% moderate biofilm producers and 35% strong biofilm producers. A significant correlation (p-value <0.01) was observed between MDR and non-MDR strains in terms of biofilm production. All strains were sensitive to linezolid, and 20% exhibited the constitutive clindamycin resistance phenotype. The spa, fnbB, and clfA genes were present in all strains followed by the bap (95%) and fnbA (90%). The icaA (90%) and icaB (60%) genes were most detected. The coexistence of icaA, icaADB, and icaAD genes was significantly associated with MRSA strains. In contrast, the icaR gene was significantly detectable in the methicillin-susceptible group of strains. ConclusionThis study uncovered a significant association between the formation of biofilms by uropathogenic S. aureus and antibiotic resistance, highlighting a noteworthy concern for public health.