Akademik Veri Yönetim Sistemi
11th International "Artemis" Scientific Research Congress, Bucuresti, Romanya, 27 - 28 Şubat 2025, cilt.1, ss.77-78
Staphylococcus hominis is a coagulase-negative staphylococcus prevalent in the human body, mainly in moist and oily skin and mucosal areas. This opportunistic pathogen causes nosocomial infections in healthcare facilities, especially in newborns, immunocompromised and immunosuppressed patients. The development of resistance to methicillin and other antibiotics commonly used in the treatment of S. hominis complicates treatment processes, increases healthcare costs and poses a significant health threat, especially in intensive care units. This bacterium, which can enter the bloodstream through medical devices and equipment, forms a biofilm that enables it to persist on these devices and lining of blood vessels, leading to chronic infections such as bacteremia and endocarditis. Therefore, understanding the pathogenicity and antibiotic resistance of S. hominis is of crucial to effectively combat such clinical cases. The susceptibility of antibiotics used in treatment and their effect on biofilm production ability were investigated in this study. For these objectives, 25 S. hominis isolates from blood were studied. Antibiotic susceptibilities to clindamycin, chloramphenicol, tetracycline, trimethoprim-sulfamethoxazole and vancomycin were determined by disk diffusion method. The minimum inhibition concentration (MIC) of the antibiotics to which they were susceptible were determined on 96 well microtiter plate. Biofilm production of S. hominis isolates at ½ MIC concentrations (sub-MIC) was investigated by crystal violet binding assay. All isolates (100%, n=25) were resistant to clindamycin and sensitive to chloramphenicol. Tetracycline 60.0% (n=15), trimethoprim-sulfamethoxazole 32.0% (n=8) and vancomycin 76.0% (n=19) were susceptible. Chloramphenicol 36.0% (n=9), tetracycline 4.0% (n=1), trimethoprim-sulfamethoxazole 12.0% (n=3) and vancomycin 68.42% (n=13) induced biofilm production (p<0.05). Induction of biofilm production is a physicochemical response of S. hominis to the antibiotic in the environment. Increased biofilm production is an adaptation of the bacteria in the biofilm matrix to reduce their exposure to antibiotics in the external environment. Thus, S. hominis develops chronic and recurrent infections due to non-inhibitory concentrations of antibiotics enhancing biofilm production.