[Investigation of Antibiotic Resistance Profiles, Molecular Epidemiology and Biofilm Formation in Corynebacterium...

This study aimed to evaluate the antibiotic resistance profiles, molecular epidemiology, and biofilm formation of Corynebacterium striatum isolated from clinical samples in our hospital. A total of 132 C.striatum isolates were included in the study. Antimicrobial susceptibility testing was performed using the disk diffusion method in accordance with the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Resistance genes were determined using polymerase chain reaction. Biofilm formation was investigated using the microtiter plate method. Clonal relationships in isolates were examined using the Pulsed Field Gel Electrophoresis (PFGE) method. All isolates were found to be susceptible to vancomycin and linezolid. Resistance rates among the isolates were quite high, with resistance to ciprofloxacin, penicillin, clindamycin, rifampin, tetracycline, gentamicin and erythromycin observed in 100.0%, 98.5%, 97.0%, 99.2%, 100.0%, 90.2%, and 74.2% of the isolates, respectively. bla/ampC, ermX, aac(3)-XI, aphA1, gyrA, and tetA genes were detected as 99.2%, 96.2%, 93.2%, 91.7%, 100.0% and 43.8%, respectively. In isolates positive for the aphA1 and aac(3)-XI genes, the gentamicin resistance rate and in isolates positive for the ermX gene, the clindamycin and erythromycin resistance rates were found as significantly higher (p< 0.05). Biofim formation was detected in 28% of the isolates. The similarity ratio of the isolates was determined to be 85%. The four main clusters, A, B, C, and D showed 32 different PFGE patterns. The clustering rate was determined to be 96.0%. In conclusion, the high rates of phenotypic and genotypic antimicrobial resistance among C.striatum strains in our hospital are quite remarkable.