Abstract:

Objective To study the characteristics of drug susceptibility and biofilm formation ability of Corynebacterium striatum with different genotypes,and to provide a reference for clinical diagnosis and therapy. Methods Totally,36 isolates of Corynebacterium striatum were collected from January 2018 to December 2021,which included 21 isolates from sterile body fluid specimens and the other 15 isolates from clean middle urine specimens. Multilocus sequence typing（MLST） genotyping,drug susceptibility test（agar dilution method） to 10 agents and biofilm formation determination（MTT） were carried out. Results Totally,36 isolates of Corynebacterium striatum were isolated mainly from immuno-suppressed elder patients,9 genotypes were classified with MLST method,and ST6（36.1%） and ST2（25.0%） were the most popular genotypes. All the 36 isolates were multi-drug resistance（MDR） bacteria,and they were sensitive to vancomycin and linezolid（100%）. Most ST2 isolates were sensitive to tetracycline,while most ST6 isolates were sensitive to gentamicin and rifampin. The biofilm formation determination showed that all the 36 isolates could form biofilm on the polystyrene surface,but the ST2 ones had stronger biofilm formation ability compared with the other genotypes（P<0.05）. Conclusions Different genotypes of Corynebacterium striatum have different biofilm formation abilities and drug susceptibilities to commonly used antibiotics. In the process of clinical diagnosis and treatment,clinicians should pay more attention to the rational use of antibiotics,which will help to avoid opportunistic infections and nosocomial infections.

Key words: Corynebacterium striatum, Drug susceptibility, Multilocus sequence typing, Biofilm