Antimicrobial resistance analysis of Streptococcus suis strains isolated from human in Zhejiang Province / 中华传染病杂志

ABSTRACT

Objective:To understand the in vitro antimicrobial resistance and resistance phenotypes profile of Streptococcus suis strains isolated from human in Zhejiang Province. Methods:The strains of sporadic Streptococcus suis infections were isolated during 2005 to 2021 in Zhejiang Province, and were subjected to antimicrobial resistance analysis using agar dilution method. Polymerase chain reaction (PCR) technology was also used to detect 70 resistance genes including tetracyclines, macrolides and aminoglycosides. Results:The results of antimicrobial resistance analysis showed that these strains were sensitive to eleven kinds of antimicrobial agents with a sensitivity rate ≥96.8%, including cefepime, cefotaxime, ceftriaxone, chloramphenicol, daptomycin, ertapenem, levofloxacin, linezolid, meropenem, penicillin and vancomycin. These strains were mainly resistant to tetracycline, clindamycin, azithromycin and erythromycin, especially resistant to tetracycline with a rate of 93.5%(29/31). Fourteen strains (45.2%) exhibited multidrug resistant patterns. The PCR analysis of 70 drug resistance genes showed that 14(20.0%) different resistance genes were detected. The highest detection rate of resistant genes came from tetracycline, including tet ( O) gene (58.1%, 18/31), tet ( M) gene (48.4%, 15/31), tet ( 40) gene (35.5%, 11/31), followed by ermB gene (41.9%, 13/31) in the class of macrolide. Fourteen strains (45.2%) with more than three drug resistance genes were detected, of which eight strains (25.8%) detected 10 drug resistance genes. The analysis of antibiotic resistance and resistance phenotypes profile showed that tet ( M)+ ST7 accounted for 35.5%(11/31), tet( O)+ tet( 40)+ ermB+ mef( A)+ mef( A/ E)+ msrD+ Ant( 6)- Ⅰb+ aph( 3′)- Ⅲa+ aadB+ sat4+ ST7 accounted for 25.8%(8/31). Conclusions:The antimicrobial resistance and resistance phenotypes profile of sporadic Streptococcus suis strains isolated from human in Zhejiang Province are endemic, with mainly two types of characteristic genetic cloning of drug resistance genes.