Homology and drug resistance gene analysis of Group B Streptococcus resistance induced by clindamycin

Abstract

Objectives To investigate the homology and drug resistance gene of Group B Streptococcus (GBS) Resistance induced by Clindamycin and provide basic data for clinical prevention and treatment of GBS Resistance infection induced by Clindamycin. Methods 921 strains of GBS were isolated at Obstetrics & Gynecology Hospital of Fudan University from January, 2014 to December, 2015. VITEK2-compact automatic bacterial susceptibility instrument was used to test their sensitivity to 7 antibacterial drugs. 63 positive strains were chosen through D-inhibition zone trial which were drug resistant to Erythromycin and susceptible or intermediary to Clindamycin. The strain′s sequence type was identified by the method of multilocus sequence typing (MLST typing). The drug resistance genes mefA & ermB to Erythromycin were detected by using PCR method. The analysis was carried out to reveal the relevance to drug resistance, multilocus sequence typing and drug resistance gene. Results Among 921 strains of GBS, the drug resistance rate was respectively 53.4% (492/921 strains) to Erythromycin, 50.2% (462/921 strains) to Clindamycin, 34.7% (320/921 strains) to Levofloxacin and 7.5% (69/921 strains) to Nitrofurantoin. The drug resistance rate of Levofloxacin for 63 GBS strains was 27.0% (17/63 strains) and no drug resistant strain was found to Penicillin, Vancomycin & Nitrofurantoin. 12 different ST types were involved in total, including a new ST type: ST1072. The most common ones were ST12 (30.1%) (20/63 strains) & ST19 (25.4%) (16/63 strains). The drug resistance rate of Levofloxacin with ST19 (75.0%) (12/16 strains) was much higher than that of other ST types. The relevance ratio of mefA and ermB among 63 GBS strains was respectively 27.0% (17/63 strains) and 41.3% (26/63 strains). Conclusions The genetic diversity existed in Group B Streptococcus resistance induced by Clindamycin detected in this study. There was significant difference on drug resistance and relevant drug resistant genes among different ST types.(Chin J Lab Med, 2018, 41: 24-28) Key words: GroupB Streptococcus; Multilocus Sequence Typing; Drug Resistance Gene