Nicholas Asiimwe, Kim Yu Kyung, Lee Won-Kil, Selasi Gati Noble, Na Seok Hyeon, Kwon Hyo Il, Kim Yoo Jeong, Lee Hae Sook, Song Kyung Eun, Shin Jeong Hwan, Lee Je Chul
Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
Department of Laboratory Medicine, Yeungnam University College of Medicine, Daegu, Republic of Korea.
PLoS One. 2017 Mar 29;12(3):e0174716. doi: 10.1371/journal.pone.0174716. eCollection 2017.
Clostridium difficile is one of the main etiological agents causing antibiotic-associated diarrhea. This study investigated the genetic diversity of 70 toxigenic C. difficile isolates from two Korean hospitals by employing toxinotyping, ribotyping, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Toxin gene amplification resulted in 68 A⁺B⁺ and two A-B+ isolates. Most isolates (95.7-100%) were susceptible to daptomycin, metronidazole, and vancomycin. Seventy C. difficile isolates were classified into five toxinotypes, 19 ribotypes, 16 sequence types (STs), and 33 arbitrary pulsotypes. All C. difficile isolates of ribotype 018 (n = 38) were classified into ST17, which was the most prevalent ST in both hospitals. However, C. difficile isolates of ST17 (ribotype 018) exhibited pulsotypes that differed by hospital. ST2 (ribotype 014/020), 8 (ribotypes 002), 17 (ribotype 018), and 35 (ribotypes 015) were detected in both hospitals, whereas other STs were unique to each hospital. Statistical comparison of the different typing methods revealed that ribotyping and PFGE were highly predictive of STs. In conclusion, our epidemiological study indicates that C. difficile infections in both hospitals are associated with the persistence of endemic clones coupled with the emergence of many unique clones. A combination of MLST with PFGE or ribotyping could be useful for monitoring epidemic C. difficile strains and the emergence of new clones in hospitals.
艰难梭菌是引起抗生素相关性腹泻的主要病原体之一。本研究通过毒素分型、核糖体分型、多位点序列分型（MLST）和脉冲场凝胶电泳（PFGE），对来自韩国两家医院的70株产毒素艰难梭菌分离株的遗传多样性进行了调查。毒素基因扩增结果显示，有68株为A⁺B⁺型，两株为A-B⁺型。大多数分离株（95.7 - 100%）对达托霉素、甲硝唑和万古霉素敏感。70株艰难梭菌分离株被分为五种毒素型、19种核糖体型、16种序列型（STs）和33种任意脉冲型。所有核糖体型018的艰难梭菌分离株（n = 38）均被归类为ST17，这是两家医院中最常见的ST型。然而，ST17（核糖体型018）的艰难梭菌分离株在不同医院表现出不同的脉冲型。ST2（核糖体型014/020）、8（核糖体型002）、17（核糖体型018）和35（核糖体型015）在两家医院均有检测到，而其他ST型则各医院独有。不同分型方法的统计学比较显示，核糖体分型和PFGE对ST型具有高度预测性。总之，我们的流行病学研究表明，两家医院的艰难梭菌感染与地方性克隆的持续存在以及许多独特克隆的出现有关。MLST与PFGE或核糖体分型相结合，可能有助于监测医院中艰难梭菌流行菌株和新克隆的出现。
