CAJ | 학술논문

目的研究碳青霉烯耐药摩根摩根菌的分子流行病学及其耐药机制.方法 2010年10月-2011年2月从杭州市中医院分离到7株碳青霉烯不敏感的摩根摩根菌.脉冲场凝胶电泳(PFGE)分析菌株之间的同源性；琼脂稀释法测定抗生素对细菌的最低抑菌浓度(MIC)；接合试验、质粒图谱分析、特异性PCR扩增和序列分析等研究细菌对碳青霉烯耐药的分子机制.结果分离自急诊监护病房的6株摩根摩根菌PFGE条带完全相同或相差1～3个条带；分离自重症监护病房的1株摩根摩根菌与其他6株PFGE条带差异明显.7株摩根摩根菌的耐药模式基本相同.亚胺培南、美罗培南和厄他培南的MIC值差异较大,分别为8μg/ml(耐药)、1μg/ml(敏感)和0.25～0.50μg/ml(敏感或中介耐药).7株摩根摩根菌对青霉素类、氨曲南和环丙沙星耐药,对头孢菌素类耐药或敏感,对阿米卡星敏感.接合试验使大肠埃希菌EC600对碳青霉烯类抗生素由敏感变为耐药,对其他β-内酰胺类抗生素也均耐药.摩根摩根菌及转移接合子均含有一个约为60kb的质粒.PCR扩增及测序表明摩根摩根菌及转移接合子均产KPC-2型碳青霉烯酶,且携带qnrS1基因.结论首次在摩根摩根菌中检测到KPC-2型碳青霉烯酶,KPC-2是引起摩根摩根菌对碳青霉烯类不敏感的主要原因.
목적 연구탄청매희내약마근마근균적분자류행병학급기내약궤제.방법 2010년10월-2011년2월종항주시중의원분리도7주탄청매희불민감적마근마근균.맥충장응효전영(PFGE)분석균주지간적동원성；경지희석법측정항생소대세균적최저억균농도(MIC)；접합시험、질립도보분석、특이성PCR확증화서렬분석등연구세균대탄청매희내약적분자궤제.결과 분리자급진감호병방적6주마근마근균PFGE조대완전상동혹상차1～3개조대；분리자중증감호병방적1주마근마근균여기타6주PFGE조대차이명현.7주마근마근균적내약모식기본상동.아알배남、미라배남화액타배남적MIC치차이교대,분별위8μg/ml(내약)、1μg/ml(민감)화0.25～0.50μg/ml(민감혹중개내약).7주마근마근균대청매소류、안곡남화배병사성내약,대두포균소류내약혹민감,대아미잡성민감.접합시험사대장애희균EC600대탄청매희류항생소유민감변위내약,대기타β-내선알류항생소야균내약.마근마근균급전이접합자균함유일개약위60kb적질립.PCR확증급측서표명마근마근균급전이접합자균산KPC-2형탄청매희매,차휴대qnrS1기인.결론 수차재마근마근균중검측도KPC-2형탄청매희매,KPC-2시인기마근마근균대탄청매희류불민감적주요원인.
Objective To investigate the molecular epidemiology and mechanisms of carbapenem resistance of Morganella morganii.Methods Seven carbapenem-non-susceptible M.morganii were isolated from Hangzhou Traditional Chinese Medicine Hospital from October 2010 to February 2011.Pulsed-field gel electrophoresis (PFGE) was performed to analysis the molecular epidemiology of isolates.Antibiotic susceptibilities were determined by agar dilution method.Conjugation experiments were carried out in mixed broth cultures.Plasmid DNA was obtained by an alkalinelysis technique and examined by electrophoresis.Specific PCRs and DNA sequencing were preformed to confirm the genotype of β-lactamases.Results PFGE indicated that 6 M.morganii isolates from emergency care unit were indistinguishable or closely related and 1 isolate from intensive care unit was distinguishable.Seven M.morganii showed similar antibiotic susceptibility patterns.M.morganii isolates were resistant to imipenem,were susceptible to meropenem,and were susceptible or intermediate resistant to ertapenem,with MICs of 8 μg/ml,1 μg/ml,and 0.25-0.50 μg/ml,respectively.M.morganii isolates were resistant to penicillins,aztreonam,and ciprofloxacin,were resistant or susceptible to cephalosporins,and were susceptible to amikacin.E.coli (EC600) acquired an approximately 60 kb plasmid from M.morganii by conjugation studies and resistant or intermediate resistant to carbapenems and other β-lactams.PCRs and DNA sequence analysis confirmed that all M.morganii isolates and their E. coli transconjugants produced the KPC-2 carbapenemase and carried the qnrS1 gene.Conclusion It is the first detection of KPC-2 in M.morganii isolates.Production of KPC-2 mainly contributed to the carbapenem resistance in M.morganii.