Canduela Miren J, Gallego Lucía, Sevillano Elena, Valderrey Cristina, Calvo Felícitas, Pérez Julia
Dpto. Inmunología, Microbiología y Parasitología, Facultad de Medicina y Odontología, Universidad del País Vasco, Bilbao, Spain.
J Antimicrob Chemother. 2006 Jun;57(6):1220-2. doi: 10.1093/jac/dkl129. Epub 2006 Apr 5.
To study the evolution between 1999 and 2002 and mechanisms of antibiotic resistance in a multidrug-resistant Acinetobacter baumannii clone predominant in isolates from elderly patients with respiratory tract infections.
Susceptibility to antimicrobials was determined using an agar dilution method. Bacterial clones were identified by PCR-fingerprinting and PFGE with ApaI. Carbapenemases were detected by phenotypic tests; by PCR with primers specific for bla (OXA-40), bla(IMP), bla(VIM-1) and bla(VIM-2); and by hybridization with DNA probes. Class 1 integrons were detected using PCR.
In 1999 isolates were grouped into two main genotypes: clone I (33%) and clone II (55%). These were also detected in 2002 with a different distribution: clone I (69%), clone II (22%). Resistance to amikacin, meropenem and imipenem increased significantly in clone I over this time, whereas clone II was not affected. In 2002, the incidence of bla(OXA-40) rose to 91% in clone I isolates with some also harbouring bla(VIM-2) and bla(IMP) genes. Different class 1 integrons were detected ranging in size from 550 to 1200 bp. No relationship was found between carbapenemases and class 1 integrons.
In elderly patients, a single clone became predominant among A. baumannii isolates, coinciding with an increase in antibiotic resistance rates. The majority of isolates harboured the bla(OXA-40) carbapenemase gene and some of them also harboured bla(VIM-2) and bla(IMP) genes. The presence of class 1 integrons also increased over time.
研究1999年至2002年间，在老年呼吸道感染患者分离出的多重耐药鲍曼不动杆菌克隆中抗生素耐药性的演变及机制。
采用琼脂稀释法测定抗菌药物敏感性。通过PCR指纹图谱和ApaI酶切脉冲场凝胶电泳（PFGE）鉴定细菌克隆。通过表型试验、使用针对bla(OXA - 40)、bla(IMP)、bla(VIM - 1)和bla(VIM - 2)的引物进行PCR以及与DNA探针杂交检测碳青霉烯酶。使用PCR检测1类整合子。
1999年分离株分为两种主要基因型：克隆I（33%）和克隆II（55%）。2002年也检测到这两种基因型，但分布不同：克隆I（69%），克隆II（22%）。在此期间，克隆I对阿米卡星、美罗培南和亚胺培南的耐药性显著增加，而克隆II未受影响。2002年，克隆I分离株中bla(OXA - 40)的发生率升至91%，部分还携带bla(VIM - 2)和bla(IMP)基因。检测到大小在550至1200 bp之间的不同1类整合子。未发现碳青霉烯酶与1类整合子之间存在关联。
在老年患者中，单一克隆在鲍曼不动杆菌分离株中占主导地位，同时抗生素耐药率增加。大多数分离株携带bla(OXA - 40)碳青霉烯酶基因，其中一些还携带bla(VIM - 2)和bla(IMP)基因。1类整合子的存在也随时间增加。
