Men T-Y, Wang J-N, Li H, Gu Y, Xing T-H, Peng Z-H, Zhong L
Department of Urology, Shandong University Affiliated Shandong Province Qianfoshan Hospital, Jinan, China.
Transpl Infect Dis. 2013 Feb;15(1):14-21. doi: 10.1111/tid.12001. Epub 2012 Sep 26.
Multidrug-resistant (MDR) gram-negative bacilli pose a serious and rapidly emerging threat to recipients of solid organ transplants (SOTs). However, extended-spectrum β-lactamases (ESBLs), as one of the cardinal mechanisms of resistance to antimicrobial agents in SOT recipients, remain obscure. The aim of this study was to investigate the prevalence of strains producing ESBLs in SOT patients with MDR gram-negative bacilli infections and to identify the ESBL genes carried by them.
Isolates from various clinical specimens of SOT recipients were identified using the VITEK 2 system, and their antibiotic sensitivity was determined by the 2-fold agar dilution method. Isolates suspected of producing ESBL enzymes were tested by an ESBL phenotypic confirmatory method, and the ESBL genotypes were determined by the polymerase chain reaction and sequencing.
A total of 80 MDR gram-negative strains were isolated from 350 SOT recipients. Among these strains, 42 (52.5%) had an ESBL-positive phenotype; 33 (42.3%) patients with ESBL-positive infection were found. Molecular analysis showed that most of the isolates harbored blaCTX-M-9 (78.6%), blaTEM (81.0%), and blaSHV (69.0%) genes. All the ESBL-producing strains were susceptible to carbapenems.
MDR gram-negative isolates from SOT recipients are frequently ESBL producers. TEM and CTX-M9 were the predominant ESBL types.
多重耐药（MDR）革兰氏阴性杆菌对实体器官移植（SOT）受者构成了严重且迅速出现的威胁。然而，超广谱β-内酰胺酶（ESBLs）作为SOT受者对抗菌药物耐药的主要机制之一，仍不清楚。本研究的目的是调查多重耐药革兰氏阴性杆菌感染的SOT患者中产生ESBLs菌株的流行情况，并鉴定它们携带的ESBL基因。
使用VITEK 2系统对SOT受者各种临床标本中的分离株进行鉴定，并通过2倍琼脂稀释法测定其抗生素敏感性。对疑似产生ESBL酶的分离株采用ESBL表型确证方法进行检测，并通过聚合酶链反应和测序确定ESBL基因型。
从350名SOT受者中总共分离出80株多重耐药革兰氏阴性菌株。在这些菌株中，42株（52.5%）具有ESBL阳性表型；发现33例（42.3%）患者感染了ESBL阳性菌株。分子分析表明，大多数分离株携带blaCTX-M-9（78.6%）、blaTEM（81.0%）和blaSHV（69.0%）基因。所有产ESBLs菌株均对碳青霉烯类药物敏感。
来自SOT受者的多重耐药革兰氏阴性分离株经常产生ESBLs。TEM和CTX-M9是主要的ESBL类型。
