Freitas F, Machado E, Ribeiro T G, Novais Â, Peixe L
REQUIMTE, Laboratório de Microbiologia, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
Eur J Clin Microbiol Infect Dis. 2014 Apr;33(4):551-8. doi: 10.1007/s10096-013-1983-9. Epub 2013 Oct 7.
We investigated the occurrence, diversity and molecular epidemiology of genes coding for acquired AmpC β-lactamases (qAmpC) among clinical isolates of Enterobacteriaceae lacking inducible chromosomal AmpCs in Portugal. A total of 675 isolates non-susceptible to broad-spectrum cephalosporins obtained from four hospitals and three community laboratories during a 7-year period (2002-2008) were analysed. The presence of genes coding for qAmpC was investigated by phenotypic criteria, polymerase chain reaction (PCR) and sequencing. Bacterial identification, antibiotic susceptibility testing, conjugation assays and clonal analysis were performed by standard procedures. The presence of bla(qAmpC) genes was detected in 50 % (50/100; 41 Klebsiella pneumoniae, 5 Escherichia coli, 4 Klebsiella oxytoca) of the presumptive qAmpC producers. DHA-1, detected in those species, was the most prevalent qAmpC (94 %, 47/50), being identified since 2003 and throughout the studied period in different institutions. Despite the high clonal diversity observed, three DHA-1-producing Klebsiella spp. clones were more frequently identified. CMY-2 (6 %, 3/50) was observed in B1-E. coli clones. Conjugative transfer was only observed in one (2 %) CMY-2-producing isolate. Most qAmpC producers (94 %, 47/50) co-expressed SHV-type and/or OXA-1 or CTX-M-32 extended-spectrum β-lactamases (ESBLs). To the authors' knowledge, this is the first description of the molecular epidemiology and the long-term dissemination of qAmpC-producing Enterobacteriaceae in Portuguese clinical settings, highlighting an evolution towards a more complex epidemiological situation regarding cephalosporin resistance in Portugal.
我们调查了葡萄牙缺乏可诱导染色体AmpC的肠杆菌科临床分离株中编码获得性AmpCβ-内酰胺酶（qAmpC）的基因的发生情况、多样性和分子流行病学。分析了在7年期间（2002 - 2008年）从四家医院和三个社区实验室获得的675株对广谱头孢菌素不敏感的分离株。通过表型标准、聚合酶链反应（PCR）和测序研究编码qAmpC的基因的存在情况。通过标准程序进行细菌鉴定、抗生素敏感性测试、接合试验和克隆分析。在推定的qAmpC产生菌中，50%（50/100；41株肺炎克雷伯菌、5株大肠埃希菌、4株产酸克雷伯菌）检测到bla（qAmpC）基因。在这些菌种中检测到的DHA - 1是最常见的qAmpC（94%，47/50），自2003年以来在整个研究期间不同机构中均有发现。尽管观察到高度的克隆多样性，但三个产DHA - 1的克雷伯菌属克隆更常被鉴定出来。在B1 - 大肠埃希菌克隆中观察到CMY - 2（6%，3/50）。仅在一株（2%）产CMY - 2的分离株中观察到接合转移。大多数qAmpC产生菌（94%，47/50）共表达SHV型和/或OXA - 1或CTX - M - 32超广谱β-内酰胺酶（ESBLs）。据作者所知，这是葡萄牙临床环境中产qAmpC肠杆菌科的分子流行病学和长期传播的首次描述，突出了葡萄牙头孢菌素耐药性向更复杂流行病学情况的演变。
