凝固酶阴性葡萄球菌中葡萄球菌盒式染色体 mec 结构的多样性及其与耐药性的关系。

Diversity of staphylococcal cassette chromosome mec structures in coagulase-negative staphylococci and relationship to drug resistance.

机构信息

Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey Nuevo Leon 64460, Mexico.

Departamento de Biología Molecular y Bioingeniería, UAM Reynosa Aztlán, Universidad Autónoma de Tamaulipas, Tamaulipas, Mexico.

出版信息

J Med Microbiol. 2010 Mar;59(Pt 3):323-329. doi: 10.1099/jmm.0.015800-0. Epub 2009 Dec 10.

Abstract

The objective of this study was to determine the distribution of staphylococcal cassette chromosome mec (SCCmec) elements in meticillin-resistant coagulase-negative staphylococci (MR-CoNS) isolated from a tertiary-care hospital in Mexico and to examine the relationship to drug resistance. Fifty selected MR-CoNS isolates collected from catheters (n=15), blood (n=15), bone (n=9), bronchial lavage (n=2) and urine (n=2) and one isolate each from an abscess, cerebrospinal fluid, eye, pleural effusion, synovial fluid, tracheal aspirate and wound secretion were examined. Susceptibility testing was performed by the broth microdilution method. SCCmec types were determined by multiplex PCR and PFGE was carried out as described previously for Staphylococcus aureus. Among the MR-CoNS strains studied, the most frequently isolated species were Staphylococcus epidermidis (n=26) and Staphylococcus haemolyticus (n=13). Staphylococcus cohnii (n=5), Staphylococcus hominis (n=3), Staphylococcus sciuri (n=1), Staphylococcus pasteuri (n=1) and the recently described species Staphylococcus pettenkoferi (n=1) were also identified. The most frequent MR-CoNS genotype identified was SCCmec type IVa in S. epidermidis isolates, which also showed a high diversity in their PFGE patterns. A clone was found that amplified both SCCmec III and V elements in five isolates examined. The single MR S. pettenkoferi isolate harboured SCCmec type IVd and the single MR S. pasteuri isolate harboured SCCmec type I. The carriage of SCCmec type III was associated with resistance or intermediate resistance to meropenem (P <0.05). These results confirm the high prevalence of S. epidermidis SCCmec IVa and the high genetic diversity among MR-CoNS strains. As far as is known, this is the first report describing the newly identified S. pettenkoferi possessing SCCmec IVd and S. pasteuri harbouring SCCmec type I. MR-CoNS harbouring SCCmec type III were found to be more resistant to meropenem.

摘要

本研究旨在确定分离自墨西哥一家三级保健医院的耐甲氧西林凝固酶阴性葡萄球菌(MR-CoNS)中葡萄球菌盒式染色体 mec(SCCmec)元件的分布,并探讨其与耐药性的关系。从导管(n=15)、血液(n=15)、骨骼(n=9)、支气管灌洗(n=2)和尿液(n=2)中采集了 50 株选定的 MR-CoNS 分离株,每个脓肿、脑脊液、眼睛、胸腔积液、滑液、气管吸出物和伤口分泌物各分离一株。通过肉汤微量稀释法进行药敏试验。通过多重 PCR 确定 SCCmec 类型,并按照以前描述的金黄色葡萄球菌的方法进行 PFGE。在所研究的 MR-CoNS 菌株中,最常分离的菌种是表皮葡萄球菌(n=26)和溶血葡萄球菌(n=13)。还鉴定出科氏葡萄球菌(n=5)、人葡萄球菌(n=3)、松鼠葡萄球菌(n=1)、巴氏葡萄球菌(n=1)和最近描述的 pettenkoferi 葡萄球菌(n=1)。在表皮葡萄球菌分离株中最常见的 MR-CoNS 基因型是 SCCmec 类型 IVa,其 PFGE 模式也具有高度多样性。在 5 株被检测的分离株中发现了一个同时扩增 SCCmec III 和 V 元件的克隆。单个耐甲氧西林 pettenkoferi 分离株携带 SCCmec 类型 IVd,单个耐甲氧西林巴氏葡萄球菌携带 SCCmec 类型 I。携带 SCCmec 类型 III 与对美罗培南的耐药性或中介耐药性有关(P<0.05)。这些结果证实了表皮葡萄球菌 SCCmec IVa 的高流行率和 MR-CoNS 菌株的高遗传多样性。据了解,这是第一份描述新鉴定的 pettenkoferi 葡萄球菌携带 SCCmec IVd 和巴氏葡萄球菌携带 SCCmec 类型 I 的报告。携带 SCCmec 类型 III 的耐甲氧西林凝固酶阴性葡萄球菌对美罗培南的耐药性更高。

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