Department of Innovative Molecular Diagnostics, University of Applied Sciences Leiden, Leiden, the Netherlands.
Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
J Med Microbiol. 2018 Jul;67(7):915-921. doi: 10.1099/jmm.0.000776. Epub 2018 Jun 6.
Staphylococcus haemolyticus has emerged as a highly antimicrobial-resistant healthcare-associated pathogen, in particular for patients admitted to neonatal intensive care. The objective of this study was to study the nature of SCCmec types among MDR-SH strains isolated from paediatric patients.
S. haemolyticus strains (n=60) were isolated from paediatric patients. Antibiotic resistance patterns were established using the disk agar diffusion and micro-broth dilution methods. SCCmec typing was performed using whole-genome sequencing (WGS) and an additional PCR analysis.
All S. haemolyticus isolates demonstrated multidrug resistance. Using WGS, various novel mec types and combinations of SCCmec types were found, including a new composite island [SCCmec type V (Vd)+SCC cad/ars/cop] comprising 30 % of the strains. SCCmec type V was identified in 23 % of the isolates. A combination of the mecA gene enclosed by two copies of IS431 and absence of the mecRI and ccr genes was identified in 11 strains. In total, mecA regulatory genes were absent in all SH isolates used in this study.
A high diversity of SCCmec elements with the prevalence of a new composite island was determined among MRSH strains. The structure of the composite island represented by MDR-SH strains in this study, in combination with the presence of a restriction-modification system type III, is described for the first time in this study. The presence of an 8 bp direct repeat (DR) and the sequences flanking the DR may support the integration of the mecA gene complex as a composite transposon (IS431-mecA-IS431) independently from recombinase genes.
金黄色葡萄球菌已成为一种具有高度抗药性的医疗相关病原体，尤其是对于新生儿重症监护病房的患者。本研究的目的是研究从儿科患者中分离出的多药耐药性金黄色葡萄球菌（MDR-SH）菌株的 SCCmec 类型。
从儿科患者中分离出 60 株金黄色葡萄球菌。使用纸片琼脂扩散和微量肉汤稀释法确定抗生素耐药模式。使用全基因组测序（WGS）和额外的 PCR 分析进行 SCCmec 分型。
所有金黄色葡萄球菌分离株均表现出多药耐药性。使用 WGS，发现了各种新型 mec 类型和 SCCmec 类型的组合，包括一种新的复合岛 [SCCmec 类型 V（Vd）+SCC cad/ars/cop]，占菌株的 30%。23%的分离株鉴定为 SCCmec 类型 V。在 11 株菌中，鉴定出 mecA 基因被两个 IS431 拷贝包围，且 mecRI 和 ccr 基因缺失。在本研究中使用的所有 SH 分离株中，mecA 调节基因均不存在。
在 MRSH 菌株中确定了 SCCmec 元件的高度多样性，并且存在新的复合岛。本研究首次描述了由 MDR-SH 菌株代表的复合岛结构，同时存在 III 型限制修饰系统。8bp 直接重复（DR）的存在和 DR 侧翼的序列可能支持 mecA 基因复合物作为复合转座子（IS431-mecA-IS431）的独立整合，而无需重组酶基因。
