Ceballos Sara, Aspiroz Carmen, Ruiz-Ripa Laura, Azcona-Gutierrez José Manuel, López-Cerero Lorena, López-Calleja Ana Isabel, Álvarez Ledicia, Gomáriz María, Fernández Marina, Torres Carmen
Area Bioquímica y Biología Molecular, Universidad de La Rioja, Logroño, Spain.
Servicio de Microbiología, Hospital Royo Villanova, Zaragoza, Spain.
Enferm Infecc Microbiol Clin (Engl Ed). 2019 Oct;37(8):509-513. doi: 10.1016/j.eimc.2019.01.015. Epub 2019 Mar 14.
Methicillin-resistant Staphylococcus aureus (MRSA) is considered a major cause of healthcare-associated (HA) and community-acquired (CA) infections. Considering non-β-lactam susceptibility as a potential marker for mecC-MRSA and CA-MRSA, the aim of this study was to determine the frequency and the associated genetic lineages of non-beta-lactam-antibiotic susceptible MRSA (NBLS-MRSA) strains in a multicenter study in Spain.
A collection of 45 NBLS-MRSA strains recovered in the period from January to June 2016 from 12 Spanish hospitals was analyzed. Molecular typing through spa-type characterization, agr group and multi-locus-sequence typing was performed. Methicillin-resistant genes (mecA and mecC) as well as immune evasion cluster (scn-chp-sak-sea-sep, considering scn gene as the marker of IEC system) and Panton-Valentine leukocidin (PVL) genes were determined with PCR/sequencing.
The NBLS-MRSA phenotype was uncommon in the 12 hospitals analyzed (NBLS-MRSA/MRSA frequency: 0.3%-7.7%). All strains contained the mecA gene (and none contained mecC). Twenty-two different spa-types were detected among NBLS-MRSA strains, with spa-t008/agr-I the most prevalent (27%). The main clonal complexes were (CC/%): CC8/42.2%, CC5/33.3% and CC30/4.4%, with ST8 and ST5 as the main sequence types. The PVL toxin was present in 38% of strains (with spa-types t008, t024, t019, t044, t068, t318 and t3060). The IEC genes were detected in 78% of strains: IEC type-B (n=17), type-F (n=16), type-A (n=1) and type-E (n=1); 10 MRSA isolates were scn-negative.
The NBLS-MRSA phenotype is uncommon in the analyzed hospitals; although no mecC-positive strains were detected, it could be a good marker for MRSA PVL-positive isolates (38%), frequently associated with CA-MRSA infections.
耐甲氧西林金黄色葡萄球菌（MRSA）被认为是医疗保健相关（HA）感染和社区获得性（CA）感染的主要原因。考虑到对非β-内酰胺类药物的敏感性作为mecC-MRSA和CA-MRSA的潜在标志物，本研究的目的是在西班牙的一项多中心研究中确定对非β-内酰胺类抗生素敏感的MRSA（NBLS-MRSA）菌株的频率及其相关的基因谱系。
分析了2016年1月至6月期间从西班牙12家医院收集的45株NBLS-MRSA菌株。通过spa型特征、agr组和多位点序列分型进行分子分型。采用PCR/测序法检测耐甲氧西林基因（mecA和mecC）以及免疫逃避簇（scn-chp-sak-sea-sep，以scn基因作为IEC系统的标志物）和杀白细胞素（PVL）基因。
在分析的12家医院中，NBLS-MRSA表型并不常见（NBLS-MRSA/MRSA频率：0.3%-7.7%）。所有菌株均含有mecA基因（无一含有mecC）。在NBLS-MRSA菌株中检测到22种不同的spa型，其中spa-t008/agr-I最为常见（27%）。主要的克隆复合体为（CC/%）：CC8/42.2%、CC5/33.3%和CC30/4.4%，主要序列类型为ST8和ST5。38%的菌株中存在PVL毒素（spa型为t008、t024、t019、t044、t068、t318和t3060）。78%的菌株中检测到IEC基因：IEC B型（n=17）、F型（n=16）、A型（n=1）和E型（n=1）；10株MRSA分离株scn呈阴性。
在分析的医院中，NBLS-MRSA表型并不常见；尽管未检测到mecC阳性菌株，但它可能是MRSA PVL阳性分离株（38%）的良好标志物，这些分离株常与CA-MRSA感染相关。
