Muzy Dias Aline Pecanha, Guimarães Lorrayne Cardoso, V Petrucci Livia B D, Z Pinheiro Jéssica A, Pinheiro Marcos Gabriel, Silva Felipe Rodrigues E, Póvoa Helvécio C C, Aguiar-Alves Fábio
Department of Basic Science, Fluminense Federal University, Nova Friburgo; Department of Pharmacy, University Laboratory Rodolpho Albino, Molecular Epidemiology Laboratory; Program of Pathology and Program of Microbiology and Parasitology, Fluminense Federal University, Niterói, RJ-, Brazil.
Department of Medical Microbiology, Nosocomial Laboratory, Paulo de Goés Microbiology Institute, Rio de Janeiro Federal University, Rio de Janeiro, Brazil.
Indian J Med Microbiol. 2020 Apr-Jun;38(2):192-199. doi: 10.4103/ijmm.IJMM_20_157.
Nosocomial infections arise from many microorganisms, including Staphylococcus aureus.
The aim of this study is to determine the molecular epidemiology of circulating methicillin-resistant S. aureus (MRSA) clones among patients attending community and health-care facilities in Nova Friburgo, RJ, Brazil.
A total of 1002 nasal swab samples were collected from May 2010 to September 2015. S. aureus isolates were identified through phenotypic tests, submitted to antimicrobial susceptibility tests and genotypic analysis to detect mecA, panton-valentine leucocidin (PVL) genes, SCCmec, SPA and multilocus sequencing typing (MLST) typing.
We identified 294 (29.3%) isolates as S. aureus and 91 (9.1%) as MRSA. A total of 17 isolates did not present a correlation between phenotypic and genotypic resistance profiles. Among MRSA isolates, 17 (18.7%) carried PVL genes. A total of 20 different SPA types were determined, being grouped by MLST into eight different sequence types. ST5/t002 was the most prevalent genotype found among these isolates.
There is a gradual colonisation shift happening in the infection pattern by S. aureus in Brazil. The Brazilian Epidemic Clone (ST239-SCCmec IIIa-PVL-) seems to be substituted by isolates from different clonal complexes, such as ST5, ST8 and ST30. The non-correlation between phenotypic/genotypic resistance profile observed in some isolates suggests the presence of other methicillin resistance mechanisms different from mecA presence or a difference in the nucleotide sequence, which prevents the primers to identify the specific region during polymerase chain reaction reactions. MRSA identification should be based on phenotypic and genotypic testing to ensure the various types of resistance mechanisms.
医院感染由多种微生物引起，包括金黄色葡萄球菌。
本研究旨在确定巴西里约热内卢新弗里堡社区和医疗机构患者中循环的耐甲氧西林金黄色葡萄球菌（MRSA）克隆的分子流行病学。
2010年5月至2015年9月共收集了1002份鼻拭子样本。通过表型试验鉴定金黄色葡萄球菌分离株，进行抗菌药敏试验和基因分析以检测mecA、杀白细胞素（PVL）基因、葡萄球菌染色体盒式Mec（SCCmec）、葡萄球菌蛋白A（SPA）和多位点测序分型（MLST）分型。
我们鉴定出294株（29.3%）为金黄色葡萄球菌，91株（9.1%）为MRSA。共有17株分离株的表型和基因型耐药谱之间不存在相关性。在MRSA分离株中，17株（18.7%）携带PVL基因。共确定了20种不同的SPA类型，通过MLST分为8种不同的序列类型。ST5/t002是这些分离株中最常见的基因型。
巴西金黄色葡萄球菌感染模式正在发生逐渐的定植转移。巴西流行克隆（ST239-SCCmec IIIa-PVL-）似乎被来自不同克隆复合体的分离株所取代，如ST5、ST8和ST30。在一些分离株中观察到的表型/基因型耐药谱之间的不相关性表明存在不同于mecA存在的其他耐甲氧西林耐药机制，或者核苷酸序列存在差异，这阻止了引物在聚合酶链反应中识别特定区域。MRSA的鉴定应基于表型和基因型检测，以确保检测到各种类型的耐药机制。
