Departamento de Fisiologia e Patologia, Universidade Federal da Paraíba, Campus I - Cidade Universitaria, João Pessoa, PB, 58051-900, Brazil.
Curso de Biomedicina, Centro Universitário Metodista IPA, Porto Alegre, Brazil.
Braz J Microbiol. 2020 Sep;51(3):1071-1078. doi: 10.1007/s42770-020-00278-1. Epub 2020 Apr 23.
Coagulase-negative staphylococci (CoNS) are frequently isolated in clinical specimens and are important reservoirs of resistance genes. In 2019, the Brazilian government set the BrCAST/EUCAST (Brazilian Committee on Antimicrobial Susceptibility Testing) guidelines as the national standard, resulting in changes in the interpretation of CoNS susceptibility tests. From outpatients, disk-diffusion susceptibility of 65 CoNS cultures were evaluated and compared using classification criteria from both CLSI and BrCAST/EUCAST. The isolates were identified using matrix assisted laser desorption ionization-time of flight (MALDI-TOF), and the presence of the mecA gene was determined. The most prevalent species were Staphylococcus saprophyticus (32.3%), S. haemolyticus (18.5%), and S. epidermidis (9.2%). Almost perfect agreement was seen between the guidelines, except concerning oxacillin and gentamicin, and the prevalence of multidrug resistant isolates increased with the use of BrCAST/EUCAST. Of all, 15 (23.1%) isolates, mainly S. epidermidis and S. haemolyticus, were positive for the mecA gene, and only three were detected when using CLSI or BrCAST/EUCAST disk-diffusion screening. This, using either guideline, could reveal the difficulty of determining oxacillin resistance. Using warning zones or molecular methods might well be indicated for CoNS. In conclusion, adoption of the BrCAST/EUCAST guidelines will result in certain artificial changes in epidemiological susceptibility profiles, and clinicians and institutions should be aware of the possible implications.
凝固酶阴性葡萄球菌（CoNS）经常从临床标本中分离出来，是耐药基因的重要储存库。2019 年，巴西政府将 BrCAST/EUCAST（巴西抗菌药物敏感性测试委员会）指南作为国家标准，导致 CoNS 药敏试验的解释发生变化。从门诊患者中评估了 65 株 CoNS 培养物的纸片扩散药敏性，并使用 CLSI 和 BrCAST/EUCAST 的分类标准进行了比较。使用基质辅助激光解吸电离飞行时间（MALDI-TOF）对分离株进行鉴定，并确定 mecA 基因的存在。最常见的物种是腐生葡萄球菌（32.3%）、溶血葡萄球菌（18.5%）和表皮葡萄球菌（9.2%）。除了对苯唑西林和庆大霉素的药敏试验外，两种指南之间几乎完全一致，而且随着 BrCAST/EUCAST 的使用，多药耐药分离株的流行率增加。在所有分离株中，有 15 株（23.1%），主要是表皮葡萄球菌和溶血葡萄球菌，mecA 基因阳性，而使用 CLSI 或 BrCAST/EUCAST 纸片扩散筛选时，仅检测到 3 株。这表明，使用任何一种指南都可能难以确定苯唑西林的耐药性。对于 CoNS，使用警告区或分子方法可能是必要的。总之，采用 BrCAST/EUCAST 指南将导致流行病学药敏谱的某些人为变化，临床医生和机构应意识到可能的影响。
