Carrera-Salinas Anna, González-Díaz Aida, Vázquez-Sánchez Daniel Antonio, Camoez Mariana, Niubó Jordi, Càmara Jordi, Ardanuy Carmen, Martí Sara, Domínguez M Ángeles
Department of Microbiology, Hospital Universitari de Bellvitge, Institut D'Investigació Biomèdica de Bellvitge (IDIBELL), Barcelona, Spain.
Department of Microbiology, Hospital Universitari de Bellvitge, Institut D'Investigació Biomèdica de Bellvitge (IDIBELL), Barcelona, Spain; Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.
Res Microbiol. 2022 Mar-Apr;173(3):103921. doi: 10.1016/j.resmic.2022.103921. Epub 2022 Jan 26.
Methicillin-resistant Staphylococcus aureus (MRSA) may persist for long periods due to biofilm formation. The objective of this study was to describe biofilm formation in association with the presence of S. aureus surface protein G (sasG) and its allelic variants in MRSA bacteraemia isolates from endemic (CC5, CC8, CC22) and sporadic clones in Spain (2008-2015). Crystal violet staining was used to assess biofilm formation; DNA microarray, RT-qPCR, and long-read whole genome sequencing were applied to determine the presence, expression and structure of sasG, respectively. The endemic CC5 and CC8 clones produced more biofilm than the sporadic clones; these endemic clones carried sasG allelic variant 1. Otherwise, sporadic clones, with less biofilm formation, showed either an absence of sasG (65%) or the presence of allelic variant 2 (35%). Variants 1 and 2 differed in the expression of sasG (1.56 ± 1.20 and 0.37 ± 0.32, respectively). The analysis of a large cohort of closed S. aureus genomes available on the NCBI database confirmed the distribution of the two allelic variants with low amino acid identity (68.1%) among endemic and sporadic clones. SasG variant 1 present in the major CC5 and CC8 clones was correlated with increased biofilm formation and may represent an important virulence determinant.
耐甲氧西林金黄色葡萄球菌（MRSA）可能因生物膜形成而长期持续存在。本研究的目的是描述在西班牙（2008 - 2015年）流行克隆（CC5、CC8、CC22）和散发克隆的MRSA菌血症分离株中，与金黄色葡萄球菌表面蛋白G（sasG）及其等位基因变体的存在相关的生物膜形成情况。采用结晶紫染色评估生物膜形成；分别应用DNA微阵列、RT-qPCR和长读长全基因组测序来确定sasG的存在、表达和结构。流行的CC5和CC8克隆比散发克隆产生更多的生物膜；这些流行克隆携带sasG等位基因变体1。否则，生物膜形成较少的散发克隆要么不存在sasG（65%），要么存在等位基因变体2（35%）。变体1和2在sasG的表达上有所不同（分别为1.56±1.20和0.37±0.32）。对NCBI数据库中大量可用的封闭金黄色葡萄球菌基因组进行分析，证实了这两种等位基因变体在流行克隆和散发克隆中的分布，其氨基酸同一性较低（68.1%）。主要CC5和CC8克隆中存在的SasG变体1与生物膜形成增加相关，可能是一个重要的毒力决定因素。
