全球进化枝中耐甲氧西林巨大球菌的种群结构、抗菌药物耐药性、毒力因子和形态特征。
Characteristics of population structure, antimicrobial resistance, virulence factors, and morphology of methicillin-resistant Macrococcus caseolyticus in global clades.
机构信息
Pasteurien College, Suzhou Medical College, Soochow University, Suzhou, Jiangsu, China.
出版信息
BMC Microbiol. 2022 Nov 5;22(1):266. doi: 10.1186/s12866-022-02679-8.
Macrococcus caseolyticus is an opportunistic pathogen that is frequently isolated from dairy products and veterinary infections. Recent studies have reported the possibility of methicillin resistance that be transferred among staphylococcal species in foods. The present study examined the population structure, antimicrobial resistance, virulence factors, and morphology of methicillin-resistant M. caseolyticus by investigation of 94 genomes derived from both isolates in beef (n = 7) and pork (n = 2) at Shanghai and those deposited in public domain (n = 85). Phylogenetically, M. caseolyticus were divided into four clades, which each consisted of genomes isolated from continent of European countries (82.4%, n = 78), Asian countries (11.3%, n = 10), United States (4.1%, n = 4), Australia (1%, n = 1), and Sudan (1%, n = 1). The M. caseolyticus isolated from present study formed a genetically distinguished clade, which was characterized by novel alleles in the traditional 7-gene MLST scheme. Furthermore, we identified 24 AMR genes that were associated with 10 classes of antimicrobial agents in M. caseolyticus. Most AMR genes were carried by dominant plasmids such as rep7a, rep22 and repUS56. The genomes in the global clades carried significantly less AMR genes (p < 0.05) and more virulence factors (p < 0.001) than present clade. Virulence factors were detected in methicillin resistant M. caseolyticus including genes coding hemolysin, adherence, biofilm formation, exotoxin, and capsule that associated to human health and infection. Finally, as the close relative of the genus Staphylococcus, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed for morphological comparison that M. caseolyticus has a larger diameter and thicker cell wall compared with S. aureus ATCC 25,923. Taken together, our study suggested that M. caseolyticus mediating divergent antimicrobial resistance and virulence factors could serve as the vector for methicillin resistance habitats in foodborne microorganisms.
巨大微球菌是一种机会致病菌，常从乳制品和兽医感染中分离出来。最近的研究报告称，在食品中，葡萄球菌属种间可能存在耐甲氧西林的情况。本研究通过对上海牛肉（n=7）和猪肉（n=2）来源的 94 个分离株基因组和公共领域（n=85）的分离株进行调查，研究了耐甲氧西林巨大微球菌的种群结构、抗菌药物耐药性、毒力因子和形态，这些分离株从欧洲国家（82.4%，n=78）、亚洲国家（11.3%，n=10）、美国（4.1%，n=4）、澳大利亚（1%，n=1）和苏丹（1%，n=1）。巨大微球菌分为四个进化枝，每个进化枝都由来自欧洲国家的基因组组成（82.4%，n=78），亚洲国家（11.3%，n=10），美国（4.1%，n=4），澳大利亚（1%，n=1）和苏丹（1%，n=1）。本研究中分离的巨大微球菌形成了一个遗传上独特的进化枝，其特点是在传统的 7 基因 MLST 方案中有新的等位基因。此外，我们在巨大微球菌中鉴定了 24 个与 10 类抗菌药物相关的 AMR 基因。大多数 AMR 基因位于 dominant plasmids 上，如 rep7a、rep22 和 repUS56。全球进化枝的基因组携带的 AMR 基因明显较少（p < 0.05），携带的毒力因子明显较多（p < 0.001）。在耐甲氧西林巨大微球菌中检测到了包括编码溶血素、黏附、生物膜形成、外毒素和荚膜的基因，这些基因与人类健康和感染有关。最后，由于与葡萄球菌属密切相关，我们进行了扫描电子显微镜（SEM）和透射电子显微镜（TEM）检查，结果表明巨大微球菌的直径较大，细胞壁较厚，与金黄色葡萄球菌 ATCC 25923 相比。综上所述，我们的研究表明，介导不同抗菌药物耐药性和毒力因子的巨大微球菌可能是食源微生物中甲氧西林耐药性栖息地的媒介。
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