一株金黄色葡萄球菌 45 型序列株（MCRF184）的毒力因子图谱。

Virulence factor landscape of a Staphylococcus aureus sequence type 45 strain, MCRF184.

机构信息

Department of Internal Medicine & Pediatrics, University at Buffalo, Buffalo, New York, USA.

Department of Chemistry & Biochemistry, University of Oklahoma, Norman, OK, USA.

出版信息

BMC Genomics. 2019 Feb 8;20(1):123. doi: 10.1186/s12864-018-5394-2.

BACKGROUND

We describe the virulence factors of a methicillin-sensitive Staphylococcus aureus sequence type (ST) 45 strain, MCRF184, (spa type t917), that caused severe necrotizing fasciitis in a 72-year-old diabetic male. The genome of MCRF184 possesses three genomic islands: a relatively large type III νSaα with 42 open reading frames (ORFs) that includes superantigen- and lipoprotein-like genes, a truncated νSaβ that consists mostly of the enterotoxin gene cluster (egc), and a νSaγ island with 18 ORFs including α-toxin. Additionally, the genome has two phage-related regions: phage φSa3 with three genes of the immune evasion cluster (IEC), and an incomplete phage that is distinct from other S. aureus phages. Finally, the region between orfX and orfY harbors a putative efflux pump, acetyltransferase, regulators, and mobilization genes instead of genes of SCCmec.

RESULTS

Virulence factors included phenol soluble modulins (PSMs) α1 through α4 and PSMs β1 and β2. Ten ORFs identified in MCRF184 had not been reported in previously sequenced S. aureus strains.

CONCLUSION

The dire clinical outcome in the patient and the described virulence factors all suggest that MCRF184, a ST45 strain is a highly virulent strain of S. aureus.

背景

我们描述了一株耐甲氧西林金黄色葡萄球菌（MSSA）序列型（ST）45 菌株 MCRF184 的毒力因子，该菌株 spa 型为 t917，导致一名 72 岁糖尿病男性发生严重坏死性筋膜炎。MCRF184 的基因组包含三个基因组岛：一个相对较大的 III 型 νSaα，含有 42 个开放阅读框（ORFs），包括超抗原和脂蛋白样基因；一个截断的 νSaβ，主要由肠毒素基因簇（egc）组成；以及一个包含 18 个 ORFs 的 νSaγ 岛，包括α-毒素。此外，基因组还包含两个与噬菌体相关的区域：带有三个免疫逃逸簇（IEC）基因的噬菌体 φSa3 和一个不同于其他金黄色葡萄球菌噬菌体的不完整噬菌体。最后，orfX 和 orfY 之间的区域携带一个假定的外排泵、乙酰转移酶、调节剂和移动基因，而不是 SCCmec 的基因。