Abstract
BackgroundWe 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.ResultsVirulence 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.ConclusionThe 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.
Highlights
We describe the virulence factors of a methicillin-sensitive Staphylococcus aureus sequence type (ST) 45 strain, MCRF184, that caused severe necrotizing fasciitis in a 72-year-old diabetic male
The ability of S. aureus to colonize and infect humans comes from a large arsenal of virulence genes including genes for proteins to attach to host tissue, tissue-degrading enzymes, leukocidins, antibiotic-resistance, pyrogenic toxins, and immunomodulating proteins [1]
Overview of antimicrobial resistance and virulence gene content MCRF184 is a methicillin-susceptible strain that belongs to sequence type (ST) 45 and spa type t917
Summary
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. A number of S. aureus genomes have been sequenced to identify potential new virulence genes or novel combinations of known virulence genes [2]. These studies have led to the identification of new genomic islands and genetic elements, which harbor known and putative toxins, phenol-soluble modulins, and accessory genes to virulence [3,4,5,6]. We describe here the virulence traits of MCRF184, a methicillin-sensitive, ST45 strain that caused a debilitating necrotizing fasciitis in a diabetic man, necessitating the amputation of the patient’s leg to save his life
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
