Staphylococcus aureus virulence genes identified by bursa aurealis mutagenesis and nematode killing

Abstract

Staphylococcus aureus is the leading cause of wound and hospitalacquired infections worldwide. The emergence of S. aureus strains with resistance to multiple antibiotics requires the identification of bacterial virulence genes and the development of novel therapeutic strategies. Herein, bursa aurealis, a mariner-based transposon, was used for random mutagenesis and for the isolation of 10,325 S. aureus variants with defined insertion sites. By screening for loss-of-function mutants in a Caenorhabditis elegans killing assay, 71 S. aureus virulence genes were identified. Some of these genes are also required for S. aureus abscess formation in a murine infection model. transposon ͉ Caenorhabditis elegans

EsxA and EsxB are secreted by an ESAT-6-like system that is required for the pathogenesis ofStaphylococcus aureusinfections

“…essABC, esaAB, and esxB mutants were obtained from the Phoenix (⌽N⌶) library (20) (Table 1). Each Phoenix isolate is a derivative of the clinical isolate Newman (21) and carries the transposon bursa aurealis at a site on the chromosome that has been determined by DNA sequencing (20) and compared to S. aureus Mu50 genomic sequence (22). All bursa aurealis insertions were transduced into wild-type S. aureus Newman by using bacteriophage 85 (23).…”

“…All Phoenix strains (⌽N⌶) are isogenic to S. aureus Newman (21) and are part of our laboratory collection (20). In strain esxA24, a stop codon replaces the coding codon at position 8.…”

“…We wondered whether the factors encoded by the S. aureus ess cluster regulate production or promote secretion of EsxA and EsxB. Previous work from our laboratory generated the Phoenix (⌽N⌶) library, a collection of bursa aurealis insertion mutants in S. aureus strain Newman that have been mapped by inverted PCR and DNA sequencing (20). S. aureus strain Newman variants ⌽N⌶09349, ⌽N⌶03742, ⌽N⌶13152, ⌽N⌶02411, ⌽N⌶04464, and ⌽N⌶07912 carry bursa aurealis insertions in esaA, essA, esaB, essB, essC, or esxB, respectively (Table 1 and Fig.…”

Host defenses againstStaphylococcus aureusinfection require recognition of bacterial lipoproteins

“…Chloramphenicol and erythromycin were used at 10 mg͞liter, and ampicillin was used at 100 mg͞liter. lgt, lsp, nuc, spa, and gmpC mutants were obtained from the Phoenix (⌽N⌶) library (16). Each Phoenix isolate is a derivative of the clinical isolate Newman (16,37).…”

The arl locus positively regulates Staphylococcus aureus type 5 capsule via an mgrA-dependent pathway

“…These studies provide compelling evidence that CP5 and CP8 are important antiphagocytic virulence factors (for reviews see Lee & Lee, 2006;O'Riordan & Lee, 2004). Additionally, staphylococcal capsule was recently implicated as one of the few extracellular factors required for virulence in Caenorhabditis elegans (Bae et al, 2004).…”