The hyaluronate lyase of Staphylococcus aureus – a virulence factor?

Abstract

The hyaluronate lyase (HL) gene of Staphylococcus aureus 8325-4 (hysA) was inactivated in vitro with the insertion of the erythromycin determinant, ermC, from plasmid pE194. The hysA : : ermC mutation was introduced into S. aureus via a temperature-sensitive shuttle vector, where it underwent homologous recombination with the wild-type (w.t.) allele. The insertion of ermC in the chromosomal hysA locus was confirmed by Southern blot hybridization and the loss of HL activity was demonstrated macroscopically by a plate assay. The importance of HL for pathogenicity was assessed by comparing the virulence of the HL " mutant strain to that of the w.t. in an established mouse abscess model of S. aureus infection. A significantly higher cell recovery was obtained from lesions infected with the w.t. strain compared to the lesions infected with the HL " strain (P =0?01). Although the lesion areas from both groups were not significantly different (P=0?9) they were of different morphology. A colorimetric assay was used to measure HL activity from culture supernatants of the S. aureus 8325-4 strains w.t., WA250 (agr) and PC1839 (sar) grown in a chemically defined medium. HL activity reached a maximum in the w.t. strain during mid-exponential phase (t=5 h) and while it showed a 16-fold decrease in the agr mutant it increased 35-fold in the sar mutant background. These results strongly suggest that HL is a virulence factor which is important in the early stages of subcutaneous infections.

Hyaluronidase expression and biofilm involvement in Staphylococcus aureus UAMS-1 and its sarA, agr and sarA agr regulatory mutants

“…pyogenes parental strains were able to use HA as a sole source of carbon while hyaluronidase mutants were not. Others have also reported a role for hyaluronidase both in disease and in the acquisition of a suitable carbon and energy source (Cheng et al, 1995;Homer et al, 1997;Shain et al, 1996).In a previous study, hyaluronidase expression in S. aureus 8325-4 was shown to be activated by agr and repressed by sarA, as determined by hyaluronidase-specific activity in spent media (Makris et al, 2004). This study also showed that a mutation in the hyaluronidase gene resulted in reduced virulence in a mouse abscess model.…”

“…In a previous study, hyaluronidase expression in S. aureus 8325-4 was shown to be activated by agr and repressed by sarA, as determined by hyaluronidase-specific activity in spent media (Makris et al, 2004). This study also showed that a mutation in the hyaluronidase gene resulted in reduced virulence in a mouse abscess model.…”

“…intermedius was shown to involve hyaluronidase (Pecharki et al, 2008). Because sarA mutants of S. aureus are biofilm deficient (Beenken et al, 2003;Cassat et al, 2005;Valle et al, 2003) and express hyaluronidase at elevated levels (Jones et al, 2008;Makris et al, 2004), we postulated that the elevated levels of hyaluronidase observed in the sarA mutant background may contribute to the biofilm-negative phenotype.…”

“…This is a clinical strain isolated from a patient with osteomyelitis (Gillaspy et al, 1995) and does not have an rsbU mutation; it is thus safe to assume that this strain is not deficient in SigB activity (Cassat et al, 2006). In addition, because hyaluronidase has been shown to be involved in biofilm dispersal in Streptococcus intermedius (Pecharki et al, 2008) and sarA mutant strains of S. aureus are known to be deficient in biofilm formation (Beenken et al, 2003;Valle et al, 2003) as well as to express elevated amounts of hyaluronidase (Jones et al, 2008;Makris et al, 2004) we examined whether S. aureus hyaluronidase is involved in biofilm formation and/ or dispersal.…”

Glycoprotein analysis of porcine bronchoalveolar lavage fluid reveals potential biomarkers corresponding to resistance toActinobacillus pleuropneumoniaeinfection

“…(2009) 40:60hyaluronidase reflects increased hydrolysis of the extracellular matrix and enhanced permeability of the interstitial barrier for inflammatory cells. However, degradation of the interstitial barrier may also lead to a stronger infiltration of pathogens, possibly resulting in an increased immune response of the host [31]. Polymorphic neutrophil (PMN)-derived secretions of antibacterial enzymes such as serine proteases could cause the strong decline in the level of the elastase-sensitive protein SP-D which results in a decrease of the anti-inflammatory impact it has on the course of disease [9,48].…”