Staphylococcus aureus In Vitro Secretion of Alpha Toxin (hla) Correlates with the Affiliation to Clonal Complexes

Abstract

The alpha toxin of Staphylococcus aureus is a pore forming toxin that penetrates host cell membranes causing osmotic swelling, rupture, lysis and subsequently cell death. Haemolysin alpha is toxic to a wide range of different mammalian cells; i.e., neurotoxic, dermonecrotic, haemolytic, and it can cause lethality in a wide variety of animals. In this study, the in vitro alpha toxin production of 648 previously genotyped isolates of S. aureus was measured quantitatively using antibody microarrays. Isolates originated from medical and veterinary settings and were selected in order to represent diverse clonal complexes and defined clinical conditions. Generally, the production of alpha toxin in vitro is related to the clonal complex affiliation. For clonal complexes CC22, CC30, CC45, CC479, CC705 and others, invariably no alpha toxin production was noted under the given in vitro conditions, while others, such as CC1, CC5, CC8, CC15 or CC96 secreted variable or high levels of alpha toxin. There was no correlation between alpha toxin yield and clinical course of the disease, or between alpha toxin yield and host species.

Unveiling the fate of adhering bacteria to antimicrobial surfaces: expression of resistance-associated genes and macrophage-mediated phagocytosis

“…Finally, the expression profile of known virulence related genes, namely clpP and hla, was also addressed. Alpha-hemolysin, also called alpha toxin, encoded by hla gene, is a protein which insertion into host cell membranes results in their lysis [49]. The prote-olytic subunit of the ATP-dependent Clp protease (ClpP) is encoded by ClpP gene.…”

High persister cell formation by clinical Staphylococcus aureus strains belonging to clonal complex 30

“…For example, the strikingly enhanced expression of protein A (spa) is speculated to diminish the host immune response; the significantly lowered expression of multiple members of the pyrimidine biosynthesis pathway confers comparable characteristics as small colony variants [15]. Moreover, CC30 isolates are attenuated in key virulence factors due to accumulated SNPs in genes encoding alpha toxin (hla), phenol-soluble modulin (PSMα3) and accessory gene regulator C (agrC) [30,31]. The data presented in the current study suggest that CC30 isolates in addition have an enhanced ability to form persisters under in vitro conditions compared with other major CCs in response to ciprofloxacin.…”

Clonal diversity of methicillin-sensitive Staphylococcus aureus from South Australian wallabies

“…To date, CC692 has been isolated exclusively from various birds and, as such, to the best of our knowledge, this represents the first report of CC692 from any mammalian species [4]. For CC49-MSSA, only a few human and veterinary cases have been reported from Western Europe.…”