Respiratory activity is essential for post-exponential-phase production of type 5 capsular polysaccharide by Staphylococcus aureus

Abstract

Capsule formation is believed to have a significant role in bacterial virulence. To examine the possible involvement of capsular polysaccharide (CP) from Staphylococcus aureus in the pathological mechanisms associated with staphylococcal infections, we investigated the influence of respiratory activity on type 5 CP production by S. aureus grown in the presence of various concentrations of dissolved oxygen or nitrate. The effects of several metabolic inhibitors (arsenite, cyanide, azide, trimethylamine N-oxide, 2-heptyl-4-hydroxyquinoline N-oxide, and 2,4-dinitrophenol) were also tested. The metabolism of the bacteria was estimated by measuring their reductive capacity and by monitoring the pH and concentrations of fermentation products. Type 5 CP was always produced by S. aureus during the exponential phase of growth under all culture conditions tested. In contrast, post-exponential-phase CP production appeared to be strictly dependent on the respiratory activity. Since post-exponential-phase CP production contributes at least two-thirds of the total CP obtained, the influence of S. aureus respiration on CP production might be of some importance in the process of infection.

Respiration metabolism of Group B Streptococcus is activated by environmental haem and quinone and contributes to virulence

“…Where previously examined, bacterial respiration was specifically inhibited by 2‐heptyl 4‐hydroxyquinoline N‐oxide (HQNO), a menaquinone analogue produced by Pseudomonas aeruginosa (Dassy and Fournier, 1996; Zhang et al ., 2002; Deziel et al ., 2004). Addition of 3 µM HQNO to aerated growth medium abolished effects of haemin and menaquinone on growth and pH; culture optical density and pH were essentially identical to those of aerated cultures without additions (A 600 = 2.9 ± 0.3; pH = 4.7 ± 0.1).…”

Identification of Staphylococcus aureus virulence genes in a murine model of bacteraemia using signature‐tagged mutagenesis

“…That mutations affecting the TCA cycle influence virulence was unexpected given that anaerobic growth of S. aureus is considered to be important during infection. However, respiratory activity is essential for capsule production during some stages of S. aureus growth in vitro (Dassy and Fournier, 1996), and capsule size can have significant effects on virulence (Lee et al, 1987). Therefore, it is possible that the mutations in genes for TCA enzymes have an indirect effect on virulence via capsule production.…”

MsaB and CodY Interact To Regulate Staphylococcus aureus Capsule in a Nutrient-Dependent Manner

“…S. aureus capsule polysaccharide has been shown to have a major role in bacterial virulence during infection by facilitating the survival of the pathogen inside the host, primarily via acting as an antiphagocytic factor to escape phagocytic uptake (19)(20)(21). As previously mentioned, in vitro capsule polysaccharide production is regulated in a growth phasedependent manner and is suppressed during the early and mid-exponential growth phases and activated during the late and post-exponential growth phases (22)(23)(24)(25). However, our previous data, as well as those from other groups, suggest that, in addition to growth phase, nutrient availability is also critical for the control of capsule production (8,22,(25)(26)(27).…”

“…These proteins include the two-component systems AirSR and KdpDE and the nutrient-or stress-sensing regulatory proteins CcpE, CodY, RbsR, SpoVG, and MsaB (25,(36)(37)(38)(39)(40)(41). The complexity of this region results in capsule polysaccharide being tightly regulated in a growth phase-dependent manner, where it is suppressed during the early and midexponential growth phases and activated during the late and post-exponential growth phases (22)(23)(24)(25).…”