The effects of subinhibitory concentrations of costus oil on virulence factor production in Staphylococcus aureus

Abstract

Aim: To determine the antimicrobial activity of costus (Saussurea lappa) oil against Staphylococcus aureus, and to evaluate the influence of subinhibitory concentrations of costus oil on virulence‐related exoprotein production in staph. aureus. Methods and Results: Minimal inhibitory concentrations (MICs) were determined using a broth microdilution method, and the MICs of costus oil against 32 Staph. aureus strains ranged from 0.15 to 0.6 μl ml−1. The MIC50 and MIC90 were 0.3 and 0.6 μl ml−1, respectively. Western blot, haemolytic, tumour necrosis factor (TNF) release and real‐time RT‐PCR assays were performed to evaluate the effects of subinhibitory concentrations of costus oil on virulence‐associated exoprotein production in Staph. aureus. The data presented here show that costus oil dose dependently decreased the production of α‐toxin, toxic shock syndrome toxin 1 (TSST‐1) and enterotoxins A and B in both methicillin‐sensitive Staph. aureus (MSSA) and methicillin‐resistant Staph. aureus (MRSA). Conclusion: Costus oil has potent antimicrobial activity against Staph. aureus, and the production of α‐toxin, TSST‐1 and enterotoxins A and B in Staph. aureus was decreased by costus oil. Significance and Impact of the Study: The data suggest that costus oil may deserve further investigation for its potential therapeutic value in treating Staph. aureus infections. Furthermore, costus oil could be rationally applied in food products as a novel food preservative both to inhibit the growth of Staph. aureus and to repress the production of exotoxins, particularly staphylococcal enterotoxins.

The Olive Compound 4‐Hydroxytyrosol Inactivates Staphylococcus aureus Bacteria and Staphylococcal Enterotoxin A (SEA)

“…Because the toxin is present in contaminated foods and exerts adverse effects on the gastrointestinal tract, there is a need to find food‐compatible safe conditions to inactivate it. Efforts to inhibit the toxin or its release from S. aureus include the use of electrolyzed water (Suzuki and others 2002), high pressure and heat (Margosch and others 2005), radiation and pulsed electric fields (Walkling‐Ribeiro and others 2008), condensed tannins (Choi and others 2007) and other plant extracts (Ifesan and Voravuthlkunchai 2009; Carlos and others 2010), peptides (Wang and others 2008), phenolic compounds (Rúa and others 2010), licochalcone A (Qiu and others 2010), essential oils (Friedman and others 2004; Nuñez and others 2007; de Souza and others 2010; Parsaeimehr and others 2010; Qiu and others 2011), and toxin‐specific antibodies (Larkin and others 2010). …”

Effect of Subinhibitory Concentrations of Chlorogenic Acid on Reducing the Virulence Factor Production byStaphylococcus aureus

“…Several studies have reported that plant extracts, different from mechanisms used by antibiotics, can reduce production of exotoxins at subinhibitory concentrations (Xiang et al, 2010;Leng et al, 2011;Qiu et al, 2012). Qiu et al (2011b) observed that costus oil decreased the production of a-toxin, TSST-1, and enterotoxins A and B in S. aureus. Qiu et al (2010a) reported that subinhibitory concentrations of thymol reduced enterotoxins A and B and a-hemolysin production in S. aureus.…”

“…aureus ATCC 29213 was incubated with and without CA in LB broth for 12 h, then the total RNAs from the bacterial cultures was extracted as described by Qiu et al (2011b) using an RNApure Bacteria Kit (Tiangen, Beijing, China). RNA was reverse transcribed into cDNA using the Takara PrimeScript TM RT reagent kit (Perfect Real Time) (Takara, Kyoto, Japan) according to the manufacturer's instructions.…”

Food Compounds Inhibit Staphylococcus Aureus Bacteria and the Toxicity of Staphylococcus Enterotoxin A (SEA) Associated with Atopic Dermatitis

“…Because SEA is present in contaminated foods and exerts adverse effects on the gastrointestinal tract, there is a need to find food-compatible safe conditions to inactivate it. Efforts to inhibit the toxin or its release from S. aureus include the use of electrolyzed water (Suzuki et al, 2002), high pressure and heat (Margosch et al, 2005), radiation and pulsed electric fields (Walkling-Ribeiro et al, 2008), condensed tannins (Choi et al, 2007) and other plant extracts (Carlos et al, 2010;Ifesan & Voravuthlkunchai, 2009), peptides (Wang et al, www.intechopen.com Atopic Dermatitis -Disease Etiology and Clinical Management 388 2008), phenolic compounds (Rúa et al, 2010), licochalcone A (Qiu et al, 2010), essential oils (de Souza et al, 2010;Friedman et al, 2004a;Nuñez et al, 2007;Parsaeimehr et al, 2010;Qiu et al, 2011), and toxin-specific antibodies (Larkin et al, 2010). The objective of our research effort is to discover food-compatible ways to inhibit or inactivate both the pathogen and the toxin.…”