Inactivation of enterotoxic and non-enterotoxic Staphylococcus aureus strains by high pressure treatments and evaluation of its impact on virulence factors

Effect of Photodynamic Therapy on the Virulence Factors of Staphylococcus aureus

“…et al, 2013 ) as a commensal microorganism, asymptomatically colonizing the host ( Bronner et al, 2004 ). Nevertheless, due to its invasiveness and taking advantage of host immune weaknesses, S. aureus is able to cause a wide spectrum of infections affecting different organs ( Bronner et al, 2004 ; Baptista et al, 2015 ), from infections of superficial lesions to intoxications and life threatening systemic conditions ( Bien et al, 2011 ). This opportunistic bacterium is a major human pathogen not only associated with community-acquired bacteremia but also nosocomial bacteremia ( Morikawa et al, 2001 ; Cheung et al, 2004 ; Bien et al, 2011 ), being readily able to acquire antibiotic resistance ( Morikawa et al, 2001 ).…”

“…et al, 2013 ). The extracellular components include the superantigen molecules such as the staphylococcal enterotoxins (SE), a family of a single chain proteins with small molecular-weight (24–30 kDa; Johnson et al, 1991 ; Baptista et al, 2015 ); the cytolytic β-hemolysin, the clotting factor coagulase, besides more exoenzymes as lipases and nucleases, in which their main function is to disrupt the host cells/tissue and the inactivation of host immune mechanisms of defense ( Costa A.R. et al, 2013 ).…”

Inactivation of Staphylococcus aureus by high pressure processing: An overview

“…The strains ATCC 6538 and 2153 MA (SEA) displayed an identical behavior being over the 10 consecutive HPP cycles opposite to the strain 2065 MA (SEA, SEG and SEI) which exhibited a continuous reduction in viability from the first to the fourth cycle, after which no surviving bacteria were detected (Baptista et al, 2015a). The enterotoxic strains (2153 MA and 2065 MA) with lower carotenoids content were easier inactivated by HPP treatments than the non-enterotoxic strain (ATCC 6538) (Baptista et al, 2015b). Hence, since S. aureus has the ability to adapt both phenotypically and genotypically, these fitness characteristic might be the reason why this species is highly resistant to HHP.…”

“…These differences, which can be more or less higher, can be the result of inherent characteristics of each strain such as the carotenoids produced by S. aureus which function as antioxidants, protecting S. aureus against oxidative stress and stabilizing the membrane during infection and pathogenesis (Chamberlain et al, 1991;Clauditz, Resch, Wieland, Peschel, & Götz, 2006;Mishra et al, 2011). Different S. aureus strains produce different quantities of carotenoids which seem to be important for the resistance to HPP, as observed on a number of studies in which authors were able to relate differences in carotenoid content with HPP resistance, i.e., strains with higher carotenoid content are more resistant than the ones with lower carotenoid content (Table 4) (Baptista et al, 2015a;Baptista et al, 2015b;Cebrián, Michiels, Mañas, & Condón, 2010). Other factors include the σ B factor (recognized as an important factor for the resistance of S. aureus to heat, pulsed electric fields treatments, as well as to chemical agents, controls the carotenoid production along with other detoxifying products such as catalases), as seen when comparing the Newton strain (which contains the σ B factor) with its isogenic mutant (without the σ B factor), being the shoulder duration (time during which the membrane is able to maintain its integrity and functionality) of the first one much higher than the last one (Cebrián et al, 2009;Cebrián et al, 2010).…”

“…Other factors include the σ B factor (recognized as an important factor for the resistance of S. aureus to heat, pulsed electric fields treatments, as well as to chemical agents, controls the carotenoid production along with other detoxifying products such as catalases), as seen when comparing the Newton strain (which contains the σ B factor) with its isogenic mutant (without the σ B factor), being the shoulder duration (time during which the membrane is able to maintain its integrity and functionality) of the first one much higher than the last one (Cebrián et al, 2009;Cebrián et al, 2010). Other factor appears to be the presence or absence of SE, since the strain ATCC 6538 (no SE) was more resistant than the strain 2153 MA (SEA) which was more resistant than the strain 2065 MA (SEA, SEG and SEI) (Baptista et al, 2015b). Furthermore, both ATCC 6538 and 2153 MA were able to withstand 10 HPP consecutive cycles while 2065 MA was only able to withstand 4 cycles (Baptista et al, 2015a).…”