Stress Response and Virulence of Heat-Stressed <i>Campylobacter jejuni</i>

Abstract

Thermotolerant Campylobacter spp. frequently cause bacterial gastroenteritis in humans commonly infected through the consumption of undercooked poultry meat. We examined Campylobacter jejuni heat-stress responses in vitro after exposure to 48°C and 55°C. The in vivo modulation of its pathogenicity was also investigated using BALB/c mice intravenously infected with stressed C. jejuni. Regardless of the bacterial growth phase, the culturability and viability of C. jejuni in vitro was reduced after exposure to 55°C. This correlated with the altered protein profile and decreased virulence properties observed in vivo. Heat stress at 48°C elicited the transition to more resistant bacterial forms, independent of morphological changes or the appearance of shorter spiral and coccoid cells. This treatment did not cause marked changes in bacterial virulence properties in vivo. These results indicated that the characteristics and pathogenicity of C. jejuni in response to heat stress are temperature dependent. Further studies on the responses of C. jejuni to stresses used during food processing, as well as the modulation of its virulence, are important for a better understanding of its contamination and infective cycle, and will, thus, contribute to improved safety in the food production chain.

Adhesion of Campylobacter jejuni Is Increased in Association with Foodborne Bacteria

“…Additionally, the metabolic by-products of one organism might serve to support the growth of another, while the adhesion of one species might provide ligands that promote the attachment of others [34]. The reasons for the increased adhesion of C. jejuni might also relate to their survival characteristics, their ability to response to stress conditions, which include oxidative stress using O 2 as an advantage for biofilm development, or their transition to more resistant cell forms [27,35]. Furthermore, the mechanism of C. jejuni biofilm formation might be a general response to adverse conditions that supports their high genetic diversity, which might contribute to longer term adaptation to varying environmental conditions, and the release of eDNA under biofilm conditions, which can promote the conditions that potentially serve for horizontal gene transfer [11,34].…”

Campylobacteriosis, Salmonellosis, Yersiniosis, and Listeriosis as Zoonotic Foodborne Diseases: A Review

“…Despite numerous studies on the molecular genetics of Campylobacter spp., their mechanisms of pathogenicity and virulence remain poorly understood [ 37 ]. Although the bacteria are considered to be susceptible to stress associated with environmental conditions, in the course of evolution, they were able to develop some complex mechanisms of survival and virulence, as presented in Table 1 [ 38 , 39 ].…”

Three Fusarium oxysporum mitogen‐activated protein kinases (MAPKs) have distinct and complementary roles in stress adaptation and cross‐kingdom pathogenicity

“…Heat shock responses are important for the virulence of bacterial and fungal pathogens of humans (Klancnik et al, 2014;Shapiro and Cowen, 2012). We hypothesized that resistance to high temperature should be a prerequisite for the ability of a cross-kingdom pathogen, such as F. oxysporum, to infect both plant and mammalian hosts.…”