Arcobacter butzleri and intestinal colonization

Pinosylvin: A Multifunctional Stilbenoid with Antimicrobial, Antioxidant, and Anti-Inflammatory Potential

Stilbenoids are a category of plant compounds exhibiting notable health-related benefits. After resveratrol, perhaps the most well-known stilbenoid is pinosylvin, a major phytochemical constituent of most plants characterised by the pine spines among others. Pinosylvin and its derivatives have been found to exert potent antibacterial and antifungal effects, while their antiparasitic and antiviral properties are still a subject of ongoing research. The antioxidant properties of pinosylvin are mostly based on its scavenging of free radicals, inhibition of iNOS and protein kinase C, and promotion of HO-1 expression. Its anti-inflammatory properties are based on a variety of mechanisms, such as COX-2 inhibition, NF-κB and TRPA1 activation inhibition, and reduction in IL-6 levels. Its anticancer properties are partly associated with its antioxidant and anti-inflammatory potential, although a number of other mechanisms are described, such as apoptosis induction and matrix metalloproteinase inhibition. A couple of experiments have also suggested a neuroprotective potential. A multitude of ethnomedical and ethnobotanical effects of pinosylvin-containing plants are reported, like antimicrobial, antioxidant, anti-inflammatory, hepatoprotective, and prokinetic actions; many of these are corroborated by recent research. The advent of novel methods of artificial pinosylvin synthesis may facilitate its mass production and adoption as a medical compound. Finally, pinosylvin may be a tool in promoting environmentally friendly pesticide and insecticide policies and be used in land remediation schemes.

Human Toll-like receptor activation by pathogenic Arcobacter species

The increase of Arcobacter spp. infection cases in humans, coupled with varying symptomatology, highlights the need to study the virulence mechanisms of these bacteria. Arcobacter butzleri can induce the release of several proinflammatory cytokines in human monocytic-derived macrophages, but the mechanism used to achieve this is still unclear. Therefore, we aimed to investigate the human innate immune response triggered by pathogenic Arcobacter spp., by studying the activation of the human Toll-like receptors (TLRs). Arcobacter skirrowii was the only species that showed the ability to activate all tested TLRs. Arcobacter cryaerophilus demonstrated to be able to activate TLR1/2, TLR4, and TLR2/6. A. butzleri hardly activated the TLRs, only TLR2/6 and TLR1/2 to a small extent. While all the Arcobacter species tested possess flagellum, as shown by motility assays and electron microscopy, only the flagellum of A. skirrowii was able to activate TLR5. The alignment of the flagellin amino acid data revealed that A. skirrowii shares a greater number of crucial amino acids for TLR5 recognition with the FliC of Salmonella than the other Arcobacter species, which might explain why A. skirrowii activates TLR5. Our results demonstrated that the activation of the different TLRs is Arcobacter species dependent, and there might be a correlation between the activation of the TLRs and the pathogenicity of the Arcobacter species.

Foodborne and waterborne Arcobacter species exhibit a high virulent activity in Caco-2

Infection mechanisms of Arcobacter remain uncertain. This study aimed to determine whether 65 food and waterborne isolates of at least six species were able to adhere and invade Caco-2 cells; and whether this ability could be related to cadF, cj1349, ciaB, and/or hecA, specific genetic markers related to host cell adhesion and invasion. All adhered and invaded the cells, and harboured at least two virulence markers. The mean virulent activity shown by A. butzleri was superior to that of A. cryaerophilus (p < 0.05); but the mean adhesion and invasion values of A. lanthieri, A. skirrowii, and A. vitoriensis were even higher. Sewage isolates were significantly (p < 0.05) more adherent and invasive than the rest, and their associated gene content was higher (p < 0.05). For the first time, an association between cadF and hecA and a high adhesion capability was identified (p < 0.05). The results provide new data on the pathogenic potential of Arcobacter species present in food and water by highlighting the superiority of A. butzleri over A. cryarophilus; providing evidence on the virulence of minority species as A. lanthieri and A. vitoriensis; and confirming sewage as an important source of potentially more virulent arcobacters.

Antimicrobial Resistance and Pathogenicity of Aliarcobacter butzleri Isolated from Poultry Meat

Aliarcobacter butzleri (A. butzleri) is an emergent zoonotic food-related pathogen that can be transmitted through the consumption of poultry meat. Data regarding the pathogenicity and resistance of A. butzleri are still scarce, and the presence of virulent MDR strains of this zoonotic pathogen in poultry meat is an issue of particular concern to public health. This study aimed to characterize the pathogenicity and antimicrobial resistance profiles of A. butzleri strains isolated from poultry meat sold at retail markets in São Paulo, Brazil. The minimum inhibitory concentrations of 27 strains were determined using the broth microdilution method. The results showed that 77.7% of the isolates were resistant to clindamycin, 62.9% to florfenicol, 59.2% to nalidixic acid, 11.1% to azithromycin, 7.4% to ciprofloxacin and telithromycin, and 3.7% to erythromycin and tetracycline, although all were susceptible to gentamicin. Moreover, 55.5% of the virulent isolates were also multidrug-resistant (MDR). Three strains were selected for pathogenicity tests in vitro and in vivo. The tested strains expressed weak/moderate biofilm production and showed a diffuse adhesion pattern (3 h) in HeLa cells and toxicity in Vero cells (24 h). Experimental inoculation in 11-week-old chicks induced a transitory inflammatory enteritis. Intestinal hemorrhage and destruction of the intestinal crypts were observed in the rabbit ileal loop test. Considering the fact that Brazil is a major exporter of poultry meat, the data from this study point to the need of improvement of the diagnostic tools, as well as of the adoption of surveillance guidelines and more specific control strategies to ensure food safety, reducing the presence of pathogenic MDR strains in broilers.

Arcobacter butzleri: Up-to-date taxonomy, ecology, and pathogenicity of an emerging pathogen

Arcobacter butzleri, recently emended to the Aliarcobacter butzleri comb. nov., is an emerging pathogen causing enteritis, severe diarrhea, septicaemia, and bacteraemia in humans and enteritis, stillbirth, and abortion in animals. Since its recognition as emerging pathogen on 2002, advancements have been made in elucidating its pathogenicity and epidemiology, also thanks to advent of genomics, which, moreover, contributed in emending its taxonomy. In this review, we provide an overview of the up-to-date taxonomy, ecology, and pathogenicity of this emerging pathogen. Moreover, the implication of A. butzleri in the safety of foods is pinpointed, and culture-dependent and independent detection, identification, and typing methods as well as strategies to control and prevent the survival and growth of this pathogen are provided.