Occurrence and characteristics of fastidious Campylobacteraceae species in porcine samples.

This study investigated the prevalence and characteristics of Campylobacteraceae including a range of fastidious species in porcine samples. Over a thirteen month period caecal contents (n=402) and pork carcass swabs (n=401) were collected from three pork abattoirs and pork products (n=399) were purchased at point of sale in the Republic of Ireland. Campylobacteraceae isolates were recovered by enrichment, membrane filtration and incubation in antibiotic free media under a modified atmosphere (3% O2, 5% H2, 10% CO2 and 82% N2). Campylobacteraceae isolates were identified as either genus Campylobacter or Arcobacter and then selected species were identified by Polymerase Chain Reaction (PCR). Campylobacteraceae were isolated from 103 (26%) caecal samples, 42 (10%) carcass swabs, and 59 (15%) pork products. Campylobacter coli was the most commonly isolated species found in (37%) all sample types but many fastidious species were also isolated including Campylobacter concisus (10%), Arcobacter butzleri (8%), Campylobacter helveticus (8%), Campylobacter mucosalis (6%), Arcobacter cryaerophilus (3%), Campylobacter fetus subsp. fetus (1%), Campylobacter jejuni subsp. jejuni (1%), Campylobacter lari (0.5%), Campylobacter curvus (0.5%) and Arcobacter skirrowii (0.5%). Among all isolates, 83% contained cadF and 98% flaA. In this study 35% of porcine C. coli were resistant to ciprofloxacin but none of the fastidious species demonstrated any resistance to this drug. The level of resistance to erythromycin was very high (up to 100%) in C. concisus and C. helveticus and this is a real concern as this is the current empiric drug of choice for treatment of severe gastroenteritic Campylobacter infections. The study shows that there is a much wider range of fastidious Campylobacteraceae present in porcine samples than previously assumed with C. concisus the second most common species isolated. The majority of fastidious Campylobacteraceae isolates obtained contained virulence genes and antibiotic resistance indicating potential public health significance.

Survival characteristics of environmental and clinically derived strains of Cronobacter sakazakii in infant milk formula (IMF) and ingredients.

AIMS: The study aimed to compare survival of Cronobacter sakazakii strains in plant-derived infant milk formula (IMF) ingredients and their thermotolerance in reconstituted IMF. METHODS AND RESULTS: Inulin and lecithin were inoculated with isolates of C. sakazakii including the typed clinical strains, NCTC 11467(T) and BAA 894; a mutant strain in which the wcaD gene had been disrupted; and two environmental strains isolated from IMF processing facilities. Samples were stored and examined for C. sakazakii. All strains were still detectable in both matrices after 338 days storage, except for the mutant strain that was no longer detectable at that time. Higher numbers of the environmental strains were recoverable after 338 days than the clinical strains. The thermotolerance of the five strains was investigated in reconstituted IMF at 55, 60 and 65°C. The clinically derived type strain, NCTC 11467(T), and the mutant strain were shown to be significantly more thermotolerant than other strains tested. CONCLUSIONS: Environmental strains were more persistent than the clinical strains in inulin and lecithin, indicating that patho-adaptation may have contributed to a reduction in the desiccation tolerance phenotype. However, the thermotolerance results could indicate that the ability to produce extracellular polysaccharide decreases thermotolerance. SIGNIFICANCE AND IMPACT OF THE STUDY: These results indicate that desiccation resistance may play a role in survival of C. sakazakii in dry IMF ingredients and processing plants; however, this trait may be of less importance in clinical environs.

A method for the growth and recovery of 17 species of Campylobacter and its subsequent application to inoculated beef.

The aim of this study was to develop a universal cultural protocol, which could facilitate the growth of 17 species and 3 subspecies of Campylobacter. Enrichment media including Campylobacter Enrichment Broth (CEB) and Bolton Broth were tested against a panel of Campylobacter strains (n=53) encompassing 17 species and 3 subspecies, under a gas atmosphere containing hydrogen (2.5% O(2), 7% H(2), 10% CO(2), and 80.5% N(2)). The impact of enrichment conditions on cell motility was also investigated using fluorescent microscopy. Membrane filtration was examined as a means of selectively recovering Campylobacter from enrichment media on two different non-selective agars, Anaerobe Basal Agar (ABA) and Tryptose Blood Agar (TBA). The results showed that enrichment in CEB for 24 h at 37°C under a modified gas atmosphere followed by centrifugation and membrane filtration onto ABA allowed recovery of all species (53 strains) of Campylobacter from inoculated meat samples. After 24 h enrichment, there were higher levels of motile Campylobacter in CEB than in Bolton broth and it is proposed that this attribute aided the passage of the Campylobacter through the membrane filter. The results of this study provide a simple, but effective method for the growth and recovery of a wide range of diverse Campylobacter spp. from a meat matrix using common cultural parameters.

Tracking emerging zoonotic pathogens from farm to fork.

A combination of factors including changes in the agri-food chain, social changes, advances in detection and reporting systems coupled with bacterial adaptation and evolution have in recent years lead to the emergence of a number of zoonotic microorganisms in the food and water chain. These include multi-antibiotic resistant bacteria, verocytotoxigenic Escherichia coli, parasites such as Cyclospora on fruit, and Cyrptosporidium and Giardia in water, Enterobacter sakazakii in infant milk formula, and emergent species of Campylobacteraceae. In this paper, Enterohaemorrhagic E. coli and Campylobacteraceae are taken as examples of emergent pathogens in the meat chain. Specific factors which may have lead to their emergence are deliberated, in addition to an overview of tools for their detection and tracking, and their epidemiology and survival characteristics. Approaches to managing and controlling emergent pathogens in the agri-food chain are also discussed.