Bacteriophage influence Campylobacter jejuni types populating broiler chickens

101

121

Campylobacteriosis is the most frequent food-borne human enteritis. The major source for infection with Campylobacter spp. is broiler meat. Risk assessments consider the reduction of Campylobacter in primary production to be most beneficial for human health. The aim of this study was to test the efficacy of a bacteriophage application under commercial conditions which had proved to be effective in previous noncommercial studies under controlled experimental conditions. A phage cocktail for Campylobacter reduction was tested on three commercial broiler farms each with a control and an experimental group. Colonization of Campylobacter was confirmed prior to phage application in fecal samples. Subsequently, a phage cocktail was applied via drinking water in the experimental group (log 10 5.8 to 7.5 PFU/bird). One day after phage application, Campylobacter counts of one experimental group were reduced under the detection limit (<50 CFU/g, P ‫؍‬ 0.0140) in fecal samples. At slaughter, a significant reduction of >log 10 3.2 CFU/g cecal content compared to the control was still detected (P ‫؍‬ 0.0011). No significant reduction was observed in the experimental groups of the other trials. However, a significant drop in cecal Campylobacter counts occurred in a phage-contaminated control. These results suggest that maximum reduction of Campylobacter at the slaughterhouse might be achieved by phage application 1 to 4 days prior to slaughter.

Section: Reduction Of Campylobactersupporting

confidence: 79%

Effect of Bacteriophage Application on Campylobacter jejuni Loads in Commercial Broiler Flocks

Kittler¹,

Fischer²,

Abdulmawjood

et al. 2013

101

121

“…Very little is known regarding the ecology of this pathogen in vivo, but it is evidently highly complex. It was demonstrated recently that bacteriophage populations alter the intestinal Campylobacter contingent (37). It is known that Campylobacter spp.…”

mentioning

confidence: 99%

Campylobacter Colonization of the Turkey Intestine in the Context of Microbial Community Development

Scupham

2009

Patterns of microbial community dynamics in the turkey intestine were examined. Every week of the 18-week production cycle, cecal bacterial communities and Campylobacter loads were examined from five birds for each of two flocks. Molecular fingerprinting via the automated ribosomal intergenic spacer analysis (ARISA) and terminal restriction fragment length polymorphism (T-RFLP) of the cecal samples revealed that microbial communities changed in a time-dependent manner, and during both trials they developed via transition through three phases during the production cycle. A core component of the microbiota consisting of 11 Bacteroidetes types was present throughout both trials. In contrast, constant succession was detected in the Clostridiales populations until week 10 or 11, with few shared sequences between the flocks. Changes in Campylobacter jejuni and Campylobacter coli loads were correlated to, but not dependent on, the two acute transitions delimiting the three developmental phases.

“…The precise definition of the CI varies somewhat between studies, but the CI essentially measures the ratio of one strain to another in the model and compares it to that of the inoculum. This has been used to investigate succession of C. jejuni and Campylobacter coli (6), to examine the effect of bacteriophage on C. jejuni strains in chickens (32), and to compare the colonization ability of C. jejuni isolates (4,19,33), often with particular emphasis on the possibility of competitive exclusion as a control strategy. Comparisons of mutants versus wild type have also been used to demonstrate the importance of particular genes in colonization (25,34,38), to establish an advantage for fluoroquinoloneresistant bacteria in colonization even in the absence of antibiotic selection (22), and to validate an insertional gene expression system for C. jejuni (18).…”

mentioning

confidence: 99%

Competing Isogenic Campylobacter Strains Exhibit Variable Population Structures In Vivo

Coward

Diemen²,

Conlan

et al. 2008

Consumption of poultry contaminated with Campylobacter jejuni is a risk factor for human gastrointestinal disease. The rational development of control strategies for Campylobacter within chickens requires an understanding of the colonization process at the molecular and population levels, both within and between hosts. Experiments employing competing strains of Campylobacter have been used to investigate colonization. Implicit in these studies is the assumption that the behavior of competing strains is reproducible between experiments. Variability in the recovery of mutants from the chicken gastrointestinal tract during signature-tagged mutagenesis studies demonstrated that this is not always the case. To further investigate this phenomenon in the absence of confounding factors due to phenotypic differences between mutants, we constructed individually identifiable wild-type isogenic tagged strains (WITS) that have indistinguishable phenotypes in pure culture. By using mixtures of WITS, it is possible to monitor the relative amounts of subpopulations of essentially wild-type bacteria. Using a 2-week-old chicken model of colonization, we observed unpredictable variations in population structure both within and between experiments, even in the simplest case of two competing strains. This variation occurred both when birds were simultaneously infected with two WITS and when birds inoculated with different WITS were cohoused. We present evidence for founder effects during initial colonization with subsequent bird-to-bird transmission. We suggest that these and phenotypic variation contribute to the observed variability. These factors render simple models of colonization which do not take them into account inappropriate for Campylobacter and impact the planning and interpretation of competition experiments using this organism.