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A major cause of bacterial food-borne infection, 'Campylobacter jejuni' (C. jejuni) is present in eggs and hatchery fluff and it is possible that the bacteria could vertically transmit from hens to progeny. A study to verify this was conducted in Iceland where only eggs imported from grandparent flocks in Sweden are used to establish breeding stocks minimizing the chances of horizontal transmission of isolates and the results supported the possibility of vertical transmission.

The flaA and flaB flagellin genes of Campylobacter are not entirely identical. One segment of the flagellin sequence evolves while the other segment is maintained by conversion or recombination.

Abstract Background Because biotechnological uses of bacteriophage gene products as alternatives to conventional antibiotics will require a thorough understanding of their genomic context, we sequenced and analyzed the genomes of four closely related phages isolated from Clostridium perfringens, an important agricultural and human pathogen. Results Phage whole-genome tetra-nucleotide signatures and proteomic tree topologies correlated closely with host phylogeny. Comparisons of our phage genomes to 26 others revealed three shared COGs; of particular interest within this core genome was an endolysin (PF01520, an N-acetylmuramoyl-L-alanine amidase) and a holin (PF04531). Comparative analyses of the evolutionary history and genomic context of these common phage proteins revealed two important results: 1) strongly significant host-specific sequence variation within the endolysin, and 2) a protein domain architecture apparently unique to our phage genomes in which the endolysin is located upstream of its associated holin. Endolysin sequences from our phages were one of two very distinct genotypes distinguished by variability within the putative enzymatically-active domain. The shared or core genome was comprised of genes with multiple sequence types belonging to five pfam families, and genes belonging to 12 pfam families, including the holin genes, which were nearly identical. Conclusions Significant genomic diversity exists even among closely-related bacteriophages. Holins and endolysins represent conserved functions across divergent phage genomes and, as we demonstrate here, endolysins can have significant variability and host-specificity even among closely-related genomes. Endolysins in our phage genomes may be subject to different selective pressures than the rest of the genome. These findings may have important implications for potential biotechnological applications of phage gene products.

The mean contamination and maximum contamination data from comparison between product lots of retail Icelandic broiler chicken carcasses and isolates from cases of human campylobacteriosis are used to score each lot for the Campylobacter contamination observed for sampled carcasses. The results have indicated that cases of broiler-borne campylobacteriosis might occur in clusters and that the differences in mean contamination levels have provided a basis for regulatory action that is more specific than a presence-absence standard.

The DNA sequence of a flaA short variable region (SVR) was used to analyze random population of Campylobacter isolates to investigate the weakly clonal population structure of members of the genus. The rate of migration between populations appears to limit the distribution of sequences and results in a weakly clonal population structure.

C ampylobacter is an important foodborne human pathogen, which has traditionally been studied using a variety of selective cultivation methods. Here we use next-generation sequencing to ask the following: (i) how selective are commonly used C ampylobacter cultivation methods relative to the initial sample and (ii) how do the specificity and sensitivity of these methods compare with one another? To answer these questions, we used 16 S rRNA tagged-pyrosequencing to sequence directly from a pooled fecal sample representing a c. 16 000 bird poultry flock and compared these data to exhaustive sequencing of colonies formed after plating. We compared five commonly used media [ Cefex, Cape Town, modified cefoperazone charcoal deoxycholate agar ( mCCDA), Campy-Line agar ( CLA), and Campy-CVA agar ( CVA)], two incubation atmospheres (10% CO2, 5% O2, 85% N2 and 10% CO2, 10% H2, 80% N2), and two incubation temperatures (37 and 42 ° C). Analysis of 404 104 total sequence reads, including 19 472 total fecal reads, revealed C ampylobacter represented only a small proportion (< 0.04%) of sequences present in the feces, but 88-97% of sequences from each media type. Incubation atmosphere had little effect on recovery, but a significant difference in media specificity (more non- C ampylobacter OTUs; P = 0.028) was found at 42 vs. 37 ° C. The most common non- C ampylobacter sequence type was P roteus, which ranged from 0.04% of sequences ( mCCDA) to 10.8% ( Cape Town). High-throughput sequencing provides a novel and powerful approach to measure the performance of selective media, which remain widely used for research and regulatory purposes. [ABSTRACT FROM AUTHOR]

Capacitance monitoring is commonly used as an efficient means to generate growth curves of bacterial pathogens. However, the use of capacitance monitoring with Campylobacter spp. was previously determined to be difficult due to the complexity of the required media. We investigated capacitance monitoring using a simplified medium for the efficient and reproducible construction of growth curves for Campylobacter spp. It was determined that Campylobacter spp. should initially be propagated on Mueller Hinton plates in a microaerobic atmosphere (5% O2, 10% CO2, 85% N2) at 37C for 24 h, followed by transfer to Mueller Hinton biphasic cultures for 6 h at 37C in a microaerobic atmosphere. Serial dilutions of the Campylobacter spp. cultures should be used for inoculation of Bactometer wells that contain 1 mL Mueller Hinton broth supplemented with 0.1 M sodium pyruvate for the completion of Campylobacter spp. growth curves with the Bactometer. PRACTICAL APPLICATIONS Growth rates can vary greatly among Campylobacter isolates; therefore, the rapid and reproducible methods described will prove useful in studies where the generation of growth curves is critical for subsequent experimental analyses. [ABSTRACT FROM AUTHOR]