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Like Campylobacter and Helicobacter spp., Arcobacter spp. possess two flagellin genes ( flaA and flaB) located adjacent to each other. The aim of this study was to characterize the flagellin proteins of Arcobacter spp., because these proteins are known virulence factors in the Epsilonproteobacteria, to which these three species belong. With the exception of Arcobacter nitrofigilis, Arcobacter flagellins are almost half the size of those in other Epsilonproteobacteria. Arcobacter flagellin proteins lack a large part of the variable central region. The low homology observed among flagellins of different Arcobacter species indicates genetic heterology between the members of this genus. Unlike in other Epsilonproteobacteria, the transcription of flagellin genes is not regulated by σ28- or σ54-dependent promoters, which suggests that transcription must be regulated in a different way in Arcobacter spp. Mutational studies revealed that only FlaA is needed for the motility of Arcobacter spp. Quantitative PCR analysis showed that transcription of flaB is higher at 30 °C than at 37 °C. Mutation of flaB had no effect on motility or on flaA transcription while mutation of flaA abolished motility and increased the transcription of flaB. These results underline that the genus Arcobacter is an unusual taxon in the epsilon subdivision of the Proteobacteria. [ABSTRACT FROM AUTHOR]

Clostridium perfringens is a common cause of intestinal disease in animals and humans. Its pathogenicity is attributed to the toxins it can produce, including the beta2 toxin. The presence of cpb2, the gene encoding the beta2 toxin, has been associated with diarrhoea in neonatal piglets and humans. However, the exact role of the beta2 toxin in the development of diarrhoea is still unknown. In this study we investigated the level of cytotoxicity to porcine IPI-21 and human Caco-2 cell-lines caused by porcine and human cpb2-harbouring C. perfringens and the significance of the beta2 toxin for the induction of cell cytotoxicity. Supernatants of porcine cpb2-harbouring C. perfringens strains were cytotoxic to both cell lines. Cell cytotoxicity caused by supernatant of human cpb2-harbouring C. perfringens strains was variable among strains. However, removal of the beta2 toxin by anti-beta2 toxin antibodies or degradation of the beta2 toxin by trypsin did not reduce the cytotoxic effect of any of the supernatants. These data suggest that beta2 toxin does not play a role in the development of cell cytotoxicity in in vitro experiments. In vivo studies are necessary to definitely define the role of beta2 toxin in the development of cell cytotoxicity and subsequent diarrhoea., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Clostridium perfringens is one of the major causes of intestinal disease in humans and animals. Its pathogenicity is contributed to by the production of a variety of toxins. In addition, predisposing environmental factors are important for the induction of C. perfringens-associated enteritis as shown by infection models. Environmental contamination, gastric and intestinal pH, intestinal microflora, nutrition, concurrent infections, and medical interventions may influence the intestinal colonization, growth, and toxin production by C. perfringens. Prevention of C. perfringens-associated enteritis may be mediated by the use of feed additives like probiotics, prebiotics, organic acids, essential oils, bacteriophages, lysozymes, bacteriocins, and antimicrobial peptides. Here we summarize and discuss published data on the influence of different environmental predisposing factors and preventive measures. Further research should focus on feed composition and feed additives in order to prevent C. perfringens-associated enteritis., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Since 2006 increasing numbers of laying hen flocks with decreased production have been reported in the Netherlands. At necropsy, birds from affected flocks showed multifocal areas of necrosis in the duodenum. Histologically the duodenum had moderate to marked villus atrophy and fusion with crypt hyperplasia and a mixed inflammatory infiltrate within the lamina propria underlying focal areas of degenerative epithelium. Multifocally, free within the intestinal lumen and associated with epithelial necrosis, were marked numbers of large rod-shaped bacteria. Anaerobic culturing and subsequent toxin typing revealed, in 19 out of 73 affected birds, the presence of Clostridium perfringens strains, either type A or type C harbouring the atypical allele of cpb2 and netB. Eighteen out of these 19 birds carried C. perfringens strains capable of producing beta2 toxin in vitro and all of these birds harboured C. perfringens strains capable of producing NetB toxin in vitro. In contrast, specific pathogen free (SPF) birds lacked gross or histological lesions in their duodenum, and C. perfringens type C was isolated from four out of 15 SPF birds tested. One of these isolates harboured the consensus three allele of cpb2 that produced beta2 toxin in vitro. None of the C. perfringens isolates originating from SPF birds harboured netB. These findings might indicate that the NetB toxin produced by C. perfringens is associated with subclinical necrotic enteritis in layers, whereas the involvement of beta2 toxin in subclinical necrotic enteritis, if any, might be variant dependent.

Cryptosporidium infection was associated with colitis and cystitis in 2 green iguanas (Iguana iguana). The disease was characterized by a chronic clinical course of cloacal prolapses and cystitis. Histological examination of the gut and urinary bladder showed numerous Cryptosporidium developmental stages on the surface of the epithelium with mixed inflammatory response in the lamina propria. Cryptosporidium oocysts were visualised in a cytological preparation of the faeces. Based on the small subunit ribosomal RNA gene the cryptosporidia were characterized as belonging to the intestinal cryptosporidial lineage, but not to Cryptosporidium saurophilum or Cryptosporidium serpentis species., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The virulence of Clostridium perfringens, a bacterium causing enteritis and enterotoxaemia in domestic and wild animals and humans, results largely from its ability to produce toxins. In 1997, an unknown toxin of C. perfringens, the beta2-toxin, and its encoding gene cpb2 were described. Since that time numerous studies have been published dealing with a possible association of cpb2-harbouring strains of C. perfringens and the occurrence of enteric disease in domestic and wild animals and humans. This article offers an overview of the current literature on the spread and pathological significance of cpb2-harbouring C. perfringens. Unambiguous conclusions on the prevalence of cpb2 and the contribution of beta2-toxin to the disease cannot be drawn from existing studies but in some animal species a strong correlation between the presence of cpb2-harbouring C. perfringens, the beta2-toxin and enteric disease has been reported., (Copyright (c) 2008 Elsevier Ltd. All rights reserved.)

An 11-yr-old female hamadryas baboon (Papio hamadryas) that died with a history of diarrhea and anorexia was submitted for necropsy. Major pathologic changes were restricted to the gastrointestinal tract. The small intestinal contents were watery and sanguinous, with a deepening of the red color in the large intestines. The intestinal mucosa was hyperemic. Microscopically, lesions consisted of surface epithelial cell necrosis in association with numerous rod-shaped bacteria and high numbers of Trichuris cynocephalus nematodes. Culturing of the small intestine yielded Clostridium perfringens. No other pathogenic bacteria were cultured using routine bacteriologic techniques. Polymerase chain reaction (PCR) analysis classified the Clostridium perfringens as type A cpb2-positive. Immunohistochemical examination with anti-beta2-toxin antibodies revealed beta2-toxin in close approximation with the intestinal lesions.

Clostridium perfringens which is a causative agent of several diseases in animals and humans is capable of producing a variety of toxins. Isolates are typed into five types on the basis of the presence of one or more of the four major toxins genes, i.e. cpa, cpb, etx, and iap. A decade ago another toxin termed beta2 (beta2) and its gene (cpb2) were identified. Two alleles of cpb2 are known and a possible link between differences in gene expression and allelic variation has been reported. A correlation between the level of expression and the origin of the isolates has also been suggested. The demonstration and typing of the cpb2 gene in the genome of isolates can be seen as a vital part of research on the role of the beta2 toxin in the pathogenesis of disease. This study describes a PCR with a single primer set which in contrast to published primer sets recognizes both alleles. Subsequent restriction enzyme analysis of the PCR product enables typing of the alleles. Applying this protocol on a total of 102 isolates, a sub-variant was found which occurred only in C. perfringens isolates from pigs and appeared to be the predominant variant found in C. perfringens isolates from this species.

Surfactant proteins A and D are pattern recognition molecules that play a role in pulmonary host defence. In this paper, we describe for the first time the expression and localisation of both collectins in various porcine tissues using a combination of in situ hybridisation (ISH), RT-PCR and immunohistochemistry (IHC). SP-D was expressed in several tissues including lung, tongue, intestinal tract, thymus, skin, gall bladder and lacrimal gland. Focal SP-D expression was detected in oesophagus, stomach, kidney, liver, prostate and spleen with both histological techniques. These tissues tested negative with RT-PCR. In contrast, SP-A expression was limited to the lung as measured by ISH and IHC. Interestingly, analysis by RT-PCR showed that thymus, trachea, jejunum and duodenum are positive for the presence of SP-A mRNA. We conclude that the combination of different methods can be advantageous if tissue-specific expression is studied. The importance of SP-D in innate immune defence of the pig is underlined by its expression at the potential ports of entry of pathogens.

Collectins are members of the family of vertebrate C-type lectins. They have been found almost exclusively in mammals, with the exception of chicken MBL. Because of their important role in innate immunity, we sought to identify other collectins in chicken. Using the amino acid sequences of known collectins, the EST database was searched and related to the chicken genome. Three chicken collectins were found and designated chicken Collectin 1 (cCL-1), chicken Collectin 2 (cCL-2), and chicken Collectin 3 (cCL-3), which resemble the mammalian proteins Collectin Liver 1, Collectin 11 and Collectin Placenta 1, respectively. Additionally, a lectin was found which resembled Surfactant Protein A, but lacked the collagen domain. Therefore, it was named chicken Lung Lectin (cLL). Tissue distribution analysis showed cCL-1, cCL-2 and cCL-3 are expressed in a wide range of tissues throughout the digestive, the reproductive and the lymphatic system. Similar to SP-A, cLL is mainly localized in lung tissue. Phylogenetic analysis indicates that cCL-1, cCL-2 and cCL-3 represent new subgroups within the collectin family. The newly found collectins may have an important function in avian host defence. Elucidation of the role of these pattern-recognition molecules could lead to strategies that thwart infectious diseases in poultry, which could also be beneficial for public health.

Cathelicidins, antimicrobial peptides with broad spectrum activity, have been almost exclusively found in mammals. Here, we report the cloning of a novel avian cathelicidin, chicken myeloid antimicrobial peptide 27 (CMAP27) from chicken bone marrow cells. A combined expressed sequence tag (EST) and genomic based search revealed a cathelicidin-like gene located at the terminus of chromosome 2. Reverse transcriptase-polymerase chain reaction (RT-PCR) and 5'RACE techniques resulted in a 154 amino acid prepropeptide, homologous to chicken cathelicidin 1 (51%) and most similar to alpha-helical myeloid antibacterial peptides (MAPs; 29-33%). A putative elastase cleavage site (LVQRG/RF) suggests the production of a 27 amino acid antimicrobial peptide, predicted to adopt an alpha-helical configuration followed by a hydrophobic tail. Comparative analyses between antimicrobial peptide domains showed marked similarity between CMAP27 and MAP members of the bovidae family, but not with the alpha-helical chicken cathelicidin 1. Strongest expression of CMAP27 mRNA was found in myeloid/lymphoid tissues, testis and uropygial gland. In accordance with the phylogenetic tree analysis, these findings support the theory of a common ancestral cathelicidin gene and suggest an important role for cathelicidins in chicken innate host defense.

Whether an infection with Salmonella spp. leads to a disease largely depends on the virulence of the strain and the constitution of the host. The virulence of the strain is determined by so-called virulence factors. Whereas a number of virulence factors of Salmonella have been identified only recently, others have been studied for decades. These latter virulence factors i.e., virulence-plasmids, toxins, fimbriae and flagella are therefore referred to as "classic" virulence factors. Here we present an overview on the distribution of (genes coding for) these virulence factors among Salmonella spp. The pathogenicity islands of Salmonella are also reviewed, all be it briefly, since they contain a major part of the virulence genes.