Prevalence, disease associations and risk factors for colonization with intestinal spirochaetes (Brachyspira spp.) in flocks of laying hens in north-eastern Italy

Cecal Reduction of Brachyspira and Lesion Severity in Laying Hens Supplemented with Fermented Defatted ‘Alperujo’

Antimicrobial resistance demands the development of therapeutic alternatives such as prebiotics, probiotics, and nutraceuticals. The aim of this study was to assess the antimicrobial proprieties of the nutraceutical fermented defatted “alperujo”, derived from olive oil production, in a laying hen farm (n = 122,250) endemic with avian intestinal spirochetosis (Brachyspira spp.). Part of the batch (n = 1440) was divided into six groups of 240 hens each that included 80 or 108-week-old laying hens, supplemented with 0%, 2%, or 6% fermented defatted ‘alperujo’ for a month. At the end of the experiment, eight hens from each group were autopsied and cecal content was subjected to (i) Brachyspira culture and species identification by PCRs, and (ii) direct DNA extraction and Brachyspira qPCR. Furthermore, the ceca were processed for histopathology. Microbiological isolation revealed B. pilosicoli and B. hyodysenteriae co-infection in all groups. The 80-week-old hen group 2% supplemented showed a reduction in the cecal Brachyspira content (qPCR) compared with non-supplemented hens. Cecal histopathology showed a diffuse mild infiltration of lymphocytes, plasma cells, and heterophils; and hyperplasia of the gut-associated lymphoid tissue hyperplasia which decreased in severity in 80-week-old supplemented hens. The reduction in Brachyspira colonization and the severity of the lesions observed in supplemented hens highlights a potential protective function against avian intestinal spirochetosis.

Differentiation of Brachyspira spp. isolated from laying hens using PCR-based methods and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Avian intestinal spirochetosis (AIS), an important but neglected disease in laying hens, is caused by Brachyspira pilosicoli, B. intermedia, and B. alvinipulli. Poultry are also frequently colonized by putatively nonpathogenic species such as B. murdochii and B. innocens. We evaluated the differentiation of Brachyspira species by 3 methods: sequencing of the reduced nicotinamide adenine dinucleotide (NADH) oxidase gene ( nox), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and a new multiplex (m)PCR targeting genes such as the tryptophanase A gene ( tnaA) and the p-aminobenzoyl-glutamate hydrolase subunit B gene ( abgB). Sequencing of 414 bp of the nox PCR amplification products generated from 41 pure cultures of avian Brachyspira isolates allowed presumptive species identification in 33 isolates with at least 99% identity in basic local alignment search tool analysis, including B. pilosicoli, B. intermedia, B. murdochii, B. innocens, and " B. pulli". MALDI-TOF MS analysis was found to be a reliable tool for differentiation after extension of the manufacturer's database. In the mPCR, all isolates identified as B. pilosicoli and B. intermedia were positive for abgB and tnaA, respectively. The mPCR might be very useful in detecting Brachyspira species in mixed cultures including not only nonpathogenic species, such as B. innocens, but also one of the AIS pathogens. We found that MALDI-TOF MS analysis combined with the mPCR targeting tnaA and abgB was suitable for the identification of avian isolates of B. pilosicoli and B. intermedia, 2 important agents of AIS.

Isolation and antimicrobial susceptibility of Brachy -spira species from feces of layer chickens in Germany

Objective: Anaerobic spirochetes of the genus Brachyspira are important pathogens causing swine dysentery (Brachyspira [B.] hyodysenteriae) and porcine intestinal spirochetosis (B. pilosicoli, PIS). In addition, avian intestinal spirochetosis (AIS) is caused by B. pilosicoli, B. intermedia and B. alvinipulli. Despite the economic impact of AIS, the disease has not received appropriate attention in Germany. This study was aimed at identifying Brachyspira spp. in Germany and determining their antimicrobial susceptibility. Material and methods: From 2009 to 2013, a total of 71 fecal swabs were obtained from clinically healthy layer hens from eight different commercial flocks. Brachyspira spp. culture was performed in trypticase soybean agar added with 5% sheep blood. Species determination was conducted by PCRs targeting the NADH-gen and the 16S rDNA or by nox-gene sequencing. Antimicrobial susceptibility to macrolides, lincosamides and pleuromutilins was tested by a microdilution assay. Results: Brachyspira spp. were isolated from 40 (56.3%) swabs distributed over all eight flocks. In 26 cases, the following species were determined by PCR: B. pilosicoli (n = 16), B. intermedia (2), B. innocens (3), B. murdochii (1), mixtures of B. pilosicoli/B. intermedia (2), B. innocens/B. intermedia (1), B. innocens/B. murdochii (1). Remaining isolates were characterized by noxgene sequencing as B. “pulli” (n = 9), B. alvinipulli (3), B. intermedia (1) and as not identifiable (1). Antimicrobial susceptibility testing of 37 isolates revealed minimal inhibitory concentrations 90 (MIC90) of > 128 mg/l (tylosin), 64 mg/l (lincomycin), 8 mg/l (tiamulin) and 4 mg/l (valnemulin), respectively. Comparing to breakpoints applied to pigs, these values lie within the range of resistance. Conclusion The demonstration of different Brachyspira spp., particularly B. pilosicoli, intermedia and alvinipulli in commercial layers, indicates the need of further research to assess their potential role in causing AIS in German poultry flocks. The increased antimicrobial resistance of Brachyspira spp. isolates to tylosin and pleuromutilins is likely associated with extensive use of these drugs in poultry medicine.

The Spirochete Brachyspira pilosicoli, Enteric Pathogen of Animals and Humans

Brachyspira pilosicoli is a slow-growing anaerobic spirochete that colonizes the large intestine. Colonization occurs commonly in pigs and adult chickens, causing colitis/typhlitis, diarrhea, poor growth rates, and reduced production. Colonization of humans also is common in some populations (individuals living in village and peri-urban settings in developing countries, recent immigrants from developing countries, homosexual males, and HIV-positive patients), but the spirochete rarely is investigated as a potential human enteric pathogen. In part this is due to its slow growth and specialized growth requirements, meaning that it is not detectable in human fecal samples using routine diagnostic methods. Nevertheless, it has been identified histologically attached to the colon and rectum in patients with conditions such as chronic diarrhea, rectal bleeding, and/or nonspecific abdominal discomfort, and one survey of Australian Aboriginal children showed that colonization was significantly associated with failure to thrive. B. pilosicoli has been detected in the bloodstream of elderly patients or individuals with chronic conditions such as alcoholism and malignancies. This review describes the spirochete and associated diseases. It aims to encourage clinicians and clinical microbiologists to consider B. pilosicoli in their differential diagnoses and to develop and use appropriate diagnostic protocols to identify the spirochete in clinical specimens.

Intestinal spirochaetes (Brachyspira spp.) colonizing flocks of layer and breeder chickens in Malaysia

Avian intestinal spirochaetosis causes problems including delayed onset of lay and wet litter in adult chickens, and results from colonization of the caecae/rectum with pathogenic intestinal spirochaetes (genus Brachyspira). Because avian intestinal spirochaetosis has not previously been studied in South East Asia, this investigation was undertaken in Malaysia. Faecal samples were collected from 25 farms and a questionnaire was administered. Brachyspira species were detected by polymerase chain reaction in 198 of 500 (39%) faecal samples from 20 (80%) farms, including 16 (94%) layer and four (50%) breeder farms. Pathogenic Brachyspira pilosicoli was identified in five (29%) layer and two (25%) breeder farms whilst pathogenic Brachyspira intermedia was detected in nine (53%) layer and one (12.5%) of the breeder farms. Twelve (80%) layer farms had egg production problems and 11 (92%) were positive for Brachyspira: three (25%) for B. pilosicoli and six (50%) for B. intermedia. Of three breeder farms with egg production problems, one was colonized with B. pilosicoli. Three of ten layer farms with wet litter were positive for B. pilosicoli and six for B. intermedia. Of four breeder farms with wet litter, one was colonized with B. pilosicoli and one with B. intermedia. No significant associations were found between colonization and reduced egg production or wet litter, perhaps because so many flocks were colonized. A significant association (P = 0.041) occurred between a high prevalence of colonization and faecal staining of eggs. There were significant positive associations between open-sided housing (P = 0.006), and flocks aged >40 weeks (P < 0.001) and colonization by pathogenic species.

Brachyspira and its role in avian intestinal spirochaetosis

The fastidious, anaerobic spirochaete Brachyspira is capable of causing enteric disease in avian, porcine and human hosts, amongst others, with a potential for zoonotic transmission. Avian intestinal spirochaetosis (AIS), the resulting disease from colonisation of the caeca and colon of poultry by Brachyspira leads to production losses, with an estimated annual cost of circa £ 18 million to the commercial layer industry in the United Kingdom. Of seven known and several proposed species of Brachyspira, three are currently considered pathogenic to poultry; B. alvinipulli, B. intermedia and B. pilosicoli. Currently, AIS is primarily prevented by strict biosecurity controls and is treated using antimicrobials, including tiamulin. Other treatment strategies have been explored, including vaccination and probiotics, but such developments have been hindered by a limited understanding of the pathobiology of Brachyspira. A lack of knowledge of the metabolic capabilities and little genomic information for Brachyspira has resulted in a limited understanding of the pathobiology. In addition to an emergence of antibiotic resistance amongst Brachyspira, bans on the prophylactic use of antimicrobials in livestock are driving an urgent requirement for alternative treatment strategies for Brachyspira-related diseases, such as AIS. Advances in the molecular biology and genomics of Brachyspira heralds the potential for the development of tools for genetic manipulation to gain an improved understanding of the pathogenesis of Brachyspira.

Swine dysentery: aetiology, pathogenicity, determinants of transmission and the fight against the disease

Swine Dysentery (SD) is a severe mucohaemorhagic enteric disease of pigs caused by Brachyspira hyodysenteriae, which has a large impact on pig production and causes important losses due to mortality and sub-optimal performance. Although B. hyodysenteriae has been traditionally considered a pathogen mainly transmitted by direct contact, through the introduction of subclinically infected animals into a previously uninfected herd, recent findings position B. hyodysenteriae as a potential threat for indirect transmission between farms. This article summarizes the knowledge available on the etiological agent of SD and its virulence traits, and reviews the determinants of SD transmission. The between-herds and within-herd transmission routes are addressed. The factors affecting disease transmission are thoroughly discussed, i.e., environmental survival of the pathogen, husbandry factors (production system, production stage, farm management), role of vectors, diet influence and interaction of the microorganism with gut microbiota. Finally, prophylactic and therapeutic approaches to fight against the disease are briefly described.

Complete Genome Sequence of the Porcine Strain Brachyspira pilosicoli P43/6/78(T.)

Reported herein is the complete genome sequence of Brachyspira pilosicoli strain P43/6/78^T, isolated from a pig with clinical disease. This sequence will aid in the study of genome-wide comparison among Brachyspira species.

Occurrence of viable Brachyspira spp. on carcasses of spent laying hens from supermarkets

Brachyspira spp. are frequent inhabitants of the chicken's intestine and some have been associated with enteric disease in humans. We studied contamination with Brachyspira spp. of carcasses of spent laying hens as a possible source of infections for humans and animals that may eat this meat. Eleven batches of hen carcasses, for a total of 110 carcasses, were bought in Belgian supermarkets during 2009-2010. Carcass rinse samples were examined for the presence of Brachyspira. Brachyspira spp. were cultured from some carcass in all batches. Besides presumably non-pathogenic species such as Brachyspira murdochii and Brachyspira innocens, the poultry pathogen Brachyspira intermedia and the poultry and suspected human pathogen Brachyspira pilosicoli were identified in 7/11 and 1/11 carcass batches, respectively, at high numbers, as shown using quantitative polymerase chain reactions. Multilocus sequence typing (MLST) demonstrated the presence of 2 and 13 MLST types of B. pilosicoli and B. intermedia, respectively, with all strains belonging to novel MLST types. The findings show that carcasses of spent laying hens are commonly contaminated with high numbers of Brachyspira spp., including the suspected zoonotic agent B. pilosicoli.

Vaccination with an autogenous bacterin fails to prevent colonization by Brachyspira intermedia in experimentally infected laying chickens

Avian intestinal spirochaetosis (AIS) is a disease complex affecting adult laying and breeding chickens associated with infection by anaerobic intestinal spirochaetes of the genus Brachyspira. Options for control of AIS are limited, as few effective antimicrobial agents are registered for use in laying chickens. One of the two most commonly encountered pathogenic species in AIS is B. intermedia, and the aim of the current study was to determine whether a B. intermedia bacterin vaccine would help control AIS caused by this species. An autogenous bacterin was prepared from B. intermedia strain HB60 and given twice intramuscularly at a 3-week interval to 12 laying chickens housed in individual cages. Twelve non-vaccinated control chickens were placed in adjacent cages in the same room. Two weeks after the second vaccination all the chickens were experimentally challenged with B. intermedia HB60 by crop tube. Subsequently faeces were cultured for spirochaetes every 2-3 days, faecal water content and chicken weight were measured weekly, and egg numbers and weights were recorded daily. Serum was taken prior to both vaccinations, at the time of challenge and at euthanasia. The chickens were killed 6 weeks post-challenge. The vaccinated chickens showed seroconversion to the vaccine, but antibody levels declined significantly post-infection. In comparison, the non-vaccinated chickens showed seroconversion post-infection. The reason for the reduction in the antibody levels in the vaccinated chickens after infection was not explained. At some point all the chickens excreted spirochaetes in their faeces, and the duration of excretion was not different between vaccinated and non-vaccinated chickens. There were no differences in faecal water content, chicken weights, egg production, or gross and microscopic caecal lesions between vaccinated and non-vaccinated chickens. In conclusion, an autogenous bacterin vaccine did not prevent infection with B. intermedia in laying chickens.