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1.
The survival of Brachyspira hyodysenteriae and Brachyspira pilosicoli was investigated at 10 degrees C in laboratory microcosms consisting of soil, porcine faeces, and in soil mixed with 10% porcine faeces, respectively. By plate spreading, survival of B. hyodysenteriae was found to be 10, 78 and 112 days in soil, soil mixed with 10% faeces, and in porcine faeces, respectively. The identities of the colonies on the plates were confirmed using PCR targeting 23S rDNA for specific detection of B. hyodysenteriae. A positive PCR signal could be obtained up to 112 days in all microcosms by direct extraction of DNA from microcosms followed by PCR.The survival time for B. pilosicoli was 119 days in pure soil and 210 days in soil mixed with 10% porcine faeces and in pure faeces, respectively, as determined by plate spreading followed by PCR. On the other hand, by direct extraction of DNA followed by specific detection by PCR. B. pilosicoli could be detected up to 330 days in all microcosms.Dot blot hybridisation with digoxigenin-labelled specific oligonucleotide probe targeting rDNA could not be used for direct detection of Brachyspira spp. from microcosms due to low sensitivity. However, it was used for confirmation of the identity of colonies and proved to be a useful technique.These results show that the two Brachyspira species may survive in outdoor environment for the times shown in these investigations using laboratory microcosms.  相似文献   

2.
Feral pigs are recognized as being a potential reservoir of pathogenic microorganisms that can infect domestic pigs and other species. The aim of this study was to investigate whether feral pigs in Western Australia were colonized by the pathogenic enteric bacteria Lawsonia intracellularis, Brachyspira hyodysenteriae and/or Brachyspira pilosicoli. A total of 222 feral pigs from three study-populations were sampled. DNA was extracted from faeces or colonic contents and subjected to a previously described multiplex PCR for the three pathogenic bacterial species. A subset of 61 samples was cultured for Brachyspira species. A total of 42 (18.9%) of the 222 samples were PCR positive for L. intracellularis, 18 (8.1%) for B. hyodysenteriae and 1 (0.45%) for B. pilosicoli. Four samples were positive for both L. intracellularis and B. hyodysenteriae. Samples positive for the latter two pathogens were found in pigs from all three study-sites. A strongly haemolytic B. hyodysenteriae isolate was recovered from one of the 61 cultured samples. Comparison of a 1250-base pair region of the 16S rRNA gene amplified from DNA extracted from the isolate and five of the B. hyodysenteriae PCR positive faecal samples helped confirm these as being from B. hyodysenteriae. This is the first time that B. hyodysenteriae has been detected in feral pigs. As these animals range over considerable distances, they present a potential source of B. hyodysenteriae for any domesticated pigs with which they may come into contact.  相似文献   

3.
Diarrhoea in growing and finishing pigs is usually caused by infectious agents and laboratory diagnosis is a prerequisite for efficient therapy. Cultivation of Brachyspira hyodysenteriae or Brachyspira pilosicoli and detection of Lawsonia intracellularis by means of immunofluorescence tests (IFT) are time-consuming and in some cases lack sensitivity. A multiplex-PCR was designed to detect simultaneously these three pathogens in faeces and tissue samples, allowing the differential diagnosis of dysentery, intestinal spirochaetosis and proliferative enteropathy. Detection limits for B. hyodysenteriae, B. pilosicoli and L. intracellularis were 10(4), 10(2) and 10(3) copies respectively. Agreement between multiplex-PCR and nested-PCR or cultivation was considered substantial to almost perfect. Agreement between multiplex-PCR and IFT in detecting L. intracellularis was only moderate, which was probably related to false-positive results given by IFT. The multiplex-PCR described herein is a valuable tool for the rapid and simultaneous detection of three different pathogens in porcine samples causing enteric diseases.  相似文献   

4.
Principal aim of this study was to examine fecal samples from pigs suffering from diarrhea for the presence of Lawsonia intracellularis, Brachyspira hyodysenteriae and Brachyspira pilosicoli. The molecular techniques such as PCR and nested PCR were employed to detect the presence of p78 fragment of genomic DNA specific for Lawsonia intracellularis as well as fragment of tlyA gene specific for Brachyspira hyodysenteriae and 16S rDNA gene of Brachyspira pilosicoli. We assumed that about 25% of pigs were infected with Lawsonia intracellularis, about 10% with Brachyspira hyodysenteriae and only 0,8% with Brachyspira pilosicoli. In about 3% mixed infection with L. intracellularis and B. hyodysenteriae was observed. Results were comparable in herds that differed in quantity, breeding technology, hygienic standards and preventive treatment with different chemotherapeutics.  相似文献   

5.
The Brachyspira (formerly Serpulina) species rrl gene encoding 23S ribosomal RNA (rRNA) was used as a target for amplification of a 517bp DNA fragment by polymerase chain reaction (PCR). The primers for PCR amplification had sequences that were conserved among Brachyspira 23S rRNA gene and were designed from nucleotide sequences of Brachyspira hyodysenteriae, Serpulina intermedia, Brachyspira innocens and Brachyspira pilosicoli available from the GenBank database. Digestion of PCR-generated products from reference and field isolates of swine intestinal spirochetes with restriction enzymes Taq I and Alu I revealed five restriction fragment length polymorphism (RFLP) patterns. Each RFLP pattern corresponded to previously established genetic groups including B. hyodysenteriae (I), S. intermedia/B. innocens (II), Brachyspira murdochii (III), B. pilosicoli (IV) and B. alvinipulli (V). The 23S rRNA PCR/RFLP provided a relatively simple genotypic method for identification of porcine pathogenic B. hyodysenteriae and B. pilosicoli.  相似文献   

6.
The aim of the present study was to survey the prevalences of the enteric pathogens Brachyspira hyodysenteriae, Brachyspira pilosicoli and Lawsonia intracellularis in Swedish growing pigs and in the Swedish wild boar population and to relate these findings to clinical signs. The study included 105 randomly selected herds, constituting approximately one third of Swedish herds with a herd size of >100 sows. The herds were located all over the country. In these herds, growth promoters were not used and pigs sampled were not subjected to any medication. From each herd, samples were taken from 10 growing pigs aged 8-12 weeks, corresponding to approximately 2.5% of all growing pigs present in the herd at the sampling occasion. If possible, the samples were taken from pigs with diarrhoea. Forty-eight faecal samples and 71 rectal swabs were also taken from free-living wild boars (31 piglets, 19 growers and 21 adult animals) at shooting. The samples were analysed by culture and biochemical tests for the presence of Brachyspira spp. and by nested PCR for the presence of L. intracellularis. Brachyspira hyodysenteriae was not demonstrated in any sample. Brachyspira intermedia was detected in 22 samples originating from 15 herds, Brachyspira innocens/Brachyspira murdochii was detected in 370 samples from 82 herds and B. pilosicoli was detected in 134 samples originating from 34 herds. In 21 herds and in 534 samples, no Brachyspira spp. were detected. Lawsonia intracellularis was demonstrated in 285 samples from 50 herds. Further, 418 samples from conventional herds were negative with respect to L. intracellularis and in 345 samples the PCR had been inhibited. All samples from the wild boars were negative for Brachyspira spp., 12 of 48 samples were negative for L. intracellularis, and in 36 wild boar samples, the PCR was inhibited.  相似文献   

7.
This study aimed to obtain information about the types of spirochaetes colonising urban dogs in Thailand, and to investigate their pathogenic potential in a day-old chick model of intestinal spirochaetosis. Spirochaetes were isolated from the faeces of six of 47 (12.8%) healthy dogs and 11 of 104 (10.6%) dogs with diarrhoea. Their biochemical properties and 16S ribosomal DNA sequences were analysed. Four isolates were identified as Brachyspira pilosicoli, three resembled "Brachyspira pulli", nine clustered with "Brachyspira canis" and one was similar to Brachyspira intermedia. Canine isolates of B. pilosicoli, "B. canis" and "B. pulli", and control strains of Brachyspira hyodysenteriae, B. pilosicoli and Brachyspira innocens colonised experimentally infected day-old chicks. The chicks did not develop diarrhoea, but were significantly lighter than the non-infected group and those infected with B. innocens after 21 days (P<0.05). Using immunohistochemistry, spirochaetes were observed covering the surface epithelium and in the crypts of chicks in all three groups challenged with the canine isolates. Variable histopathological changes were seen, with the greatest inflammatory cell infiltration into the lamina propria occurring in the group infected with "B. pulli". Canine "B. canis", "B. pulli" and B. pilosicoli isolates may have pathogenic potential.  相似文献   

8.
Lawsonia (L.) intracellularis, Brachyspira (B.) hyodysenteriae and B. pilosicoli are important pathogens in domestic pig production world-wide, responsible for porcine intestinal adenomatosis, swine dysentery, and porcine intestinal spirochetosis, respectively. Conventional PCR is the major diagnostic tool in the detection of the three pathogens, but the sole detection of bacterial DNA might lead to misinterpretations of results with respect to their clinical relevance, especially with mixed infections. Thus, the present study targeted the detection and quantification of the three pathogens in samples from herds with a case history of diarrhoea. Herds and samples were selected by the practitioners on a voluntary basis. Results were based on 1176 individual samples from 95 herds from Southern Germany. The pathogens were detected simultaneously by multiplex real-time PCR. The overall prevalence for L. intracellularis, B. hyodysenteriae and B. pilosicoli was 12.6%, 8.4% and 3.2% in faecal samples and 48.4%, 24.2% and 31.6% in herds, respectively. Sixty one percent, 82.6%, and 73.4% of herds positive for L. intracellularis, B. hyodysenteriae, and B. pilosicoli, respectively, had mixed infections. Median log values of DNA equivalents/g of faeces for L. intracellularis, B. hyodysenteriae and B. pilosicoli were 3.3, 5.9 and 3.2, with maxima of 8.3, 8.0 and 6.3, respectively. Within herd prevalence of B. hyodysenteriae and B. pilosicoli as well as the load of B. hyodysenteriae were significantly associated with the severity of diarrhoea.  相似文献   

9.
A hippurate-negative biovariant of Brachyspira pilosicoli (B. pilosicolihipp-) is occasionally isolated in diarrhoeic pigs in Finland, often concomitantly with hippurate-positive B. pilosicoli or Lawsonia intracellularis. We studied pathogenicity of B. pilosicolihipp- with special attention paid to avoiding co-infection with other enteric pathogens. Pigs were weaned and moved to barrier facilities at the age of 11 days. At 46 days, 8 pigs were inoculated with B. pilosicolihipp- strain Br1622, 8 pigs were inoculated with B. pilosicoli type strain P43/6/78 and 7 pigs were sham-inoculated. No signs of spirochaetal diarrhoea were detected; only one pig, inoculated with P43/6/78, had soft faeces from day 9 to 10 post inoculation. The pigs were necropsied between days 7 and 23 after inoculation. Live pigs were culture-negative for Brachyspira spp., but B. pilosicolihipp- was reisolated from necropsy samples of two pigs. The lesions on large colons were minor and did not significantly differ between the three trial groups. In silver-stained sections, invasive spirochaetes were detected in colonic mucosae of several pigs in all groups. Fluorescent in situ hybridisation for genus Brachyspira, B. pilosicoli and strain Br1622 was negative. However, in situ detection for members of the genus Leptospira was positive for spirochaete-like bacteria in the colonic epithelium of several pigs in both infected groups as well as in the control group. L. intracellularis, Salmonella spp., Yersinia spp. and intestinal parasites were not detected. The failure of B. pilosicoli strains to cause diarrhoea is discussed with respect to infectivity of the challenge strains, absence of certain intestinal pathogens and feed and management factors.  相似文献   

10.
Swine dysentery (SD) is a common disease among pigs worldwide, which contributes to major production losses. Antimicrobial susceptibility testing of B. hyodysenteriae, the etiological agent of SD, is mainly performed by the agar dilution method. This method has certain limitations due to difficulties in interpretation of results. The aim of this study was the analysis of antimicrobial susceptibility of Brachyspira hyodysenteriae (B. hyodysenteriae) Polish field isolates by broth microdilution procedure. The study was performed on 21 isolates of B. hyodysenteriae, collected between January 2006 to December 2010 from cases of swine dysentery. VetMIC Brachyspira panels with antimicrobial agents (tiamulin, valnemulin, doxycycline, lincomycin, tylosin and ampicillin) were used for susceptibility testing of B. hyodysenteriae. The minimal inhibitory concentration (MIC) was determined by the broth dilution procedure. The lowest antimicrobial activity was demonstrated for tylosin and lincomycin, with inhibition of bacterial growth using concentrations > 128 microg/ml and 32 microg/ml, respectively. In the case of doxycycline, the MIC values were < or = 2.0 microg/ml. No decreased susceptibility to tiamulin was found among the Polish isolates and MIC values for this antibiotic did not exceed 1.0 microg/ml. The results of the present study confirmed that Polish B. hyodysenteriae isolates were susceptible to the main antibiotics (tiamulin and valnemulin) used in treatment of swine dysentery. Further studies are necessary to evaluate a possible slow decrease in susceptibility to tiamulin and valnemulin of B. hyodysenteriae strains in Poland.  相似文献   

11.
A survey is given on the occurrence and distribution of different Brachyspira species in pigs, in the northwest of Germany. In total 2975 specimen (feces, fecal swabs, colon) were taken and sent for laboratory analysis during the years 1997 to 1999. 1218 Brachyspira (B.) strains were found by cultural analysis. 1757 samples (59%) were negative. The cultural and biochemical differentiation revealed 720 (59.1%) strains B. hyodysenteriae (77.5% were indole negative), 22 (1.8%) B. pilosicoli, 29 (2.4%) B. intermedia, 167 (3.7%) B. innocens and 114 (9.4%) B. murdochii. 166 (13.6%) strains could not be identified. These strains could either not be compared with any of the described species by the methods used or it was impossible to achieve a pure culture from these isolates. The results demonstrate the wide spread of B. hyodysenteriae in pig herds in the northwest of Germany with a very high prevalence of indole negative strains. The most frequent strain was B. hyodysenteriae. B. pilosicoli which causes spirochaetal diarrhoea was rarely isolated and seems not to play an important role in Germany. Experience from routine cultures for Brachyspira give evidence that it is more useful to examine faeces from single pigs instead of pooled samples from a herd. It is recommended to use special transport media for the transport of the specimen.  相似文献   

12.
Faeces samples were taken three times at two-week intervals, from the farrowing units of four herds of known Brachyspira (formerly Serpulina) status and one of unknown Brachyspira status. Brachyspira hyodysenteriae, Brachyspira pilosicoli, Brachyspira intermedia and Brachyspira group III were isolated from the faecal samples from the weaners in the herds using either a maximum of 50 ppm of olaquindox or no feed additives. The detection rates were relatively consistent. However, B hyodysenteriae was not detected at one sampling in a known positive herd. The prevalence of Brachyspira species was also studied in feeder pigs originating from LSO 2000 health class farrowing units, comparable with specific pathogen-free herds. These farms were free from swine dysentery, sarcoptic mange, swine enzootic pneumonia and progressive atrophic rhinitis. Fifty of 428 herds were sampled once. B hyodysenteriae was not isolated from any of them, but B intermedia, B pilosicoli and Brachyspira group III were isolated from five, 14 and 37 of the herds, respectively. The detection of Brachyspira species did not relate to the prevalence of diarrhoea in the herds, as judged by the farmers. The herds using carbadox (40 to 50 ppm) had a lower prevalence of Brachyspira species than those using olaquindox (40 to 50 ppm).  相似文献   

13.
Rapid identification of porcine Brachyspira species is required in order to differentiate pathogenic from non-pathogenic species. The aim of our study was to compare a recently described genetic method based on polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP), nox RFLP-PCR assay, and three species-specific PCRs described previously in the literature with a 16S rRNA gene RFLP-PCR discriminatory reference assay (16S RFLP-PCR) for the identification of Brachyspira spp. of swine origin. In this study, 20 porcine spirochaetal strains were identified and compared to 33 reference strains by 16S RFLP-PCR and nox RFLP-PCR and three species-specific PCRs. RFLP-PCR methods showed concordant results for 47 strains and discordances for 6 strains (2 differently identified and 4 not revealed by nox RFLP-PCR). In our hands species-specific PCRs showed concordant results with 16S and nox RFLP-PCR for 43 strains and discordances for 10 strains (2 differently identified and 8 not amplified). The same results observed testing the 20 field-isolated spirochaetes were obtained for the corresponding porcine faecal samples. The detection limit was 10(2) -10(3) cells/g of faeces for 16S rRNA gene PCR and 10(4) cells/g of faeces for nox PCR. In our experience nox RFLP-PCR appeared successful for the speciation of B. hyodysenteriae reserving 16S RFLP-PCR for all other pathogenic and non-pathogenic Brachyspira species. Among the species-specific PCR assays tested only that for B. pilosicoli was useful in our hands.  相似文献   

14.
The antigenic properties of Brachyspira (B.) alvinipulli ATCC 51933 and strain C2 were analyzed and compared with those of B. hyodysenteriae ATCC 27164 and ATCC 31212, B. pilosicoli ATCC 51139, B. innocens ATCC 29796 and B. aalborgi NCTC 11492. In gel immunodiffusion tests, a protein in B. alvinipulli ATCC 51933 reacted strongly with anti-B. alvinipulli ATCC 51933-serum and formed two precipitin lines. Furthermore, by an immunoblotting technique, the 105-kilodaltons (kDa) protein in B. alvinipulli ATCC 51933 reacted strongly with each of the antisera to B. hyodysenteriae, B. pilosicoli, B. innocens and B. aalborgi. Therefore, the 105-kDa protein could be applied to diagnosis of chicken infection by B. alvinipulli and B. pilosicoli. But the 105-kDa protein reacting with the anti-B. alvinipulli ATCC 51933-serum was not confirmed in B. hyodysenteriae, B. pilosicoli, B. innocens and B. aalborgi. The N-terminal amino acid sequence of the 105-kDa protein isolated from B. alvinipulli ATCC 51933 was Met-Lys-Lys-Met-Val-Tyr-Phe-Phe-Gly-Asn. The amino acid alignment of this protein possessed 50% homology with the periplasmic-iron-binding protein BitC in B. hyodysenteriae.  相似文献   

15.
Pathogenic intestinal spirochaetes of pigs include Brachyspira (formerly Serpulina) hyodysenteriae, the cause of swine dysentery, and Brachyspira pilosicoli, the cause of porcine colonic spirochetosis (PCS). The purpose of this study was to assess the relative importance of Brachyspira species in diarrhoeal disease of growing pigs on farms in southern Brazil. The intensity and pattern of haemolysis, the production of indole and the hydrolysis of hippurate by reference and field porcine intestinal spirochaetes were compared with 16S-ribosomal RNA (mRNA)- and 23S-rRNA-based polymerase chain reaction assays for the identification of B hyodysenteriae and B pilosicoli. Between July and October 1998, 206 rectal swabs were taken from pigs on 17 farms with a history of diarrhoea developing within 30 days after they had been moved from nursery to growing facilities. Of 49 beta-haemolytic spirochaetes that were cultured, 29 (59.2 per cent) were grown in pure culture for phenotypic and genotypic characterisation, leaving 20 untyped. Of the 29 typed isolates, eight isolates obtained from six farms were identified as B hyodysenteriae, and 15 isolates obtained from seven other farms were identified as B pilosicoli; the remaining six isolates were identified as weakly beta-haemolytic commensal spirochaetes. There was complete agreement between the results of the phenotypic and genotypic analyses.  相似文献   

16.
The aim of this study was to obtain prevalence estimates about the most important enteropathogenic bacteria: Lawsonia intracellularis, Brachyspira hyodysenteriae, Brachyspira pilosicoli, Salmonella enterica and Clostridium perfringens A and C in Hungarian farrow-to-finish pig herds. A total of 31 herds were selected, from where six pooled faecal samples, each containing three individual rectal faecal samples were collected from fattening pigs of 5-6 months of age. All 186 samples were examined by polymerase chain reaction (PCR) for the presence of the pathogens mentioned above. Lawsonia intracellularis was found in 29 herds (93.55%) and in 108 samples (58.06%); B. hyodysenteriae in 14 herds (45.16%) and in 23 samples (12.37%); B. pilosicoli in 19 herds (61.29%) and in 53 samples (28.49%); S. enterica in 17 herds (54.83%) and in 40 samples (21.50%). We detected the presence of C. perfringens A in 19 herds (61.29%) and in 46 samples (24.73%), while C. perfringens C was found in 8 herds (25.81%) and in 11 samples (5.91%). All examined herds were infected with one or more of these agents. Herds with diarrhoea in the mid- to late finishing phase had almost 10 times higher prevalence of B. hyodysenteriae than herds without such a history.  相似文献   

17.
The purpose of this study was to determine whether methods used to control swine dysentery (SD), caused by the intestinal spirochaete Brachyspira (Serpulina) hyodysenteriae, would also be effective in controlling porcine intestinal spirochaetosis (PIS) caused by the related spirochaete Brachyspira (Serpulina) pilosicoli. Weaner pigs in Groups I (n=8) and II (n=6) received a standard weaner pig diet based on wheat and lupins, whilst Group III (n=6) received an experimental diet based on cooked white rice and animal protein. Pigs in Group II were vaccinated intramuscularly twice at a 3-week-interval with a formalinised bacterin made from B. pilosicoli porcine strain 95/1000 resuspended in Freund's incomplete adjuvant. Eleven days later pigs in all groups were infected orally with 10(10) cells of strain 95/1000 on three successive days. One control pig in Group I developed acute diarrhoea, and at post-mortem had a severe erosive colitis with end-on attachment of spirochaetes to the colonic epithelium. All other pigs developed transient mild diarrhoea and had moderate patchy colitis at post-mortem 3 weeks later. B. pilosicoli was isolated from the faeces of all pigs, except for one fed rice, and was isolated from the mesenteric nodes of three pigs from Group I and from one vaccinated pig in Group II. Consumption of the rice-based diet, but not vaccination, delayed and significantly (p<0.001) reduced the onset of faecal excretion of B. pilosicoli after experimental challenge. Vaccination induced a primary and secondary serological response to B. pilosicoli, as measured using sonicated whole cells of strain 95/1000 as an ELISA plate coating antigen. Antibody titres in the vaccinated pigs then declined, despite intestinal colonisation by B. pilosicoli. Both groups of unvaccinated animals also failed to develop a post-infection increase in circulating antibody titres.  相似文献   

18.
Brachyspira infections are significant causes of enterocolitis in pigs. In order to differentiate pathogenic species (Brachyspira (Br.) hyodysenteriae, Brachyspira pilosicoli) from less pathogenic or non-pathogenic species (Brachyspira intermedia, Brachyspira innocens, Brachyspira murdochii) in paraffin-embedded tissue samples a polymerase chain reaction (PCR) protocol allowing identification of Brachyspira at species level in archival material was developed. This approach was complemented by sequencing of the PCR amplification products. All seven cases presented with clinical and morphological Brachyspira-associated enterocolitis. Br. hyodysenteriae was not identified in any of the cases, while Br. pilosicoli was identified in a single case in conjunction with Br. murdochii. One case each was found positive for Br. innocens and Br. intermedia. Interestingly, the majority of cases presented as single or double infections with Br. murdochii. In some of the pigs other pathogens, like porcine circovirus-2 or Lawsonia intracellularis were present. These observations point at the possibility that under certain conditions even Brachyspira species of low pathogenicity can multiplicate extensively and lead to Brachyspira-associated enterocolitis.  相似文献   

19.
VSH-1 is an unusual prophage-like gene transfer agent (GTA) that has been described in the intestinal spirochaete Brachyspira hyodysenteriae. The GTA does not self-propagate, but it assembles into a virus-like particle and transfers random 7.5kb fragments of host DNA to other B. hyodysenteriae cells. To date the GTA VSH-1 has only been analysed in B. hyodysenteriae strain B204, in which 11 late function genes encoding prophage capsid, tail and lysis elements have been described. The aim of the current study was to look for these 11 genes in the near-complete genomes of B. hyodysenteriae WA1, B. pilosicoli 95/1000 and B. intermedia HB60. All 11 genes were found in the three new strains. The GTA genes in WA1 and 95/1000 were contiguous, whilst some of those in HB60 were not-although in all three strains some gene rearrangements were present. A new predicted open reading frame with potential functional importance was found in a consistent position associated with all four GTAs, located between the genes for head protein Hvp24 and tail protein Hvp53, overlapping with the hvp24 sequence. Differences in the nucleotide and predicted amino acid sequences of the GTA genes in the spirochaete strains were consistent with the overall genetic distances between the strains. Hence the GTAs in the two B. hyodysenteriae strains were considered to be strain specific variants, and were designated GTA/Bh-B204 and GTA/Bh-WA1 respectively. The GTAs in the strains of B. intermedia and B. pilosicoli were designated GTA/Bint-HB60 and GTA/Bp-95/1000 respectively. Further work is required to determine the extent to which these GTAs can transfer host genes between different Brachyspira species and strains.  相似文献   

20.
The objective of this investigation was to identify risk factors for infection with the intestinal bacteria: Lawsonia intracellularis, Brachyspira hyodysenteriae, Serpulina intermedia, Brachyspira innocens, Brachyspira pilosicoli and swine-pathogenic Escherichia coli (serogroups O138, O139, O141 and O149) in Danish finishing pig herds.A total of 79 herds was randomly selected and visited during 1998. From each herd, 20 faecal samples were collected from individual pigs weighing 30-50 kg. In total, 1580 faecal samples were collected and examined by polymerase chain reaction (L. intracellularis) or culture (all other agents). Information on feed and management procedures was collected by filling in questionnaires at the herd visits. The questionnaires included information on 29 dichotomous variables and three continuous variables. Variables with P<0.25 in a preliminary screening (chi2- or t-test) were selected for the statistical modelling.Our conclusions, based on the results of multifactorial logistic regression (cut-off: P=0.05), were the following: 1. Consistent batch production was associated with reduced prevalences of L. intracellularis and weakly -haemolytic spirochetes (S. intermedia, B. innocens, B. pilosicoli) (OR's=0.43 and 0.06, respectively). 2. Home-mixed (and/or non-pelleted) feed was associated with reduced prevalences of L. intracellularis and weakly -haemolytic spirochetes (OR's=0.6 and 0.4, respectively). 3. Providing straw to finishers was associated with a reduced prevalence of weakly -haemolytic spirochetes (OR=0.28-0.32). 4. Not using antimicrobial growth promoters for piglets was associated with an increased prevalence of S. intermedia (OR=11.11). 5. Rare occurrence of post-weaning diarrhoea (as opposed to common) was associated with an increased prevalence of weakly -haemolytic spirochetes (OR=8.3-13.7).  相似文献   

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