Brachyspira hyodysenteriae isolated from apparently healthy pig herds following an evaluation of a prototype commercial serological ELISA

Hampson, David J.; La, Tom; Phillips, Nyree D.; Holyoake, P. K.

doi:10.1016/j.vetmic.2016.05.016

Cited by 15 publications

(26 citation statements)

References 29 publications

(2 reference statements)

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“…These included breeding herds that underwent heightened surveillance as part of this study, including collection of colonic mucosa from healthy pigs at the abattoir. Results for six of these herds that were initially identified as infected through serological screening have been reported previously [15]. A similar situation was reported in an early Australian study, where an isolate of B .…”

Section: Discussionsupporting

confidence: 74%

“…Besides hemolysis, the block of six plasmid genes may encode other potential virulence factors that have been loosely associated with facilitating colonization [15,24,53]. Analysis of the distribution of this block of genes showed that most of the STs in the herds that were either thought to be free of SD or where the disease status was unclear did lack them, but this also commonly was the case for the isolates in STs in the herds with a history of SD (Table 4).…”

Section: Discussionmentioning

confidence: 99%

“…In Australia, B . hyodysenteriae has been isolated from apparently healthy herds that gave what were initially thought to be false positive results in a serological ELISA [15]. …”

Section: Introductionmentioning

confidence: 99%

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An Investigation into the Etiological Agents of Swine Dysentery in Australian Pig Herds

Phillips

Hampson

2016

PLoS ONE

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Swine dysentery (SD) is a mucohemorrhagic colitis, classically seen in grower/finisher pigs and caused by infection with the anaerobic intestinal spirochete Brachyspira hyodysenteriae. More recently, however, the newly described species Brachyspira hampsonii and Brachyspira suanatina have been identified as causing SD in North America and/or Europe. Furthermore, there have been occasions where strains of B. hyodysenteriae have been recovered from healthy pigs, including in multiplier herds with high health status. This study investigated whether cases of SD in Australia may be caused by the newly described species; how isolates of B. hyodysenteriae recovered from healthy herds compared to isolates from herds with disease; and how contemporary isolates compare to those recovered in previous decades, including in their plasmid gene content and antimicrobial resistance profiles. In total 1103 fecal and colon samples from pigs in 97 Australian herds were collected and tested. Of the agents of SD only B. hyodysenteriae was found, being present in 34 (35.1%) of the herds, including in 14 of 24 (58%) herds that had been considered to be free of SD. Multilocus sequence typing applied to 96 isolates from 30 herds and to 53 Australian isolates dating from the 1980s through the early 2000s showed that they were diverse, distinct from those reported in other countries, and that the 2014/16 isolates generally were different from those from earlier decades. These findings provided evidence for ongoing evolution of B. hyodysenteriae strains in Australia. In seven of the 20 herds where multiple isolates were available, two to four different sequence types (STs) were identified. Isolates with the same STs also were found in some herds with epidemiological links. Analysis of a block of six plasmid virulence-associated genes showed a lack of consistency between their presence or absence and their origin from herds currently with or without disease; however, significantly fewer isolates from the 2000s and from 2014/16 had this block of genes compared to isolates from the 1980s and 1990s. It is speculated that loss of these genes may have been responsible for the occurrence of milder disease occurring in recent years. In addition, fewer isolates from 2014/16 were susceptible to the antimicrobials lincomycin, and to a lesser extent tiamulin, than those from earlier Australian studies. Four distinct multi-drug resistant strains were identified in five herds, posing a threat to disease control.

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Section: Discussionsupporting

confidence: 74%

Section: Discussionmentioning

confidence: 99%

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An Investigation into the Etiological Agents of Swine Dysentery in Australian Pig Herds

Phillips

Hampson

2016

PLoS ONE

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“…It is known that healthy pigs in some herds without disease may carry low numbers of virulent B. hyodysenteriae in their large intestines . The lack of a complete bacteriological ‘cure’ at the dose rates of kitasamycin used in this experiment is a potential drawback, since these treated animals potentially still will be infectious.…”

Section: Discussionmentioning

confidence: 99%

Testing the efficacy of kitasamycin for use in the control and treatment of swine dysentery in experimentally infected pigs

Phillips

Dunlop³

et al. 2019

Aust Veterinary J

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Background Swine dysentery (SD) caused by Brachyspira hyodysenteriae is an important disease in Australia. Aim The aim of this study is to evaluate the macrolide antibiotic kitasamycin for use in SD control. Methods The minimum inhibitory concentrations (MICs) of kitasamycin, tylosin and lincomycin for 32 Australian isolates of B. hyodysenteriae were evaluated. Mutations in the 23S rRNA gene were examined. Isolate ‘13’ with a low kitasamycin MIC was used to challenge weaner pigs. Sixty pigs were housed in 20 pens each containing three pigs: pigs in four pens received 2 kg/tonne of a product containing kitasamycin (3.1% active) prophylactically in their food starting 4 days before B. hyodysenteriae challenge (group 1); pigs in four pens were challenged and received the same dose therapeutically once one pig in a pen showed diarrhoea (group 2); four pens were challenged and received 4 kg/tonne of the product therapeutically (group 3); four pens were challenged but not medicated (group 4); two pens were unmedicated and unchallenged (group 5) and two pens received 2 kg/tonne and were unchallenged (group 6). Pigs were monitored for B. hyodysenteriae excretion and disease. Results Macrolide resistance was widespread, and mutations in the 23S rRNA gene were identified in 23 isolates. Four isolates with kitasamycin MICs < 5 μg/mL were considered susceptible. Following experimental challenge, 10 of 12 unmedicated pigs developed SD. No pigs receiving kitasamycin prophylactical or therapeutically developed SD. Medicated pigs shed low numbers of B. hyodysenteriae in their faeces. Conclusions Kitasamycin can help control SD in pigs infected with susceptible isolates of B. hyodysenteriae.

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“…The etiological agent of SD is the anaerobic intestinal spirochaete Brachyspira hyodysenteriae [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

The Efficacy of Two Phytogenic Feed Additives in the Control of Swine Dysentery

et al. 2018

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Control of swine dysentery with antibiotics is often ineffective due to the resistance of Brachyspira hyodysenteriae. The potential of some herbal-based components against B. hyodysenteriae was previously studied in vitro. This study aims at the evaluation of in vivo effi cacy of phytogenic feed additives in the control of swine dysenteryThe study involved 64 seven-week old weaned pigs allotted to 4 groups: two were fed on feed supplemented with either Patente Herba® or Patente Herba® Plus, the third received tiamulin (positive control), while the negative control was not given antibiotics or additives. Fecal consistency was recorded daily. The presence of B. hyodysenteriae in the feces was investigated weekly using microbiological assays and the PCR test. Weight gain and feed conversion ratio were calculated for each week, and for the whole experiment.B. hyodysenteriae was detected in all samples by both methods. The additives showed effi cacy in the prevention and control of swine dysentery as only normal and soft stool was observed in the treated groups. By contrast, in the negative control all feces categories were detected. Frequencies of feces categories signifi cantly differed (p<0.001) between feed-supplemented groups and the negative control. Effi cacy of both additives in the prevention of SD is comparable to tiamulin, based on insignifi cant differences in the frequency of the various feces categories.Benefi cial effects of both additives resulted in signifi cantly (p≤0.05) higher weight gain and lower feed conversion ratio in comparison to the negative control. The average weight gains between additive-fed groups and tiamulin-treated group did not differ signifi cantly.

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Brachyspira hyodysenteriae isolated from apparently healthy pig herds following an evaluation of a prototype commercial serological ELISA

Cited by 15 publications

References 29 publications

An Investigation into the Etiological Agents of Swine Dysentery in Australian Pig Herds

An Investigation into the Etiological Agents of Swine Dysentery in Australian Pig Herds

Testing the efficacy of kitasamycin for use in the control and treatment of swine dysentery in experimentally infected pigs

The Efficacy of Two Phytogenic Feed Additives in the Control of Swine Dysentery

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