Serologic detection ofBrachyspira (Serpulina) hyodysenteriaeinfections

Abstract

Swine dysentery (SD) caused by the intestinal spirochete Brachyspira hyodysenteriae is an economically important disease in pig-producing countries throughout the world. To date, no specific serologic assay is commercially available for the diagnosis of pigs with SD. Several serologic techniques have been identified in the past; however, these tests have all used either whole-cell proteins or lipopolysaccharide (LPS) as the antigen. Whole-cell antigens are plagued with false-positive reactions due to cross-reactivity with common proteins shared with other spirochetes. LPS antigens produce fewer false-positives; however, false-negatives may result due to LPS components being serogroup-specific. Generally, these techniques are useful for detecting infected herds, but are unreliable for the detection of individual infected pigs. In order to develop improved serologic tests it will be necessary to identify suitable diagnostic antigens, in particular immunogenic cell-surface structures which are specific to B. hyodysenteriae but common amongst different strains of the species. Recently, we identified and cloned a 30-kDa outer membrane lipoprotein (BmpB) which is specific to B. hyodysenteriae and is recognized by experimentally and naturally infected pigs. In this review we summarize the available serologic tests for SD, and speculate on the use of recombinant BmpB as an antigen for future development of an improved serologic test for SD diagnosis.

The use of ELISAs for monitoring exposure of pig herds to Brachyspira hyodysenteriae

“…B. hyodysenteriae WC preparations have been thought to potentially generate false positive results arising from cross-reactivities associated with exposure to other Brachyspira species, or other bacteria with cross-reactive proteins [5,7]. In the pigs from the cohort on farm A, where SD did not occur, there was no significant temporal change in IgG levels to the B. hyodysenteriae WC preparation, but there were significant increases to WC preparations from both B. pilosicoli and B. innocens .…”

“…Diagnosis is usually based on clinical signs and detection of the causative spirochaete by culture and/or PCR [2-4]. Although not widely used, serological tests measuring serum immunoglobulins specific to B. hyodysenteriae have potential to be used at the herd level for routine surveillance [5]. ELISA systems using whole spirochaete cells [6,7], lipopolysaccharide (LPS) [8], and the B. hyodysenteriae outer membrane lipoprotein Bhlp29.7 [9] as antigens all have been described for this purpose.…”

“…Being a serogroup-specific antigen, LPS is not considered suitable for development of a universal diagnostic tool [5,11,12], and therefore it was not included in the present evaluation. The first application involved monitoring antibody profiles in growing pigs in an infected herd to assess the herd infection dynamics and predict the time of infection, and the second explored using the ELISAs on muscle fluid ("meat juice") samples taken from pigs at slaughter.…”

A Possibility of Application of the 105-Kilodaltons Protein of <i>Brachyspira alvinipulli</i> Cross-Reacting with Antisera to Five Species in the Genus <i>Brachyspira</i> to Diagnosis

“…But there are few reports on diagnostic techniques for the detection of antibodies to B. pilosicoli or B. alvinipulli in infected animals. Although polymerase chain reaction (PCR) with 16S rDNA [12] or 23S rRNA [2] is a useful tool for the identification of B. pilosicoli, it cannot detect less than 10 3 spirochete cells in the fecal samples [8]. On the other hand, PCR tests and immunological tests have never been developed for the diagnosis of B. alvinipulli [15].…”

“…A slideagglutination test has been developed to determine the serogroup of isolates of B. hyodysenteriae [5]. Moreover, a 30-kDa outer membrane lipoprotein (BmpB) which was specific to B. hyodysenteriae has been studied as a candidate for an antigen for diagnosis of swine dysentery [8]. But there are few reports on diagnostic techniques for the detection of antibodies to B. pilosicoli or B. alvinipulli in infected animals.…”