Spirochaetes as intestinal pathogens: Lessons from a Brachyspira genome

Abstract

Anaerobic spirochaetes of the genus Brachyspira have long been known as important gut pathogens of pigs, but increasingly they are recognised as causing disease in birds and other animal species, including human beings. The genome sequence of the major swine pathogen Brachyspira hyodysenteriae was recently published, and this revealed extensive genome optimisation that leads to adaptation to the complex environment of the colon. The genome sequences of other pathogenic and non-pathogenic Brachyspira species are becoming available, and this data will help to reveal how these species have evolved and adapted to varied lifestyles in the large intestines of different species, and why some but not others can induce colitis and diarrhoea.

Species characterization and minimum inhibitory concentration patterns of Brachyspira species isolates from swine with clinical disease

“…American Type Culture Collection (ATTC) strains B. hyodysenteriae B204 (#31212) and B. pilosicoli P43/6/78 (#51139) were used as quality control organisms for agar MIC testing as previously described. 5,10,18 Isolates were tested in duplicate; any isolate with MIC values greater than 2 antibiotic dilutions different from one another in replicates were tested a third time to obtain a consensus MIC value.…”

“…Additionally, a prophage-like gene transfer agent (VSH-1) capable of moving 7,500 base-pair segments between strains of this species has been described. 2,5 Similar sequences that may encode for mobile genetic elements have been identified in other Brachyspira species. 2 Changes in phenotypic behavior in vitro and the association with clinical disease in vivo may indicate that DNA transfer between Brachyspira species is also possible.…”

“…have been associated with clinical disease in other species, including birds, dogs, and human beings; zoonotic potential could be an important consideration in Brachyspira risk assessments. 3,5 Further research into virulence gene prevalence and monitoring of clinical Brachyspira spp. isolates will be useful in more definitive characterization of this disease complex.…”

Minimum inhibitory concentration of Brazilian Brachyspira hyodysenteriae strains

“…The second is horizontal achievement via a bacteriophage known as VSH-1. This bacteriophage is important in gene transfer between its host cells and can contribute to genetic changes in strains through the transduction of new gene sequences between species or Brachyspira strains (Humphrey et al 1997, Bellgard et al 2009, Hampson & Ahmed 2009). These changes may alter phenotypic properties, potentially modifying antimicrobial susceptibility, colonization or virulence (Duhamel 2011).…”

A review of the current state of antimicrobial susceptibility test methods forBrachyspira

“…Brachyspira is a genus of Gram-negative, oxygen-tolerant anaerobic spirochetes that colonize the intestinal tracts of wild and domestic animals and humans (Hampson and Ahmed 2009). Seven species with standing in nomenclature are currently recognized within the genus Brachyspira, including the causative agents of swine dysentery and porcine, avian, and human intestinal spirochetosis.…”