Genetic instability is associated with changes in the colonization potential ofCampylobacter jejuniin the avian intestine

Abstract

Aims: A panel of pulsed field gel electrophoresis (PFGE) type variants of Campylobacter jejuni, previously identified as of clonal origin, were investigated to determine whether genomic instability could be observed during competitive growth. Methods and Results: Upon recovery from frozen storage, some variants had undergone alterations in PFGE profiles, but subsequent culture produced constant genotypes. Individual variants did not display differences in colonization potential when tested in orally challenged 1‐day‐old chickens. However, competitive colonization using mixtures of two or three PFGE types generally resulted, by 4 weeks postchallenge, in one predominant PFGE type in all birds. For some variant mixtures, a minor population of novel PFGE types was detected in individual birds. The creation of new variants appeared to be dependent on the extent of competition and of the individual host. Genomic rearrangements most likely explain this increase in genetic diversity, apparently without the involvement of natural transformation or plasmid acquisition. In vitro cultivation of mixed inoculations were again selected for particular variants; but genetic diversity was not generated, suggesting that the selection pressures in vitro differed from those active in vivo. Conclusion: These observations support the hypothesis that by generating genetic diversity, C. jejuni can improve its phenotypic fitness to survive and colonize subsequent hosts. Significance and Impact of the Study: The consequences of such observations for the development of campylobacter control strategies for poultry may be substantial.

Campylobacteriosis: an emerging zoonosis, underdiagnosed and underreported by public health agencies in Brazil

“…Rastall (2004) investigated alternative antibiotics sources for campylobacteriosis treatment and found that the use of a probiotic (Lactobacillus acidophilus) together with a prebiotic (fructooligosaccharides, and lactosucrose) showed positive effects on the balance of intestinal microflora, an there was an improvement in recovery from infection and immune status. This balance of microflora occurs by competitive exclusion of pathogens after the use of probiotics (RINKINEN, 2003).…”

“…is a zoonosis of worldwide distribution, with serious implications for public health and a significant socio-economic impact (EFSA, 2009). The high incidence of campylobacteriosis has become the most commonly cause of gastrointestinal disease reported worldwide (RIDLEY et al, 2008).…”

“…jejuni is present in the intestinal tract of birds and mammals, including production and pet animals, being the cause of enteritis in young animals, including cattle, poultry, pigs, cats and dogs (GOMES, 2012) besides being the most prevalent species in human infections (RIDLEY et al, 2008).…”

“…From the Campylobacter species identified, the most implicated in outbreaks of gastrointestinal disease are C. jejuni and C. coli, being recognized as the most important and with greater pathogenic potential from the viewpoint of food safety (RIDLEY et al, 2008). C. upsaliensis is also considered an important cause of gastroenteritis in humans, but its true incidence is underestimated by conventional culture methods, because this species is inhibited by the antibiotics used in the culture medium for the isolation of other Campylobacter species (MURRAY et al, 2009).…”

Functional Analysis of the RdxA and RdxB Nitroreductases of Campylobacter jejuni Reveals that Mutations in rdxA Confer Metronidazole Resistance

“…Loss of MMR would presumably contribute to some mutations, such as point and small frameshift mutations, within rdxA, causing Mtz r . The lack of MMR may also contribute to a high degree of phase and antigenic variation of important virulence and colonization factors, such as lipooligosaccharide (LOS) glycosylation, capsule production, and flagellar motility (7,12,36,42,44,51,52). Recently we identified flgS and flgR, encoding the sensor kinase and response regulator of a twocomponent system required for expression of 54 -dependent flagellar genes, as two genes undergoing phase variation (15,16).…”