Epidemiological Association of Different Campylobacter jejuni Groups with Metabolism-Associated Genetic Markers

Abstract

In this study, multilocus sequence typing (MLST) was combined with the genetic detection of six genetic markers, ansB, dmsA, ggt, cj1585c, cjj81176-1367/71 (cj1365c), and the two-gene marker tlp7 (cj0951c plus cj0952c), to assess if their presence correlated with different C. jejuni clonal groups. Using a collection of 266 C. jejuni isolates from (in decreasing order of sample size) humans, chickens, cattle, and turkeys, it was further investigated whether the resulting genotypes correlated with the isolation source. We found combinations of the six marker genes to be mutually exclusive, and their patterns of presence or absence correlated to some degree with animal source. Together with MLST results, the obtained genotypes could be segregated into six groups. An association was identified for ansB, dmsA, and ggt with the MLST-clonal complexes (MLST-CC) 22, 42, 45, and 283, which formed the most prominent group, in which chickens were the most prevalent animal source. Two other groups, characterized by the presence of cj1585c, cjj81176-1367/71, and the two-gene marker tlp7, associated with either MLST-CC 21 or 61, were overrepresented in isolates of bovine origin. Mutually exclusive marker gene combinations were observed for ansB, dmsA, and ggt, typically found in CC 45 and the related CC 22, 42, and 283, whereas the other three marker genes were found mostly in CC 21, 48, and 206. The presence of the two-gene marker tlp7, which is typical for MLST 21 and 53 as well as for MLST-CC 61, strongly correlates with a bovine host; this is interpreted as an example of host adaptation. In cases of C. jejuni outbreaks, these genetic markers could be helpful for more effective source tracking.

Lipooligosaccharide locus class of Campylobacter jejuni: sialylation is not needed for invasive infection

“… 30 that the gene is connected to particular CCs rather than to specific hosts. In line with this, we also found that production of GGT was associated with the ST-45 CC, as found in earlier studies 30 , 31 .…”

Prevalence of virulence genes in strains of Campylobacter jejuni isolated from human, bovine and broiler

“…This may reflect differences between the C. jejuni populations in livestock in Chile and those in Finland; however, our results stress the need to confirm the results obtained using a set of C. jejuni strains from diverse geographical origins. Nevertheless, it is interesting to note that ggt -positive strains predominated in human isolates (33%) as it has been reported by other authors in Europe (Barnes et al , 2007; Gonzalez et al , 2009; Zautner et al , 2011). This is consistent with the hypothesis that C. jejuni isolates with an extended amino acid metabolism are more prevalent in humans (Gonzalez et al , 2009).…”

Variation of chemosensory receptor content of Campylobacter jejuni strains and modulation of receptor gene expression under different in vivo and in vitro growth conditions

“…Another study also showed that the presence of the interrupted reading frame is over or underrepresented in strains isolated from different sources [10]. Due to this we sequenced each tlp7 amplicon to determine if the gene was present as a full length reading frame or if it was split into two open reading frames with the introduction of a stop codon.…”