First multi-locus sequence typing scheme for Arcobacter spp.

William G Miller,Carl J Mason,Stephen Lw On,Francis Mégraud,Emma Yee,Guilin Wang,Kurt Houf,Apichai Srijan,Irene V Wesley

doi:10.1186/1471-2180-9-196

Abstract

BackgroundArcobacter spp. are a common contaminant of food and water, and some species, primarily A. butzleri and A. cryaerophilus, have been isolated increasingly from human diarrheal stool samples. Here, we describe the first Arcobacter multilocus sequence typing (MLST) method for A. butzleri, A. cryaerophilus, A. skirrowii, A. cibarius and A. thereius.ResultsA sample set of 374 arcobacters, including 275 A. butzleri, 72 A. cryaerophilus, 15 A. skirrowii and 8 A. cibarius isolates from a wide variety of geographic locations and sources, was typed in this study. Additionally, this sample set contained four strains representing a new Arcobacter species, A. thereius. The seven loci used in the four-species Arcobacter MLST method are the same as those employed previously in C. jejuni, C. coli, C. helveticus and C. fetus (i.e. aspA, atpA(uncA), glnA, gltA, glyA, pgm and tkt). A large number of alleles were identified at each locus with the majority of isolates containing a unique sequence type. All Arcobacter isolates typed in this study contain two glyA genes, one linked to lysS (glyA1) and the other linked to ada (glyA2). glyA1 was incorporated into the Arcobacter MLST method while glyA2 was not because it did not increase substantially the level of discrimination.ConclusionNo association of MLST alleles or sequence types with host or geographical source was observed with this sample set. Nevertheless, the large number of identified alleles and sequence types indicate that this MLST method will prove useful in both Arcobacter strain discrimination and in epidemiological studies of sporadic Arcobacter-related gastroenteritis. A new Arcobacter MLST database was created http://pubmlst.org/arcobacter/; allele and ST data generated in this study were deposited in this database and are available online.

Highlights

Arcobacter spp. are a common contaminant of food and water, and some species, primarily A. butzleri and A. cryaerophilus, have been isolated increasingly from human diarrheal stool samples
Development of the Arcobacter multilocus sequence typing (MLST) method was assisted by the concurrent completion of the A. butzleri strain RM4018 genome sequence [31]
The large number of MLST alleles and STs identified in this study indicates that the Arcobacter MLST method

Summary

Introduction

Arcobacter spp. are a common contaminant of food and water, and some species, primarily A. butzleri and A. cryaerophilus, have been isolated increasingly from human diarrheal stool samples. We describe the first Arcobacter multilocus sequence typing (MLST) method for A. butzleri, A. cryaerophilus, A. skirrowii, A. cibarius and A. thereius. Arcobacter spp., primarily A. butzleri and A. cryaerophilus, have been isolated from human diarrheal stool samples [18,19,20,21,22]. The presence of a subset of nonpathogenic strains alongside pathogenic strains within A. butzleri, A. cryaerophilus and perhaps the other food- and water-associated Arcobacter species, such as A. skirrowii and A. cibarius, would indicate a need for an accurate typing method to distinguish human-pathogenic and human-commensal arcobacters. Typing of Arcobacter strains using such methods as enterobacterial repetitive intergenic consensus (ERIC)-PCR, pulsed field gel electrophoresis (PFGE) and amplified fragment length polymorphism (AFLP) analysis has been reported (reviewed in [10])

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Conclusion