Antimicrobial Susceptibility and Genomic Structure of Arcobacter skirrowii Isolates

Campylobacter spp. are considered the most common bacterial cause of foodborne gastroenteritis in the world. The family Campylobacteraceae includes the genus Arcobacter with the three species Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii as emergent enteropathogens and potential zoonotic agents. Here, we characterized genome sequences of Arcobacter that were isolated from water poultry on farms in Germany. Isolates were cultured, identified by MALDI-TOF MS and identification was verified with PCR assays. Antibiotic susceptibility testing of isolates was carried out with erythromycin, ciprofloxacin, doxycycline, tetracycline, gentamicin, and streptomycin using the gradient strip method (E-test). We also sequenced whole genomes and predicted antibiotic resistance determinants, virulence factors, performed a phylogenetic analysis to determine the genetic relatedness of these isolates and searched for plasmids

Aliarcobacter butzleri from Water Poultry: Insights into Antimicrobial Resistance, Virulence and Heavy Metal Resistance

Aliarcobacter butzleri is the most prevalent Aliarcobacter species and has been isolated from a wide variety of sources. This species is an emerging foodborne and zoonotic pathogen because the bacteria can be transmitted by contaminated food or water and can cause acute enteritis in humans. Currently, there is no database to identify antimicrobial/heavy metal resistance and virulence-associated genes specific for A. butzleri. The aim of this study was to investigate the antimicrobial susceptibility and resistance profile of two A. butzleri isolates from Muscovy ducks (Cairina moschata) reared on a water poultry farm in Thuringia, Germany, and to create a database to fill this capability gap. The taxonomic classification revealed that the isolates belong to the Aliarcobacter gen. nov. as A. butzleri comb. nov. The antibiotic susceptibility was determined using the gradient strip method. While one of the isolates was resistant to five antibiotics, the other isolate was resistant to only two antibiotics. The presence of antimicrobial/heavy metal resistance genes and virulence determinants was determined using two custom-made databases. The custom-made databases identified a large repertoire of potential resistance and virulence-associated genes. This study provides the first resistance and virulence determinants database for A. butzleri

Expression patterns and role of the CadF protein in Campylobacter jejuni and Campylobacter coli

Binding of Campylobacter jejuni and Campylobacter coli to host fibronectin is mediated by the 37 kDa outer membrane protein CadF. Immunoblot analysis of 58 C. jejuni and C. coli isolates of human and animal origin showed that CadF is expressed in every strain. In most C. jejuni isolates, a 37 kDa band (p37) and a less-prominent 32 kDa band (p32) reacted with the antibodies. In C. coli isolates, CadF was consistently larger with sizes of 39 kDa (p39) and 34 kDa (p34), respectively. PCR analysis and sequencing revealed the presence of a 39-bp insertion sequence in the cadF gene of C. coli strains, explaining the increased molecular size. Infection assays revealed that C. jejuni bound and invaded INT-407 epithelial cells much more efficiently than C. coli and that this difference was considerably reduced in isogenic cadF mutants. These results demonstrate that CadF is an important pathogenicity factor. The difference between CadF of C. jejuni and C. coli may potentially be exploited to discriminate these species in food and clinical specimens