Genomic surveillance of Campylobacter in Italian poultry

Abstract P9

Presenter: Francesca Marotta (Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise G.Caporale)

Authors: Marotta F (1), Di Marcantonio L (1), Romantini R (1), Telera GC (2), Perilli M (2), Zilli K (1), Abass A (1), Janowicz A (1), Garofolo G (1)

• 1- LNR Campylobacter, Istituto Zooprofilattico Sperimentale dellAbruzzo e del Molise G. Caporale, Teramo, Italy
• 2- Sezione Diagnostica di Pescara, Istituto Zooprofilattico Sperimentale dellAbruzzo e del Molise G. Caporale,Teramo, Italy

Poultry is a natural reservoir of Campylobacter and most of the campylobacteriosis cases are attributable to the consumption of undercooked poultry or to the handling of raw meat. The persistence of this pathogen in poultry and chicken product is reported worldwide, despite the efforts employed to reducing their contamination in the farms or in the slaughterhouses environment. The aims of this study were to monitor the spread of C. jejuni and C. coli genomic variants from poultry in Italy, and to identify the circulating antibiotic resistant genes (ARGs). Whole genome sequencing (WGS) on 385 C. jejuni and 166 C. coli collected over an 8-year period (2008-2016) was performed. Genomes were screened for MLST and cgMLST by Ridom Seqsphere and analyzed by Abricate and pointFinder for AMR genes and point mutations. A comparison between phenotypic and genotypic methods for the identification of the AMR was also applied. Genotypic analyses revealed high diversity among Campylobacter strains examined. MLST displayed 68 C. jejuni STs and 39 C. coli STs. Among these, only 19.12% and 7.7% of STs resulted sharing in C.jejuni and coli population analyzed in both periods. The most common STs in C. jejuni were ST-2116, ST-50 and ST- 45, while in C. coli were ST- 832 and ST-7159. The ST-2116 occurrence was significantly associated with Italian poultry farms and has been detected since 2008 along the entire national territory. Molecular screening of AMR mechanisms revealed the predominance of gyrA T86I substitution among fluoroquinolone- and quinolone-resistant isolates in C. jejuni and C. coli. The main resistance determinants found were tet(O) gene, blaOXA184, blaOXA450, blaOXA61, blaOXA193, blaOXA605, aadE (ant(6)-Ia) and the multi-drug efflux transporter gene cmeABC. While a high genotypic-phenotypic correlation was found for tetracycline and quinolones, some resistance phenotypes could not be predicted by the presence of AMR determinants. The findings of this study highlight the genetic basis of AMR and the emergence of an internationally rare genotype among Campylobacter strains isolated from the layer poultry Italian farm. Moreover, some predominant persistent genotypes were also detected among different Italian districts.

Key Words: Campylobacter, ARGs, WGS, genotypes.

Presenting in Speaking session 3 - Epidemiology and public health