Occurrence, genetic diversity and antibiotic resistance of Arcobacter sp. in a dairy plant

Aims: The aim of this study was to evaluate the occurrence, diversity and resistance to antibiotics of Arcobacter sp. in a dairy plant samples. Methods and Results: A total of 75 samples from dairy plant surfaces and materials and several food products collected in different steps of the cheese production process were analysed by culture, under aerobic and microaerobic atmospheric conditions, and by enrichment molecular detection. Isolates were identified and genotyped by ERIC-PCR, and their susceptibility to nine antibiotics was evaluated by agar dilution. Global prevalence of Arcobacter sp. was 42 7%, where 20 of the 42 food samples analysed were positive for A. butzleri by both culture and molecular detection, one for A. marinus by culture and one for A. cryaerophilus by molecular detection only; 10 of the 30 analysed materials and plant surfaces were positive for A. butzleri. All A. butzleri isolates were resistant to nalidixic acid and showed high resistance rates to ampicillin (56 2%) and cefotaxime (97 9%), being all strains susceptible to gentamicin and erythromycin. Conclusions: Contamination of dairy plant environment with A. butzleri and its progression along cheese production process were observed, however, the cheese ripening process may have a relevant role in the reduction of the contamination. Significance and Impact of the Study: This study showed the presence of Arcobacter sp. in a dairy plant, displaying its high prevalence and genetic diversity and highlighting its high resistance rates. The data obtained could contribute to further acknowledge the Arcobacter food contamination as a potential health hazard.Susana Ferreira was supported by a fellowship (SFRH/BPD/101959/2014) from FCT—Foundation for Science and Technology and co-financed by European Social Fund. This work was supported by FEDER funds through the POCI—COMPETE 2020—Operational Programme Competitiveness and Internationalisation in Axis I — Strengthening research, technological development and innovation (Project POCI-01-0145-FEDER-007491) and National Funds by FCT—Foundation for Science and Technology (Project UID/Multi /00709/2013). Capillary sequencing was performed at Unidade de Tecnologia e Inovação (Departamento de Genetica Humana, Instituto Nacional de Saude Dr Ricardo Jorge, Lisbon, Portugal).