Prevalence, Population Diversity and Antimicrobial Resistance of Campylobacter coli Isolated in Italian Swine at Slaughterhouse.

Guido Di Donato,Daria Di Sabatino,Katiuscia Zilli,Paolo Calistri,Roberta Nuvoloni,Francesca Marotta,Elisabetta Di Giannatale,Diana Neri

doi:10.3390/microorganisms8020222

Abstract

Campylobacter spp. are among the microorganisms most commonly associated with foodborne disease. Swine are known to be the main reservoir of Campylobacter coli and a possible source infection of humans as a result of carcass contamination at slaughter. The aim of this study was to evaluate the prevalence of C. coli contamination in swine carcasses, the antimicrobial resistance (AMR) patterns of isolates and the genetic diversity between strains obtained from swine and those isolated from humans. The prevalence of contamination was higher on carcasses (50.4%) than in faeces (32.9%). The 162 C. coli isolated from swine were examined by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). The results of PFGE indicated a high genetic diversity among the isolates, with 25 different PFGE types. MLST assigned 51 sequence types (STs) to isolates. The most common genotype was ST-854 (16.04%), ST-9264 (10.49 %) and ST-1016 (6.08 %). Results of AMR showed a high resistance to quinolones and fluoroquinolones together with aminoglycosides and tetracycline. Many strains were multi-resistant with predominant R-type TeSCipNa (57%). Five resistance genes were detected along with mutation in the gyrA gene. A strong correlation between phenotypic and genotypic resistance was found for fluoroquinolone and tetracycline. Genetic profiles obtained in swine isolates were compared to those of 11 human strains. All human strains and 64.19% of animal strains (104/162) were assigned to the ST-828 clonal complex.

Highlights

Campylobacter spp. are among the most common causes of bacterial diarrhoea worldwide and are estimated to cause approximately 246,000 illnesses annually in the European Union (EU), mostly due to consumption of contaminated food [1]
The species most commonly associated with human infection are Campylobacter jejuni followed by Campylobacter coli and Campylobacter lari, other Campylobacter species, including the non-thermophilic Campylobacter fetus, are known to occasionally cause human infection [1]
All positive animals were contaminated with C. coli, and three animals were positive for C. jejuni

Summary

Introduction

Campylobacter spp. are among the most common causes of bacterial diarrhoea worldwide and are estimated to cause approximately 246,000 illnesses annually in the European Union (EU), mostly due to consumption of contaminated food [1]. Campylobacter may be transferred to humans indirectly through the ingestion of contaminated water or food [2] and less frequently by direct contact with contaminated animals or animal carcasses. C. jejuni is considered the most frequent Campylobacter species associated with disease in humans, and are responsible for about 80%–90% of the total number of human cases of campylobacteriosis in the EU [1]. In the EU, C. coli has been found to be responsible for about 9% of human campylobacteriosis in the EU. Food producing animals like poultry, cattle and swine are common hosts and important reservoirs of Campylobacter species. C. jejuni is considered prevalent in poultry [5] and cattle [6], while pigs are mostly implicated as reservoirs of C. coli [7]

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