Prevalence and genetic characterization of Campylobacter from clinical poultry cases in China

Abstract

ABSTRACT Campylobacter is one of the leading causes of bacterial foodborne diseases globally. Poultry is considered a major reservoir for the transmission of Campylobacter to humans. The occurrence and epidemiology of Campylobacter in healthy poultry have been extensively studied, but the prevalence in diseased poultry has rarely been reported. In this study, a total of 1,563 intestinal samples, 547 gallbladder samples, and 3,729 parenchyma organ samples were collected from diseased chickens, ducks, and geese in Yangzhou Veterinary Hospital between December 2016 and September 2017. The bacterial isolates were analyzed for genotype, resistance, and virulence genes. The overall prevalence of Campylobacter was 17.9%, and a significantly higher prevalence was observed in the diseased chickens (21.8%) than in the diseased ducks (12.1%) and geese (11.9%). Campylobacter was significantly more prevalent in the intestinal tract (39.6%), followed by the gallbladder (11.7%) and parenchyma organ (9.7%). Among 84 whole-genome sequenced Campylobacter isolates, we identified 47 multi-locus sequence typing types, of which ST-51 and ST-825 were the most predominant sequence types (STs) for Campylobacter jejuni and Campylobacter coli , respectively. Phylogenetic analysis showed that Campylobacter isolates from different tissues from the same host tended to cluster together with the same STs, which indicated Campylobacter infection in different tissues in vivo . The antimicrobial resistance genes most frequently identified were gyrA (T86I) (97.6%) and tet (O) (65.5%). Our results revealed the high prevalence of Campylobacter in diseased poultry in China, which will help the farms take the necessary action to develop effective mitigation strategies for reducing Campylobacter infection in poultry. IMPORTANCE Campylobacter is a major cause of campylobacteriosis worldwide, and poultry is the main reservoir for its transmission. Campylobacter was generally considered to be a harmless commensal organism in poultry without pathogenic properties. However, it was proposed that a Campylobacter -like organism may be the cause of vibrionic hepatitis, which poses a significant public health risk. The occurrence and epidemiology of Campylobacter in healthy poultry have been studied systematically, but little is known about the epidemiology of Campylobacter isolates from diseased poultry in China. Therefore, this study determined the prevalence and molecular characterization of Campylobacter from diseased chickens, ducks, and geese in Yangzhou Veterinary Hospital between December 2016 and September 2017, which was critical for improving the diagnosis and prevention of Campylobacter infections.