Genetic diversity, antimicrobial resistance, and virulence genes of thermophilic Campylobacter isolated from broiler production chain

Abstract

The aim of this study was to investigate the prevalence of thermophilic Campylobacter in the broiler production chain of southern Brazil, by evaluating broiler farms and slaughter line samples, and to determine the genetic diversity, antimicrobial resistance, and virulence genes of the isolates. Of the 140 samples investigated in this study, 75 (53.6%) were positive for thermophilic Campylobacter, and all isolates were identified by phenotypic and molecular tests as C. jejuni. The resistance to nalidixic acid was the most common (74%), followed by resistance to enrofloxacin (67.3%) and ciprofloxacin (37.1%). However, there was no resistance to the macrolides tested which are recommended for the treatment of human campylobacteriosis. The PFGE showed that the isolates were grouped in eight macrorestriction patterns (P1 to P8). A representative isolate of each macrorestriction pattern was investigated for the presence of virulence genes and all isolates carried the cadF, ciaB, cdtA, cdtB, cdtC, and flaA genes. The dnaJ gene was detected in 87.5% (7/8) of the isolates. The flhA and racR genes were detected in 75% (6/8), while the pldA gene was present in 62.5% (5/8) and the wlaN gene in 25% (2/8). The presence of C. jejuni in broiler farms and in the slaughterhouse is a hazard to consumer given that this pathogen can be maintained throughout the broiler production chain and contaminates the final product. Moreover, the presence of the major virulence genes in the isolates demonstrates that they have the ability to develop campylobacteriosis in humans.

Antimicrobial Resistance Profiles, Virulence Genes, and Genetic Diversity of Thermophilic Campylobacter Species Isolated From a Layer Poultry Farm in Korea

“…The detection rates were similar to a previous report in Korea ( Oh et al, 2017 ) but higher than those reported in South Africa and Chile ( González-Hein et al, 2013 ; Otigbu et al, 2018 ; Pillay et al, 2020 ). cad F seems to be a prerequisite for the invasion of epithelial cells by any bacterial pathogen ( Ramires et al, 2020 ). The outer membrane phospholipase A ( pld A) was observed more in C. jejuni than in C. coli ( Figure 2 ), which corroborates the study in South Africa ( Pillay et al, 2020 ), while for cia B, our findings are above those of a previous report in Korea ( Oh et al, 2017 ) and contrast with the study in South Africa ( Pillay et al, 2020 ).…”

“…The outer membrane phospholipase A ( pld A) was observed more in C. jejuni than in C. coli ( Figure 2 ), which corroborates the study in South Africa ( Pillay et al, 2020 ), while for cia B, our findings are above those of a previous report in Korea ( Oh et al, 2017 ) and contrast with the study in South Africa ( Pillay et al, 2020 ). The presence of cad F and cia B facilitates the adhesion and internalization of Campylobacter in cellular models ( Ramires et al, 2020 ). The detection rate for csr A in C. jejuni was slightly higher than the rate in C. coli , but csr A was lacking in Campylobacter strains from South Africa ( Otigbu et al, 2018 ).…”

“…Furthermore, Campylobacter can stay in feces and litter for many days, and the use of these byproducts as fertilizers would aggravate the dissemination of the pathogens ( Kassem et al, 2016 ). Campylobacter persistence in chicken farms and slaughterhouses is a hazard to the consumers because it is transmitted along the whole production chain up to the final product ( Kim et al, 2019 ; Ramires et al, 2020 ). While the literature on broiler chicken is extensive, studies on the epidemiology of Campylobacter species from layer farms are limited ( Kassem et al, 2016 ).…”

“…Campylobacter species also possess other genes associated with adhesion ( cad F and pld A), invasion ( cia B), thermo-tolerance ( dna J) ( Pillay et al, 2020 ), and stress response ( csr A) ( Fields and Thompson, 2008 ). Studies have shown that Campylobacter strain mutants for cad F and cia B exhibited a reduced attachment and invasion of INT 407 cell line along with a decline of survival potential ( Kreling et al, 2020 ; Ramires et al, 2020 ).…”

Genomic Characterization of Fluoroquinolone-Resistant Thermophilic Campylobacter Strains Isolated from Layer Chicken Feces in Gangneung, South Korea by Whole-Genome Sequencing

“…Several studies have confirmed the roles of some of the virulence genes by observing the limited capacities of mutants to attach to, colonize, and invade eukaryotic cells [15,16]. Mutant strains lacking flaA and flaB were unable to complete the colonization process in chickens [13,17]. Also, cadF and ciaB mutant strains showed a reduced ability to adhere to and invade cell lines [17].…”