Antimicrobial resistance profiles, virulence genes, and genetic diversity of thermophilic campylobacter species isolated from a layer poultry farm in Korea
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
Frontiers in Microbiology
Abstract
Thermophilic Campylobacter species are among the major etiologies of bacterial
enteritis globally. This study aimed at assessing the antimicrobial resistance (AMR)
profiles, virulence genes, and genetic diversity of thermophilic Campylobacter species
isolated from a layer poultry farm in South Korea. One hundred fifty-three chicken
feces were collected from two layer poultry farms in Gangneung, South Korea.
The Campylobacter species were isolated by cultural techniques, while PCR and
sequencing were used for species confirmation. Antimicrobial susceptibility testing for
six antimicrobials [ciprofloxacin (CIP), nalidixic acid (NAL), sitafloxacin (SIT), erythromycin
(ERY), tetracycline (TET), and gentamicin (GEN)] was carried out by broth microdilution.
Three AMR and nine virulence genes were screened by PCR. Genotyping was
performed by flaA-restriction fragment length polymorphism (RFLP) and multilocus
sequence typing (MLST). Of the 153 samples, Campylobacter spp. were detected
in 55 (35.9%), with Campylobacter jejuni and Campylobacter coli being 49 (89.1%)
and six (10.9%), respectively. High-level resistance was observed for CIP (100%), NAL
(100%), and TET (C. jejuni, 93.9%; C. coli: 83.3%). No resistance was observed for SIT.
The missense mutation (C257T) in gyrA gene was confirmed by sequencing, while the
tet(O) gene was similar to known sequences in GenBank. The rate of multidrug-resistant
(MDR) strains was 8.2%, and they all belonged to C. jejuni. All Campylobacter isolates
possessed five virulence genes (cdtB, cstII, flaA, cadF, and dnaJ), but none possessed
ggt, while the rates for other genes (csrA, ciaB, and pldA) ranged between 33.3 and
95.9%. The flaA-RFLP yielded 26 flaA types (C. jejuni: 21 and C. coli: five), while the
MLST showed 10 sequence types (STs) for C. jejuni and three STs for C. coli, with CC-607 (STs 3611) and CC-460 (ST-460) being predominant. Among the 10 STs of
C. jejuni, three were newly assigned. The findings of this study highlight the increased
resistance to quinolones and TET, the virulence potential, and the diverse genotypes
among Campylobacter strains isolated from the layer poultry farm.
Description
Journal article
Keywords
Campylobacter, Quinolones, Antimicrobial resistance, flaA RFLP, Multilocus sequence typing, Poultry, Korea
Citation
doi: 10.3389/fmicb.2021.622275