Isolation and characterization of thermophilic Campylobacter species from geese raised in Kars region (Turkey) using cultural, molecular and mass spectrometry methods

Antibiotic resistance in Campylobacter jejuni and Campylobacter coli: significant contribution of an RND type efflux pump in erythromycin resistance

In this study, we aimed to determine the antibiotic resistance status of Campylobacter spp. isolated from human infections in our region, including the role of mechanisms involved in erythromycin resistance. Standard methods were used for the isolation, identification and antibiotic susceptibility testing of Campylobacter spp. isolates. Erythromycin-resistant mutants were selected from erythromycin-susceptible clinical isolates, and the erythromycin resistance mechanisms were investigated phenotypically by determining the erythromycin MICs of isolates in the presence and absence of the resistance nodulation cell division (RND) type efflux pump inhibitor, phenylalanine-arginine β-naphthylamide dihydrochloride (PAβN), and genotypically by determining ribosomal and cmeABC alterations using PCR and DNA sequence analysis. Campylobacter spp., including 184 C. jejuni and 20 C. coli in a two-year period, were the most frequently isolated gastrointestinal bacterial pathogens in our region. However, in both C. jejuni and C. coli, resistance to tetracycline and ciprofloxacin were found to be high, erythromycin resistance was especially high (20%) in C. coli. With a ribosomal alteration, A2075G, which was found to be associated with high-level erythromycin resistance in clinical isolates, PAβN significantly reduced the erythromycin MICs in both clinical isolates and mutants. An important finding of this study, while considering cmeABC operon, is the explanation of why erythromycin resistance is more common among C. coli than C. jejuni, bearing in mind the specific deletions and alterations in the intergenic region of the operon in all erythromycin-resistant C. coli isolates. Ultimately, these findings revealed the significant role of RND-type efflux activity in increased erythromycin MICs of the isolates.

Prevalence and antimicrobial resistance of Campylobacter species in shelter-housed healthy and diarrheic cats and dogs in Turkey

BACKGROUND

Campylobacter spp. are among the leading foodborne bacterial pathogens. Pet animals may be an important reservoir for human infection.

OBJECTIVES

To determine the prevalence and antimicrobial resistance profiles and mechanisms of Campylobacter isolates recovered from shelter-housed healthy and diarrheic cats and dogs in Erzurum province in Turkey.

METHODS

A total of 250 rectal swabs (from 124 cats and 126 dogs) collected between 2020 and 2021 were included in this study. The samples were cultured using a Campylobacter-selective agar medium. A single suspect colony from each plate was purified and species identification was performed by PCR. Minimum inhibitory concentration (MIC) values were determined against eight antibiotics. Specific antimicrobial resistance genes (tetO and aphA-3) and mutations (in gyrA) were screened by PCR and/or sequencing.

RESULTS

A total of 26 (10.4%) isolates (25 Campylobacter jejuni and 1 Campylobacter coli) were obtained from the dogs; no Campylobacter was isolated from the cats. Of the C. jejuni isolates, 19.2% were resistant to nalidixic acid, 7.7% to ciprofloxacin and 3.8% to tetracycline and gentamicin per the CLSI interpretative criteria. The C. coli isolate was susceptible to all of the tested antibiotics. Thr-86-Ile mutation was the most common change detected in the gyrA gene in the quinolone-resistant isolates.

CONCLUSION

While geographic and population differences exist, Campylobacter carriage and associated antibiotic resistance in dogs is common, emphasising the need for continuous surveillance in this species, particularly given its zoonotic potential.