Antimicrobial resistance genotypes and phenotypes of Campylobacter jejuni isolated in Italy from humans, birds from wild and urban habitats, and poultry

Abstract

Campylobacter jejuni, a common foodborne zoonotic pathogen, causes gastroenteritis worldwide and is increasingly resistant to antibiotics. We aimed to investigate the antimicrobial resistance (AMR) genotypes of C. jejuni isolated from humans, poultry and birds from wild and urban Italian habitats to identify correlations between phenotypic and genotypic AMR in the isolates. Altogether, 644 C. jejuni isolates from humans (51), poultry (526) and wild- and urban-habitat birds (67) were analysed. The resistance phenotypes of the isolates were determined using the microdilution method with EUCAST breakpoints, and AMR-associated genes and single nucleotide polymorphisms were obtained from a publicly available database. Antimicrobial susceptibility testing showed that C. jejuni isolates from poultry and humans were highly resistant to ciprofloxacin (85.55% and 76.47%, respectively), nalidixic acid (75.48% and 74.51%, respectively) and tetracycline (67.87% and 49.02%, respectively). Fewer isolates from the wild- and urban-habitat birds were resistant to tetracycline (19.40%), fluoroquinolones (13.43%), and quinolone and streptomycin (10.45%). We retrieved seven AMR genes (tet (O), cmeA, cmeB, cmeC, cmeR, blaOXA-61 and blaOXA-184) and gyrA-associated point mutations. Two major B-lactam genes called blaOXA-61 and blaOXA-184 were prevalent at 62.93% and 82.08% in the poultry and the other bird groups, respectively. Strong correlations between genotypic and phenotypic resistance were found for fluoroquinolones and tetracycline. Compared with the farmed chickens, the incidence of AMR in the C. jejuni isolates from the other bird groups was low, confirming that the food-production birds are much more exposed to antimicrobials. The improper and overuse of antibiotics in the human population and in animal husbandry has resulted in an increase in antibiotic-resistant infections, particularly fluoroquinolone resistant ones. Better understanding of the AMR mechanisms in C. jejuni is necessary to develop new strategies for improving AMR programs and provide the most appropriate therapies to human and veterinary populations.

Risk of multi-drug resistant Campylobacter spp. and residual antimicrobials at poultry farms and live bird markets in Bangladesh

“…This may explain the dissimilarity in major resistance patterns among Campylobacter strains reported in different studies. For example, in contrast to the results obtained in this study a low frequency of erythromycin resistant strains but high frequency of resistance to ciprofloxacin, nalidixic acid and tetracycline were reported for Campylobacter isolates in Italy and Brazil [10,36]. The higher frequency of resistant strains in C. jejuni than C. coli, particularly when considering resistance to multiple antimicrobials, namely, amoxicillin, tetracycline, erythromycin and ciprofloxacin ( Table 2, and also see Additional file 4), could be related to the overwhelming natural predominance of the former species.…”

Risk of multi-drug resistant Campylobacter spp. and residual antimicrobials at poultry farms and live bird markets in Bangladesh

“…This may explain the dissimilarity in major resistance patterns among Campylobacter strains reported in different studies. For example, in contrast to the results obtained in this study a low frequency of erythromycin resistant strains but high frequency of resistance to ciprofloxacin, nalidixic acid and tetracycline were reported for Campylobacter isolates in Italy and Brazil [10,33]. The higher frequency of resistant strains in C. jejuni than C. coli, particularly when considering resistance to multiple antimicrobials, namely, amoxicillin, tetracycline, erythromycin and ciprofloxacin ( Table 2, and also see Additional File 4), could be related to the overwhelming natural predominance of the former species.…”

“…The gastrointestinal tract of poultry, wild birds, and livestock animals constitute the primary reservoir of Campylobacter spp. Campylobacter jejuni and Campylobacter coli are the predominant species of Campylobacter in poultry [5,10]. These bacteria are commonly known to be harmless gut flora of chicken, which remain healthy but serve as carriers for human infection.…”

Occurrence of tet(O/M/O) Mosaic Gene in Tetracycline-Resistant Campylobacter

“…isolated from humans. Elhadidy et al [30], found 49.7% resistance to tetracycline, much in accordance with the level of resistance found by Marotta et al [31], with 49.0% resistant isolates, even though this last study used the epidemiological cut-off values (ECOFFs) defined by EUCAST [32]. Considering the same resistance definition, the study carried out in Spain by Ocejo et al [33] showed that the level of resistance in Campylobacter spp., isolated from animals, was 76.5%.…”