Resistome Analysis of Campylobacter jejuni Strains Isolated from Human Stool and Primary Sterile Samples in Croatia

Abstract

Campylobacteriosis represents a global health challenge due to continuously increasing trends of antimicrobial resistance in Campylobacter jejuni. C. jejuni can sometimes cause life-threatening and severe systematic infections (bacteremia, meningitis, and other extraintestinal infections) with very few antibiotics left as treatment options. Bearing in mind that C. jejuni is the predominant species in humans, in this paper, we present a study of the C. jejuni differences in antimicrobial resistance and genotype distribution between strains isolated from stool and primary sterile sites. We compared the genomic data obtained through whole genome sequencing (WGS) and phenotypic susceptibility data of C. jejuni strains. Once antimicrobial susceptibility testing of C. jejuni strains was carried out by the broth microdilution method for six of interest, results were compared to the identified genotypic determinants derived from WGS. The high rate of resistance to fluoroquinolones presented in this study is in accordance with national surveillance data. The proportion of strains with acquired resistance was 71% for ciprofloxacin and 20% for tetracycline. When invasive isolates were analysed separately, 40% exhibited MIC values of ciprofloxacin higher than the ECOFFs, suggesting a lower flouroquinolone resistance rate in invasive isolates. All isolates demonstrated wilde-type phenotype for chloramphenicol, erythromycin, gentamicin, and ertapenem. A special focus and review in this study was performed on a group of C.jejuni strains found in primary sterile samples. Apart from demonstrating a lower resistance rate, these isolates seem genetically more uniform, showing epidemiologically more homogenous patterns, which cluster to several clonal complexes, with CC49 being the most represented clonal complex.

Genetic characteristics, antimicrobial susceptibility, and virulence genes distribution of Campylobacter isolated from local dual-purpose chickens in central China

“…( Iovine, 2013 ). The determinants of drug resistance do not always confer resistance phenotypes, and single resistance determinant may correlate weakly with certain antibiotics ( Šoprek et al, 2022 ). In this study, we found that the overall correlation between the 16 antibiotic resistance determinants detected with ResFinder v.4.1 and phenotypic resistance was not strong, and that there were huge differences between the different antibiotics.…”

First Report of Campylobacter jejuni Strains Belonging to ST-21 Clonal Complex Isolated from Human, Poultry and Wild Birds in Croatia: Antimicrobial Resistance and Genetic Distance

“…The majority of the strains were selected from the collection of C. jejuni at the Croatian Veterinary Institute, collected within other studies on Campylobacter spp. during a period of 2021–2022 [ 10 ].…”

“…The human strains were collected in the University Hospital for Infectious Diseases (samples ZG01, ZG02, ZG03, ZG06, ZG07, ZGI07, ZG12) and included strains from stool and blood samples of patients with diarrhea also during 2021 and 2022. These isolates were previously analyzed for the antimicrobial resistance [ 10 ] and added to other ST-21 isolates.…”

“…The aim of the study was to investigate all ST-21 CC strains of C. jejuni obtained from several niches, including human, broiler, and wild birds, identified in our prior studies [ 10 ], as we found this ST-21 CC emerging in wild birds. As it was observed that ST-21 CC carries high resistance to ciprofloxacin and tetracycline, it poses a danger for further spread in the ecosystem.…”