Virulence and Genomic Feature of Multidrug Resistant Campylobacter jejuni Isolated from Broiler Chicken

Abstract

The aim of this study was to reveal the molecular mechanism involved in multidrug resistance and virulence of Campylobacter jejuni isolated from broiler chickens. The virulence of six multidrug resistant C. jejuni was determined by in vitro and in vivo methods. The de novo whole genome sequencing technology and molecular biology methods were used to analyze the genomic features associated with the multidrug resistance and virulence of a selected isolate (C. jejuni 1655). The comparative genomic analyses revealed a large number of single nucleotide polymorphisms, deletions, rearrangements, and inversions in C. jejuni 1655 compared to reference C. jejuni genomes. The co-emergence of Thr-86-Ile mutation in gyrA gene, A2075G mutation in 23S rRNA gene, tetO, aphA and aadE genes and pTet plasmid in C. jejuni 1655 contributed its multidrug resistance to fluoroquinolones, macrolides, tetracycline, and aminoglycosides. The combination of multiple virulence genes may work together to confer the relative higher virulence in C. jejuni 1655. The co-existence of mobile gene elements (e.g., pTet) and CRISPR-Cas system in C. jejuni 1655 may play an important role in the gene transfer and immune defense. The present study provides basic information of phenotypic and genomic features of C. jejuni 1655, a strain recently isolated from a chicken displaying multidrug resistance and relatively high level of virulence.

Genetic characterisation of a subset of Campylobacter jejuni isolates from clinical and poultry sources in Ireland

“…This transposon was previously identified in Campylobacter spp . in association with aminoglycoside resistance [ 65 , 66 ]. In this study, its prevalence in clinical isolates could indicate possible public health significance.…”

The Involvement of the Cas9 Gene in Virulence of Campylobacter jejuni

“…These three fragments were ligated together by adopting the method of overlapping PCR. This overlapping PCR product was then ligated to the pGem-Teasy vector (Promega; Hao et al, 2016 ). The resulting constructs were sequenced and electroporated into the C. jejuni NCTC11168 strain and recombinants were selected on blood agar plates containing 5% sheep blood (Becton Dickinson) and 50 μg/mL kanamycin (Sigma-Aldrich).…”

“…The adhesion and invasion of C. jejuni and Δ cas9 mutant strains were determined as previously described for C. jejuni and other bacteria (Hao et al, 2016 ). Briefly, 5.0 × 10 7 CFU/mL of the C. jejuni and Δ cas9 mutant was used to inoculate the monolayers of macrophages RAW264.7 at multiplicity of infection (MOI) of 100.…”

“…A Trypan Blue Dye uptake (A540 value) was used to determine the cell death and after that a staining technique known as “Giemsa staining” was used to correlate with normal cell morphology. The index of cytotoxin effect was calculated by the formula (Hao et al, 2016 ) 100 × {1–[A540 (test) A540 (positive)] ÷[A540(negative)–A540 (positive)]}.…”

A Historical Review on Antibiotic Resistance of Foodborne Campylobacter

“…Numerous studies point to multimodal resistance becoming an important component of Campylobacter drug resistance. Hao et al (2016) found that C. jejuni 1655 had several mutations at different target sties for antibiotics, including Thr-86-Ile mutation in gyrA and the A2075G mutation in 23S rRNA , tetO , aphA , and aadE genes. Additionally, C. jejuni 1655 carried a pTet plasmid.…”