Genotyping, antibiotic resistance and prevalence of Arcobacter species in milk and dairy products

Abstract

Background Arcobacter spp. has been considered an emerging foodborne pathogen and a hazard to human health. The dairy chain has been isolated from different sources; nevertheless, data on Arcobacter occurrence in raw milk and dairy products in Iran are still scant. Objective The present study investigates the prevalence, antimicrobial susceptibility and the presence of virulence genes of Arcobacters species isolated from milk and dairy products. Methods Then, a total of 350 raw milk samples and 400 dairy product samples were collected from dairy supply centers in Isfahan, Iran. Presumptive Arcobacter strains were obtained by enriching samples in Oxoid Arcobacter enrichment broth (AEB) followed by the filtration of enrichment product through 0.45‐μm pore size membrane filters laid onto non‐selective blood at 30°C under microaerophilic conditions. Molecular identification of Arcobacter cryaerophilus and A. butzleri was performed by Polymerase chain reaction (PCR) amplification of the 16S rRNA gene, followed by sequencing. The disc diffusion method was used to determine the antimicrobial susceptibility of isolates. Targeted resistance and virulence genes were detected using multiplex PCR. Results The results show a low recovery rate of Arcobacter spp. in milk. Arcobacters were found in all types of milk, except raw camel milk, but were absent from all dairy products. Arcobacter butzleri was the predominant species in raw milk. Detection of virulence genes shows that all virulence genes targeted were found among A. butzleri, and six (cadF, cj1349, irgA, mviN, pldA, tlyA) were found among A. cryaerophilus. All A. butzleri strains and some A. cryaerophilus strains isolated from milk were resistant to amoxicillin‐clavulanic acid and tetracycline. All A. cryaerophilus isolates from milk were susceptible to gentamycin, streptomycin, erythromycin and ciprofloxacin. The distribution of resistance genes in Arcobacter strains in milk shows that all isolates carried tet(O) and blaOXA‐61 genes. Conclusions In conclusion, the results indicate a low recovery rate of Arcobacter spp. in milk and milk products. However, a significant number of Arcobacter strains with putative virulence genes may be potential pathogens for humans and an overall increase in Arcobacter resistance to first‐line antibiotics. These results highlight the need for regular surveillance of Arcobacter strains in milk and milk products in Iran.

Virulence genotype and phenotype of two clinical isolates of Arcobacter butzleri obtained from patients with different pathologies

“…Previous studies point to a 100% prevalence for all of them (Fanelli et al 2020 ; Müller et al 2020a , b ; Uljanovas et al 2023 ) except for tetO , which is less frequently detected. Although three of the most recent studies carried out with A. butzleri did not detect it in any of the strains tested (Jehanne et al 2022 ; Müller et al 2020b ; Uljanovas et al 2023 ), those conducted by Sciortino et al ( 2021 ) and Lameei et al ( 2022 ) detected it in all tetracycline resistant strains examined. Here, the presence of the tetO gene in both genomes is probably the reason for resistance to tetracycline, as this genotype–phenotype correlation has previously been reported (Lameei et al 2022 ; Sciortino et al 2021 ; Zambri et al 2019 ).…”

“…Although three of the most recent studies carried out with A. butzleri did not detect it in any of the strains tested (Jehanne et al 2022 ; Müller et al 2020b ; Uljanovas et al 2023 ), those conducted by Sciortino et al ( 2021 ) and Lameei et al ( 2022 ) detected it in all tetracycline resistant strains examined. Here, the presence of the tetO gene in both genomes is probably the reason for resistance to tetracycline, as this genotype–phenotype correlation has previously been reported (Lameei et al 2022 ; Sciortino et al 2021 ; Zambri et al 2019 ). However, HC-2 also contained tetA , which, as reported elsewhere (Sciortino et al 2021 ) could also contribute to tetracycline resistance in this strain.…”

The occurrence of some foodborne pathogens recovered from poultry meat in Shahrekord, Iran

“…Incubation was done for 48 h at 30°C. Acobacter butzleri was identified by biochemical tests [ 13 ].…”