Macrolide resistance mechanisms and virulence factors in erythromycin-resistant <i>Campylobacter</i> species isolated from chicken and swine feces and carcasses

Abstract

Resistance to antimicrobials was measured in 73 isolates of Campylobacter jejuni (C. jejuni) and 121 isolates of Campylobacter coli (C. coli) from chicken and swine feces and carcasses in Korea. Both bacterial species showed the highest resistance to (fluoro) quinolones (ciprofloxacin and nalidixic acid) out of the nine antimicrobials tested. Erythromycin resistance was much higher in C. coli (19.0%, 23/121) than in C. jejuni (6.8%, 5/73). The mutation in the 23S rRNA gene was primarily responsible for macrolide resistance in Campylobacter isolates. Several amino acid substitutions in the L4 and L22 ribosomal proteins may play a role in the mechanism of resistance, but the role requires further evaluation. A total of eight virulence genes were detected in 28 erythromycin-resistant Campylobacter isolates. All C. jejuni isolates carried more than four such genes, while C. coli isolates carried fewer than three such genes. The high rate of resistance highlights the need to employ more prudent use of critically important antimicrobials, such as fluoroquinolones and macrolides, in swine and poultry production, and to more carefully monitor antimicrobial resistance in Campylobacter isolates in food animals.

Molecular Basis of Macrolide Resistance inCampylobacterStrains Isolated from Poultry in South Korea

“…The substitution A2075G was the most prevalent genetic mutation conferring high macrolide resistance in the field, suggesting A2075G may provide specific biological or survival advantages compared to A2074G and A2074C [ 3 , 20 – 22 ]. Our results were also consistent with those of previous studies in Korea that suggested that the A2075G mutation in the 23S rRNA gene appeared to be the main contributor to high macrolide resistance [ 23 , 24 ].…”

“…This suggests that these substitutions are unlikely to contribute directly to macrolide resistance [ 27 ]. Other substitutions such as V80I, T177S, and M192I were also identified in erythromycin-susceptible and -resistant isolates previously [ 23 , 27 ]. In L22, substitutions including I65V, A74G, A103V, and S109A were identified in erythromycin-susceptible and -resistant isolates previously [ 27 , 28 ].…”

Campylobacteriosis Agents in Meat Carcasses Collected from Two District Municipalities in the Eastern Cape Province, South Africa

“…In this study, the cdtB gene was observed to be widespread among the Campylobacter species, with C. coli strains revealed to have a higher prevalence rate of cdtB than C. jejuni and C. fetus (Table 3), and our results are not in agreement with the reports of Wieczorek et al [82] and Reddy and Zishiri [83], which reported a higher prevalence rate of the cdtB gene in C. jejuni than in the C. coli strain. Multiple virulence genes were also detected in both C. coli and C. jejuni with C. coli observed to harbour more virulence genes than C. jejuni, and these results are in contrast with the reports of Lim et al [84] and Zhang et al [85]. Campylobacter isolates have also been reported by Han et al [86] to co-harbour more than three virulence genes, and our findings corroborate this report.…”

Increasing prevalence of a fluoroquinolone resistance mutation amongst Campylobacter jejuni isolates from four human infectious intestinal disease studies in the United Kingdom

“…In humans, the antibiotics most commonly used to treat Campylobacter infections are macrolides such as erythromycin. Mutations in ribosomal proteins L4 and L22 have been associated with resistance to erythromycin in Campylobacter [37]. We identified mutations in the genes encoding these proteins (rplD and rplV) and compared prevalence between the four groups.…”