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

Abstract

We investigated the molecular mechanisms underlying macrolide resistance in 38 strains of Campylobacter isolated from poultry. Twenty-seven strains were resistant to azithromycin and erythromycin, five showed intermediate azithromycin resistance and erythromycin susceptibility, and six showed azithromycin resistance and erythromycin susceptibility. Four Campylobacter jejuni and six Campylobacter coli strains had azithromycin MICs which were 8–16 and 2–8-fold greater than those of erythromycin, respectively. The A2075G mutation in the 23S rRNA gene was detected in 11 resistant strains with MICs ranging from 64 to ≥ 512 μg/mL. Mutations including V137A, V137S, and a six-amino acid insertion (114-VAKKAP-115) in ribosomal protein L22 were detected in the C. jejuni strains. Erythromycin ribosome methylase B-erm(B) was not detected in any strain. All strains except three showed increased susceptibility to erythromycin with twofold to 256-fold MIC change in the presence of phenylalanine arginine ß-naphthylamide (PAßN); the effects of PAßN on azithromycin MICs were limited in comparison to those on erythromycin MICs, and 13 strains showed no azithromycin MIC change in the presence of PAßN. Differences between azithromycin and erythromycin resistance and macrolide resistance phenotypes and genotypes were observed even in highly resistant strains. Further studies are required to better understand macrolide resistance in Campylobacter.

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

“…A103V mutations in L22 have been reported previously in erythromycin-resistant Campylobacter isolates, though the mutation can also occur in susceptible isolates [38,39]. Mutations in the 23S rRNA gene (position 2074 or 2075) have also been implicated in resistance to erythromycin [38]. In our collection, only one isolate (H083720456) harboured such a mutation (A2075G variant).…”

“…The only difference reaching statistical significance was an increase in prevalence of an A103V mutation in rplV (encoding L22), rising from 7.6% in IID1 to 19.6% in ENIGMA (p = 0.034). A103V mutations in L22 have been reported previously in erythromycin-resistant Campylobacter isolates, though the mutation can also occur in susceptible isolates [38,39]. Mutations in the 23S rRNA gene (position 2074 or 2075) have also been implicated in resistance to erythromycin [38].…”

Detección del gen ermB asociado a la resistencia a macrólidos en cepas de Campylobacter aisladas de pollos comercializados en Lima, Perú

“…La detección del gen ermB en 53% (62/117) de cepas fenotípicamente resistentes a macrólidos lo posiciona como el principal mecanismo de resistencia en cepas aisladas de mercados de Lima, Perú, con un nivel de detección superior a los hallados en otros países ( 12 ). En este estudio, se encontró una alta carga de cepas de C. coli resistentes a macrólidos.…”

“…Este gen fue reportado por primera vez en el año 2014 en una cepa de C. coli proveniente de un cerdo en China; luego fue detectado en cepas de Campylobacter aisladas de pollos y cerdos en España y Francia, respectivamente ( 11 ). La presencia del gen ermB en cepas de C. coli tendría su origen en bacterias grampositivas e incorporado a su genoma por transformación natural, lo que constituye un tipo de transmisión horizontal de genes ( 3 , 12 ).…”

“…Esta capacidad es de interés para la salud pública, debido a que C. jejuni es el responsable de más de 90% de casos de infecciones por Campylobacter en los que la azitromicina, antibiótico del grupo de los macrólidos, es la primera línea de tratamiento ( 2 ). Por otro lado, la presencia de este gen también presenta una asociación cada vez más frecuente con islas genómicas multidrogorresistentes, capaces de ser transferidas a diferentes bacterias con suma facilidad ( 6 , 12 ). El objetivo del presente estudio es detectar el gen ermB y su relación con la resistencia bacteriana a los macrólidos en las cepas de Campylobacter aisladas de piel de pollo de los principales mercados de Lima, Perú.…”