Effect of Macrolide Usage on Emergence of Erythromycin-Resistant Campylobacter Isolates in Chickens

Abstract

In this work we conducted both in vitro and in vivo experiments to examine the development and mechanisms of erythromycin (Ery) resistance in Campylobacter jejuni and Campylobacter coli. In vitro plating revealed that both Campylobacter species had similar but low spontaneous mutation frequencies (3 ؋ 10 ؊9 to <5.41 ؋ 10 ؊10 ) for Ery resistance. Chickens infected with C. jejuni or C. coli were subjected to single or multiple treatments with medicated water containing tylosin (0.53 g/liter), which transiently reduced the level of Campylobacter colonization but did not select for Ery-resistant (Ery r ) mutants in the treated birds. However, when tylosin was given to the chickens in feed at a growth-promoting dose (0.05 g/kg feed), Ery r mutants emerged in the birds after prolonged exposure to the antibiotic. The vast majority of the in vitro-and in vivo-selected Campylobacter mutants with Ery MICs of 8 to 256 g/ml lacked the known resistance-associated mutations in the 23S rRNA gene, while the highly resistant mutants (Ery MIC > 512 g/ml) had the A2074G mutation in the 23S rRNA gene. Inactivation of CmeABC, a multidrug efflux pump, dramatically reduced the Ery MIC in all of the examined mutants regardless of the presence of the A2074G mutation. Together, these results reveal distinct features associated with Ery resistance development in Campylobacter, demonstrate the significant role of CmeABC in Ery resistance, and suggest that long-term use of a macrolide as a growth promoter selects for the emergence of Ery r Campylobacter in animal reservoirs.

The Challenge of Efflux-Mediated Antibiotic Resistance in Gram-Negative Bacteria

“…Macrolides and fluoroquinolones are the drugs of choice to treat human campylobacteriosis. The exposure of chickens to either a fluoroquinolone (enrofloxacin) in drinking water or a macrolide (tylosin) in animal feed readily resulted in the isolation of CmeABC-overproducing mutants with an MDR phenotype (656,667). In vitro stepwise exposures of C. jejuni to escalating levels of erythromycin or tylosin have generated a variety of macrolide-resistant mutants (668).…”

Mutational and Transcriptomic Changes Involved in the Development of Macrolide Resistance in Campylobacter jejuni

“…Selection of mutations in the 23S rRNA gene seems to require prolonged exposure to macrolide antibiotics, suggesting that other mutations or changes in Campylobacter may be required prior to the occurrence of the 23S rRNA mutations (2,10). Active efflux via the CmeABC multidrug efflux pump is another mechanism that confers resistance to macrolides on Campylobacter (10,12,13). By inactivation of the CmeABC efflux pump in resistant Campylobacter strains, previous studies revealed that CmeABC functions synergistically with the mutations in ribosomal proteins L4 (G74D) and L22 (insertions at position 86 or 98) or the 23S rRNA gene (A2075G) to confer macrolide resistance (10,11,(13)(14)(15).…”

“…Mutations in the L4 and L22 proteins appear to mediate low (MIC, 8 to 16 g/ml)-to-intermediate (MIC, 16 to 128 g/ml) levels of resistance to Ery, while mutations in the 23S rRNA gene are associated with high-level (MIC, Ն256 g/ml) Ery resistance (5,10,11). Selection of mutations in the 23S rRNA gene seems to require prolonged exposure to macrolide antibiotics, suggesting that other mutations or changes in Campylobacter may be required prior to the occurrence of the 23S rRNA mutations (2,10). Active efflux via the CmeABC multidrug efflux pump is another mechanism that confers resistance to macrolides on Campylobacter (10,12,13).…”

Influência da vida séssil e planctônica no perfil de resistência antimicrobiana de Campylobacter jejuni isoladas de carcaças de frangos comercializadas no Brasil

“…Os dois primeiros mecanismos atuam sinergicamente para conferir resistência de alto nívelaos macrolídeos (CAGLIERO et al, 2006;BRASIL, 2007;LIN et al, 2007;LOGUE et al, 2010).…”

“…A bomba de efluxo multidrogas CmeABC também contribui para a resistência aos macrolídeos (LIN et al, 2007;ZEITOUNI et al, 2012) e funciona de forma sinérgica com as mutações do rRNA 23S para promover resistência de alto nível (CAGLIERO et al, 2006;CALDWELL et al, 2008). A resistência de alto nível a eritromicina pode estar relacionada à presença do gene erm, o qual pode estar associado com ilhas de resistência multidrogas cromossômicas ou de plasmídeos transferíveis (WANG et al, 2015;EFSA, 2017 Os mecanismos atribuídos à resistência à tetraciclina estão relacionados ao efluxo, por meio da diminuição da acumulação da droga no interior da célula;…”