Characterization of a novel macrolide efflux gene, mef(B), found linked to sul3 in porcine Escherichia coli

Abstract

A new macrolide efflux protein, Mef(B), with 38% amino acid identity to Mef(A), has been characterized and represents the second member of the mef family of genes.

Macrolide resistance mechanisms inEnterobacteriaceae: Focus on azithromycin

“…Among these, the AcrAB-TolC like RND-type efflux pumps present in different members of the genus are probably the best characterized efflux pumps of Enterobacteriaceae. The effect of AcrAB-TolC on the extrusion of different macrolides has been shown by developing defective (Liu et al, 2009) Ery: erythromycin; Azm: azithromycin; Tel: telithromycin; Jos: josamycin; Clar: clarithomycin; ? : proposed association.…”

“…Liu et al (2009) reported the presence of functional non-conjugative mef(B) genes, but located in mobilizable plasmids in two different genetic structures in a total of three E. coli isolates. Additionally, another two different genetic structures have also been described in two other isolates carrying a 254 bp fragment of the mef(B) gene truncated by the presence of a IS26.…”

Effects of Chlorophyll-Derived Efflux Pump Inhibitor Pheophorbideaand Pyropheophorbideaon Growth and Macrolide Antibiotic Resistance of Indicator and Anaerobic Swine Manure Bacteria

“…The plasmidborne Msr(A) transporter, even though mainly responsible for erythromycin efflux in S. aureus [103], is not present in the strain used in our study, S. aureus ATCC 29213 [104]. Mef(A) is closely related to Mef(B), the erythromycin efflux pump in E. coli P475.10.99.C3 [67], and as pyp decreased the final MIC endpoint for induced cultures of this strain (Figures 3(b) and 3(d)), it can be concluded that Mef(A) is an additional candidate for inhibition by pyp in S. aureus.…”

“…It is estimated to be quantitatively the second most common in-feed antimicrobial in the U.S. swine production [5] and is also approved for cattle and poultry [59]. [65][66][67]. The strains are best characterized as possessing the following MDR and macrolide efflux pumps: NorA (S. aureus), EmeA (Ent.…”

“…The strains are best characterized as possessing the following MDR and macrolide efflux pumps: NorA (S. aureus), EmeA (Ent. faecalis), AcrAB-TolC (S. Typhimurium), and Mef(B) (E. coli) [27,67].…”