A novel macrolide esterase EstX that not included in CARD database.

[cc1000ml]

We find EstX is a macrolide esterase that could degrade veterinary (tylosin, tidipirosin, and tilmicosin) and human-use (leucomycin A5) antibiotics. Carrying this gene could also confer tylosin and tilmicosin resistance to E. coli. We hope you could include this protein into CARD database. The relevant information was listed below: genbank gene ID: PP210101.1, genbank protein ID: WVE62698.1 Publication is: Lin, J., Lv, H., Wang, T. et al. The global distribution of the macrolide esterase EstX from the alpha/beta hydrolase superfamily. Commun Biol 7, 781 (2024). https://doi.org/10.1038/s42003-024-06473-2

[TomJove]

This is very interesting, thank you for letting us know about it! Interestingly, EstX is encoded on so-called mobile (class 1) integrons very common in Gram neg bacteria but mostly absent or much rarer in Gram + bacteria. Indeed integrons Pc promoter ensuring integrons antibiotic resistance genes is most likely inefficient in Gram +. E.coli, a common integrons host, is naturally resistant to tylosin so the benefit of such genes would mostly be for Gram +. Nevertheless these bacteria have no integrons. Intruiging!

[cc1000ml]

Thanks for your comment~ We hope CARD could include this gene because it's appearence in different countries and different bacteria strains including Escherichia coli, Salmonella enterica, and Klebsiella pneumoniae.
As you said, EstX could confer tylosin resistance to E. coli while E. coli is naturally resistant to tylosin. It is strange, but could also be seen in other macrolide esterase. For example, EreA or EreB could also confer E. Coli with resistance to Erythromycin which is not so effective to E. coli.