Azithromycin resistance levels and mechanisms in Escherichia coli

Gomes, Claudia; Mateu, Judit; Ochoa Woodell, Theresa Jean; Ruiz, Joaquim; Ruiz-Roldan, Lidia

dc.contributor.author	Gomes, Claudia
dc.contributor.author	Ruiz-Roldan, Lidia
dc.contributor.author	Mateu, Judit
dc.contributor.author	Ochoa Woodell, Theresa Jean
dc.contributor.author	Ruiz, Joaquim
dc.date.accessioned	2019-07-04T16:59:21Z
dc.date.available	2019-07-04T16:59:21Z
dc.date.issued	2019
dc.identifier.uri	https://hdl.handle.net/20.500.12866/6730
dc.description.abstract	Despite azithromycin being used in some countries to treat infections caused by Gram-negative pathogens, no resistance breakpoint for Escherichia coli exists. The aim of this study was to analyse the levels and mechanisms of azithromycin resistance in E. coli. The presence of chromosomal (rplD, rplV and 23S rRNA) mutations, 10 macrolide resistance genes (MRGs) and efflux pump overexpression was determined in 343 E. coli isolates. Overall, 89 (25.9%) isolates had MICs ≥ 32 mg/L to azithromycin, decreasing to 42 (12.2%) when assayed in the presence of Phe-Arg-β-Napthylamide, with 35 of these 42 possessing at least one MRG. Efflux pumps played a role in azithromycin resistance affecting the Minimal Inhibitory Concentration (MIC) levels of 91.2% isolates whereas chromosomal alterations seem to have a minimal role. At least one MRG was found in 22.7% of the isolates with mph(A) being the most commonly found gene. The mph(A) gene plays the main role in the development of azithromycin resistance and 93% of the mph(A)-carrying isolates showed a MIC of 32 mg/L. In the absence of a specific resistance breakpoint our results suggest a MIC of 32 mg/L to be considered in order to detect isolates carrying mechanisms able to confer azithromycin resistance.	en_US
dc.language.iso	eng
dc.publisher	Springer Nature
dc.relation.ispartofseries	Scientific Reports
dc.rights	info:eu-repo/semantics/restrictedAccess
dc.rights.uri	https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es
dc.subject	Antimicrobial resistance	en_US
dc.subject	Bacterial infection	en_US
dc.title	Azithromycin resistance levels and mechanisms in Escherichia coli	en_US
dc.type	info:eu-repo/semantics/article
dc.identifier.doi	https://doi.org/10.1038/s41598-019-42423-3
dc.subject.ocde	https://purl.org/pe-repo/ocde/ford#3.01.05
dc.subject.ocde	https://purl.org/pe-repo/ocde/ford#1.06.01
dc.relation.issn	2045-2322