Molecular identification of aminoglycoside-modifying enzymes in clinical isolates of Escherichia coli resistant to amoxicillin/clavulanic acid isolated in Spain
Fernández-Martínez, Marta (Hospital Universitario Marqués de Valdecilla (Santander, Cantabria))
Miró, Elisenda (Institut d'Investigació Biomèdica Sant Pau)
Ortega, Adriana (Centro Nacional de Microbiología (Espanya))
Bou, German (Complejo Hospitalario Universitario de A Coruña)
González, Juan José (Hospital Universitari Vall d'Hebron)
Oliver, Antonio (Hospital Universitari Son Espases (Palma de Mallorca, Balears))
Pascual Hernández, Álvaro (Hospital Universitario Virgen Macarena (Sevilla, Andalusia))
Cercenado, Emilia (Hospital General Universitario Gregorio Marañón)
Oteo-Iglesias, Jesús (Centro de Investigación Biomédica en Red de Enfermedades Respiratorias)
Martínez-Martínez, Luis (Hospital Universitario Marqués de Valdecilla (Santander, Cantabria))
Navarro Risueño, Ferran (Universitat Autònoma de Barcelona. Departament de Genètica i de Microbiologia)

Data:	2015
Resum:	The activity of eight aminoglycosides (amikacin, apramycin, arbekacin, gentamicin, kanamycin, neomycin, netilmicin and tobramycin) against a collection of 257 amoxicillin/clavulanic acid (AMC)-resistant Escherichia coli isolates was determined by microdilution. Aminoglycoside resistance rates, the prevalence of aminoglycoside-modifying enzyme (AME) genes, the relationship between AME gene detection and resistance phenotype to aminoglycosides, and the association of AME genes with mechanisms of AMC resistance in E. coli isolates in Spain were investigated. Aminoglycoside-resistant isolates were screened for the presence of genes encoding common AMEs [aac(3)-Ia, aac(3)-IIa, aac(3)-IVa, aac(6')-Ib, ant(2')-Ia, ant(4')-IIa and aph(3')-Ia] or 16S rRNA methylases (armA, rmtB, rmtC and npmA). In total, 105 isolates (40. 9%) were resistant to at least one of the aminoglycosides tested. Amikacin, apramycin and arbekacin showed better activity,with MIC90 values of 2 mg/L (arbekacin) and 8 mg/L (amikacin and apramycin). Kanamycin presented the highest MIC90 (128 mg/L). The most common AME gene was aac(6')-Ib (36 strains; 34. 3%), followed by aph(3')-Ia (31 strains; 29. 5%), ant(2')-Ia (29 strains; 27. 6%) and aac(3)-IIa (23 strains; 21. 9%). aac(3)-Ia, aac(3)-IVa, ant(4')-IIa and the four methylases were not detected. The ant(2')-Ia gene was usually associated with OXA-1 [21/30; 70%], whilst 23/25 (92%) strains producing CTX-M-15 had the aac(6')-Ib gene. The most prevalent AME gene was aac(6')-Ib (18/41; 44%) in nosocomial isolates, whilst ant(2')-Ia and aph(3')-Ia genes (20/64; 31%) were more frequent in strains of community origin. In 64. 6% isolates the phenotypic profile correlated with the presence of commonly encountered AMEs.
Ajuts:	Instituto de Salud Carlos III RD12/0015 Ministerio de Economía y Competitividad PI12/00552
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Aminoglycoside ; Aminoglycoside-modifying enzyme ; Amoxicillin/clavulanic acid ; Escherichia coli ; Resistance
Publicat a:	International Journal of Antimicrobial Agents, Vol. 46, Issue 2 (August 2015) , p. 157-163, ISSN 1872-7913

DOI: 10.1016/j.ijantimicag.2015.03.008

Postprint 56 p, 850.1 KB

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