title: Characterization of aminoglycoside-modifying enzymes in enterobacteriaceae clinical strains and characterization of the plasmids implicated in their diffusion.
abstract: A total of 788 clinical Enterobacteriaceae were collected to describe the aminoglycoside-modifying genes (AME genes) and to characterize the plasmids that carry these genes. Among the 788 strains collected, 330 (41.8%) were aminoglycoside-resistant: 264 Escherichia coli (80%), 33 Proteus mirabilis (10%), 10 Klebsiella pneumoniae (3%), six K. oxytoca (1.8%), five Enterobacter cloacae (1.5%), three Morganella morganii (0.9%), three Providencia stuartii (0.9%), two Salmonella enterica (0.6%), and one each Citrobacter freundii, C. koseri, Proteus vulgaris, and Shigella sonnei. The most affected aminoglycoside was streptomycin (92.7%), followed by kanamycin (26.3%), gentamicin (18%), tobramycin (16.9%), netilmicin (3.6%), and amikacin (1.5%). The AME genes found were aph(3″)-Ib (65.4%), ant(3″)-Ia (37.5%), aph(3')-Ia (13.9%), aac(3)-IIa (12.4%), aac(6')-Ib (4.2%), ant(2″)-Ia (3.6%), and aph(3')-IIa (1.2%). Thirty-four percent of the strains showed more than one enzyme. The most frequent association was ant(3″)-Ia plus aph(3″)-Ib (35 strains). From 66 selected AME genes, 24 were plasmid located: 12 aac(3)-IIa, six aph(3')-Ia, three ant(3″)-Ia, two ant(2″)-Ia, and one aac(6')-Ib. These genes were located in plasmids belonging to incompatibility groups F, FIA, FIB, or HI2. In conclusion, the AME genes involved in aminoglycoside-clinical resistance were aac(3)-IIa, aac(6')-Ib, and ant(2″)-Ia, genes that confer resistance to tobramycin, gentamicin, and amikacin.
authors.affiliation: Servei de Microbiologia, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
authors.forename: Elisenda
authors.initials: E
authors.lastname: Miró
authors.forename: Federico
authors.initials: F
authors.lastname: Grünbaum
authors.forename: Laura
authors.initials: L
authors.lastname: Gómez
authors.forename: Alba
authors.initials: A
authors.lastname: Rivera
authors.forename: Beatriz
authors.initials: B
authors.lastname: Mirelis
authors.forename: Pere
authors.initials: P
authors.lastname: Coll
authors.forename: Ferran
authors.initials: F
authors.lastname: Navarro
mesh_terms: D000617:Aminoglycosides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015373:Bacterial Typing Techniques; D024881:Drug Resistance, Bacterial / Q000187:drug effects / Q000235:genetics*; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000188:drug therapy / Q000382:microbiology; D006801:Humans; D009154:Mutation; D010957:Plasmids; D016133:Polymerase Chain Reaction
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins