title: In vivo transmission of a plasmid coharbouring bla and qnrB genes between Escherichia coli and Serratia marcescens.
abstract: We report a Serratia marcescens and an Escherichia coli isolate simultaneously detected in the same patient. Both isolates showed susceptibility patterns suggestive of harbouring a plasmid-mediated AmpC beta-lactamase (pACBL) and a plasmid-encoded quinolone resistance (PMQR). PCR-based replicon, MOB typing, plasmid profile and Southern hybridization analyses revealed that both isolates coharboured bla(DHA-1) and qnrB genes on the same IncL/M-MOB(P13) plasmid approximately 70 kb in size. Together with the fact that both plasmids were conjugative in the laboratory, these results strongly suggest that a horizontal transfer event could take place in vivo. This is the first report of an isolate of S. marcescens harbouring a pACBL. The only phenotypic method that suggests the presence of a pACBL in an isolate harbouring an inducible chromosomal AmpC enzyme is the observation of scattered colonies near the edge of the inhibition zones of some beta-lactams. The presence of both resistance genes on the same plasmid and the reported increase in PMQR could perhaps explain the widespread distribution of bla(DHA-1) genes.
authors.affiliation: Servei de Microbiologia, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
authors.forename: Caterina
authors.initials: C
authors.lastname: Mata
authors.forename: Elisenda
authors.initials: E
authors.lastname: Miró
authors.forename: Beatriz
authors.initials: B
authors.lastname: Mirelis
authors.forename: Maria Pilar
authors.initials: MP
authors.lastname: Garcillán-Barcia
authors.forename: Fernando
authors.initials: F
authors.lastname: de la Cruz
authors.forename: Pere
authors.initials: P
authors.lastname: Coll
authors.forename: Ferran
authors.initials: F
authors.lastname: Navarro
mesh_terms: D000368:Aged; D015139:Blotting, Southern; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D010957:Plasmids; D016133:Polymerase Chain Reaction; D015363:Quinolones / Q000494:pharmacology; D016868:Serratia Infections / Q000382:microbiology; D012706:Serratia marcescens / Q000235:genetics* / Q000302:isolation & purification; D001618:beta-Lactamases / Q000235:genetics; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D004269:DNA, Bacterial; D015363:Quinolones; D047090:beta-Lactams; D001618:beta-Lactamases