In vivo transmission of a plasmid coharbouring bla and qnrB genes between Escherichia coli and Serratia marcescens.
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.
Mata
Caterina
C
Servei de Microbiologia, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
Miró
Elisenda
E
Mirelis
Beatriz
B
Garcillán-Barcia
Maria Pilar
MP
de la Cruz
Fernando
F
Coll
Pere
P
Navarro
Ferran
F
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
D004269:DNA, Bacterial; D015363:Quinolones; D047090:beta-Lactams; D001618:beta-Lactamases