Characterization of the highly variable region surrounding the bla(CTX-M-9) gene in non-related Escherichia coli from Barcelona.
OBJECTIVE
The dispersion of a clone, a plasmid or a mobile element carrying the bla(CTX-M-9) gene was evaluated in 30 Escherichia coli strains isolated in Barcelona between 1996 and 1999. The presence of the previously described orf513-bearing class 1 integron, In60, carrying the bla(CTX-M-9) gene, was also studied.


METHODS
The clonality was analysed by pulsed-field gel electrophoresis. Plasmid analysis was performed by S1 digestion and hybridization with the CTX-M-9 probe. PCR mapping using specific designed primers was used to study the presence of In60 and In60-like structures.


RESULTS
The clonality between the 30 strains was minor. The size of bla(CTX-M-9) carrying plasmids ranged between approximately 80 and 430 kb. One strain produced only a chromosome-encoded CTX-M-9 beta-lactamase. Thirty-six per cent of the strains showed differences with respect to the In60 structure due to an insertion or deletion events.


CONCLUSIONS
These findings suggest that the bla(CTX-M-9) gene may be carried by a mobile element that disperses it between plasmids. The fast dispersion of the CTX-M-9 enzyme could therefore be due to both diffusion of plasmids and mobile elements.
García
Aurora
A
Servei de Microbiologia, Hospital de la Santa Creu i Sant Pau, 08025 Barcelona, Spain.
Navarro
Ferran
F
Miró
Elisenda
E
Mirelis
Beatriz
B
Campoy
Susana
S
Coll
Pere
P
D001483:Base Sequence; D002876:Chromosomes, Bacterial / Q000235:genetics; D016172:DNA Fingerprinting; D004251:DNA Transposable Elements / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics*; D023061:Gene Order; D006801:Humans; D032023:Integrons / Q000235:genetics; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D013030:Spain; D001618:beta-Lactamases / Q000235:genetics*
D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C412613:CTX-M-9 protein, E coli; D001618:beta-Lactamases