Evidence for convergent evolution of CTX-M-14 ESBL in Escherichia coli and its prevalence.
A total of 2440 Escherichia coli strains isolated in 2003 at the Hospital de la Santa Creu i Sant Pau were evaluated for the presence of extended-spectrum beta-lactamases. Two different nucleotide sequences that encode the same beta-lactamase, CTX-M-14, were detected when the bla(CTX-M-14)-genes of 35 E. coli isolates were analysed. Thirty-two of the 35 had the previously described sequence of the bla(CTX-M-14) (AF252622), named bla(CTX-M-14a), and the remaining three isolates showed a nucleotide sequence identical to that of the bla(CTX-M-9) gene except for one nucleotide, named bla(CTX-M-14b). Characterisation of the regions surrounding the bla(CTX-M-14a) showed the ISEcp1 and the IS903 upstream and downstream, respectively, of the bla gene, whereas the regions surrounding the bla(CTX-M-14b) contained the genetic environment described for the bla(CTX-M-9) gene, the In60. Characterisation by hybridisation showed that the bla(CTX-M-14a) was present in IncK plasmids, whereas the bla(CTX-M-14b) was found in the HI2 Inc group. The CTX-M-14 ESBL in E. coli isolates is the result of the convergence of two different genes.
Navarro
Ferran
F
Servei de Microbiologia de l'Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. fnavarror@santpau.es
Mesa
Rául-Jesús
RJ
Miró
Elisenda
E
Gómez
Laura
L
Mirelis
Beatriz
B
Coll
Pere
P
D001483:Base Sequence; D005075:Biological Evolution; D002876:Chromosomes, Bacterial / Q000235:genetics; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; 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; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D001618:beta-Lactamases / Q000235:genetics*
D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C412613:CTX-M-9 protein, E coli; C456080:beta-lactamase CTX-M-14; D001618:beta-Lactamases