Molecular epidemiology of Escherichia coli producing extended-spectrum {beta}-lactamases in Lugo (Spain): dissemination of clone O25b:H4-ST131 producing CTX-M-15.
OBJECTIVE
Having shown that the Xeral-Calde Hospital in Lugo (Spain) has been concerned by Escherichia coli clone O25:H4-ST131 producing CTX-M-15 (Nicolas-Chanoine et al. J Antimicrob Chemother 2008; 61: 273-81), the present study was carried out to evaluate the prevalence of this clone among the extended-spectrum beta-lactamase (ESBL)-producing E. coli isolates and also to molecularly characterize the E. coli isolates producing ESBL other than CTX-M-15.


METHODS
In the first part of this study, 105 ESBL-producing E. coli isolates (February 2006 to March 2007) were characterized with regard to ESBL enzymes, serotypes, virulence genes, phylogenetic groups, multilocus sequence typing (MLST) and PFGE. In the second part of this study, 249 ESBL-producing E. coli isolates (April 2007 to May 2008) were investigated only for the detection of clone O25b:H4-ST131 producing CTX-M-15 using a triplex PCR developed in this study and based on the detection of the new operon afa FM955459 and the targets rfbO25b and 3' end of the bla(CTX-M-15) gene.


RESULTS
Of the 105 ESBL-producing E. coli isolates, 60 (57.1%) were positive for CTX-M-14, 23 (21.9%) for CTX-M-15, 10 (9.5%) for SHV-12 and 7 (6.7%) for CTX-M-32. Serotypes, virulence genes, phylogenetic groups and molecular typing by PFGE demonstrated high homogeneity within those producing CTX-M-15 and high diversity within E. coli producing CTX-M-14 and other ESBLs. By PFGE, CTX-M-15-producing E. coli isolates O25b:H4 belonging to the phylogenetic group B2 and MLST profile ST131 were grouped in the same cluster. The epidemic strain of clone O25b:H4-ST131 represented 23.1%, 22.5% and 20.0% of all ESBL-producing E. coli isolated in 2006, 2007 and 2008, respectively.


CONCLUSIONS
CTX-M-type ESBLs, primarily CTX-M-14 and CTX-M-15, have emerged as the predominant types of ESBL produced by E. coli isolates in Lugo. In view of the reported findings, long-term care facilities for elderly people may represent a significant reservoir for E. coli clone O25b:H4-ST131 producing CTX-M-15. The triplex PCR developed in this work will be useful for rapid and simple detection of this clone.
Departamento de Microbioloxía e Parasitolxía, Universidade de Santiago de Compostela, Lugo, Spain.
Miguel
M
Blanco
Maria Pilar
MP
Alonso
Marie-Hélène
MH
Nicolas-Chanoine
Ghizlane
G
Dahbi
Azucena
A
Mora
Jesús E
JE
Blanco
Cecilia
C
López
Pilar
P
Cortés
Montserrat
M
Llagostera
Véronique
V
Leflon-Guibout
Beatriz
B
Puentes
Rosalía
R
Mamani
Alexandra
A
Herrera
María Amparo
MA
Coira
Fernando
F
García-Garrote
Julia María
JM
Pita
Jorge
J
Blanco
D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics*; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D009876:Operon; D010802:Phylogeny; D015995:Prevalence; D017422:Sequence Analysis, DNA; D012703:Serotyping; D013030:Spain / Q000453:epidemiology; D037521:Virulence Factors / Q000235:genetics; D001618:beta-Lactamases / Q000096:biosynthesis*
D004269:DNA, Bacterial; D037521:Virulence Factors; C473109:beta-lactamase CTX-M-15; D001618:beta-Lactamases