AmpC beta-lactamases in Escherichia coli: emergence of CMY-2-producing virulent phylogroup D isolates belonging mainly to STs 57, 115, 354, 393, and 420, and phylogroup B2 isolates belonging to the international clone O25b-ST131.
Cephalosporins resistance is increasing in Escherichia coli in Spain. We characterize infections by E. coli with reduced susceptibility to third-generation cephalosporins (3GCs) with the AmpC phenotype. Between January 2004 and March 2007, 121 E. coli isolates with the AmpC phenotype were collected (4.8% of all the 2538 E. coli isolates with reduced susceptibility to 3GCs). These isolates were further characterized by clinical and molecular analysis. Plasmid-encoded ampC genes were detected in 46 (38%) isolates (43 CMY-2); 75 isolates (62%) had modifications in the chromosomal ampC promoter region (c-AmpC). CMY-2 producers belonged primarily to the more virulent phylogroup D (48.4%), whereas most isolates of c-AmpC belonged to phylogroup A (56.4%). Bacteremia and infections in children were more frequently produced by CMY-2 producers. CMY-2-producing phylogroup D E. coli belonged to 8 multilocus sequence typing types. Three CMY-2 producers belonged to O25b/ST131/B2 clone. Infections caused by E. coli with the AmpC phenotype may be spreading primarily because of CMY-2-producing phylogroup D isolates, although this enzyme was also detected in the O25b/ST131/B2 clone.
Oteo
Jesús
J
Antibiotic Laboratory, Bacteriology Service, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain. jesus.oteo@isciii.es
Cercenado
Emilia
E
Cuevas
Oscar
O
Bautista
Verónica
V
Delgado-Iribarren
Alberto
A
Orden
Beatriz
B
Pérez-Vázquez
María
M
García-Cobos
Silvia
S
Campos
José
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000145:classification / Q000235:genetics; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004926:Escherichia coli / Q000145:classification* / Q000201:enzymology* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods; D008875:Middle Aged; D017720:Molecular Epidemiology; D015995:Prevalence; D013030:Spain / Q000453:epidemiology; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000145:classification / Q000235:genetics
D001426:Bacterial Proteins; C048795:AmpC beta-lactamases; D001618:beta-Lactamases