title: First Report of Group CTX-M-9 Extended Spectrum Beta-Lactamases in Escherichia coli Isolates from Pediatric Patients in Mexico.
abstract: The aim of this study was to identify the presence of group CTX-M-9 extended spectrum beta-lactamases (ESBL) in clinical Escherichia coli isolates from pediatric patients. A total of 404 non-repeated positive ESBL E. coli isolates were collected from documented clinical infections in pediatric patients over a 2-year period. The identification and susceptibility profiles were determined using an automated system. Isolates that suggested ESBL production based on their resistance profiles to third and fourth generation cephalosporin and monobactam were selected. ESBL production was phenotypically confirmed using a diffusion method with cefotaxime and ceftazidime discs alone and in combination with clavulanic acid. blaESBL gene identification was performed through PCR amplification and sequencing. Pulsed Field Gel Electrophoresis (PFGE) and Multilocus Sequence Typing (MLST) were performed to establish the clonal relationships of the E. coli isolates. CTX-M-9-type ESBLs were detected in 2.5% of the isolates. The subtypes corresponded to blaCTX-M-14 (n = 4) and blaCTX-M-27 (n = 6). Additionally, coexistence with other beta-lactamases was observed. A clonal relationship was established in three isolates; the rest were classified as non-related. We found seven different sequence type (ST) in CTX-M-9- producing E. coli isolates. ST38 was the most frequent. This study is the first report in Mexico to document the presence of group CTX-M-9 ESBLs in E. coli isolates from pediatric patients.
authors.affiliation: Molecular Microbiology Laboratory, Instituto Nacional de Pediatría [INP], Mexico City, Mexico.|Pediatric Infectious Diseases Department, INP, Mexico City, Mexico.
authors.forename: Jocelin
authors.initials: J
authors.lastname: Merida-Vieyra
authors.affiliation: Molecular Microbiology Laboratory, Instituto Nacional de Pediatría [INP], Mexico City, Mexico.|Microbiology Department, Escuela Nacional de Ciencias BioloÂgicas, Instituto PoliteÂcnico Nacional, Mexico City, Mexico.
authors.forename: Agustin
authors.initials: A
authors.lastname: De Colsa
authors.affiliation: Clinical Bacteriology Laboratory, INP, Mexico City, Mexico.
authors.forename: Yair
authors.initials: Y
authors.lastname: Calderon Castañeda
authors.affiliation: Clinical Bacteriology Laboratory, INP, Mexico City, Mexico.
authors.forename: Patricia
authors.initials: P
authors.lastname: Arzate Barbosa
authors.affiliation: Molecular Microbiology Laboratory, Instituto Nacional de Pediatría [INP], Mexico City, Mexico.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Aquino Andrade
mesh_terms: D000293:Adolescent; D002439:Cefotaxime / Q000494:pharmacology*; D002442:Ceftazidime / Q000494:pharmacology*; D018550:Cephalosporin Resistance / Q000187:drug effects / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D052978:Disk Diffusion Antimicrobial Tests; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008800:Mexico; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D002442:Ceftazidime; C412613:CTX-M-9 protein, E coli; D001618:beta-Lactamases; D002439:Cefotaxime