Prevalence and molecular characterization of extended-spectrum-β-lactamase-producing Enterobacteriaceae in a pediatric patient population.
Very little is known about the prevalence and composition of various types of extended-spectrum β-lactamases (ESBL) in pediatric patients. The aims of this study were the following: (i) to determine the prevalence of ESBLs among Enterobacteriaceae in a tertiary-care pediatric population; (ii) to characterize the genetic composition of the identified ESBL enzymes; and (iii) to determine the relative prevalence of CTX-M enzymes and Escherichia coli ST131 strains among ESBL-producing isolates in the same pediatric patient population. Among the 1,430 Enterobacteriaceae isolates screened for elevated MICs to cefotaxime and/or ceftazidime from pediatric patients during a 1-year period, 94 isolates possessed at least one ESBL gene. CTX-M was the most commonly isolated ESBL type, consisting of 74% of all ESBLs versus 27% TEM and 24% SHV enzymes. Sequence analysis and probe-specific real-time PCR revealed that the majority (80%) of the CTX-M-type ESBLs were CTX-M-15 enzymes, followed by CTX-M-14 (17%) and CTX-M-27(2.8%). Multilocus sequence typing (MLST) and repetitive PCR analyses revealed that the relative prevalence of ST131 among ESBL-producing E. coli isolates is 10.2%. This study highlights the growing problem of ESBL resistance in pediatric Enterobacteriaceae isolates and demonstrates a transition toward the predominance of CTX-M-type enzymes among ESBL-producing Enterobacteriaceae organisms causing pediatric infections.
Department of Pathology, Baylor College of Medicine, Houston, Texas, USA,.
Lakshmi
L
Chandramohan
Paula A
PA
Revell
D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002439:Cefotaxime / Q000627:therapeutic use; D002442:Ceftazidime / Q000627:therapeutic use; D002648:Child; D004755:Enterobacteriaceae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D008297:Male; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D015995:Prevalence; D060888:Real-Time Polymerase Chain Reaction; D062606:Tertiary Care Centers; D013781:Texas / Q000453:epidemiology; D001618:beta-Lactamases / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification
D000900:Anti-Bacterial Agents; D007527:Isoenzymes; D002442:Ceftazidime; D001618:beta-Lactamases; D002439:Cefotaxime