Community Origins and Regional Differences Highlight Risk of Plasmid-mediated Fluoroquinolone Resistant Enterobacteriaceae Infections in Children

<jats:sec> <jats:title>Background:</jats:title> <jats:p>Fluoroquinolones are uncommonly prescribed in children, yet pediatric multidrug resistant (MDR) enterobacteriaceae (Ent) infections often reveal fluoroquinolone resistance (FQR). We sought to define the molecular epidemiology of FQR and MDR-Ent in children.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods:</jats:title> <jats:p>A case–control analysis of children with MDR-Ent infections at 3 Chicago hospitals was performed. Cases were children with third-generation cephalosporin-resistant and/or carbapenem-resistant Ent infections. Polymerase chain reaction and DNA analysis assessed <jats:italic toggle="yes">bla</jats:italic> and plasmid-mediated FQR (PMFQR) genes. Controls were children with third-generation cephalosporin, fluoroquinolone, and carbapenem-susceptible Ent infections matched by age, source and hospital. We assessed clinical-epidemiologic predictors of PMFQR Ent infection.</jats:p> </jats:sec> <jats:sec> <jats:title>Results:</jats:title> <jats:p>Of 169 third-generation cephalosporin-resistant and/or carbapenem-resistant Ent isolates from children (median age, 4.8 years), 85 were FQR; 56 (66%) contained PMFQR genes. The predominant organism was <jats:italic toggle="yes">Escherichia coli</jats:italic>, and most common <jats:italic toggle="yes">bla</jats:italic> gene <jats:italic toggle="yes">bla</jats:italic> <jats:sub>CTX-M-1</jats:sub> group. In FQR isolates, PMFQR gene mutations included <jats:italic toggle="yes">aac6’1bcr</jats:italic>, <jats:italic toggle="yes">oqxA/B, qepA</jats:italic> and <jats:italic toggle="yes">qnrA/B/D/S</jats:italic> in 83%, 15%, 13% and 11% of isolates, respectively. FQR <jats:italic toggle="yes">E. coli</jats:italic> was often associated with phylogroup B2, ST43/ST131. On multivariable analysis, PMFQR Ent infections occurred mostly in outpatients (odds ratio, 33.1) of non–black-white-Hispanic race (odds ratio, 6.5). Residents of Southwest Chicago were >5 times more likely to have PMFQR Ent infections than those in the reference region, while residence in Central Chicago was associated with a 97% decreased risk. Other demographic, comorbidity, invasive-device, antibiotic use or healthcare differences were not found.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions:</jats:title> <jats:p>The strong association of infection with MDR organisms showing FQR with patient residence rather than with traditional risk factors suggests that the community environment is a major contributor to spread of these pathogens in children.</jats:p> </jats:sec>