TY - JOUR
T1 - Molecular Epidemiology of Ceftriaxone-Nonsusceptible Enterobacterales Isolates in an Academic Medical Center in the United States
AU - Tamma, Pranita D.
AU - Sharara, Sima L.
AU - Pana, Zoi D.
AU - Amoah, Joe
AU - Fisher, Stephanie L.
AU - Tekle, Tsigereda
AU - Doi, Yohei
AU - Simner, Patricia J.
N1 - Funding Information:
Financialsupport.This work was supported by funding from the National Institutes of Health K23-AI127935 awarded to P.D.T.; R01-AI104895, R21-AI123747, R21-AI135522 to Y.D.; and an R21-AI130608 awarded to P.J.S.
Publisher Copyright:
© 2019 The Author(s) 2019. Published by Oxford University Press on behalf of Infectious Diseases Society of America.
PY - 2019/8/1
Y1 - 2019/8/1
N2 - Knowledge of whether Enterobacterales are not susceptible to ceftriaxone without understanding the underlying resistance mechanisms may not be sufficient to direct appropriate treatment decisions. As an example, extended-spectrum β-lactamase (ESBL)-producing organisms almost uniformly display nonsusceptibility to ceftriaxone. Regardless of susceptibility to piperacillin-tazobactam or cefepime, carbapenem antibiotics are the treatment of choice for invasive infections. No such guidance exists for ceftriaxone-nonsusceptible organisms with mechanisms other than ESBL production. We sought to investigate the molecular epidemiology of ceftriaxone-nonsusceptible Enterobacterales. Methods: All consecutive Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, or Proteus mirabilis clinical isolates with ceftriaxone minimum inhibitory concentrations (MICs) of ≥2 mcg/mL from unique patients at a United States hospital over an 8-month period were evaluated for β-lactamase genes using a DNA microarray-based assay. Results: Of 1929 isolates, 482 (25%) had ceftriaxone MICs of ≥2 mcg/mL and were not resistant to any carbapenem antibiotics. Of the 482 isolates, ESBL (blaCTX-M, blaSHV, blaTEM) and/or plasmid-mediated ampC (p-ampC) genes were identified in 376 (78%). ESBL genes were identified in 310 (82.4%), p-ampC genes in 2 (0.5%), and both ESBL and p-ampC genes in 64 (17.0%) of the 376 organisms. There were 211 (56%), 120 (32%), 41 (11%), and 4 (1%) isolates with 1, 2, 3, or ≥4 ESBL or p-ampC genes. The most common ESBL genes were of the blaCTX-M-1 group (includes blaCTX-M-15), and the most common p-ampC gene was blaCMY-2. Conclusions: There is considerable diversity in the molecular epidemiology of ceftriaxone-nonsusceptible Enterobacterales. An understanding of this diversity can improve antibiotic decision-making.
AB - Knowledge of whether Enterobacterales are not susceptible to ceftriaxone without understanding the underlying resistance mechanisms may not be sufficient to direct appropriate treatment decisions. As an example, extended-spectrum β-lactamase (ESBL)-producing organisms almost uniformly display nonsusceptibility to ceftriaxone. Regardless of susceptibility to piperacillin-tazobactam or cefepime, carbapenem antibiotics are the treatment of choice for invasive infections. No such guidance exists for ceftriaxone-nonsusceptible organisms with mechanisms other than ESBL production. We sought to investigate the molecular epidemiology of ceftriaxone-nonsusceptible Enterobacterales. Methods: All consecutive Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, or Proteus mirabilis clinical isolates with ceftriaxone minimum inhibitory concentrations (MICs) of ≥2 mcg/mL from unique patients at a United States hospital over an 8-month period were evaluated for β-lactamase genes using a DNA microarray-based assay. Results: Of 1929 isolates, 482 (25%) had ceftriaxone MICs of ≥2 mcg/mL and were not resistant to any carbapenem antibiotics. Of the 482 isolates, ESBL (blaCTX-M, blaSHV, blaTEM) and/or plasmid-mediated ampC (p-ampC) genes were identified in 376 (78%). ESBL genes were identified in 310 (82.4%), p-ampC genes in 2 (0.5%), and both ESBL and p-ampC genes in 64 (17.0%) of the 376 organisms. There were 211 (56%), 120 (32%), 41 (11%), and 4 (1%) isolates with 1, 2, 3, or ≥4 ESBL or p-ampC genes. The most common ESBL genes were of the blaCTX-M-1 group (includes blaCTX-M-15), and the most common p-ampC gene was blaCMY-2. Conclusions: There is considerable diversity in the molecular epidemiology of ceftriaxone-nonsusceptible Enterobacterales. An understanding of this diversity can improve antibiotic decision-making.
UR - http://www.scopus.com/inward/record.url?scp=85081199608&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85081199608&partnerID=8YFLogxK
U2 - 10.1093/ofid/ofz353
DO - 10.1093/ofid/ofz353
M3 - Article
AN - SCOPUS:85081199608
SN - 2328-8957
VL - 6
JO - Open Forum Infectious Diseases
JF - Open Forum Infectious Diseases
IS - 8
M1 - ofz353
ER -