955. Multi-Center Study of the Molecular Epidemiology of Beta-lactam Resistance in Enterobacteriaceae from Chicago Area Children: A Continuing Update
Session: Oral Abstract Session: Pediatric Epidemiology: Outbreaks and Surveillance
Friday, October 28, 2016: 10:45 AM
Room: 288-290
Background: The emergence of MDR Gram negative infections in children is posing a unique threat to our health care delivery system. Unlike adults, children possess age-specific co-morbidities, altered host defenses, and exhibit different transmission dynamics. Herein, we update the clinical and molecular epidemiology of this emerging pediatric health threat, focusing on ESBL and carbapenemase containing Enterobacteriaceae.

Methods: A retrospective cohort study of 276 GNB isolates from unique patients, phenotypically identified as ESBL or carbapenemase producers, was performed. Isolates from 5 Chicago hospitals were recovered from children ages 0-18 years hospitalized between 2011 and 2015. DNA microarrays (Check-Points™) to detect ESBL, plasmid-mediated AmpC (pAmpC) and carbapenemase type beta-lactamase (bla) genes were used to query the genetic background. Determinants of quinolone resistance (e.g., QRDR and PMFQR) were investigated. MLST and rep-PCR assessed genetic relatedness, and plasmid replicon typing was conducted.

Results: Median age was 4.8 years, 59% were female, and 46% were outpatients. Most isolates (69%) were from urine. E. coli (64%) was most frequently recovered; and of 272 bla genes detected, the most common was blaCTX-M-1 (49%); 1.4% were CRE (3- blaKPC and 1- blaIMP-13). PMFQR was found in 56/82 (62%) and associated with QRDR mutations in 84% of cases. Overall, pAmpC (blaACT/MIR and blaCMY) were found in 12.3% (34/276) of all isolates and in 65% (22/34) of Enterobacter spp. The predominant ST43 E. coli phylogenetic group was B2 (65%) associated with blaCTX-M-1 group (containing blaCTX-M-15) (69%), and contained plasmid replicon types F1A, F11, F1B. The blaKPC harboring K. pneumoniae (Kp) were non ST258 with replicon I1, A/C. Enterobacter carrying blaACT-MIR contained replicon F11A.

Conclusion: Complex bla genotypes were responsible for the ESBL and carbapenem resistant phenotypes. CRE continues to be sporadic, and blaKPC bearing Kp were non ST258; this contrasts with what is usually found in U.S. adults. The finding of a blaIMP-13 reflects the unwelcome emergence of MBLs into the pediatric population. Transmissible plasmid mediated resistance may be the underlying reason for this emerging health threat in Chicago.

Latania K. Logan, MD1,2,3, Andrea M. Hujer, BS2,4, Steve H. Marshall, MS2, T. Nicholas Domitrovic, BA2, Susan D. Rudin, BS4, Felicia a. Scaggs, MD1, Xiaotian Zheng, MD, PhD5,6, Nadia K. Qureshi, MD7, Mary K. Hayden, MD, FIDSA, FSHEA3,8, Anand Karadkhele, MBBS, MPH1, Karen C. Hayani, MD9, Norman M. Jacobs, MD10 and Robert A. Bonomo, MD2,11, (1)Pediatrics, Rush University Medical Center, Chicago, IL, (2)Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, (3)Rush Medical College, Chicago, IL, (4)Case Western Reserve University, Cleveland, OH, (5)Microbiology, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, (6)Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, (7)Pediatrics, Loyola University Medical Center, Maywood, IL, (8)Internal Medicine (Infectious Diseases) and Pathology, Rush University Medical Center, Chicago, IL, (9)Pediatrics, University of Illinois at Chicago, Chicago, IL, (10)Pediatrics, Cook County Health and Hospital Systems, Chicago, IL, (11)Pharmacology, Molecular Biology, and Microbiology, Case Western Reserve University, Cleveland, OH


L. K. Logan, None

A. M. Hujer, None

S. H. Marshall, None

T. N. Domitrovic, None

S. D. Rudin, None

F. A. Scaggs, None

X. Zheng, None

N. K. Qureshi, None

M. K. Hayden, None

A. Karadkhele, None

K. C. Hayani, None

N. M. Jacobs, None

R. A. Bonomo, Merck: Grant Investigator and Scientific Advisor , Consulting fee and Research grant
Actavis: Invited Speaker , Speaker honorarium
Allergan: Grant Investigator , Research grant
Wockhardt: Grant Investigator , Research grant
GlaxoSmithKline: Grant Investigator , Research grant
AstraZeneca: Grant Investigator , Research grant

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