2560. Multispecies outbreak of KPC-2 producing Enterobacteriaceae in a Chilean pediatric hospital
Session: Oral Abstract Session: Genomics and Susceptibility of Superbugs
Saturday, October 6, 2018: 2:30 PM
Room: S 157

Background: Carbapenem-resistant Enterobacteriaceae (CRE) are a critical global health problem. We detected a surge of CRE cases in a pediatric hospital in Chile, a country with a low endemicity of KPC-producing organisms. Herein, we describe the molecular epidemiology of this outbreak.    

Methods: CRE isolates from clinical specimens and surveillance rectal swabs (obtained using chromID CARBA SMART agar, BioMerieux) of pediatric patients were collected from July 2015 Ð January 2017.  Species identity was confirmed by MALDI-TOF. Carbapenemase genes (blaKPC, blaNDM, blaVIM, blaIMP, blaOXA-48-like) were detected by multiplex PCR, followed by amplification and sequencing of the blaKPC allele. Conjugation experiments were conducted with representative species as donors and sodium azide resistant E.coli J53 as recipient. PCR-based plasmid typing (PBRT Diatheva kit) was then performed on donors and recipients. For K. pneumoniae, genetic relatedness was investigated by PFGE, multilocus sequence typing and wzi typing.

Results: Sixty-one CRE clinical and surveillance isolates were obtained from 49 patients aged 17 days to 16 years. blaKPC-2 was present in 57/62 isolates; no other carbapenemases were found. For 11 patients, multiple cultures were obtained; 4/11 had more than one KPC-harboring species. KPC-harboring isolates displayed ertapenem MICs ranging from 1 - >8 mg/L. Preliminary analyses suggest that blaKPC-2 is contained within a non-classical Tn4401 structure (lacking the upstream promoter). Mating experiments indicate that blaKPC-2 is carried by a conjugative IncN backbone plasmid. Interestingly, K. pneumoniae isolates were non-clonal by PFGE and belonged to multiple STs unrelated to CG258 (ST34, ST36, among others) and different wzi types (37, 154, among others).

Conclusion: We report a multispecies outbreak of KPC-2 producing CRE in children mainly driven by horizontal dissemination of a promiscuous IncN plasmid. The non-clonal, multispecies nature of this outbreak provides insights into the complex dynamics of KPC dissemination in countries like Chile, where the clonal spread of highly successful clones like CG258 is not the predominant dissemination vehicle, and instead HGT-related spread could be playing a more important role.

Laura J Rojas, PhD1,2, Steven H Marshall, MS2, Lina M Rivas, MSc.3, Maria Spencer, MSc.3, Joseph Rutter, BS2, Michael R. Jacobs, MD/PhD4,5, Federico Perez, MD, MS2,6,7, Paulina Coria, MD8, Francisca Valdivieso, MD9,10, Rafael Araos Bralic, MD MMSc11, Jose M. Munita, MD3,12 and Robert A. Bonomo, MD1,2,6,13, (1)Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH, (2)Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, (3)Instituto De Ciencias e Innovacion En Medicina (ICIM), Clinica Alemana Universidad del Desarrollo, Santiago, Chile, (4)Microbiology, University Hospitals Cleveland Medical Center, Cleveland, OH, (5)Pathology, Case Western Reserve University, Cleveland, OH, (6)Division of Infectious Diseases and HIV Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, (7)Infectious Diseases Section, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, (8)Unidad De Infectología e Iaas, Hospital Luis Calvo Mackenna, Santiago, Chile, (9)Laboratorio Microbiologia, Hospital Luis Calvo Mackenna, Santiago, Chile, (10)Clinica Alemana, Santiago, Chile, (11)Infectious Diseases, Clinica Alemana Universidad del Desarrollo, Santiago, Chile, (12)Center for Antimicrobial Resistance and Microbial Genomics (CARMiG), University of Texas McGovern Medical School, Houston, TX, (13)Department of Pharmacology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH

Disclosures:

L. J. Rojas, None

S. H. Marshall, None

L. M. Rivas, None

M. Spencer, None

J. Rutter, None

M. R. Jacobs, None

F. Perez, None

P. Coria, None

F. Valdivieso, None

R. Araos Bralic, None

J. M. Munita, None

R. A. Bonomo, None

Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.