1060. Resistance and Relatedness: Molecular Features of Klebsiella pneumoniae as a Colonizer and Pathogen in Pediatric Patients in Seattle, Washington
Session: Poster Abstract Session: Healthcare-Associated Infections in Children
Saturday, October 22, 2011
Room: Poster Hall B1

Background: Klebsiella pneumoniae has attracted attention due to rapid spread of antibiotic resistance. Found in the natural environment and as a gastrointestinal commensal organism, the significance and molecular characteristics of colonizing K. pneumoniae are not well understood.

Methods: Prospective, observational convenience sample of K. pneumoniae isolates collected from Seattle Children's Hospital between 12/2009 and 12/2010.  "Disease" strains were obtained from patients with active blood and urinary tract infections. "Colonizing" strains were isolated from stool specimens collected during routine clinical care.  All isolates were identified by Vitek GN ID card. Antimicrobial susceptibility was tested by Vitek AST-GN30 or disk diffusion. Genotype evaluation was performed using PCR. Multi-Locus Sequence Typing (MLST) was used to evaluate genetic relatedness.  Clinical data were derived from the medical record.

Results: The frequencies of preexisting conditions and antibiotic exposure were similar in the two groups (Table).  Seven isolates were resistant to 3 or more clinically significant antibiotic classes including 6 in the disease cohort which constituted 3 clonal pairs: 2 pairs of novel sequence types, and one pair representing ST11, previously associated with clonal spread of multidrug resistance (MDR).  The single colonization isolate with MDR represented ST37, previously associated with plasmid-borne (SHV-12, DHA) and ertapenem resistance.  Of the disease cohort, 37 isolates (77%) were from the predominant K. pneumoniae phylogroups, versus just 26 (54.1%) of colonizers.



N= 48 (%)

N= 48 (%)

(Urine =35, Blood=13)

Preexisting condition

36 (75%)

42 (88%)


13 (27%)

10 (21%)


1 (2%)

19 (40%)


12 (25%)

8 (17%)


10 (21%)

5 (10%)

Post- transplantation

12 (25%)

8 (17%)

>2 Courses of antibiotics in last year

20 (42%)

15 (31%)

Conclusion: K. pneumoniae was found to colonize patients with comorbidities and antibiotic exposure. Colonizing strains were similar to disease isolates in their phenotypic and genotypic profiles, however, preliminary analysis suggest disease isolates are more clonal than colonizing isolates, as is the case for the better-characterized E. coli species.

Subject Category: P. Pediatric and perinatal infections

Malaika Little, MD, MPH, Pediatric Infectious Disease, Seattle Childrens Hospital Research Institute, Seattle, WA, Xuan Qin, PhD, Seattle Children's Research Institute, Seattle, WA; Department of Laboratory Medicine, University of Washington, Seattle, WA, Danielle Zerr, MD, MPH, Seattle Children's Hospital Research Institute, Seattle, WA and Scott Weissman, MD, Seattle Childrens Research Institute, Seattle, WA


M. Little, None

X. Qin, None

D. Zerr, Sage products, Inc.: Grant Investigator, Research grant
Vioguard, Ltd.: Grant Investigator, Research grant
NIH/NIAID: Grant Investigator, Research grant

S. Weissman, None

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