Final Summary of Community-Wide Laboratory Surveillance of Carbapenem-Resistant Klebsiella Pneumoniae (CRKP) - Los Angeles County, 2010-2012

BACKGROUND:  CRKP is an emerging multidrug resistant pathogen and the most frequently isolated species of carbapenem-resistant Enterobacteriaceae in the United States. CRKP has caused large nosocomial outbreaks and become endemic in certain hospitals on the East Coast, subsequently spreading across the United States. CRKP were thought to be rare and sporadic in Los Angeles County (LAC); however actual prevalence in LAC is unknown. Because CRKP could give rise to pan-resistant Klebsiella pneumoniae(KP), we initiated community-wide passive surveillance.

METHODS:  LAC declared CRKP a laboratory-reportable disease from June 1 2010 – July 31 2012.  Laboratory directors of all 102 LAC acute care hospitals (ACHs) and 5 reference laboratories were instructed to submit susceptibility testing results for patients who test positive for CRKP. CRKP was defined as a KP isolate with resistance to carbapenems by Clinical and Laboratory Standards Institute criteria. CRKP isolates from the same patient in the same calendar month were excluded.

RESULTS:  A total of 2558 reports were received from 99 laboratories;  2163 (84.6%) met the case definition. Cases that did not meet the case definition were primarily misclassified carbapenem-susceptible extended-spectrum β-lactamase producers (ESBL). Eighty-six of the 102 LAC ACHs reported at least one case. A third of the confirmed (664) cases were reported from the nine LAC long-term acute care hospitals (LTACs); an outbreak in one LTAC facility was identified. Half of hospital reported cases (989, 45.7%) were admitted from skilled nursing facilities (SNFs); 146 (6.7%) were reported directly from SNFs. The mean age of cases was 72 years (range 5 weeks-103 years);  53.6%  were female. A quarter of cases (512) were modified Hodge test positive.  One patient, who had received prior medical care in Pakistan, was positive for New Delhi metallo-beta-lactamase (NDM-1). The 5-week old case was admitted for poor feeding and diarrhea; the case recovered uneventfully and was discharged home.

CONCLUSIONS: This two year laboratory surveillance showed CRKP is more prevalent in LAC, especially in the long term care community, than suspected. Given their smaller bed size relative to ACHs, the more frequent reporting of cases from LTACs highlights an unmet infection control need.  Heightened awareness of this problem is needed in SNFs and LTACs, as these patients tend to transfer frequently between these and other healthcare facilities.