Community-wide Laboratory Surveillance of Carbapenem-Resistant Klebsiella pneumoniae (CRKP) - Los Angeles County 2010

SHEA 2011 Abstract

Community-wide Laboratory Surveillance of Carbapenem-Resistant Klebsiella pneumoniae (CRKP) -  Los Angeles County 2010

Background: CRKP is an emerging multidrug resistant pathogen and the most frequently isolated species of carbapenem-resistant Enterobacteriaceae in the United States. CRKP infection is associated with higher mortality, longer hospital stay, and increased costs. CRKP has caused large nosocomial outbreaks and become endemic in certain hospitals on the East Coast since 2001, 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.

 

Objective: To establish a surveillance system for CRKP and describe characteristics of patients with CRKP in LAC.

Methods: LAC declared CRKP a laboratory-reportable disease on June 1, 2010.  Laboratory directors of all 102 LAC acute care hospitals 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 or modified Hodge test. Repeat isolates of CRKP from the same patient within 4 weeks of initial culture were excluded. All antimicrobial susceptibility reports were reviewed to ensure they met the case definition. 

Results: A total of 220 reports were received from June 1 to November 1, 2010 from 38 laboratories, with 164 meeting the case definition. Cases that did not meet the case definition were primarily misclassified carbapenem-susceptible extended-spectrum β-lactamase producers (ESBL). Seventy-seven (46%) isolates were reported from the seven LAC long-term acute care hospitals (LTACs); an outbreak in one LTAC facility was identified. Sixty-two (38%) isolates were found in patients who were residents of skilled nursing facilities (SNF). The mean age of patients with CRKP was 73 years (range 1-99 years); over half were female (93, 57%). Seven laboratories reported 25 (15%) modified Hodge test positive isolates.  Three isolates were both carbapenem-resistant and ESBL positive. One patient, who had received prior medical care in Pakistan, was positive for New Delhi metallo-beta-lactamase (NDM-1).

Conclusions: CRKP is more prevalent in LAC than suspected. Confusion exists among laboratorians about the difference between carbapenemase and ESBL-mediated resistance. Cases were more frequently reported from LTACs than acute care facilities.  Heightened awareness of this problem is needed in SNFs and LTACs, as these patients tend to travel frequently between these and other healthcare facilities.