Risk Factors for Colonization with Carbapenem-Resistant Klebsiella pneumoniae (CRKP) among Past CRKP Carriers in Post Acute Care Facilities (PACF) in Israel

Background: Since 2006, a nationwide outbreak of CRKP has been reported in acute care hospitals in Israel.  We previously performed a point-prevalence study in Israeli PACF and reported a carrier prevalence of 17% among residents.  Objective: To assess risk factors for continued CRKP colonization among past carriers in the PACF population Methods: A point-prevalence study was conducted in 12 PACF. Rectal swabs were obtained from 129 residents with a history of CRKP carriage in 33 wards. Suspicious colonies growing on CHROMagar KPC plates were speciated and tested for carbapenem susceptibilities by VITEK 2 supplemented by Etest.  KPC PCR was performed on broth for all negative cultures.  Patient data collected from medical records included demographic characteristics, comorbid conditions, presence of skin lesions, presence of invasive devices, antibiotic exposure, number of colonized roommates, and time elapsed since first positive CRKP culture.

Results: Of 129 prior CRKP carriers (median age 76, 43% male), colonization was detected in 66 (51%).  Factors associated with CRKP carriage in univariate analysis were residence on a skilled nursing care ward, being cohorted with other CRKP carriers, hospitalization in the prior 6 months, antibiotic exposures during the prior 3 months, presence of an invasive device, and time elapsed since first culture of CRKP.  Among 48 pts screened ≤ 3 months from the 1st culture, 33 (69%) were CRKP-positive vs 30 of 78 pts (38%) screened after >3 months (p=0.001). In multivariable analysis, independent risk factors for CRKP carriage were antibiotic exposure during the prior 3 months, (OR=3.6; CI 1.3-10.0; P=0.014), amoxicillin-clavulanate exposure during the past month (OR=12.5; CI 1.5-101.8; P=0.018 ), and screening within 90 days of the first CRKP culture (OR=3.0; CI 1.3-6.8; P=0.009).

Conclusions: Among prior CRKP carriers in PACF, risk factors for continued colonization are antibiotic exposure and CRKP culture within the past three months.