Prevention of colonization and infection by Klebsiella pneumoniae carbapenemase-producing enterobacteriaceae in long-term acute-care hospitals

Abstract

Background: Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae (hereafter "KPC") are an increasing threat to healthcare institutions. Long-term acute-care hospitals (LTACHs) have especially high prevalence of KPC.

Methods: Using a stepped-wedge design, we tested whether a bundled intervention (screening patients for KPC rectal colonization upon admission and every other week; contact isolation and geographic separation of KPC-positive patients in ward cohorts or single rooms; bathing all patients daily with chlorhexidine gluconate; and healthcare-worker education and adherence monitoring) would reduce colonization and infection due to KPC in 4 LTACHs with high endemic KPC prevalence. The study was conducted between 1 February 2010 and 30 June 2013; 3894 patients were enrolled during the preintervention period (lasting from 16 to 29 months), and 2951 patients were enrolled during the intervention period (lasting from 12 to 19 months).

Results: KPC colonization prevalence was stable during preintervention (average, 45.8%; 95% confidence interval [CI], 42.1%-49.5%), declined early during intervention, then reached a plateau (34.3%; 95% CI, 32.4%-36.2%; P<.001 for exponential decline). During intervention, KPC admission prevalence remained high (average, 20.6%, 95% CI, 19.1%-22.3%). The incidence rate of KPC colonization fell during intervention, from 4 to 2 acquisitions per 100 patient-weeks (P=.004 for linear decline). Compared to preintervention, average rates of clinical outcomes declined during intervention: KPC in any clinical culture (3.7 to 2.5/1000 patient-days; P=.001), KPC bacteremia (0.9 to 0.4/1000 patient-days; P=.008), all-cause bacteremia (11.2 to 7.6/1000 patient-days; P=.006) and blood culture contamination (4.9 to 2.3/1000 patient-days; P=.03).

Conclusions: A bundled intervention was associated with clinically important and statistically significant reductions in KPC colonization, KPC infection, all-cause bacteremia, and blood culture contamination in a high-risk LTACH population.

Keywords: Klebsiella pneumoniae carbapenemase; carbapenem-resistant Enterobacteriaceae; healthcare-associated infection; infection prevention; long-term acute-care hospital.

Figure 1.

Stepped-wedge design implementation at the 4 long-term acute-care hospitals (LTACHs) participating in the study. The symbol “0” in an unshaded cell indicates preintervention period. The symbol “X” in a shaded cell indicates intervention period. The start date for the preintervention period varied for each LTACH depending on availability of historical clinical culture data: February 1, 2010 (LTACH C), July 1, 2010 (LTACH B), August 1, 2010 (LTACH A), and November 1, 2010 (LTACH D).

Figure 2.

Prevalence rate of Klebsiella pneumoniae carbapenemase–producing Enterobacteriaceae (KPC) rectal colonization during the preintervention and intervention periods. Each data point in the preintervention period represents the average prevalence across the 4 long-term acute-care hospitals (LTACHs) for 1 semiannual point prevalence survey. Only 2 LTACHs (LTACHs D and C) are included in the week −17 point prevalence survey, as LTACHs A and B were already participating in the intervention at that time. During the intervention period, each data point represents the average prevalence across the 4 LTACHs for 1 every other week point prevalence survey. Data for the first 52 weeks of the intervention are shown. P < .001 for exponential decline in prevalence during the intervention period.

Figure 3.

Incidence rate of Klebsiella pneumoniae carbapenemase–producing Enterobacteriaceae (KPC) rectal colonization during the intervention period. Each data point represents the number of patients who acquired KPC per 100 patient-weeks, averaged over the preceding 2 weeks. Definite incident cases and data for the first 52 weeks during which each of the 4 long-term acute-care hospitals participating in the study are shown. P = .004 for linear decline.

Figure 4.

Effect of the intervention bundle on clinical culture outcomes. Shown are the moving averages of the rates of clinical infections (curved solid lines) and 95% confidence limits (curved hatched lines) for preintervention (open black circles) and intervention (closed red triangles) periods. Each data marker represents average number of clinical cultures at 1 long-term acute-care hospital (LTACH) in 1 month. Trend lines for each period are shown in black (preintervention) or red (intervention) solid bold type. Note the different ranges for y-axis in each panel. A, Klebsiella pneumoniae carbapenemase (KPC) in any clinical culture. B, KPC bloodstream infection. C, Bloodstream infection due to any pathogen. D, Contaminated blood culture.