Modifiable Risk Factors for the Spread of Klebsiella pneumoniae Carbapenemase-Producing Enterobacteriaceae Among Long-Term Acute-Care Hospital Patients.

OBJECTIVE To identify modifiable risk factors for acquisition of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae (KPC) colonization among long-term acute-care hospital (LTACH) patients. DESIGN Multicenter, matched case-control study. SETTING Four LTACHs in Chicago, Illinois. PARTICIPANTS Each case patient included in this study had a KPC-negative rectal surveillance culture on admission followed by a KPC-positive surveillance culture later in the hospital stay. Each matched control patient had a KPC-negative rectal surveillance culture on admission and no KPC isolated during the hospital stay. RESULTS From June 2012 to June 2013, 2,575 patients were admitted to 4 LTACHs; 217 of 2,144 KPC-negative patients (10.1%) acquired KPC. In total, 100 of these patients were selected at random and matched to 100 controls by LTACH facility, admission date, and censored length of stay. Acquisitions occurred a median of 16.5 days after admission. On multivariate analysis, we found that exposure to higher colonization pressure (OR, 1.02; 95% CI, 1.01-1.04; P=.002), exposure to a carbapenem (OR, 2.25; 95% CI, 1.06-4.77; P=.04), and higher Charlson comorbidity index (OR, 1.14; 95% CI, 1.01-1.29; P=.04) were independent risk factors for KPC acquisition; the odds of KPC acquisition increased by 2% for each 1% increase in colonization pressure. CONCLUSIONS Higher colonization pressure, exposure to carbapenems, and a higher Charlson comorbidity index independently increased the odds of KPC acquisition among LTACH patients. Reducing colonization pressure (through separation of KPC-positive patients from KPC-negative patients using strict cohorts or private rooms) and reducing carbapenem exposure may prevent KPC cross transmission in this high-risk patient population. Infect Control Hosp Epidemiol 2017;38:670-677.

Modeling spread of KPC-producing bacteria in long-term acute care hospitals in the Chicago region, USA.

OBJECTIVE: Prevalence of bla KPC-encoding Enterobacteriaceae (KPC) in Chicago long-term acute care hospitals (LTACHs) rose rapidly after the first recognition in 2007. We studied the epidemiology and transmission capacity of KPC in LTACHs and the effect of patient cohorting. METHODS: Data were available from 4 Chicago LTACHs from June 2012 to June 2013 during a period of bundled interventions. These consisted of screening for KPC rectal carriage, daily chlorhexidine bathing, medical staff education, and 3 cohort strategies: a pure cohort (all KPC-positive patients on 1 floor), single rooms for KPC-positive patients, and a mixed cohort (all KPC-positive patients on 1 floor, supplemented with KPC-negative patients). A data-augmented Markov chain Monte Carlo (MCMC) method was used to model the transmission process. RESULTS: Average prevalence of KPC colonization was 29.3%. On admission, 18% of patients were colonized; the sensitivity of the screening process was 81%. The per admission reproduction number was 0.40. The number of acquisitions per 1,000 patient days was lowest in LTACHs with a pure cohort ward or single rooms for colonized patients compared with mixed-cohort wards, but 95% credible intervals overlapped. CONCLUSIONS: Prevalence of KPC in LTACHs is high, primarily due to high admission prevalence and the resultant impact of high colonization pressure on cross transmission. In this setting, with an intervention in place, patient-to-patient transmission is insufficient to maintain endemicity. Inclusion of a pure cohort or single rooms for KPC-positive patients in an intervention bundle seemed to limit transmission compared to use of a mixed cohort.

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

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.

The effectiveness of routine daily chlorhexidine gluconate bathing in reducing Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae skin burden among long-term acute care hospital patients.

We evaluated the effectiveness of daily chlorhexidine gluconate (CHG) bathing in decreasing skin carriage of Klebsiella pneumoniae carbapenemase-producing Enterobacteriaceae (KPC) among long-term acute care hospital patients. CHG bathing reduced KPC skin colonization, particularly when CHG skin concentrations greater than or equal to 128 µg/mL were achieved.

Risk of hand or glove contamination after contact with patients colonized with vancomycin-resistant enterococcus or the colonized patients' environment.

OBJECTIVE: To estimate the level of hand or glove contamination with vancomycin-resistant enterococci (VRE) among healthcare workers (HCWs) who touch a patient colonized with VRE and/or the colonized patient's environment during routine care. DESIGN: Structured observational study. SETTING: Medical intensive care unit of a 700-bed, tertiary-care teaching hospital. PARTICIPANTS: VRE-colonized patients and their caregivers. METHODS: We obtained samples from sites on the intact skin of 22 patients colonized with VRE and samples from sites in the patients' rooms, before and after routine care, during 27 monitoring episodes. A total of 98 unique HCWs were observed during 131 HCW observations. Observers recorded the sites touched by HCWs. Culture samples were obtained from HCWs' hands and gloves before and after care. RESULTS: VRE were isolated from a mean (+/-SD) of 55% +/- 24% of patient sites (n=256) and 17% +/- 12% of environmental sites (n=1,572). Most HCWs (131 [56%]) touched both the patient and the patient's environment; no HCW touched only the patient. Of 103 HCWs whose hand samples were negative for VRE when they entered the room, 52% contaminated their hands or gloves after touching the environment, and 70% contaminated their hands or gloves after touching the patient and the environment (P=.101). In a univariate logistic regression model, the risk of hand or glove contamination was associated with the number of contacts made (odds ratio, 1.1 [95% confidence interval, 1.01-1.19). In a multivariate model, the effect of the number of contacts could not be distinguished from the effect of type of contact (ie, touching the environment alone or touching both the patient and the environment). Overall, 37% of HCWs who did not wear gloves contaminated their hands, and 5% of HCWs who wore gloves did so (an 86% difference). CONCLUSION: HCWs were nearly as likely to have contaminated their hands or gloves after touching the environment in a room occupied by a patient colonized by VRE as after touching the colonized patient and the patient's environment. Gloves were highly protective with respect to hand contamination.

Reduction in acquisition of vancomycin-resistant enterococcus after enforcement of routine environmental cleaning measures.

BACKGROUND: The role of environmental contamination in nosocomial cross-transmission of antibiotic-resistant bacteria has been unresolved. Using vancomycin-resistant enterococci (VRE) as a marker organism, we investigated the effects of improved environmental cleaning with and without promotion of hand hygiene adherence on the spread of VRE in a medical intensive care unit. METHODS: The study comprised a baseline period (period 1), a period of educational intervention to improve environmental cleaning (period 2), a "washout" period without any specific intervention (period 3), and a period of multimodal hand hygiene intervention (period 4). We performed cultures for VRE of rectal swab samples obtained from patients at admission to the intensive care unit and daily thereafter, and we performed cultures of environmental samples and samples from the hands of health care workers twice weekly. We measured patient clinical and demographic variables and monitored intervention adherence frequently. RESULTS: Our study included 748 admissions to the intensive care unit over a 9-month period. VRE acquisition rates were 33.47 cases per 1000 patient-days at risk for period 1 and 16.84, 12.09, and 10.40 cases per 1000 patient-days at risk for periods 2, 3, and 4, respectively. The mean (+/-SD) weekly rate of environmental sites cleaned increased from 0.48+/-0.08 at baseline to 0.87+/-0.08 in period 2; similarly high cleaning rates persisted in periods 3 and 4. Mean (+/-SD) weekly hand hygiene adherence rate was 0.40+/-0.01 at baseline and increased to 0.57+/-0.11 in period 2, without a specific intervention to improve adherence, but decreased to 0.29+/-0.26 in period 3 and 0.43+/-0.1 in period 4. Mean proportions of positive results of cultures of environmental and hand samples decreased in period 2 and remained low thereafter. In a Cox proportional hazards model, the hazard ratio for acquiring VRE during periods 2-4 was 0.36 (95% confidence interval, 0.19-0.68); the only determinant explaining the difference in VRE acquisition was admission to the intensive care unit during period 1. CONCLUSIONS: Decreasing environmental contamination may help to control the spread of some antibiotic-resistant bacteria in hospitals.

Chlorhexidine gluconate to cleanse patients in a medical intensive care unit: the effectiveness of source control to reduce the bioburden of vancomycin-resistant enterococci.

BACKGROUND: Historically, methods of interrupting pathogen transmission have focused on improving health care workers' adherence to recommended infection control practices. An adjunctive approach may be to use source control (eg, to decontaminate patients' skin). METHODS: We performed a prospective sequential-group single-arm clinical trial in a teaching hospital's medical intensive care unit from October 2002 to December 2003. We bathed or cleansed 1787 patients and assessed them for acquisition of vancomycin-resistant enterococci (VRE). We performed a nested study of 86 patients with VRE colonization and obtained culture specimens from 758 environmental surfaces and 529 health care workers' hands. All patients were cleansed daily with the procedure specific to the study period as follows: period 1, soap and water baths; period 2, cleansing with cloths saturated with 2% chlorhexidine gluconate; and period 3, cloth cleansing without chlorhexidine. We measured colonization of patient skin by VRE, health care worker hand or environmental surface contamination by VRE, and patient acquisition of VRE rectal colonization. RESULTS: Compared with soap and water baths, cleansing patients with chlorhexidine-saturated cloths resulted in 2.5 log(10) less colonies of VRE on patients' skin and less VRE contamination of health care workers' hands (risk ratio [RR], 0.6; 95% confidence interval [CI], 0.4-0.8) and environmental surfaces (RR, 0.3; 95% CI, 0.2-0.5). The incidence of VRE acquisition decreased from 26 colonizations per 1000 patient-days to 9 per 1000 patient-days (RR, 0.4; 95% CI, 0.1-0.9). For all measures, effectiveness of cleansing with nonmedicated cloths was similar to that of soap and water baths. CONCLUSION: Cleansing patients with chlorhexidine-saturated cloths is a simple, effective strategy to reduce VRE contamination of patients' skin, the environment, and health care workers' hands and to decrease patient acquisition of VRE.

Transfer of vancomycin-resistant enterococci via health care worker hands.

BACKGROUND: The roles of the contaminated hospital environment and of patient skin carriage in the spread of vancomycin-resistant enterococci (VRE) are uncertain. Transfer of VRE via health care worker (HCW) hands is assumed but unproved. We sought to determine the frequency of VRE transmission from sites in the environment or on patients' intact skin to clean environmental or skin sites via contaminated hands of HCWs during routine care. METHODS: We cultured sites on the intact skin of 22 patients colonized by VRE, as well as sites in the patients' rooms, before and after routine care by 98 HCWs. Observers recorded sites touched by HCWs. Cultures were obtained from HCW hands and/or gloves before and after care. All isolates underwent pulsed-field gel electrophoresis. We defined a transfer to have occurred when a culture-negative site became positive with a VRE pulsotype after being touched by an HCW who had the same pulsotype on his or her hands or gloves and who had previously touched a colonized or contaminated site. RESULTS: Health care workers touched 151 negative sites after touching a site that was positive for VRE. Sixteen negative sites (10.6%) became positive after contact. The percentage of times that contact with a site led to a transfer was highest for antecubital fossae and blood pressure cuffs. CONCLUSIONS: Vancomycin-resistant enterococci were transferred from contaminated sites in the environment or on patients' intact skin to clean sites via HCW hands or gloves in 10.6% of opportunities. Controlling VRE by decontaminating the environment and patients' intact skin may be an important adjunctive infection control measure.