Nancy L. Havill

Impact of Hydrogen Peroxide Vapor Room Decontamination on Clostridium difficile Environmental Contamination and Transmission in a Healthcare Setting

OBJECTIVE To determine whether hydrogen peroxide vapor (HPV) decontamination can reduce environmental contamination with and nosocomial transmission of Clostridium difficile. DESIGN A prospective before-after intervention study. SETTING A hospital affected by an epidemic strain of C. difficile. INTERVENTION Intensive HPV decontamination of 5 high-incidence wards followed by hospital-wide decontamination of rooms vacated by patients with C. difficile-associated disease (CDAD). The preintervention period was June 2004 through March 2005, and the intervention period was June 2005 through March 2006. RESULTS Eleven (25.6%) of 43 cultures of samples collected by sponge from surfaces before HPV decontamination yielded C. difficile, compared with 0 of 37 cultures of samples obtained after HPV decontamination (P < .001). On 5 high-incidence wards, the incidence of nosocomial CDAD was significantly lower during the intervention period than during the preintervention period (1.28 vs 2.28 cases per 1,000 patient-days; P = .047). The hospital-wide CDAD incidence was lower during the intervention period than during the preintervention period (0.84 vs 1.36 cases per 1,000 patient-days; P = .26). In an analysis limited to months in which the epidemic strain was present during both the preintervention and the intervention periods, CDAD incidence was significantly lower during the intervention period than during the preintervention period (0.88 vs 1.89 cases per 1,000 patient-days; P = .047). CONCLUSIONS HPV decontamination was efficacious in eradicating C. difficile from contaminated surfaces. Further studies of the impact of HPV decontamination on nosocomial transmission of C. difficile are warranted.

Do Infection Control Measures Work for Methicillin-Resistant Staphylococcus aureus?

OBJECTIVE To review evidence regarding the effectiveness of control measures in reducing transmission of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals. DESIGN Literature review and surveillance cultures of hospitalized patients at high risk for MRSA colonization or infection. SETTING A 500-bed, university-affiliated, community teaching hospital. RESULTS The percentage of nosocomial S. aureus infections caused by MRSA increased significantly between 1982 and 2002, despite the use of various isolation and barrier precaution policies. The apparent ineffectiveness of control measures may be due to several factors including the failure to identify patients colonized with MRSA. For example, cultures of stool specimens submitted for Clostridium difficile toxin assays at one hospital found that 12% of patients had MRSA in their stool, and 41% of patients with unrecognized colonization were cared for without using barrier precautions. Other factors include the use of barrier precaution strategies that do not account for multiple reservoirs of MRSA, poor adherence of healthcare workers (HCWs) to recommended barrier precautions and handwashing, failure to identify and treat HCWs responsible for transmitting MRSA, and importation of MRSA by patients admitted from other facilities. Control programs that include active surveillance cultures (ASCs) of high-risk patients and use of barrier precautions have reduced MRSA prevalence rates and have been cost-effective. Using a staged approach to implementing ASCs can minimize logistic problems. CONCLUSION MRSA control programs are effective if they include ASCs of high-risk patients, use of barrier precautions when caring for colonized or infected patients, hand hygiene, and treating HCWs implicated in MRSA transmission.

Comparison of BD GeneOhm Methicillin-Resistant Staphylococcus aureus (MRSA) PCR versus the CHROMagar MRSA Assay for Screening Patients for the Presence of MRSA Strains

ABSTRACT We compared the BD GeneOhm methicillin-resistant Staphylococcus aureus (MRSA) real-time PCR assay with the CHROMagar MRSA assay for the detection of MRSA in 286 nasal surveillance specimens. Compared with the CHROMagar MRSA assay, PCR had sensitivity, specificity, positive predictive value, and negative predictive values of 100%, 98.6%, 95.8%, and 100%, respectively. The mean PCR turnaround time was 14.5 h.

Terminal Decontamination of Patient Rooms Using an Automated Mobile UV Light Unit

OBJECTIVE To determine the ability of a mobile UV light unit to reduce bacterial contamination of environmental surfaces in patient rooms. METHODS An automated mobile UV light unit that emits UV-C light was placed in 25 patient rooms after patient discharge and operated using a 1- or 2-stage procedure. Aerobic colony counts were calculated for each of 5 standardized high-touch surfaces in the rooms before and after UV light decontamination (UVLD). Clostridium difficile spore log reductions achieved were determined using a modification of the ASTM (American Society for Testing and Materials) International E2197 quantitative disk carrier test method. In-room ozone concentrations during UVLD were measured. RESULTS For the 1-stage procedure, mean aerobic colony counts for the 5 high-touch surfaces ranged from 10.6 to 98.2 colony-forming units (CFUs) per Dey/Engley (D/E) plate before UVLD and from 0.3 to 24.0 CFUs per D/E plate after UVLD, with significant reductions for all 5 surfaces (all [Formula: see text]). Surfaces in direct line of sight were significantly more likely to yield negative culture results after UVLD than before UVLD (all [Formula: see text]). Mean C. difficile spore log reductions ranged from 1.8 to 2.9. UVLD cycle times ranged from 34.2 to 100.1 minutes. For the 2-stage procedure, mean aerobic colony counts ranged from 10.0 to 89.2 CFUs per D/E plate before UVLD and were 0 CFUs per D/E plate after UVLD, with significant reductions for all 5 high-touch surfaces. UVLD cycle times ranged from 72.1 to 146.3 minutes. In-room ozone concentrations during UVLD ranged from undetectable to 0.012 ppm. CONCLUSIONS The mobile UV-C light unit significantly reduced aerobic colony counts and C. difficile spores on contaminated surfaces in patient rooms.

Comparison of Fluorescent Marker Systems with 2 Quantitative Methods of Assessing Terminal Cleaning Practices

OBJECTIVE To compare fluorescent markers with aerobic colony counts (ACCs) and an adenosine triphosphate (ATP) bioluminescence assay system for assessing terminal cleaning practices. DESIGN A prospective observational survey. SETTING A 500-bed university-affiliated community teaching hospital. METHODS In a convenience sample of 100 hospital rooms, 5 high-touch surfaces were marked with fluorescent markers before terminal cleaning and checked after cleaning to see whether the marker had been entirely or partially removed. ACC and ATP readings were performed on the same surfaces before and after terminal cleaning. RESULTS Overall, 378 (76%) of 500 surfaces were classified as having been cleaned according to fluorescent markers, compared with 384 (77%) according to ACC criteria and 225 (45%) according to ATP criteria. Of 382 surfaces classified as not clean according to ATP criteria before terminal cleaning, those with the marker removed were significantly more likely than those with the marker partially removed to be classified as clean according to ATP criteria (P = .003). CONCLUSIONS Fluorescent markers are useful in determining how frequently high-touch surfaces are wiped during terminal cleaning. However, contaminated surfaces classified as clean according to fluorescent marker criteria after terminal cleaning were significantly less likely to be classified as clean according to ACC and ATP assays.

Clinical progression of methicillin-resistant Staphylococcus aureus vertebral osteomyelitis associated with reduced susceptibility to daptomycin.

ABSTRACT Daptomycin, a novel cyclic lipopeptide antibiotic, exhibits rapid bactericidal activity in vitro against most clinically relevant gram-positive organisms, including drug-resistant pathogens. Herein we describe a patient in whom methicillin-resistant Staphylococcus aureus with reduced susceptibility to daptomycin was responsible for bacteremia and progressive vertebral osteomyelitis during daptomycin therapy.

Frequency and Possible Infection Control Implications of Gastrointestinal Colonization with Methicillin-Resistant Staphylococcus aureus

ABSTRACT Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of health care-associated infections. Multiple factors, including transmission from unrecognized reservoirs of MRSA, are responsible for failure to control the spread of MRSA. We conducted prospective surveillance to determine the frequency of gastrointestinal colonization with MRSA among patients and its possible impact on nosocomial transmission of MRSA. Stool specimens submitted for Clostridium difficile toxin A/B assays were routinely inoculated on colistin-naladixic acid agar plates, and S. aureus was identified by using standard methods. Methicillin resistance was confirmed by growth on oxacillin-salt screening agar. For patients whose stool yielded MRSA, information regarding any previous cultures positive for MRSA or other organisms that would require contact precautions was obtained from the laboratorys computer system. During a 1-year period, 151 (9.8%) of 1,543 patients who had one or more stool specimens screened had MRSA in their stool. Ninety-three (62%) of the 151 patients had no previous history of MRSA colonization or infection. Of these 93, 75 were inpatients. Sixty (80%) of the 75 inpatients with no previous history of MRSA were not under “contact precautions.” The 60 patients would have spent an estimated total of 267 days without being placed under contact precautions if their positive stool cultures had not resulted in their being isolated. Placing patients under contact precautions based on their positive stool cultures prevented an estimated 35 episodes of MRSA transmission. We conclude that gastrointestinal colonization with MRSA may serve as an unrecognized reservoir from which transmission of MRSA may occur in health care facilities.

Feasibility of Routinely Using Hydrogen Peroxide Vapor to Decontaminate Rooms in a Busy United States Hospital

During a 22-month period at a 500-bed teaching hospital, 1,565 rooms that had housed patients infected with multidrug-resistant pathogens were decontaminated using hydrogen peroxide vapor. Hydrogen peroxide vapor decontamination required a mean time of 2 hours and 20 minutes, compared with 32 minutes for conventional cleaning. Despite the greater time required for decontamination, hydrogen peroxide vapor decontamination of selected patient rooms is feasible in a busy hospital with a mean occupancy rate of 94%.

Comparison of the Microbiological Efficacy of Hydrogen Peroxide Vapor and Ultraviolet Light Processes for Room Decontamination

OBJECTIVE To compare the microbiological efficacy of hydrogen peroxide vapor (HPV) and ultraviolet radiation (UVC) for room decontamination. DESIGN Prospective observational study. SETTING 500-bed teaching hospital. METHODS HPV and UVC processes were performed in 15 patient rooms. Five high-touch sites were sampled before and after the processes and aerobic colony counts (ACCs) were determined. Carrier disks with ∼10(6) Clostridium difficile (CD) spores and biological indicators (BIs) with 10(4) and 10(6) Geobacillus stearothermophilus spores were placed in 5 sites before decontamination. After decontamination, CD log reductions were determined and BIs were recorded as growth or no growth. RESULTS 93% of ACC samples that had growth before HPV did not have growth after HPV, whereas 52% of sites that had growth before UVC did not have growth after UVC (P < .0001). The mean CD log reduction was >6 for HPV and ∼2 for UVC. After HPV 100% of the 10(4) BIs did not grow, and 22% did not grow after UVC, with a range of 7%-53% for the 5 sites. For the 10(6) BIs, 99% did not grow after HPV and 0% did not grow after UVC. Sites out of direct line of sight were significantly more likely to show growth after UVC than after HPV. Mean cycle time was 153 (range, 140-177) min for HPV and 73 (range, 39-100) min for UVC (P < .0001). CONCLUSION Both HPV and UVC reduce bacterial contamination, including spores, in patient rooms, but HPV is significantly more effective. UVC is significantly less effective for sites that are out of direct line of sight.

Cleanliness of portable medical equipment disinfected by nursing staff

Increased attention has been focused on disinfection by housekeepers, but few data are available on disinfection of equipment by nurses. We used adenosine triphosphate bioluminescence assays and aerobic cultures to assess the cleanliness of portable medical equipment disinfected by nurses between each patient use. We found that the equipment was not being disinfected as per protocol and that education and feedback to nursing are warranted to improve disinfection of medical equipment.