Evaluation of antibiotic-resistant bacteria in home kitchens and bathrooms: Is there a link between home disinfectant use and antibiotic resistance?

OBJECTIVE: To determine the relationship between home disinfectant use and the prevalence of antibiotic resistance among environmental isolates of human pathogens. METHODS: Bacteria were cultured from 5 kitchen and 5 bathroom sites using quantitative methods. Antibiotic susceptibility was determined by standard methods. Home disinfectant use was assessed via a questionnaire. RESULTS: The overall total mean log10 counts (total CFU) for the kitchen and bathroom were 4.31 and 4.88, respectively. Gram-positive bacteria were more common in the bathroom (4.05) than in the kitchen (3.60), while Gram-negative bacilli were more common in the kitchen (4.23) than in the bathroom (3.86). The sink and bath drains were the most contaminated sites with 6.16-log10 of total CFU and 6.6-log10 in the kitchen and bathroom, respectively. Households reported cleaning frequency with a variety of commercial products. Most respondents used antibacterial products (eg, soaps, surface disinfectants) in the home. Antibiotic-resistant pathogens were infrequently isolated in the homes evaluated. CONCLUSIONS: Compared to pathogens causing community-acquired clinical infections in the ICARE study, pathogens isolated from households are less likely to demonstrate antibiotic resistance. In addition, no relationship between antibacterial use or frequency of cleaning or disinfection and antibiotic resistance was revealed.

Does blood on "dirty" instruments interfere with the effectiveness of sterilization technologies?

We evaluated the robustness of sterilization technologies when spores and bacteria were placed on "dirty" instruments and overlaid with blood. The results illustrate that steam sterilization is the most effective sterilization technology with the largest margin of safety, followed by ethylene oxide and hydrogen peroxide gas plasma.

Inactivation of Candida auris and Candida albicans by ultraviolet-C.

We evaluated the ability of an ultraviolet-C (UV-C) room decontamination device to kill Candida auris and C. albicans. With an organic challenge (fetal calf serum), the UV-C device demonstrated the following log10 reductions for C. auris of 4.57 and for C. albicans of 5.26 with direct line of sight, and log10 reductions for C. auris of 2.41 and for C. ablicans of 3.96 with indirect line of sight.

Microbial Assessment of Health Care-Associated Pathogens on Various Environmental Sites in Patient Rooms After Terminal Room Disinfection.

We examined the microbial burden on hospital room environmental sites after standard (quaternary ammonium [Quat]) or enhanced disinfection (quat/ultraviolet light [UV-C], bleach, or bleach/UV-C). An enhanced terminal room disinfection reduced the microbial burden of epidemiologically important pathogens on high-touch surfaces in patient rooms, especially sites around the bed, better than standard room disinfection.

Perioperative Bacterial Contamination From Patients on Contact Precaution in Operating Room Environment.

We investigated the microbial burden on the operating room environment when patients on contact precautions for a multidrug-resistant pathogen received surgery. Our study demonstrated that the perioperative environment was contaminated with aerobic bacteria and methicillin-resistant Staphylococcus aureus (MRSA) after surgery, and that MRSA persisted environmentally even after cleaning and disinfection, highlighting the need for meticulous cleaning and disinfection in the perioperative environment.

Comparative evaluation of the microbicidal activity of low-temperature sterilization technologies to steam sterilization.

OBJECTIVE: To compare the microbicidal activity of low-temperature sterilization technologies (vaporized hydrogen peroxide [VHP], ethylene oxide [ETO], and hydrogen peroxide gas plasma [HPGP]) to steam sterilization in the presence of salt and serum to simulate inadequate precleaning. METHODS: Test carriers were inoculated with Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, vancomycin-resistant Enterococcus, Mycobacterium terrae, Bacillus atrophaeus spores, Geobacillus stearothermophilus spores, or Clostridiodes difficile spores in the presence of salt and serum and then subjected to 4 sterilization technologies: steam, ETO, VHP and HPGP. RESULTS: Steam, ETO, and HPGP sterilization techniques were capable of inactivating the test organisms on stainless steel carriers with a failure rate of 0% (0 of 220), 1.9% (6 of 310), and 1.9% (5 of 270), respectively. The failure rate for VHP was 76.3% (206 of 270). CONCLUSION: Steam sterilization is the most effective and had the largest margin of safety, followed by ETO and HPGP, but VHP showed much less efficacy.

Antimicrobial activity of a continuously active disinfectant against healthcare pathogens.

A novel disinfectant studied using an EPA protocol demonstrated sustained antimicrobial activity (ie, 3-5 log10 reduction) in 5 minutes after 24 hours for Staphylococcus aureus, vancomycin-resistant Enterococcus, Candida auris, carbapenem-resistant Escherichia coli and antibiotic-susceptible E. coli, and Enterobacter spp. Only ∼2 log10 reduction occurred with carbapenem-resistant Enterobacter spp and K. pneumoniae, and antibiotic-susceptible K. pneumoniae.

Susceptibility of Candida auris and Candida albicans to 21 germicides used in healthcare facilities.

Candida auris is an emerging fungal pathogen that is often resistant to major classes of antifungal drugs. It is considered a serious global health threat because it can cause severe infections with frequent mortality in more than a dozen countries. It can survive on healthcare environmental surfaces for at least 7 days and can cause outbreaks in healthcare facilities. Clearly, infection prevention strategies, such as surface disinfection, will be essential to controlling Candida transmission. Unfortunately, data on the activity of antiseptics and disinfectants used in healthcare to inactivate this pathogen are limited.1-5 In this study, we investigated 12 different disinfectants (ie, 8 low- and intermediate-level disinfectants in 2 dilutions of sodium hypochlorite and 5 high-level disinfectants/chemical sterilants) and 9 antiseptics commonly used in healthcare facilities for their antimicrobial activity against C. auris and C. albicans.

A prospective study of transmission of Multidrug-Resistant Organisms (MDROs) between environmental sites and hospitalized patients-the TransFER study.

OBJECTIVE: Hospital environmental surfaces are frequently contaminated by microorganisms. However, the causal mechanism of bacterial contamination of the environment as a source of transmission is still debated. This prospective study was performed to characterize the nature of multidrug-resistant organism (MDRO) transmission between the environment and patients using standard microbiological and molecular techniques. SETTING: Prospective cohort study at 2 academic medical centers. DESIGN: A prospective multicenter study to characterize the nature of bacterial transfer events between patients and environmental surfaces in rooms that previously housed patients with 1 of 4 'marker' MDROs: methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Clostridium difficile, and MDR Acinetobacter baumannii. Environmental and patient microbiological samples were obtained on admission into a freshly disinfected inpatient room. Repeat samples from room surfaces and patients were taken on days 3 and 7 and each week the patient stayed in the same room. The bacterial identity, antibiotic susceptibility, and molecular sequences were compared between organisms found in the environment samples and patient sources. RESULTS: We enrolled 80 patient-room admissions; 9 of these patients (11.3%) were asymptomatically colonized with MDROs at study entry. Hospital room surfaces were contaminated with MDROs despite terminal disinfection in 44 cases (55%). Microbiological Bacterial Transfer events either to the patient, the environment, or both occurred in 12 patient encounters (18.5%) from the microbiologically evaluable cohort. CONCLUSIONS: Microbiological Bacterial Transfer events between patients and the environment were observed in 18.5% of patient encounters and occurred early in the admission. This study suggests that research on prevention methods beyond the standard practice of room disinfection at the end of a patient's stay is needed to better prevent acquisition of MDROs through the environment.

Enhanced disinfection leads to reduction of microbial contamination and a decrease in patient colonization and infection.

In this prospective study, we monitored 4 epidemiologically important pathogens (EIPs): methicillin-resistane Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Clostridium difficile, and multidrug-resistant (MDR) Acinetobacter to assess the effectiveness of 3 enhanced disinfection strategies for terminal room disinfection against standard practice. Our data demonstrated that a decrease in room contamination with EIPs of 94% was associated with a 35% decrease in subsequent patient colonization and/or infection.

Antimicrobial activity of a continuous visible light disinfection system.

We evaluated the ability of high-intensity visible violet light with a peak output of 405 nm to kill epidemiologically important pathogens. The high irradiant light significantly reduced both vegetative bacteria and spores at some time points over a 72-hour exposure period.

Understanding the effect of ultraviolet light intensity on disinfection performance through the use of ultraviolet measurements and simulation.

We measured the disinfection of MRSA and Clostridium difficile spores using an ultraviolet C (UV-C) device, and we correlated those results to measurements and computer simulations of UV-C surface intensity. The results demonstrate both large differences in UV light intensity across various surfaces and how this leads to significant differences in disinfection.

Germicidal Activity against Carbapenem/Colistin-Resistant Enterobacteriaceae Using a Quantitative Carrier Test Method.

Susceptibility to germicides for carbapenem/colistin-resistant Enterobacteriaceae is poorly described. We investigated the efficacy of multiple germicides against these emerging antibiotic-resistant pathogens using the disc-based quantitative carrier test method that can produce results more similar to those encountered in health care settings than a suspension test. Our study results demonstrated that germicides commonly used in health care facilities likely will be effective against carbapenem/colistin-resistant Enterobacteriaceae when used appropriately in health care facilities.

Epidemiologic characteristics of health care-associated outbreaks and lessons learned from multiple outbreak investigations with a focus on the usefulness of routine molecular analysis.

BACKGROUND: Single outbreaks have often been reported in health care settings, but the frequency of outbreaks at a hospital over time has not been described. We examined epidemiologic features of all health care-associated outbreak investigations at an academic hospital during a 5-year period. METHODS: Health care-associated outbreak investigations at an academic hospital (2012-2016) were retrospectively reviewed through data on comprehensive hospital-wide surveillance and pulsed-field gel electrophoresis (PFGE) analysis. RESULTS: Fifty-one health care-associated outbreaks (annual range, 8-15), including 26 (51%) outbreaks in intensive care units (ICUs), and 263 infected-colonized patients involved in these outbreaks were identified. The frequency of pathogens varied by affected location, specifically multidrug-resistant organisms (20/26 outbreaks, 77% in ICUs vs 2/25 outbreaks, 8% in non-ICUs; P < .0001) and gastroenteritis because of Clostridium difficile, norovirus, or adenovirus (1/26 outbreaks, 4% in ICUs vs 17/25 outbreaks, 68% in non-ICUs; P < .0001). Outbreaks occurred in approximately one-third of all units (37%) with some repeated instances of the same pathogens. Of 16 outbreaks caused by a bacterial pathogen evaluated by PFGE, 12 (75%) included some indistinguishable strains, suggesting person-to-person transmission or a common source. CONCLUSIONS: This study demonstrated epidemiologic characteristics of multiple outbreaks between ICUs and non-ICUs and the value of molecular typing in understanding the epidemiology of health care-associated outbreaks.

Enhanced terminal room disinfection and acquisition and infection caused by multidrug-resistant organisms and Clostridium difficile (the Benefits of Enhanced Terminal Room Disinfection study): a cluster-randomised, multicentre, crossover study.

BACKGROUND: Patients admitted to hospital can acquire multidrug-resistant organisms and Clostridium difficile from inadequately disinfected environmental surfaces. We determined the effect of three enhanced strategies for terminal room disinfection (disinfection of a room between occupying patients) on acquisition and infection due to meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, C difficile, and multidrug-resistant Acinetobacter. METHODS: We did a pragmatic, cluster-randomised, crossover trial at nine hospitals in the southeastern USA. Rooms from which a patient with infection or colonisation with a target organism was discharged were terminally disinfected with one of four strategies: reference (quaternary ammonium disinfectant except for C difficile, for which bleach was used); UV (quaternary ammonium disinfectant and disinfecting ultraviolet [UV-C] light except for C difficile, for which bleach and UV-C were used); bleach; and bleach and UV-C. The next patient admitted to the targeted room was considered exposed. Every strategy was used at each hospital in four consecutive 7-month periods. We randomly assigned the sequence of strategies for each hospital (1:1:1:1). The primary outcomes were the incidence of infection or colonisation with all target organisms among exposed patients and the incidence of C difficile infection among exposed patients in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT01579370. FINDINGS: 31 226 patients were exposed; 21 395 (69%) met all inclusion criteria, including 4916 in the reference group, 5178 in the UV group, 5438 in the bleach group, and 5863 in the bleach and UV group. 115 patients had the primary outcome during 22 426 exposure days in the reference group (51·3 per 10 000 exposure days). The incidence of target organisms among exposed patients was significantly lower after adding UV to standard cleaning strategies (n=76; 33·9 cases per 10 000 exposure days; relative risk [RR] 0·70, 95% CI 0·50-0·98; p=0·036). The primary outcome was not statistically lower with bleach (n=101; 41·6 cases per 10 000 exposure days; RR 0·85, 95% CI 0·69-1·04; p=0·116), or bleach and UV (n=131; 45·6 cases per 10 000 exposure days; RR 0·91, 95% CI 0·76-1·09; p=0·303) among exposed patients. Similarly, the incidence of C difficile infection among exposed patients was not changed after adding UV to cleaning with bleach (n=38 vs 36; 30·4 cases vs 31·6 cases per 10 000 exposure days; RR 1·0, 95% CI 0·57-1·75; p=0·997). INTERPRETATION: A contaminated health-care environment is an important source for acquisition of pathogens; enhanced terminal room disinfection decreases this risk. FUNDING: US Centers for Disease Control and Prevention.