Bleach Disinfection Research Articles

A single-center experience with microbiologic surveillance of LivaNova 3T heater-cooler devices (HCDs)

Background: The global outbreak of Mycobacterium chimaera infections associated with HCDs resulted in new maintenance recommendations. Since 2018, HCDs have been disinfected according to instructions for use (IFU), including twice-monthly bleach disinfection and monitoring hydrogen peroxide (H2O2) to maintain a minimum daily concentration of 100 ppm. In February 2020, the IFU added the recommendation to perform microbiologic surveillance of HCD tank water to ensure effectiveness of disinfection to levels of <1 colony forming unit per milliliter (CFU/mL) of nontuberculous mycobacterium (NTM). We report our experience with this microbiologic surveillance as well as that of culturing the HCD environment to investigate modes of transmission. Methods: In 2022, we began culturing tank water in 10 HCDs for NTM. For a subset of 6 HCDs, quantitative NTM culturing of tank water before and after bleach disinfection was done. After initial results indicated widespread-contamination of HCDs with M. chimaera, we performed fill water cultures from 5 sinks in 4 HCD maintenance rooms. We also conducted 20 two-hour NTM settle-plate cultures of a cardiac operating room (OR) at different sites both inside (n = 7) and outside (n = 3) the OR: 10 with the HCD (located outside the OR) turned off (controls) and 10 with HCD turned on (exposure). A paired t test was used to evaluate differences in mean recovery of NTM in tank water samples. Results: Cultures from 7 (70%) of 10 HCDs were positive, with a mean of 13.6 CFU/mL M. chimaera (Table 1). There was no significant difference between the 10 pairs of pre- and postdisinfection NTM cultures done according to the IFU from 6 HCDs: mean predisinfection cultures (15.5 CFU/mL) versus mean postdisinfection cultures (12 CFU/mL) (P = .90) (Table 2). For fill water, 1 of 7 sink samples in 1 of 4 rooms was positive for M. chimaera ( <1 CFU/mL) from a specimen from a fresh 0.2-µm filter that had been stored in the fill-sink splash zone. OR settle-plate cultures showed 0 (0%) of 10 control sites and 1 (10 %) of 10 exposure sites inside the OR positive for NTM, with a single CFU of M. avium–intracellulare complex. Conclusions: Our data cannot clearly refute either of 2 possible scenarios for HCD contamination: cross contamination during device maintenance versus at the point of manufacture. Despite the IFU guidance or disinfection being implemented, disinfection procedures failed to suppress NTM contamination, and tank water within most HCDs was contaminated with M. chimaera regardless of age or whether it was deep cleaned or upgraded with an aerosol containment device.Disclosures: None

Bleach Emissions Interact Substantially with Surgical and KN95 Mask Surfaces.

Mask wearing and bleach disinfectants became commonplace during the COVID-19 pandemic. Bleach generates toxic species including hypochlorous acid (HOCl), chlorine (Cl2), and chloramines. Their reaction with organic species can generate additional toxic compounds. To understand interactions between masks and bleach disinfection, bleach was injected into a ventilated chamber containing a manikin with a breathing system and wearing a surgical or KN95 mask. Concentrations inside the chamber and behind the mask were measured by a chemical ionization mass spectrometer (CIMS) and a Vocus proton transfer reaction mass spectrometer (Vocus PTRMS). HOCl, Cl2, and chloramines were observed during disinfection and concentrations inside the chamber are 2-20 times greater than those behind the mask, driven by losses to the mask surface. After bleach injection, many species decay more slowly behind the mask by a factor of 0.5-0.7 as they desorb or form on the mask. Mass transfer modeling confirms the transition of the mask from a sink during disinfection to a source persisting >4 h after disinfection. Humidifying the mask increases reactive formation of chloramines, likely related to uptake of ammonia and HOCl. These experiments indicate that masks are a source of chemical exposure after cleaning events occur.

Biocleaning in operating theatres: validation of cleaning techniques by revealing residual traces of blood

In the operating theatre the biocleaning process is essential after each passage to guarantee the non-transmission of potentially pathogenic microbial agents from patient to patient. To evaluate the quality of this biocleaning, the Operational Hygiene Team used a very sensitive method to detect residual traces of blood: luminol (3-aminophthalhydrazide) on the basis of methods used by the police. Luminol was used after conventional one-step biocleaning with the usual detergent/disinfectant, after bleach disinfection before biocleaning, and after biocleaning with a steam cleaner. Lunimol revealed extended traces of blood corresponding to the passage of the strip on the floor, in the corners of the room and on certain pieces of furniture which are difficult to clean. However, no luminescence was detected on the surfaces cleaned by a single passage of the steam cleaner. In all cases, the rooms appeared visually clean and traces of blood only became visible when revealed by luminol. We also showed that usual detergents or disinfectants do not remove blood and instead actually spread it over surfaces that may seem visually clean. These results led us to modify our procedure and also confirmed our wish to generalize the use of the steam cleaning technique for immediate cleaning. Furthermore, our tests show the relevance of luminol as a validation tool for the quality and method of biocleaning.

A prospective multicentre surveillance study to investigate the risk associated with contaminated sinks in the intensive care unit

ObjectivesThe aim was to assess the incidence of sink contamination by multidrug-resistant (MDR) Pseudomonas aeruginosa and Enterobacteriaceae, risk factors for sink contamination and splashing, and their association with clinical infections in the intensive care setting. MethodsA prospective French multicentre study (1 January to 30 May 2020) including in each intensive care unit (ICU) a point-prevalence study of sink contamination, a questionnaire of risk factors for sink contamination (sink use, disinfection procedure) and splashing (visible plashes, distance and barrier between sink and bed), and a 3-month prospective infection survey. ResultsSeventy-three ICUs participated in the study. In total, 50.9% (606/1191) of the sinks were contaminated by MDR bacteria: 41.0% (110/268) of the sinks used only for handwashing, 55.3% (510/923) of those used for waste disposal, 23.0% (62/269) of sinks daily bleached, 59.1% (126/213) of those daily exposed to quaternary ammonium compounds (QACs) and 62.0% (285/460) of those untreated; 459 sinks (38.5%) showed visible splashes and 30.5% (363/1191) were close to the bed (<2 m) with no barrier around the sink. MDR-associated bloodstream infection incidence rates ≥0.70/1000 patient days were associated with ICUs meeting three or four of these conditions, i.e. a sink contamination rate ≥51%, prevalence of sinks with visible splashes ≥14%, prevalence of sinks close to the patient's bed ≥21% and no daily bleach disinfection (6/30 (20.0%) of the ICUs with none, one or two factors vs. 14/28 (50.0%) of the ICUs with three or four factors; p 0.016). DiscussionOur data showed frequent and multifactorial infectious risks associated with contaminated sinks in ICUs.

Implementing Hard Stops in the Electronic Record to Decrease Hospital Acquired C-Diff Infections

<h3>Background</h3> Background: Clostridioides difficile is the leading cause of health care- associated infections. C diff infection data are publicly reported and value- based purchasing can impact a hospital's financial reimbursement if these goals are not met. After experiencing increases in C-diff rates at our organization, testing procedures and patient selection were reviewed. The purpose of our work was to decrease hospital acquired C-diff rates by 30 % by mid-December 2019 through implementing the Centers for Disease Control and Prevention recommendations and Society for Healthcare Epidemiology of America (SHEA) practice guidelines. <h3>Methods</h3> Methods: All adult patients that C diff testing ordered were compared to recommendations by CDC and SHEA. We implemented the following changes to align with the recommendations: isolation at time of suspicion of C diff, daily review of all specimens ordered, automatic cancellation of specimen after 24 hours if not sent, bleach disinfection twice a day on all C diff patients, education of all staff that are involved in patient care, and electronic hard stops for all laxative use and inappropriate testing <h3>Results</h3> Results: These interventions resulted in significant improvement in C-diff rates, and several process measures. C-diff rates decreased from 9.33 per month during the first quarter of calendar year 2019 to an average of 6.8 infections per month during the fourth quarter. All patients with diarrhea on admission began having testing within 48 hours of admission to identify infection and decreased day 4 testing. These processes also eliminated testing with patients receiving laxatives within 48 hours. <h3>Conclusions</h3> Conclusion: Results of this project demonstrate how aligning testing practices with CDC and SHEA guidelines and electronic hard stops can effectively decrease hospital-acquired C-Diff rates. It is recommended organizations adopt standardized practices for testing and utilize available technology to eliminate inappropriate testing and unnecessary treatment.

Efficacy of post-harvest rinsing and bleach disinfection of E. coli O157:H7 on spinach leaf surfaces

Attachment and detachment kinetics of Escherichia coli O157:H7 from baby spinach leaf epicuticle layers were investigated using a parallel plate flow chamber. Mass transfer rate coefficients were used to determine the impact of water chemistry and common bleach disinfection rinses on the removal and inactivation of the pathogen. Attachment mass transfer rate coefficients generally increased with ionic strength. Detachment mass transfer rate coefficients were nearly the same in KCl and AGW rinses; however, the detachment phase lasted longer in KCl than AGW (18 ± 4 min and 4 ± 2 min, respectively), indicating that the ions present during attachment play a significant role in the cells' ability to remain attached. Specifically, increasing bleach rinse concentration by two orders of magnitude was found to increase the detachment mass transfer rate coefficient by 20 times (from 5.7 ± 0.7 × 10−11 m/s to 112.1 ± 26.8 × 10−11 m/s for 10 ppb and 1000 ppb, respectively), and up to 88 ± 4% of attached cells remained alive. The spinach leaf texture was incorporated within a COMSOL model of disinfectant concentration gradients, which revealed nearly 15% of the leaf surface is exposed to almost 1000 times lower concentration than the bulk rinse solution.

An agent-based simulation model for Clostridium difficile infection control.

Control of Clostridium difficile infection (CDI) is an increasingly difficult problem for health care institutions. There are commonly recommended strategies to combat CDI transmission, such as oral vancomycin for CDI treatment, increased hand hygiene with soap and water for health care workers, daily environmental disinfection of infected patient rooms, and contact isolation of diseased patients. However, the efficacy of these strategies, particularly for endemic CDI, has not been well studied. The objective of this research is to develop a valid, agent-based simulation model (ABM) to study C. difficile transmission and control in a midsized hospital. We develop an ABM of a midsized hospital with agents such as patients, health care workers, and visitors. We model the natural progression of CDI in a patient using a Markov chain and the transmission of CDI through agent and environmental interactions. We derive input parameters from aggregate patient data from the 2007-2010 Wisconsin Hospital Association and published medical literature. We define a calibration process, which we use to estimate transition probabilities of the Markov model by comparing simulation results to benchmark values found in published literature. In a comparison of CDI control strategies implemented individually, routine bleach disinfection of CDI-positive patient rooms provides the largest reduction in nosocomial asymptomatic colonization (21.8%) and nosocomial CDIs (42.8%). Additionally, vancomycin treatment provides the largest reduction in relapse CDIs (41.9%), CDI-related mortalities (68.5%), and total patient length of stay (21.6%). We develop a generalized ABM for CDI control that can be customized and further expanded to specific institutions and/or scenarios. Additionally, we estimate transition probabilities for a Markov model of natural CDI progression in a patient through calibration.

Evidence that contaminated surfaces contribute to the transmission of hospital pathogens and an overview of strategies to address contaminated surfaces in hospital settings

Evidence that contaminated surfaces contribute to the transmission of hospital pathogens comes from studies modeling transmission routes, microbiologic studies, observational epidemiologic studies, intervention studies, and outbreak reports. This review presents evidence that contaminated surfaces contribute to transmission and discusses the various strategies currently available to address environmental contamination in hospitals.

Preventing hepatitis C virus infection in injection drug users: risk reduction is not enough

Preventing hepatitis C virus infection in injection drug users: risk reduction is not enough

Access to highly active antiretroviral therapy for injection drug users: adherence, resistance, and death

Injection drug users (IDUs) continue to comprise a major risk group for HIV infection throughout the world and represent the focal population for HIV epidemics in Asia and Eastern Europe/Russia. HIV prevention programs have ranged from HIV testing and counseling, education, behavioral and network interventions, drug abuse treatment, bleach disinfection of needles, needle exchange and expanded syringe access, as well as reducing transition to injection and primary substance abuse prevention. With the advent of highly active antiretroviral therapy (HAART) in 1996, dramatic clinical improvements have been seen. In addition, the treatment's impact on reducing HIV viral load (and therefore transmission by all routes) provides a stronger rationale for an expansion of the focus on prevention to emphasize early identification and treatment of HIV infected individuals. However, treatment of IDUs has many challenges including adherence, resistance and relapse to high risk behaviors, all of which impact issues of access and ultimately effectiveness of potent antiretroviral treatment. A major current challenge in addressing the HIV epidemic revolves around an appropriate approach to HIV treatment for IDUs.

Does bleach disinfection of syringes protect against hepatitis C infection among young adult injection drug users?

Hepatitis C virus (HCV) has emerged as a major public health problem among injection drug users. In this analysis we examine whether disinfection of syringes with bleach has a potentially protective effect on anti-HCV seroconversion. We conducted a nested case-control study comparing 78 anti-HCV seroconverters with 390 persistently anti-HCV seronegative injection drug users. These data come from the Second Collaborative Injection Drug Users Study, a prospective cohort study that recruited injection drug users from five U.S. cities between 1997 and 1999. We used conditional logistic regression to determine the effect of bleach disinfection of syringes on anti-HCV seroconversion. Participants who reported using bleach all the time had an odds ratio (OR) for anti-HCV seroconversion of 0.35 (95% confidence interval = 0.08-1.62), whereas those reporting bleach use only some of the time had an odds ratio of 0.76 (0.21-2.70), when compared with those reporting no bleach use. These results suggest that bleach disinfection of syringes, although not a substitute for use of sterile needles or cessation of injection, may help to prevent HCV infection among injection drug users.

Injection Drug Users' Reactions to Guidelines for Bleach Disinfection of Needles and Syringes: Implications for HIV Prevention

The objective was to determine injection drug users' (IDUs) reactions to and willingness to adopt new National Institute on Drug Abuse, Center for Substance Abuse Treatment, and Centers for Disease Control provisional guidelines for bleach disinfection of needles and syringes (NS). In 1993, 154 IDUs participated in 17 focus groups in 8 U.S. cities. Process evaluations of transcriptions were completed utilizing qualitative techniques. Active IDUs expressed willingness to adopt most new recommendations. Syringe agitation and use of full strength bleach were acceptable. Pre-bleach water rinse, complete filling of the NS, post-bleach rinsing with fresh water, and longer bleach contact times were possible under favorable injection conditions. Cleaning both before and after injection and disassembling the NS for cleaning were unlikely to be adopted. Multiple barriers to consistent bleach use were identified. IDUs were willing to attempt new guidelines, but many circumstances interfere with adequate bleach disinfection. To avoid HIV exposure, increased access to sterile NS is necessary. Implications for HIV prevention are discussed.