The Biocide Chlorine Dioxide Stimulates Biofilm Formation in Bacillus subtilis by Activation of the Histidine Kinase KinC
MOSHE SHEMESH, ROBERTO KOLTER, RICHARD LOSICKAMERICAN SOCIETY FOR MICROBIOLOGY, JOURNAL OF BACTERIOLOGY, DECEMBER 2010 IntroductionThe goal of this study was to examine how biofilm formation is stimulated by chlorine dioxide, a chemical that is typically very effective and fast-acting against bacteria. The study examined how chlorine dioxide works and how the biofilm acts as a protector of cells. ResultsThe findings showed that chlorine dioxide accelerated biofilm formation and stimulated matrix gene transcription. The more matrix genes that are transcribed, the easier it is for the biofilm to grow and spread. The study suggested that disruptions in the membrane caused by chlorine dioxide are recognized as a stress signal by KinC, an essential membrane-bound enzyme, prompting biofilm formation. ConclusionSublethal doses of chlorine dioxide can increase the rate of biofilm formation for Bacillus subtilis and other bacteria. Chlorine dioxide acted with KinC, an essential membrane-bound enzyme, and activated the expression of the genes needed for matrix production. The study concluded that biofilm formation is a response to the stress invoked by chlorine dioxide. Full study
Cluster of Carbapenemase-Producing Carbapenem-Resistant Pseudomonas aeruginosa Among Patients in an Adult Intensive Care Unit
MEGAN E. CAHILL, MARTHA JAWORSKI, VICTORIA HARCY, ERIN YOUNG, D. CAL HAM, PAIGE GABLE, KRIS K. CARTERCDC, MORBIDITY AND MORTALITY WEEKLY REPORT, AUGUST 2023 IntroductionThe report discusses an examination into the infections of carbapenemase-producing carbapenem-resistant Pseudomonas aeruginosa (CP-CRPA) in an Idaho hospital (Hospital A) between September 2021 and January 2022. The infections present a significant challenge due to the high antibiotic resistance and their ability to spread from person-to-person and via environmental sources. The study focuses on two patients from the same intensive care unit room, with both isolates characterized by specific carbapenemase gene type and multilocus sequence type. ResultsThe investigative team focused on the plumbing in the ICU room because Pseudomonas aeruginosa is known to persist in biofilm, a collection of microorganisms that adhere to one another and to a surface, such as a pipe. Water samples and swabs from two sinks and one toilet were collected. CP-CRPA with the same gene type isolated in the patients was found in one of the sinks, including swab samples from the drain, p-trap (a bend in a sink drain that holds water to block sewer gases), and sink counter. Water samples from the same sink’s p-trap and a toilet also tested positive for a different strain of CP-CRPA. Due to the genetic link between the patient isolate and sink isolate, the investigative team concluded that the most likely source of the outbreak was the ICU room sink. ConclusionThe report concludes that as of December 2022, no further CP-CRPA had been reported by Hospital A, suggesting the preventative measures implemented were successful. The work highlights the importance of collaboration between healthcare facilities and public health agencies, especially in identification and response to CP-CRPA clusters in a healthcare setting. Such cooperation, alongside the implementation of robust sink hygiene interventions, is critical in controlling the spread of such resistant infections. Full report
Examining the Efficacy of Copper-Silver Ionization for Management of Legionella
MARK LECHEVALLIERAMERICAN WATER WORKS ASSOCIATION (AWWA), WATER SCIENCE, MARCH 2023 IntroductionThis review article examined more than 80 sources of literature and studies related to copper-silver ionization system efficacy, design, maintenance, and operations, and the impact water chemistry has on its performance. ResultsPrevious research indicates that copper-silver ionization is effective for Legionella control. Other key findings of this study include: ConclusionThe report concludes that using copper-silver ionization to control Legionella and other opportunistic pathogens is highly effective when the units are properly designed, maintained, and operated. Full study
Hospitalizations Due to Selected Infections Caused by Opportunistic Premise Plumbing Pathogens and Reported Drug Resistance in the United States Older Adult Population
ELENA N. NAUMOVA, ALEXANDER LISS, JYOTSNA S. JAGAI, IRMGARD BEHLAU, JEFFREY K. GRIFFITHSPALGRAVE MACMILLAN, JOURNAL OF PUBLIC HEALTH POLICY, SEPTEMBER 2016 IntroductionThe study explores the health implications of opportunistic premise plumbing pathogens (OPPP) in US drinking water, particularly focusing on vulnerable populations like the elderly. These pathogens have gained attention due to the Flint Water Crisis, which exposed unresolved social, environmental, and public health issues related to changes in water source and treatment procedures. The study aims to understand the impact of OPPP, such as Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa, and highlights the need for improved monitoring and prevention. ResultsAnalyzing 108,202 hospitalization records from 1991 to 2006, the study reveals significant findings about OPPP-related hospitalizations among the elderly. Legionella pneumophila resulted in 7,933 cases of Legionnaires’ disease. Pseudomonas aeruginosa and gram-negative anaerobes contributed to 544,643 hospitalizations. Among non-tuberculous mycobacteria (NTM), pulmonary infection caused by Mycobacterium avium-intracellulare totaled 71% of the 48,854 cases. Reported drug resistance was observed in 1.68% of Pseudomonas infections, 1.05% of NTM infections, and 0.6% of Legionnaires’ disease cases. Drug resistance led to a 32.8% increase in Medicare charges. The estimated cost of Pseudomonas infections was $8.8 billion USD over 15 years, with a per-case differential payment of $14,510 for resistant cases. ConclusionThe study highlights a substantial economic burden of OPPP-related hospitalizations in the elderly, with antibiotic resistance significantly impacting costs. There is an urgent need for enhanced identification, reporting, and prevention strategies for these pathogens in premise plumbing systems. The authors emphasize the importance of interdisciplinary collaboration and increased efforts in monitoring and regulatory measures to address the growing issue of OPPP infections. The study underscores the need for comprehensive research to mitigate the health risks posed by these pathogens in drinking water. Full study
Controlling Legionella in Hospital Drinking Water: An Evidence-Based Review of Disinfection Methods
YUSEN LIN, JANET E. STOUT, VICTOR YUCAMBRIDGE UNIVERSITY PRESS, INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY, FEBRUARY 2011 IntroductionThis study reviewed the efficacy of different disinfection methods for controlling Legionella in hospitals, including copper-silver ionization, chlorine dioxide, hyperchlorination, monochloramine, UV, point-of-use filtration, and superheat-and-flush. The four criteria each disinfection method must meet to validate efficacy include: ResultsA summary of findings for each disinfection method is included below. Copper-silver ionization– Only method validated by the four criteria– Easy installation and maintenance– Not impacted by higher temperatures– Residual levels are maintained for a prolonged period– Efficacy declines in pH greater than 8.5 Chlorine dioxide– Penetrates biofilm– Effective over a wide range of pH levels– Creates harmful byproducts– Difficult to maintain residual levels Monochloramine– Penetrates biofilm– Effective over a wide range of pH levels– Can cause anemia in dialysis patients– On-site generation can be complicated Hyperchlorination– Most expensive and unreliable of all methods– Causes corrosion– Does not penetrate biofilm– Introduces carcinogens into the water Point-of-use filtration– Effective against Legionella and Mycobacterium– Provides immediate protection making them a good option for outbreaks– Not cost-effective for long-term use UV– Non-chemical– Works best when installed on the incoming water supply– Does not provide systemic disinfection Superheat-and-flush– Effective in emergencies– Not effective for prolonged use– Limited to hot water lines ConclusionThere are several viable methods for controlling Legionella, but copper-silver ionization was the only method validated by the four criteria at the time of this study. The researchers concluded that “copper-silver ionization appears to be the best available technology today for controlling Legionella colonization in hospital water systems.” They suggested that rigorous maintenance plans, regular monitoring of ion concentrations, and frequent Legionella testing are necessary to ensure long-term success. Full report
Intermittent Use of Copper-Silver Ionization for Legionella Control in Water Distribution Systems: A Potential Option in Buildings Housing Individuals at Low Risk of Infection
ZEMING LIU, JANET E. STOUT, MARCIE BOLDIN, JOHN RUGH, WARREN F. DIVEN, VICTOR L. YUOXFORD ACADEMIC, CLINICAL INFECTIOUS DISEASES, JANUARY 1998 IntroductionThis study evaluated three healthcare facilities colonized with Legionella to determine if: ResultsThe Legionella positivity rate (percentage of test sites positive for Legionella) was significantly reduced for the two test buildings using copper-silver ionization. Both test buildings remained Legionella-free for six to eight weeks after deactivating the copper-silver ionization system. The researchers found high concentrations of copper in the biofilm and suggested this to be the reason that early recolonization of Legionella was prevented. ConclusionBecause copper-silver ionization provides a residual effect of preventing early recolonization of Legionella, it is possible to rotate one copper-silver unit between several buildings. The study explained that this method could be considered for facilities that house individuals at low risk for contracting Legionnaires’ disease. Full study
Experiences of the First 16 Hospitals Using Copper-Silver Ionization for Legionella Control: Implications for the Evaluation of Other Disinfection Modalities
JANET E. STOUT, VICTOR L. YUCAMBRIDGE UNIVERSITY PRESS, INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY, AUGUST 2003 IntroductionThis study examined 16 acute care hospitals using copper-silver ionization as a disinfection method. Surveys were deployed in 1995 and 2000 to gather information from each hospital. The 2000 survey was up to 11 years after installation for some hospitals. ResultsBefore installing a copper-silver ionization system, all 16 hospitals had reported cases of hospital-acquired Legionnaires’ disease. Seventy-five percent had tried other disinfection methods, including superheat-and-flush, ultraviolet light, and hyperchlorination. After installing a copper-silver ionization system, no cases of hospital-acquired Legionnaires’ disease were reported, and the Legionella positivity rate (percentage of test sites within the hospital positive for Legionella) was significantly reduced. The study found that the infection control practitioners rated the disinfection system as “excellent.” The engineers rated the operation and maintenance of the system as “average” (not easy, but also not difficult). ConclusionThe team behind this study developed a standardized, evidence-based approach to assist hospitals with evaluating different disinfection methods. The four criteria a disinfection method must meet include the following: At the time of this study, copper-silver ionization was the only disinfection modality to have fulfilled all four evaluation criteria. Full study
Controlled Evaluation of Copper-Silver Ionization in Eradicating Legionella pneumophila from a Hospital Water Distribution System
ZEMING LIU, JANET E. STOUT, LOU TEDESCO, MARCIA BOLDING, CHARLES HWANG, WARREN F. DIVEN, VICTOR L. YUTHE UNIVERSITY OF CHICAGO PRESS, THE JOURNAL OF INFECTIOUS DISEASES, APRIL 1994 IntroductionThis study evaluated the efficacy of copper-silver ionization in a hospital with active Legionella colonization after superheat-and-flush and hyperchlorination had proven ineffective. ResultsSix months after installation, the Legionella positivity rate (percentage of test sites within the building positive for Legionella) dropped significantly in the test building. The copper-silver ionization systems were turned off to assess the length of time before Legionella recolonization. The test building remained negative for two months, with only one of the 26 test sites showing Legionella after four months. The control building remained positive. ConclusionCopper-silver ionization successfully eliminated Legionella in the hospital’s water system. The advantages of copper-silver ionization include relatively low cost, straightforward installation, easy maintenance, nontoxic by-products, and the presence of a disinfecting residual. Full study
Control of Legionella Contamination and Risk of Corrosion in Hospital Water Networks Following Various Disinfection Procedures
ISABELLA MARCHESI, GRETA FERRANTI, ANTONELLA MANSI, ANNA M. MARCELLONI, ANNA R. PROIETTO, NAVNEET SAINI, PAOLA BORELLA, ANNALISA BARGELLINIAMERICAN SOCIETY FOR MICROBIOLOGY, APPLIED AND ENVIRONMENTAL BIOLOGY, MAY 2016 IntroductionThis study evaluated four disinfection methods for their efficacy in controlling Legionella and their corrosive effects on water pipes. The four methods included: ResultsLegionella controlOf the four disinfection methods analyzed, monochloramine had the lowest Legionella positivity rate (percentage of test sites positive for Legionella), followed by chlorine dioxide, hydrogen peroxide, and heat. None of the methods eliminated Legionella. The results from the lowest Legionella positivity rate (most effective) to the highest (least effective): CorrosionHydrogen peroxide and chlorine dioxide caused pitting on the pipe’s interior surface. Pitting is a type of corrosion that can lead to holes. Monochloramine and heat appeared to be less aggressive, with monochloramine exhibiting uniform corrosion with the rare formation of pitting. Heat showed corrosion similar to that observed on the untreated samples. ConclusionContinuous chemical disinfection is effective to an extent and is significantly more effective than using only heat, and each modality displayed different morphologies of corrosion. Full report
Controlling Legionella in Hospital Water Systems: Experience With the Superheat-and-Flush Method and Copper-Silver Ionization
JANET E. STOUT, YU-SEN E. LIN, ANGELLA M. GOETZ, ROBERT R. MUDERCAMBRIDGE UNIVERSITY PRESS, INFECTION CONTROL AND HOSPITAL EPIDEMIOLOGY, DECEMBER 1998 IntroductionThis study evaluated the efficacy of superheat-and-flush and copper-silver ionization for Legionella control in an acute care hospital. The hospital had been using the superheat-and-flush method for 13 years but was still experiencing incidences of Legionnaires’ disease. ResultsLegionnaires’ cases decreased once the copper-silver ionization system was installed, with no cases reported in the last year evaluated by the study (1997). The average number of Legionnaires’ cases from 1979 to 1996 are included below. ConclusionCopper-silver ionization was found to be more effective in controlling Legionella than superheat-and-flush. The study notes that hospitals must conduct routine Legionella testing and closely monitor ion concentrations for copper-silver ionization to remain effective. Full study
