Inactivation of Spores and Vegetative Forms of Clostridioides Difficile by Chemical Biocides: Mechanisms of Biocidal Activity, Methods of Evaluation, and Environmental Aspects

Clostridioides difficile infections (CDIs) are the most common cause of acquired diseases in hospitalized patients. Effective surface disinfection, focused on the inactivation of the spores of this pathogen, is a decisive factor in reducing the number of nosocomial cases of CDI infections. An efficient disinfection procedure is the result of both the properties of the biocidal agent used and the technology of its implementation as well as a reliable, experimental methodology for assessing the activity of the biocidal active substance based on laboratory models that adequately represent real clinical conditions. This study reviews the state of knowledge regarding the properties and biochemical basis of the action mechanisms of sporicidal substances, with emphasis on chlorine dioxide (ClO2). Among the analyzed biocides, in addition to ClO2, active chlorine, hydrogen peroxide, peracetic acid, and glutaraldehyde were characterized. Due to the relatively high sporicidal effectiveness and effective control of bacterial biofilm, as well as safety in a health and environmental context, the use of ClO2 is an attractive alternative in the control of nosocomial infections of CD etiology. In terms of the methods of assessing the biocidal effectiveness, suspension and carrier standards are discussed.

Is The Disinfection Procedure of The Intensive Care Unit Able To Reduce the Bacterial Resistance and Risk of Contamination?

Background: Healthcare-associated infections (HAIs) represent one of the main causes for the morbidity and mortality in the intensive care unit (ICU). In this study, we aimed to verify the presence, type, and antimicrobial susceptibility of bacteria in ICU settings, before and after disinfection procedures, and analyze the risk of contamination related to these bacteria in each area of the ICU.Methods: The study was conducted in the ICU of a medium-sized hospital in Brazil from February 2019 to February 2020. Samples were obtained from the surfaces of beds, bathrooms, pantries, sinks, pharmacies, administrative areas, and floors, before and after the disinfection process, with 1% benzalkonium chloride and biguanide mixture (BCB). The samples were processed and inoculated in different culture media for the selective isolation of strains of clinical interest. In addition, phenotypic identification and antimicrobial susceptibility tests were performed using the VITEK® 2 system. We grouped different environmental, temporal, and microbial factors and characteristics to calculate the risk of contamination before disinfection (Rbd) and after disinfection (Rad), as well as the total risk (Rtt) and real risk observed (Foldrisk) in the ICU.Results: Gram-positive cocci and rods, gram-negative rods of the Enterobacteriaceae family, and non-fermenting gram-negative rods were recovered after disinfection and were found to be widely distributed. Higher bacterial diversity and frequency of resistance were observed, mainly the resistance of gram-positive bacteria to cephalosporin (p < 0.05) and lincosamides (p < 0.0001), and gram-negative bacteria to quinolones (p < 0.0001) and aminoglycosides (p < 0.05). The pantry, pharmacy, and beds showed major risks of contamination after disinfection (Rad), ranging from intermediate to very high-risk levels. Foldrisk for the pantry and beds presented a significant increase in two and three risk levels, respectively, after the disinfection process.Conclusions: Our results demonstrate the presence of bacterial pathogens with multidrug-resistant profiles after disinfection with a higher risk of contamination, indicating that challenges still exist in the deployed disinfection protocols in the ICU settings, which are associated with the increased critical risk of HAIs after the disinfection procedure.

Machine Learning-Mediated Development and Optimization of Disinfection Protocol and Scarification Method for Improved In Vitro Germination of Cannabis Seeds

In vitro seed germination is a useful tool for developing a variety of biotechnologies, but cannabis has presented some challenges in uniformity and germination time, presumably due to the disinfection procedure. Disinfection and subsequent growth are influenced by many factors, such as media pH, temperature, as well as the types and levels of contaminants and disinfectants, which contribute independently and dynamically to system complexity and nonlinearity. Hence, artificial intelligence models are well suited to model and optimize this dynamic system. The current study was aimed to evaluate the effect of different types and concentrations of disinfectants (sodium hypochlorite, hydrogen peroxide) and immersion times on contamination frequency using the generalized regression neural network (GRNN), a powerful artificial neural network (ANN). The GRNN model had high prediction performance (R2 > 0.91) in both training and testing. Moreover, a genetic algorithm (GA) was subjected to the GRNN to find the optimal type and level of disinfectants and immersion time to determine the best methods for contamination reduction. According to the optimization process, 4.6% sodium hypochlorite along with 0.008% hydrogen peroxide for 16.81 min would result in the best outcomes. The results of a validation experiment demonstrated that this protocol resulted in 0% contamination as predicted, but germination rates were low and sporadic. However, using this sterilization protocol in combination with the scarification of in vitro cannabis seed (seed tip removal) resulted in 0% contamination and 100% seed germination within one week.

Microbiological Monitoring of the Environment Using the “Association Rules” Approach and Disinfection Procedure Evaluation in a Hospital Center in Morocco

Background. The hospital environment, especially surfaces and medical devices, is a source of contamination for patients. Objective. This study carried out, to the best of our knowledge, for the first time at Taza Hospital in Morocco aimed to assess the microbiological quality of surfaces and medical devices in surgical departments and to evaluate the disinfection procedure in time and space. Methods. Samples were taken by swabbing after cleaning the hospital surface or medical device, to isolate and identify germs which were inoculated on semiselective culture media then identified by standard biochemical and physiological tests, using the analytical profile index (API) galleries. Moreover, the association rules extraction model between sites on the one hand and germs on the other hand was used for sampling. Results. The study showed that 83% of the samples have been contaminated after biocleaning. The most contaminated services have been men’s and women’s surgeries. 62% of isolated germs have been identified as Gram-positive bacteria, 29% as Gram-negative bacteria, and 9% as fungi. Concerning the association rules extraction model, a strong association between some contaminated sites and the presence of germ has been found, such as the association between wall and nightstand and door cuff, meaning that the wall and nightstand contamination is systematically linked to that of the door cuff. The disinfection procedure efficacy evaluation has enabled suggesting renewing it each 4 h. Conclusion. Microbiological monitoring of surfaces is necessary at hospital level through the use of the association rule extraction model, which is very important to optimize the sampling, cleaning, and disinfection site scenarios of the most contaminated ones.

Interaction between Biofilm Formation, Surface Material and Cleanability Considering Different Materials Used in Pig Facilities—An Overview

Sometimes the contamination in pig facilities can persist even after the washing and disinfection procedure. Some factors could influence this persistence, such as bacteria type, biofilm formation, material type and washing parameters. Therefore, this review summarizes how the type of surface can influence bacteria colonization and how the washing procedure can impact sanitary aspects, considering the different materials used in pig facilities. Studies have shown that biofilm formation on the surface of different materials is a complex system influenced by environmental conditions and the characteristics of each material’s surface and group of bacteria. These parameters, along with the washing parameters, are the main factors having an impact on the removal or persistence of biofilm in pig facilities even after the cleaning and disinfection processes. Some options are available for proper removal of biofilms, such as chemical treatments (i.e., detergent application), the use of hot water (which is indicated for some materials) and a longer washing time.

Microbiological Surveillance of Endoscopes in a Southern Italian Transplantation Hospital: A Retrospective Study from 2016 to 2019

Endoscopes are medical instruments that are used routinely in health structures. Due to their invasive nature and contact with many patients, they may cause hospital-acquired infections if not disinfected correctly. To ensure a high-level disinfection procedure or reprocessing, since the methods currently adopted in our institute are adequate, we evaluated retrospectively the presence of microorganisms in our endoscopes after reprocessing. Microbiological surveillance was performed from January 2016 to December 2019 in the instruments in use in our endoscopic room after reprocessing. In total, 35 endoscopes (3 duodenoscopes, 3 echoendoscopes, 12 bronchoscopes, 5 colonoscopes, and 12 gastroscopes) were evaluated for the presence of microorganisms, including multidrug-resistant pathogens and indicator microorganisms (IMOs). Our procedures were in agreement with an internal protocol based on Italian, international, and the Center for Disease Control and Prevention (CDC) recommendations. Of a total of 811 samples, 799 (98.5%) complied with the regulatory guidelines, while 9 (1.1%) were positive for IMOs, and 3 (0.4%) displayed more than 10 colony-forming units (CFU) of environmental and commensal pathogens. Our results show that the internal reprocessing protocol is very efficient, leading to a very low number of observed contaminations, and it could be easily implemented by other health facilities that face a huge number of hospital-acquired infections due to incorrectly disinfected endoscopes.

Hand Areas Which Are Commonly Missed during Hand Disinfection by Nursing Students Who Completed a Basic Educational Course in Hand Hygiene

Background: Teaching nursing students how to correctly perform hand hygiene procedures may guarantee a reduction in transmitting pathogens through direct contact and, thus, it may lead to a decrease in the number of hospital infections. The aim of the study, which was conducted in low fidelity simulation conditions, was to assess the performance and the efficiency of a hand-rubbing disinfection technique among nursing students on the last day of their course. Materials and methods: The study was conducted in a group of 190 nursing students studying at the Jagiellonian University and it focused on the performed hand-rubbing disinfection procedure. The accuracy of the task performance was assessed by measuring the percentage of the amount of Fluo-Rub (B. Braun) fluorescent alcohol-based gel remaining on students’ hands after disinfection. The gel was rubbed into particular hand parts including four surfaces (left palm, right palm, left back and right back) divided into thirteen areas (I–XIII) and each surface was examined separately. The results were then dichotomized based on the cut-off point of 10% and two categories: “clean” and “dirty” were established. Additionally, the range of negligence in the disinfection procedure was assessed by counting the total number of the areas classified as “dirty”. The comparison of continuous and categorical variables was conducted by means of Friedman’s and Cochrane’s tests, respectively. Results: It was found out that the palm surfaces that were commonly missed during hand disinfection included the whole thumb (I and VI), the fingertip of the little finger (V) and the midpalm (XIII), whereas in the case of back surfaces (on both right and left hand) the most commonly missed areas were the fingertips and the whole thumb I–VI. Only 30 students (13%) had all 52 areas of both hands completely clean, whereas more than one third—66 students (33%)—failed to disinfect properly more than 10 areas out of all assessed ones on the surfaces of both hands. Conclusions: In the examined group of nursing students, a significant lack of compliance with hand disinfection procedures was observed and it was related mainly to thumbs and back parts of both hands. Therefore, it is essential to conduct systematic training sessions and assessment of hand hygiene procedures for nursing students at the end of every educational stage as it can lead to their developing these skills properly.

Awareness, Attitude and Practice on Sterilization among Healthcare Staffs of a Tertiary Hospital in Bangladesh

The background and objective of this study are to assess the awareness, attitude, and practice on sterilization among health-care staffs of a tertiary hospital in Bangladesh. This cross-sectional study was done in a renowned hospital in Dhaka city, from July 03, 2020, to August 05, 2020. A stratified random sample survey was done. The total sample size was 73 health care staff, including the OT nursing staff, OT technicians, and CSSD (Central Sterile Supply Department) laboratory technicians, who were involved in sterilization and disinfection procedure. A questionnaire with both and open-ended questions was given among the respondents including socio-demographic close-ended variables, such as sex, age, working experience, job nature of the participants, and details regarding the ethical approach to attitude, awareness as well as the practice of sterilization and disinfection and its proper management, methods, and the knowledge regarding management of biomedical wastes. 79.5% of health care staff were aware of managing biomedical waste but 20.5% were not aware of it. Only 61.6% of healthcare staff wear PPE properly but 38.4% didn’t agree. The number of health care staff (20.5%) had not taken any vaccine against the Hepatitis B virus. 86.3% of healthcare staff had a positive attitude on biomedical waste management. 91.8% of staff had a positive attitude to a vaccination before performing disinfection and sterilization procedure. 82.2% positive attitudes were detected in wearing PPE before sterilization & disinfection procedure according to this study. This type of research also should be conducted in all government hospitals, medical college hospitals as well as all private hospitals to assess the current scenario & recommend for rectification where necessary.

Efficacy of Three Commercial Disinfectants in Reducing Microbial Surfaces’ Contaminations of Pharmaceuticals Hospital Facilities

To evaluate and validate the efficacy of disinfectants used in our cleaning procedure, in order to reduce pharmaceutical hospital surfaces’ contaminations, we tested the action of three commercial disinfectants on small representative samples of the surfaces present in our hospital cleanrooms. These samples (or coupons) were contaminated with selected microorganisms for the validation of the disinfectants. The coupons were sampled before and after disinfection and the microbial load was assessed to calculate the Log10 reduction index. Subsequently, we developed and validated a disinfection procedure on real surfaces inside the cleanrooms intentionally contaminated with microorganisms, using approximately 107–108 total colony forming units per coupon. Our results showed a bactericidal, fungicidal, and sporicidal efficacy coherent to the acceptance criteria suggested by United States Pharmacopeia 35 <1072>. The correct implementation of our cleaning and disinfection procedure, respecting stipulated concentrations and contact times, led to a reduction of at least 6 Log10 for all microorganisms used. The proposed disinfection procedure reduced the pharmaceutical hospital surfaces’ contaminations, limited the propagation of microorganisms in points adjacent to the disinfected area, and ensured high disinfection and safety levels for operators, patients, and treated surfaces.

Application of electromagnetic field energy in disinfection cabins for prevention and reduction of spread of viral infections

The article suggests the use of disinfectants (disinfection cabins) for prevention and reduction of the spread of viral infections (EMF energy is applied there which is harmful to coronavirus strain and harmless to the human body). The analysis of publications on the influence of the electromagnetic field on bacteria and viral infections is given. The physical nature of EMF energy is presented, which is based on estimation of EMF energy in the surrounding space using the Poynting vector. A device for creating the energy load of low-frequency EMF is proposed in order to consider its harmful effect on coronavirus strains. The possibility of using disinfection cabins along with alternative methods of disinfection of premises is shown. The proposed use of disinfection cabin in railway transport will allow for safe disinfection of personnel, clothing and materials during mandatory medical examinations of employees and ensure the safety of train traffic. With successful results of the use of disinfection cabins, the procedure can be used to disinfect passenger traffic. The authors consider practical methods and tools for prevention and reduction of the risks of spread of the new coronavirus infection COVID-19 in JSC «Russian Railways». It is worth mentioning that with alternative methods of disinfection, there is not always the possibility of a person being in the room, which significantly complicates the disinfection procedure and affects the result.