Objective To study the disinfection effectiveness and safety of 222 nm ultraviolet, and to provide scientific basis for its practical application. Methods The quantitative virus inactivation test, carrier quantitative germicidal test, cell safety of layered cell slices and disposable skin irritation test were used to evaluate the virucidal effect, germicidal effect and safety of 222 nm ultraviolet source. Results Under the condition of radiation dose of 15 mJ/cm2, the killing rate of 222 nm ultraviolet on Escherichia coli and Staphylococcus aureus on carriers was 99.52% and 99.97%, respectively, when the organic interfering substance was 0.3% BSA; and the killing rates of the above two types of bacteria were 85.05% and 99.49% respectively, when the organic interfering substance was 3% BSA. When the radiation dose was 30 mJ/cm2, the inactivation rate of 222 nm ultraviolet on H1N1 influenza A virus, enterovirus 71 and poliovirusⅠvaccine strains on the carriers was up to 99.9%. When irradiated with the same dose in the layered cell model, the survival rate of the upper and lower cells was about 70% and 80%, respectively. At a radiation dose of 479 mJ/cm2, no obvious irritation was observed when rabbits skin were irradiated with 222 nm ultraviolet for 48 h. Conclusion The 222 nm ultraviolet had good killing effect on bacterial propagules and viruses, and its penetration into the deep cells was limited without obvious skin irritation.
Objective To observe the corrosiveness of commonly used disinfectants on metal surfaces, so as to provide a reference for their standardized use. Methods The corrosion testing method was used to observe the corrosiveness of alcohols, chlorine-containing disinfectants, hydrogen peroxide and quaternary ammonium salts on carbon steel, aluminum, copper, stainless steel and zinc. Results Alcohol disinfectants had no corrosion on stainless steel and copper, but had slight corrosion on zinc. Chlorine-containing disinfectant containing 1 000 mg/L effective chlorine had no corrosion on stainless steel, and had moderate corrosion on copper, aluminum and carbon steel. 60 g/L hydrogen peroxide disinfectant had no corrosion on stainless steel and carbon steel, moderate corrosion on zinc sheet and mild corrosion on aluminum. 1 000 mg/L quaternary ammonium salt disinfectants had no corrosion on stainless steel and copper, and light and moderate corrosion on carbon steel. Conclusion Except stainless steel, the four commonly used disinfectants have different degrees of corrosion on other four metals, among which alcohol and quaternary ammonium salt disinfectants are less corrosive.
Objective To evaluate the disinfection effect and mobility performance of an intelligent disinfection robot equipped with krypton chloride excimer photoelectric technology. Methods Laboratory disinfection tests and field applications were conducted to measure the ultraviolet irradiance of the equipment and its disinfection effect on Staphylococcus aureus contaminated stainless steel carriers. Mobility performance was assessed in a large sports venue. Results The intelligent disinfection robot consists of an excimer disinfection unit (rated power 100 W and 65 W, emitting 222 nm ultraviolet) and an autonomous robotic platform. Laboratory tests demonstrated a 99.99% average elimination rate of S. aureus on vertically placed stainless steel carriers (100 cm distance) after 10 min of irradiation. In field applications, the robot utilized LIDAR and navigation modules to achieve autonomous operation, patrolling, and obstacle avoidance. For areas≤10 m2, it automatically activated disinfection mode (30 min cycle) or standby based on human presence detection. For areas >10 m2, it performed autonomous path planning, multi-point disinfection, and auto-return functions at 0.1 m/s velocity, completing 60 m2 venue disinfection in approximately 25 min. Conclusion The intelligent disinfection robot exhibited excellent disinfection capability by using 222 nm ultraviolet radiation and demonstrated reliable autonomous navigation with static/dynamic obstacle recognition and avoidance capacities.
Objective To establish the quantitative test method for residual hydrogen peroxide on the surface of objects after vaporized hydrogen peroxide disinfection, so as to guide the safe treatment after disinfection. Methods The concentration of residual hydrogen peroxide on the surface of objects in the environment after vaporization hydrogen peroxide disinfection was determined by on-site sampling and ultraviolet spectrophotometry. Results The lowest detection levels were 1.051 3 μg, 1.062 4 μg and 0.078 4 μg for wipe-type, dip-type and fill-type consumables respectively, with the recoveries ranging from 85% to 120% and precision less than 15%. After normal sterilization in the isolator, inside the breathing bag, hydrogen peroxide residues were measured on vials, ordinary rubber stoppers and compartments of the sample package. Fluorine-coated stoppers were less likely to absorb hydrogen peroxide residues than ordinary stoppers. Conclusion The method is able to quantify hydrogen peroxide residues on sterilized consumables and countertops in isolators.
Objective To evaluate the disinfection effect and safety performance of a composite air disinfection machine integrating ultraviolet (UV) irradiation, photocatalytic technology, and medium-high efficiency filtration in enclosed confined spaces. Methods The device was assessed for UV irradiance, leakage levels of UV and ozone, and airflow rate. Simulated field air disinfection tests and actual elevator air disinfection trials were conducted to validate its effect against Staphylococcus albus aerosols and natural airborne bacteria. Results The air disinfector demonstrated an airflow rate of 247 m3/h, UV irradiance of 35 μW/cm2 with zero UV leakage, and an average ozone concentration of 0.05 mg/m3 after a 60 min operation. In the 20 m3 test chamber, >99.9% elimination of S. albus was achieved within 60 min. In 8 m3 elevator, >90.0% reduction of natural bacteria was observed after a 20 min operation. Conclusion The composite air sterilizer exhibits robust disinfection effect with minimal environmental hazards, making it suitable for enclosed confined space applications.
Objective To investigate dental unit waterline (DUWL) contamination in oral healthcare institutions of Yangzhou City, and to observe the intervention effects of disinfection methods. Methods Water samples of DUWL dental hand pieces, air/water syringes, mouth rinse units, and scaler outlets from 16 institutions were collected, and tested for bacterial contamination. Field disinfection experiments were conducted to observe the bacterial control effect of 25 and 50 mg/L chlorine dioxide disinfectant alone and in combination with multi-enzyme detergent on DUWL. Results A total of 175 dental water samples were collected, with an average total qualified rate of 54.29%. The qualified rate of different types of water samples varied significantly ( $\chi$2=10.968, P=0.027), which the highest qualified rate was washing water (80.00%) and the lowest was dental cleaning water (37.93%). The qualified rate of stomatology department in medical institutions was higher than that of private dental clinics ($\chi$2=6.642, P=0.010). On Day 1 after disinfection, qualified rates increased across all groups (P<0.05), though bacterial counts showed no significant intergroup differences (P>0.05). On Day 3, the qualified rates declined markedly, yet 50 mg/L chlorine dioxide combined with multi-enzyme detergent maintained efficacy in handpiece and syringe water (lower bacterial counts). For rinse/mouthwash units, all four methods showed comparable efficacy within one week (P>0.05). Conclusion The dental water exhibits moderate contamination in Yangzhou City, and the combination of chlorine dioxide and multi-enzyme detergent has a certain control effect on DUWL contamination.
Objective To explore the application value of sterilization parameter detection in the maintenance of pulsating vacuum pressure steam sterilizer. Methods The sterilization parameters were detected by the indicators and the temperature and pressure detector, and the indication function of these parameters in maintenance of the pulsating vacuum pressure steam sterilizer was observed and analyzed. Results Only one of the five pulsating vacuum pressure steam sterilizers passed the test, and four failed, including excessive balance time, maintenance time and temperature uniformity, as well as PCD and B-D test results. The balance time of one sterilizer was too long (147 s), the maintenance time was too short (65 s), and the monitoring results of type 6 PCD and B-D pack were unqualified. After several maintenance, the sterilization parameters were not up to standard. However, after the replacement of the inlet and exhaust solenoid valves, the sterilization parameters were significantly improved, the balance time was shortened (49 s), the maintenance time was extended (207 s), and the monitoring results of PCD and B-D packages were qualified. Conclusion The sterilization parameters can effectively determine the fault maintenance of the sterilizer, and can be used as the basis for judging the maintenance effect.
Objective To understand the status and training needs of air purification and disinfection in emergency departments of hospitals in Beijing. Methods A questionnaire survey was conducted to investigate the air purification and disinfection methods, usage of disinfection equipment in the emergency consultation rooms and waiting areas, observation and infusion areas, and rescue areas across 25 campuses of 22 municipal hospitals, as well as the training needs of medical staff regarding disinfection equipment. Results Regular air quality monitoring was implemented in 22 emergency departments, with natural ventilation, air conditioning system ventilation, and natural ventilation + air conditioning system ventilation predominating (each accounting for≥56.0%). Among 459 non-human-machine coexistence sterilizers (primarily UV lamps, >80.0% adoption), most UV lamps were used for terminal disinfection. All emergency departments with hydrogen peroxide sterilizer utilized them for terminal disinfection. 160 human-machine coexistence disinfectors (circulating air electrostatic / circulating air UV / plasma, <40.0% adoption) were rarely terminal-disinfected. Over 90.0% of emergency departments for non-human-machine coexistence disinfectors had protective measures, and most had dedicated operators, whereas human-machine coexistence disinfectors showed inadequate safeguards, and had lower dedicated operation rates for circulating air electrostatic/plasma disinfectors (55.6%, 66.7%). 42.9% of general hospitals prioritized operational training, while 72.7% of specialized hospitals requested theoretical training. Conclusion The air purification method in emergency departments is relatively perfect, but diversified disinfectors are required, and staff training on disinfection principles and operations should be enhanced.
Objective To identify the risks of nosocomial infection in the newly built hemodialysis centers of the healthcare consortium by applying the Failure Mode and Effects Analysis (FMEA) method, and to explore the effect of prevention, control, and mastery of the risk points. Methods FMEA was used to identify the risks of nosocomial infection in dialysis centers, and 38 potential risk points in 6 categories were quantitatively analyzed. The key risk points with the value of risk priority index (RPN) were identified, and improvement interventions were formulated and implemented, then the effect of the interventions were evaluated. Results The FMEA method was applied to find 10 risk points in 4 nosocomial infection risk categories, namely, unreasonable building layout and insufficient facilities, inadequate disinfection and maintenance of new equipments, non-compliance of personnel training and management, and incorrect sampling of surveillance specimens, with RPN values >125. After implementing the intervention measures, including adjusting the bed spacing in the isolation treatment area for infectious diseases, changing the location of the medical waste disposal room, standardizing the sampling process, and strengthening training, the RPN values of the 10 risk points were all <125. Conclusion FMEA helps to timely identify the risks of hospital-acquired infections in the newly built hemodialysis centers of the medical consortium. These risks are controlled after intervention.
Objective To understand the current status and disinfection quality of medical aesthetic institutions in Haidian District, Beijing in 2024, and to identify weak links for improvement. Methods On-site supervision, questionnaire survey and sampling inspection were carried out on 40 medical aesthetic institutions in the district, and the disinfection qualified rate of different monitoring projects was analyzed. Results All the units under investigation were not single-family buildings, and 7.5% of them had unreasonable layouts; 25.0% of them had laminar operating rooms. There were 64 disinfection personnel, of which 95.3% were part-time jobs, 28.1% were working for <3 years, and 53.1% were trained in urban and district-level professional knowledge. The disinfection qualified rates of medical aesthetic hospitals, medical aesthetic outpatient department, and medical aesthetic clinics were 94.27%, 97.07% and 94.52%, respectively, with no statistically significant difference ( $\chi$2=3.485, P=0.175). The sterilization and disinfection qualified rate of pressure steam sterilizer had the highest qualified rate (100.00%), the sterilization qualified rate of medical sewage disinfection was the lowest (40.00%), and the qualified rate of other projects was >95%. The qualified rates of Class Ⅱ, Ⅲ and Ⅳ ambient air disinfection were higher than that of ClassⅠenvironments ( $\chi$2=10.830, P<0.05). The qualified rate of disinfection of sewage with chlorine-containing disinfectants was lower than that of using ozone disinfection ( 22.72% vs 61.11%; $\chi$2=6.077, P<0.05). Conclusion The overall disinfection quality of medical aesthetic institutions in Haidian District is satisfactory. However, certain deficiencies persist. It is imperative to enhance professional knowledge training and technical guidance for disinfection personnel of medical aesthetic institutions, as well as reinforce regular oversight and monitoring of environmental air and medical sewage.
Objective To investigate the current status of disinfection quality of elderly care institutions in Qingdao, and to analyze the weak links, so as to provide technical guidance for the prevention and control of infectious diseases in elderly care institutions. Methods According to the Quality Monitoring Plan for Disinfection in Key Places in Qingdao, on-site investigations and sampling tests were conducted on the disinfection quality of 39 elderly care institutions from 2021 to 2023 in Qingdao, and the differences in qualification rates were compared. Results A total of 2 560 samples of different subjects were collected, and 2 287 were qualified, the total qualified rate was 89.34%. The highest qualified rate was 98.22% for tableware surfaces. The lowest qualified rate was 83.63% for staff hands. The qualified rates of disinfectant, indoor air and surface were 96.99%, 96.41% and 87.10%, respectively. The lowest qualified rate of hand hygiene among nursing staff was 75.86%. The qualified rate of monitoring in medical and elderly care institutions was higher than that in non medical and elderly care institutions (91.56% vs 87.62%； $\chi$2=10.258，P=0.001). Conclusion The disinfection quality of elderly care institutions in Qingdao is generally good. The qualified rates of some projects such as the surface of faucets and the hands of nursing staff are relatively low. It is necessary to strengthen disinfection training and guidance, as well as hygiene supervision, in response to weak links.
Objective To understand the disinfection quality of public medical institutions at various levels in Ningxia, so as to provide references for infection control in medical institutions. Method According to the GB15982—2012 Hospital Disinfection and Hygiene Standards, on-site sampling and detection of microbial indicators were conducted on 7 items including indoor air, object surfaces, and medical water in 66 medical institutions from 2021 to 2023, and the qualified rate of disinfection quality was analyzed and evaluated. Result A total of 17 656 monitoring samples were collected from public medical institutions at all levels in Ningxia, with a total qualified rate of 97.74%. The annual qualified rate was on the rise ( $\chi$2trend=9.592, P<0.001). There was a statistically significant difference in the qualified rate of medical institutions at different levels ( $\chi$2=93.221, P<0.001), with the overall qualified rate of first level medical institutions being the lowest (96.45%) and the qualified rate of second level medical institutions being the highest (98.84%). There was a statistically significant difference in the qualified rate of disinfection quality among different monitoring items ( $\chi$2=350.061, P<0.001), with the lowest qualified rate for medical water (90.52%) and the highest qualified rate for disinfectant in use (99.74%). The qualified rate of ultraviolet lamps and medical water increased year by year in the past three years ( $\chi$2trend= 9.863 and 7.170, P<0.05). Conclusion The overall disinfection quality of public medical institutions in Ningxia from 2021 to 2023 is relatively high, with a qualified rate of over 95%. However, the disinfection quality of first level medical institutions still needs to be improved. Endoscopes and medical water are weak links in disinfection work, and special monitoring should be further carried out.
Objective To investigate the status of disinfection and infection prevention and control management in funeral places, as well as the microbial contamination status, and to analyze the impact of IPC management on microbial contamination in funeral places. Methods By employing a questionnaire survey method, 19 funeral places were randomly selected from six provinces (municipalities) across the country to investigate the status of infection prevention and control as well as disinfection-related work. Simultaneously, on-site sampling and microbial testing were conducted to determine the total bacterial colony counts on surfaces of makeup and cosmetic tools, cremator buttons, and surfaces in contact with cadavers within these facilities. Furthermore, influencing factors of environmental microbial contamination were analyzed. Results The implementation rate of infection control knowledge training was relatively low (31.58%). The implementation rates of management measures in funeral places were relatively high for the following items: having established disinfection related regulations or protocols (68.42%), regularly inspecting the implementation of disinfection (63.16%), and strictly performing object surface disinfection according to the scope specified by the standards (57.89%). A total of 466 surface samples were collected on-site, among which 79.61% had a total bacterial colony count of ≤300 cfu/25 cm2. The qualification rates for surface samples in large, medium, and small funeral service facilities were 72.85%, 71.97%, and 92.40%, respectively, with small facilities showing a higher qualification rate ($\chi$2=25.385, P<0.05). Among various types of surface samples, faucets had the lowest qualification rate (48.57%), while cremator buttons had the highest rate (100.00%). The qualification rates for embalming equipment and door handles in makeup rooms were relatively low, at 56.00% and 64.29%, respectively. Conclusion The microbial contamination levels on surfaces of faucets and embalming instruments within funeral homes are relatively serious, and the implementation rate of comprehensive disinfection coverage on object surfaces should be improved.
Objective To understand the current situation of off-site law enforcement supervision of disinfection and sterilization in dental clinics in Jiangsu Province, and to analyze the existing problems. Methods The current situations of off-site enforcement of disinfection and sterilization monitoring in dental clinics in four pilot cities were investigated through interviews and questionnaires to analyze abnormal events and problems existing in disinfection and sterilization work. Results A total of 518 dental clinics were investigated, and the clinics that accepted off-site law enforcement for disinfection and sterilization in Changzhou, Nantong, Lianyungang and Yangzhou accounted for 82.50%, 29.80%, 21.30% and 7.50%, respectively. A total of 1 054 abnormal events and 358 abnormal complaints were reported in the four pilot cities, among which the sterilization time, sterilization pressure, sterilization temperature which was lower than the prescribed value and sterilization temperature error which exceeded 3℃ were 64.90%, 0.85%, 32.83% and 1.42%, respectively. The proportion of biological monitoring indental institutions was higher (90.2%), while the qualified rate of temperature parameter monitoring in private clinics was low, only 68.2%. Conclusion Off-site disinfection and sterilization law enforcement can help improve the efficiency of health supervision in dental clinics, which should be combined with key issues and key links to achieve efficient and accurate law enforcement.
