Inactivation of Geobacillus stearothermophilus spores by alkaline hydrolysis applied to medical waste treatment.

Although alkaline hydrolysis treatment emerges as an alternative disinfection/sterilization method for medical waste, information on its effects on the inactivation of biological indicators is scarce. The effects of alkaline treatment on the resistance of Geobacillus stearothermophilus spores were investigated and the influence of temperature (80 °C, 100 °C and 110 °C) and NaOH concentration was evaluated. In addition, spore inactivation in the presence of animal tissues and discarded medical components, used as surrogate of medical waste, was also assessed. The effectiveness of the alkaline treatment was carried out by determination of survival curves and D-values. No significant differences were seen in D-values obtained at 80 °C and 100 °C for NaOH concentrations of 0.5 M and 0.75 M. The D-values obtained at 110 °C (2.3-0.5 min) were approximately 3 times lower than those at 100 °C (8.8-1.6 min). Independent of the presence of animal tissues and discarded medical components, 6 log10 reduction times varied between 66 and 5 min at 100 °C-0.1 M NaOH and 110 °C-1 M NaOH, respectively. The alkaline treatment may be used in future as a disinfection or sterilization alternative method for contaminated waste.

Stability of SARS-CoV-2 in cold-chain transportation environments and the efficacy of disinfection measures.

Background: Low temperature is conducive to the survival of COVID-19. Some studies suggest that cold-chain environment may prolong the survival of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and increase the risk of transmission. However, the effect of cold-chain environmental factors and packaging materials on SARS-CoV-2 stability remains unclear. Methods: This study aimed to reveal cold-chain environmental factors that preserve the stability of SARS-CoV-2 and further explore effective disinfection measures for SARS-CoV-2 in the cold-chain environment. The decay rate of SARS-CoV-2 pseudovirus in the cold-chain environment, on various types of packaging material surfaces, i.e., polyethylene plastic, stainless steel, Teflon and cardboard, and in frozen seawater was investigated. The influence of visible light (wavelength 450 nm-780 nm) and airflow on the stability of SARS-CoV-2 pseudovirus at -18°C was subsequently assessed. Results: Experimental data show that SARS-CoV-2 pseudovirus decayed more rapidly on porous cardboard surfaces than on nonporous surfaces, including polyethylene (PE) plastic, stainless steel, and Teflon. Compared with that at 25°C, the decay rate of SARS-CoV-2 pseudovirus was significantly lower at low temperatures. Seawater preserved viral stability both at -18°C and with repeated freeze-thaw cycles compared with that in deionized water. Visible light from light-emitting diode (LED) illumination and airflow at -18°C reduced SARS-CoV-2 pseudovirus stability. Conclusion: Our studies indicate that temperature and seawater in the cold chain are risk factors for SARS-CoV-2 transmission, and LED visible light irradiation and increased airflow may be used as disinfection measures for SARS-CoV-2 in the cold-chain environment.

Inactivation of antibiotic-resistant bacteria and antibiotic-resistance genes in wastewater streams: Current challenges and future perspectives.

The discovery of antibiotics, which was once regarded as a timely medical intervention now leaves a bitter aftertaste: antimicrobial resistance (AMR), due to the unregulated use of these compounds and the poor management receiving wastewaters before discharge into pristine environments or the recycling of such treated waters. Wastewater treatment plants (WWTPs) have been regarded a central sink for the mostly unmetabolized or partially metabolised antibiotics and is also pivotal to the incidence of antibiotic resistance bacteria (ARBs) and their resistance genes (ARGs), which consistently contribute to the global disease burden and deteriorating prophylaxis. In this regard, we highlighted WWTP-antibiotics consumption-ARBs-ARGs nexus, which might be critical to understanding the epidemiology of AMR and also guide the precise prevention and remediation of such occurrences. We also discovered the unsophistication of conventional WWTPs and treatment techniques for adequate treatment of antibiotics, ARBs and ARGs, due to their lack of compliance with environmental sustainability, then ultimately assessed the prospects of cold atmospheric plasma (CAP). Herein, we observed that CAP technologies not only has the capability to disinfect wastewater polluted with copious amounts of chemicals and biologicals, but also have a potential to augment bioelectricity generation, when integrated into bio electrochemical modules, which future WWTPs should be retrofitted to accommodate. Therefore, further research should be conducted to unveil more of the unknowns, which only a snippet has been highlighted in this study.

Cumulative health risk assessment of disinfection by-products in drinking water by different disinfection methods in typical regions of China.

Disinfection was essential to keep human healthy from microorganisms in drinking water. Meanwhile, disinfection by-products (DBPs) have been proved to be associated with some adverse health effects. The DBP levels were different in drinking water disinfected by different methods and may cause diverse health risks. However, studies in this field and systematic analysis about risk characteristics are limited. We estimated the health risks of DBPs exposure in drinking water through multi-pathways, and systematically analyzed the characteristics of different disinfection methods and influence factors of health risk of DBPs in China. Drinking water samples were collected and analyzed for DBPs from some representative water treatment plants in several typical regions in China. We adopted the additive method to estimate the health risks of DBPs exposure in drinking water through multi-pathways, and used descriptive and hierarchical analysis to understand their characteristics and influence factors. The concentrations of the six DBPs in drinking water ranged from 1.6 µg/L to 13.3 µg/L. The cumulative cancer risk of DBPs exposure through multi-pathways was 8.63 × 10-5. The total HI of DBPs exposure was 1.70 × 10-1. The health risks of DBPs in drinking water disinfected by chlorine dioxide and sodium hypochlorite were lower than by other disinfection methods. The health risk of DBPs in drinking water was dominated by risk through oral and inhalation route. The health risks in wet season were higher than that in dry season. There is no significant difference in health risk for males and females, but children experienced higher health risks than adults. Our study suggested the situation of that a large population experienced the high cancer risk of DBPs in drinking water in typical regions of China. It was suggested that potential higher risk should be concerned, and possible measures could be considered to decrease the health risks.

Comparison of disinfection effects of different disinfection methods for caps of three-porous polypropylene infusion bottles / 中国实用护理杂志

Objective@#To compare the disinfection effect of three-hole polypropylene infusion bottle stopper by central sterilization method and groove central sterilization method, and to explore the best method of three-hole polypropylene infusion bottle cap disinfection.@*Methods@#A total of 1 088 bottles of three-pore polypropylene infusion bottles from 10 hospitals in Panzhihua City and the surrounding areas of Chengdu were selected for disinfection, and the effects were compared by fluorescent powder tracing method and bacterial culture method respectively. The two methods were divided into two groups: bottle stopper Central Sterilization group and groove Central Sterilization group. Each nurse sterilized two groups of liquid.@*Results@#The total area of fluorescent powder residues after disinfection of 272 bottles of infusion bottles with different specifications M(P25, P75) was 0.26 (0, 2.51). The total area of fluorescent powder residues M(P25, P75) was 15 (8, 24). There were significant differences in the residual area of fluorescent powder between the two groups after liquid bottle disinfection (Z=-17.31, P<0.01). Thirty-four positive specimens of bacteria culture, 68 bacterial colonies and 158 bottles of infusion bottles were disinfected by central sterilization of 160 bottles. There were 15 positive samples and 30 colonies of bacteria cultured in the bottle disinfected by groove central disinfection method (χ2=2.773, P<0.05).@*Conclusion@#The groove center disinfection method is the best disinfection method for the bottle stopper of three-hole polypropylene infusion bottle.

Evaluation on surface cleanliness of personal digital assistant as well as cleaning and disinfection efficacy / 中国感染控制杂志

Objective To investigate the cleanliness status of personal digital assistant(PDA)surfaces, and observe the effect of disposable antiseptic wipes on the cleaning and disinfection of PDA surface.Methods From January to March 2016, 83 daily used handheld PDA in 50 clinical wards of a hospital were as control group, 83 PDA disinfected by disposable antiseptic wipes(CaviWipes)and used in the same environment of the ward at the same time were selected as the intervention group, cleanliness status of PDA surfaces of two groups were detected by adenosine triphosphate(ATP)bioluminescence assay.Results Taken a cut-off value≤100 RLU/100 cm2 as qualified standard of cleanliness, none of PDA in control group was qualified with ATP bioluminescence reading ranged from 189 to 3 379 RLU;after disinfection with CaviWipes, the qualified rate of intervention group was 90.4％(n=75), ATP detection value of PDA surface in all departments were significantly lower than control group(median:[18-28] RLU vs[290-339]RLU, all P＜0.05).Conclusion Microbial contamination on PDA used in hospital wards is common, antiseptic wipes containing quaternary ammonium salt can be used for cleaning and disinfecting surface of PDA.

Investigation on dental model sanitation status in medical institutions in Changning District of Shanghai / 上海预防医学

Objective To investigate the sanitation status of dental model in medical institutions in Changning District of Shanghai, and to provide evidence for strengthening the disinfection management. Methods 40 medical institutions in Changning District of Shanghai were investigated by field sampling and detection. Results 92.5% of the investigated medical institutions disinfected dental models.In 168 dental model samples, the qualification rate of sanitary quality was 88.1%, while exceeded number of bacteria was the major reason for the unqualified.Among all dental model disinfection methods including ultraviolet irradiation, disinfectant soaking, disinfectant spraying and ozone, ultraviolet irradiation was the most widely used and disinfectant soaking was with the best effect.The storage sites of disinfected dental models including filling room, pollution area of sterilization room and other locations.Dental models stored in the filling room were with the highest qualification rate. Conclusion The current dental model sanitation status in medical institutions in Changning District of Shanghai is relatively unsatisfactory;supervision and inspection administration need to be strengthened by health and family planning administrative departments.

Effect of improving disinfection methods for skin and bottle caps on the detection rate of coagulase negative staphylococcus from blood culture / 中国感染控制杂志

Objective To compare different disinfection methods for skin and bottle caps on the detection rate of coagulase negative staphylococcus(CNS)from blood culture,and provide basis for improving collection process and accuracy of blood culture.Methods Blood specimens from the neonatal department of a hospital between June 2012 and August 2014 were collected,blood specimens cultured between June 2012 and June 2013 were as control group (routine disinfection during blood collection process),and blood specimens cultured between August 2013 and Au-gust 2014 were as intervention group (improved disinfection method for skin and bottle caps),detection rates of CNS between two groups were compared.Results In control group,41 isolates of pathogens were isolated from 543 blood culture specimens,positive rate was 7.55%;in intervention group,21 isolates of pathogens were isolated from 853 blood culture specimens,positive rate was 2.46%.The detection rate of CNS in control group was 4.97%(n=27),12 (2.21 %)of which were methicillin-resistant coagulase-negative staphylococcus (MRCNS);the detec-tion rate of CNS in intervention group was 0.82%(n=7),6 (0.70%)of which were MRCNS.Difference in detec-tion rates of CNS and MRCNS between two groups were both statistically significant(χ2 =24.07,5.92,both P <0.05).Conclusion Improving disinfection methods for skin and caps of blood culture bottles during blood collection can decrease the detection rate of CNS.

A comparative study in bacteriological analysis between re-used and disposable oxygen humidification devices / 中国实用护理杂志

Objective To carry out bacteriological analysis between re-used and disposable oxygen humidification devices. Methods Reused oxygen equipment and disposable oxygen moisture bottles from 6 randomly selected elderly wards were collected, patients who used oxygen will be randomized into 3 groups, group A used cold water as the oxygen humidification liquid, group B used distilled water as humidification liquid, group C used AQUAPAK disposable oxygen humidification devices, sample taking in group A and group B happened on every Monday and Thursday before the replacement of sample moisture bottles, sample was taken in group C after the use of disposable oxygen humidification devices, according to "hospital disinfection health standards" (GB5982-1995)sampling method of disinfection liquid sample was taken and sent to test in the disinfectant laboratory. Results Of 61 samples in group A bacteria cartier rate was 81.97%, bacteria carrier rate of 71 samples in group B was 47.89%, of 52 samples in group C the carrier rate was 0. The comparing of bacterial contamination rate of three kinds of oxygen moisture bottles after using was statistically significant. Take group A, B for comparison, the average severity level of bacteria in group A is higher than group B. In group A, the level of the Gram-negative bacteria as well as Gram-positive bacteria colonization was higher than group B. Conclusions Whether use of cold water or distilled water, oxygen humidification liquids have different degrees of pollution. Currently there is no general criteria and norms in the context of sterilization of oxygen humidification, for patients on long-term oxygen using, to choose disposable oxygen humidification device to reduce the incidence of hospital infections is recommended.

Prevention and Control Measures of Intestinal Virus Hospital Infection / 中华医院感染学杂志

OBJECTIVE To explore prevention and control measures and disinfection methods of intestinal virus hospital infection.METHODS Based on the prevention and control of hand-foot-and-mouth disease(2009),the measures on the administration of hospital infection and disinfection techniqul were taken,under the guidance of the center for disease control.RESULTS The effective prevention and control in intestinal virus stopped the spread and cross-infection.CONCLUSIONS Countermeasures of intestinal virus diseases caused by toxic encephalitis are effective following HFMD hospital infection prevention and control measures.

Disinfection of Ventilator Circuits:A Comparison with Three Methods / 中华医院感染学杂志

OBJECTIVE To compare the effect with the three methods to disinfect the ventilator circuits.(METHODS) To disinfect the ventilator circuits,three methods were used:A,soaking with chlorine compoud(disinfectant);B:soaking with 0.5% peracetic acid;C,sterilizing with ethylene oxide.Samples were taken to(bacteria) culture before and after disifection in every three methods.Biological supervision and the amount of colony were also taken at the same time.RESULTS The results of bacteria culture pre-disinfection were all positive.The amount of bacteria of ventilator circuits was between 70 000-120 000CFU/cm~2.The eligible rate of biological(supervision) in method C was 100% and its positive rate of bacteria culture was 0%.The eligible rate of biological supervision in method A was 86.25% and its positive rate of bacteria culture was 16.25%.The eligible rate of(biological) supervision in method B was 90% and its positive rate of bacteria culture was 13.78%.It was significant when method C was compared with methods A and B and the value P was less than 0.01.CONCLUSIONS It is(serious) about the pollution in ventilator circuits.The soaking methods are apt to be effected by the factors of(environment) and manual operation.Therefore it could be(ineligible) and being polluted after disinfection.The method of sterilization is the best for disinfection.