Objective To study the antibacterial performance of a copper-based nanomaterial and the factors affecting its antibacterial effect, and to explore the the possibility of its practical application. Methods The film pasting method was used to test the antibacterial performance of the copper-based nanomaterial against Staphylococcus aureus and Escherichia coli, and the effects of organic interference, temperature and humidity changes, chemical neutralization and other conditions on the antibacterial performance of the material were studied. Results The killing logarithmic values of Staphylococcus aureus and Escherichia coli on the surface of the copper-based nanomaterial were >6.71 and >6.37 respectively when the nanomaterial was treated at 37℃ and a relative humidity of 90% humidity for 1 h. Using Staphylococcus aureus as the indicator bacterium, the killing logarithmic value decreased to 5.87 when 3% BSA was added; under the conditions of reducing temperature 20℃，90% and humidity 37℃，30%, the killing logarithmic values decreased to 2.78 and 3.59, respectively; after using D/E neutralizer, the killing logarithmic value decreased to 4.15.Conclusion This copper-based nanomaterial has good antibacterial performance, but organic interference and changes in environmental temperature and humidity can affect its bactericidal effect, and the use of neutralizers during evaluation will also directly affect the test results.

Objective To observe the germicidal efficacy of the disinfectant produced by a hypobromous acid generator and to explore the feasibility of its application. Methods Physicochemical analysis method and suspension quantitative germicidal test were used to observe the properties and germicidal efficacy of the bromine-containing disinfectant. Results Under the set conditions, the generator could produce disinfectant containing about 1 300 mg/L of available bromine. Staphylococcus aureus and Escherichia coli in suspension were exposed to the disinfectant containing 100 mg/L of available bromine for 5 min, and the killing log values were all >5.00; Pseudomonas aeruginosa and Candida albicans were exposed to the disinfectant containing 200 mg/L of available bromine for 5 min, and the average killing log value of Pseudomonas aeruginosa was >5.00 and the average killing log value of Candida albicans was >4.00; The spores of Bacillus subtilis var niger were treated with the disinfectant containing 500 mg/L of available bromine for 15 min, and the average killing log value was >5.00. The polioviruses were treated with the disinfectant containing 500 mg/L of available bromine for 10 min, and the average killing log value was >4.00. The metal pieces were soaked in the disinfectant containing 500 mg/L of available bromine for 72 h, there was slight corrosion for stainless steel, copper and aluminum, and moderate corrosion for carbon steel. Conclusion The disinfectant has good germicidal efficacy to the bacterial propagules, fungi, bacterial spores and poliovirus.

Objective To explore the feasibility of using phage Phi-X174 as indicator virus for evaluating the effect of air virus disinfection. Methods Phage Phi-X174 was nebulised into the air disinfection chamber. Referring to the requirements for the microbial counts of air indicators in China's air disinfection effect evaluation standards, the key parameters such as sampling solution, phage suspension titre, nebulisation time, nebulisation volume, etc were investigated to determine the generation mode and sampling method of phage aerosols, and the natural settling rates of phage aerosols at different time points were analyzed. Using the preliminarily established method, the killing effect of a photocatalytic disinfection technology on phage in air was evaluated. Results SM buffer was more efficient than PBS for phage Phi-X174 collection. When 1.5 mL of phage suspension with a titre of 3×10⁸ pfu/mL was nebulized, the average phage concentration in the air disinfection chamber was 4.25×10⁶ pfu/m³ with good reproducibility. The average natural settling rates of phage aerosols at 15 min, 30 min, 45 min and 60 min were 28.40%, 51.79%, 68.61% and 79.58%, respectively. The photocatalytic air disinfection technology was applied with high airflow for 45 min or low airflow for 60 min, and the average killing rate of phage could reach 99.9%. Conclusion Aerosol sampling with SM buffer and 1.5 mL of phage suspension with a titre of 3×10⁸ pfu/mL as the nebulisation generating solution can achieve relatively stable concentration of phage aerosols in air for a certain period of time, with better test reproducibility, and higher sampling efficiency, etc., which is basically in line with the requirements of air indicator microorganisms.

Objective To compare the survival time of human coronavirus HCoV-229E on different vectors of inanimate object surfaces, and to provide evidence for coronavirus disinfection. Methods Under the conditions of test ambient temperature of （25±1） ℃ and relative humidity of 55%±10%, the cell inoculation method was used to detect virus survival and the titer of virus suspension reached the national standard, and the survival test of HCoV-229E on different object surfaces was conducted. Results The virus titer on the vectors of paper and cloth decreased rapidly, and was close to 0 after 72 h of instilled contamination of paper and cloth. The virus titer decreased slowly on the plastic vector, and was 0.75 logTCID₅₀/0.1 mL after 5 d. The virus titer on the vectors of stainless steel and glass sheet decreased slowly, and was 1.0 logTCID₅₀/0.1 mL and 0.75 logTCID₅₀/0.1 mL respectively after 4 days, and no live virus was detected on all vectors of inanimate object surfaces after 5 d. Conclusion The survival times of HCoV-229E on different inanimate object surfaces are different, and targeted disinfection of object surfaces and environment should be carried out in actual disinfection work to improve disinfection efficiency.

Objective To evaluate the long-acting disinfection effect of polyhexamethylene biguanide hydrochloride disinfectant, and to provide a reference basis for the establishment of evaluation method for the long-acting disinfection effect of disinfectants in China. Methods Referring to the evaluation method of British standard PAS 2424, the killing effect of disinfectant samples with different concentrations on bacterial propagules and pathogenic yeasts was observed. Results This disinfectant sample had the best long-acting disinfection effect on Escherichia coli, followed by the long-acting disinfection effect on Staphylococcus aureus and Pseudomonas aeruginosa, and the worst long-acting disinfection effect on Candida albicans, and the difference was statistically significant (P<0.05).Conclusion The polyhexamethylene biguanide hydrochloride disinfectant sample has a 24 h long-acting disinfection effect on Escherichia coli and Staphylococcus aureus.

Objective To study the disinfection effect of a plasma air disinfection machine on indoor air under occupied (dynamic) and unmanned (static) conditions. Methods A plasma air disinfection machine was used in a kindergarten classroom to disinfect indoor air under occupied and unmanned conditions, and the planktonic bacteria, settling bacteria, particles and microorganisms load in indoor air before and after disinfection were compared to comprehensively assess the disinfection effect of the plasma. Results In unmanned room, the extinction rate of indoor air was more than 90% after 60 min of disinfection; in occupied room, the extinction rate of indoor air was still more than 50% despite continuous air pollution due to human activities. Regardless of whether there were people indoors or not, the settling bacteria, particles and microorganisms load in air were decreased after disinfection. Conclusion The plasma air disinfection machine can effectively eliminated bacteria and particles in air, and can be used in occupied room. It provides an effective disinfection method for preventing the indoor spread of airborne diseases.

Objective To investigate the clinical distribution and drug resistance of Citrobacter in nosocomial infection. Methods VITEK 2 automatic microbiological analyzer and GNI and GNS-13 were used to identify Citrobacter isolated from January 2013 to December 2022 and to conduct drug susceptibility tests. The results were analyzed using WHONET5.6 software. Results A total of 154 strains of Citrobacter were isolated, mainly from urine samples (53.25%), followed by pus/incision (16.88%). Among them, Citrobacter freundii was the most, accounting for 49.35%, followed by Citrobacter kirschi, accounting for 33.12%. The resistance rate of Citrobacter to cefazolin ranged from 97.8% to 100%, and the resistance rate to carbapenems was 0.0%. The resistance rate to third-generation or fourth-generation cephalosporins, cefotetan, aztreonam, gentamicin, tobramycin and quinolones were all less than 15.8%, and the resistance rate to piperacillin/tazobactam and nitrofurantoin were less than 1.7%. The resistance rate to co-trimoxazole was between 11.8% and 40.8%. Conclusion The drug resistance mechanism of Citrobacter is complex, and clinical practice should be guided by drug susceptibility results. Piperacillin/tazobactam and nitrofurantoin could be used as the first-choice drugs.

Objective To explore the application effect of fluorescent labeling method and microbiological method in evaluating the quality of cleaning and disinfection of the surrounding environment of patients with multidrug-resistant organism infection/colonization in intensive care units (ICU).Methods Focusing on the surrounding environment of all patients with carbapenem-resistantAcinetobacter baumannii infection/colonization in 12 ICUs in the hospital, fluorescent labeling methods and microbiological methods were used to compare the fluorescent labeling clearance rate, the qualified rate of microbial specimens and the detection rate of Acinetobacter baumannii of each ICU before and after the implementation of environmental cleaning intervention measures.Results After the intervention, the fluorescence labeling clearance rate increased from 35.85% to 66.94%, and the qualified rate of microbial specimens increased from 80.57% to 93.13%. The detection rate of Acinetobacter baumannii decreased from 27.43% to 8.75%, and the differences were all statistically significant (P<0.05). Conclusion Fluorescent labeling method and microbiological method can be used to evaluate the effect of object surface cleaning and disinfection in patients with multidrug-resistant organism infection/colonization.

Objective To investigate the prognostic factors of carbapenem resistant Enterobacteriaceae (CRE) infection in hospitalized patients. Methods Through pathogen specimen isolation and identification and antimicrobial susceptibility testing, the prognostic risk factors of hospital acquired CRE infection among hospitalized patients in a hospital were statistically analyzed. Results A total of 135 patients with CRE infection were investigated and analyzed. CRE was mainly isolated from lower respiratory tract secretions, accounting for 57.04%. The resistance rate of clinically isolated CRE strains to cephalosporin antibiotics exceeded 70%, and the resistance rate to ampicillin sulbactam and tobramycin reached 50% to 80%. Multivariate analysis showed that factors such as platelet count, bilirubin levels, complicated with cardiovascular and cerebrovascular diseases，multiple organ dysfunction syndrome, and gastric tube intubation were independent prognostic risk factors for patients with CRE infection. Conclusion The main site of CRE infection is the lower respiratory tract in this hospital, and the risk factors affecting patient prognosis are clear. Targeted prevention and control measures should be developed.

Objective To compare the survey results of two methods of nosocomial infection prevalence survey, and to provide a reference for further improving the prevalence survey method. Methods All hospitalized patients in a hospital on November 28, 2018 were selected as the research subjects, and the results of two methods for nosocomial infection prevalence survey were compared to determine a better prevalence survey method. Results This survey included 2 239 hospitalized patients. The prevalence rates of nosocomial infection obtained from traditional manual survey and information-based survey were 3.22% and 2.90%, respectively. The results obtained by traditional manual survey and information-based survey were basically the same. The specificity, total coincidence rate, positive predictive value, and positive likelihood ratio of information-based survey were all higher than those of traditional manual survey. Conclusion The prevalence survey is mainly based on information-based survey, and the quality control through manual survey is helpful to further improve the level of hospital infection surveillance.

Objective To understand the disinfection effect of environmental hygiene in Luoyang Central Hospital to provide a basis for strengthening nosocomial infection prevention and control. Methods Quantitative bacterial detection method was used to monitor and analyze the disinfection effect of Luoyang Central Hospital for five consecutive years. Results A total of 1 239 samples were collected from 2018 to 2022, with a qualified rate of disinfection effect of 89.67%. The qualified rate of dialysis water was the highest, while Class I environmental air was the lowest. The qualified rates of disinfection effect for five consecutive years from 2018 to 2022 were 88.66%, 90.00%, 86.94%, 93.38%, and 89.05%, respectively. Conclusion The hospital needs to strengthen the disinfection management of weak links in environmental air, hand hygiene of medical staff, and oral water.

Objective To understand the full-time personnel allocation of nosocomial infection management in medical institutions in Fuyang City, and to provide reference for strengthening the construction of nosocomial infection management teams. Methods A questionnaire survey was conducted to investigate the full-time personnel allocation of nosocomial infection in various levels of medical institutions in Fuyang City, Anhui Province. Results A total of 149 medical institutions were investigated in the city, including 10 tertiary institutions, 43 secondary institutions and 96 primary institutions. Specialized nosocomial infection management departments were set up in all tertiary medical institutions in the city, while the secondary and primary medical institutions with independent hospital infection management departments accounted for 81.40% and 37.50%, respectively. 81 medical institutions with specialized nosocomial infection management departments were equipped with 161 full-time personnel, and the control rate of full-time personnel ratio was only 25.93%. Conclusion The nosocomial infection management organization in primary medical institutions in this city is unsound. The standard allocation rate of full-time personnel is low, and the infection management organization needs to be improved.

Objective To understand the distribution of pathogenic bacteria in neonatal purulent meningitis and to provide reference for effective prevention and control. Methods Pathogenic specimen detection method was used to detect and analyze the pathogen specimens of children with purulent meningitis admitted to the neonatal intensive care unit (NICU) of a hospital. Results A total of 130 cases of early-onset and late-onset neonatal purulent meningitis were diagnosed in this survey. From the pathogenic specimens submitted by confirmed neonatal patients, 110 pathogens were detected, including 17 types of bacteria, and the proportion of Gram-positive and Gram-negative bacteria was equivalent. Among the 110 positive specimens, 54 were early-onset cases and 56 were late-onset cases. The top 5 pathogens were Escherichia coli, Streptococcus agalactiae, Klebsiella pneumoniae, Listeria monocytogenes, and coagulase negative Staphylococcus. Conclusions The pathogens of neonatal meningitis admitted to NICU in this hospital contain both Gram-positive and Gram-negative bacteria, and targeted prevention and control measures should be strengthened.

Objective To investigate the contamination status of Staphylococcus aureus on public elevator buttons of hospitals and hotels, and to observe the resistance of Staphylococcus aureus to commonly used disinfectants. Methods Baird-Parker screening medium was used to isolate Staphylococcus aureus, and the disinfectant resistance genes qacA/B, smr were amplified by polymerase chain reaction. The resistance of Staphylococcus aureus to commonly used disinfectants was tested using minimal inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC). Results A total of 21 strains of Staphylococcus aureus were detected on 83 public elevator buttons, with a detection rate of 25.3%. The detection rates of Staphylococcus aureus on the elevator buttons of hospitals and hotels were 10.0% and 39.5%, respectively, with a statistically significant difference (P=0.002). The genes qacA/B, smr were not detected in the 21 strains of Staphylococcus aureus isolated, but some strains showed higher resistance to quaternary ammonium disinfectants than the standard strains. Conclusion The contamination of hotel elevator buttons byStaphylococcus aureus is more severe than that of hospital elevator buttons, and it has been found that some Staphylococcus aureus had developed resistance to quaternary ammonium salt disinfectants.

Objective To understand multidrug-resistant organism (MDRO) infection and its risk factors in patients hospitalized in burn intensive care unit (ICU). Methods Retrospective study was used to investigate and analyze the etiological characteristics and risk factors of MDRO infection in the burn ICU of a hospital. Results A total of 139 inpatients were investigated, including 31 cases and 84 times of MDRO infection. The MDRO infection rate was 22.30% and the infection case rate was 60.43%. MDRO was dominated by Staphylococcus aureus and Acinetobacter baumannii, with constituent ratios of 45.24% and 28.57% respectively. MDROs were mainly separated from wound secretions and sputum, with the constituent ratios of 59.52% and 19.05% respectively. Multivariate analysis showed that ≥2 times of surgeries, central venous catheterization and urethral catheterization were independent risk factors for MDRO infection. Conclusion MDRO infections in burn ICU are mainly caused by Staphylococcus aureus and Acinetobacter baumannii. The risk factors are clear and effective prevention and control measures should be proposed.