Abstract:Objective To evaluate the fit status of respirators and influencing factors of fit status through quantitative fitting testing. Methods Departments with different respiratory infectious disease exposure risks in 6 hospitals of different levels and properties were selected by stratified sampling, that is, hospital staff with low risk (ge-neral ward), medium risk (such as emergency and respiratory outpatient), and high risk (fever clinic, nucleic acid sampling point as well as department of infection control), including doctors, nurses, medical technicians and servicers, arch and folding respirators of two brands were tested, quantitative tightness and fitness of respirators were tested by environmental aerosol condensation nuclear counter method. Results A total of 320 staffs were selected from 6 hospitals to conduct the testing, before the formal fit testing, through professional guidance, the overall passing rate of the quantitative tightness check was significantly improved from 27.50% to 57.73% compared with the self-adjustment of the tested personnel. The passing rates of the fit testing of different respirators were significantly different (χ²=561.51, P < 0.001), with the lowest of 0.94% and the highest of 84.06%. After quantitative fit testing, when carrying out fit testing for standard movements, passing rates of arch A, folding A, arch B and folding B respirators were 50.00%, 58.25%, 66.67% and 85.67% respectively. Passing rates began to drop mainly after the left and right head swing. Conclusion Fit testing is a favorable tool to ensure the efficacy of respiratory protection, fit testing data should be fully utilized to provide suitable respirators for the staff.

Abstract:Objective To evaluate the effect of different ventilation modes on the diffusion of person's cough droplet nuclei in the elevator under the background of coronavirus disease 2019 epidemic. Methods Based on the computational fluid dynamics (CFD) gas-solid two-phase flow, Realizable K-ε turbulence model and particle trajectory model were used to study the diffusion process of droplet nuclei generated by person's cough in the elevator within 10 seconds, airflow velocity variation, droplet nuclei diffusion characteristics and concentration distribution of three kinds of ventilation at elevator top (the rear, both sides and four corners ventilation) were compared, risk on person was analyzed. Results Within 10 seconds, the number of airflow velocity vortex gradually decreased under the condition of ventilation at the rear and both sides, while increased when ventilation was at the four corners; droplet nuclei moved with the airflow in an inverted "S" shape trajectory when ventilation was at the rear, droplet nuclei moved up and down with the airflow when ventilation was at both sides, droplet nuclei presented a "C" shape trajectory when ventilation was at four corner. After 10 seconds, the increase of ventilation could quickly reduce the droplet nuclei concentration by 90%. Conclusion The opposite side of the droplet releaser is the high-risk area of contacting with the bacteria-carrying droplet nuclei. Although four corner ventilation can quickly dilute the overall droplet nuclear concentration, risk of infection can be increased if there is droplet releaser who is at the oblique opposite. Ventilation site should also be considered when ventilation volume increases, so as to reduce the risk of personnel infection.

Abstract:Objective To evaluate the colonization of carbapenem-resistant Klebsiella pneumoniae (CRKP) in neo- nates in neonatal intensive care unit (NICU), and analyze the risk actors for development of clinical infection from colonization. Methods Neonates in NICU of a hospital from January 2017 to December 2018 were selected as the research object. Since January 2017, active screening of CRKP anal swab/pharyngeal swab was carried out once a week within 48 hours after admission and during hospitalization period, monitoring on CRKP infection was performed at the same time, data was analyzed with SPSS 23.0 statistical software. Results A total of 1 230 NICU neonates were actively screened, 110 neonates were CRKP positive, CRKP colonization rate was 8.9%, 8.1% (97/1 197) of which was intestinal colonization, which was significantly higher than that (5.2%, 49/945) of the upper respiratory tract, difference was significant (P=0.008). Gestational age, low birth weight and prolonged hospital stay were risk factors for CRKP colonization (all P < 0.001). Diversilab homology monitoring found that the probability of CRKP colonization developing into clinical infection was 19.1% (21/110). Mechanical ventilation (OR, 10.177[95%CI, 2.667-38.830], P=0.013), high assessment on neonatal nutritional risk (OR, 0.251[95%CI, 0.072-0.881], P=0.031) and high score for neonatal acute physiology-Ⅱ (SNAP-Ⅱ) (OR, 8.256[95%CI, 6.072-20.881], P=0.025) were independent risk factors for the development of CRKP clinical infection in CRKP-colonized neonates. Conclusion CRKP colonization increases the probability of CRKP infection in NICU neonates during hospitalization, neonates receiving mechanical ventilation, malnutrition and high SNAP-Ⅱ score should be paid attention, so as to reduce the occurrence of CRKP clinical infection.

Abstract:Objective Taking a typical pedestrian exit process in a subway station as an example, the impact of micro crowd movement in public places on infection process was explored. Methods Based on the social force mo- del, infection transmission of pedestrians in the process of leaving the station was simulated to verify the effectiveness of relevant prevention and control measures under the background of coronavirus 2019 epidemic. Results Under the studied parameter settings and assumptions, rational setting stair barriers can reduce the number of infected people by about 23%, increasing pedestrian distance can reduce the number of infected person by about 25%, and increa-sing pedestrian moving speed can reduce the number of infected person by about 50%. Conclusion Rational barrier facilities, large pedestrian distance and expected speed can reduce the number of infected person, but the increase of the total number of person leaving station will reduce the effectiveness of the measures.

Abstract:Objective To investigate and analyze distribution characteristics and antimicrobial resistance of pathogens of wound infection in patients with different burn areas, so as to provide reference for clinical rational use of antimicrobial agents. Methods Bacterial culture results of burn patients with wound infection treated in Beijing Jishuitan Hospital from 2015 to 2020 were investigated, according to the different ratio of burn area to total body surface area (TBSA), patients were divided into three groups: less than 10% TBSA, 10%-49% TBSA and ≥ 50% TBSA groups. Distribution characteristics of pathogens of wound infection under different burn areas were analyzed, minimum inhibitory concentration of antimicrobial agents against main pathogens was detected, antimicrobial resistance rates of bacteria in different burn area groups were compared by χ² test. Results A total of 456 strains of wound infection bacteria were isolated from burn patients, including 120 strains in burn area < 10% TBSA group, 135 strains in 10%-49% TBSA group and 201 strains in ≥ 50% TBSA group. Gram-negative bacteria accounted for 52.2% (238 strains), mainly Pseudomonas aeruginosa (104 strains, 22.8%), Acinetobacter baumannii (39 strains, 8.5%) and Klebsiella pneumoniae (27 strains, 5.9%); Gram-positive bacteria accounted for 47.8% (218 strains), mainly Staphylococcus epidermidis (50 strains, 11.0%) and Staphylococcus aureus (44 strains, 9.6%). Distribution and resistance rate of pathogens causing wound infection at different burn areas were different. When burn area < 10% TBSA, Staphylococcus aureus was the main pathogen; the main pathogen were Pseudomonas aeruginosa and Acinetobacter baumannii in 10%-49% group and ≥ 50% TBSA group. Antimicro-bial resistance rate of bacteria in ≥ 50% TBSA group increased, resistance rates of Pseudomonas aeruginosa to cephalosporins and carbapenems were 87.9% (58/66) and 93.9% (62/66) respectively; the isolated 25 strains of Acinetobacter baumannii were multidrug-resistant strains; isolation rate of methicillin-resistant Staphylococcus aureus (MRSA) was 100% (9/9), which was significantly higher than that of burn patients in < 10% TBSA group and 10%-49% TBSA group (χ²=6.836, P < 0.05). Conclusion Distribution of pathogens of wound infection in patients with different burn areas is different, when burn area < 10% and ≥ 10%, the main pathogens are Gram-positive bacteria and Gram-negative bacteria respectively, when burn area ≥ 50%, the proportion of bacterial resis-tance and multidrug-resistant organism increased obviously.

Abstract:Objective To explore an effective rinsing method for reusing ophthalmic surgical instruments under the special condition of "Health Express" without running water cleaning equipment. Methods The study was divided into two stages to explore the effect of different rinsing methods on the removal effect and cleaning quality of multi-enzyme detergents for surgical instruments. The cataract microsurgical instruments without contamination and si-mulated clinical surgical contamination were selected respectively. Group A, B, C, D, F and G were trial groups, surgical instruments were rinsed with non-running water under the condition of simulated "Health Express", rinsing methods of group A, B and C were "2 L/4 L/6 L water combined with brushing", group D was with "no rinsing", group F adopted the same rinsing method as group B, group G adding "0.5 L water combined with rinsing" on the basis of group B. Group E and H served as the control group, using running water to rinse surgical instruments in accordance with the guidelines. Evaluation of cleaning effect: protein residue detector was used to detect indirectly the residue of multi-enzyme detergent, and ATP bioluminescence detector was used to detect the cleaning quality of surgical instruments. Results The residual amount of multi-enzyme detergent in group B was (1.90±0.23) μg per 20 surgical instruments, difference between multi-enzyme detergent residue in group B and control group ([3.45±0.46] μg per 20 surgical instruments) was not significant (P=0.053). ATP biofluorescence detection result in group G was (9.46±1.50) RLU per surgical instrument, difference between ATP biofluorescence detection result in group G and control group ([11.60±1.44] RLU per instrument) was not significant (P=0.339). Conclusion Combined with the results of two-stage experiments, group G rinsing method is recommended for rinsing ophthalmic surgical instruments under the special condition of "Health Express" without running water cleaning equipment.

Abstract:Objective To evaluate the efficacy of refined supervision measures on standardizing medical waste management. Methods Five wards of a tertiary hospital were selected to implement refined supervision measures, including special training and checking on medical waste classification knowledge, pasting graphic signs, on-site inspecting classification as well as on-site feedback and guidance. The baseline survey period was from March to May 2019, intervention period was from November 2020 to January 2021, health care workers' knowledge on medical waste classification, classification accuracy as well as changes in weight of medical waste before and after intervention were compared. Results After the implementation of refined supervision measures, the qualified rate of check of health care workers in medical waste classification knowledge (>60 points) increased from 51.67% (62/120) before intervention to 89.41% (152/170) after intervention, difference was significant (P < 0.001); qualified rate of waste classification increased from 81.34% (763/938) before intervention to 95.94% (1 017/1 060) after intervention (P < 0.05); the weight of medical waste decreased significantly, from 9 540.22 kg before intervention to 6 663.03 kg after intervention (P < 0.001). Conclusion Refined supervision measures improve health care wor- kers' knowledge and classification accuracy of medical waste classification, effectively improve the efficacy of medical waste management, and further standardize medical waste management.

Abstract:Objective To study the effect of intensive intervention measures based on compliance monitoring on prevention and control of Acinetobacter baumannii (AB) infection in intensive care unit (ICU). Methods Inpatients and health care workers (HCWs) in the general ICU of a tertiary first-class hospital from January 2019 to December 2020 were selected as the research objects. Baseline survey was conducted from January to December 2019 (before intervention) to investigate the basic condition of AB infection and colonization in patients. Intensive prevention and control strategies for multidrug-resistant organism (MDRO) were implemented from January to December 2020 (after intervention). A multi-department collaborative management team was set up to monitor compliance to prevention and control measures. Compliance to prevention and control measures, antimicrobial use, incidence of healthcare-associated infection (HAI), and changes of drug resistance of AB were compared. Results After the intervention, HCWs' compliance to prevention and control measures improved, implementation rate of single room isolation increased from 15.52% before intervention to 27.71% after intervention, HCWs' compliance rate to hand hygiene, wearing gloves and wearing isolation gown as well as the clearance rate of fluorescent markers on the environmental surface all improved in varying degrees (all P < 0.001). After intervention, the utilization rate of antimicrobial agents was lower than that before intervention (74.24% vs 80.06%, P=0.002), DDDs of antimicrobial use density was lower than those before intervention. After intervention, HAI rate, constituent ratio of AB HAI, and incidence of carbapenem-resistant AB (CRAB) HAI in patients decreased, difference was statistically significant (all P < 0.05). The main pathogens isolated from patients before and after intervention were both AB, constituent ratio of isolated AB after intervention was lower than that before intervention (21.24% vs 30.77%, P < 0.05). Antimicrobial resistance rates of AB to imipenem and meropenem decreased from 76.32% and 74.34% before intervention to 60.58% and 58.39% after intervention respectively, resistance rate to tegacyclin decreased from 10.53% before intervention to 1.46% after intervention (both P < 0.05). Conclusion Intensive prevention and control measures based on compliance monitoring has a good effect on reducing HAI and resistance of AB in ICU.

Abstract:Objective To investigate the relationship between emm typing, regional and virulence gene distribution of group A Streptococcus (GAS) isolated from children with scarlet fever. Methods Specimens from children with scarlet fever in Beijing and Shanghai were collected for GAS isolation and identification, emm genotype and carrying status of 13 kinds of virulence genes (speA, speB, speC, speF, speG, speH, speI, speJ, speK, speL, speM, ssa and smeZ) were detected by polymerase chain reaction (PCR), relationship between distribution of virulence gene and region as well as emm genotype of GAS strains was analyzed. Results Among 114 GAS strains, 60 were emm1.0 and 54 were emm12.0; 52 strains were isolated from Beijing(31 strains were emm1.0 and 21 were emm12.0), and 62 strains were from Shanghai(29 were emm1.0 and 33 were emm12.0). The carrying rates of speA, speC, speG, speH, speI, speJ, speK, ssa and smeZ were 52.6%, 76.3%, 80.7%, 43.9%, 55.3%, 57.0%, 75.4%, 97.4%, and 93.0% respectively, carrying rates of speB and speF were both 98.2%, speL and speM genes were not found. There were significant difference in carrying rates of speA, speH, speI and speJ genes of emm1.0 and emm12.0 GAS strains in Beijing as well as speA, speH, speI, speJ and speK genes of emm1.0 and emm12.0 GAS in Shanghai (all P < 0.05). Carrying rates of speC, speH, speJ and speK of emm1.0 GAS strain, as well as carrying rates of speC, speH, speI, speJ and speK of emm12.0 strain between Beijing and Shanghai were all significant (all P < 0.05). Conclusion Distribution of virulence genes of GAS strains is different with emm genotyping and region.

Abstract:Objective To systematically evaluate the risk factors for post-operative pulmonary infection (PI) in elderly patients with esophageal cancer. Methods China National Knowledge Infrastructure (CNKI), Wanfang database, CBM, PubMed, EMbase, Web of Science, Cochrane, Mediline and EBSCO were searched, studies (including case-control study and cohort study) on risk factors for post-operative PI in elderly patients with esophageal cancer published from the establishment of the database to January 4, 2021 were collected for systematic evaluation. Results A total of 18 literatures were included, Meta-analysis showed that independent risk factors for post-operative PI in elderly patients with esophageal cancer were pre-operative smoking history (OR, 2.45[95%CI, 1.93-3.10]), chronic obstructive pulmonary disease (OR, 2.64[95%CI, 1.83-3.83]) and diabetes mellitus (OR, 3.06[95%CI, 2.20-4.24]) in case-control study as well as pre-operative smoking history (OR, 6.07[95%CI, 1.75-21.00]) and diabetes mellitus (OR, 3.26[95%CI, 1.78-5.97]) in cohort study, intra-operative recurrent laryngeal nerve injury (OR, 2.36[95%CI, 1.54-3.62]), operation time>4 hours (OR, 3.09[95%CI, 1.43-6.67]), operation time>3 hours (OR, 1.87[95%CI, 1.10-3.16]) and single lung ventilation (OR, 2.58[95%CI, 1.75-3.82]) in case-control study as well as intra-operative recurrent laryngeal nerve injury (OR, 3.34[95%CI, 2.01-5.55]) in cohort study (all P < 0.05). Descriptive analysis showed that low body mass index, old age and malnutrition were the risk factors of post-operative PI in elderly patients with esophageal cancer. Conclusion Smoking history, chronic obstructive pulmonary disease, diabetes mellitus, low body mass index, old age, malnutrition, recurrent laryngeal nerve injury, and single lung ventilation are independent risk factors for post-operative PI in elderly patients with esophageal cancer.

Abstract:Objective To explore the application efficacy of failure mode and effect analysis(FMEA)in reducing multidrug-resistant infection (MDRO) in intensive care unit (ICU). Methods A special improvement team with the participation of ICU, healthcare-associated infection (HAI) department and general affairs department was set up, through investigation on current situation and implementation of a series of improvement and intervention measures, non-compliance rate of MDRO prevention and control measures and the discovery rate of MDRO HAI before and after the implementation of FMEA were compared. Results The non-compliance rate of MDRO prevention and control measures decreased from 31.99% (111/347) before the implementation of project to 6.07% (44/725) after the implementation, the discovery rate of MDRO HAI decreased from 19.89 ‰ (95/4 776) before the implementation of the project to 9.73 ‰ (46/4 728) after the implementation, differences were both statistically significant (both P < 0.05). Conclusion Combined with the current situation, application of FMEA quality improvement tool can effectively reduce MDRO infection rate in ICU. However, due to the difference in specimen detection rate, further research on HAI rate cannot be carried out, the follow-up research will focus on the MDRO specimen detection rate of large specimens in China.

Abstract:Objective To improve the submission quality of clinical microbial specimens through applying comprehensive intervention measures. Methods Patients who used therapeutic antimicrobial agents in a hospital from September 2018 to August 2020 were investigated, comprehensive intervention measures were implemented from September 2019. Comprehensive intervention measures included signing responsibility agreement, work quality assessment and feedback, knowledge training, and information system control. Submission rates of microbial specimens, sterile specimens, respiratory tract specimens and blood culture specimens of inpatients before (September 2018 to August 2019) and after intervention (September 2019 to August 2020) were compared. Results A total of 40 335 inpatients who used therapeutic antimicrobial agents were investigated, including 21 441 before intervention and 18 894 after intervention. After the intervention, submission rates of microbial specimens before antimicrobial the-rapy, restrictive antimicrobial therapy, and special antimicrobial therapy were 65.20%, 67.36% and 99.02% respectively, which were higher than 63.64%, 64.68% and 91.27% before intervention (all P < 0.05). Submission rate of sterile specimens increased from 13.81% before intervention to 15.85% after intervention, submission rate of respiratory specimens decreased from 37.63% before intervention to 35.68% after intervention (both P < 0.001). The proportion of sterile specimens increased from 30.43% before intervention to 34.84% after intervention, proportion of respiratory specimens decreased from 45.74% before intervention to 40.09% after intervention. The proportion of two or more sets of blood culture specimens increased from 18.63% before intervention to 21.95% after intervention (P < 0.001). Conclusion Application of comprehensive intervention measures can improve the submission rate and quality of clinical microbial specimens at the same time.

Abstract:Objective To evaluate the detection efficiency of different sampling methods to detect bacterial contamination on the surface of different materials, and explore a sampling method that not only conforms to national standards, but also can simply, quickly and accurately reflect the actual microbial contamination on object surface. Methods Surface of sterilized stainless steel plate and sterilized non-woven fabric were evenly coated with Staphylococcus saprophyticus, after natural drying, object surface were taken samples and detected the total number of bacterial colonies by adenosine triphosphate (ATP) bioluminescence assay, cotton swab smearing method, carrier imprinting method, and membrane filtration method, differences in different sampling methods were compared. Data were analyzed by SPSS 18.0 software. Results Under different contamination concentrations, stainless steel plates and non-woven fabrics had the highest number of bacteria detected by carrier imprinting method, followed by membrane filtration method, while cotton swab smearing method had the lowest number of detected bacteria. When bacterial colonies of non-woven fabric was 10⁶ CFU/mL, the qualified rate of carrier imprinting method (30.0%) was lower than that of cotton swab smearing method (80.0%), membrane filtration method (80.0%) and ATP bioluminescence assay (90.0%), differences were all statistically significant (all P < 0.05). ATP bioluminescence assay was prone to get false negative results. When bacterial concentration was 10⁷ CFU/mL, Pearson correlation coefficient between cotton swab smearing method and ATP bioluminescence assay was 0.838 (P=0.002), detection results of two sampling methods had good correlation. Conclusion Carrier imprinting method is more sensitive than cotton swab smearing method, membrane filtration method and ATP bioluminescence assay for the detection of bacterial colonies contaminated on object surface, carrier imprinting method can be used for the monitoring of bacteria on environmental object surface and hands in medical institutions; ATP bioluminescence assay and cotton swab smearing method have a good correlation to the detection results of bacterial load on artificially contaminated non-woven fabric surface.

Abstract:The symptoms of Strongyloides stercoralis infection are mild and difficult to be found in the early stage, which is prone to result in missed diagnosis and misdiagnosis, and cause severe complications even death if not treated in time. One patient had recurrent gastrointestinal symptoms, effect was poor after symptomatic treatment, during admission examination, it was found that there was co-infection of Strongyloides stercoralis and Clonorchis sinensis. This paper reports about this case as well as literature review, aiming to deepen the understan-ding of characteristics of Strongyloides stercoralis infection, provide more basis for clinical diagnosis and treatment.

Abstract:Community-acquired bacterial meningitis is still a worldwide infectious disease with high morbidity and mortality, it is also a disease that needs urgent treatment. Early and correct diagnosis, timely treatment and early prevention are the key factors to reduce morbidity of bacterial meningitis. This paper reviews the main pathogens, epidemiology and occurrence mechanism of bacterial meningitis as well as the current situation of diagnosis, treatment and prevention of this disease, so as to provide reference for further understanding of the occurrence, development, prevention, control and treatment of bacterial meningitis.

Abstract:Innate immune system is the first line of defense for microorganisms to invade the host, which is very important for the survival and health of human body. Antimicrobial peptide (AMP) is one of the important component of human innate immunity. LL-37 is the only AMP of the Cathelicidins family in humans, it is an amphiphilic helical peptide composed of 37 amino acid residues and has been proven to have broad-spectrum antimicrobial activity. This article focuses on summarizing the antimicrobial and immunomodulatory activities of LL-37, as well as the research progress of bacterial and fungal resistance to it.