ObjectiveTo analyze the distribution, drug resistance characteristics, and changing trends of Acinetobacter baumannii (AB) isolated from environmental surfaces and healthcare workers’ hands in a grade Ⅱ level A general hospital in Xuhui District of Shanghai from 2018 to 2023, and to provide reference for infection control in the hospital. MethodsEnvironmental samples were collected quarterly from critical surfaces and healthcare workers’ hands in the intensive care unit (ICU), geriatrics, and respiratory departments from 2018 to 2023. Clinical isolates were obtained from all patients with AB infections in ICU, geriatrics, respiratory department, rehabilitation department, infectious diseases department, emergency department, cardiology department, and orthopedics of the hospital from 2018 to 2023. Retrospective analyses were performed on AB detection rates, strain origins, resistance rates to commonly used antimicrobial agents, and resistance gene features, comparing the antimicrobial resistance between clinically isolated strains and environmentally isolated strains. ResultsFrom 2018 to 2023, a total of 1 416 samples were collected from the hospital and a total of 272 strains of AB were detected, with a positive detection rate of 19.21%. The detection rate gradually decreased year-on-year (χ²_trend=45.290, P<0.001). The majority of samples originated from patient-contacted items (34.56%, 94/272), followed by shared items (26.84%, 73/272) and healthcare worker-contacted items (15.07%, 41/272). From 2018 to 2023, the resistance rate of AB on environmental surfaces and healthcare workers’ hands to commonly tested antibiotics in the hospital ranged from 10% to 40%. The resistance rates to cefotaxime (42.52%) and piperacillin (38.58%) were relative high, while the resistance to polymyxin E (1.57%), polymyxin B (2.36%), and doxycycline (3.94%) maintained low. The annual fluctuations in resistance to cefotaxime, piperacillin, ceftriaxone, tobramycin, doxycycline, minocycline and cotrimoxazole were statistically significant (all P<0.05). There were statistically significant differences in the resistance of clinical and environmental isolates to ampicillin/sulbactam, cefepime, ceftazidime, subamphetamine, meropenem, piperacillin, aztreonam, gentamicin, tobramycin, minocycline, ciprofloxacin, levofloxacin, and cotrimoxazole in the hospital from 2018 to 2023 (all P<0.05). The resistance rate of clinical isolates was generally high, especially to β-lactam and quinolone drugs, which were mostly above 80% [such as cefepime (93.86%), cefotaxime (97.37%), imipenem (98.25%), and ciprofloxacin (99.12%)]. The resistance rate of environmental isolated strains to similar antibiotics was relatively lower, mostly concentrated at 10%‒30%. The whole-genome sequencing of 34 carbapenem-resistant Acinetobacter baumannii (CRAB) strains isolated from the hospital environment in 2023 revealed that the main resistance mechanism was overexpression of efflux pumps (51.97%), followed by changes in target sites (32.46%). Among the 34 CRAB strains, carbapenem resistance genes OXA-23 and OXA-51 were detected in 6 strains (17.65%), while genes such as KPC, IMP, VIM, and SIM were not detected. ConclusionFrom 2018 to 2023, AB in the hospital environment exhibited high resistance rates to certain antimicrobial agents and carried multiple resistance genes, indicating a potential transmission risk. It is necessary to further strengthen bacterial resistance monitoring and hospital infection control, and use antibiotics reasonably.

ObjectiveTo determine the serum antibody level and risk factors in the adolescent population in a county in Zhejiang Province， following the immunization with inactivated COVID-19 vaccine， and to construct a prediction model for antibody concentration. MethodsWe conducted the study in a county in Zhejiang Province， employing a stratified cluster random sampling strategy in school children who had received the inactivated COVID-19 vaccine. Data on gender， age， type of vaccine， and time of vaccination was collected. Serum samples were also collected to test for anti-S and N IgG antibody against the SARS-CoV-2 by using chemiluminescent immunoassay （CLIA）. Risk factors were determined to construct a prediction model for antibody concentration. ResultsThe IgG antibody concentration was significantly higher in girls， those who received two doses， and those who had simply received the KX vaccine . It decreased with age and time interval between the sampling and last vaccination. The prediction model constructed by random forest regression in the study had a better model fit and predictive ability than that by the multivariable linear stepwise regression. ConclusionGender， age， vaccination dose， type of vaccine， and time of vaccination are associated with vaccination effectiveness of inactivated COVID-19 vaccines in adolescents. Prediction model could predict the antibody level in the vaccinated population， which can provide a new tool for better evaluation of vaccination effectiveness against emerging infectious diseases in future.

Aerosol microorganisms are important constituents of aerosols. They participate in physical and chemical reactions in the air and are also closely related to disease transmission and human health. With the SARS-CoV-2 pandemic， aerosol microorganisms have become a public health topic of great concern. Studying the composition and influencing factors of the air microbiome therefore has significant public health implications. Due to the limitations of traditional technologies for sampling and determination， the aerosol microbiome has not been fully understood. However， with the development and maturity of high-throughput sequencing technology， the aerosol microbiome has shown promising research prospects. This article reviews the composition， characteristics， detection methods and influencing factors of aerosol microorganisms， providing basic knowledge for further research on the air microbiome. In-depth research on microbial aerosols has significant implications on urban air quality control， national security and public health.

ObjectiveAntibiotic resistance genes （ARGs） have received wide attention all over the world. The purpose of this study was to explore the bacterial community structure， the types and levels of antibiotic resistance genes in a water body in east China， and to compare and analyze the characteristics of microbial species distribution and antibiotic resistance gene distribution in various water environments. MethodsA total of 10 households in Haimen City， Jiangsu Province were selected and their surrounding water environment samples were collected. 21 water samples including river water （4）， Mingou water （9） and well water （8） were collected for metagenomics sequencing， assembled with MetaWRAP， annotated with CARD database， and analyzed with R software. ResultsIn various water bodies， the dominant bacteria phyla was Proteobacteria， the dominant bacteria genera were Deuterostomia， Pseudomonas， Flavobacteriales and Streptomycetaceae. The ARGs annotated were mainly composed of quinolones， aminoglycosides， macrolides and beta-lactams antibiotic resistance genes. The top four relative abundance of resistance genes were macB， RanA， evgS and TxR， The average absolute abundance and expression of resistance genes in well water and Mingou water were higher than those in river water. ConclusionMultiple ARGs are detected to varying degrees in well water， river water， and Mingou water bodies， and the expression of resistance genes in well water and Mingou water bodies is higher than that in river water bodies， possibly due to human production and living activities.

ObjectiveTo investigate the specific anti-SARS-CoV-2 antibody in adults and above after initial vaccination with inactivated COVID-19 vaccine， and determine the influencing factors. MethodsIn this study， residents aged 18 and above who had completed two doses of inactivated COVID-19 vaccine in Deqing County， Huzhou City， Zhejiang Province were included. Information such as gender， age， type of vaccine and vaccination time were collected， and serum specimens were sampled. Anti-SARS-CoV-2 receptor binding domain （RBD） antibody was quantitatively examined by enzyma-linked immunosorbent assay （ELISA） and influencing factors were determined. ResultsThe median concentration of anti-SARS-CoV-2 IgG antibody in the residents vaccinated with an inactivated booster vaccine was higher than that in those vaccinated with only two doses of COVID-19 vaccine or single dose （P<0.05）. The median concentration of IgG antibody in males was 9.73 （4.01‒23.70） RU‧mL^-1， lower than 17.76 （7.07‒49.23） RU‧mL^-1 in females （P<0.05）. The median concentration in the residents vaccinated with BBIBP-CorV （Sinopharm） was 6.53 （0.97‒13.69） RU‧mL^-1， which was lower than that in those vaccinated with CoronaVac （Sinovac） that was 17.29 （8.54‒43.73） RU‧mL^-1 （P<0.05）. The median concentration in those with BBIBP-CorV was also lower than 12 （5.45‒40.06） RU‧mL^-1 in those with heterologous booster vaccine （P<0.05）. The median concentration was 9.73 （3.83‒23.63） RU‧mL^-1 in the residents with an interval of more than 6 months from the second dose， which was lower than 14.66 （6.36‒35.98） RU‧mL^-1 in those with an interval of 3‒6 months （P<0.05）. Moreover， immune effect was better in females （χ²=16.464， P<0.05）， 18‒45 years（χ²=7.158， P<0.05）， and those vaccinated with CornaVac （χ²=49.637， P<0.05）， while decreased in those with an interval of more than 6 months from the second dose （χ²=8.447， P<0.05）. ConclusionGender， age， and type of vaccine may affect the effect of immunization. The COVID-19 vaccination shows an acceptable immunogenicity in adults； however， it declines in 6 months after vaccination. It warrants strengthening the booster vaccination to maintain the immune response.

Drug-resistant bacteria have become a serious threat to human health. Polymyxin has shown strong bactericidal activity to some Gram-negative and Gram-positive bacteria that are resistant to antibiotics， and has become a last-resort treatment option against a variety of multi-drug resistant bacteria. However， due to the abuse of polymyxin in animal breeding， the drug resistance rate of polymyxin in human population has significantly increased. In order to further understand the mechanism of polymyxin resistance， and to take measures to reduce the incidence of polymyxin resistance in the population， this paper reviewed the progress in research of the antibacterial mechanism of polymyxin， the prevalence of polymyxin resistance in the population， the mechanism of polymyxin resistance， and its transmission mode.

Objective To explore the effects of different dietary induction models of inulin， resistant starch RS3 and their complexes on the body weight and intestinal flora in mice. Methods A total of 64 C57BL/6 mice were randomly divided into low-fat control group， low-fat inulin group， low-fat resistant starch RS3 group， low-fat composite group and high-fat control group， high-fat inulin group， high-fat resistant starch RS3 group and high-fat composite group for dietary intervention. The mice were weighed and fresh feces were collected weekly. Diet intervention was continued until the weight of the high-fat control group was more than 14% higher than that of the low-fat control group. The mice were then sacrificed after overnight fasting. Liver and epididymal fat were weighed， and the colon contents were collected for 16S amplicon sequencing analysis. Results In low-fat diet fed mice， the combined induction of inulin and resistant starch RS3 caused a significant decrease in body weight gain. In high-fat diet fed mice， inulin alone and the combined induction both caused a significant reduction in weight gain， and there was no significant difference between the two methods. In the high-fat diet groups， inulin， resistant starch RS3， and the compound could be distinguished by Bacteroides， Bifidobacterium and Alloprevotella respectively. In the low-fat diet groups， inulin， resistant starch RS3， and the composite groups could be distinguished by Coriobacteriaceae_UCG_002， Bacteroides and Helicobacter， respectively. Conclusion Inulin and resistant starch RS3 diet induction can significantly reduce the weight gain of C57BL/6 mice， change the structure of intestinal flora， and show the difference between high-fat and low-fat diets. Inulin and resistant starch RS3 may reduce body weight and promote fat metabolism by changing the structure of intestinal flora.

Objective: To investigate surface electromyography signal (sEMG) of the major back muscle group and subjective fatigue assessment under different experimental combinations during walk with weight on both shoulders, as well as the functional status and fatigue property of human muscles. Methods: From October to December, 2017, 10 college students were recruited to participate in shoulder weight-bearing work and walk under the combinations of different shoulder strap widths, weights, and hardness of waist cushion. The subjects were required to complete 12 sets of experiments, with each set lasting for 15 minutes, and the rest time between work was 30 minutes. The sEMG signals of the upper trapezius and the erector spinae were measured during the experiment, and subjective fatigue assessment was performed during rest. The time domain evaluation index (average amplitude, aEMG) , the frequency domain evaluation index (median frequency, MF) , and the data of subjective assessment were processed and analyzed. Results: Weight and shoulder strap width had a significantly effect on fatigue (P<0.01) , and the change in the hardness of waist cushion had no significant effect on fatigue (P>0.05) . There was an interaction effect between weight and shoulder strap width (P<0.01) , and there was no interaction effect between weight, shoulder strap width, and hardness of waist cushion (P>0.05) . For the backpack carrying system, the combination of 10% weight and 50 mm shoulder strap width was the best one for relieving fatigue. The subjective test also showed that subjective feelings of muscle fatigue were associated with the weight and width, which was consistent with sEMG results. Conclusion The results of this experiment show that the combination of 10% weight and 50 mm shoulder strap width can help to relieve muscle fatigue during walk with weight on both shoulders, and weight-bearing walking is more likely to cause the fatigue of the erector spinae.

Objective To measure the titers of varicella live attenuated vaccines ( VarV) during the process of transportation and storage in different seasons and communities of Minhang Distract, Shang-hai, to evaluate the operation of cold chain system and the thermal stability of vaccines and to provide refer-ences for the management, introduction, research and development of vaccine in future.Methods Four communities with high outbreak rates of varicella during 2012 to 2013 and four communities with low out-break rates were randomly selected from 13 communities in Minhang District, Shanghai.The titers of VarVs were detected by using the quantitative plaque assay before and after 30 days of storage in November 2013 and February, May, August 2014.Results The overall rate of qualified VarVs was 90.63% with a geo-metric mean titer (GMT) of 3.67 (LgPFU/0.5 ml).96.88%of the VarVs produced by company C met the quality standard with a GMT of 3.89 ( LgPFU/0.5 ml) followed by those produced by company B with a rate of 91.67%and a GMT of 3.75 ( LgPFU/0.5 ml) .The rate of qualified VarVs produced by company A was the lowest, which was 80.00%, with GMT of 3.29 (LgPFU/0.5 ml).There were significant differences in the rates of qualified VarV among the three companies (χ2=8.288, P=0.016).The rate of qualified vac-cines in communities close to the Shanghai Minhang Center for Disease Control and Prevention ( Minhang CDC) was 91.67%, while 100%of the vaccine samples collected form the communities at a middling dis-tance from or far from the Minhang CDC met the quality standard.No significant difference in the rate of qualified vaccine was found among the three types of communities (χ2=3.441, P=0.179).The quarterly rates of qualified vaccines produced by B and C companies were 100%except for the third quarter.The rates of qualified vaccines produced by A, B and C companies in the third quarter were respectively 70.00%, 66.67%and 87.50%.No statistical differences in the quarterly rates of qualified vaccines were found among the three companies (χ2=1.25, P=0.7412;χ2=6.545, P=0.088; χ2=6.194, P=0.103).No statistical differences in the rates of qualified vaccines before and after 30 days of storage were found among the three companies (χ2=0.625, P=0.347;χ2=0.000, P=1.000;χ2=2.065, P=0.492).Conclusion A well-managed and-operated cold chain system was implemented in Minhang District in the storage and transport of vaccines as well as other related links.The thermal stability of vaccines produced by company C was better than those of the other two companies.A surveillance for the titers of vaccines produced by com-pany A should be strengthened.

OBJECTIVESTo survey on the vaccination of varicella live attenuated vaccine among 4-17 children in Minhang District, and analyze the protective effect against varicella.

METHODSWe collected outbreak chickenpox cases reported from infectious disease report system and surveillance units in Minhang district from 1st May in 2012 to 30th Apr in 2013. The 1: 3 matched case-control study was conducted to questionnaire the legal guardian of the cases and control group, and calculate the protective effect and effective term of protection. The survey included vaccination, chickenpox exposure history, previous history of varicella illness, suffering from the symptoms of chickenpox, the vaccinations brand, etc. The criteria of accepted case were those healthy students who were in the same class with those chickenpox cases. The accepted matched controlling data were those children who were from the same class with outbreak chickenpox cases without varicelliform eruption, similar live condition, the closest house, the same gender, the closest age. This study investigated 390 cases of patients and the control group included 1 170 cases. Chi-square test was used to compare the vaccination of cases and controls, as well as the incidence of chickenpox vaccination different brands VarV, Mantel-Haenzel chi-square test was applied to compare the protective effect of the two groups.

RESULTSVarV overall vaccination rate was 68.3% (1 065/1 560), among them, the case group coverage was 45.1% (176/390), significantly lower than the control group (76.0% (889/1 170)) (χ² = 128.55, P < 0.01). The coverage in children of 4-10 years old group was 88.4% (375/424), significantly higher than the 11-17 years old group (60.7% (690/1 136)) (χ² = 109.40, P < 0.01). The overall protective effect of VarV was 78.10% (71.82%-82.98%).Vaccinated group incidence ratio was 16.5% (176/1 065), significantly lower than the unvaccinated group (43.2% (214/495)) (χ² = 128.55, P < 0.01). The chickenpox risk of the children who were vaccinated was lower than those who were not, and the OR (95%CI) was 0.22(0.17-0.28) . Proportion of the fever and the typical symptoms of varicella zoster were 26.1% (46/176), 8.0% (14/176) in the children vaccinated VarV, significantly lower than children without VarV vaccination history (54.7% (117/214) , 18.2% (39/214) ) (χ² values were 32.33 and 8.67, respectively. P values both <0.01). The varicella incidence was 17.4% (139/797) in children vaccinated domestic VarV, and it was 13.8% (37/268) in the group of imported VarV (χ² = 1.92, P = 0.184) . The average duration of effective protection period for domestic and imported VarV was (6.2 ± 2.7), (6.3 ± 3.4) years (F = 2.24, P = 0.136).

CONCLUSIONSThe risk of varicella incidence and the proportion of fever or typical varicella zoster were lower in the one dose of VarV vaccinated; Effective protective effect was consistent in the children with domestic or imported VarV vaccination.

Adolescent ; Case-Control Studies ; Chickenpox ; Chickenpox Vaccine ; Child ; Child, Preschool ; China ; Disease Outbreaks ; Fever ; Humans ; Immunity, Active ; Incidence ; Risk ; Surveys and Questionnaires ; Treatment Outcome ; Vaccination ; Vaccines, Attenuated