Abstract:Objective To analyze the molecular characteristics and prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolated from the intensive care unit (ICU), and provide laboratory data for infection control and antimicrobial treatment. Methods 51 CRKP strains isolated from ICU of a hospital from July 2018 to July 2020 were collected, minimum inhibitory concentration (MIC) was determined by broth microdilution method, homology of strains was analyzed by multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE), resis-tance and virulence genes of strains were detected, transferability of plasmid was verified with conjugation testing. Results Antimicrobial susceptibility testing showed that CRKP strains were all susceptible to ceftazidime/avibactam, resistance rate to tegacyclin was the lowest (3.9%), followed by amikacin (49.0%) and polymyxin (64.7%), while strains were all highly resistant to imipenem (96.1%), meropenem (98.0%), levofloxacin (98.0%) and ceftazidime (100.0%). Among 51 CRKP strains, 49 strains (96.1%) were positive in mCIM testing, 1 strain (2.0%) was positive in eCIM testing. Carbapenemase gene bla_KPC-2 positive strains accounted for 96.1%. Among all isolates, 4 strains (7.8%) exhibited the hypermucoviscous phenotype, positive rates of virulence genes were uge (100.00%), mrkD (94.1%), kpn (94.1%), fim-H (72.5%), aero (2.0%), and rmpA (2.0%). ST11 and ST1373 CRKP accounted for 98.0% (50/51) and 2.0% (1/50) respectively among ICU strains. One highly virulent Klebsiella pneumoniae strain ST1373 was isolated. The success rate of conjugation testing of bla_KPC-2-harboring strains was 12.2%. Conclusion There is a monoclonal transmission of ST11 CRKP that produces KPC-2 in ICU, and it carries certain virulence genes. The plasmid of bla_KPC-2-harboring gene can be transmitted horizontally through conjugation. Ceftazidime/avibactam has high susceptibility to CRKP and can be used in clinical treatment.

Abstract:Objective To investigate the rapid identification of bla_KPC-2-harboring Klebsiella pneumoniae (K. pneumoniae) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Methods K. pneumoniae isolated from hospitalized patients in the First Affiliated Hospital of Bengbu Medical College from September 2018 to November 2020 were collected, antimicrobial susceptibility testing was performed by disk diffusion method. bla_KPC-2-harboring K. pneumoniae was screened by polymerase chain reaction (PCR). MALDI-TOF MS was used to identify the strains, the mass spectra of bla_KPC-2-harboring K. pneumoniae and carbapenems-sensitive K. pneumoniae (CSKP) were collected, 70 strains were selected respectively to establish the Super-Spectra of bla_KPC-2-harboring K. pneumoniae and CSKP. K. pneumoniae except strains in Super-Spectra were also identified for judging whether the identification results were accurate according to antimicrobial resistance phenotype and PCR results. Results A total of 143 carbapenems-resistant K. pneumoniae (CRKP) strains and 152 CSKP strains were screened out from 295 K. pneumoniae strains. 140 CRKP strains were identified carrying carbapenemase gene (134, 3, 2, and 1 strains were found bla_KPC-2, bla_KPC-18, bla_NDM-1 and bla_IMP respectively), 3 strains didn't harbor carbapenemase gene, 2 strains were found both bla_KPC-2 gene and bla_NDM-1 gene. According to the require-ment of database establishment, a Super-Spectra of bla_KPC-2-harboring genotypes of K. pneumoniae and CSKP were established; the coincidence rate of the two was 80% when the error value was < 0.5; according to the comparison map, the five peaks of 4 154.4m/z, 8 310.7m/z, 10 880.8m/z, 3 579m/z and 10 079.3m/z could be used as the characteristic peaks to distinguish the bla_KPC-2-harboring K. pneumoniae and CSKP. 155 strains of K. pneumoniae except Super-Spectra were selected for verification, the accuracy rate was 92.90% (144/155); the accuracy of bla_KPC-2-harboring K. pneumoniae was 94.52% (69/73), and that of CSKP was 91.46% (75/82). Conclusion The establishment of Super-Spectra through MALDI-TOF MS can rapidly predict bla_KPC-2 genotype K. pneumoniae, which is helpful to provide a reliable laboratory basis for the diagnosis and treatment of CRKP infection as well as prevention and control of healthcare-associated infection.

Abstract:Objective To study the clinical characteristics and virulence gene distribution of Staphylococcus aureus (SA) of different infection types. Methods SA isolated from 11 member hospitals in Baotou which participates the national bacterial resistance monitoring network from January 2018 to December 2020 were collected. Medical records of patients with included strains were analyzed retrospectively, clinical characteristics of infection and antimicrobial resistance were analyzed. The strains were conducted stratified sampling, samples were taken as the tested strains for virulence gene detection. WHONET 5.6 and SPSS 22.0 software were used for data analysis. Results A total of 2 452 SA strains were collected. There were 932 cases of surgical infection, 504 cases of respiratory tract infection, 172 cases of blood stream infection and 844 cases of other types of infection. Patients with SA infection were mainly females (68.23%). There were significant differences in the distribution of infection types among SA infected patients of different gender and age (all P < 0.001). Surgical infection, respiratory tract infection and blood stream infection mainly occurred in patients < 60 years old. Patients with surgical infection had a higher proportion of hospitalization time >2 weeks, accounting for 39.21%. The mortality of patients with SA respiratory tract infection was 76.39%. The levels of white blood cell count, neutrophil count, percentage of neutrophils, platelet count, and prothrombin time in patients with different types of infection were all significantly different (all P < 0.05). There were significant differences in the levels of C-reactive protein, procalcitonin, interleukin-6, D-dimer, and fibrinogen degradation products of patients with different infection types (all P < 0.05). Antimicrobial resis-tance rates of MRSA causing different types of infection to ciprofloxacin, gentamicin, levofloxacin and moxifloxacin were significant (all P < 0.05). Carrying rate of clfa, clfb, scn, coa, nuc, hla, hld were all high in different types of infection (>94), proportion of LukED in surgical infection was higher than that of the other three types of infection, difference was significant (P < 0.05). Conclusion Clinically isolated SA carries more virulence genes and has high toxicity, and there are differences in antimicrobial resistance among different types of SA infection.

Abstract:Objective To study the polymorphism and epidemic characteristics of the Beijing genotype strains of Mycobacterium tuberculosis (Mtb) in Yichang area, reveal the molecular epidemiological characteristics of tuberculosis in this area, and provide scientific evidence for the prevention and treatment of tuberculosis. Methods 298 strains of Mtb with complete case information from January 2018 to December 2019 were selected for the identification of human Mtb, Beijing genotype strains were identified by multiplex polymerase chain reaction (DTM-PCR) which amplifying RD105 deletion fragment; polymorphism of Beijing genotype strains was analyzed by optimized 9-locus variable-number tandem repeat technique. Results Among 298 strains of Mtb, 260 strains were human Mtb, DTM-PCR identification found that 140 strains (53.85%) were Beijing genotype and 120 strains (46.15%) were non-Beijing genotype. Drug resistance rate of Beijing genotype strains was higher than that of non-Beijing genotype strains (32.14% vs 10.83%, P < 0.05). The resolution of VNTR-9 locus to Beijing genotype strains was 0.998 5 and the clustering rate was 12.15%. Conclusion Beijing genotype strains showed a high prevalence trend in Yichang area, drug resistance rate of Beijing genotype strains is higher. VNTR-9 genotyping method used to identify Beijing genotype strains of Mtb in this area can accurately reflect the molecular epidemiological characteristics of Mtb in Yichang.

Abstract:Objective To study in vitro antimicrobial activity of combination of avibatam (fixed concentration of 4 μg/mL) and β-lactam antibiotics against carbapenem-resistant Klebsiella pneumoniae(CRKP). Methods Non-repetitive CRKP strains isolated from a hospital were collected, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ceftazidime/avibatam, aztreonam/avibatam, and meropenem/avibatam against CRKP was detected with broth microdilution method, carbapenemase resistance genes were determined by polymerase chain reaction (PCR). Results Among 63 CRKP strains, 57 strains harbored bla_KPC gene, 5 strains harbored metalloenzyme gene, and 1 strain did not found common carbapenem-resistant gene. Among 57 CRKP strains with positive bla_KPC gene, MICs of ceftazidime/avibatam, aztreonam/avibatam, and meropenem/avibatam were ≤8/4, 4/4, and 0.5/4 μg/mL respectively, avibatam significantly decreased the MIC₅₀ and MIC₉₀ values of ceftazidime, aztreonam and meropenem. Among 5 CRKP strains with positive metalloenzyme gene, avibatam did not decrese MIC₉₀ of ceftazidime and meropenem, but decreased MIC₉₀ of aztreonam by 99.8%, MBC₅₀ and MIC₅₀ of three compound of avibatam against 63 strains of CRKP were identical, their MBC₉₀ and MIC₉₀ were identical. Conclusion Combination of avibatam with three common β-lactam antibiotics (ceftazidime, aztreonam and meropenem) has a good antimicrobial effect on CRKP strains expressing KPC-2 carbapenemase, combination with ceftazidime or meropenem has no inhibitory effect on metalloenzyme-harboring CRKP strains, but combination with aztreonam has a good antimicrobial effect on metalloenzyme-harboring CRKP strains.

Abstract:Objective To summarize the clinical features, diagnosis and treatment methods of cervical necrotizing fasciitis (CNF) combined with descending necrotizing mediastinitis (DNM). Methods Medical records of 6 patients with CNF combined with DNM and treated in the Second Affiliated Hospital of Kunming Medical University from January 2015 to May 2020 were analyzed retrospectively. Results Six patients all underwent neck debridement and drainage in the early stage, 2 of whom underwent thoracoscopic mediastinal incision and drainage, 1 underwent chest wall debridement, and 5 underwent tracheotomy due to dyspnea caused by tracheal compression. After operation, antimicrobial use was adjusted according to antimicrobial susceptibility testing results, patients continued anti-infection and nutritional support, actively treated underlying diseases, rinsed the wound every day, strengthened dressing change, and performed debridement once and 4 times in 2 cases respectively. All 6 patients had fever, as well as symptoms of neck and chest during disease course, which progressed rapidly. Infection indicator procalcitonin (PCT) and C-reactive protein (CRP) were both high, multiple honeycomb pneumatosis ("bubble sign") in the neck was found through neck thoracic CT, and extended to the mediastinum. 3 cases were cured and 3 cases died. The cured cases were followed up for 1-4 years and recurrence was not found. Conclusion The "bubble sign" showed by neck and chest CT is the "gold standard" for early diagnosis of CNF combined with DNM, the key to cure the disease lies in early diagnosis, timely surgical debridement and drainage.

Abstract:Objective To analyze the network characteristics and regional collaborative relationship of medical institutions that regularly respond to epidemic events of major infectious diseases, and provide reference for the optimization of regional medical treatment system with the combination of regular and emergency. Methods 344 fever clinics and 120 designated treatment hospitals in Hunan Province are selected as the research objects, geographic information system (GIS) method is adopted to construct the spatial association between fever clinics and designated hospitals, social network analysis (SNA) is adopted to analyze the centrality and cluster of collaborative network of medical institutions, and based on Yifan Hu force-directed graph drawing show algorithm for network visualization. Results There are 344 nodes and 887 edges in the collaborative network between fever clinics and designated hospitals; among the designated hospitals at the provincial, municipal and county levels, the First Hospital of Changsha, Xiangtan Central Hospital, and the People's Hospital of Wangcheng Distric have stronger radiation capacity than institutions of the same level, the First Affiliated Hospital of University of South China, Loudi Central Hospital, and the People's Hospital of Lianyuan are relatively "independent". The First Affiliated Hospital of University of South China, Central Hospital of Shaoyang and the People's Hospital of Lianyuan play the role of "Bridges" in the collaborative network; the modularity value of the collaborative network is 0.687, and the spatial clustering forms 5 groups. Conclusion Medical collaborative network in regular response to epidemic events of major infectious diseases in Hunan Province presents the structure of "four districts and one hub", including the regional sub-network cove-ring four provincial designated hospitals and multiple cities, as well as the hub-type sub-network covering a single ci-ty and connecting with multiple districts; the designated hospitals in the collaborative network can be divided into three types: central type, support type and substitute type. In order to form an effective and orderly regional emergency coordination mechanism, it is suggested to refine the function positioning according to the types of designated hospitals and sign inter-city collaborative agreements according to the main collaborative areas.

Abstract:Objective To clarify the difference in the recovery rate of bacterial test methods of surgical masks between China and the European Union (EU). Methods The recovery rate of test methods in Medical face masks (YY 0469-2011) issued by China and Medical face masks-Requirements and test methods (EN 14683-2019) was compared, the best link of the two methods was explored. Results The recovery rate of EN 14683-2019 test method was as high as 65.1%, which was nearly 4 times higher than that of YY 0469-2011 criteria; the elution method was mechanical shaking, and the elution effect was not as good as manual shaking (recovery rate was 68.6%); the acceptable criteria of EN 14683-2019 was stricter than that of YY 0469-2011. Conclusion The eluent of EN 14683-2019 contains surfactant (Tween 20), which improves the recovery rate of the test method; the elution effect of manual shaking in YY 0469-2011 method is better than that of mechanical shaking in EN 14683-2019 method.

Abstract:Objective To establish nomogram model for individualized prediction of risk for pulmonary infection (PI) in elderly patients with acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI), and verify the prediction efficiency of the model. Methods 215 elderly AMI patients who underwent PCI in a hospital from July 2018 to June 2021 were selected as the research object, clinical data of patients were collected, distribution of pathogens of post-operative PI was analyzed, risk factors for PI after PCI were conducted univariate, LASSO regression and multivariate regression analysis, and nomogram risk model was established. Results 39 patients had PI, infection rate was 18.14%, 43 pathogenic strains were isolated, 67.44% of which were Gram-negative bacteria. Multivariate regression analysis showed that age ≥70 years, smoking, diabetes mellitus, Killip grade III-IV, tracheal intubation and mechanical ventilation were independent risk factors for PI in elderly AMI patients after PCI (all P < 0.05). The model verification results show that C-index was 0.823; there was no significant difference in H-L deviation test results(χ²=4.122, P=0.537); the area under receiver operating characteristic curve was 0.840 (95%CI: 0.805-0.875); the net benefit predicted by the model was high in the range of 1%-96%, indicating that the model has good prediction efficiency. Conclusion Age ≥70 years old, smoking, diabetes mellitus, Killip grade Ⅲ-Ⅳ, tracheal intubation and mechanical ventilation are significantly associated with post-operative PI in elderly AMI patients after PCI, the nomogram model established based on this can be effectively predict the risk for PI.

Abstract:Objective To explore the clinical characteristics and prognosis of secondary acute promyelocytic leukemia (APL) after therapy for hemophagocytic lymphohistiocytosis (HLH). Methods Clinical data of a child with Brevibacterium epidermidis infection-associated HLH and progressed to secondary APL following etoposide (VP16) therapy were collected, 17 cases reported in the literatures at home and abroad were reviewed. Results A case of Brevibacterium epidermidis infection-associated HLH treated in a hospital had secondary APL after receiving HLH-04 regimen, APL went into remission and patient survived after chemotherapy. 17 cases of secondary leukemia after therapy for HLH reported in literatures were reviewed, a total of 18 cases were included in analysis, 13 were males and 5 were females, the age of patients with the first diagnosis of HLH was 0-19 years (median 3 years), among the HLH types, EB virus infection-associated HLH accounted for 61%, the cumulative dose of VP16 was 400-20 500 mg/m² (median 3 100 mg/m²); the latent time of secondary leukemia was 6-72 months (median 26 months). Six of 18 cases died and 12 survived, 6 cases of M3 achieved complete remission and survived after chemotherapy. Conclusion Infection-associated HLH is a common type of primary disease in HLH-associated leukemia, APL has a high incidence among secondary leukemia. During therapy for HLH, it is necessary to pay attention to the cumulative dose, frequency of administration and combination regimen of VP16, as well as individual differences of patients, molecular biology of bone marrow is helpful to monitor the occurrence of secondary leukemia.

Abstract:Objective To understand the infection status and disease spectrum distribution of patients with multidrug-resistant organism (MDRO) infection in an intensive care unit (ICU), and provide basis for the prevention and control of MDRO infection. Methods Clinical data of patients in the ICU of a tertiary first-class hospital from January 2018 to December 2020 were analyzed, differences in disease spectrum of patients with MDRO infection in ICU (case group), patients without MDRO infection in ICU (control group), and patients with MDRO infection in non-ICU were compared. Results The overall constituent of patients with MDRO infection in ICU showed an upward trend; the majority of infected patients were male, most of whom were the elderly, mortality of MDRO-infected patients was higher than that of uninfected patients. MDRO-infected patients directly admitted to ICU accounted for the highest proportion in the whole MDRO-infected patients. Acinetobacter baumannii ranked first among strains isolated from MDRO-infected patients in ICU, Escherichia coli ranked first among strains isolated from MDRO-infected patients in non-ICU; the disease spectrum of the first two groups was similar, with respiratory diseases ranking first, mainly pulmonary infection; the disease spectrum of patients without MDRO infection in ICU was hypertension, which was different from that of infected patients. The order of different diseases also changed in varying degrees with the increase of years. Conclusion The disease spectrum of patients with MDRO infection is complex and diverse, scientific, accurate and standardized treatment should be achieved, treatment of respiratory diseases should be paid attention, and the implementation of infection prevention measures should be strengthened.

Abstract:Objective To analyze the risk factors for surgical site infection (SSI) in patients with hepatic hydatidosis. Methods Patients who underwent surgery for hepatic hydatidosis in Qinghai Provincial People's Hospital from January 2017 to December 2020 were selected, according to whether there was SSI, they were divided into infection group and control group. Medical data of patients were analyzed retrospectively, risk factors for SSI in patients with hepatic hydatidosis were analyzed by univariate and multivariate logistic regression analysis. Results A total of 681 patients were included, there were 59 cases of SSI, with an infection rate of 8.66%, including 23 cases of incisional infection, 28 cases of abdominal infection, 6 cases of incisional+abdominal infection and 2 cases of subphrenic infection. A total of 63 strains of pathogens were isolated from infected patients, Gram-negative and Gram-positive bacteria accounted for 63.49% and 34.92% respectively. Pseudomonas aeruginosa, Acinetobacter baumannii and Enterococcus faecalis accounted for 17.46%, 9.53% and 7.94% respectively. Multivariate logistic regression analysis showed that diabetes mellitus, history of surgery for hepatic hydatidosis, post-operative bile leakage, indwelling time of drainage tube ≥15 days, and duration of surgery ≥250 minutes were independent risk factors for SSI in patients with hepatic hydatidosis (all P < 0.05). Conclusion There are multiple risk factors for SSI in patients with hepatic hydatidosis, actively controlling blood glucose during and after surgery, avoiding the recurrence of hepatic hydatidosis as much as possible to reduce the surgery for hepatic hydatidosis, actively preventing post-operative bile leakage, shortenning operation time and reducing the indwelling time of drainage tube can play a positive role in the prevention of SSI.

Abstract:Objective To explore the application effect of micro-lecture combined with BOPPPS teaching mode in practical teaching of isolation and precaution technique among medical students. Methods Medical students in grade 2020 from Anhui University of Chinese Medicine and receiving standardized training were selected as the research object, according to cluster random sampling, they were divided into trial group and control group. Control group adopted the teaching mode of traditional multi-media combined with on-site practical demonstration, while trial group adopted the teaching mode of micro-lecture combined with BOPPPS mode. After class, two groups were assessed in theory and practice, and the satisfaction for teaching effect was investigated through anonymous questionnaire. Results A total of 454 medical students were selected as the research object, 240 were in trial group and 214 in control group. The age of trial group and control group were (23.92±3.84) and (23.60±3.21) years old respectively. The score of theoretical examination in trial group was higher than that in control group ([89.44±8.41] points vs [82.76±10.08] points, P < 0.001). The score of practical skill examination in trial group was higher than that in control group ([96.01±1.62] points vs [95.42±2.35] points, P=0.002). The satisfaction of students in trial group in stimulating learning interest and improving autonomous learning ability was higher than that of students in control group (both P < 0.05). Conclusion The teaching mode of micro-lecture combined with BOPPPS can effectively improve students' learning effect, stimulate learning interest and cultivate autonomous learning ability, thus improving teaching quality.

Abstract:Objective To evaluate the effect of antimicrobial stewardship program (ASP) on carbapenem antibiotics in intensive care unit (ICU). Methods Clinical data of ICU patients in a hospital from April 1, 2018 to March 31, 2020 were retrospectively analyzed, ASP was implemented from April 1, 2019, the frequency of defined daily doses (DDDs) and antimicrobial use density (AUD) of carbapenem antibiotics were used as the evaluation criteria of ASP. Results Before and after implementation of ASP, there was no significant difference in general data of patients, length of ICU stay and mortality between infected and non-infected patients (all P>0.05). After the implementation of ASP, DDDs of carbapenem antibiotics decreased from 2 101.25 to 1 862.25, difference was not significant (P>0.05); AUD of carbapenem antibiotics decreased from 43.34 DDDs/100 cases·day to 31.32 DDDs/100 cases·day, difference was significant (P < 0.05). Resistance rates of Acinetobacter baumannii and Klebsiella pneumoniae to carbapenem antibiotics decreased from 90.00% and 20.41% before implementation to 73.21% and 10.14% after implementation respectively, difference was significant (both P < 0.05). Conclusion The implementation of ASP centered in ICU can reduce the DDDs and AUD of carbapenem antibiotics, reduce resistance rate of bacteria to carbapenem antibiotics, but does not increase length of ICU stay and mortality of patients.

Abstract:Mucosal immunity is a significant component of the whole immune network of the body, and it is also a unique immune system with unique structure and function, which plays an important role in resisting infection and is the first immune barrier for the body to resist infection. In recent years, more and more studies have reported that microRNAs (miRNAs) is important in the regulation of immune function, and miR-146a is one of the most important miRNAs that coordinates immune response and inflammatory signals, which plays a key role in a variety of biological processes and pathways, including immune response. This paper reviewed the research progress of miR-146a and mucosal immunity.

Abstract:Objective The outbreak of coronavirus disease 2019 (COVID -19) epidemic in 2020 has strongly promoted the development and application of severe acute respiratory syndrome coronavirus 2 vaccine, however, universal vaccination is hindered by vaccine hesitancy. This paper reviews COVID -19 vaccine hesitancy of different countries, analyzes the factors influencing the COVID -19 vaccine hesitancy based on the existing relevant models, and puts forward intervention measures for COVID -19 vaccine hesitancy, so as to provide reference for reducing vaccine hesitancy.