In 2023，World Health Organization（WHO）announced that the pandemic of COVID-19 is over；while there was an epidemic of multi-pathogenic infections in the respiratory tract by the end of the year in China，indicating that high attention still need to be paid to infectious diseases. In the past one year，some breakthroughs for infectious diseases have been achieved.This article reviews the major events and research progress in the diagnosis，prevention and treatment of infectious diseases in 2023.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

Objective:To investigate the diagnostic value of nucleic acid matrix-assisted laser desorption ionization-time of flight mass spectrometry（MALDI-TOF MS）in sputum smear-negative patients with nontuberculous Mycobacterial（NTM）pulmonary disease.Methods:Clinical data of 123 patients suspected of NTM pulmonary disease admitted in Public Health Clinical Center Affiliated to Shandong University between July 2022 and November 2023 were retrospectively analyzed. Bronchoalveolar lavage fluid（BALF）specimens were collected for MALDI-TOF MS assay and MGIT 960 culture. The diagnostic efficacy of MALDI-TOF MS for NTM pulmonary disease in patients with negative sputum smears for acid-fast bacilli was evaluated with receiver operating characteristic（ROC）curve. Statistical analysis was performed using SPSS 26.0 software and MedCalc statistical software.Results:Diagnosis of NTM pulmonary disease was finally confirmed in 66 out of the 123 suspected patients. It took 8 to 24 h for MALDI-TOF MS to identify NTM species and resistance. By MALDI-TOF MS，72 NTM strains were identified，with the Mycobacterium avium complex being the most prevalent（34 strains，47.22%），followed by the Mycobacterium abscessus complex（13 strains，18.06%）；resistance to macrolides was detected in 6 cases，while no resistance to aminoglycosides was found. It took 9 to 45 days for BALF MGIT 960 culture to identify NTM，and took 7 to 15 days for NTM typing and drug sensitivity testing. By BALF MGIT 960 culture，28 NTM strains were identified；and 1 case was found to be resistant to macrolides. Using confirmed diagnosis as the gold standard，MALDI-TOF MS demonstrated higher sensitivity，negative predictive value，and agreement rate compared to MGIT 960 culture（84.85% vs. 42.42%，81.13% vs. 56.32%，80.49% vs. 62.60%， χ2=25.667，8.998，9.664， P<0.05 or <0.01）. The area under ROC curve（AUC）for MALDI-TOF MS was significantly higher than that of MGIT 960 culture（0.801 vs. 0.642， Z=3.300， P=0.001）. Conclusion:Compared to MGIT 960 culture，MALDI-TOF MS exhibits superior diagnostic efficiency in detecting NTM pulmonary disease in patients with acid-fast bacilli smear-negative sputum，with advantage of rapidly identifying NTM species and resistance.

It is generally accepted that Mycoplasma hominis and Ureaplasma urealyticum are primarily found in the genitourinary tract and rarely enter the tissues and bloodstream. In recent years，cases of extra-genitourinary system infections caused by Mycoplasma hominis and Ureaplasma urealyticum have been increasing with a trend of multi-drug resistance，while detection and diagnosis are difficult，leading to treatment delay clinically. This article reviews the latest research progress on the pathogenic characteristics，laboratory diagnosis，infection types，and treatment options of extra-genitourinary system infections caused by Mycoplasma hominis and Ureaplasma urealyticum，in order to provide reference for etiological diagnosis and treatment of the infection.

Sepsis is a pathological condition in which the body’s response to infection is dysfunctional and may lead to life-threatening organ failures as one of the leading causes of death worldwide. However，there is still a lack of effective prevention and treatment for sepsis. IL-17A is an inflammatory cytokine produced primarily by activated T cells and is involved in host defense，tissue repair，the pathogenesis of inflammatory diseases，and the progression of cancer. This article reviews the recent research progress on the roles of IL-17A in sepsis-related organ damage，and its potentials as a novel therapeutic target for the clinical treatment of sepsis.

Objective:To evaluate the clinical value of combined detection of placenta associated 8 (PLAC8) and platelet activating factor acetylhydrolase (PLA2G7) for early identification of sepsis and non-infectious systemic inflammatory response syndrome (SIRS).Methods:A cross-sectional study was conducted. A total of 189 febrile patients suspected infection who were admitted to Huashan Hospital, Fudan University from October 2022 to April 2023 were included. Based on etiological, laboratory test results and clinical data, patients were classified as infection or non-infection, and further classified as sepsis or non-infectious SIRS according to diagnostic criteria. Real-time fluorescence polymerase chain reaction was used to detect the mRNA levels of PLAC8 and PLA2G7 in peripheral venous blood of patients. Hematology, inflammatory markers including C-reactive protein (CRP), interleukin-6 (IL-6) and procalcitonin, sepsis-related organ failure assessment (SOFA) score, and the difference of cycle threshold (Ct) values between PLA2G7 and PLAC8 ((PLA2G7-PLAC8)ΔCt value))were compared between the sepsis and non-infectious SIRS groups. Statistical comparison was analyzed using Mann-Whitney U test, and the diagnostic performance of (PLA2G7-PLAC8)ΔCt value in discriminating sepsis from non-infectious SIRS was evaluated using receiver operating characteristic curve. Results:Among the 189 febrile patients suspected infection, there were 80 non-infectious patients, including 51 non-infectious SIRS patients, and 109 infection patients, including 53 sepsis patients. The neutrophil ratio, CRP, IL-6, procalcitonin, and SOFA score of non-infectious SIRS patients were lower than those of the sepsis group, and the differences were all statistically significant ( Z=-2.70, -3.11, -2.16, -3.76 and -2.33, respectively, all P<0.05). The (PLA2G7-PLAC8)ΔCt value in the non-infectious SIRS group was 4.38(1.41), which was lower than 8.18 (6.19) in the sepsis group, with a statistically significant difference ( U=193.50, P<0.001). The area under the receiver operating characteristic curve (AUROC) for (PLA2G7-PLAC8)ΔCt value in the differential diagnosis of sepsis and non-infectious SIRS was 0.859, with the optimal cut-off value of 5.86. The sensitivity and specificity were 82.2% and 71.9%, respectively. When combined with procalcitonin, the AUROC was 0.917, with a sensitivity of 95.6% and specificity of 70.6%. Conclusions:The (PLA2G7-PLAC8)ΔCt value in peripheral blood has good clinical value for early identification of sepsis and non-infectious SIRS, especially when combined with procalcitonin, which could further improve the accuracy of differential diagnosis.

Objective:To investigate the clinical characteristics and prognosis of bloodstream infection caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) in preterm infants, and to provide basis for early clinical diagnosis and infection control. Methods:The clinical data of infants with CRKP bloodstream infection admitted to the Preterm Infants Ward of Children′s Hospital Affiliated to Zhengzhou University from January 2015 to December 2022 were retrospectively analyzed. The risk factors for death in preterm infants caused by CRKP bloodstream infection were explored through multivariate logistic regression analysis, and the receiver operating characteristic (ROC) curve was used to analyze the clinical value of each factor on evaluating prognosis. The area under curves (AUC) of each factor in different ROC curve were compared by Delong′s test.Results:A total of 96 preterm infants with CRKP bloodstream infection were included, including 70 in the survival group and 26 in the death group. The first onset symptoms of CRKP bloodstream infection in preterm infants were persistent tachycardia (heart rate>180 per minute) (69 cases, 71.9%), fever (61 cases, 63.5%), and apnea (59 cases, 61.5%). There were 88(91.7%) cases of infection combined with septic shock, and 91(94.8%) cases required vasoactive drug support. Multivariate logistic regression analysis showed that the maximum vasoactive-inotropic score (VIS) within 48 hours of onset (odds ratio ( OR)=1.058, 95% confidence interval (95% CI) 1.022 to 1.095, P=0.001), concurrent purulent meningitis ( OR=8.029, 95% CI 1.344 to 47.972, P=0.022), and concurrent necrotizing enterocolitis (NEC) ( OR=10.881, 95% CI 1.566 to 75.580, P=0.016) were independent risk factors for death in preterm infants with CRKP bloodstream infection. The ROC curve showed that the AUCs for evaluating the prognosis of preterm infants with NEC and purulent meningitis were 0.784 and 0.711, respectively. The AUC for evaluating the prognosis of preterm infants with a maximum VIS ≥52.5 points within 48 hours of onset was 0.840, and the AUC for combining the three factors was 0.931. Compared with NEC and purulent meningitis, the AUC for combining factors was higher, the differences were statistically significant ( P=0.002, P<0.001). Conclusions:Preterm infants with CRKP bloodstream infection who have a maximum VIS ≥52.5 points within 48 hours of onset, with NEC and purulent meningitis have a higher risk of death.

Objective:To investigate the Helicobacter pylori ( H. pylori) infection of Tibetan families and individuals in the Western Sichuan Plateau region and explore the related factors which affected H. pylori infection. Methods:This was a single-center cross-sectional study. Questionnaires were collected from 50 Tibetan families including 155 individuals in Western Sichuan Plateau region during March to May 2023. The 13C-urea breath test was performed to confirm the current infection status of participants. Binary logistic regression were used to analyze the related factors associated with H. pylori infection. Results:Among the 50 Tibetan households, the individual-based H. pylori infection rate was 47.10%(73/155), with two out of nine children and 48.63%(71/146) adults infected. The age group of 18 to 40 years had the highest infection rate (55.00%, 11/20). The prevalence of infection based on family was 80.00%(40/50), of which 16.00%(8/50) had all family members infected. Of the 59 couples surveyed, 23.73%(14/59) were both infected, and 45.76%(27/59) had one person infected. Of the six families which had children and adolescents, two households had their children infected. Logistic regression analysis showed that size of the family was a factor related to H. pylori infection (odds ratio=3.038, 95% confidence interval 1.043 to 10.491, P=0.042). Conclusions:The family-based H. pylori infection rate is relatively high in Tibetan residents in the Western Sichuan Plateau, and larger family size is related with higher risk of H. pylori infection within the family.

Objective:To explore the early differential diagnosis method by comparing the clinical characteristics of acquired immunodeficiency syndrome (AIDS) patients complicated with tuberculous meningitis (TBM) and cryptococcus neoformans meningitis (CNM).Methods:The AIDS patients admitted to Guangzhou Eighth People′s Hospital, Guangzhou Medical University from January 2011 to February 2022 and diagnosed with combined TBM and CNM after discharge respectively were included. A retrospective study was performed to analyze the clinical features of 21 AIDS patients complicated with TBM (TBM group) and 54 AIDS patients with CNM (CNM group) (all cases were confirmed by etiology). The data of meningitis-related symptoms and signs, blood routine test, CD4 + T lymphocyte counts, imaging characteristics and cerebrospinal fluid examination at admission were collected and analyzed. Statistical analysis was performed by using independent sample t test, rank sum test or chi-square test. Results:The age of patients in the TBM group was (44.6±12.9) years old, which was older than that of patients in the CNM ((37.6±12.6) years old), the difference was statistically significant ( t=-2.15, P=0.035). Forty-eight cases (88.89%) and seven cases (12.96%) in the CNM group experienced headaches and consciousness disorders respectively, with statistically significant differences compared to those in the TBM group (13 cases (61.90%) and nine cases (42.86%), respectively) ( χ2=7.25, P=0.007 and χ2=8.05, P=0.005, respectively). The proportion of leukopenia was 27.78%(15/54), and proportion of thrombocytopenia was 16.67%(9/54) in the CNM group, which were higher than those in the TBM group (4.76%(1/21) and 0(0/21), respectively), and the differences were statistically significant ( χ2=4.77, P=0.029 and χ2=3.98, P=0.042, respectively). The CD4 + T lymphocyte count in the TBM group was 74.0(92.0)/μL, which was higher than 19.5(56.5)/μL in the CNM group, and the difference was statistically significant ( Z=-2.87, P=0.009). The CNM group had 46 cases (85.19%) with cerebrospinal fluid pressure >180 mmH 2O(1 mmH 2O=0.009 8 kPa) and 24 cases (44.44%) with cerebrospinal fluid pressure >330 mmH 2O, which were significantly higher than those in the TBM group with seven cases (33.33%) and four cases (19.05%), respectively, and the differences were statistically significant ( χ2=19.61, P<0.001 and χ2=4.17, P=0.041, respectively). Fifty-two point three eight percent (11/21) of patients in the TBM group had a white blood cell counts>200×10 6/L in the cerebrospinal fluid, which was higher than that in the CNM group (1.85%(1/54)), with a statistically significant difference ( χ2=27.23, P<0.001). The white blood cell counts, protein and adenosine deaminase levels in the cerebrospinal fluid of TBM group were significantly higher than those in the CNM group (200.00(579.50)×10 6/L vs 17.50(66.25)×10 6/L, 1 863(2 858) mg/L vs 672 (513) mg/L and 6.60 (8.55) U/L vs 1.95(2.60) U/L, respectively), and the cerebrospinal fluid chloride level was lower than that in the CNM group ((107.71±8.22) mmol/L vs (115.99±6.55) mmol/L), and all the differences were statistically significant ( Z=4.11, P<0.001, Z=21.23, P=0.008, Z=2.09, P=0.040 and t=4.57, P<0.001, respectively). There was no significant difference in cerebrospinal fluid glucose between the TBM group and the CNM group ((1.86±1.22) mmol/L vs (2.34±1.05) mmol/L, t=-1.72, P=0.090). The proportion of patients with bilateral lung lesions in the TBM group was higher than that in the CNM group, and the difference was statistically significant (100.00%(21/21) vs 40.74% (22/54), χ2=-6.53, P=0.011). Conclusions:Patients with AIDS complicated with TBM are more likely to have consciousness disorders, inflammatory response in the cerebrospinal fluid, and more bilateral lung lesions. In contrast, patients with AIDS complicated with CNM are more frequently to experience severe headache and significant elevation of cerebrospinal fluid pressure, leukopenia and thrombocytopenia, and lower peripheral blood CD4 + T lymphocyte counts.

Objective:To understand the pathogen distributions of community-acquired pneumonia (CAP) in children, and to provide evidence for clinical diagnosis and treatment.Methods:The hospitalized children with CAP in Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine from January to December 2022 were selected as the research subjects. They were divided into infant group (28 d to less than one year), toddler group (one year to less than three years), preschool age group (three years to less than six years), and school age group (not less than six years) by age. According to the onset season, they were divided into spring group (February to April), summer group (May to July), autumn group (August to October), and winter group (January, November to December). Deep airway sputum samples were collected from all patients for bacterial culture identification. Respiratory viruses (influenza A virus (IVA), influenza B virus (IVB), respiratory syncytial virus (RSV), adenovirus, parainfluenza virus type 1 (PIV1), parainfluenza virus type 2 (PIV2), parainfluenza virus type 3 (PIV3)) were detected using direct immunofluorescence assay. Mycoplasma pneumoniae (MP) DNA was detected using fluorescent quantitative polymerase chain reaction, and particle agglutination was used to detect serum MP antibodies. Statistical analysis was performed using the chi-square test. Results:Among the 397 cases of CAP in children, pathogens were detected in 269 cases, with a positivity rate of 67.8%. A total of 309 pathogens were identified, including 204 strains of MP (66.0%), 60 strains of bacteria (19.4%), 42 strains of viruses (13.6%), and three strains of fungi (1.0%). Staphylococcus aureus (19 strains), Haemophilus influenzae (15 strains) and Streptococcus pneumoniae (five strains) were the predominant bacteria, while RSV (19 strains) and PIV3 (nine strains) were the main viruses. The distribution rates of MP, bacteria, and viruses showed statistically significant differences among different age groups ( χ2=99.82, 24.71 and 17.40, respectively, all P<0.05). MP infection was mainly observed in the preschool age group and school age group, and bacterial infection predominantly occurred in the infant group, and viral infection was most common in the toddler group. Among virus infected patients, RSV was detected in the toddler group and the preschool age group, while three cases of PIV3 cases were found in children over five years old. The distribution differences of MP, bacterial and viral infections between different seasons were statistically significant ( χ2=141.65, 20.44 and 31.87, respectively, all P<0.001), with a higher prevalence in winter. RSV infections demonstrated a clear seasonal trend, with 16 cases of RSV infections occurring in winter and spring. Conclusions:MP is the most frequently detected pathogen in children with CAP. Bacterial infection is the most common pathogen in infants with CAP. RSV is the most common viral pathogen, with infections concentrated in the toddler group and the preschool age group, and prevalence in winter and spring. Attention should be paid to PIV3 pneumonia in children over five years old. Rational drug use should be based on the pathogen spectrum characteristics of different seasons and age groups before selecting empirical treatment combinations.