Abstract: Objective To investigate the clinical features and risk factors for severe tsutsugamushi disease, so as to provide reference for diagnosis and differentiation of severe tsutsugamushi disease as soon as possible. Methods The clinical data of 178 cases of inpatients with tsutsugamushi disease admitted to the Guangzhou Eighth People's Hospital, Guangzhou Medical University from January 2016 to September 2021 were collected and analyzed according to their gender, age, underlying diseases, clinical characteristics at admission, laboratory examination results within 24 hours of admission and epidemiological history. The patients were divided into the severe group and the non-severe group according to the diagnostic criteria. The data of clinical characteristics, laboratory examination and prognosis of the two groups were compared. Multivariate logistic regression analysis was performed on the variables with statistical significance and the receiver operating characteristic curve (ROC) was drawn. Results A total of 178 patients were included in this study, with 37 in the severe group and 141 in the non-severe group. Compared with the non-severe group, the age of the severe group was older, the underlying diseases were more, the incidence of dyspnea and the levels of white blood cell, total bilirubin, aspartate aminotransferase, lactate dehydrogenase, cystatin C, uric acid and serum creatinine were significantly increased, the levels of platelet and albumin were significantly decreased (all P<0.05). The dyspnea [odds ratio (OR value)=8.93, 95% confidence interval (CI): 1.200-66.424; P=0.032], total bilirubin (OR=1.091, 95%CI: 1.028-1.159; P=0.004) and serum creatinine (OR=1.052, 95%CI: 1.004-1.102; P=0.033) were independent risk factors for severe tsutsugamushi disease. The area under ROC curve of total bilirubin and serum creatinine were 0.777 and 0.764, respectively (both P<0.01), indicating high predictive value for severe tsutsugamushi disease. The optimal cut-off value for total bilirubin was 23.01 µmol/L, with a sensitivity of 54.10% and a specificity of 90.60%; the optimal cut-off value for creatinine was 126.45 µmol/L, with a sensitivity of 43.20% and a specificity of 100.00%. The case fatality rate of severe tsutsugamushi disease was 2.70%. Conclusions The patients with severe tsutsugamushi disease are older, and have more underlying diseases. Dyspnea, increased total bilirubin and elevated serum creatinine are independent risk factors for severe tsutsugamushi disease, which can help in the early identification of severe tsutsugamushi disease early.

Abstract: Objective　To investigate the antimicrobial activity of omadacycline (OMC) against clinical Streptococcus agalactiae (GBS) isolates, as well as its relationship with biofilm formation, resistance genes and virulence genes. Methods　A total of 136 strains of Streptococcus agalactiae isolated from Shenzhen Nanshan People's Hospital between 2015 to 2020. The minimum inhibitory concentration (MIC) of OMC against Streptococcus agalactiae was determined by broth microdilution. Crystal violet staining was used to detect the biofilm formation ability of GBS. Resistance genes (tetM, tetO, tetK, ermB, OptrA) and virulence genes (cpsⅢ, bca, fbsA, cpsA, scpB) were investigated by polymerase chain reaction (PCR). Results　Among the 136 clinical isolates of GBS, 20 strains (14.7%) were resistant to OMC, 64 (47.1%) were intermediate, and 52 (38.2%) were sensitive. Fifty-seven strains (41.9%) were biofilm-positive, 20 of which (35.1%) were sensitive to OMC. Seventy-nine strains (58.1%) were biofilm-negative, 32 of which (40.5%) were susceptible to OMC. There was a statistically significant difference in the sensitivity rates between the two groups of strains (χ2=63.062, P<0.001), but there was no significant difference in the sensitivity of OMC among the biofilm-positive strains (Fisher's exact test, P=0.824). The resistance rates of tetM, tetO, ermB and OptrA positive strains were higher than those of negative strains, while tetK was opposite. The presence of tetM (Z=0.815, P=0.415), tetO (Z=0.151, P=0.88), tetK (Z=0.567, P=0.571), ermB (Z=1.198, P=0.231) resistance genes in Streptococcus agalactiae had no significant impact on the sensitivity of OMC. However, the presence of the OptrA resistance gene showed a statistically significant effect on the sensitivity of OMC (Z=2.913, P=0.004). The virulence factors cpsⅢ, bca, fbsA, cpsA and scpB were all detected at a rate higher than 50%. The presence of the virulence genes cpsⅢ (Z=0.222, P=0.824), bca (Z=0.141, P=0.888), fbsA (Z=0.813, P=0.416), and cpsA (Z=1.615, P=0.106) in Streptococcus agalactiae had no significant impact on the sensitivity of OMC. However, there was a significant inter-group difference in the scpB virulence gene (Z=2.844, P=0.004), but the rank mean values and resistance rates of scpB-positive strains were lower than those of the negative strains. Conclusions　The formation of biofilm in Streptococcus agalactiae reduces its sensitivity to OMC, but there was no significant difference in the sensitivity to OMC among the biofilm-positive strains. The presence of resistance genes tetM, tetO, tetK, ermB, and virulence genes cpsⅢ, bca, fbsA, cpsA, scpB in Streptococcus agalactiae is not associated with OMC resistance, but the presence of the resistance gene OptrA is correlated with OMC resistance..

Abstract: Objective　To establish a risk prediction model for nosocomial infection in preterm very low birth weight infants, and conduct internal validation. Methods　A total of 206 cases of very low birth weight premature infants hospitalized in the Department of Neonatology of Union Hospital Affiliated to Tongji Medical College from January 2018 to June 2020 were included in this study, factors that may affect the nosocomial infection of children were collected, and the infants were divided into two groups according to whether there is nosocomial infection. The influencing factors were compared between the two groups, and multivariate Logistic regression analysis was performed after screening variables with LASSO regression. According to the results of multi factor analysis, the nomogram model was constructed and verified internally. Results　A total of 29 of 206 children had nosocomial infection (14.08%), and 33 pathogenic bacteria were detected, including 23 Gram-negative bacteria, 9 Gram-positive bacteria and 1 fungus. The results of multivariate logistic regression analysis based on LASSO regression showed that the risk factors for nosocomial infection of VLBW premature infants were 28-31+6 weeks of gestation, amniotic fluid pollution, mechanical ventilation, indwelling gastric tube, unreasonable use of antibiotics, and hospitalization time ≥ 7 days. The protective factors were Apgar score ≥ 7 points at 1 min and breast feeding accounting for 50% or more (P<0.05). The Area Under Curve (AUC) of ROC curve of nomogram model was 0.946 [95%CI(0.923, 1.000)]. The calibration curve showed that the probability of hospital infection predicted by the model was basically consistent with the actual probability. The decision curve showed that when the probability threshold of nomogram model to predict the risk of nosocomial infection of very low birth weight premature infants was 0-0.85, the net rate of return was greater than 0. Conclusion　Preterm infants with extremely low birth weight are at high risk of nosocomial infection, mainly affected by factors such as gestational weeks, hospitalization time, amniotic fluid pollution, etc. The nomogram model constructed by the above factors has high accuracy and discrimination for predicting nosocomial infection in such children.

Abstract: Objective　In order to understand and master the prevalence of different genotypes and the rate of different drug-resistant Mycobacterium tuberculosis genotypes in Hainan Province, 136 drug-resistant Mycobacterium tuberculosis strains collected in Hainan province in 2022 were genotyped, and to provide scientific basis for tuberculosis prevention and control strategy in Hainan Province. Methods　A total of 136 drug-resistant Mycobacterium tuberculosis strains were collected in Hainan Province. The clinical isolates were genotyped using the Spoligotyping technique, and the drug resistance rates of different genotypes of Mycobacterium tuberculosis were statistically analyzed. Results　Among the 136 strains of drug-resistant Mycobacterium tuberculosis, 54.41% (74/136) belonged to the Beijing types, 27.94% (38/136) to non-Beijing types and newly identified genotypes accounted for 17.65% (24/136). The Beijing type included two genotypes, SIT1 and SIT269 genotypes, accounting for 52.94% (72/136) and 1.47% (2/136) respectively. Among the non-Beijing genotypes, the T type (T1, T2, T3) accounted for 21.32% (29/136), the U type accounted for 6.62% (9/136). Clustering analysis of genotyping results revealed two major clusters, Beijing type and non-Beijing type, as well as several scattered novel genotypes. Clustering analysis of Spoligotyping results classified the 136 drug-resistant strains into 3 clusters, with a clustering rate of 75.74% (103/136). The rates of mono-resistance (MR), poly-resistance (PR), multi-drug resistance (MDR), and other types of drug resistance in Beijing type and non-Beijing type were 41.89% (31/74), 13.51% (10/74), 24.33% (18/74), 20.27% (15/74) and 36.84% (14/38), 15.79% (6/38), 26.32% (10/38), 21.05% (8/38) respectively. Chi-square test results showed no statistically significant differences in drug resistance rates between the Beijing and non-Beijing types (P>0.05). Conclusion　The genotype of Mycobacterium tuberculosis in Hainan Province showed genetic polymorphism, with the main epidemic genotype being SIT1 in the Beijing type. Monitoring of Mycobacterium tuberculosis in this genotype should be strengthened.

Abstract: Objective To analyze the correlation between the thromboelastography (TEG) indexes and the indexes related to liver injury in patients with heat stroke, and explore the diagnostic value of TEG indexes for liver injury in patients with heat stroke. Methods A total of 95 patients with exertional heat stroke (EHS) admitted to 924 Hospital of the Joint Service Support Force of the People's Liberation Army of China from August 2020 to July 22 were selected, and divided into a non-liver injury group (55 cases) and a liver injury group (40 cases) according to whether there was liver injury. TEG instrument was used for the detection of thromboelastography to record the TEG parameters, including reaction time (R), agglutination time (K), α angle, maximum amplitude (MA value), and coagulation complex index (CI). The levels of glutamic transaminase (AST), alanine aminotransferase (ALT), total bilirubin (TBil), albumin (ALB) were detected by automatic biochemical analyzer. Pearson's method was applied to analyze the correlation between thromboelastography indexes R, K, α angle, CI and liver function indexes AST, ALT, TBil, ALB in patients with heat stroke after liver injury. Receiver operating characteristic curve (ROC) was applied to analyze the predictive value of thromboelastography indexes R, K, α angle, CI and combined detection for liver injury in patients with heat stroke. Results Compared with the non-liver injury group, the AST, ALT and TBil levels in patients with heat stroke in the liver injury group were higher (t=26.174, 16.923, 18.414, P<0.05), while the ALB level was lower (t=24.596, P<0.05); compared with the non-liver injury group, the R and K of patients with heat stroke in the liver injury group were higher (t=58.014, 52.862, P<0.05), and the α angle and CI were lower (t=46.853, 60.717, P<0.05); R was positively correlated with AST and ALT (r=0.532, 0.610, P<0.001), and negatively correlated with ALB (r=-0.551, P<0.001) in patients with heat stroke complicated with liver injury; K was positively correlated with AST, ALT and TBil (r=0.661, 0.531, 0.504, P<0.001); α angle was negatively correlated with AST and ALT (r=-0.473, -0.448, P<0.01), and positively correlated with ALB (r=0.539, P<0.001); CI was negatively correlated with AST, ALT and TBil (r=-0.458, -0.505, -0.549, P<0.001); the area under the curve (AUC) of thromboelastography indexes R, K, α angle and CI in predicting liver injury in patients with heat stroke was 0.807 (sensitivity of 70.0%, specificity of 81.6%), 0.831 (sensitivity of 77.5%, specificity of 85.5%), 0.747 (sensitivity of 67.5%, specificity of 74.5%), and 0.788 (sensitivity of 77.5%, specificity of 83.6%), respectively. The AUC of combined detection to predict liver injury in patients with heat stroke was 0.967 (sensitivity of 92.5%, specificity of 91.9%). Conclusions The thromboelastography indexes are correlated with the indexes related to liver injury in patients with heat stroke, and the thromboelastography indexes are helpful to diagnose liver injury in patients with heat stroke.

Abstract: Objective　To investigate the molecular characteristics and drug resistance of Staphylococcus aureus (SA) isolated from wounds of paatients with orthopedic trauma, and analyze the molecular subtyping, virulence genes and drug resistance of SA in wounds of patients, so as to provide reference for the prevention and treatment of wound SA infection in patients. Methods　From January 2020 to June 2022, a total of 128 SA isolates were collected from wound specimens of orthopedic trauma patients at Wuxi 9th People's Hospital Affiliated to Soochow University. Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA) were differentiated using PCR. Multilocus Sequence Typing (MLST), staphylococcal protein A (spa), staphylococcal chromatoidal cassette mec (SCCmec), and accessory gene regulator (agr) typing were performed to determine the molecular typing and presence of virulence genes and drug resistance profiles. Results　Among the 128 SA isolates, 76 (59.38%) were MRSA and 52 (40.62%) were MSSA. MRSA typing showed that, MLST was dominated by ST59 (46 strains, 60.53%), spa was dominated by t437 (52.63%), SCCmec was dominated by Ⅰ (42.11%) and Ⅳ (39.47%). MSSA typing showed that, MLST was dominated by ST188 (30.77%), spa was dominated by t189 (61.54%), agr was dominated by Ⅰ (53.85%). In MLST typing, ST59 of MRSA was higher than that of MSSA, and ST188 and ST6 of MRSA were lower than those of MSSA (χ2=36.207, 20.227, 9.984, P<0.05). In spa typing, the t437 of MRSA was higher than that of MSSA, and the t189 of MRSA was lower than that of MSSA (χ2=18.276, 32.781, P<0.05). The virulence genes showed that, the detection rates of hlb and seb in MRSA were higher than those in MSSA (χ2=47.838, 10.261, P<0.05), and the detection rates of cna and ebpS in MRSA were lower than those in MSSA (χ2=26.176, 8.305, P<0.05). Drug susceptibility test showed that, and the drug resistance rates of MRSA and MSSA to vancomycin (VAN) and linezolid (LNZ) were 0. The drug resistance rates of MRSA to oxacillin (OXA), ERY and CLI were 86.84%, 68.42% and 76.32%, which were higher than corresponding 7.69%, 42.31% and 46.15% of MSSA (χ2=78.055, 8.623, 12.200, P<0.05). The analysis of multi-drug resistant strains (MDR) showed that 76 MRSA strains were MDR strains, and 12 of 52 MSSA strains (23.08%) were MDR strains. Conclusions　The molecular characteristics of SA isolated from orthopedic trauma patients' wounds were predominantly associated with MRSA strains of ST59-t437-SCCmec Ⅰ/Ⅳ-MRSA and ST188/ST6-t189-agr Ⅰ. These strains showed higher resistance to oxacillin, erythromycin, clindamycin, and higher susceptibility to vancomycin and linezolid. Such characteristics were closely related to the carriage of virulence genes. Clinicians should pay attention to the presence of MDR MSSA and develop appropriate antimicrobial strategies based on SA's molecular characteristics and antimicrobial resistance.

Abstract: Objective To explore the prevalence and bacterial strains of Francisella tularensis (F. tularensis) in wild rodents in Changbai Mountain area of China, and to further understand the epidemiological characteristics of F. tularensis infections in this area. Methods Wild rodents were captured from forest and forest-edge farmland from Kuandian County and Jianshi Forest District in the Changbai Mountain area, 2012-2014. DNA was extracted from the spleen tissues of the rodents, and the fopA gene of F. tularensis in wild rodents was detected using nested PCR. The infection rates were calculated for different areas and rat species. The bacterial subspecies of positive samples were identified using type-specific primers (C1/C4), and sequencing and comparative analysis were performed. Results A total of 133 wild rodents belonging to 6 rat species were captured. Among them, eight samples from three rat species (Apodemus agrarius, Apodemus peninsulae, Tscherskia triton ) were detected positive, with the overall positive rate of 6.01%. The positive rates of F. tularensis of Ji'an and Kuandian were 7.46% and 4.54%, respectively, and there was no difference in positive rates for different regions (χ2=0.117, P=0.732) and different rat species (χ2=0.641, P=0.986). The subspecies analysis showed that the detected 8 trains of F.tularensisall belonged to F.tularensis type B (F.subspecies subsp. holarctica). Genetic evolution analysis was performed on the fopA gene sequences of three positive samples (JA56, JA33, and JA38), which clustered together with Russia strains(CP009694.1, CP044004.1) and China strains (HM371344.1, HM371343.1) F.tularensis type B, with sequence similarities ranging from 99.21% to 99.47%. Conclusions Infection of F.tularensis subsp. holarctica existed in wild rodents in Changbai Mountain area of China, which suggests the existence of F.tularensis infection risks in this area.

Abstract: Objective To investigate the prevalence of C580Y mutation of kelch13 gene in the imported P. falciparum cases in Wuhan City, China, and to provide a reference basis for the prevention and treatment of imported falciparum malaria. Methods From 2009 to 2015, blood samples were collected from returnees who infected with P. falciparum in endemic areas of Africa and Southeast Asia in Wuhan City. The P. falciparum DNA was extracted from the blood samples, and kelch13 gene was amplified by loop-mediated isothermal amplification (LAMP), and the distribution of C580Y mutation was analyzed. Results C580Y mutation was detected in 16 of the 208 cases tested by LAMP. No mutations were detected in 69 cases of imported falciparum malaria from Africa during 2009-2012, while 13 cases of the C580Y mutation were detected in 114 cases from 2013 to 2015, with a mutation rate of 11.4%. The mutation rate in South Africa, West Africa, and Central Africa was 12.5%, 9.6%, and 19.0%, respectively, with no mutations detected in cases from North Africa and East Africa. Among the 25 cases of falciparum malaria from Southeast Asia between 2009 and 2013, three cases were positive for the C580Y mutation, all from Myanmar, with a mutation rate of 14.3% (3/21) in Myanmar and 12.0% (3/25) in Southeast Asia. There was no significant difference in the mutation rate between Africa and Southeast Asia after 2013 (P>0.05). Conclusions Our findings highlight the varying degrees of C580Y mutations of kelch13 gene in imported P. falciparum cases in Wuhan and suggest the need for enhanced monitoring and evaluation of related resistance genes.

Abstract: Bartter syndrome (BS) is a kind of inherited metabolic disease characterized by electrolyte and endocrine disorder, resulting from genetic gene mutation or deletion. Clinically, it manifests as vomiting, constipation, feeding difficulties, weight loss, growth retardation. The laboratory examination shows hypokalemia, metabolic alkalosis, hyperreninemia, aldosteronism, etc. As an autosomal recessive genetic disease, BS has an extremely low incidence rate, making diagnosis and treatment quite challenging. In recent years, with the progress of gene detection and other technologies, China has made great progress in the study of BS, more and more BS has been diagnosed accurately. According to known gene mutation types, it can be divided into type 1, type 2, type 3, type 4, type 5 and Gitelman syndrome, a total of 6 types, with type 4 further divided into type 4a and type 4b. At present, the most common type of children with BS in clinical practice is type 3, which is the classic type of BS. This paper reports a case of Bartter syndrome type 4b (BS4b). After two rounds of three-generation family gene sequencing, it was discovered that the infant had a combined mutation of both the CLCNKA and CLCNKB alleles, in addition to Alport syndrome, and both parents were carriers of this type of gene defect. The child was finally diagnosed as BS4b and Alport syndrome. This report, combined with the patient's clinical features, diagnosis and treatment process, as well as related literature analysis, aims to provide experience for understanding and diagnosis and treatment of this disease.

Abstract: Objective　To report a case of suppurative knee arthritis caused by Pasteurella multocida and review relevant literature to improve the awareness of the clinical physicians regarding this bacterium and provide reference for clinical diagnosis and treatment. Methods　A case of right knee suppurative arthritis caused by Pasteurella multocida was retrospectively reported and relevant literatures were reviewed in this article. Results　The infected person was a 76-year-old female patient with a 5-year history of intermittent pain in his right knee and suffered from joint swelling, aggravation pain, and limited flexion and extension activities after intraarticular injection of sodium hyaluronate. After admission and completing all necessary tests, the patient was later confirmed to have been infected with Pasteurella multocida. The patient's right knee was promptly examined and cleared under arthroscopic surgery, synovium and meniscus were excised, a drainage tube was inserted, and continuous joint cavity irrigation was performed after the surgery, and then ceftriaxone was injected and amoxicillin/clavulanate potassium was taken orally for anti-infection and the patient's condition improved significantly after 26 days. Conclusions　Pasteurella multocida infection cases are relatively rare, but the consequences in high-risk groups are relatively serious. Therefore, awareness of Pasteurella multocida and infection caused by it should be improved and high-risk groups should try to avoid contact with infectious sources as well as strengthen the management of pets so as to avoid infection.