Objective:To analyze the carriage status, subtype distribution and flanking gene sequence characteristics of oxacillinases (OXA enzyme) in 241 clinical strains of Pseudomonas aeruginosa, and assess their roles in the drug resistance of Pseudomonas aeruginosa and ability to horizontally transfer across species. Methods:Clinical P. aeruginosa isolates were collected from four hospitals in Sanya, Tangshan, Zhangjiakou, and Beijing. The prevalence of oxacillinases and their flanking gene sequences was analyzed by whole-genome sequencing (NGS) and bioinformatic approaches. Results:A total of 241 isolates of P. aeruginosa were gathered, and 35 blaOXA subtypes were identified through screening of 252 blaOXA genes. These genes were classified into three subfamilies: blaOXA-50-like (241, 95.6%), blaOXA-1-like (9, 3.6%) and blaOXA-10-like (2, 0.8%). Among these, 11 subtypes (11, 31.4%) were novel blaOXA subtypes. Nine of these belonged to the blaOXA-50-like subfamily and were designated as blaOXA-1244, blaOXA-1245, blaOXA-1246, blaOXA-1250, blaOXA-1252, blaOXA-1253, blaOXA-1254, blaOXA-1255, and blaOXA-1256. The remaining two belonged to the blaOXA-10-like subfamily and were named blaOXA-1247 and blaOXA-1248. Compared to the amino acid sequence of OXA-10, the newly identified subtype OXA-1247 exhibited a mutation at position 117, where a valine was replaced by a leucine. This change was thought to improve the enzyme′s ability to hydrolyze carbapenems. In the analysis of the flanking sequences of the blaOXA genes, Class I integrons were identified in four bacterial strains. The variable regions of these integrons carried three distinct patterns of resistance gene cassettes: aac( 6′) -Ib-blaOXA-1247-ant( 3′′) -Ia, aac( 6′) -Ib-blaOXA-1248 and aac( 6′) -Ib- blaIMP-45-blaOXA-1-catB3. Among these, the strain BJ2326 carried a class I integron that was connected to the downstream IS CR1 element to form a composite class I integron structure, additionally carrying the resistance gene blaPER-1. Out of the 223 non-wild-type P. aeruginosa strains, 127 strains exhibited non-wild-type profiles to the four beta-lactam antibiotics MEM, CAZ, FEP, and TZP, with the combination of MEM+CAZ+FEP being the most prevalent, representing 57.0% of the total. Conclusions:The blaOXA genes in 241 clinical P. aeruginosa strains showed diversity. Some blaOXA genes had a co-transfer risk with the metallo-β-lactamase resistance gene blaIMP-45. Among the 11 newly discovered blaOXA subtypes, the new subtype OXA-1247 may have carbapenemase activity and potential for horizontal transfer.

Objective:To analyze the carriage status, subtype distribution and flanking gene sequence characteristics of oxacillinases (OXA enzyme) in 241 clinical strains of Pseudomonas aeruginosa, and assess their roles in the drug resistance of Pseudomonas aeruginosa and ability to horizontally transfer across species. Methods:Clinical P. aeruginosa isolates were collected from four hospitals in Sanya, Tangshan, Zhangjiakou, and Beijing. The prevalence of oxacillinases and their flanking gene sequences was analyzed by whole-genome sequencing (NGS) and bioinformatic approaches. Results:A total of 241 isolates of P. aeruginosa were gathered, and 35 blaOXA subtypes were identified through screening of 252 blaOXA genes. These genes were classified into three subfamilies: blaOXA-50-like (241, 95.6%), blaOXA-1-like (9, 3.6%) and blaOXA-10-like (2, 0.8%). Among these, 11 subtypes (11, 31.4%) were novel blaOXA subtypes. Nine of these belonged to the blaOXA-50-like subfamily and were designated as blaOXA-1244, blaOXA-1245, blaOXA-1246, blaOXA-1250, blaOXA-1252, blaOXA-1253, blaOXA-1254, blaOXA-1255, and blaOXA-1256. The remaining two belonged to the blaOXA-10-like subfamily and were named blaOXA-1247 and blaOXA-1248. Compared to the amino acid sequence of OXA-10, the newly identified subtype OXA-1247 exhibited a mutation at position 117, where a valine was replaced by a leucine. This change was thought to improve the enzyme′s ability to hydrolyze carbapenems. In the analysis of the flanking sequences of the blaOXA genes, Class I integrons were identified in four bacterial strains. The variable regions of these integrons carried three distinct patterns of resistance gene cassettes: aac( 6′) -Ib-blaOXA-1247-ant( 3′′) -Ia, aac( 6′) -Ib-blaOXA-1248 and aac( 6′) -Ib- blaIMP-45-blaOXA-1-catB3. Among these, the strain BJ2326 carried a class I integron that was connected to the downstream IS CR1 element to form a composite class I integron structure, additionally carrying the resistance gene blaPER-1. Out of the 223 non-wild-type P. aeruginosa strains, 127 strains exhibited non-wild-type profiles to the four beta-lactam antibiotics MEM, CAZ, FEP, and TZP, with the combination of MEM+CAZ+FEP being the most prevalent, representing 57.0% of the total. Conclusions:The blaOXA genes in 241 clinical P. aeruginosa strains showed diversity. Some blaOXA genes had a co-transfer risk with the metallo-β-lactamase resistance gene blaIMP-45. Among the 11 newly discovered blaOXA subtypes, the new subtype OXA-1247 may have carbapenemase activity and potential for horizontal transfer.

BACKGROUND/OBJECTIVES: The study examined the association between homocysteine and diabetes mellitus in patients with H-type hypertension and assessed the possible effect modifiers. SUBJECTS/METHODS: This cross-sectional study included 1,255 eligible participants in the ‘H-type Hypertension Management and Stroke Prevention Strategic International Science and Technology Innovation Cooperation Project’ among rural Chinese people with H-type hypertension. A multivariate logistic regression model was used to evaluate the relationship between homocysteine and diabetes mellitus. RESULTS: The mean level of total homocysteine (tHcy) in the diabetes mellitus population was 19.37 μmol/L, which was significantly higher than the non-diabetic patients (18.18 μmol/L). When tHcy was analyzed as a continuous variable, the odds ratio (OR) of diabetes was 1.17 (95% confidence interval [CI], 1.01–1.35; per interquartile range). When tHcy was stratified according to the quintile, the ORs for diabetes were 2.86 (95% CI, 1.22–6.69) in the highest quintile (tHcy ≥ 20.60 μmol/L) compared to the reference group (tHcy < 12.04 μmol/L). When tHcy was grouped by 15 μmol/L and 20 μmol/L, patients with tHcy ≥ 20 μmol/L had a significantly (P = 0.037) higher risk of diabetes (OR, 2.03; 95% CI, 1.04–3.96) than in those with tHcy < 15 μmol/L. Subgroup analysis showed that the tHcy-diabetes association was unaffected by other variables. CONCLUSION In this study of rural Chinese people with H-type hypertension, the tHcy levels showed a positive association with diabetes mellitus. This independent association is unaffected by other potential risk factors.

Standardized Residency Training (SRT) in China is gradually maturing. To standardize the training quality in each training base, corresponding standards have been published with regular revisions to various indicators. However, some training bases and professional bases still face challenges such as inadequate awareness of qualified teaching resources, lack of precise regulations, and absence of standardized process assessment. Through years of cumulative in-depth interpretation of various assessment indicators and innovations based on the characteristics of laboratory medicine residents, the clinical laboratory base in Cancer Hospital, Chinese Academy of Medical Sciences is continuously improving the quality of teaching staff through a multi-level teacher qualification training mode and a strict assessment mechanism. Meanwhile, a comprehensive and effective training system has been established to ensure the smooth implementation of SRT tasks. In addition, a diversified lecture system and a standardized progressive assessment process have been established to enhance the overall clinical abilities of residents.

Objective To describe a case of lower limbs infection of Helcococcus Kunzii in North China University of Science and Technology Affiliated Hospital in October 2017 and to analyze the etiology and drug susceptibility??Methods The bacteria were identified by French Meriere mass spectrometer and BD Phoenix?100 automatic bacterial identification／drug sensitivity system??The drug resistance of the bacteria was detected by disk diffusion method,and collected the clinical information and related literature information of the Helcococcus Kunzi to analyze??Results The Gram?positive cocci was isolated from the foot secretion of a patient with venous thrombosis of lower limbs complicated with infection??The result of smear was Gram?positive cocci in double,agglomerate and varied in size??On the blood plate,there was a small colony of α hemolysis??Thixozyme negative,β galactosidase negative??The results of mass spectrometry identification and two kinds of fully automatic bacterial identification ／ drug sensitivity system were identified as Helcococcus Kunzii,the isolates was resistant to erythromycin and clindamycin among the 10 antibiotics tested??By searching,sorting out and analyzing the literature information, it is revealed that the infection of this bacterium is not related to sex??Middle?aged and elderly people are mostly infected??And the cocci easily infected patients with lower immunity??The infection of lower limbs is 47??37%,the infection of blood flow is 15??79% and the other ways of infection are 42??11%( lung, mammary gland, etc??)??Conclusion Helcococcus Kunzii is a conditional pathogen, and patients with lower immunity are more common??Erythromycin resistance could identify it from the green balloon bacteria??Moreover, the bacteria could cause a wide spectrum of diseases,and easily cause sepsis and lower limbs infections,which reminds us that we should be vigilant in clinical practice??

Objective To investigate the clinical significance of biochemical markers in EBC and serum in patients with bronchial asthma and chronic obstructive pulmonary disease overlap syndrome(ACOS). Methods We selected Patients with chronic airway inflammatory diseases in our hospital,These patients underwent clinical trial after the stable phase,including 18 ACOS patients,22 asthma patients,24 COPD patients and 20 healthy non-smokers in the same period.8-isoPG and other inflammatory factors levels in EBC and serum were measured in the selected patients. A comparative analysis was performed. Results The levels of EBC 8-isoPG in the ACOS group were significantly higher than those in the healthy control group,The levels of serum and EBC 8-isoPG in the ACOS group were significantly higher than the asthma group and the COPD group(P < 0.05). The level of 8-isoPG in EBC was not related to age,smoking index,weight,and FEV1value(P>0.05).Conclusions Inflam-matory factors including 8-isoPG,are involved in chronic inflammation in lung tissues of patients with ACOS. 8-isoPG in EBC may have potential value in identifying ACOS from COPD and asthma as biomarkers and deserve further study.

Objective To study the protective effect of ROP2 nuclei acid vaccine in mice.Methods Forty-two BALB/c mice were divided into three groups.Each mouse in experiment group was injected with 50 ?g recombinant plasmid pc-DNA3-ROP2 through musculus quadriceps fexoris.In control groups,each mouse was injected with 50 ?g blank plasmid pc-DNA3 and with 50 ?l PBS respectively.All mice were immunized for three times with an interval of three weeks.The volume was doubled for the final injection in the two plasmid groups.Blood,spleens and lymph nodes of 4 mice in each group were taken for the detection of CD4+,CD8+ T cells and cytokines 2 weeks after the final immunization.The rest mice in 3 groups were challenged with 500 tachyzoites of Toxoplasm gondii RH strain for further observation.Results The vaccine induced strong cellular and humoral immune response.The titer of antibody in serum was high after inoculation and recognized ROP2 protein antigen expressed in vitro.The lymphocyte phenotype was analyzed.CD4+ T cells proliferated sharply(69.5?3.4)%,and the ratio of CD4+/CD8+ increased considerably by(4.69?1.32)%(P

AIM: To construct a high-level expression system of recombinant human neuronal nitric oxide synthase (hnNOS) full-length enzyme in Escherichia coli. METHODS: The coding sequence of hnNOS full-length was firstly amplified by PCR, and then ligated into the expression vector pCWori+. The recombinant plasmid was transformed into Escherichia coli BL21 for high-level expression. After having been checked with Western blot, the enzyme was used for large-scale culture and purification. Finally, the property of the enzyme was determined by spectrophotometric method. RESULTS: The constructed expression system could give a yielding of 3 mg/L initial culture. CONCLUSION: The expression system constructed is fully sufficient to express the active human neuronal nitric oxide synthase.