OBJECTIVE To explore the clinical distribution and drug resistance of common species of pathogens iso-lated from a three-A hospital of Guangzhou from Jan.2017 to 2023 Dec.so as to provide bases for clinical diagno-sis and reasonable use of antibiotics.METHODS A total of 10,086 strains of aerobic bacteria were clinically isola-ted from the patients who were hospitalized in a three-A hospital of Guangzhou from 2017 to 2023.The constituent ratios of the common species of pathogens,specimen sources,distribution of departments and drug resistance rates to commonly used antibiotics were retrospectively analyzed.RESULTS Totally 10,086 strains of pathogens were isolated from the specimens of the hospitalized patients from 2017 to 2023.Klebsiella pneumoniae,Pseudo-monas aeruginosa,Escherichia coli,Acinetobacter baumannii and Staphylococcus aureus ranked the top 5 species of pathogens.The sputum,midstream urine and whole blood were the major specimen sources.The hospital-asso-ciated infection was highly prevalent in critical care medicine department,neurology department,geriatrics depart-ment,neurosurgery department and urology department.The result of drug resistance showed that the drug re-sistance rates of the K.pneumoniae and P.aeruginosa strains to various types of antibiotics showed upward trends(P＜0.05);the drug resistance rate of the A.baumannii strains to imipenem was decreased,while the drug resist-ance rates to most of the antibiotics were more than 45％.No gram-positive cocci strains that were resistant to vancomycin,teicoplanin or linezolid were found.CONCLUSIONS The common clinical isolates of pathogens are generally resistant to antibiotics.It is necessary for clinicians to attach great importance to the culture of pathogens and drug susceptibility testing and reasonably use antibiotics based on the result of drug susceptibility testing so as to reduce the occurrence and spread of drug-resistant strains.The hospital should strengthen the surveillance of drug resistance of bacteria so as to boost the clinical curative effect,standardize the management and use of antibi-otics and take effective measures to control of the hospital-associated infection.

OBJECTIVE To explore the clinical distribution and drug resistance of common species of pathogens iso-lated from a three-A hospital of Guangzhou from Jan.2017 to 2023 Dec.so as to provide bases for clinical diagno-sis and reasonable use of antibiotics.METHODS A total of 10,086 strains of aerobic bacteria were clinically isola-ted from the patients who were hospitalized in a three-A hospital of Guangzhou from 2017 to 2023.The constituent ratios of the common species of pathogens,specimen sources,distribution of departments and drug resistance rates to commonly used antibiotics were retrospectively analyzed.RESULTS Totally 10,086 strains of pathogens were isolated from the specimens of the hospitalized patients from 2017 to 2023.Klebsiella pneumoniae,Pseudo-monas aeruginosa,Escherichia coli,Acinetobacter baumannii and Staphylococcus aureus ranked the top 5 species of pathogens.The sputum,midstream urine and whole blood were the major specimen sources.The hospital-asso-ciated infection was highly prevalent in critical care medicine department,neurology department,geriatrics depart-ment,neurosurgery department and urology department.The result of drug resistance showed that the drug re-sistance rates of the K.pneumoniae and P.aeruginosa strains to various types of antibiotics showed upward trends(P＜0.05);the drug resistance rate of the A.baumannii strains to imipenem was decreased,while the drug resist-ance rates to most of the antibiotics were more than 45％.No gram-positive cocci strains that were resistant to vancomycin,teicoplanin or linezolid were found.CONCLUSIONS The common clinical isolates of pathogens are generally resistant to antibiotics.It is necessary for clinicians to attach great importance to the culture of pathogens and drug susceptibility testing and reasonably use antibiotics based on the result of drug susceptibility testing so as to reduce the occurrence and spread of drug-resistant strains.The hospital should strengthen the surveillance of drug resistance of bacteria so as to boost the clinical curative effect,standardize the management and use of antibi-otics and take effective measures to control of the hospital-associated infection.

To prepare polyclonal antibodies (PcAb) against UspA1 of Moraxella catarrhalis (Mc), we used bioinformatic analysis to determine the surface exposed region in this protein that holds the antigen epitopes. Then the corresponding coding sequences for this fragment was artificially synthesized according to the codon usage of Escherichia coli. The gene fragment was then subcloned into the prokaryotic expression vector pET-28a(+) and expressed in E. coli rosseta (DE3), and then the recombinant UspA1-His proteins were purified. Two New Zealand white rabbits were immunized with this protein to prepare antiserum. The resulting PcAb was then purified from the antiserum with Protein A affinity column. The results of fluorescence antibody assay, enzyme linked immunosorbent assay and Western blotting analysis showed that the PcAb could specifically recognize the surface exposed region of UspA1 on Mc. The preparation of the PcAb laid a foundation of further development of rapid detection technique for M. catarrhalis.

Objective To investigate the influencing factors involved in the establishment of a C57BL/6 J model of metastatic melanoma in the lung,including the way of tumor inoculation,the number of inoculated cells and the time of tumor formation. Methods Mouse melanoma B16F10 cells were cultured in vitro. 1)Eighteen healthy male C57BL/6 J mice were randomly divided into three groups. Mice in each group received 100 μL cell suspension(including 3 ×106 melanoma cells)via intravenous,intraperitoneal and subcutaneous injection,respectively. After two weeks,the mice were killed and dissected,and the tumor growth and metastasis were observed. 2)Eighteen male mice were randomly divided into three groups. Mice in each group were injected with 3 ×106cells,1 ×106cells, and 3 ×105cells through the tail vein,respectively. After two weeks,mice were killed and dissected,and the tumor growth and metastasis were observed. 3)Eighteen male mice were randomly divided into three groups. Mice in each group were injected with 1×106cells though the tail vein. Mice were killed and dissected after one week, two weeks and three weeks, respectively. The growth and metastasis of tumor were observed. Results 1)The success rate of lung metastasis was 100% in the mice with intravenous injection,but not in mice receiving intraperitoneal injection and subcutaneous injection. 2)The size of metastatic melanoma nodules were moderate in mice inoculated by 1 ×106cells. The number of melanoma metastatic foci was too high in the mice inoculated with 3 ×106cells,but too low in the mice inoculated with 3 ×105cells. 3)Significant metastatic melanoma foci were observed in the mice killed and dissected after two weeks with no death. The number of melanoma foci in the lung was too high in the mice killed after three weeks,while was too low in the mice killed at one week after tumor cell inoculation. Conclusions Intravenous injection of 1×106mouse melanoma cells into C57BL/6 J mice and killed after two weeks is an optimal method for establishment of a mouse model of metastatic melanoma in the lung, and is worth of recommendation.

Objective: To establish primary immune thrombocytopenia (ITP) animal model induced by anti-platelet membrane glycoprotein GPⅠbα antibodies AN51 and R300. Methods: Twenty guinea pigs (6-8 week) were divided into 4 groups. Five guinea pigs in each group were intravenously injected with different doses of AN51 (0.05, 0.1, 0.2 μg/g) and 0.2 μg/g IgG as control. The whole blood was collected from inner angular venous plexus. Platelets number was determined by an automated cell counter and Swiss-Jim method. Then, the similar protocol was used to establish ITP nude mice model by intraperitoneal injection of different concentrations of anti-platelet GPⅠbα antibody R300, respectively. Results: ①Five minutes after intravenous injection of AN51 at 0.05, 0.1 and 0.2 μg/g, the platelet counts of guinea pigs reduced about 0-5%, 50%-60% and 70%-80% compared to the control group, respectively. The difference was statistically significant (P<0.01) . ②Six hours after intraperitoneal injection of R300 at 0.05, 0.1, 0.2 μg/g, the platelet counts of nude mice decreased about 20%-30%, 60%-70% and 80%-90% compared to the control group, respectively. The difference was statistically significant (P<0.01) . The nude mice, injected 0.2 μg/g R300 once a day for 2 weeks, showed typical ITP clinical manifestations including large number of petechiaes or ecchymoses on limbs, head and abdomen. Conclusion AN51 at 0.2 μg/g and R300 at 0.2 μg/g could establish stable ITP model in guinea pigs and nude mice respectively.

0.05). It is decrease greatly, than those in anti-VEGF control (P0.05).The toxicity of CRM9 control are markedly higher than those in blank control groups (P