ObjectiveTo describe the novel variants of the Smqnr family of quinolone resistance genes and their distribution in clinical isolates of Stenotrophomonas maltophilia, and investigate the relationship between Smqnr and quinolone resistance. MethodsThe identification of 442 strains of Stenotrophomonas maltophilia were performed by VITEK automated identification and susceptibility. Minimum inhibitoryconcentrationsof tigecycline,chloramphenicol,ceftazidime,compoundsulfamethoxazole,ticarcillin/clavulanic acid, levofloxacin and moxifloxacin against Stenotrophomonas maltophilia were detected by standard agar dilution method. Full length of Smqnr gene was amplified by polymerase chain reaction (PCR) and sequenced. DNAMAN software was used to compare the sequence divergence and construct the genealogical tree to analyze the phylogenetic relationships of Smqnr family. Results Stenotrophomonas maltophilia was resistant to the 7 kinds of clinical antibiotics in various extent ( from 5％ to 50％ ). Levofloxacin showed s good antibacterial activity with the resistance rate of 6. 11％ (27/442), nevertheless the best was moxifloxacin with the resistance rate of 5. 88％ (25/442). Smqnr gene was detected in 114 of 442 strains of Stenotrophomonas maltophilia[25.79％ (114/442)], including 11 known genes and 20 novel variants of the Smqnr genes ( Smqnr28-47 ) which was caused by several genes mutation changing the translation of 219 amino acids. The gene detection rate of resistant, intermediate and sensitive strains was 42. 30％ (11/26), 34. 37％ (11/32) and 23.95％ (92/384), respectively. The Smqnr gene harbored the highest detection rote (37. 78％ ) in the sensitive strains of Stenotrophomonas maltophilia with minimal inhibitory concentration of 0. 125 μg/ml. Conclusions The gene coding region of Smqnr is highly polymorphic and the novel variants of Smqnr gene are caused by several genes mutation changing the translation of 219 amino acids. Smqnr gene in Stenotrophomonas maltophilia has a high detection rate and different distribution.

Objective To study the correlation between ABCC3 gene and bladder cancer cell proliferation,drug resistance and aerobic glycolysis.Methods Lipofectamine 2000 reagent was used for small interfering RNA (siRNA) transfection.Human ABCC3 siRNA and negative control siRNA were transfected into UMUC-3 and 5637 cells separately,and bladder cancer cells were divided into siABCC3-1 group,siABCC3-2 group and control group.Western blot assay was used to evaluate the ABCC3 expression levels.Quantitative real-time polymerase chain reaction (PCR) was performed to determine the ABCC3 mRNA expression levels.The effect of ABCC3 on bladder cancer cell growth was determined by colony formation assay.We also analyzed the sensitivity of cance cells to cisplatin by MTT assay.The effect of ABCC3 on aerobic glycolysis were detected by measuring LDHA protein levels,lactate production and glucose consumption.The measurement data were expressed as ((x) ± s) tandard deviation.The difference between the groups was analyzed by single factor analysis of variance and LSD.Results Both protein and mRNA levels of ABCC3 were significantly decreased after si-ABCC3 transfection.Bladder cancer cells treated with si-ABCC3 exhibited significantly lower colony numbers than that of the control group.5637 cells treated with siABCC3-1 and siABCC3-2 were 4.02 μg/ml and 3.91 μg/ml,respectively.The IC50 values of cisplatin after UMUC-3 cells siABCC3-1 and siABCC3-2 were 2.54 μg/ml and 2.49 μg/ml,respectively.The expression of lactate dehydrogenase A protein in bladder cancer cells was down-regulated and the expression of ABCC3 was positively correlated with the expression of LDHA (P =0.0362).siABCC3-1 and siABCC3-2 were transfected into 5637 cells,respectively.The glucose consumption decreased by 43.2％ and 43.7％ respectively.The lactic acid production was reduced by 31.3％ and 29.7％,respectively.After transfection of UMUC-3 cells with siABCC3-1 and siABCC3-2,glucose consumption decreased by 33.4％ and 37.5％,respectively,and lactic acid production decreased by 24.7％ and 25.2％,respectively,compared with the control group,the difference was statistically significant (P ＜ 0.001).Conclusions ABCC3 is an important oncoprotein involved in cell proliferation,glycolysis and drug resistance.It could be a promising predictive biomarker and potential therapeutic target for bladder cancer.

Humans ; Severe Acute Respiratory Syndrome ; diagnosis ; therapy