Objective To construct Pseudomonas aeruginosa(PA)strain with deletion of the pyocyanin synthesis gene PAOⅡ and investigate its drug resistance.Methods By analyzing the ge-nome of the PAOⅡ genotype strain of PA,the distribution of genes/gene clusters related to pyocyanin synthesis in the genome was explored.A strain with deletion of the pyocyanin synthesis gene phzM was constructed using homologous recombination-based seamless gene knockout technology.The growth and drug tolerance of the wild-type and mutant strains were compared.Results Kyoto Encyclopedia of Genes and Genomes(KEGG)clustering analysis was performed on the website https://www.kegg.jp/.The results revealed a gene cluster composed of 9 genes(including PhzA,PhzB,PhzC,PhzD,PhzE,PhzF,PhzG,phzM and PhzS),which was completely consistent with the KEGG PATHWAY:Phenazine biosynthesis-M00835 Pyocyanine biosynthesis pathway.The key gene phzM for pyocyanin synthesis was knocked out via homologous recombination.After the exchange,monoclonal strains growing on M9-citrate medium were verified using primers phzM-AF and phzM-BR.The shuttle plasmid pK18mobSacB-phzM-AB was successfully transfected into the PAOⅡ genotype strain.After gene ex-change,monoclonal strains capable of growing on antibiotic-free plates were selected,and polymerase chain reaction(PCR)was performed to obtain strains with successful scarless knockout of the phzM gene.At 3 and 6 days of culture,the biofilm formation thickness of the PAOⅡ genotype strain was greater than that of the PAOⅡ-△phzM strain,with a statistically significant difference(P＜0.05).Conclusion The biofilm synthesis capacity of the pyocyanin synthesis-deficient strain is reduced,and its resistance to cephalosporins(ceftazidime)is also decreased.

Objective To evaluate the efficacy,safety and side effects of 0.5% povidone-iodine in intravesical treatment of interstitial cystitis (IC). Methods Thirty-three cases of IC were divided randomly into group A (18 cases) and group B (15 cases). Group A was treated by intravesical instillation with 50 ml of 0.5% povidone-iodine which was kept in the bladder for 2 hours,once a day for 2 weeks. Group B was treated in the same way,but with 1:5000 furacilin instead. The symptoms,results of cystoscope inspect and adverse effects were investigated. Results All cases were followed up from 8 to 22 months (in average of 18 months). There was significant difference in the scores of clinical symptoms after treatment between two groups (P

Objective To assess the feasibility of intracavitary drainage using three equally-sized double pigtail stents in the treatment of ureteral stricture. Methods Placement of three identical double pigtail stents in ureters for indwelling for 10～12 weeks was carried out in 27 cases of ureteral stricture from March 2000 to June 2003. Results The patients were followed for 2～24 months, with a mean of 18 months. No lumbar distending pain or fever occurred after the removal of the drainage in 26 cases, with the IVP examination indicating patency drainage and no ureteral stricture. Re-examination of IVP 6 months after the surgery found no improvement of hydronephrosis in 1 case. The overall success rate was 96% (26/27). Conclusions Intracavitary drainage using three equally-sized double pigtail stents in the treatment of ureteral stricture is feasible.