蛇毒抗菌肽OH-CATH对大肠杆菌引起家兔泌尿系感染的保护作用

为探讨蛇毒抗菌肽OH-CATH对大肠杆菌标准株和临床耐药株引起家兔泌尿系感染的保护作用,该文利用大肠杆菌标准株(E.coli ATCC 25922)和耐头孢菌素大肠杆菌临床耐药株建立雄性家兔泌尿系感染模型.通过膀胱直接给药的方式,分别给予动物感染模型生理盐水、蛇毒抗菌肽OH-CATH及头孢哌酮舒巴坦,并于给药后第1、5、l0及14天留取家兔中段尿用于尿液培养.将动物膀胱标本行H-E染色石蜡切片及透射电镜观察.结果显示:使用蛇毒抗菌肽OH-CATH的大肠杆菌标准株和临床耐药株不同组别中段尿培养阳性率明显降低;给予头孢哌酮舒巴坦可降低大肠杆菌标准株(E.coli ATCC 25922)引起感染的阳性率,但对耐头孢菌素大肠杆菌引起的感染的阳性率则无明显作用(P＜0.05);使用蛇毒抗菌肽OH-CATH组炎症细胞浸润、坏死及钙化组织较其他组为少.该结果提示蛇毒抗菌肽OH-CATH对大肠杆菌标准株(E.coli ATCC 25922)及耐头孢菌素大肠埃希菌临床耐药株有稳定活性,对其引起的家兔泌尿系感染有较好的保护作用,并为临床日益严重的耐药病原菌感染的治疗提供了新的思路和方向.

Protective effects of snake venom antimicrobial peptide OH-CATH on E. coli induced rabbit urinary tract infection models

To investigate the potential protective effects of the snake venom antimicrobial peptide OH-CATH, we used a series of rabbit urinary tract infection models successfully induced by cephalosporin-resistant E.coli and E. coli ATCC 25922. The experimental models were administered saline, snake venom antimicrobial peptide OH-CATH, Cefoperazone and Sulbactam through the urethra. Urine was collected on days 1, 5, 10 and 14 after model establishment and urine culture was done to check the infection in each experimental animals. On day 14, all the animals were sacrificed and the bladder tissue specimens were taken for observation by H-E staining light microscope and transmission electron microscope. We found that the snake venom antimicrobial peptide OH-CATH reduced bacterial count in urine culture in both cephalosporin-resistant E. coli and the E. coli ATCC 25922 infected animals, while Cefoperazone and Sulbactam were only able to reduce the positive rate induced by the E. coli ATCC 25922 but had no obvious effects on animal model induced by cephalosporin-resistant E. coli strains (P<0.05). We also found less necrosis, degeneration and inflammatory cell infiltration in bladder tissue in OH-CATH groups as compared with the other experimental groups. The snake venom antimicrobial peptide OH-CATH had stable antibacterial activity against cephalosporin-resistant E. coli and E. coli ATCC 25922 and exhibited protective effects on both the cephalosporin-resistant E. coli and E. coli ATCC 25922 rabbit urinary tract infection models, suggesting that the molecule may have potential clinical applications in treating urinary tract infections.