Pathogenic distribution and drug resistance of bacterial biofilm on ureteral stent / 中国组织工程研究

ABSTRACT

BACKGROUND: Ureteral stents have been extensively applied In the stenosis In the conjunction of the renal pelvis and ureter, the reconstruction of in situ urine flow, ureter or nephroscope lithotripsy, renal transplant, and tumors. However, the long-term retention of ureteral stents can induce catheter-associated urinary tract Infection complications. OBJECTIVE: To Investigate the morphological characteristics of bacterial blofilm on ureteral stent, and to analyze the features of pathogenic distribution and antimicrobial drug resistance to bacterial biofilm. METHODS: Specimens of ureteral stent were collected from 127 patients at Yongchuan Hospital, Chongqing Medical University between January and December 2016. The morphological characteristics of bacterial blofilm on the stent were observed under scanning electron microscope. Each specimen was divided Into three parts (renal pelvis, ureter and bladder) for screening biofilm-forming bacteria strains separately by Congo red medium. The urine was bacterially cultured. Drug susceptibility test was done with the collected biofilm-forming bacteria strains. The study was approved by the Ethics Committee of Yongchuan Hospital, Chongqing Medical University (approval No. 201422). RESULTS AND CONCLUSION: (1) Bacterial blofilm was observed on the surface of ureteral stents at 7,15 and 30 days of retention, with various numbers of inflammatory attachments or crystals. Bacteria on the bacterial biofilm were embraced by large amounts of fiber membranes. Patchy bacterial colonies were observed on the surface of the ureteral stent at 7 and 15 days of retention, which mainly focused on bacillus. Heap-shaped bacterial colonies were found on the surface of ureteral stents that were retained for 30 days, which mainly were bacillus and coccus. (2) A total of 106 bacterial blofilms were detected in the ureteral stent samples obtained from 127 patients. The positive rate was 83.5%, in which the bladder section had the highest positive rate, followed by the renal pelvis section and ureter section. There were 25 copies of positive urine culture, and the positive rate was 19.7%. The strains obtained from the bacterial biofilm on each section of the ureteral stents were significantly higher than that from the urine bacteria culture (P < 0.05). (3) A total of 227 strains were detected from 106 positive samples. Among these samples, the number of Gram-negative strains was significantly higher than that of Gram-positive strains (P < 0.05). Among culture bacteria of the bacterial biofilm on the ureteral stent and urine culture bacteria, colibacillus, pseudomonas aeruginosa, enterococcus faecalis and enterococcus faecium were the most common. (4) The biofilm-forming bacteria on the ureteral stent had a high drug resistance. (5) In summary, bacterial blofilm may be the important reason for catheter-associated urinary tract infection.