Biofilms Formation On Urinary Catheters From Critical Patients And The Eradicative Effect Of Irrigation

Objective1 To observe the biofilm formation on urinary catheters from critical patients.2 To analyse the risk factors of biofilm formation on urinary catheters from critical patients.3 To compare the eradicative effects of different irrigation methods in vitro.Methods1 50 critical patients who had lived in the surgical intensive care unit(SICU) with indwelling catheter were choosed.Changes on the surface of urinary catheters were observed when the catheters were withdrawed or replaced,catheter specimens were obtained for microorganisms identifcation and biofilms observation by scanning electron microscope(SEM).2 11 factors including age,the time of detaining urethral catheterization,24-hour urinary amounts,et al,were studied by single factor analysis and logistic regression analysis to analyse the risk factors of biofilm formation.3 Laboratory models of Candida albicans BF on catheters were prepared in the test tubes in vitro.All tubes were randomly divided into control group,infusion irrigation group and injection irrigation group.Control group were treated without irrigation,while irrigation groups with separate irrigations every 12h.Specimen were taken out for SEM observation at 12,24,48,72h.Results1 In 50 examples,gradeⅠchanges on the urinary catheters were 22 examples (44%),gradeⅡ9 examples(18%),gradeⅢ9 examples(38%);31 examples (62%) were detected microorganisms,while 19 examples(38%) were negative,the most common microbes were Candida albicans,Escherichia coli and Acinetobacter baumannii;BF formed mainly inside the catheter,BF formation inside the catheter were 29 cases(58%),non-BF 21 cases(42%);Microorganisms positive rate and BF formation rate increased with catheter longer duration;BF formation increased along with the aggravation of changes on the surface of urinary catheters and the increase of microorganisms positive rate.2 Single factor analysis revealed that there were significances in age,APACHEⅡscore,sex,urine sugar and the types of antibiotic usage among BF formation group and non-BF group,P＜0.05;Logistic regression analysis revealed that indwelling catheter time highly correlated with the biofilms formation,P＜0.05.3 In the early stage of Candida albicans BF formation,all experimental catheters were adhered by yeast cells,the amount of cells of irrigation groups were less than control group.With the maturation of BF,the experimental catheters were adhered by mycelium cells which graduallyres come to maturity,the thickness of BF of these 3 groups from high to low was control＞infusion irrigation＞injection.Conclusion1 Critically ill patients with indwelling catheters were of the high positive rate of microorganisms,and microorganism spectrum was of special properties;BF formed mainly inside the catheter,the occurrence rate of BF inside the catheter was high and the formation time was short;Changes on catheters and the result of microorganisms was positively correlated with the BF formation.2 Indwelling catheter time was the independent risk factors for the BF formatiom, while age,APACHEⅡscore,sex,urine sugar and the types of antibiotic usage were the potential risk factors for the BF formation;Nurses should perfect the catheter measures for critical ill patients,emphasis on the assessment of risk factors of BF formation,and implement special care in high-risk patients.3 In the early stage of BF formation,irrigation could play the role of eradicative BF effectively;While later,it couldn't,but it can delay the speed of BF formation and maturation;In the choice of washing methods,injection type washing method is superior to infusion.