无菌水清洗法减低中段尿培养假阴性的效果观察

目的比较高锰酸钾溶液清洗消毒法与无菌水清洗法对中段尿培养结果的影响。方法采集2002年1月-2006年12月符合留取中段尿培养指征的住院患者的尿标本．将采用1：5000高锰酸钾溶液清洗、消毒法留取的尿样本列为消毒组（n=1572）；将采用无菌反渗水（血透用）清洗法采集的尿标本列为清洗组（n=544）；观察2组标本微生物培养阳性率及污染率的变化；培养出2种以上细菌定义为污染。结果5年共入选830例尿路感染患者，收集中段尿标本2116例，共检出病原体531株；消毒组和清洗组尿标本的微生物阳性检出率分别为20．04％和39．71％．2组比较差异显著；消毒组同一患者2次培养检出相同致病微生物的百分比为0．012％，清洗组则为0．105％，二者比较差异显著。但是同一患者2次培养检出不同和仅单次致病微生物的发生率比较差异不显著。消毒组的污染率（0．028％）显著高于清洗组（0．007％）。结论无菌水清洗留取中段尿在没有增加污染率的情况下，可显著提高尿培养致病微生物的阳性率；高锰酸钾溶液消毒法可能是导致培养高假阴性的原因。

Observation in effect of perineal cleansing with sterile water on reduction of the false negative rate of mid-stream urine culture

Objective To compare the effect of perineal cleansing with the potassium permanganate or sterile water on midstream urine culture. Methods Midstream specimens of urine were obtained from inpatients in our hospital between January 2002 and December 2006. All these patients may be diagnosed as urinary, tract infection. The urine specimens were divided into the potassium permanganate group （n= 1572, the sterilization group） and the sterile water group （n=544）. The change of positive and contami- nation rate of mid-stream urine culture from the specimens was observed. More than two kinds of germs in one urine specimen were defined as contamination. Results 830 patients with urinary tract infection had been enrolled. 2116 specimens were collected and 531 strains of causative organism were detected. The positive rate of the sterilization group and the sterile water group was 20.04% and 39.71%, respectively,and such difference was significant. The rate of identical causative organism from the same patient whose speeimen was cultivated twice in the sterilization group was 0.012% and the rate was 0.105% in the sterile water group. The difference was significant. The rate of different or one kind of causative organism from the same patient whose specimen was cultivated twice in these two groups hadn＇t significant deviation. The contamination rate of the sterilization group （0.028%） was significantly higher than that of the sterile water group （0.007%）. Conclusions Perineal cleansing with sterile water can reduce the false negative rate of midstream urine culture without increasing the contamination rate. Potassium permanganate sterilization is responsible for the high false- negative in mid- stream urine culture.