尿路感染对尿中一氧化氮测量的干扰。
Interferences of urinary tract infection in the measurement of urinary nitrous oxide.
作者信息
Apostoli P, Gelmi M, Alessio L, Turano A
机构信息
Institute of Occupational Health, University of Brescia, Italy.
出版信息
Occup Environ Med. 1996 Sep;53(9):591-4. doi: 10.1136/oem.53.9.591.
OBJECTIVES
To investigate the effective role of micro-organisms in producing N2O.
METHODS
The N2O in either urine samples inoculated with 24 microbial strains or urine samples from patients with urinary tract infections were measured.
RESULTS
Gram negative bacilli generally produced high amounts of nitrous oxide (N2O), whereas Gram positive cocci and yeasts did not. The production of N2O depends on the incubation time and follows exponential kinetics, reaching a plateau at 48 hours. Furthermore, the results of urinocultures agreed well with N2O concentrations found in urine samples: samples negative for bacteria were found to contain very low concentrations of N2O whereas those positive--for example, for Enterobacteriaceae--gave highest N2O values.
CONCLUSION
The urinary tract infections caused by Gram negative bacilli are important confounding factors in biological monitoring practices of exposure to inhalation anaesthetics. The current methods adopted to avoid these factors (urine acidification, storage of samples at 4 degrees C) are not good enough because of the relative acid tolerance of some strains and the production of N2O directly into the bladder.
目的
研究微生物在产生一氧化二氮（N2O）中的作用。
方法
对接种了24种微生物菌株的尿液样本以及尿路感染患者的尿液样本中的N2O进行测量。
结果
革兰氏阴性杆菌通常会产生大量一氧化二氮（N2O），而革兰氏阳性球菌和酵母则不会。N2O的产生取决于培养时间，并遵循指数动力学，在48小时时达到平稳状态。此外，尿液培养结果与尿液样本中发现的N2O浓度非常吻合：细菌检测呈阴性的样本中N2O浓度非常低，而阳性样本——例如肠杆菌科阳性样本——的N2O值最高。
结论
革兰氏阴性杆菌引起的尿路感染是吸入性麻醉剂暴露生物监测实践中的重要混杂因素。由于某些菌株具有相对耐酸性且N2O直接在膀胱中产生，目前用于避免这些因素的方法（尿液酸化、样本在4℃下保存）并不够完善。
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