Hayward N J, Jeavons T H, Nicholson A J, Thornton A G
J Clin Microbiol. 1977 Sep;6(3):195-201. doi: 10.1128/jcm.6.3.195-201.1977.
Proteus mirabilis was distinguishable from Escherichia coli and from several other species that may be associated with urinary tract infections when grown in a nutrient medium supplemented with 0.1 M L-methionine by the formation of large amounts of dimethyl disulfide and methyl mercaptan, which were detected by head-space gas-liquid chromatography (HS-GLC). E. coli could be detected by the same HS-GLC technique by ethanol production from methionine peptone water enriched with 1% either lactose or arabinose but not by any product from 10 amino acids tested. Ethanol from lactose was detected early in the exponential phase of growth. Significant numbers, 10(5) or more per ml, of E. coli in urine could be detected in about 5 h by ethanol production from an unshaken culture of urine in lactose methionine peptone water buffered at pH 7.2 (urine test medium); only a trace of dimethyl disulfide was produced. Significant numbers of P. mirabilis in urine could be detected in 4 h by dimethyl disulfide production and in 5 h by methyl mercaptan production from a shaken culture of urine in urine test medium; no ethanol was produced. Incubation of urine specimens in the test medium followed by examination by HS-GLC is proposed as a rapid method of detecting whether or not the urine contains significant numbers of E. coli or a species of Proteus.
奇异变形杆菌与大肠杆菌以及其他几种可能与尿路感染相关的菌种有所不同。当在添加了0.1M L-甲硫氨酸的营养培养基中培养时，奇异变形杆菌会形成大量二甲基二硫和甲硫醇，可通过顶空气相色谱法（HS-GLC）检测到。大肠杆菌可通过相同的HS-GLC技术，利用富含1%乳糖或阿拉伯糖的甲硫氨酸蛋白胨水产生乙醇来检测，但用所测试的10种氨基酸均无法检测到相关产物。乳糖产生的乙醇在生长指数期早期即可检测到。通过在pH 7.2缓冲的乳糖甲硫氨酸蛋白胨水（尿液测试培养基）中对未振荡的尿液培养物产生乙醇，大约5小时可检测到每毫升尿液中数量达到10⁵或更多的大肠杆菌；仅产生微量二甲基二硫。通过尿液测试培养基中振荡的尿液培养物产生二甲基二硫，4小时可检测到尿液中大量的奇异变形杆菌，通过产生甲硫醇则在5小时可检测到；未产生乙醇。建议将尿液标本在测试培养基中培养后通过HS-GLC进行检测，作为一种快速检测尿液中是否含有大量大肠杆菌或变形杆菌属菌种的方法。
