Butcher P D, Cevallos A M, Carnaby S, Alstead E M, Swarbrick E T, Farthing M J
Department of Gastroenterology, St Bartholomew's Hospital, West Smithfield, London.
Gut. 1994 Jan;35(1):51-4. doi: 10.1136/gut.35.1.51.
Two Giardia isolates were axenised in vitro after recovery by duodenal aspiration from a man with hypo-gamma globulinaemia and chronic giardiasis, before and after three unsuccessful courses of metronidazole. In vitro drug sensitivity assays showed that the pretreatment isolate was sensitive to metronidazole with minimum inhibitory concentration (MIC) and dose that inhibited growth by 50% (ED50) values of 0.1 and 0.03 mumol/l, respectively. The post-treatment isolate was 20-fold more resistant (MIC and ED50 4.3 and 0.58 mumol/l, respectively). Differences between these isolates were also found in the surface protein profiles after radioiodination, metabolic labelling patterns with 35S-methionine, malic enzyme isoenzyme patterns, and by DNA fingerprinting with a M-13 bacteriophage probe. The phenotypic and genotypic differences between the pretreatment and post-treatment isolates suggest that we have isolated two different strains from the same patient and that treatment with metronidazole resulted in selection of the more resistant strain.
从一名患有低丙种球蛋白血症和慢性贾第虫病的男子十二指肠抽吸物中分离出的两株贾第虫，在接受三个疗程甲硝唑治疗失败前后，进行了体外无共生培养。体外药敏试验表明，治疗前分离株对甲硝唑敏感，最小抑菌浓度（MIC）和抑制生长50%的剂量（ED50）分别为0.1和0.03μmol/L。治疗后分离株的耐药性高20倍（MIC和ED50分别为4.3和0.58μmol/L）。在放射性碘化后的表面蛋白图谱、用35S-甲硫氨酸进行的代谢标记模式、苹果酸酶同工酶模式以及用M-13噬菌体探针进行的DNA指纹分析中，也发现了这些分离株之间的差异。治疗前和治疗后分离株之间的表型和基因型差异表明，我们从同一患者中分离出了两种不同的菌株，甲硝唑治疗导致了更耐药菌株的选择。
