用DNA杂交技术检测临床分离株的四种耐四环素基因

采用DNA杂交技术对来自我国几个省的306株革兰氏阴性杆菌携带的耐四环素基因(Tet)的分布进行了研究。所有菌株均用15种生化反应数码分析法判定，绿脓杆菌用双歧法鉴定。用四种Tet探针检测结果如下：TetB占31．4％，TetD占25．2％TetA占1 2.5％，TetC占10．5％。与四种探针均不杂交者占36．6％。含1种基因的菌株占51．3％，含2种的占7．5％，含3种的占2．9％，含4种的占1．6％。不同地区的菌株的Tet种类不完全相同。还发现在严格控制的条件下杂交，TetA和Tetc有交叉反应。

Use DNA techniques to detect tetracycline resistance genes in clinical strains

Our purpose in the present report was to use DNA techniques to analyse the distribution of Tetracycline resistance determinants among Gram negative bacteria and different location in our country. 306 clinical isolates, 102 out of which were isolated from nosocomial infections in Beijing Union Medical College Hospital from 1981-1986, were identified by fifteen kinds of biochemical reaction. According to sensibility test results, the percentage of resistant to antibiotics was that: Tetracycline 100%, Ampicillin 81.4%, Cefazolin 28.4%, Gentamycin 56.9%, Chloramphenicol 59.8%, TMP-SMZ 57.2%, Erythromycin 91.5%. The result of colony hybridization was that TetB (on R222) occurred at 31.4%, followed by TetD (on RA1) at 25.2%, TetA (on RP1) at 12.4% and TetC (on pSC101) at 10.5%, 36.6% of isolates failed to hybridize to any of the probes, while 51.3% harbored one determinant, 7.5% harbored two, 2.9% three and 1.6% four. Strains from some location contained TetB and TetD were slightly higher than TetC and TetA. At high stringency conditions of hybridization, we were able to show cross reaction of determinant C with TetA DNA, but no reaction with TetB and TetD DNA.