Dornbusch K, Hagelberg A
Scand J Infect Dis. 1983;15(3):285-91. doi: 10.3109/inf.1983.15.issue-3.09.
The incidence of trimethoprim resistance (MIC greater than 4 micrograms/ml) among urinary pathogens from inpatients was earlier shown to be 1.6-3.6% in Stockholm and 31-49% in Turku in 1977-1978. In strains from this study trimethoprim resistance could be transferred from 13/51 donor strains. Resistance to streptomycin was co-transferred in all matings but 2, and to tetracycline, ampicillin, carbenicillin and chloramphenicol in some cases. Sulphonamide resistance was co-transferred in 2 cases. In all matings but 1 at least 1 plasmid was transferred. A plasmid with similar molecular weight was transferred from 5 Turku and 4 Stockholm donor strains. Restriction enzyme digestion of this plasmid DNA showed many common bands after electrophoresis. In DNA-DNA duplex studies, using 3H-labelled Col E 1::Tn 7 as the probe, the presence of Tn 7 DNA sequences was confirmed in the 5 donor strains from Turku and 1 from Stockholm. Electrophoresis of plasmid DNA with and without digestion with restriction enzymes together with DNA-hybridization were thus useful methods to investigate the presence of genetic determinants for trimethoprim resistance in 2 areas. Other determinants than transposon Tn 7 were also present.
在住院患者的尿路病原体中，甲氧苄啶耐药性（最低抑菌浓度大于4微克/毫升）的发生率，早期研究表明，1977 - 1978年在斯德哥尔摩为1.6 - 3.6%，在图尔库为31 - 49%。在本研究的菌株中，甲氧苄啶耐药性可从13/51的供体菌株中转移。除2次交配外，所有交配中链霉素耐药性均被共转移，在某些情况下，四环素、氨苄青霉素、羧苄青霉素和氯霉素耐药性也被共转移。2例中磺胺耐药性被共转移。除1次交配外，所有交配中至少转移了1个质粒。一个分子量相似的质粒从5个图尔库和4个斯德哥尔摩的供体菌株中转移。该质粒DNA经限制性酶切后电泳显示有许多共同条带。在DNA - DNA双链研究中，以3H标记的Col E 1::Tn 7作为探针，在来自图尔库的5个供体菌株和来自斯德哥尔摩的1个供体菌株中证实了Tn 7 DNA序列的存在。因此，质粒DNA经限制性酶切和未酶切的电泳以及DNA杂交是研究两个地区甲氧苄啶耐药性遗传决定因素存在情况的有用方法。除转座子Tn 7外还存在其他决定因素。
