Lewis E L, Lacey R W
J Clin Pathol. 1973 Mar;26(3):175-80. doi: 10.1136/jcp.26.3.175.
The incidence of trimethoprim resistance in coliforms and multiresistant strains of Staphylococcus aureus isolated in Bristol from 1970 to 1972 is low-2.3 and 1.0% respectively. The resistance is probably intrinsic; there is no evidence that it is R-factor or plasmid mediated. A single mechanism that confers resistance to both trimethoprim and sulphamethoxazole has not been detected. Normal growing one-step mutants of S. aureus and Escherichia coli resistant to trimethoprim could not be isolated in vitro. For these reasons cotrimoxazole should retain its usefulness against these bacteria for some years. However, contrimoxazole was found not to be bactericidal against many coliforms. The usefulness of cotrimoxazole against Streptococcus faecalis seems limited because mutants resistant to trimethoprim occurred at high frequency in one step.
1970年至1972年在布里斯托尔分离出的大肠菌和耐多种抗生素的金黄色葡萄球菌菌株中，甲氧苄啶耐药性的发生率较低，分别为2.3%和1.0%。这种耐药性可能是内在的；没有证据表明它是由R因子或质粒介导的。尚未检测到一种能同时赋予对甲氧苄啶和磺胺甲恶唑耐药性的单一机制。在体外无法分离出对甲氧苄啶耐药的金黄色葡萄球菌和大肠杆菌的正常生长的一步突变体。由于这些原因，复方新诺明在未来几年内对这些细菌仍应有效。然而，发现复方新诺明对许多大肠菌没有杀菌作用。复方新诺明对粪链球菌的有效性似乎有限，因为对甲氧苄啶耐药的突变体在一步中出现的频率很高。
