Mawer S L, Greenwood D
J Clin Pathol. 1978 Jan;31(1):12-5. doi: 10.1136/jcp.31.1.12.
The turbidimetric responses of a strain of Escherichia coli K12 to gentamicin and tobramycin were investigated. Both agents showed antibacterial activity below the conventionally measured minimum inhibitory concentration, but exposure to such subinhibitory concentrations of either agent generated a bacterial population which was able to grow in previously inhibitory concentrations at a rate equivalent to that of the parent culture. The increase in resistance was non-specific in that both aminoglycosides were equally affected, and was unstable on multiple passage in drug-free broth. The response to tobramycin was unaffected by the presence of an R factor conferring gentamicin resistance, but exposure of the R factor bearing strain to gentamicin caused a concomitant increase in the resistance to tobramycin, apparently by a non-specific adaptive mechanism similar to that observed with the parent strain. It is suggested that prior treatment of a gentamicin-resistant organism with gentamicin (as may occur during blind therapy) may adversely affect the subsequent response to other aminoglycosides.
研究了一株大肠杆菌K12对庆大霉素和妥布霉素的比浊反应。两种药物在低于常规测定的最低抑菌浓度时均显示出抗菌活性，但暴露于这种亚抑菌浓度的任何一种药物都会产生一个细菌群体，该群体能够在先前的抑制浓度下以与亲代培养物相当的速率生长。耐药性的增加是非特异性的，因为两种氨基糖苷类药物受到的影响相同，并且在无药物肉汤中多次传代时不稳定。对妥布霉素的反应不受赋予庆大霉素耐药性的R因子的影响，但携带R因子的菌株暴露于庆大霉素会导致对妥布霉素的耐药性同时增加，显然是通过一种类似于在亲代菌株中观察到的非特异性适应性机制。有人提出，用庆大霉素对庆大霉素耐药的生物体进行预先治疗（如在盲目治疗期间可能发生的情况）可能会对随后对其他氨基糖苷类药物的反应产生不利影响。
