Waley S G
Sir William Dunn School of Pathology, University of Oxford, UK.
Microbiol Sci. 1987 May;4(5):143-6.
The effectiveness of beta-lactam antibiotics against Gram-negative bacteria that contain beta-lactamases is considered in terms of three factors. These are a rate constant for reaction of the beta-lactam antibiotic with a transpeptidase, the kinetic parameters for hydrolysis of the antibiotic by the beta-lactamase, and the permeability of the outer membrane. The concept of a dimensionless permeability number (Pn) is developed. When the permeability number is much less than one then permeability is important, and the MIC may be raised by a factor of up to 1/Pn. When the antibiotic is sufficiently reactive its effectiveness is given by the 'reactivity-permeability' product.
β-内酰胺抗生素对含有β-内酰胺酶的革兰氏阴性菌的有效性可从三个因素来考虑。这些因素是β-内酰胺抗生素与转肽酶反应的速率常数、β-内酰胺酶水解抗生素的动力学参数以及外膜的通透性。提出了无量纲通透性数（Pn）的概念。当通透性数远小于1时，通透性很重要，最低抑菌浓度（MIC）可能会提高到1/Pn倍。当抗生素具有足够的反应活性时，其有效性由“反应活性-通透性”乘积决定。
