革兰阴性杆菌诱导酶、超广谱酶测定及影响因素探讨

The Determination of Inducible β Lactamase and Extended Spectrum β Lactamase and Their Affected Factors

对诱导型β-内酰胺酶及超广谱β-内酰胺酶 (ESBL )试验影响因素进行探讨 ,旨在提高两酶的阳性检出率。方法 :采用纸片相邻法 ,诱导酶测定以亚胺培南为诱导剂放平皿中央 ,周围以头孢他啶、头孢曲松等靶药物纸片与之相邻。 ESBL测定以复方阿莫西林放平皿中央 ,周围以头孢他啶、头孢曲松为底物与之相邻。结果 :诱导酶测定诱导剂与靶药物之间距离以 1 5mm为宜 ,靶药物以两种以上为佳 ,可以起到互补作用 ,并可提高其阳性率。ESBL测定复方阿莫西林和头孢曲松 (或头孢他啶 )之间的距离以 1 5mm为最佳 ,底物亦可选择两种以上三代头孢菌素 ,以提高 ESBL的阳性检出率。结论 :诱导酶和 ESBL测定可以弥补体外常规药敏试验之不足 ,对临床用药有重要的指导作用。

Objective To discuss the affected factors in the test of inducible β lactamase and extended spectrum β lactamase (ESBL) with the purpose of raising the rate of their positive strains.Methods The inducible β lactamase is determined by means of a modifed disk approximation test,i.e,imipenem as an inducer in the center and the target bata lactams are ceftriaxone(CRO)and ceftazidime(CAZ)et al placed bilaterally.The ESBL is determined by means of a modified disk approximation test i.e,Amoxicilin/clavulannic Acid(AMX/CA) in the center and the substances are CRO and CAZ placed bilaterally.Results 15mm is a desirable distance between the inducer and the target batalactams determined by inducible β lactamase.It is appropriate to have more than two target bata lactams which can be mutually complementary and can increase the positive rate.ESBL determines that a distance of 15 mm between CRO(or CAZ)and AMX/CA is the most satisfactory while more than two third generation of cephalosporins can also be chosen as a substance to raise the rate of positive strains.Conclusion The measurement of inducible β latamase and the extended spectrum β lactamases may be supplemental for the deficiency of the routine susceptibility tests.It plays an important guide role in the clinical administered drugs.