| The method for measuring the outer membrane (OM) peameability of Pseudomonas aeruginosa (PA) clinical isolates was reported. An OprD2 gene was cloned and expressed in E. coli from PA. The relationship between OM proteins and antimicrobial resistance was studied and on this basis, a screening method for antimicrobial agents from microorganism was described.A feasible method of measuring antibiotics penetration through OM of PA was established in this study. OM permeability to cefazolin and Tienam of clinical isolates of PA which were resistant to β-lactam antibiotics (at least to one sort of β-lactam antibiotics) was tested.In order to study the relationship between OM permeability and drug resistance of PA, Tienam-resistant strains 715/R1 and 715/R2 were obtained by mutagenesis with ultraviolet ray and NTG from clinical isolate 715 strain of PA, which was susceptible to Tienam (MIC was 2 μg/ml). MICs of 715/R1 and 715/R2 were 64 μg/ml. Analyzing the OM protein by SDS-PAGE revealed that a 4549kDa protein band existed in the susceptible type strain 715 and was absent in resistant strain 715/R1 and 715/R2. OM permeability to Tienam was decreased to 36.54% and 30.13%, respectively, from 100% of 715 strain. These data showed that resistance of PA to Tienam was related to a decrease in OM permeability owned to lacking of certain OM protein.Two primers were designed and synthesized according to gene sequence of related OM protein (OprD2), 1.3kb DNA fragment was amplified by PCR technique using total DNA of Pseudomonas aeruginosa PAO1 as a template. DNA sequence analysis showed no difference with OprD2 gene. The amplified gene was cloned into...
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