Research On The Sensitivity Test Of Pseudomonas Aeruginosa In Vitro By Flow Cytometry

Objective Traditional antibiotic susceptibility testing methods include broth dilution and agar dilution. In the clinical tests of disc diffusion and VITEK instrument, as well as micro-dilution or E-test, bacteria should be cultivated with drugs overnight, which are time-consuming. Judgments are usually based on the presence or absence of visually discernible bacterial growth, which only indicates an average value of bacterial group growth. Flow cytometry can be used to analyze the individual cell rapidly. It has been applied in many fields in biomedical science. Although flow cytometry was first employed to study the activities of microorganism abroad as early as in the 80s of the 20th century, up to now, the related reports are few in China. At present, the pseudomonas aeruginosa(PA) is one of the three major bacteria which were frequently isolated from nosocomial infection patients. In our study we try to explore a rapid method with which can provide the results of sensitivity testing of those germs accurately and timely. If the method was established successfully, it is important to prevent and cure the infection disease, we hope that it not only reduce the emergence and spreading of the multi-resistant species, but also decrease the burden of patients and hospitals.In the study the fluorescent substance Propidium iodide(PI) was chosen to penetrate the broken bacterial cell membrane and bind with nucleic acid. The existence rate of live bacteria in the culture after drug treatment was determined according to the fluorescence strength by flow cytometry. The susceptibility to Imipenem of 1 standard strain and 22 isolates of PA were tested by FCM, the results were compared with those obtained by micro-dilution method. It demonstrated that flow cytoflurometric antibiotic susceptibility test(FCST) was more rapid, sensitive, accurate and objective than conventional methods. Method One standard strain of PA ATCC27853 was purchased from Beijing. 22 strains of PA collected from the laboratory of Children's Hospital of Suzhou University, isolated from the nosocomial patients in Surgery and ICU ward during the period of 2003-1-1 to...