A Study On Typing Of Acinetobacter Baumannii By Random Amplification Polymorphic DNA

Objectives: To establish the random amplification polymorphic DNA (RAPD) typing method for Acinetobacter baumannii and apply it in the clinical strain identification and epidemiology investigation, in addition,to compare RAPD analysis and antibiograms. Methods: Antibiotyping and molecular typing with RAPD technique were applied respectively to type 27 strains of Acinetobacter baumannii and microbiological sampling from the ward environment and surface of doctors'and nurses' hands and clean liquid of sputum aspirator were cultured and identified ,and then determinate the source of cross-infection in hospital.Results: 27 strains were divided into 4 different antibiotic resistance patterns, 15(55.6%) strains were pattern I ,8(29.6%)strains were pattern II ,2(7.4%) strain was pattern HI, the other 2(7.4%) strains were pattern IV,the dominant strains were pattern I . 27 strains were divided into 9 RAPD profiles, 14(51.9%) strains had the same profiles(genotype "A"), genotype "B,C,D,E,H" had 2(7.4%) strains respectively, the other 3 strains had another three different profiles (genotype "F,G,I"), the main strains were genotype "A". 1 strain (genotype "A",antibiogram pattern I )was obtained from clean liquid of sputum aspirator ,1 strain was obtained from one nurse's hands and the door handles of ICU respectively, genotype both were "A"and antibiogram patterns were I ,these results suggested that there was patient-to-patient spread of strains in ICU. The samples culture of other ward and hands of doctors and nurses were passive and then sterilized the ICU ward. After 2 mouths , there was not new infection of Acinetobacter baumannii. Conclusion: Genotype "A" and antibiogram pattern I of Acinetobacter baumannii was epidemic relative strains leading this cross-infection outbreak in ICU, and the other strains were not epidemic relative strains. Within antibiogram patterns, isolates could be further classified based on their RAPD types, strains of different genetic types had similar antibiograms. While antibiograms alone are not sufficiently discriminatory .Genotype with RAPD was more sensitive and specific than antibiogrames typing,further more with the characters of simple, rapid and reliable, it would be valuable in epidemiological investigation of hospital infection.Medical College of Qingdao University Postgraduate Fei jianwen(internal medicine) Directed by Qin xiaomeiCheng zhaozhong...