Study On Drug Resistance And Producing Extended-spectrum β-Lactamases Of Pseudomonas Aeruginosa

Objective To investigate the drug resistance of Pseudomonas aeruginosa in nosocmial infection and the gene type of extended spectrumβ-lactamases(ESBLs)producing strains.Methods Various clinical specimens collected from patients of nosocomial infection were cultured to isolate bacteria according to routine method,and bacteria identification was made by Phoenix-100 system.Drug sensitivity test was performed by taking Kirby-Bauer slip diffusion method based on the standard of NCCIS;the strains suspected producing ESBLs-producing strains of Pseudomonas aeruginosa were taken by Kirby-Bauer slip diffusion ESBLs-detecting method initially and finally genes of ESBLs was definited by PCR.Results 64 strains of Pseudomonas aeruginosa were detected by Phoenix-100 system in clinical specimens.The results of drug sensitivity tests showed drug resistance rate of Pseudomonas aeruginosa was all high(over 90%)to penicillins,the first generation cephalosporins,the second generation cephalosporins,cefoxitin and Sulfanilamide,that to the third generation cephalosporins was in 20%-50%,to imipenem was 15.6%,to ticarcillin-clavulanic acid was 20.3%,to amikacin was 32.8%,and to ciprofloxacin was 29.7%.27 ESBLs-producing strains of Pseudomonas aeruginosa were confirmed by Kirby-Bauer slip diffusion ESBLs-detecting method.Being compared resistance between ESBLs-producing strains and non-ESBLs-producing strains,resistance of ESBLs-producing strains to piperacillin,cefoperazone,ceftriaxone and aztreonam were much higher than that of non-ESBLs-producing strains(P＜0.05).TEM type gene was confirmed in plasmidic DNA and chromosomal DNA of 20 strains of Pseudomonas aeruginosa by PCR.OXA-10 type gene was positive in plasmidic DNA of 4 strains and that was positive in chromosomal DNA of 2 strains,meanwhile TEM and OXA-10 type gene were confirmed in same plasmidic DNA of 1 strain.Conclusions Drug resistance rate of Pseudomonas aeruginosa to antibiotics in nosocomial infection was different from other regions in China;ESBLs-producing rate of Pseudomonas aeruginosa was high,TEM and OXA-10 type gene were confirmed in ESBLs-producing strains ofPseudomonas aeruginosa,TEM type gene was much.Drug resistance of Pseudomonas aeruginosa was complicate,mechanism of drug resistance to the third generation cephalosporins was related to ESBLs principally.