Alalysis Of Antimicobial Agents Resistance Of Pseudomonas Aeruginosa And β-lactamase Resistance Genes Of Its Multi-drug Resistant Stains

Objective:To investigate the resistance to 14 antimicrobial agents about 90 strains of Pseudomonas aeruginosa from the lower respiratory tract and guide rational use of antimicrobial agents to clinical therapy。To detect beta-lactamase and study resistance genes of multi-drug resistant Pseudomonas aeruginosa Isolates。Materials and Methods:Totally 90 clinical isolates of PA were collected from the lower respiratory tract of the first affiliated hospital of Anhui medical university in 2009。Microscan WalkAway - 40 automatic microbial analyzer and related products, Negative Combo Panel Type 31 was used to detect the identification tests。In 39 multi-resistant Pseudomonas aeruginosa, Extended-spectrumβ-lactamase (ESBLs),AmpC enzymes and Metallo-β-lactamase (MBLs) screened by three-dimension test and disc synergy test。Polymerase chain reaction (PCR) technical is utilized to amplify beta-lactamase and OprD gene,DNA sequencing was adopted to analyze the resistance-related genes。Results:In vitro susceptibility tests of 14 antimicrobial agents, Aminoglycoside antibiotics showed a high sensitivity:amikacin (70%), Tobramycin (68%), gentamicin (59%), respectively. Followed by ciprofloxacin (58%), imipenem (56%), levofloxacin (54%), cefepime (50%); The highest resistance is Piperacillin/ tazobactam,Piperacillin,Picarcillin/clavulanic( 100%)。Three-dimensional test results showed that 7 producing ESBLs (25.9%), 5 producing AmpC enzymes (18.5%), 4 simultaneous production of ESBLs + AmpC enzymes (14.8%), EDTA synergy test detected 4 producing MBLs(14.8%)。PCR results showed that 7 strains of ESBLs-producing were positive for OXA-10 gene same as three-dimension test founded, 2 strains of MBL-producing were positive for VIM-2 gene, OprD gene was negative in 34 strain , The rest of resistance gene was not detected。Conclusion:The 90 strains of P. aeruginosa are varying degrees of resistant to 14 antimicrobial agents, Aminoglycosides and quinolones are more susceptible antibiotic to PA; Penicillin and inhibitors ofβ-lactam antibiotics in the treatment process could produce induced enzyme to bacterial resistance; The third generation cephalosporins, aztreanam are not appropriate in treating clinical infections caused by P.aeruginosa。At present Aminoglycosides and quinolones are the first choice to treat lower respiratory tract infections caused by P.aeruginosa, carbapenem and the forth-generation cephalosporins following ; However, due to aminoglycosides and quinolones found to have renal toxicity, ototoxicity and central nervous system reactions and other side effects during treatment, attention should be paid。Anti-infective therapy should be based on the results of antimicrobial susceptibility test to regulate drug treatment and prevent the resistance of bacteria , avoid the generation of resistant strains。This study indicated that these P. aeruginosa carried genes of OXA-10,VIM-2 and loss of OprD gene, which were the essential resistance mechanism of MDRPA to beta-lactamase antibiotics in our hospital。Beta-lactamase detected by three-dimension test and disc synergy test which is an accurate, easy, economic, easy operating method。...