Prevalence of efflux mediated ciprofloxacin and levofloxacin resistance in pseudomonas aeruginosa urinary isolates

Pseudoinonas aeruginosa [P. aeruginosa] represents a phenomenon of antibiotic resistance, and demonstrates practically all known mechanisms of bacterial resistance. Active efflux is an important mechanism of resistance in P. aeruginosa. It contributes to the development of multiple resistances to all strategic antipseudonional antibiotics. More than five hundred urine samples were collected from patients in Assiut University Hospital. Fifty P. aeruginosa isolates were identified by conventional methods. The antibiotic susceptihity testing of isolates showed that 68% of isolates were resistant to ciprofloxacin and 62% were resistant to levofloxacin. A comparison between the effect of three efflux pump inhibitors [Reserpine, Pantoprazole and Carbonyl cyanide m-chlorophenylhydrazone [CCCP]] on the activity of ciprofloxacin and levofloxacin was done by measuring ability of these agents to potentiate effect of ciprofloxacin and levofloxacin against resistant P. aeruginosa isolates. Outer membrane profile of P. aeruginosa isolates was also done using sodium dodecyl sulfate polyacrylamide gel electrophoresis [SDS-PAGE]. Reserpine was able to potentiate effect of ciprofloxacin in 50% of isolates, and in 5.5% for levofloxacin. Pantoprazole results were 33.3% for ciprofloxacin, 16 7% for levofloxacin. Finally CCCP potentiate. Regarding the SDS-PAGE of P. aeruginosa isolates, all isolates produced proteins with apparent molecular masses in the range of 50-54kDa.Reserpine-ciprofloxacin proved to be the best combination against multidrug resistant P. aeruginosa. Over production of 50-54 KDa outer membrane proteins is responsible for emergence of P. aeruginosa strains highly resistant to fluoroquinolones in clinical settings

[Relation between quinolones and beta-lactams resistance with feature of producing capsules in pseudomonas aeruginosa isolated from urine]

Pseudomonas aeruginosa as an opportunistic pathogen is the most important infectious agent in hospital and has resistance to the common antibiotics. In this study, susceptibility of pseudomonas aeruginosa to quinolones and beta-lactams, and also relation of bacterial capsule and antibiotic resistance were assessed. In this experimental study, 100 strains of pseudomonas aeruginosa from Imam Khomeini hospital were collected and its susceptibility to some of quinolones and beta lactams was determined on the basis of the minimum inhibitory concentration on agar. In order to detection mucoid and non-mucoid strain, capsule was detected by India- ink staining and alginate precipitation methods, and then relation of bacterial capsule and antibiotic resistance was evaluated. MIC method demonstrated 90% susceptibility to ofloxacin, 89% to ciprofloxacin, 59% to nalidixic acid, 43% to ceftizoxime and 39% to ceftriaxone. The susceptibility of these strains was also examined on the basis of disk diffusion agar on moler Hinton medium, and susceptibility to used antibiotics was as following: co-amoxiclave 0%, ceftizoxime 23%, ceftriaxone 29%, carbenicillin 48%, nalidixic acid 50%, Ticarecillin 53%, Ciprofloxacin 36%, ofloxacin 70% and norfloxacin 89%. All strains had alginate capsule and only diameter of capsules was different between strains. This study showed that the method of disc diffusion has less accuracy compared to MIC in determining susceptibility to antibiotics