Proton gradient – dependent efflux pumps play important role in multidrug resistance (MDR) in PSEUDOMONAS AERUGINOSA. 23 MDR strains were selected from 104 clinical isolates of P. AERUGINOSA and screened for resistance to ceftazidim, ceftriaxone, ciprofloxacin, ofloxacin, amikacin, gentamicin and ethidium bromide by determining MICs. The MICs of EtBr and antibiotics were also measured in presence of protonophore, carbonyl cyanide m-chlorophenyl hydrazone (CCCP). Active efflux was assessed using ethidium bromide accumulation assays. Drug accumulation studies for fluoroquinolones were performed to determine the drug specificity of efflux. PCR was used to identify the mexAB-oprM gene in clinical isolates of P. AERUGINOSA. CCCP reduced the MICs of antibiotics at least in 1 dilution. Ethidium bromide accumulation assays confirmed the presence of proton gradient–dependent efflux mechanism in clinical isolates of P. AERUGINOSA and accumulation assays of fluoroquinolones showed that efflux systems in this bacterium extrude the structurally and functionally dissimilar antimicrobial agents. PCR demonstrated that 17% of clinical isolates of P. AERUGINOSA had the mexAB-oprM genes on the chromosome. This study indicates the presence of other RND efflux pumps, in addition to MexAB-OprM in multidrug resistance in clinical isolates of P .AERUGINOSA.

Background: PSEUDOMONAS AERUGINOSA is a gram negative non facultative bacterium and one of the members of normal flora in different sites of body in healthy humans. This bacterium can resist in fluids and hospital environments for a long time.PSEUDOMONAS AERUGINOSA has two systems for glucose uptake: a low affinity oxidative pathway and a high affinity phosphorylative pathway. The orf BCD genes are located over two million base pair upstream of the genes involved in the high affinity uptake system. Although the role of these genes are unknown by now, they may have a role in regulation of glucose uptake. In the present study, the role of orfD gene in glucose uptake in P.AERUGINOSA has been investigated.Method: orfD fragment were cloned in pUCP20 as vector and the recombinant plasmid transferred into WMA200 strain of P.AERUGINOSA, a mutant strain of P.AERUGINOSA with a chromosomal deletion of orfBCD. So we compared the rate of glucose uptake by P.AERUGINOSAWMA200, P.AERUGINOSAWMA200/pUCP20/orfD and P.AERUGINOSA H103 as wild type strain of P.AERUGINOSA by using labeled glucose under conditions at low substrate concentration and low cell density.Results: Carbohydrate uptake patterns differed considerably among three strains. The wild type is able to uptake glucose at a faster rate than the mutant; however, the mutant complemented with orfD shows an intermediate uptake comparing to the wild type and the mutant.Conclusion: orfD gene has an important role in carbohydrate uptake in P.AERUGINOSA strains however further studies are required to determine the involved mechanism.

PSEUDOMONAS AERUGINOSA is one of the most important opportunistic human pathogens. This bacterium is ubiquitous and exhibits innate resistance to a wide range of antimicrobial agents. The purpose of this study was to compare antimicrobial susceptibility patterns and plasmid profiles in hospital P.AERUGINOSA.During 8 months, 104 isolates of P.AERUGINOSA from different clinical (urine, blood, stool, sputum…) and environmental samples (sink, disinfectant solution, bed, hand,…) were collected. Susceptibility pattern of these isolates was obtained by disc diffusion (Kirby-Bauer) method. The alkaline lysis method was used for detection of plasmids.8% of 104 isolates of P.AERUGINOSA was environmental. Antimicrobial resistance was as follows: linkomycin (100%), ceftazoxime (99%), lomefloxacin (94%), ceftazidime (60%), ticarcillin (50%), ceftriaxone (44%) cefoperazone (37%), tobramicyne and ciprofloxacin10mg (35%), piperacillin and gentamicin (34%), carbenicillin (25%), ciprofloxacin30mg (24%), amikacin (22%), imipeneme (1%). All isolates were MDR but plasmids were detected in 29.8% isolates with 15 different plasmid profiles. The latter constituted 61.7% of total isolates which showed resistance to 10 or more antibiotics. There were specific correlations between some plasmid and resistance to antibiotics. The frequency of plasmids in P.AERUGINOSA was low (29.8%), indicating that the resistance genes are likely to be chromosomal. In spite of limitation of plasmid profiling, it is easy to perform and thus can be a useful method in epidemiological study.

Mastitis caused by P. AERUGINOSA is rare in cattle, but its isolation from environment is common. This infection usually originates from contaminated water used for udder washing. This pathogen colonizes in milking equipment; enter teats in milking intervals and causes mastitis under stressful conditions and poor hygine. Clinical mastitis due to P. AERUGINOSA is often severe with gangrene and death. Its subclinical and recurrent mild clinical mastitis can also be seen. In our study on 200 Holstein cows in Ahwaz, sterile milk samples from quarters with CMT positive were collected and sent to microbiology laboratory of Ahwaz Veterinary School for bacterial culture. From milk of two quarters with grade II of subclinical mastitis, P. AERUGINOSA like colonies grew. Conventional biochemical tests confirmed both isolates.    

Background: Scropholaria striata Boiss. From Scropholariaceae (Teshnehdari in folklore of Ilam Province, Iran) is used for treatment of infectious disease of urinary tract especially in females. Objective: In this research for finding of the most effective part of the plant, crude extract of the aerial parts of S. striata and its different fractions was investigated on the 50 resistant strains of Psudomonas aeroginosa. Methods: Crude extract of the plant and its various fractions (chloroform, methanol and water) were prepared. Bacterial strains were collected from 3 hospitals and 50 resistant strains were isolated from the culture medium containing various antibiotics. Efficacy of the all fractions was investigated on these resistant bacterial strains. Result: Water and methanol fractions of the plant were showed more antibacterial activity on 50 resistant strains of P. aeroginosa than crude extract (p=0. 0001 and p=0. 001 respectively) and water fraction was showed stronger effect than methanol fraction (p=0. 001). Chloroform fraction of the plant had no antibacterial activity on this resistant strain. Conclusion: The results of this study showed that the water extract of Scropholaria striata can be used as a remedy for the treatment of the infections caused by Psudomonas aeroginosa.

Rhamnolipids are among the best known biosurfactants and have been proven to be very promising in enhanced oil recovery, cosmetics, food and pharmaceutics. In this research, rhamnolipid production by PSEUDOMONAS AERUGINOSA NP2 in a bioreactorhas been investigated. This study shows that the PSEUDOMONAS AERUGINOSA NP2 is able to produce high quantities of rhamnolipid during 2.5 L batch bioreactor cultivations with sunflower oil as sole carbon source. The results showed that the maximum rhamnolipid concentration obtained was 13.5 g/L after 80 h of cultivation. The results also showed that the rhamnolipid production started at exponential growth phase and continued during the stationary phase. Two rhamnolipids, RL1 and RL3, produced by the microorganism, were confirmed by TLC and HPLC analysis. Finally, the produced rhamnolipid showed good surface activity because it is able to reduce the surface tension from 68 mN/m to 26 mN/m. Thus, PSEUDOMONAS AERUGINOSA NP2 could be an appropriate model for rhamnolipid production in pilot plant bioreactor systems.

Background and Objectives: Organophosphate pesticides are used most commonly for domestic, commercial, and agricultural purposes and have been found to be highly toxic. In essence, bioremediation has become one of the most important tools for removing these compounds in the environment, considering its higher efficiency when compared with the physicochemical methods.Materials and Methods: The biodegradation efficiency of two bacterial strains (i.e. Serratia marcescens BNA1 and PSEUDOMONAS AERUGINOSA BNA2) were assessed. In order to evaluate Malathion biodegradation, each sample was cultured on mineral salts medium containing Malathion as a sole carbon source. Malathion biodegradation efficiency of the strains was monitored in different culture media. The ability of bacterial isolates to degrade Malathion was studied using gas chromatography.Results: Serratia marcescens BNA1 and PSEUDOMONAS AERUGINOSA BNA2 were able to degrade Malathion. Biodegradation percentage in different treatments recorded were: BNA1+Ma (33.88%), BNA2+MA (26.45%), BNA1+BNA2+Ma (46.96%), BNA1+Ma+Tween (61.05%), BNA2+Ma+Tween (40.17%), and BNA1+BNA2+Ma+Tween (67.79%).Conclusion: It could be speculated that the best degradation efficiency can be yielded using mixture of strains plus a surfactant. The results of this study can be used in the bioremediation of Malathion contaminate soil after doing the pilot experiments.