ABSTRACT
Aims: This study was conducted to determine the effect of different doses of gamma radiation on Multi-drug resistant Pseudomonas aeruginosa isolated from River Nile at Rosetta branch and associated drains in Egypt. Place and Duration of Study: The study was started with samples collection in August 2010 through April 2011 in the Microbiology Dep., Central Laboratory for Environmental Quality Monitoring (CLEQM), National Water Research Center (NWRC), Cairo, Egypt and the National Centre for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority (EAEA), Cairo, Egypt. Methodology: Water samples were processed using membrane filtration, 144 strains of P. aeruginosa were isolated and identified and their antibiotic susceptibility was determined against 20 different antibiotics using agar disc diffusion method. Irradiation of bacterial isolates was processed using gamma irradiation unit of cobalt (Co60) and the D10-value was calculated from the survival curve. Results: Isolates were categorized as multi-drug resistant Pseudomonas aeruginosa (MDRPA). 125 (86.8%) were found to be extensively drug resistant (XDR) and 19 (13.2 %) were characterized as possible pan drug resistant (PDR). The highest resistance (100%) was mostly directed to amoxycillin/clavulanic acid, ampicillin, carbenicillin, methicillin, cephalothin, kanamycin, vancomycin, tetracycline, erythromycin, clindamycin, trimethoprim/sulfamethoxazole, nitrofurantoin and chloramphenicol. More than 75% of isolates were sensitive to norfloxacin (82.6%), piperacillin (81.2%), amikacin (79.2%) and tobramycin (77.8%). 63.2%, 26.4% and 14.6% of isolates were sensitive to ofloxacin, cefotaxime and ceftriaxone, respectively. The viable counts of MDRPA decreased with increasing radiation doses of gamma rays up to the lethal dose (3 kGy). The counts of 0.5, 1.0, 1.5, 2.0, 2.5 kGy irradiated samples were respectively 7.8, 6.5, 4.7, 2.3& 1 log10 and the D10-value calculated from the survival curve was 0.27 kGy. Conclusion: Contaminated fresh water may act as reservoirs for antibiotic resistant pathogens. Regular monitoring of Multi-drug resistant pathogens in aquatic environments should be adopted constantly. Gamma radiation demonstrates a potential value for wastewater treatment and pollution control.
Subject(s)
Africa South of the Sahara , Drug Resistance, Multiple, Bacterial/epidemiology , Drug Resistance, Multiple, Bacterial/radiation effects , Egypt , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/isolation & purification , Pseudomonas aeruginosa/radiation effects , Radiation, Ionizing , Rivers/microbiology , Wastewater/microbiology , Wastewater/therapyABSTRACT
Chromium pollution is produced in connection with industrial processes like in tanneries. It has been suggested that bioremediation could be a good option for clean up. The stress effect of variable chromate levels, pHs and growth temperatures on biochemical parameters of two Cr(VI) reducing bacterial strains Pseudomonas aeruginosa Rb-1 and Ochrobactrum intermedium Rb-2 was investigated. Transmission electrone microscopy (TEM) was performed to study the intracellular distribution of Cr(VI). It was observed that initial stress of 1000 µgmL-1 caused significant enhancement of all studied biochemical parameters at pH 7.0 and growth temperature of 37 °C showing great bioremediation potential of the strains. Transmission electron microscopy revealed that the distribution of chromium precipitates was not uniform as they were distributed in the cytoplasm as well as found associated with the periplasm and outer membrane. Fourier transform infrared spectroscopy showed the possible involvement of carboxyl, amino, sulpohonate and hydroxyl groups present on the bacterial cell surface for the binding of Cr(VI) ions. Cr(VI) stress brought about changes in the distridution of these functional groups. It can be concluded that the investigated bacterial strains adjust well to Cr(VI) stress in terms of biochemical parameters and along that exhibited alteration in morphology.
Subject(s)
Chromium/metabolism , Ochrobactrum/metabolism , Pseudomonas aeruginosa/metabolism , Stress, Physiological , Chromium/toxicity , Cytoplasm/ultrastructure , Environmental Pollutants/metabolism , Environmental Pollutants/toxicity , Hydrogen-Ion Concentration , Microscopy, Electron, Transmission , Oxidation-Reduction , Ochrobactrum/drug effects , Ochrobactrum/radiation effects , Ochrobactrum/ultrastructure , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/radiation effects , Pseudomonas aeruginosa/ultrastructure , Spectroscopy, Fourier Transform Infrared , Surface Properties , TemperatureABSTRACT
Pseudomonas aeruginosa and Staphylococcus aureus are important pathogens that produce wide spread infections. Purpose of this study was to evaluate the antimicrobial effect of ultrasonic irradiation [US] alone and in combination with antibiotic on antibiotic resistance Pseudomonas aeruginosa and Staphylococcus aureus. In this study ultrasonic irradiation [US] in a laboratory-scale batch sonoreactor with low frequency [42 kHz] plate type transducer at 170W of acoustic power was used. The Water samples, were taken from different wards of the 3 teaching hospitals which were affiliated to the Kurdistan University of Medical Sciences to isolate Pseudomonas aeruginosa and Staphylococcus aureus and also to determine their antimicrobial susceptibility pattern. Our results showed that Pseudomonas aeruginosa and Staphylococcus aureus were affected by the ultrasound and the bactericidal effect increased with time. It was found that P. aeruginosa was more susceptible to the ultrasonic treatment than S. aureus. The combination of US with an antibiotic [amoxicillin] enhanced killing of both bacteria over the use of US alone. There were no differences in resistance to ultrasound between isolated strains and standard strains from Persian type culture collection