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Background & Objective: in recent years antibiotic resistance of Pseudomonas aeruginosa is increased as a causetive factor in hospital contamination. This study was done to determine the prevalence and antibiotics susceptibility of Pseudomonas aeruginosa isolated from inanimate objects in Taleghani hospital.

 

Materials & Methods: This descriptive study was done on inanimate objects in different wards of Taleghani hospital during 2006. Sampling was performed by sterile gauze pad for dry surfaces and swab for wet surfaces. To differentiate and identify P.aeruginosa, various culture media such as Brain Heart Infusion Agar, Citrimide Agar and Triple Sugar Iron Agar were used. Antibiotic sensitivity of the isolated strains was determined by Kirby-Bauer Method using Muller-hinton Agar medium. Moreover, antiseptic sensitivity of the strains to Decosept and Povidone-Iodine as the main antiseptic agents was identified by determining Minimal Bactericidal Concentration and Minimal Inhibitory Concentration using Nutrient Agar and Nutrient Broth media.

 

Results: Fifty-five of the total 292 samples were positive for P.aeruginosa. Based on the ratio of the number of positive samples to the total samples, Thalassemia ward (38.5%) was the most infected ward and taps (61.1%) was the most infected sampling place. None of the samples from room atmosphere and intensive care equipments were positive for P.aeruginosa. 20% of the samples were resistant to ceftazidime and 32.7% were resistant to piperacillin, also 10.9% of samples were resistance to both ceftazidime and piperacillin.

 

Conclusion: This study showed that contamination with P.aeruginosa and antibiotic resistance of the isolated bacteria are the main problems in Taleghani hospital.

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Background and Objective: Pseudomonas aeruginosa is one of the important causes of nosocomial infections. Extended spectrum-beta Lactamases (ESBLs) and Metallo-beta Lactamase (MBL) producing strains have become resistant against a wide range of antibiotics. The aim of this study was to determine the effect of Methanol extract of Camellia Sinensis on Pseudomonas aeruginosa producing ESBL isolated from burnt wounds of patients.

Materials and Methods: This descriptive study was done on burnt wounds of 245 hospitalaized patients in Shafa hospital, Kerman, Iran during 2006-07. ESBLs producing strains were detected by phenotypic confirmatory test and also E-test strips were used for MBL detection. P.aeruginosa MIC was determined for Cefotaxime, Ceftazidime, Azteronam, Imipenem, Meropenem and methanol extracts of plant Camellia Sinensis prepared by Maceration method.

Results: 120 of burnt wound infected with P.aeruginosa, out of them 41 isolates contained ESBL while lacked MBL. 60% of isolates were resistant to Cefotaxime, 66% to Ceftazidime, 42% to Azteronam, 3% to Imipenem and 5% to Meropenem. Among the extracts, green Tea had the highest antibacterial effect on standard strains and P.aeruginosa producing ESBLs in 1.25mg/ml concentration.

Conclusion: This study showed that methanolic extract of green tea has higher antibacterial effect aginst β-lactamase P.aeruginosa strains than Cefotaxime and Ceftazidime.

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Background and Objective: Ferula gummosa Boiss. (Barije.) contain medical and antimicrobial properties. This study was done to determine the effect of aqueous and alcoholic extracts of roots of Ferula gummosa Boiss. on the growth of Pseudomonas aeruginosa. Materials and Methods: In this laboratory study, the plant was dried in dark place and aqueous, alcoholic extracts of Barije's root, powder were prepared using Soxhlet method. The efficacy of 0.1 dilution of different values of extracts of Ferula gummosa Boiss. on the strain of Pseudomonas aeruginosa (PTCC 1430) were evaluated by disk diffusion, Agar-well diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Results: Pseudomonas aeruginosa was completely resistant to the aqueous extract, and the MIC for the methanol and ethanol extracts was 1.25×10⁴ μg/ml and 6.25×10³ μg/ml, respectively. Conclusion: Methanolic and ethanolic extracts of Ferula gummosa Boiss. have antimicrobial activity against Pseudomonas aeruginosa in in-vitro model.

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Background and Objective: Polycyclic Aromatic Hydrocarbons (PAHs) are the most important organic pollutants that causing multiple side effects including carcinogenic, mutagenic and toxicity. Among the aromatic compounds degrading bacteria, pseudomonas produce board spectrum of degrading enzymes and are used, as biological tools, for decreasing of PAHs. This study was done to evaluate the degradation of polycyclic hydrocarbones anthracene by using Pseudomonas aeruginusa.

Methods: In this descriptive – analytic study, sampling was collected from river estuary sediment and had cultured in Minimal Salt Medium (MSM). Pseudomonas aeruginosa was one of the isolated bacteria from river sediment which identified by molecular technique. In next step, influence of pH (6.5 and 7.5) temperature (25 and 35°C) and concentration of anthracene (150 and 200 ppm) were surveyed on anthracene biodegradation and bacterial growth during zero, 24 and 48 hours by HPLC and spectrophotometry method respectively.

Results: The results showed that the optimized condition for biodegradation included pH=7.5, 35°C and 150 ppm of anthracene. Bacterial degradation of anthracene was increased with prolong of incubation time. Biodegradation efficiency of anthracene in the presence of pseudomonas was 50% within 2 days, which indicates the ability of the bacteria for the enzymes production.

Conclusion: High growth potential of pseudomonas in unsuitable areas and due to the production of degrading enzymes, it can be used as indicator bacteria used to remove anthracene.

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Background and Objective: Pseudomonas aeruginosa is an opportunistic pathogen with numerous virulence factors such as phospholipase and type IV pili. The emergence of multidrug resistant Pseudomonas aeruginosa has become a serious public health threat worldwide. This study was done to determine the frequency of plcH, plcN, pilA and pilB genes in multi-drug resistant Pseudomonas aeruginosa isolated from clinical samples.

Methods: In this cross-sectional study, 93 isolates of Pseudomonas aeruginosa collected from different clinical samples from hospitals of Zanjan, Iran during 2013-14. After identification of isolates by biochemical tests, antibiotic susceptibility testing (Kirby-Bauer) was performed according to CLSI guidelines. Total DNA extracted and PCR was done to detect of plcH, plcN, pilA and pilB genes.

Results: Among 93 of Pseudomonas aeruginosa isolates, the highest antibiotic resistance related to Erythromycin and Cefoxitin (95.6%) and the lowest resistance related to Amikacin (26.8%). 80.6% of isolates were multidrug resistant (MDR). Out of 75 MDR isolates, the frequency of plcH, plcN, pilA and pilB genes was 97.4%, 49.3%, 26.6% and 17.3%, respectively.

Conclusion: According to high frequency of phospholipase C gene (plcH) in MDR Pseudomonas aeruginosa isolates which isolated from different clinical samples, presumably this virulence factor plays an important role in pathogenesis of this bacterium.

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Background and Objective: Biofilms caused by pathogenic microorganisms that plays an important role against human health. Due to their resistance to detergents and antimicrobial agent, treatment response of affected patients with these bacteria is difficult. This study was done to evaluate the effect of methanol extract of Nasturtium officinale plant on growth and biofilm formation of Pseudomonas aeruginosa.
Methods: In this descriptive - laboratory study, the extraction was done by Maceration in 80% methanol and by rotary evaporator. The minimum inhibitory concentration (MIC) of Nasturtium officinale extracts were determined by broth microdilution method. Biofilm formation was investigated using the microtiter plate and stained with crystal violet.
Results: The minimum inhibitory concentration of Nasturtium officinale against Pseudomonas aeruginosa was 0.625 mg/ml and the Minimum bactericidal concentration of this extract was 1.25 mg/ml. PAO1 strain and 5 clinical strains were able to biofilm formation. Inhibition of biofilm formation by extract of Nasturtium officinale plant was dependent to concentration. The highest percentage of inhibition of biofilm formation was in the concentration of 7.5 mg/ml and the lowest percentage of inhibition of biofilm formation was in the concentration of 0.11 mg/ml. The mean of Pseudomonas aeruginosa biofilm inhibition by Nasturtium officinale extracts was 72.69±22.27 %. In the concentrations of 7.5, 0.93, 0.46, 0.23 and 0.11 mg/ml, there was a significant difference between clinical strains and PAO1 strain (P<0.05).
Conclusion: Methanolic extracts of Nasturtium officinale plant has anti-bacterial and anti-biofilm effect against Pseudomonas aeruginosa.

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Background and Objective: The ever-increasing resistance to beta-lactame antibiotic in opportunistic Pseudomonas aeruginosa bacteria considered as one of the important factors of death of hospital-acquired infections. This study was performed for determine the antibiotic resistance and prevalence of IMP-1 and VIM-1 metallo-beta-lactamase and integron class I genes in clinical isolates of Pseudomonas aeruginosa.
Methods: In this descriptive-analytical study, 200 Pseudomonas spp. isolates from blood, urine, ulcer, eye and sputum infections were collected from Arsanjan hospital in Fars province in south –west of Iran during April-September 2016. After confirmation genus of bacterial by biochemical and 16S rRNA tests, and isolation of Pseudomonas aeruginosa by specific primer of lasI Gene, antibiotic susceptibility was done according to diffusion disk assay and CLSI procedure, the presence of blaVIM, blaIMP and Int-1 genes were determined by PCR.
Results: The results of phenotypic and genotypic tests led to the isolation of 107 isolates of Pseudomonas aeruginosa that the highest resistance with (79.38%) for cefepime and the lowest resistance with (13.08%) for tobramycin. Out of 107 isolates, 10 (9.35%) isolates were carrying class1 Integron,19 (17/76%) isolates carrying IMP gene, 23 (21.5%) isolates carrying VIM gene, 4 (3.74%) isolates carrying IMP gene and integron class1, 11 (10.28%) isolates carrying VIM gene, and class1 intgron, 15 (14.02%) isolates carrying both IMP, VIM and 12 (11.22%) isolates simultaneously were carrying each three genes, VIM, IMP and class1 integron. 13 (12.15%) isolates did not have none of these three genes, VIM, IMP, class1 integron.
Conclusion: The results showed increased multidrug resistance and simultaneous presence of one or two IMP, VIM and Int-1 genes in Pseudomonas aeruginosa strains. Int-1 has the ability to transduce resistance genes and create resistant populations.

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Background and Objective: Pseudomonas aeruginosa is an opportunistic pathogen that is a major cause of mortality in immunocompromised patients. One of the most important mechanisms of resistance of this bacterium is biofilm formation. The aim of this study was done to determine the Effect of Morin on Expression of Biofilm Gene of Pseudomonas aeruginosa Isolated from burn wounds by Real time PCR.
Methods: In this descriptive-analytic study 60 sample were collected from burn wounds of patients admitted to the hospitals in Tehran, Iran. Samples were identified by using biochemical methods. The DNA of the isolates was extracted and then antimicrobial activity of morin analyzed by microbroth dilution assay. The presence of biofilm production genes was investigated by PCR. Finally, the expression of lasI gene in combination with Sub-MIC concentration of morin in biofilm-producing bacteria was evaluated using Real time PCR.
Results: From 60 samples that analyzed by Multiplex-PCR, 12 (20%) Pseudomonas aeruginosa strains were isolated in which 12 isolates (100%) were carried lasI and lasR, genes, respectively. 3 isolates (25%) were carried rhlI gene. Sub-MIC concentration of morin in biofilm-producing bacteria reduced lasI gene expression in Pseudomonas aeruginosa.
Conclusion: Morin has significant efficacy on Pseudomonas aeruginosa and could be a good alternative for treatment of antibiotic resistant isolates.

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Background and Objective: Binding of antibiotics to nanoparticles increases the antibacterial potential of nanoparticles and antibiotics. This study was performed to determine the antibacterial and hemolytic effect of zinc / ferrite / cellulose nanocomposite (ZnFe2O4 @ Cell) (single nanoparticle), zinc / ferrite / cellulose nanocomposite was aminated with 3-aminopropyltriethoxysilane (APTES) with the name of ZnFe2O4@Cell@APTES (Coated nanocomposite) and ZnFe2O4@Cell@APTES@Van nanocomposite (coated nanocomposite bound to vancomycin) against gram-negative bacteria Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) and gram-positive bacterium Staphylococcus aureus (S. aureus).
Methods: In this descriptive study, antibacterial-activity was evaluated by broth macro dilution method. Minimum inhibitory concentration (MIC) and minimum lethal concentration (MBC) were determined for E. coli, S. aurous and P. aeruginosa. The hemolytic activity of nanoparticles was investigated by colorimetric method.
Results: Nanoparticles did not have hemolytic activity. ZnFe2O4@Cell and ZnFe2O4@Cell@APTES@Van did not have a significant antibacterial effect against gram-positive and gram-negative bacteria, and vancomycin binding resulted in antibacterial-activity. ZnFe2O4@Cell@APTES@Van inhibited the growth of Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. The growth of E. coli was reduced to 85% at a concentration of 0.4 mg/ml and a concentration of 0.1 mg nanoparticles completely prevented the growth of P. aeruginosa. The growth of gram-positive S. aureus bacteria at a concentration of 0.3 mg/ml nanoparticles was completely stopped.
Conclusion: Vancomycin-modified nanocomposite has antibacterial-activity against both gram-positive and gram-negative bacteria and has the potential to overcome the antibiotic resistance of bacteria.