Resistant Strains Of Pseudomonas Research Articles

Study of Copper Resistant Pseudomonas Strains Isolated from Soil in Sarcheshmeh Copper Mine, in Iran and Investigation of the Mechanisms Involved in Copper Resistance

Heavy metal contaminated sites are the potential source of metal resistance microorganisms. The major focus of this study is to isolate and identify copper ions resistant Pseudomonas from the soil samples collected from mining and refining sites of Sarcheshmeh copper mine in the Kerman Province of Iran and investigate on possible mechanisms for copper resistance. Isolates were selected based on high level of copper ions resistance. The screened isolate was identified as Pseudomonas putida Cu-2 by morphological, biochemical and 16S rDNA gene sequencing analysis. A high degree of copper ions resistance associated with multiple antibiotic resistances was also detected in the screened isolate. The growth pattern of screened isolate with all the studied Cu concentrations was similar to that of control (without Cu ions) indicating that Cu ions would not affect the growth of isolated strain. A decrease in the amount of exopolysaccharides (EPS) was detected after Cu ions – P. Putida Cu-2 culture supernatant interaction. The Fourier transform infrared spectroscopy (FT-IR) peaks for the EPS extracted from the bacterial culture supernatant and the interacted Cu ions were nearly similar. The EPS covering of the Cu ions was established by FT-IR. The study of bacterial EPS covered Cu ions with E. coli PTCC 1338 and S. aureus PTCC 1113 exhibited less toxicity compared to uncoated Cu ions. The presence of copA gene that encodes for the multi-copper oxidase was investigated in the selected strain. The present study suggests that the capping of Cu ions by bacterially produced EPS and the presence of copA gene serve as the probable mechanisms of copper resistance.

Antibacterial activity potential of leaf extracts of Blepharis maderaspatensis and Ziziphus oenoplia against antibiotics resistant Pseudomonas strains isolated from pus specimens

Knowing the antibiotic resistance profile of pathogenic bacteria is essential to finding an appropriate remedy for these issues by sourcing antibacterial agents from plants. The present study exposes the bactericidal potential of different leaf extracts of Blepharis maderaspatensis and Ziziphus oenoplia against multi drug resistant bacterial strains enumerated from pus specimens at a secondary care medical centers from Namakkal region. The Pseudomonas sp. >Staphylococcus sp. >Klebsiella sp. >Escherchia sp. >Enterococcus sp. >Micrococcus sp. strains were found as most prevalent bacterial pathogens. Moreover, that about four bacterial isolates namely P. aeroginosa CM1-CM4 identified by 16S rRNA sequencing were shown tolerance to additional various antibiotics. In a combined approach (50 μL + 50 μL), methanol extracts of both B. maderaspatensis and Z. oenoplia were more effective than individual and other solvent extracts against P. aeroginosa CM1-CM4 strains. This shows among the rapid development of antibiotic-resistant pathogens this B. maderaspatensis and Z. oenoplia (methanol extract) might act as a medication in the future.

A comparative study of Kigelia pinnata fruit extracts in terms of antimutagenic potential and antimicrobial efficacy against antibiotic-resistant microbial strains

In recent years, antibiotic-resistant microbes have become a serious concern which needs proper attention either to solve the problem or to find out the solution to treat it. In this study, antibiotic resistant strains of Pseudomonas, Enterococcus, and Escherichia coli (E. coli) were used to assess the antimicrobial potential of Kigelia pinnata fruit extract. Further, antimutagenic potential of Kigelia pinnata fruit extract was also assessed by Ames assay using Salmonella typhimurium strain TA 98 and TA 100. In antimicrobial assay, only chloroform, ethanol and hexane extract was found to produce clear zone diameter between 1.08±0.1 to 2.1±0.2 mm. Results of minimum inhibitory concentration revealed the effectiveness of chloroform extract on Pseudomonas, Enterococcus and E.coli at 1.8 mg/mL concentration. However, better antimicrobial activity was found with ethanol extracts at 2.1x10-2 mg/mL concentration revealing the effectiveness of the low dose of ethanol in killing the antimicrobial resistant strains. In the time-kill test method, chloroform extract of K. pinnata was found to be most effective in reducing 98-99% test microbial population at both dilutions in 30 min. Antimutagenicity test showed the equal potential of chloroform and ethanol extracted Kigelia fruit sample in reducing the number of revertants. Kigelia fruit extract (1000 μL) dose can reduce the mutagens at 5 μg/plate level but not at 10 μg/plate dose level. Further research will open the new scope in the field of development of herbal antimicrobials and antimutagenic compound for treating antibiotic-resistant microbes and cancer.

Hospital wastewater: reservoir of antibiotic resistant pseudomonas strains in Ibadan, Nigeria

Hospital wastewater: reservoir of antibiotic resistant pseudomonas strains in Ibadan, Nigeria

PCR based DNA fingerprinting of mercury resistant and nitrogen fixing Pseudomonas spp.

Mercury resistant Pseudomonas strains were isolated from polluted water, rhizospheric soil and root nodules of different plant species. Selected bacterial isolates showed potential to produce florescence under UV light and to tolerate heavy metal stress of 10-20 µg/ml HgCl2. Biochemical characterization revealed all selected bacterial isolates belong to genus Pseudomonas. A total of 27 bacterial isolates were evaluated for bioremediation of mercury due to their ability to produce H2S and fix nitrogen. Genomic DNA of 12 Pseudomonas strains was isolated and their genetic diversity was evaluated using SSR (GACA)4 microsatellite finger printing. On the basis of banding pattern of PCR amplified products, a phylogenetic tree was constructed using Minitab 13 software which showed 71%, 46% and 44% homology of SZ-30, SZ-6 and SZ-8 with strains of cluster 1 and SZ-16 respectively. Results exhibited significant diversity among selected Pseudomonas strains.

Isolation of copper oxide (CuO) nanoparticles resistant Pseudomonas strains from soil and investigation on possible mechanism for resistance

The present study deals with isolation and characterization of copper oxide nanoparticles resistant Pseudomonas strains that were isolated from the soil collected from mining and refining sites of Sarcheshmeh copper mine in the Kerman Province of Iran. The three isolates were selected based on high level of copper oxide nanoparticles (CuO NPs) resistance. The isolates were authentically identified as Pseudomonas fluorescens CuO-1, Pseudomonas fluorescens CuO-2 and Pseudomonas sp. CuO-3 by morphological, biochemical and 16S rDNA gene sequencing analysis. The growth pattern of these isolates with all the studied CuO NPs concentrations was similar to that of control (without CuO NPs) indicating that CuO NPs would not affect the growth of isolated strains. A reduction in the amount of exopolysaccharides was observed after CuO NPs-P. fluorescens CuO-1 culture supernatant interaction. The Fourier transform infrared spectroscopy (FT-IR) peaks for the exopolysaccharides extracted from the bacterial culture supernatant and the interacted CuO NPs were almost similar. The exopolysaccharide capping of the CuO NPs was confirmed by FT-IR and X-ray diffraction analysis. The study of bacterial exopolysaccharides capped CuO NPs with E. coli PTCC 1338 and S. aureus PTCC 1113 showed less toxicity compared to uncoated CuO NPs. Our study suggests that the capping of nanoparticles by bacterially produced exopolysaccharides serve as the probable mechanism of tolerance.

Effect of multiple metal resistant bacteria from contaminated lake sediments on metal accumulation and plant growth

Naturally occurring bacteria play an important role in bioremediation of heavy metal pollutants in soil and wastewater. This study identified high levels of resistance to zinc, cesium, lead, arsenate and mercury in eight copper resistant Pseudomonas strains previously isolated from Torch Lake sediment. These strains showed variable susceptibility to different antibiotics. Furthermore, these metal resistant strains were capable of bioaccumulation of multiple metals and solubilization of copper. Bacterial strains TLC 3-3.5-1 and TLC 6-6.5-1 showed high bioaccumulation ability of Zn (up to 15.9 mg/g dry cell) and Pb (80.7 mg/g dry cell), respectively. All the strains produced plant growth promoting indole-3-acetic acid (IAA), iron chelating siderophore and solubilized mineral phosphate and metals. The effect of bacterial inoculation on plant growth and copper uptake by maize ( Zea mays) and sunflower ( Helianthus annuus) was investigated using one of the isolates ( Pseudomonas sp. TLC 6-6.5-4) with higher IAA production and phosphate and metal soubilization, which resulted in a significant increase in copper accumulation in maize and sunflower, and an increase in the total biomass of maize. The multiple metal-resistant bacterial isolates characterized in our study have potential applications for remediation of metal contaminated soils in combination with plants and metal contaminated water.

Synthesis, characterization and antibacterial activity of cobalt(III) complexes with pyridine–amide ligands

The ligands 2-( N-( X-pyridyl)carbamoyl)pyridine ( X = 2, 3 or 4 for HL 1–HL 3, respectively) and 2,6-bis( N-( Y-pyridyl)carbamoyl)pyridine ( Y = 2, 3 or 4 for H 2L 4–H 2L 6, respectively) in their mono- and di-deprotonated forms have been used to synthesize kinetically stable cobalt(III) compounds [Co(L 1–3) 3] ( 1– 3) and Na[Co(L 4–6) 2] ( 4– 6), respectively. The Co(III) ion is in octahedral environment and is surrounded by three bidentate ligands in complexes 1– 3 and two tridentate ligands in complexes 4– 6. Ligands coordinate the cobalt center via amidic- N and pyridine- N centers forming a 5-membered chelate ring. Complexes 1– 6 have thoroughly been characterized by the various spectroscopic analyses ( 1H NMR, 13C NMR, UV–vis, IR, mass), elemental analysis, and conductivity measurement. All complexes have been assayed for in vitro antimicrobial activity against clinically isolated resistant strains of Pseudomonas, Proteus, Escherichia coli and standard strains of Pseudomonas aeruginosa (MTCC 1688), Shigella flexneri (MTCC 1457), Klebsiella planticola (MTCC 2272). All cobalt compounds show mild to moderate activity. However, complexes [Co(L 1) 3] ( 1) and Na[Co(L 4) 2] ( 4) were found to have potent activity against standard and pathogenic resistant bacteria used in the study. Their MIC ranged from 2.7 to 187 μg/ml. In vitro toxicity tests demonstrated that all complexes were less cytotoxic than that of gentamycin on HEK cell lines and the results reveal that these complexes can act as potent antimicrobial agents.

Removal of Mercury from Chemical Wastewater by Microoganisms in Technical Scale

The enzymatic reduction of Hg(II) to water insoluble Hg(0) by mercury resistant bacteria has been used for removal of mercury from wastewater in technical scale. Pure cultures of seven mercury resistant strains of Pseudomonas were immobilized on carrier material inside a 700 L packed bed bioreactor. Neutralized chloralkali electrolysis wastewater with a mercury concentration of 3−10 mg/L was continuously fed into the bioreactor (0.7 m3/h up to 1.2 m3/h). A mercury retention efficiency of 97% was obtained within 10 h of inoculation of the bioreactor. At optimum performance, bioreactor outflow concentrations were below 50 μg Hg/L, which fulfill the discharge limit for industrial wastewater. In combination with an activated carbon filter, outflow concentrations below 10 μg Hg/L were always obtained. The retention efficiency of the bioreactor was not affected by fluctuations in inflow conductivity (between 20 and 105 mS/cm), pH (between 6.5 and 7.5), or mercury concentration (between 3 and 10 mg/L) and was be...

Synergism between tobramycin and ceftazidime against a resistant Pseudomonas aeruginosa strain, tested in an in vitro pharmacokinetic model.

Synergism between two antibiotics is usually tested by a checkerboard titration technique, or by time-kill methods. Both methods have the disadvantage that synergism is determined at constant concentrations of the antibiotics, which do not reflect reality in vivo. In the present study we determined whether synergism between tobramycin and ceftazidime can be found at declining concentrations below the MIC, and whether change in dosing sequence of the antibiotics would result in differences in killing. Three monotherapy and six combination therapy schedules were tested in an in vitro pharmacokinetic model, using a Pseudomonas aeruginosa resistant to both antibiotics. During all q8h dosing schedules the peak concentration (Cmax) was adjusted to the MIC for the strain of both antibiotics. During all monotherapy regimens bacterial growth was present, while all six combination therapy schedules showed significant killing. At t = 24 h there were no differences between all combination therapy schedules, but at t = 8 h the two combination therapy schedules with administration of tobramycin once daily showed a significantly faster killing. By using the area under the killing curve (AUKC) as a parameter for synergistic killing, simultaneous combination therapy starting with tobramycin once daily was significantly better than all other regimens. We conclude that there is synergism between tobramycin and ceftazidime at declining antibiotic concentrations below the MIC, resulting in a pronounced killing of a resistant Pseudomonas strain. Infections due to resistant Pseudomonas strains could possibly be treated by a synergistic combination of these drugs.

Aqueous kinetics of sisomicin sulphate.

Sisomicin sulphate is a new-generation aminoglycoside with a broad spectrum of antimicrobial activity that includes Pseudomonas aeruginosa. It is superior to gentamicin against indole-negative Proteus and some resistant strains of Pseudomonas. The ocular pharmacokinetics of sisomicin have not been explored. We used the agar diffusion technique of microbial assay to determine the aqueous penetration and bioavailability of a subconjunctivally placed standard dose of 20 mg/0.4 ml of sisomicin sulphate in 20 human volunteers undergoing elective cataract surgery. A peak concentration of 16.4 mg/l was found in the aqueous humour 78 minutes after injection, which is 65 times the minimum inhibitory concentration for Pseudomonas. The antibiotic was bioavailable up to 1203 minutes after injection in a concentration of 0.9 mg/l, which easily covers the minimum inhibitory concentration of Staphylococcus aureus and Pseudomonas. The antibiotic disappears from the aqueous humour at the 1434 minute interval (approximately 24 hours). The elimination half-life (t1/2 of sisomicin was determined to be 5.16 hours (K = 0.134/hour) and the aqueous clearance was 2.87 microliters/min.

Oral treatment of Pseudomonas-induced urinary tract infections with ciprofloxacin.

In an open study, a group of 11 patients with asymptomatic urinary tract infections, caused by resistant Pseudomonas strains, were given 200 mg of ciprofloxacin per day for 1 week. All strains displayed an in vitro sensitivity to the drug. Complete clinical resolution was obtained in 8 patients and long-term eradication in 3. No adverse reactions and only minor and reversible laboratory changes were recorded. Ciprofloxacin could be a valuable oral drug in the treatment of severe urinary infections. However, more clinical studies on the development of resistance under therapy and with other dose schedules are indicated.

Control of burn wound infections by pefloxacin and its silver derivative

As might be anticipated, strains of Pseudomonas aeruginosa resistant to silver sulfadiazine have appeared. We have found an analogue of nalidixic acid (pefloxacin) which, along with its silver derivative, is highly effective against these resistant strains. In vitro the minimal inhibitory concentrations are 10 to 20 times lower than that of silver sulfadiazine against bacteria. In burned mice and rats infected with silver sulfadiazine resistant pseudomonas strains, mortality in groups receiving topical therapy with pefloxacin and silver pefloxacin is about 10 per cent compared to 80 per cent with silver sulfadiazine (100 per cent in untreated controls). There is little systemic absorption of pefloxacin and no absorption of silver from topical treatment. In addition, silver pefloxacin exhibits higher antifungal activity in vitro.

Inactivation of chloramphenicol by gram-negative microorganisms.

Two derivative strains of Escherichia coli with high-level resistance to chloramphenicol, one carrying an episomal resistance factor and the other a chromosomal mutant, were both shown to be potent inactivators of the drug. When 1 mM chloramphenicol was added to an exponential culture in minimal medium, growth was halted until 85–90% of the drug was inactivated by acylation. At this state the drug was essentially monoacylated. During and after growth, esterification of the second alcoholic group occurred, though at a slower rate. Arylamines, in amounts up to 10% of chloramphenicol equivalents, were demonstrated in the growth medium after 1–3 days' incubation.With an acetateless mutant of Escherichia coli K12, carrying a resistance factor, it was shown that 5–6 moles of acetate was consumed for every mole of chloramphenicol acylated.Inactivation of chloramphenicol by Gram-negative organisms from infections in hospitalized patients was also examined. Among 103 strains susceptible to chloramphenicol, none produced considerable amounts of chloramphenicol esters. The same was the case with 14 resistant strains of Pseudomonas. Of 134 other resistant organisms examined, including strains of Escherichia, Proteus, Klebsiella, Salmonella, and Shigella, 133 were producers of chloramphenicol esters, and in most cases the drug was partly or entirely diacylated.

食品防腐剤に関する研究-VII

The organisms causing a type of deterioration of fish sausage by forming spots on the surface of fish sausage during storage were found to be B. coagulans by YOKOZEKI3) of the Tokai Regional Fisheries Research Station. It was also disclosed by the present authors4) that these organisms were highly resistant to nitrofurazone (NFS), a food preservative being permitted legally in Japan for keeping the quality of fish paste products such as “kamaboko”. According to OKA6), 7), the mechanism of growth inhibitory action of NFS to the NFS susceptible organisms might be due to the reduction of nitro-group in the NFS molecule, whereas, certain resistant organisms seemed to be poor or sometimes lacking in reducing ability for the furan compound. On the other hand, AMANO2) has reported that Pseudomonas fluo-rescens, one of the principal putrefactive organisms of raw fish, has a character to reduce nitro-group in the NFS molecule actively, and he concluded that the insensitivity of Pseudo-monas to NFS might be attributable to the rapid reduction of NFS in the medium. In the present study, comparison in the mode of destruction of NFS was carried out with 3 different types of organisms; the aforementioned NFS resistant strains of B. coagulans, NFS resistant strains of B. coagulans, NFS susceptible spore forming bacilli including sensitive B. coagulans, and naturally occurring NFS resistant strains of Pseudomonas and and Micrococcus. Results obtained may be summarized as follows: 1. In a peptone medium containing NFS, the fish sausage deteriorating organisms of B. coagulans kept a high level of residual NFS in the medium even after 1 week of incubation (Fig. 1), to the contrary, the susceptible bacilli and resistant Pseudomonas and Micrococcus decomposed NFS completely within a period of 2 to 3 days (Figs. 2 and 3). 2. This tendency has become more valid when the experiments using washed cells sus-pension of these organisms were conducted, viz., no appreciable reduction of NFS occurred in the cells of resistant B. coagulans, while rapid reduction was noted either in the suscep-tible B. coagulans or in the resistant Pseudomonas (Table 1). 3. These findings mentioned above may suggest the necessity of further detailed studies on the mechanism of nitrofurazone resistance by certain type of bacteria.