Browsing by Subject "biofilms"

Now showing 1 - 4 of 4
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    Does Magnesium Transport Protein (MgtE) Contribute to the Antibiotic Resistance of Pseudomonas aeruginosa?
    (Office of the Vice Chancellor for Research, 2013-04-05) Umwali, Audrey; Anderson, Gregory G.
    Pseudomonas aeruginosa is an environmental and opportunistic bacterial pathogen that is resistant to antibiotic treatment when it forms biofilms in the lungs of patients with cystic fibrosis. Biofilms are densely packed communities of bacteria embedded within a self-produced matrix of extracellular polymeric substance (EPS). Biofilm EPS is a polymeric cluster composed of extracellular DNA, proteins and polysaccharides. Based on previous studies, in a low Mg2+ environment, P. aeruginosa wild-type is less or non-resistant to antibiotics and in a high Mg2+ environment, P. aeruginosa is more resistant to antibiotics. The purpose of this project was to find out if the magnesium transport protein (MgtE) is a contributor to the antibiotic resistance of P. aeruginosa .This was accomplished by using two different strains of P.aeruginosa; PA14 wild-type and GGA52 mutant (without the magnesium transporting protein). Four antibiotics were used; gentamicin, tobramycin, ciproflaxin and imipenem. The minimum inhibitory concentration (MIC) of each antibiotic was determined by culturing the bacteria strains on LB agar plates and use Etest strips to observe growth. N-minimal media supplemented with varying magnesium concentration was used to test if Mg2+ increased or reduced the antibiotic resistance at the MIC of P. aeruginosa as well as counting bacterial colonies. The mutant strain (GGA52) is expected to be less resistant than the wild type strain (PA14) because it does not have MgtE. If these predictions are true, then MgtE is an important contributor to the antibiotic resistance of P. aeruginosa. These results can be helpful in understanding the mechanism of antibiotic resistance of P. aeruginosa in patients with cystic fibrosis.
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    THE EFFECTS OF QUORUM SENSING ANTAGONISTS ON BIOFILM
    (Office of the Vice Chancellor for Research, 2012-04-13) Guzman, Juan M.; Anderson, Gregory G.
    Cystic fibrosis (CF) is a recessive genetic disorder that causes the for-mation of thick mucus plugs in the lungs of approximately 30,000 people in the United States and 60,000 individuals world-wide. Pseudomonas aeruginosa, an opportunistic bacterial pathogen, is able to colonize the mu-cus plugs and form antibiotic resistant biofilms. These microbial colonies, known as biofilms, cause serious problems for individuals living with CF. P. aeruginosa biofilms are able to cause chronic infections in the lungs of CF patients leading to increased morbidity and mortality. Using a modified bio-film assay, we tested the effects of modified chemical compounds and amino acids on P. aeruginosa biofilm dispersion. A previous study performed on P. aeruginosa, found that treatment of d- and l- amino acids resulted in biofilm dissemination. Through additional experiments, we will identify modified chemical compounds that induce biofilm dispersion. This research will in-crease our knowledge of P. aeruginosa biofilm dispersion, and allow us to explore new forms of treatment and therapy for CF patients with chronic in-fections that could be life threatening.
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    Pseudomonas Aeruginosa Biofilm Formation in Different Environments
    (Office of the Vice Chancellor for Research, 2013-04-05) Shadmand, Mehdi; Anderson, Gregory G.
    Various bacteria, such as the soil microbe Pseudomonas aeruginosa, form into strong structures to defend themselves from antibiotics and other harmful materials. These structures are called biofilms. The goal of this research is to isolate P. aeruginosa from several soil samples and determine whether they are able to form biofilms in those environments. Another goal of this research is to find out how different environmental factors affect the formation of Pseudomonas biofilms. We isolated P. aeruginosa from soil samples using Pseudomonas Isolation Agar plates. The colonies most similar to P. aeruginosa were picked, cultured, and tested by PCR in order to confirm that the strains were actually P. aeruginosa. Using these methods, so far we have collected 12 P. aeruginosa strains and we are collecting more strains from different soil samples. In future studies, we will determine whether these strains form biofilms in soil. We will also demonstrate the effect of magnesium on P. aeruginosa on biofilm formation. These studies will begin to investigate how altering environmental conditions can influence persistence of this bacterial pathogen in the soil. These studies can have broad implications for transmission of the bacterium from the environment to humans during disease.
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    The Radiopacity and Antimicrobial Properties of Different Radiopaque Double Antibiotic Pastes Used in Regenerative Endodontics
    (Elsevier, 2018-09) Verma, Rohan; Fischer, Benjamin I.; Gregory, Richard L.; Yassen, Ghaeth H.; Biomedical Sciences and Comprehensive Care, School of Dentistry
    Introduction We evaluated the radiopacity and antibacterial properties of various concentrations of double antibiotic paste (DAP) containing barium sulfate (BaSO4) or zirconium oxide (ZrO2) radiopaque agents. Methods The radiopacity of 1, 10, and 25 mg/mL DAP containing 30% (w/v) BaSO4 or ZrO2, DAP-free radiopaque pastes, and commercially available radiopaque calcium hydroxide (Ca[OH]2) were evaluated according to ISO 6876/2001 with slight modifications (n = 6 per group). Dentin samples (n = 70) infected anaerobically for 3 weeks with bacterial biofilms obtained from a root canal of an immature tooth with pulpal necrosis were treated with similar experimental pastes or received no treatment (n = 7). After 1 week, the pastes were rinsed off, and biofilm disruption assays were conducted. To show the residual antibacterial effects, sterile dentin samples (n = 70) were pretreated for 1 week with the same pastes (n = 7). The pastes were rinsed off, and the samples were immersed in phosphate-buffered saline for 24 hours and infected anaerobically with the same bacterial biofilm mentioned earlier for 3 weeks before conducting biofilm disruption assays. Sterile dentin blocks were used in both antibacterial analyses as negative control groups (n = 7). Wilcoxon rank sum tests were used for statistical analyses. Results No tested concentrations of BaSO4 DAP or ZrO2 DAP showed significant differences from Ca(OH)2 in radiopacity. However, all tested concentrations of BaSO4 DAP, ZrO2 DAP, and Ca(OH)2 exhibited significant direct antibacterial effects. ZrO2 DAP at 1 mg/mL and Ca(OH)2 did not show significant residual antibacterial effects. Conclusions BaSO4 DAP at 1 mg/mL provided significantly superior residual antibacterial effects and comparable radiopacity with the commercially available Ca(OH)2.