Pseudomonas aeruginosa Biofilm Formation and Its Control (original) (raw)
Related papers
In vitro pseudomonas aeruginosa biofilms
Pseudomonas aeruginosa bacterial biofilms are the leading cause of mortality among cystic fibrosis (CF) patients. Biofilms contain bacteria attached to a surface and encased in a protective matrix. Since bacteria within a biofilm are less susceptible to antibiotics, a new approach is to use dispersion compounds that cause the biofilms to release free-swimming bacteria. Our approach has focused on combining nutrient dispersion compounds with antibiotics to increase eradication of bacteria within biofilms. This approach takes advantage of the enhanced susceptibility of free-swimming bacteria to antibiotics, compared to bacteria within biofilms. Ultimately, this research will guide the development of an aerosol therapy containing both antibiotic and dispersion compounds to treat bacterial biofilm infections. To study the effect of antibiotic and dispersion compound treatments on biofilm eradication, a high-throughput screening assay was used to assess the effect on young Pseudomonas aeruginosa biofilms. In addition, a Lab-Tek chambered coverglass system imaged via confocal microscopy was used to assess the effect on mature Pseudomonas aeruginosa biofilms. Seven antibiotics (amikacin disulfate, tobramycin sulfate, colistin sulfate, colistin methanesulfonate (CMS), polymyxinB sulfate, erythromycin, and ciprofloxacin hydrochloride) were tested alone or in combination with four nutrient dispersion compounds (sodium citrate, succinic acid, xylitol, and glutamic acid) to assess the level of eradication of bacteria within biofilms. For young biofilms, 15 of 24 combinations significantly eliminated more live bacteria within the biofilms (measured in colony forming units per milliliter) compared to antibiotics alone. In the more mature biofilm system, only 3 out of 26 combinations resulted in a higher percentage of live biofilm bacteria being eliminated compared to antibiotics alone, showing the importance of biofilm age in the effectiveness of these potential combination therapies. To aid in confocal microscopic analysis of biofilms, an automated quantification program called STAINIFICATION was developed. This new program can be used to iii ACKNOWLEDGMENTS I would like to thank my advisor Dr. Jennifer Fiegel for her guidance and support.
In Vivo Efficacy of Antimicrobials against Biofilm-Producing Pseudomonas aeruginosa
Antimicrobial Agents and Chemotherapy, 2015
Patients suffering from cystic fibrosis (CF) are commonly affected by chronic Pseudomonas aeruginosa biofilm infections. This is the main cause for the high disease severity. In this study, we demonstrate that P. aeruginosa is able to efficiently colonize murine solid tumors after intravenous injection and to form biofilms in this tissue. Biofilm formation was evident by electron microscopy. Such structures could not be observed with transposon mutants, which were defective in biofilm formation. Comparative transcriptional profiling of P. aeruginosa indicated physiological similarity of the bacteria in the murine tumor model and the CF lung. The efficacy of currently available antibiotics for treatment of P. aeruginosa -infected CF lungs, such as ciprofloxacin, colistin, and tobramycin, could be tested in the tumor model. We found that clinically recommended doses of these antibiotics were unable to eliminate wild-type P. aeruginosa PA14 while being effective against biofilm-defecti...
Clinical Impact of Antibiotics for the Treatment of Pseudomonas aeruginosa Biofilm Infections
Frontiers in Microbiology
Bacterial biofilms are highly recalcitrant to antibiotic therapies due to multiple tolerance mechanisms. The involvement of Pseudomonas aeruginosa in a wide range of biofilmrelated infections often leads to treatment failures. Indeed, few current antimicrobial molecules are still effective on tolerant sessile cells. In contrast, studies increasingly showed that conventional antibiotics can, at low concentrations, induce a phenotype change in bacteria and consequently, the biofilm formation. Understanding the clinical effects of antimicrobials on biofilm establishment is essential to avoid the use of inappropriate treatments in the case of biofilm infections. This article reviews the current knowledge about bacterial growth within a biofilm and the preventive or inducer impact of standard antimicrobials on its formation by P. aeruginosa. The effect of antibiotics used to treat biofilms of other bacterial species, as Staphylococcus aureus or Escherichia coli, was also briefly mentioned. Finally, it describes two in vitro devices which could potentially be used as antibiotic susceptibility testing for adherent bacteria.
Journal of Clinical Microbiology, 2002
Evidence suggests that Pseudomonas aeruginosa bacteria form biofilms within the airways of adults with cystic fibrosis (CF). The objective of this study was to determine whether clinical isolates of P. aeruginosa recovered from adults with CF have similar susceptibilities to individual antibiotics and to antibiotic combinations when grown as adherent monolayers or as biofilms compared to when they are grown using planktonic methods. Twelve multiresistant P. aeruginosa isolates, one mucoid and one nonmucoid from each of six CF patients, were grown conventionally under planktonic conditions, as adherent bacterial monolayers, and as biofilms. Each bacterial isolate remained genotypically identical despite being cultured under planktonic, adherent, or biofilm growth conditions. Isolates grown as adherent monolayers and as biofilms were less susceptible to bactericidal killing by individual antibiotics compared to those grown planktonically. More importantly, biofilm-grown bacteria, but not adherent monolayer-grown bacteria, were significantly less susceptible to two-and three-drug combinations of antibiotics than were planktonically grown bacteria (P ؍ 0.005). We conclude that biofilm-grown bacteria derived from patients with CF show decreased susceptibility to the bactericidal effects of antibiotic combinations than do adherent and planktonically grown bacteria.
Advances in Microbiology, 2020
Biofilms are dense bacterial colonies, derived from microbially derived sessile community, networked within a polysaccharide matrix with a distinct architecture that has the attachment potential to both alive and abiotic surfaces. Pseudomonas aeruginosa is a model biofilm forming microorganism associated with remarkable morbidity and mortality rate due to emergence of antibiotic resistant pathogenic bacteria. Moreover, Pseudomonas aeruginosa originating from a biofilm is more resistant to a wide range of antibiotics than the planktonic bacteria. This research was planned to develop a comparative study of the biofilm production between potential, antimicrobial resistance of Pseudomonas aeruginosa isolated from mature environmental biofilm and clinical strain of the same species that did not derive from biofilm. It was observed that the Pseudomonas aeruginosa from environmental isolates were resistant to 15 prominent antibiotics, while clinical strain was comparatively resistant to only few of them. A confirmatory analysis of biofilm formation and antibiotic resistance pattern of these two groups of organisms was checked by 96-well microtiter plate and the disc diffusion method respectively. Finally, the results portrayed that the environmental strains with high drug resistance, potentially formed a considerable amount of biofilm in the period of a week whereas; clinical stains formed a negligible amount of biofilm within the same time frame.
The Brazilian Journal of Infectious Diseases, 2011
Biofilm production is an important mechanism for bacterial survival and its occurrence together with antimicrobial resistance represents a challenge for clinical management. Here, we evaluated the ability for biofilm production among P. aeruginosa isolates from patients with or without cystic fibrosis (CF) using two distinct media, besides determining the antimicrobial susceptibility profile of these isolates for eight antimicrobial agents. The ability for biofilm production when TSB medium was used was higher than when used CF sputum media (p = 0.0198). However, P. aeruginosa isolates from CF have demonstrated similar performance for biofilm production, independently of the medium used. Besides, among the biofilm-producing isolates, those recovered from CF were more resistant to the carbapenems (meropenem and imipenem) agents than those isolates from non-CF isolates.
Antibiotics, 2020
The ability of Pseudomonas aeruginosa to form biofilm during a long-term infection makes it difficult to treat patients correctly. The current clinical antimicrobial susceptibility testing methods are based on the study of planktonic strains. A standardized protocol to analyze the antimicrobial susceptibility in biofilms is necessary for routine laboratories. The aims of this study were to develop a simple biofilm model and to study the antimicrobial susceptibility of P. aeruginosa strains in biofilm growth. Different artificial sputum media, and aerobiosis and microaerobiosis conditions were analyzed using a microtiter plate method and P. aeruginosa PAO1 as reference strain. Planktonic and biofilm antimicrobial susceptibility to cefepime, imipenem, azithromycin, gentamicin, tobramycin, and ciprofloxacin were determined in clinical and non-clinical P. aeruginosa strains. The Synthetic Cystic Fibrosis Medium was proposed as a good medium. The biofilm greatly increased the resistance ...
Pseudomonas aeruginosa and the in vitroand in vivo biofilm mode of growth
Microbes and Infection, 2001
The biofilm mode of growth is the survival strategy of enviromental bacteria like Pseudomonas aeruginosa. Such P. aeruginosa biofilms also occur in the lungs of chronically infected cystic fibrosis patients, where they protect the bacteria against antibiotics and the immune response. The lung tissue damage is due to immune complex mediated chronic inflammation dominated by polymorphonuclear leukocytes releasing proteases and oxygen radicals.
Combating Pseudomonas aeruginosa Biofilms by Potential Biofilm
Ten potential antibiofilm agents (N-acetylcysteine (NAC), ambroxol, piroxicam, diclofenac sodium, ketoprofen, 4nitropyrdidine-N-oxide (4NPO), sodium ascorbate, sucralose, xylitol and sorbitol) showed varied activity against preformed biofilms formed by twenty clinical isolates of Pseudomonas aeruginosa as demonstrated by minimum biofilm inhibitory concentration (MBIC). 4NPO was the most active; Diclofenac sodium, ketoprofen, N-acetylcysteine, ambroxol, sodium ascorbate and piroxicam showed moderate activity, while sucralose, xylitol, and sorbitol demonstrated weak activity.
International Journal of Molecular Sciences, 2021
The occurrence of Pseudomonas aeruginosa (PA) persisters, including viable but non-culturable (VBNC) forms, subpopulations of tolerant cells that can survive high antibiotic doses, is the main reason for PA lung infections failed eradication and recurrence in Cystic Fibrosis (CF) patients, subjected to life-long, cyclic antibiotic treatments. In this paper, we investigated the role of subinhibitory concentrations of different anti-pseudomonas antibiotics in the maintenance of persistent (including VBNC) PA cells in in vitro biofilms. Persisters were firstly selected by exposure to high doses of antibiotics and their abundance over time evaluated, using a combination of cultural, qPCR and flow cytometry assays. Two engineered GFP-producing PA strains were used. The obtained results demonstrated a major involvement of tobramycin and bacterial cell wall-targeting antibiotics in the resilience to starvation of VBNC forms, while the presence of ciprofloxacin and ceftazidime/avibactam lea...