Phages of Pseudomonas aeruginosa: response to environmental factors and in vitro ability to inhibit bacterial growth and biofilm formation

Knežević, Petar; Obreht, Dragana; Curcin, Sanja; Petrušić, Milivoje; Aleksić, Verica; Kostanjšek, Rok; Petrovic, O.

doi:10.1111/j.1365-2672.2011.05043.x

Cited by 54 publications

(37 citation statements)

References 37 publications

(57 reference statements)

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“…It is well known that phage are sensitive to physical and chemical stresses including shear [71], [72], temperature [72], pH [73], ionic strength [74], exposure to organic solvents [35], [36] etc. Formulations used for phage encapsulation require careful selection of constituents and encapsulation conditions.…”

Section: Discussionmentioning

confidence: 99%

Microencapsulation of Clostridium difficile specific bacteriophages using microfluidic glass capillary devices for colon delivery using pH triggered release

et al. 2017

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The prevalence of pathogenic bacteria acquiring multidrug antibiotic resistance is a global health threat to mankind. This has motivated a renewed interest in developing alternatives to conventional antibiotics including bacteriophages (viruses) as therapeutic agents. The bacterium Clostridium difficile causes colon infection and is particularly difficult to treat with existing antibiotics; phage therapy may offer a viable alternative. The punitive environment within the gastrointestinal tract can inactivate orally delivered phages. C. difficile specific bacteriophage, myovirus CDKM9 was encapsulated in a pH responsive polymer (Eudragit® S100 with and without alginate) using a flow focussing glass microcapillary device. Highly monodispersed core-shell microparticles containing phages trapped within the particle core were produced by in situ polymer curing using 4-aminobenzoic acid dissolved in the oil phase. The size of the generated microparticles could be precisely controlled in the range 80 μm to 160 μm through design of the microfluidic device geometry and by varying flow rates of the dispersed and continuous phase. In contrast to free ‘naked’ phages, those encapsulated within the microparticles could withstand a 3 h exposure to simulated gastric fluid at pH 2 and then underwent a subsequent pH triggered burst release at pH 7. The significance of our research is in demonstrating that C. difficile specific phage can be formulated and encapsulated in highly uniform pH responsive microparticles using a microfluidic system. The microparticles were shown to afford significant protection to the encapsulated phage upon prolonged exposure to an acid solution mimicking the human stomach environment. Phage encapsulation and subsequent release kinetics revealed that the microparticles prepared using Eudragit® S100 formulations possess pH responsive characteristics with phage release triggered in an intestinal pH range suitable for therapeutic purposes. The results reported here provide proof-of-concept data supporting the suitability of our approach for colon targeted delivery of phages for therapeutic purposes.

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Section: Discussionmentioning

confidence: 99%

Microencapsulation of Clostridium difficile specific bacteriophages using microfluidic glass capillary devices for colon delivery using pH triggered release

et al. 2017

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“…The method for measuring a biofilm on a plastic surface has been described previously (25,26). Briefly, bacteria were inoculated into 1 ml LB broth contained in a well of a polystyrene 96-well plate at a concentration of 1 ϫ 10 6 CFU/ml.…”

Section: Purification Of Caementioning

confidence: 99%

Phage-Encoded Colanic Acid-Degrading Enzyme Permits Lytic Phage Infection of a Capsule-Forming Resistant Mutant Escherichia coli Strain

Kim

Hong

et al. 2015

Appl Environ Microbiol

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In this study, we isolated a bacteriophage T7-resistant mutant strain of Escherichia coli (named S3) and then proceeded to characterize it. The mutant bacterial colonies appeared to be mucoid. Microarray analysis revealed that genes related to colanic acid production were upregulated in the mutant. Increases in colanic acid production by the mutant bacteria were observed when L-fucose was measured biochemically, and protective capsule formation was observed under an electron microscope. We found a point mutation in the lon gene promoter in S3, the mutant bacterium. Overproduction of colanic acid was observed in some phage-resistant mutant bacteria after infection with other bacteriophages, T4 and lambda. Colanic acid overproduction was also observed in clinical isolates of E. coli upon phage infection. The overproduction of colanic acid resulted in the inhibition of bacteriophage adsorption to the host. Biofilm formation initially decreased shortly after infection but eventually increased after 48 h of incubation due to the emergence of the mutant bacteria. Bacteriophage PBECO4 was shown to infect the colanic acid-overproducing mutant strains of E. coli. We confirmed that the gene product of open reading frame 547 (ORF547) of PBECO4 harbored colanic acid-degrading enzymatic (CAE) activity. Treatment of the T7-resistant bacteria with both T7 and PBECO4 or its purified enzyme (CAE) led to successful T7 infection. Biofilm formation decreased with the mixed infection, too. This procedure, using a phage cocktail different from those exploiting solely receptor differences, represents a novel strategy for overcoming phage resistance in mutant bacteria. With the appearance of antibiotic-resistant pathogenic bacteria, bacteriophage therapy is considered a likely alternative to antibiotics (1-4). The advantages of phage therapy include autodosing (7), minimal influence on normal flora, the ability to control biofilms, and low inherent toxicity (5-8). Although many successful cases of control of bacterial infections with phages have been reported (9), one problem associated with phage therapy is the emergence of phage-resistant mutant bacteria. Two representative mechanisms of bacteria for resisting infection by phage are the prevention of phage adsorption and the cutting of the invading phage genome (10). The former may involve the masking of the phage receptor, the production of a competitive inhibitor, or the production of an extracellular matrix (7, 11). The latter may involve restriction modification or the CRISPR (clustered regularly interspaced short palindromic repeat)-Cas (CRISPR-associated) system (10, 12, 13). Accordingly, current phage therapy generally adopts a cocktail strategy in which phages targeting different cellular receptors are mixed (6).One of the extracellular matrices produced by bacteria for resisting phage adsorption is colanic acid. Colanic acid is an exopolysaccharide (EPS) that protects bacteria of the family Enterobacteriaceae and acts by forming a protective capsule. It is produced upon osmo...

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“…The enhanced susceptibility of preattached cells to the bacteriophage was mainly attributed to the availability of specific binding sites (33). The number of preattached Salmonella Typhimurium P22+ cells was reduced by 0.87 log CFU/cm2 in the absence of bacteriophage P22 compared with the initial number of preattached cells (5.28 log CFU/ cm2), which implies that the cryptic prophages were spontaneously released from the Salmonella Typhimurium P22+ cells under stress conditions, such as nutrient depletion and high cell density, known as spontaneous phage induction (5,11,19,27,31,35). The number of preattached Salmonella Typhimurium P22+ cells was increased up to 6.1 log CFU/cm2 in the presence of bacteriophage P22.…”

Section: S T Yp H Im U Riu M P 2 2 *mentioning

confidence: 99%

In Vitro Assessment of the Susceptibility of Planktonic and Attached Cells of Foodborne Pathogens to Bacteriophage P22-Mediated Salmonella Lysates

Ahn

Kim

Jung

et al. 2013

Journal of Food Protection

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This study was designed to evaluate the lytic activity of bacteriophage P22 against Salmonella Typhimurium ATCC 19585 (Salmonella Typhimurium P22(-)) at various multiplicities of infections (MOIs), the susceptibility of preattached Salmonella cells against bacteriophage P22, and the effect of P22-mediated bacterial lysates (extracellular DNA) on the attachment ability of Listeria monocytogenes ATCC 7644 and enterohemorrhagic Escherichia coli ATCC 700927 to surfaces. The numbers of attached Salmonella Typhimurium P22(-) cells were effectively reduced to below the detection limit (1 log CFU/ml) at the fixed inoculum levels of 3 × 10(-) CFU/ml (MOI = 3.12) and 3 × 10(3) CFU/ml (MOI = 4.12) by bacteriophage P22. The attached Salmonella Typhimurium P22(-) cells remained more than 2 log CFU/ml, with increasing inoculum levels from 3 × 10(4) to 3 × 10(7) CFU/ml infected with 4 × 10(8) PFU/ml of P22. The number of preattached Salmonella Typhimurium P22(-) cells was noticeably reduced by 2.72 log in the presence of P22. The highest specific attachment ability values for Salmonella Typhimurium P22(-), Salmonella Typhimurium ATCC 23555 carrying P22 prophage (Salmonella Typhimurium P22(+)), L. monocytogenes, and enterohemorrhagic E. coli were 2.09, 1.06, 1.86, and 1.08, respectively, in the bacteriophage-mediated cell-free supernatants (CFS) containing high amounts of extracellular DNA. These results suggest that bacteriophages could potentially be used to effectively eliminate planktonic and preattached Salmonella Typhimurium P22(-) cells with increasing MOI. However, further research is needed to understand the role of bacteriophage-induced lysates in bacterial attachment, which can provide useful information for the therapeutic use of bacteriophage in the food system.

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Phages of Pseudomonas aeruginosa: response to environmental factors and in vitro ability to inhibit bacterial growth and biofilm formation

Cited by 54 publications

References 37 publications

Microencapsulation of Clostridium difficile specific bacteriophages using microfluidic glass capillary devices for colon delivery using pH triggered release

Microencapsulation of Clostridium difficile specific bacteriophages using microfluidic glass capillary devices for colon delivery using pH triggered release

Phage-Encoded Colanic Acid-Degrading Enzyme Permits Lytic Phage Infection of a Capsule-Forming Resistant Mutant Escherichia coli Strain

In Vitro Assessment of the Susceptibility of Planktonic and Attached Cells of Foodborne Pathogens to Bacteriophage P22-Mediated Salmonella Lysates

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