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Virulence Attributes and Host Response Assays for Determining Pathogenic Potential of Pseudomonas Strains Used in Biotechnology.

Tayabali AF, Coleman G, Nguyen KC - PLoS ONE (2015)

Bottom Line: However, Pf and Pp strains were the most antibiotic resistant, with ciprofloxacin and colistin being the most effective of those tested.Serum amyloid A was elevated at ≥ 48 h post-exposure by only some Pa strains.No relationship was observed between strains and levels of peripheral leukocytes.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology Laboratory, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Environmental Health Centre, Health Canada, Ottawa, Ontario, Canada.

ABSTRACT
Pseudomonas species are opportunistically pathogenic to humans, yet closely related species are used in biotechnology applications. In order to screen for the pathogenic potential of strains considered for biotechnology applications, several Pseudomonas strains (P.aeruginosa (Pa), P.fluorescens (Pf), P.putida (Pp), P.stutzeri (Ps)) were compared using functional virulence and toxicity assays. Most Pa strains and Ps grew at temperatures between 28°C and 42°C. However, Pf and Pp strains were the most antibiotic resistant, with ciprofloxacin and colistin being the most effective of those tested. No strain was haemolytic on sheep blood agar. Almost all Pa, but not other test strains, produced a pyocyanin-like chromophore, and caused cytotoxicity towards cultured human HT29 cells. Murine endotracheal exposures indicated that the laboratory reference strain, PAO1, was most persistent in the lungs. Only Pa strains induced pro-inflammatory and inflammatory responses, as measured by elevated cytokines and pulmonary Gr-1 -positive cells. Serum amyloid A was elevated at ≥ 48 h post-exposure by only some Pa strains. No relationship was observed between strains and levels of peripheral leukocytes. The species designation or isolation source may not accurately reflect pathogenic potential, since the clinical strain Pa10752 was relatively nonvirulent, but the industrial strain Pa31480 showed comparable virulence to PAO1. Functional assays involving microbial growth, cytotoxicity and murine immunological responses may be most useful for identifying problematic Pseudomonas strains being considered for biotechnology applications.

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Related in: MedlinePlus

Pulmonary Cytokine Levels During Pseudomonas Exposure.Balb/c mice were endotracheally instilled with saline or 106 cfu of each Pseudomonas strain. At various times following exposure, animals were euthanized and lungs were harvested. Following tissue homogenization, cytokine levels were measured using a multiplex bead array system. Data points represent the mean of three or four treated mice. Asterisks indicate statistically different values compared to saline exposures, as determined using ANOVA and Dunnett’s Multiple Comparison Test (p < 0.05). Bacteria with significant differences are indicated with red boxes in the graph legends.
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pone.0143604.g003: Pulmonary Cytokine Levels During Pseudomonas Exposure.Balb/c mice were endotracheally instilled with saline or 106 cfu of each Pseudomonas strain. At various times following exposure, animals were euthanized and lungs were harvested. Following tissue homogenization, cytokine levels were measured using a multiplex bead array system. Data points represent the mean of three or four treated mice. Asterisks indicate statistically different values compared to saline exposures, as determined using ANOVA and Dunnett’s Multiple Comparison Test (p < 0.05). Bacteria with significant differences are indicated with red boxes in the graph legends.

Mentions: Portions of lung were homogenized and analysed for levels of the pro-inflammatory cytokines, interleulin (IL) -1β, IL-6 and tumour necrosis factor (TNF)-α. Fig 3 demonstrates that some, but not all Pa strains were able to elevate cytokine levels. PAO1 and Pa31480 induced the greatest increase in all pro-inflammatory cytokines examined (up to 163-fold for PAO1-stimulated IL-1β). Pa700370 caused elevated levels of IL-1β and IL-6, as well as a statistically non-significant increase in TNF-α (14-fold). Pa10752 and Pa700371 did not cause any significant elevations in pro-inflammatory cytokines. Other than Pp700369, which resulted in a 25-fold mean increase in IL-6 relative to control, no other Pseudomonas strain caused significant elevations in any pro-inflammatory marker observed. For all strains, cytokine levels resumed to background control values at one week post-exposure.


Virulence Attributes and Host Response Assays for Determining Pathogenic Potential of Pseudomonas Strains Used in Biotechnology.

Tayabali AF, Coleman G, Nguyen KC - PLoS ONE (2015)

Pulmonary Cytokine Levels During Pseudomonas Exposure.Balb/c mice were endotracheally instilled with saline or 106 cfu of each Pseudomonas strain. At various times following exposure, animals were euthanized and lungs were harvested. Following tissue homogenization, cytokine levels were measured using a multiplex bead array system. Data points represent the mean of three or four treated mice. Asterisks indicate statistically different values compared to saline exposures, as determined using ANOVA and Dunnett’s Multiple Comparison Test (p < 0.05). Bacteria with significant differences are indicated with red boxes in the graph legends.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664251&req=5

pone.0143604.g003: Pulmonary Cytokine Levels During Pseudomonas Exposure.Balb/c mice were endotracheally instilled with saline or 106 cfu of each Pseudomonas strain. At various times following exposure, animals were euthanized and lungs were harvested. Following tissue homogenization, cytokine levels were measured using a multiplex bead array system. Data points represent the mean of three or four treated mice. Asterisks indicate statistically different values compared to saline exposures, as determined using ANOVA and Dunnett’s Multiple Comparison Test (p < 0.05). Bacteria with significant differences are indicated with red boxes in the graph legends.
Mentions: Portions of lung were homogenized and analysed for levels of the pro-inflammatory cytokines, interleulin (IL) -1β, IL-6 and tumour necrosis factor (TNF)-α. Fig 3 demonstrates that some, but not all Pa strains were able to elevate cytokine levels. PAO1 and Pa31480 induced the greatest increase in all pro-inflammatory cytokines examined (up to 163-fold for PAO1-stimulated IL-1β). Pa700370 caused elevated levels of IL-1β and IL-6, as well as a statistically non-significant increase in TNF-α (14-fold). Pa10752 and Pa700371 did not cause any significant elevations in pro-inflammatory cytokines. Other than Pp700369, which resulted in a 25-fold mean increase in IL-6 relative to control, no other Pseudomonas strain caused significant elevations in any pro-inflammatory marker observed. For all strains, cytokine levels resumed to background control values at one week post-exposure.

Bottom Line: However, Pf and Pp strains were the most antibiotic resistant, with ciprofloxacin and colistin being the most effective of those tested.Serum amyloid A was elevated at ≥ 48 h post-exposure by only some Pa strains.No relationship was observed between strains and levels of peripheral leukocytes.

View Article: PubMed Central - PubMed

Affiliation: Biotechnology Laboratory, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Environmental Health Centre, Health Canada, Ottawa, Ontario, Canada.

ABSTRACT
Pseudomonas species are opportunistically pathogenic to humans, yet closely related species are used in biotechnology applications. In order to screen for the pathogenic potential of strains considered for biotechnology applications, several Pseudomonas strains (P.aeruginosa (Pa), P.fluorescens (Pf), P.putida (Pp), P.stutzeri (Ps)) were compared using functional virulence and toxicity assays. Most Pa strains and Ps grew at temperatures between 28°C and 42°C. However, Pf and Pp strains were the most antibiotic resistant, with ciprofloxacin and colistin being the most effective of those tested. No strain was haemolytic on sheep blood agar. Almost all Pa, but not other test strains, produced a pyocyanin-like chromophore, and caused cytotoxicity towards cultured human HT29 cells. Murine endotracheal exposures indicated that the laboratory reference strain, PAO1, was most persistent in the lungs. Only Pa strains induced pro-inflammatory and inflammatory responses, as measured by elevated cytokines and pulmonary Gr-1 -positive cells. Serum amyloid A was elevated at ≥ 48 h post-exposure by only some Pa strains. No relationship was observed between strains and levels of peripheral leukocytes. The species designation or isolation source may not accurately reflect pathogenic potential, since the clinical strain Pa10752 was relatively nonvirulent, but the industrial strain Pa31480 showed comparable virulence to PAO1. Functional assays involving microbial growth, cytotoxicity and murine immunological responses may be most useful for identifying problematic Pseudomonas strains being considered for biotechnology applications.

Show MeSH
Related in: MedlinePlus