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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

Serum Amyloid A during Pseudomonas Exposure.Balb/c mice were endotracheally instilled with saline or 106 cfu of each Pseudomonas strain. At various times following exposure, blood was collected by cardiac puncture. Blood was processed for SAA detection by ELISA. Data is expressed as the fold-change compared to control values ± relative error (n = 3). For Pa31480 treatment at 48 h, the SAA values for each mouse are indicated by T1, T2, and T3. The variation in these values explains the large relative error observed. 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.g005: Serum Amyloid A during Pseudomonas Exposure.Balb/c mice were endotracheally instilled with saline or 106 cfu of each Pseudomonas strain. At various times following exposure, blood was collected by cardiac puncture. Blood was processed for SAA detection by ELISA. Data is expressed as the fold-change compared to control values ± relative error (n = 3). For Pa31480 treatment at 48 h, the SAA values for each mouse are indicated by T1, T2, and T3. The variation in these values explains the large relative error observed. 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: Another measure of systemic response to Pseudomonas exposure was that of blood SAA (Fig 5). At 24 h post-exposure, several Pp strains induced elevated SAA levels. At this time-point, PAO1 induced the largest increase (30-fold). Pa31480 did not cause changes at 24 h, but induced a mean 24-fold increase at 48 h. This mean result had a high relative error due to high variation among replicates within the treatment group. By 96 h, only PAO1 exposures demonstrated sustained elevation of SAA (21-fold), and by one-week post-exposure, levels for all treatments had resumed to control values.


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)

Serum Amyloid A during Pseudomonas Exposure.Balb/c mice were endotracheally instilled with saline or 106 cfu of each Pseudomonas strain. At various times following exposure, blood was collected by cardiac puncture. Blood was processed for SAA detection by ELISA. Data is expressed as the fold-change compared to control values ± relative error (n = 3). For Pa31480 treatment at 48 h, the SAA values for each mouse are indicated by T1, T2, and T3. The variation in these values explains the large relative error observed. 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.g005: Serum Amyloid A during Pseudomonas Exposure.Balb/c mice were endotracheally instilled with saline or 106 cfu of each Pseudomonas strain. At various times following exposure, blood was collected by cardiac puncture. Blood was processed for SAA detection by ELISA. Data is expressed as the fold-change compared to control values ± relative error (n = 3). For Pa31480 treatment at 48 h, the SAA values for each mouse are indicated by T1, T2, and T3. The variation in these values explains the large relative error observed. 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: Another measure of systemic response to Pseudomonas exposure was that of blood SAA (Fig 5). At 24 h post-exposure, several Pp strains induced elevated SAA levels. At this time-point, PAO1 induced the largest increase (30-fold). Pa31480 did not cause changes at 24 h, but induced a mean 24-fold increase at 48 h. This mean result had a high relative error due to high variation among replicates within the treatment group. By 96 h, only PAO1 exposures demonstrated sustained elevation of SAA (21-fold), and by one-week post-exposure, levels for all treatments had resumed to control values.

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