Journal: Microorganisms

Article Title: Geno- and Phenotypic Characteristics of a Klebsiella pneumoniae ST20 Isolate with Unusual Colony Morphology

doi: 10.3390/microorganisms10102063

Figure Lengend Snippet: Representative images of phenotypic assays and phenotypic assays related to biofilm forming abilities and pathogenesis. ( a ) Production of exopolysaccharides. Isolates were plated on BHI agar and incubated for 24 h at 37 °C. PBIO1953 was tested negative for the production of exopolysaccharides, hvKP1 was tested positive and the result for PBIO3459 could not be determined clearly. The negative control (NC) was tested negative and the positive control (PC) positive. ( b ) Cellulose and curli fimbriae production was investigated in long-term colonies. PBIO1953 and hvKP1 produced neither structures while the phenotype of PBIO3459 differed from usual (control) long-term colonies. The PC produced both curli fimbriae and cellulose. ( c ) Adherence ability given as specific biofilm factor. Results are given as mean values with standard deviation. ( d ) Cellulose production of the respective isolates. Results are expressed as mean fluorescence intensities with standard deviation ( n = 3). Statistical significance was tested with one-way ANOVA (with Dunnett’s multiple comparison post hoc test); **** p < 0.0001.

Article Snippet: The ability to produce exopolysaccharides was tested using BHI agar plates supplemented with 5% ( w / v ) sucrose (Carl Roth, Karlsruhe, Germany) and 0.08% ( w / v ) congo red (Carl Roth, Karlsruhe, Germany) as previously described [ ].

Techniques: Incubation, Negative Control, Positive Control, Produced, Control, Standard Deviation, Fluorescence, Comparison

Journal: Microbiology Spectrum

Article Title: Listeria monocytogenes Sublethal Injury and Viable-but-Nonculturable State Induced by Acidic Conditions and Disinfectants

doi: 10.1128/Spectrum.01377-21

Figure Lengend Snippet: Populations (log CFU/ml) of L. monocytogenes , strain Scott A, after incubation for 0, 1, 2, 3, 4, or 5 h under the following conditions: (A) AA, pH 3.0, at 20°C, (B) AA, pH 2.7, at 20°C, (C) AA, pH 2.5, at 20°C, (D) AA, pH 3.0, at 4°C, (E) AA, pH 2.7, at 4°C, (F) AA, pH 2.5, at 4°C, (G) HCl, pH 3.0, at 20°C, (H) HCl, pH 2.7, at 20°C, (I) HCl, pH 2.5, at 20°C, (J) HCl, pH 3.0, at 4°C, (K) HCl, pH 2.7, at 4°C, and (L) HCl, pH 2.5, at 4°C. Total culturable (dark gray bars) and noninjured (light gray bars) population levels were measured after incubation for 2 days and 5 days at 37°C on TSAYE supplemented with 0% and 5% NaCl, respectively. Bars represent mean values ± standard deviations (SD) from 3 independent biological replicates. Statistically significant differences ( P < 0.05) are indicated with different uppercase (TSAYE) and lowercase (TSAYE+5%NaCl) letters, respectively. The dotted line represents the limit of detection (LOD). **, P < 0.05; ***, P < 0.01; n.s., not significant.

Article Snippet: To differentiate the injured subpopulation from the total culturable population, growth in TSAYE supplemented with 5% NaCl (wt/vol) (AppliChem) was compared to growth in TSAYE with 0.5% NaCl.

Techniques: Incubation

Journal: Microbiology Spectrum

Article Title: Listeria monocytogenes Sublethal Injury and Viable-but-Nonculturable State Induced by Acidic Conditions and Disinfectants

doi: 10.1128/Spectrum.01377-21

Figure Lengend Snippet: Populations (log CFU/ml) of L. monocytogenes , strain Scott A, after incubation for 0, 30, 60, 300, 900, or 1,800 s under the following conditions: (A) PAA, 0.5 ppm, at 20°C, (B) PAA, 5 ppm, at 20°C, (C) PAA, 10 ppm, at 20°C, (D) PAA, 0.5 ppm, at 4°C, (E) PAA, 5 ppm, at 4°C, (F) PAA, 10 ppm, at 4°C, (G) SH, 0.5 ppm, at 20°C, (H) SH, 5 ppm, at 20°C, (I) SH, 10 ppm, at 20°C, (J) SH, 0.5 ppm, at 4°C, (K) SH, 5 ppm, at 4°C, and (L) SH, 10 ppm, at 4°C. Total culturable (dark gray bars) and noninjured (light gray bars) population levels were measured after incubation for 2 days and 5 days at 37°C on TSAYE supplemented with 0% and 5% NaCl, respectively. Bars represent mean values ± SD from 3 independent biological replicates. Statistically significant differences ( P < 0.05) are indicated with different uppercase (TSAYE) and lowercase (TSAYE+5%NaCl) letters, respectively. The dotted line represents the limit of detection (LOD). *, P < 0.1; **, P < 0.05; ***, P < 0.01; n.s., not significant.

Article Snippet: To differentiate the injured subpopulation from the total culturable population, growth in TSAYE supplemented with 5% NaCl (wt/vol) (AppliChem) was compared to growth in TSAYE with 0.5% NaCl.

Techniques: Incubation

Journal: Microbiology Spectrum

Article Title: Listeria monocytogenes Sublethal Injury and Viable-but-Nonculturable State Induced by Acidic Conditions and Disinfectants

doi: 10.1128/Spectrum.01377-21

Figure Lengend Snippet: Populations (log CFU/ml) of L. monocytogenes , strain Scott A, after incubation for 0, 30, 60, 300, 900, or 1,800 s under the following conditions: (A) PAA, 20 ppm, at 20°C, (B) PAA, 30 ppm, at 20°C, (C) PAA, 40 ppm, at 20°C, (D) PAA, 20 ppm, at 4°C, (E) PAA, 30 ppm, at 4°C, and (F) PAA, 40 ppm, at 4°C. Total culturable (dark gray bars) and noninjured (light gray bars) population levels were measured after incubation for 2 days and 5 days at 37°C on TSAYE supplemented with 0% and 5% NaCl, respectively. Bars represent mean values ± SD from 3 independent biological replicates. Statistically significant differences ( P < 0.05) are indicated with different uppercase (TSAYE) and lowercase (TSAYE+5%NaCl) letters, respectively. The dotted line represents the limit of detection (LOD). *, P < 0.1; **, P < 0.05; n.s., not significant.

Article Snippet: To differentiate the injured subpopulation from the total culturable population, growth in TSAYE supplemented with 5% NaCl (wt/vol) (AppliChem) was compared to growth in TSAYE with 0.5% NaCl.

Techniques: Incubation

Journal: Microbiology Spectrum

Article Title: Listeria monocytogenes Sublethal Injury and Viable-but-Nonculturable State Induced by Acidic Conditions and Disinfectants

doi: 10.1128/Spectrum.01377-21

Figure Lengend Snippet: Populations (log CFU/ml) of L. monocytogenes , strain Scott A, after incubation for 0, 1, 2, or 3 h at 20°C in Ringer’s solution with 20 ppm (A), 30 ppm (C), or 40 ppm (E) PAA. Total culturable (dark gray bars) and noninjured (light gray bars) population levels were measured after incubation for 2 and 5 days at 37°C on TSAYE supplemented with 0% and 5% NaCl, respectively. Bars represent mean values ± SD from one experiment with six independent samples ( n = 6). Statistically significant differences ( P < 0.05) are indicated with different uppercase and lowercase letters for TSAYE and TSAYE+5%NaCl, respectively. The dotted line represents the limit of detection (LOD). ***, P < 0.01; n.s., not significant. Each time point relates to several images acquired at different fields of view (FOV) of the same sample. Enumeration results (%) for cells exhibiting fluorescence (CFDA + /PI − , green; CFDA − /PI + , red; CFDA + /PI + , orange; or CFDA − /PI − , black), considering several images of different fields of view (FOV) at each time point after treatment with PAA at 20 ppm (0 h, 5 FOV; 1 h, 4 FOV; 2 h, 5 FOV; 3 h, 5 FOV) (B), 30 ppm (0 h, 4 FOV; 1 h, 5 FOV; 2 h, 5 FOV; 3 h, 5 FOV) (D), and 40 ppm (0 h, 4 FOV; 1 h, 5 FOV; 2 h, 5 FOV; 3 h, 5 FOV) (F).

Article Snippet: To differentiate the injured subpopulation from the total culturable population, growth in TSAYE supplemented with 5% NaCl (wt/vol) (AppliChem) was compared to growth in TSAYE with 0.5% NaCl.

Techniques: Incubation, Fluorescence