Journal: Frontiers in Immunology

Article Title: A Strong Synergy Between the Thiopeptide Bacteriocin Micrococcin P1 and Rifampicin Against MRSA in a Murine Skin Infection Model

doi: 10.3389/fimmu.2021.676534

Figure Lengend Snippet: Synergy assessment between MP1 and a panel of antibiotics against MRSA Xen31.

Article Snippet: For topical use in mice the final mixture in APO Base 30 cream contained 10 μg/ml MP1 and 150 μg/ml rifampicin which were about 100 times higher than their MIC values recorded in the checkerboard assay, since MRSA Xen31 parental strain S. aureus ATCC 33591 is known to produce biofilms on surfaces within 24h ( ) and staphylococcal biofilms are 10- to 1000-fold more resistant to antimicrobials compared to planktonic cells ( ).

Techniques:

Journal: Frontiers in Immunology

Article Title: A Strong Synergy Between the Thiopeptide Bacteriocin Micrococcin P1 and Rifampicin Against MRSA in a Murine Skin Infection Model

doi: 10.3389/fimmu.2021.676534

Figure Lengend Snippet: Assessment of the antimicrobial activity of MP1(10 µg/ml), rifampicin (150 µg/ml) and the combination (MP1, 10µg/ml + rifampicin, 150µg/ml) in APO base cream 30%. Cream with not addition was included as negative control. The activity was tested with softagar overlay assay using MRSA Xen31 as indicator strain.

Article Snippet: For topical use in mice the final mixture in APO Base 30 cream contained 10 μg/ml MP1 and 150 μg/ml rifampicin which were about 100 times higher than their MIC values recorded in the checkerboard assay, since MRSA Xen31 parental strain S. aureus ATCC 33591 is known to produce biofilms on surfaces within 24h ( ) and staphylococcal biofilms are 10- to 1000-fold more resistant to antimicrobials compared to planktonic cells ( ).

Techniques: Activity Assay, Cream, Negative Control, Overlay Assay

Journal: Frontiers in Immunology

Article Title: A Strong Synergy Between the Thiopeptide Bacteriocin Micrococcin P1 and Rifampicin Against MRSA in a Murine Skin Infection Model

doi: 10.3389/fimmu.2021.676534

Figure Lengend Snippet: Bioluminescence from mice skin infections during different treatments. Box plots of bioluminescent signals produced by MRSA Xen31 (in photons per second per square centimeter per steradian) in differently treated mouse groups. The days of treatment are indicated with arrows. (A) mice received daily treatments for nine days. (B) mice received daily treatments for four days before they were left untreated for the rest of the experiment. The area within each box represents the interquartile region (IQR), which comprises the second and third quartiles and describes the interval of values where the middle 50% of the observed data are distributed. The horizontal black line within each box represents the median value. The extent of the IQR (box height) express the degree of variability measured within the middle 50% of the observed data, with whiskers extending out at either side of the boxes marking the minimum and maximum observed values, as well as the variability outside the middle 50% of values (whisker length). Outliers are displayed as data that extend out of the whisker limit (1.5 times the IQR).

Article Snippet: For topical use in mice the final mixture in APO Base 30 cream contained 10 μg/ml MP1 and 150 μg/ml rifampicin which were about 100 times higher than their MIC values recorded in the checkerboard assay, since MRSA Xen31 parental strain S. aureus ATCC 33591 is known to produce biofilms on surfaces within 24h ( ) and staphylococcal biofilms are 10- to 1000-fold more resistant to antimicrobials compared to planktonic cells ( ).

Techniques: Produced, Whisker Assay

Journal: Frontiers in Immunology

Article Title: A Strong Synergy Between the Thiopeptide Bacteriocin Micrococcin P1 and Rifampicin Against MRSA in a Murine Skin Infection Model

doi: 10.3389/fimmu.2021.676534

Figure Lengend Snippet: (A) In vivo images of bioluminescent signals produced by MRSA Xen31(in photons/second/cm 2 /steradian) from the different mouse groups on the last day of the experiment; left column: with nine daily treatments; right column with four daily treatments. (B) Rifampicin and fucidin resistance develops during the treatment of mice. Rifampicin resistant cells (Rif-resistance) and fucidic acid resistant cells (Fucidic acid resistance) isolated from the wounds with strong bioluminescent signals were rechallenged and shown to be resistant to rifampicin (Rif) and fusidic acid (F.a.) but not to the MP1-rifampicin mixture. Wildtype MRSA Xen31 cells exposed to the MP1-ripamicin mixture, rifampicin and fusidic acid were sensitive to all three antimicrobials.

Article Snippet: For topical use in mice the final mixture in APO Base 30 cream contained 10 μg/ml MP1 and 150 μg/ml rifampicin which were about 100 times higher than their MIC values recorded in the checkerboard assay, since MRSA Xen31 parental strain S. aureus ATCC 33591 is known to produce biofilms on surfaces within 24h ( ) and staphylococcal biofilms are 10- to 1000-fold more resistant to antimicrobials compared to planktonic cells ( ).

Techniques: In Vivo, Produced, Isolation

Journal: bioRxiv

Article Title: An antibiotic-free antimicrobial combination of bacteriocins and a peptidoglycan hydrolase: in vitro and in vivo assessment of its efficacy

doi: 10.1101/2024.11.19.624290

Figure Lengend Snippet: In vivo assessment of the efficacy of the combination of micrococcin P1, nisin A and AuresinePlus (MNA) in a skin wound mouse model. The concentration of antimicrobials is the same as D0 in and the treatment was performed from day 1 post-infection (PI) to day 5 PI, imaging and bioluminescence measurements from day 1 was taken prior to initiating treatment. (a) A schematic representation of the experimental setup. (b) In vivo imaging of the bioluminescent signals (in photons per square centimeter per steradian) produced by S. aureus Xen31 over the 7 day experiment in the treated group 1 and untreated group 2 (Ctrl). A relapse of the infection was seen in two mice of the trated group 1, indicated by white asterisks. (c) quantification of the bioluminescent signals. Statistical significance between experimental groups was assessed with Welch’s t-test. Asterisk representation of statistical significance: *p ≤ 0.05; **p ≤ 0.01; ns = not significant.

Article Snippet: To assess the therapeutic potential of the MP1/Nis/PGH combination in vivo , we utilized a murine skin infection model together with a bioluminescent methicillin-resistant S. aureus (MRSA) strain Xen31 (Perkin Elmer, bioluminescent derivative of ATCC 33591).

Techniques: In Vivo, Concentration Assay, Infection, Imaging, In Vivo Imaging, Produced

Journal: bioRxiv

Article Title: An antibiotic-free antimicrobial combination of bacteriocins and a peptidoglycan hydrolase: in vitro and in vivo assessment of its efficacy

doi: 10.1101/2024.11.19.624290

Figure Lengend Snippet: In vivo assessment of the efficacy of the combination of micrococcin P1, nisin A and AuresinePlus in a mouse mastitis model. Representative images of the histological examination of explanted mammary glands. (a) from untreated S. aureus Xen31-infected and uninfected mice. (b-c) Uninfected mouse injected with the antimicrobial vehicle, and infected mice treated with either the antimicrobial vehicle or the antimicrobial combination at the indicated time-points. Note that the injections of the antimicrobials or their vehicles began at day 1 PI and was extended up to day 5 PI. The concentration used was the same as that corresponding to D0 in . Sequential 5 µm thick tissue sections were stained with either hematoxylin and eosin (HE) or Gram stain (Gram) and images were taken at 5x (left panels) or 20x (middle and right panels). Scale bars represent 500 µm in 5x images and 100 µm in 20x images. Insets show magnified images of areas of interest. (d) Barplots showing the of log10-transformed average colony forming units (Log 10 CFU/g ± 1 standard deviation [error bars]) of bacteria recovered from homogenized mammary glands at day 3 PI (left) and day 5 PI (right). Statistical significance relative to the infected control (vehicle) was assessed with Welch’s t-test. Asterisk representation of statistical significance: *p ≤ 0.05; ***p ≤ 0.001.

Article Snippet: To assess the therapeutic potential of the MP1/Nis/PGH combination in vivo , we utilized a murine skin infection model together with a bioluminescent methicillin-resistant S. aureus (MRSA) strain Xen31 (Perkin Elmer, bioluminescent derivative of ATCC 33591).

Techniques: In Vivo, Infection, Injection, Concentration Assay, Staining, Transformation Assay, Standard Deviation, Bacteria, Control