Trypticase soy broth medium

All Aeromonas isolates were identified at the genus level with a panel of tests according to Martin-Carnahan and Joseph [13 ]. Subsequently, Aeromonas isolates were biochemically typed at complex level by using previously published criteria [14 (link)]. According the Abbott scheme (Voges–Proskauer test, esculin hydrolysis, L-arabinose fermentation and gas production from glucose), each isolate was assigned to one of three traditionally recognized complex of motile Aeromonas spp.: Aeromonas hydrophila, Aeromonas sobria, and Aeromonas caviae.
The following reference strains were used in parallel with test isolates as positive/negative controls for the interpretation of doubtful biochemical reactions: Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Streptococcus agalactiae ATCC 27956, Klebsiella pneumonia ATCC 13883, Citrobacter freundii ATCC 43864, Salmonella enterica subsp. salamae (IZSLER 2009), Salmonella typhimurium ATCC 14028, Proteus mirabilis ATCC 29906, Listeria monocytogenes ATCC 13932.
Stock cultures were maintained at − 20 °C in Trypticase Soy Broth medium (Oxoid, Italy) supplemented with glycerol at 20% (vol/vol).

The hemolytic Gram-positive strains Streptococcus pyogenes ATCC 19615 and Streptococcus pneumoniae ATCC 6303 were cultured on Brain Heart Infusion (BHI, Becton Dickinson GmbH, Heidelberg, Germany) at 37 °C under 5% CO₂ conditions. Escherichia coli ATCC 25922, E. coli ATCC 9637, Staphylococcus aureus ATCC 6538 and ATCC 29213 were routinely cultured on Trypticase Soy Broth medium (Oxoid, Milan, Italy) at 37 °C under aerobic conditions. Listeria monocytogenes DSM 12464, Salmonella enterica serovar typhimurium ATCC 14028 and Salmonella enterica subsp. enterica serovar enteritidis ATCC 13076 were revitalized in BHI broth at 30 °C under aerobic conditions. The probiotic strain Bifidobacterium animalis BB12 (Christian Hansen AS, Hoersholm, Denmark), was grown in Bifidus Selective Medium Broth (BSM, Sigma Aldrich, Milan, Italy) or in Man Rogosa and Sharpe (MRS, Oxoid, Milan, Italy) supplemented with 0.25% L-cysteine (Sigma Aldrich, Milan, Italy) (MRSc) at 37 °C, under anaerobic conditions, and included in every experiment for comparison.

The bile salt hydrolase (BSH)-positive strain Lactobacillus acidophilus DRU, the hydrogen peroxide (H₂O₂) producer Lactobacillus acidophilus ATCC 4356, and the reference strain Lactobacillus rhamnosus GG (ATCC 53103) were routinely cultured in de Man Rogosa and Sharpe (MRS, Biolife, Italy) medium plus 100 mg/L of cycloheximide (Merck, Germany) at 37 °C under anaerobic conditions, using Anaerocult C (Merck, Milan, Italy). The haemolytic positive strains Streptococcus pyogenes ATCC 19615 and Streptococcus pneumoniae ATCC 6303 were cultured on Brain-Heart Infusion (BHI, Becton Dickinson GmbH, Germany) at 37 °C under 5% CO₂ conditions. Escherichia coli 555, E. coli ATCC 25922, E. coli ATCC 700414, and Staphylococcus aureus ATCC 6538 were routinely cultured on Trypticase Soy Broth medium (Oxoid, Milan) at 37 °C, under aerobic conditions. Listeria monocytogenes DSM 12464 strain was reactivated in BHI broth at 30 °C. Gardnerella vaginalis ATCC 14018 was cultured on Casman’s medium base added of 5% of rabbit blood (VWR, Milan, Italy) at 37 °C. Candida albicans ATCC 10231, Candida krusei ATCC 14243, Candida glabrata ATCC 90030, Candida parapsilosis ATCC 90018, Candida lusitaniae ATCC 200951 and Candida tropicalis ATCC 13803 were cultured on Yeast Mold Broth (Conda, Madrid, Spain) at 28 °C in aerobic conditions.