Staphylococcus aureus atcc

Ferric chloride hexahydrate (FeCl₃·6H₂O), Nickel chloride hexahydrate (NiCl₂·6H₂O), sodium hydroxide, methionine, and other chemicals were procured from Merck, Germany. A-375 and HFF cells were obtained from the Pasteur cell bank. Staphylococcus aureus (ATCC 23235), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 15442), and Enterococcus faecalis (ATCC 29212) strains were collected from The Pasteur Institute of Iran.

The used microbial strains were Escherichia coli ATCC (American Type Culture Collection, Manassas, VA, USA) 25922 (E. coli) and Staphylococcus aureus ATCC 25923 (S. aureus). E. coli bacteria were grown in Luria Bertani (LB) broth (ForMedium, Norfolk, UK), overnight, under aerobic conditions at 37 °C using a shaker incubator (VDRL Stirrer 711/CT, Asal S.r.l., Milan, Italy) and S. aureus in Tryptic Soy Broth (TSB) (ForMedium). The number of bacterial cells/mL of both cultures was determined by comparing the optical density (OD₆₀₀) of the sample with a standard curve relating the OD to the cell number [37 (link)].

Clinical isolates of bacterial strains Enterococcus faecium ATCC^® 51559™, Staphylococcus aureus ATCC^® 25923™, Klebsiella pneumoniae ATCC^® 700603, Acinetobacter baumannii ATCC^® 49466™, Pseudomonas aeruginosa ATCC^® 15692™, Enterobacter aerogenes ATCC^® 49469™, methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA; ATCC^® BAA-1720) and Vancomycin-resistant Enterococci (VRE; ATCC 700221) were purchased from American Type Culture Collection (ATCC), (Gaithersburg, MD, USA) and maintained following instructions provided by the supplier. Preparation of bacterial inoculum was performed as described previously [9 ]. Briefly, bacteria were cultured in tryptic soy broth at 37 °C with shaking until the absorbance optical densities measured in the range of 0.2 to 0.6 at a wavelength of 600 nm. The number of colony forming units (CFU) for each strain was estimated based on an OD₆₀₀ = 1.0, which corresponds to 10⁹ CFU/mL. To prepare the inoculum, the bacterial stock solution was diluted with either assay medium or conditioned medium to approximately 100 CFU of bacteria/mL. For each experiment, the actual CFU of each inoculum was determined by preparing serial dilutions and plating onto tryptic soy broth agar plates.

Antimicrobial experiments were performed with standard laboratory strains: a Gram-positive strain—Staphylococcus aureus ATCC (American Type Culture Collection) 6538, a Gram-negative strain—Pseudomonas aeruginosa ATCC 27853, and a yeast model—Candida albicans ATCC 90028, all from Collection of Microorganisms stock-cultures of the Department of Microbiology, Faculty of Pharmacy and Biochemistry University of Zagreb (MFBF). Additionally, clinical S. aureus strains were included in the experiments—a methicillin sensitive (MSSA MFBF 10663) and a methicillin resistant strain (MRSA MFBF 10679). All microbial media were purchased from Merck (Darmstadt, 64297, Germany). Gentamicin sulphate (Sigma-Aldrich, St. Louis, MO, USA) and nystatin (Pliva, Zagreb, Croatia) were used as a susceptibility quality control of strains and the method.

We evaluated Gram positive bacteria and Gram negative bacteria from the Tropical Cultures Collection (CCT, Campinas, SP, Brazil), American Type Culture Collection (ATCC, Manassas, VA) and of clinical origin, being: Bacillus subtilis CCT 0516, Pseudomonas aeruginosa ATCC 8027, Pseudomonas aeruginosa ATCC 23243, Staphylococcus aureus ATCC 25619, Staphylococcus aureus ATCC 25925, Escherichia coli 2536, Escherichia coli 101, Escherichia coli 103, Escherichia coli 104, Escherichia coli 105 and Escherichia coli 108.

The antimicrobial activity of ethanol extract of propolis was tested against four reference strains of bacteria: Staphylococcus aureus ATCC 25923, S. aureus ATCC 29213, S. epidermidis ATCC 12228, and S. epidermidis ATCC 35984 (American Type Culture Collection, Manassas, VA, USA). The anti-staphylococcal potential of the propolis sample was also investigated against six MSSA, and three MRSA isolates from patients with different infections (Table 2). S. epidermidis ATCC 35984, a strongly adherent, slime-producing strain, was employed as a model for biofilm studies. S. aureus and S. epidermidis strains were routinely grown on Luria-Bertani Agar (LA, Sigma Aldrich, Schnelldorf, Germany) and Brain Heart Infusion Agar (BHA, Becton Dickinson and Company, Franklin Lakes, NJ, USA). The Minimum Inhibitory Concentration (MIC) was determined using a liquid medium—Mueller–Hinton Broth 2 (MHB2, Sigma Aldrich, Poland). For biofilm formation, TBS liquid medium supplemented with 2.5% of glucose was used (Becton Dickinson and Company, Franklin Lakes, NJ, USA).