Escherichia coli atcc 8739

Species identification was performed for all samples, by using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) (Vitek MS Mycobacterium/Nocardia Kit, bioMérieux SA, Marcy L’Étoile, France). Briefly, 1 μL of NTM colonies grown on LJ medium was transferred to a tube containing glass beads and 70% ethanol, vortexed for 15 min, and incubated for additional 10 min at room temperature. The dried pellets were then uniformly dispersed in 70% formic acid and acetonitrile. After centrifugation, 1 μL of the supernatant was transferred to a slide. After drying, 1 μL of CHCA matrix (bioMérieux SA, Marcy L’Eoile, France) was applied and allowed to dry before the analysis. Identification was performed automatically. For calibration and quality control, Escherichia coli (ATCC 8739; American Type Culture Collection, Manassas, VA, USA) was used for each run according to the manufacturer’s protocol [19 (link)].

Pectin powder from citrus was purchased from Daejung Chemicals & Metals Co., Ltd. (Siheung, Korea). Glycerol was obtained from Duksan Pure Chemicals Co., Ltd. (Ansan, Korea). Calcium chloride (CaCl₂) and ZnO nanopowder were purchased from Sigma Aldrich Chemicals (St. Louis, MO, USA). Nutrient broth (NB) was purchased from DB Difco^TM (Sparks, MD, USA). Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538 P were procured from the American Type Culture Collection (ATCC).

Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538 pellets were obtained from the American Type Culture Collection (Microbiologics, MN 56303-USA). The pellets were activated by suspending a single pellet of each microorganism in phosphate buffer (0.1 M) and incubating it at 38°C for 30 minutes. From the buffer, 1mL was transferred to nutrient broth and incubated at 35°C for 24 hours to allow for growth of the bacteria. The levels of inoculum obtained after plating were 5.2x10⁹ cfu/mL for E. coli and 1.5x10⁹ cfu/mL of S. aureus. The inoculum was then stored at -80°C to avoid changes that may affect growth [23 (link)].

Escherichia coli ATCC8739, obtained from the American Type Culture Collection (Manassas, VA, USA), was precultured in tryptic soy broth (TSB; Becton Dickinson Co., Cockeysville, MD, USA); and its cell suspension was plated onto tryptic soy agar (TSA; Becton Dickinson Co., Cockeysville, MD, USA) and cultured at 37 °C.

Escherichia coli ATCC8739 was purchased from the American Type Culture Collection. Adherent invasive E. coli (AIEC) strains were kindly gifted by Professor Christel Neut (Rahmouni et al., 2018 (link)). All strains were cultured in Luria-Bertani (LB) media. Bacteriophage PBPA90 infecting P. aeruginosa was obtained from the Bacteriophage Bank of Korea. The bacteriophage was isolated from Opo Wastewater Facility in Gwangju, Gyeonggi-do, South Korea. The host strain used for the isolation was P. aeruginosa (ATCC13388). An endolysin gene was annotated and named LysPA90 (GenBank accession no. MW815133).

Staphylococcus aureus ATCC^® 6538 (Lot no. 4600502) and Escherichia coli ATCC^® 8739 (Lot no. 380063) were obtained from American Type Culture Collection (University Boulevard, Manassas, VA, USA). The bacterial strains were inoculated separately into 100 mL of Tryptic Soy Broth medium and then incubated at 37.0 ± 1.0 °C for 24 ± 2 h. A loopful from the broth was streaked onto Tryptic Soy Agar medium, and incubated at 37.0 °C for 21 ± 3 h to prepare a fresh culture agar plate. A direct sterile saline solution was prepared by inoculating 3–4 colonies (from each organism plate), then the suspension was adjusted to achieve turbidity that was equivalent to a 0.5 McFarland standard. The inoculum density was standardized using a 0.5 McFarland standard and DensiCHEK© optical device (DensiCHEK plus© SKU Number: 21250; BioMérieux, France). Suspensions containing approximately 1.0 × 10⁸ CFU/mL of Escherichia coli and Staphylococcus aureus were obtained.

To study the antimicrobial activity, standard test strains of microorganisms were used: Bacillus subtilis ATCC 6633 and Staphylococcus aureus ATCC 6538-P, which are obtained from the Republican Collection of Microorganisms (Nur-Sultan, Kazakhstan) and Candida albicans ATCC 10231 and Escherichia coli ATCC 8739, which are obtained from the American Type Culture Collection (ATCC, USA).
Sensitivity studies of microorganisms were performed on standard nutrient media:

  Mueller Hinton medium: Mueller Hinton Agar (М173), HiMedia, India; Mueller Hinton Broth (Mueller Hinton Broth (M391), HiMedia, India [CLSI]

  Fluid Sabouraud medium (M013), HiMedia, India [CLSI]