E coli atcc 8739

Reference strains (E. faecium ATCC 19436, S. aureus ATCC 25923, S. aureus ATCC 6538, B. cereus ATCC 11778 and E. coli ATCC 8739) are from American Type Culture Collection, P. aeruginosa, MRSA 39, MSSA 60 are from the Laboratory of Microorganisms and Active Biomolecules Collection, University of Tunis El Manar, Tunis, Tunisia and Salmonella spp IPT13 is from Pasteur Institute of Tunis. Fungal strains A. niger, A. flavus and P. expansum are from the Laboratory of Microbial Ecology and Biotechnology, University of Paul Cezanne, France.

The Gram-positive S. aureus ATCC 6538, E. faecalis ATCC 29212 and B. subtilis ATCC 6633 and the Gram-negative P. aeruginosa ATCC 27853 and E. coli ATCC 8739 were purchased from American Type Culture Collection (ATCC, Virginia, USA). Glycerol stocks were streaked on LB agar to obtain 24-h cultures to be used for all further studies.
Monospecific biofilm development was assessed at two different times of exposure, i.e., 15 min and 24 h. The textile materials were cut in equal circular samples of 8 mm and sterilized by autoclaving at 121 °C for 15 min. The sterile samples were then immersed in 1 mL of microbial suspensions of ~10⁷ colony forming units (CFU)/mL performed in sterile saline and left in contact for 15 min and 24 h, respectively. After this interval, microbial suspensions incubated with the tested samples were vortexed and further serially ten-fold diluted, and 10 µL of each serial dilution were plated in triplicate on LB agar. After 24 h of incubation at 37 °C, viable cell counts were performed, and the number of CFU/mL for each sample was established.