An Accredited ex vivo Porcine Mucosal Model

Aim: Mucous membrane is the moist lining of body cavities that communicate with the exterior. These tissues line the tongue, gastrointestinal (GI) tract, nasal passages, urinary tract and vaginal canal. Pressure applied to this tissue can render it ischemic and lead to ulceration. Mucosal tissues are especially vulnerable to pressure from medical devices, such as oxygen tubing, endotracheal tubes, bite blocks, orogastric and nasogastric tubes, urinary catheters and faecal containment devices. This study aimed to determine the reproducibility of Pseudomonas aeruginosa biofilms on ex vivo porcine mucosal tissue and to develop a platform for topical and aerosolised treatments for infected mucosal wounds in line with ISO 17025.

Method: P. aeruginosa was used to develop biofilms on ex vivo porcine mucosal tissue combined with a protein-based medium over 72 hours. Planktonic organisms were removed by washing prior to treatment. Following washing, individual treatments were applied to the tissue for 24 hours ± 2 hours at 37 °C ± 2 °C. Remaining viable organisms were recovered by sonication and resultant suspensions were plated onto agar.

Results: An average of 6.57 ± 0.14 Log10CFUmL-1 was recovered from untreated tissue. An average of 1.48 ± 0.41 Log10CFUmL-1, 4.12 ± 0.40 Log10CFUmL-1  and 5.82 ± 0.31 Log10CFUmL-1  was recovered from the topical agent A, B and C, respectively. No viable microorganisms were recovered from the positive control samples or the tissue sterility samples.

Conclusion: There is an increasing need to design and develop new platforms to provide real-world, challenging anti-biofilm efficacy test methods to differentiate between antimicrobial products. The use of ex vivo porcine mucosal tissue mimics the way microorganisms attach to surfaces in a clinical setting. This model may also apply to other types of wound which are not within the mucosa as wound healing is the same in mucosa as it is in the skin, except for the formation of scar tissue.  

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