Effectivity of current sterility methods for transgastric access NOTES procedures: results of a randomized porcine study

Background: Natural orifice transluminal endoscopic surgery (NOTES) is an emerging transluminal technique through which interventions are performed by entering the abdominal cavity through a natural orifice such as the stomach. Infection is a potential risk of the procedure and the potential pathogens are different than with skin incisions. Currently, there is limited data regarding prophylactic treatment with antibiotics, topical antimicrobial lavage and proton-pump-inhibitor (PPI) therapy for transgastric NOTES.

Aim/Methods: Prospective randomized survival study with 16 pigs (25–30 kg). Eight pigs received the following preparation: 40 mg Esomeprazole i.v. 30-min. prior to intervention; mouth lavage with Chlorhexidine 2% (100 ml), gastric lavage with 200 ml Chlorhexidine (200 ml), followed by gastric irrigation with diluted antibiotic containing Neomycin and sterile saline solution as well a single-shot application of Cefuroxim i.v. (1,5 g) and Metronidazol i.v. (500 mg). The control group (n = 8) underwent gastric cleansing with sterile saline solution. Gastrotomy was closed after two hours. Prior to closure peritoenal biopsy, multiple smears and dilutions for cultures were taken and incubated. The pigs were sacrified after 14 days. Biopies, smears and cultures as well as WBC and serum CRP were taken in the follow-up. Bacterial load was expressed in Colony-forming units (CFU's).

Results: 15/16 pigs survived the follow-up of 14 days. one pig (control group) underwent gall bladder perforation with gross peritonitis and had to be sacrified after three days. 2/15 swine presented minor clinical signs of infection (all control group). The median serum CRP's were 5,7 g/dl (therapy group) and 17,2 g/dl (control) (p = 0,17). Peritoneal bacterial growth was seen in 1/8 pigs of the therapy group and 8/8 pigs of the control group (p = 0,002). The bacterial load was 20 CFU's/cm² (therapy) vs. 3,2 × 105 CFU's/cm² (control) (p = 0,023). E. coli and Enterococcus were the most common organisms. Major peritonitis was seen in one, local peritonitis and ahesions were seen in another two pigs, all from the control group.

Conclusion: The use of intravenous antibiotics in addition to topical antimicrobial lavage of mouth/ stomach and PPI-therapy effectively decreases the peritoneal bacterial load to almost zero and this was associated with a significant lower peritoneal infection rate when compared to saline only lavage.