Colonic sterilization for natural orifice translumenal endoscopic surgery (NOTES) procedures: a comparison of two decontamination protocols

Surgical Endoscopy (Impact Factor: 3.31). 08/2009; 23(8):1854-1859. DOI: 10.1007/s00464-008-0295-0

ABSTRACT BackgroundThis study aimed to evaluate the effect of two different sterilization protocols on the bacterial counts in the swine colon
as preparation for natural orifice translumenal endoscopic surgery (NOTES) surgery.

MethodsIn this study, 16 swine were randomized to two different colonic sterilization protocols: low colonic irrigation using 300ml
of a 1:1 dilution of 10% povidone–iodine (Betadine) with sterile saline, followed by 1g of cefoxitin dissolved in 300ml
of saline or two consecutive 300-ml irrigations using a quaternary ammonium antimicrobial agent (Onamer M). Colonic cultures
were taken before colonic cleansing after a decontamination protocol and after completion of the NOTES procedure. The Invitrogen
live/dead bacterial viability kit was used to assess for change in the bacterial load. A qualitative culture of peritoneal
fluid was obtained at the end of the NOTES procedure. Colon mucosal biopsies obtained immediately after the sterilization
procedure and at the 2-week necropsy point were evaluated for mucosal changes.

ResultsProtocol 1 resulted in an average 93% decrease in live colonic bacteria versus 90% with protocol 2 (nonsignificant difference).
After a NOTES procedure, group 1 had a 62% increase in live bacteria and group 2 had a 31% increase (nonsignificant difference).
Peritoneal cultures also were obtained. Bacteria were isolated from the peritoneal fluid of all the animals, and two or more
species were isolated from 75% of the animals. There was no evidence of peritoneal infection at necropsy. Reactive epithelial
changes and mild inflammation were the only pathologic abnormalities. No changes were noted at histologic evaluation of colonic
mucosa after 2weeks, demonstrating that these were temporary changes.

ConclusionColonic irrigation with Betadine and antibiotics are as effective for bacterial decontamination of the swine colon as a quaternary
ammonium compound. The results of this study support the use of either protocol. Despite thorough decontamination, peritoneal
contamination occurs. The significance of this for humans is unknown.