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An ex vivo bacteriologic study comparing antiseptic techniques for natural orifice translumenal endoscopic surgery
Marvin Ryou1, Ronen Hazan, Laurence Rahme
1Division of Gastroenterology, Brigham and Women's Hospital, 75 Francis St., Boston, MA 02115, USA.
Background:
NOTES via the gastrointestinal tract raises the specter of intra-peritoneal infection. Various anti-microbial techniques have been employed in animal and human survival studies, including saline lavage, intravenous and topical antibiotics, and povidone-iodine, although there is a paucity of data regarding their general effectiveness.
Aim:
To assess the effectiveness of existing sterilization techniques for NOTES by quantifying and speciating colony-forming units (CFUs) before and after treatment.
Design:
Ex vivo animal studies; bacteriological study.
Methods:
Stomachs and distal colons were harvested en bloc from ten fasted adult white pigs following euthanasia. Half received cefazolin 1 g intravenously prior to killing. Multiple tissue samples were obtained from each resected organ. Each tissue sample was then assigned to one of five treatment arms: (1) normal saline, (2) Betadine, (3) cefazolin/metronidazole suspension, (4) chlorhexidine, (5) no treatment. Fifteen samples were used per arm. After treatment, the mucosal surface of each sample was swabbed and inoculated in normal saline, followed by serial dilutions, which were then plated onto sheep's blood agar plates and incubated under aerobic and anaerobic conditions. CFUs were quantified and speciated.
Results:
Median bacterial density was estimated to be 8.0 × 10(5) CFUs/ml (stomach) and 1.9 × 10(6) CFUs/ml (colon). The predominant organisms were Escherichia coli (stomach) and both E. coli and Enterococcus sp. (colon). Saline and antibiotic suspension lavages caused a 1-log reduction in stomach and colon. Betadine/chlorhexidine lavage resulted in a 4-log reduction. Intravenous antibiotics alone resulted in a 4-log reduction. Combining intravenous antibiotics and either Betadine or chlorhexidine decreased counts to the 10(1) level. By Kruskal-Wallis method, differences were statistically significant (p = 0.001).
Conclusions:
The use of intravenous antibiotics in addition to topical Betadine or chlorhexidine effectively reduced microbial burden in both gastric and colonic mucosa in this porcine model to the 10(1) level.
Insights
Sterilizing gastrointestinal organs for NOTES procedures is crucial. Combining intravenous antibiotics with topical Betadine or chlorhexidine significantly reduces bacterial contamination in porcine stomach and colon models.
Area of Science:
- Gastroenterology
- Surgical Innovation
- Microbiology
Background:
- Transgastric and transcolonic routes for Natural Orifice Transluminal Endoscopic Surgery (NOTES) carry a risk of intra-peritoneal infection.
- Existing antimicrobial strategies, including lavage, antibiotics, and povidone-iodine, have shown variable effectiveness.
- Limited data exists on the general efficacy of these sterilization techniques for NOTES procedures.
Purpose of the Study:
- To evaluate the effectiveness of various sterilization methods for NOTES.
- To quantify and identify bacterial colony-forming units (CFUs) before and after antimicrobial treatments.
- To determine optimal strategies for reducing microbial burden in gastrointestinal tissues.
Main Methods:
- Ex vivo bacteriological study using porcine stomachs and colons.
- Tissue samples were subjected to five treatment arms: saline, Betadine, cefazolin/metronidazole suspension, chlorhexidine, or no treatment.
- Bacterial CFUs were quantified and speciated after incubation under aerobic and anaerobic conditions.
Main Results:
- Baseline median bacterial densities were 8.0 × 10^5 CFUs/ml (stomach) and 1.9 × 10^6 CFUs/ml (colon), with Escherichia coli and Enterococcus sp. as predominant organisms.
- Saline and antibiotic suspension lavages achieved a 1-log reduction; Betadine/chlorhexidine and intravenous antibiotics alone resulted in a 4-log reduction.
- Combination therapy (intravenous antibiotics with Betadine or chlorhexidine) reduced bacterial counts to the 10^1 level, a statistically significant difference (p = 0.001).
Conclusions:
- Topical Betadine or chlorhexidine combined with intravenous antibiotics effectively minimizes microbial load on gastric and colonic mucosa.
- This combination therapy achieved significant bacterial reduction in a porcine model.
- Findings support the use of combined antimicrobial strategies to enhance the safety of NOTES procedures.
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