Bacteria rapidly colonize and modulate healing of gastric ulcers in rats.
The stomach is generally regarded as an environment that is not conducive to bacterial colonization. In this study, we examined the possibility that this changes significantly when an ulcer has formed and that colonization of ulcers interferes with the normal healing process. Gastric ulcers were induced by serosal application of acetic acid. The relationship between ulcer healing and bacterial colonization was examined. The effects of antibiotics, induction of Lactobacillus colonization, and selective colonization with an antibiotic resistant strain of Escherichia coli on ulcer healing were examined. Within 6-12 h of their induction, gastric ulcers were colonized by a variety of bacteria, with gram-negative bacteria predominating. Suppression of colonization with antibiotics resulted in marked acceleration of healing. Induction of Lactobacillus colonization also accelerated ulcer healing. The beneficial effects of antibiotics were reversed through selective colonization with antibiotic-resistant E. coli. Bacterial colonization occurred irrespective of the method used to induce the ulcer. This study demonstrates that colonization of gastric ulcers in rats occurs rapidly and significantly impairs ulcer healing. This effect appeared to be primarily attributable to gram-negative bacteria.
Department of Pharmacology and Therapeutics, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
S N
SN
Elliott
A
A
Buret
W
W
McKnight
M J
MJ
Miller
J L
JL
Wallace
D019342:Acetic Acid; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001414:Bacitracin / Q000627:therapeutic use*; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development*; D005744:Gastric Acid / Q000378:metabolism; D007778:Lactobacillus / Q000187:drug effects / Q000254:growth & development*; D008297:Male; D009288:Naproxen; D010418:Pentagastrin / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013276:Stomach Ulcer / Q000139:chemically induced / Q000382:microbiology* / Q000503:physiopathology*; D013307:Streptomycin / Q000627:therapeutic use*; D013997:Time Factors; D014945:Wound Healing / Q000187:drug effects
D000900:Anti-Bacterial Agents; D001414:Bacitracin; D009288:Naproxen; D010418:Pentagastrin; D019342:Acetic Acid; D013307:Streptomycin