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Mouse inoculation for the detection of non-cultivable gastric tightly spiralled bacteria
E N Mendes1, D M Queiroz, S B Moura
1Laboratório de Pesquisa em Bacteriologia, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
Abstract:
In the present study we compared the inoculation of swine gastric mucus into the stomach of mice, the ureas test and carbolfuchsin-stained smears for the diagnosis of the infection with "Gastrospirillum suis" ("Helicobacter heilmannii" type 1), an uncultivated tightly spiralled gastric bacterium. Fragments obtained from the antral and oxyntic mucosa of the stomach of 50 slaughtered pigs were used for urease test, for carbolfuchsin-stained smears and for obtaining scrapings of mucus for mouse inoculation. The mice were killed by spinal dislocation 10 days after inoculation and fragments of the antral and oxyntic mucosa were used for spiral bacterium identification (urease test and carbolfuchsin-stained smears). Among the methods employed for the diagnosis of "H. heilmannii" infection, the inoculation of gastric mucus into the stomach of mice was the most sensitive and demonstrated bacterial positivity in 31 (62.0%) swine. Direct examination showed tightly spiralled bacteria in the gastric mucosa of only 4 (8.0%) of the 50 pigs studied. Among them, 3 (6.0%) presented a positive preformed urease test. Spiral bacteria were not seen in the gastric mucosa of any control mice. These results show that the use of the mouse inoculation method improved the detection of "H. heilmannii" in swine.
Insights
Mouse inoculation of swine gastric mucus is the most sensitive method for diagnosing Helicobacter heilmannii infections. This technique significantly improved detection rates compared to direct examination or urease tests in swine.
Area of Science:
- Veterinary Microbiology
- Gastroenterology
- Infectious Diseases
Background:
- "Helicobacter heilmannii" type 1, also known as "Gastrospirillum suis", is a tightly spiralled bacterium found in the gastric mucosa.
- Accurate diagnosis of this bacterium in swine is crucial for understanding its epidemiology and potential transmission.
- Traditional diagnostic methods like urease tests and direct smears have limitations in sensitivity.
Purpose of the Study:
- To compare the diagnostic efficacy of three methods for detecting "Helicobacter heilmannii" (type 1) in swine.
- To evaluate the sensitivity of mouse inoculation, urease tests, and carbolfuchsin-stained smears.
- To identify the most reliable method for diagnosing "H. heilmannii" infection in pigs.
Main Methods:
- Gastric mucus and mucosal fragments were collected from 50 slaughtered pigs.
- Methods included urease tests, carbolfuchsin-stained smears, and inoculation of swine gastric mucus into mice.
- Mice were examined for spiral bacteria 10 days post-inoculation using urease tests and stained smears.
Main Results:
- Mouse inoculation demonstrated bacterial positivity in 62.0% (31/50) of swine, significantly higher than other methods.
- Direct examination of gastric mucosa revealed spiral bacteria in only 8.0% (4/50) of pigs.
- A positive preformed urease test was observed in 6.0% (3/50) of pigs.
Conclusions:
- Mouse inoculation of swine gastric mucus is the most sensitive diagnostic method for "Helicobacter heilmannii" (type 1) infection in swine.
- This improved detection rate highlights the value of the mouse model for identifying gastric spiral bacteria.
- The findings suggest that conventional methods may underestimate the prevalence of "H. heilmannii" in swine populations.