In vitro and in vivo inhibition of Helicobacter pylori by Lactobacilllus paracasei HP7 / 한국실험동물학회지

The efficacy of standard therapeutic strategies for Helicobacter pylori (H. pylori) infection is decreasing over time due to the emergence of drug-resistant strains. As an alternative, the present study investigated the capacity of Lactobacilllus paracasei (L. paracasei) HP7, isolated from kimchi, to inhibit H. pylori growth. The effects of L. paracasei HP7 on H. pylori adhesion and H. pylori-induced inflammation were examined in AGS human gastric adenocarcinoma epithelial cells and a mouse model of H. pylori SS1 infection. L. paracasei HP7 reduced H. pylori adhesion to AGS cells and suppressed the inflammatory response in infected cells by downregulating interleukin-8. H. pylori colonization in the stomach of C57BL/6 mice was demonstrated by rapid urease test, and results showed significant decrease in mice post-treated with L. paracasei HP7. Additionally, L. paracasei HP7 decreased gastric inflammation and epithelial lesions in the stomach of H. pylori-infected mice. These results demonstrate that L. paracasei HP7 treatment can inhibit H. pylori growth and is thus a promising treatment for patients with gastric symptoms such as gastritis that are caused by H. pylori infection.

Anti-Helicobacter pylori activity and inhibition of gastritis by Allium hookeri extract / 한국실험동물학회지

Allium hookeri is widely consumed plant as a vegetable and herbal medicine in southeastern Asia. Allium hookeri has been reported antioxidant, improvement of bone health and antidiabetic effects. In the present study, we investigated the potential inhibitory effect of Allium hookeri extract (AHE) on Helicobacter pylori. The in vitro anti-bacterial activities of AHE were determined by disk agar diffusion method. Also, the inhibition effect of the AHE on H. pylori infection was investigated using a mouse model. H. pylori colonization was confirmed by rapid urease tests, as described previously. Mucosal damage was evaluated grossly and histologically according to previously described criteria. As the results of the disk agar diffusion assay, CLR, AMX and MTZ inhibited the bacterial growth with inhibition zone of 19.2, 15.2 and 7.5 mm, respectively. AHE 100 µg/mL showed an inhibition zone value of 20.6 mm. Rapid urease tests of the mice stomachs demonstrated a significant reduction in H. pylori colonization. In addition to the therapeutic effect against H. pylori infection, the AHE reduced mucosal inflammation and epithelial damages in the stomach of H. pylori-infected mice. These results demonstrate that the AHE successfully cured an H. pylori infection and treated the H. pylori infection. This AHE could be a promising treatment for patients with gastric complaints including gastritis caused by H. pylori.

Detection of Helicobacter felis in a cat with gastric disease in laboratory animal facility / 한국실험동물학회지

A 3-month-old male cat in the animal facility was presented for investigation of anorexia and occasional vomiting. We collected the specimens from gastroscopic biopsy and stool collection. The gastroscopic biopsy specimens were tested using a rapid urease test, CLO Helicobacter-detection kits. Stool specimens were gathered and evaluated using the commercially available SD Bioline H. pylori Ag kit according to the manufacturer's instructions. Genomic DNAs from gastroscopic biopsy and stool specimens of the cat were extracted and submitted to the consensus PCR to amplify Helicobacter rpoB gene. Then the DNAs from gastroscopic biopsy and stool specimens were conducted a multiplex species-specific PCR to amplify urease B gene for H. heilmannii, H. pylori and H. felis. As the results, the rapid urease test with gastroscopic biopsy was revealed positive reaction. The result of H. pylori Stool Ag assay was one red line, negative for H. pylori. The gastroscopic biopsy and stool specimen were positive reactions by the consensus PCR reaction using the RNA polymerase beta-subunit-coding gene (rpoB) to detect Helicobacter species. By multiplex species-specific PCR with gastroscopic biopsy and stool specimens, no amplification products corresponding to either H. heilmannii or H. pylori were detected, but the specimens tested were positive for H. felis. This case was confirmed as gastroenteric disease induced by H. felis infection. On our knowledge, this is a very rare report about H. felis-induced gastroenteric disease in cat and may provide a valuable data on the study of feline Helicobacter infection.

Comparison of three diagnostic assays for the identification of Helicobacter spp. in laboratory dogs / 한국실험동물학회지

A number of Helicobacter species may confound experimental data because of their association with disease progressing in various kinds of laboratory animals. Screening of Helicobacter species is particularly desirable, because they are prevalent in commercial and research animal facilities. The aim of the present study was to compare three diagnostic methods [e.g. Helicobacter stool antigen kit (HpSA), polymerase chain reaction (PCR) and rapid urease test (RUT)] for the identification of Helicobacter spp. in stools or gastric biopsy specimens collected from eight dogs suffering from gastritis. The gastroscopic biopsy specimens were tested using RUT and PCR, while stool specimens were evaluated using both HpSA and PCR. DNAs from the gastric biopsies and stool specimens were analyzed by both a consensus PCR that amplified the RNA polymerase beta-subunit-coding gene (rpoB) of Helicobacter spp. and a species-specific PCR to amplify the urease B gene of Helicobacter heilmannii, Helicobacter pylori, and Helicobacter felis. Helicobacter spp. were detected in 62.5% of the dogs, while H. heilmannii and H. felis were identified in 37.5 and 25% of the dogs, respectively. The HpSA did not efficiently detect Helicobacter spp. in the stool samples compared to the RUT and PCR assays, both of which successfully detected Helicobacter spp. in the two sample types. Finally, we recommend that consensus PCR with stool specimens could be used before the species-specific PCR for identifying Helicobacter species in laboratory dogs.

Diagnosis of Mycoplasma hyorhinis infection in pigs by PCR amplification of 16S-23S rRNA internal transcribed spacer region / 동물의과학연구지

Mycoplasma hyorhinis (M. hyorhinis) is considered an etiological agent of arthritis in suckling pigs. Recently, some M. hyorhinis strains were shown to produce pneumonia that is indistinguishable from the mycoplasmosis caused by M. hyopneumoniae. In this study, we developed a sensitive and specific PCR assay to detect M. hyorhinis and applied the developed PCR assay for detection of Mycoplasma infection in clinical piglets infected with M. hyorhinis. We developed a new PCR assay using a M. hyorhinis-specific primer pair, Mrhin-F and Mrhin-R, designed from the Mycoplasma 16S-23S rRNA internal transcribed spacer (ITS) region. The primers and probe for the assay were designed from regions in the Mycoplasma 16S-23S rRNA ITS unique to M. hyorhinis. The developed PCR assay was very specific and sensitive for the detection of M. hyorhinis. The assay could detect the equivalent of 1 pg of target template DNA, which indicates that the assay was very sensitive. In addition, M. hyorhinis PCR assay detected only M. hyorhinis and not any other Mycoplasma or bacterial spp. of other genera. The new developed PCR assay effectively detected M. hyorhinis infection in pigs. We suggest that this PCR assay using a M. hyorhinis-specific primer pair, Mrhin-F and Mrhin-R, could be useful and effective for monitoring M. hyorhinis infection in pigs.

Usefulness of a Helicobacter pylori stool antigen test for diagnosing H. pylori infected C57BL/6 mice / 한국실험동물학회지

Among several diagnostic tests, a Helicobacter pylori stool antigen (HpSA) test may offer a useful noninvasive method for diagnosing infection without sacrificing animals. In this study, male C57BL/6 mice (n=6) were infected with H. pylori ATCC 49503 (1x10(8) CFU/mouse) by intragastric inoculation three times at 2-day intervals, and H. pylori infected stool specimens were collected 1, 3, 5, 7, 14, 21 days after infection to assess reliability of the HpSA test. Five of six specimens were positive at 5-21 days after infection, and the sensitivity of the HpSA test was 83.33%. The presence of H. pylori infection was confirmed by the rapid urease test and genomic DNA polymerase chain reaction (PCR), and showed the same results as the HpSA. However, the rapid urease test and genomic DNA PCR are invasive tests and require animal sacrifice to detect H. pylori in gastric biopsy samples. We suggest that an HpSA test kit would be useful and effective for monitoring H. pylori in various laboratory animals, as H. pylori can be easily monitored without sacrificing animals.

Sensitive and specific identification by polymerase chain reaction of Eimeria tenella and Eimeria maxima, important protozoan pathogens in laboratory avian facilities / 한국실험동물학회지

Eimeria tenella and Eimeria maxima are important pathogens causing intracellular protozoa infections in laboratory avian animals and are known to affect experimental results obtained from contaminated animals. This study aimed to find a fast, sensitive, and efficient protocol for the molecular identification of E. tenella and E. maxima in experimental samples using chickens as laboratory avian animals. DNA was extracted from fecal samples collected from chickens and polymerase chain reaction (PCR) analysis was employed to detect E. tenella and E. maxima from the extracted DNA. The target nucleic acid fragments were specifically amplified by PCR. Feces secreting E. tenella and E. maxima were detected by a positive PCR reaction. In this study, we were able to successfully detect E. tenella and E. maxima using the molecular diagnostic method of PCR. As such, we recommended PCR for monitoring E. tenella and E. maxima in laboratory avian facilities.