Somying Tumwasorn

Human-Derived Probiotic Lactobacillus reuteri Demonstrate Antimicrobial Activities Targeting Diverse Enteric Bacterial Pathogens

Lactobacillus reuteri is a commensal-derived anaerobic probiotic that resides in the human gastrointestinal tract. L. reuteri converts glycerol into a potent broad-spectrum antimicrobial compound, reuterin, which inhibits the growth of gram-positive and gram-negative bacteria. In this study, we compared four human-derived L. reuteri isolates (ATCC 55730, ATCC PTA 6475, ATCC PTA 4659 and ATCC PTA 5289) in their ability to produce reuterin and to inhibit the growth of different enteric pathogens in vitro. Reuterin was produced by each of the four L. reuteri strains and assessed for biological activity. The minimum inhibitory concentration (MIC) of reuterin derived from each strain was determined for the following enteric pathogens: enterohemorrhagic Escherichia coli, enterotoxigenic E. coli, Salmonella enterica, Shigella sonnei and Vibrio cholerae. We also analyzed the relative abilities of L. reuteri to inhibit enteric pathogens in a pathogen overlay assay. The magnitude of reuterin production did not directly correlate with the relative ability of L. reuteri to suppress the proliferation of enteric pathogens. Additional antimicrobial factors may be produced by L. reuteri, and multiple factors may act synergistically with reuterin to inhibit enteric pathogens.

Molecular Epidemiology and Outcome of Helicobacter pylori Infection in Thailand: a Cultural Cross Roads

Background.  Thailand is at the cultural cross roads between East and South Asia. It has been suggested that this is also the region where the predominant Helicobacter pylori (H. pylori) genotype changes from East Asian to South Asian.

Ten-day sequential therapy of Helicobacter pylori infection in Thailand.

OBJECTIVES:Antimicrobial resistance has decreased eradication rates of Helicobacter pylori worldwide. The objective of this study was to determine whether a sequential therapy regimen is effective in eradicating H. pylori in adults with nonulcer dyspepsia or peptic ulcer disease in Thailand.METHODS:A total of 115 patients with dyspepsia or peptic ulcer were enrolled in the study. 14C-urea breath test, upper endoscopy, rapid urease test, bacterial culture, and antibiotic resistance assessment were conducted during the course of the treatment. In all, 115 patients underwent a 10-day sequential regimen, which consisted of lansoprazole (30 mg) plus amoxicillin (1 g) twice a day for 5 days, then lansoprazole (30 mg) with metronidazole (500 mg) twice a day, and clarithromycin (1,000 mg) once a day for another 5 consecutive days. Successful eradication was evaluated by negative urea breath test at least 4 weeks after stopping treatment.RESULTS:Successful eradication was achieved in 106 of 115 patients (95%). All patients completed the treatment, without any dropouts. Mild adverse effects included headache and palpitations. The prevalence rate of clarithromycin-resistant H. pylori was found to be 6.1%.CONCLUSIONS:The 10-day sequential treatment for H. pylori is well tolerated and provides a high eradication rate. This regimen can overcome the emergence of antibiotic resistance and may have a role as a first-line treatment for H. pylori infection in Thailand.

Sequential therapy in clarithromycin-sensitive and -resistant Helicobacter pylori based on polymerase chain reaction molecular test

Background and Aim:  The present study was designed to determine the eradication rate of 10 day sequential therapy in genotypic clarithromycin‐resistant Helicobacter pylori group identified by molecular polymerase chain reaction (PCR) detection in Thai patients.

Lactobacillus saerimneri and Lactobacillus ruminis: novel human‐derived probiotic strains with immunomodulatory activities

Human-derived lactobacilli were isolated from fecal samples of healthy volunteers. Forty-six isolates from different volunteers were selected and investigated for their immunomodulatory properties. Conditioned medium from each isolate was assessed for its effect on tumor necrosis factor (TNF) production in lipopolysaccharide-activated THP-1 monocytes. Of 46 Lactobacillus isolates, 12 significantly inhibited TNF production in varying magnitude. Lactobacillus strain TH58 displayed the most potent TNF-inhibitory activity (70% inhibition). In contrast, Lactobacillus strain TH14 exhibited immunostimulatory property by activating TNF production in THP-1 monocytes. Lactobacillus TH14 induced nuclear factor-kappaB (NF-kappaB) activation in the absence of lipopolysaccharide stimulation, whereas Lactobacillus TH58 had no effect on NF-kappaB signaling, irrespective of lipopolysaccharide stimulation. Strain TH58 was identified as Lactobacillus saerimneri and strain TH14 as Lactobacillus ruminis by sequence analysis of their 16S rRNA genes. This is the first report of a human isolate of L. saerimneri with TNF-inhibitory activity and L. ruminis, an indigenous species to humans, with TNF stimulatory activity. Our data suggest the potential use of these two strains as immunoprobiotic candidates.

Gastric mucosal cytokine levels in relation to host interleukin-1 polymorphisms and Helicobacter pylori cagA genotype

Objective The outcome of a Helicobacter pylori infection is related in part to interrelationships among H. pylori virulence factors and the H. pylori-induced mucosal response. The host inflammatory response is partly governed by polymorphisms in pro-inflammatory genes. Material and methods Cytokine levels (interleukin (IL)-1β, IL-6 and IL-8) were examined in H. pylori-infected and uninfected normal-appearing mucosa from patients with non-ulcer dyspepsia (NUD), margins of gastric ulcers and cancer tissues. Cytokine levels were compared with cagA genotypes and host interleukin (IL)-1 polymorphisms. Results The study comprised 168 Thai patients. All infected patients possessed anti-CagA antibody. Gastric mucosal IL-8 levels were significantly higher in H. pylori-positive cases than in -negative cases in all three tissue types (e.g. 1115 versus 217 pg/mg protein for NUD) (p<0.001). Normal-appearing but H. pylori-infected antral mucosa of patients with cagA type 1a strains had higher IL-8 levels than those with type 2a strains (2632 versus 1036 pg/mg protein) (p<0.005). IL-1B-511T/T carriers had higher antral mucosal IL-1β levels versus non-carriers (pg/mg protein) (T/T=221, T/C=178, C/C=70) (p=0.005). IL-1B-511T/T carriers also had higher IL-1β levels versus non-carriers in H. pylori-negative patients. Conclusions It was found that both the host factors (IL-1 polymorphisms) and bacterial factors (cagA type 1a versus type 2a) influenced gastric mucosal cytokine levels. Future studies should concentrate on interactions among host factors (e.g. genetics and tissue responses) and bacterial and environmental factors.

Lactobacillus plantarum B7 inhibits Helicobacter pylori growth and attenuates gastric inflammation

AIM To determine the anti-Helicobacter property of Lactobacillus plantarum B7 (L. plantarum) B7 supernatants in vitro and the protective effects of L. plantarum B7 on serum tumor necrosis factor-alpha (TNF-α), gastric malondialdehyde (MDA) level, apoptosis, and histopathology in Helicobacter pylori (H. pylori)-induced gastric inflammation in rats. METHODS In vitro, the inhibition of H. pylori growth was examined using L. plantarum B7 supernatants at pH 4 and pH 7 and at the concentration of 1×, 5× and 10× on plates inoculated with H. pylori. The inhibitory effect of H. pylori was interpreted by the size of the inhibition zone. In vitro, male Sprague-Dawley rats were randomly divided into four groups including group 1 (control group), group 2 (H. pylori infected group), group 3 (H. pylori infected with L. plantarum B7 10(6) CFUs/mL treated group) and group 4 (H. pylori infected with L. plantarum B7 10(10) CFUs/mL treated group). One week after H. pylori inoculation, L. plantarum B7 10(6) CFUs/mL or 10(10) CFUs/mL were fed once daily to group 3 and group 4, respectively, for one week. Blood and gastric samples were collected at the end of the study. RESULTS In vitro, at intact pH 4, mean inhibitory zone diameters of 8.5 mm and 13 mm were noted at concentrations of 5× and 10× of L. plantarum B7 supernatant disks, respectively. At adjusted pH 7, L. plantarum B7 supernatants at concentrations of 5× and 10× yielded mean inhibitory zone diameters of 6.5 mm and 11 mm, respectively. In the in vitro study, in group 2, stomach histopathology revealed mild to moderate H. pylori colonization and inflammation. The level of gastric MDA and epithelial cell apoptosis were significantly increased compared with group 1. The serum TNF-α level was significant decreased in group 3 compared with group 2 (P < 0.05). In addition, L. plantarum B7 treatments resulted in a significant improvement in stomach pathology, and decreased gastric MDA level and apoptotic epithelial cells. CONCLUSION L. plantarum B7 supernatant inhibits H. pylori growth. This inhibition was dose-dependent and greater at pH 4. Moreover, L. plantarum B7 attenuated H. pylori-induced gastric inflammation.

Anti-inflammatory Properties of Gastric-derived Lactobacillus plantarum XB7 in the Context of Helicobacter pylori Infection

Helicobacter pylori colonization of the gastric epithelium induces interleukin‐8 (IL‐8) production and inflammation leading to host cell damage. We searched for gastric‐derived Lactobacillus with the ability to suppress H. pylori‐induced inflammation.

CagA genotype and metronidazole resistant strain of Helicobacter pylori in functional dyspepsia in Thailand

Background and Aim:  Many previous studies indicated relationship between H. pylori infection and functional dyspepsia (FD) but pathogenesis remains unclear. The aim of this study was to determine relationship between cagA genotype and metronidazole resistant strains of H. pylori in Thai FD patients.

Spindle cell pseudotumor of the brain associated with Mycobacterium haemophilum and Mycobacterium simiae mixed infection in a patient with AIDS: the first case report

BACKGROUND Spindle cell pseudotumors may occur due to mycobacterial infection, especially in immunocompromised hosts including those with AIDS. They have been reported from many body sites; the lymph nodes are predominantly involved, most frequently associated with Mycobacterium avium complex infection. To the best of our knowledge, Mycobacterium-associated spindle cell pseudotumors have not been previously described in the brain stem and in association with mixed mycobacterial infection. CASE REPORT We describe a man with AIDS who presented with right hemiparesis and truncal ataxia. Magnetic resonance imaging revealed enhancing nodular lesions at the cerebral peduncle and medulla. A mycobacterial spindle cell pseudotumor was diagnosed on surgical specimens. Blood and brain tissue cultures grew Mycobacterium haemophilum and Mycobacterium simiae. CONCLUSIONS To our knowledge, this is the first case of spindle cell pseudotumor of the brain associated with M. haemophilum and M. simiae mixed infection.