Alba Edith Vega

Antimicrobial activity of Artemisia douglasiana and dehydroleucodine against Helicobacter pylori.

ETHNOPHARMACOLOGICAL RELEVANCE The increasing resistance of Helicobacter pylori to antibiotics demands the search for novel compounds from plant based sources. Artemisia douglasiana Besser is widely used in Cuyo region (Argentina) as folk medicine for the treatment of gastric ailments. AIM OF STUDY Based on our previous studies that Artemisia douglasiana exert cytoprotective actions against ethanol-induced gastric mucosal injury we assayed the anti-Helicobacter pylori effect of the Artemisia douglasiana extract and its active compound, dehydroleucodine. MATERIALS AND METHODS The in vitro anti-bacterial activity of Artemisia douglasiana extract and its active compound, dehydroleucodine were determined against one standard strain and six clinical isolates of Helicobacter pylori by using the agar dilution methods. RESULTS The results showed that both dehydroleucodine and Artemisia douglasiana extract had activity against the microorganism with MICs between 1-8 and 60-120 mg/L, respectively. CONCLUSIONS Artemisia douglasiana may be a useful alternative treatment strategy principally in eradication of metronidazole and clarithromycin-resistant strain.

Molecular characterization and susceptibility testing of Helicobacter pylori strains isolated in western Argentina

OBJECTIVE To characterize Helicobacter pylori isolates from western Argentina using virulence markers and antimicrobial susceptibility patterns in order to assess the association between virulent genotypes, antimicrobial resistance, and disease. DNA fingerprinting was also evaluated for the segregation of virulent or resistant strain clusters. METHODS Genotyping of 299 H. pylori isolates was performed by PCR using specific primers for the cagA, vacA and iceA genes. Random amplification of polymorphic DNA (RAPD)-PCR and rep-PCR genetic clustering were assessed using five random primers and BOXA1R and ERIC primers, respectively. Resistance to clarithromycin (Cla) and metronidazole (Mtz) was assessed by the agar dilution method. RESULTS It was observed that 40.8% of the genotypes were cagA-positive; 66.9% were vacA s1m1 genotype and the iceA1 allele was found in 40.8%. A significant correlation (p=0.0000) was observed between cagA positivity and vacA s1m1/iceA1 genotypes. Triple virulent genotypes were statistically associated with peptic ulcer (PU) (p=0.0001) and Cla resistance (p=0.0000). RAPD fingerprints obtained with AO2 primers identified clusters that were strongly associated with PU, virulence markers, and resistance to Cla and Mtz. CONCLUSIONS The H. pylori isolates that harbored two or three virulence markers were more resistant to Cla and Mtz. Combined analysis of virulent genotypes and resistance patterns may permit identification of high-risk patients to prevent PU later in life or to avoid antimicrobial treatment failure.

Growth of Helicobacter pylori in Medium Supplemented with Cyanobacterial Extract

ABSTRACT Solid and liquid media supplemented only with a cyanobacterial extract (CE) and free of fetal calf serum (FCS), blood, and its derivatives support the growth of Helicobacter pylori. A total of 11 strains of H. pylori isolated from gastric biopsy samples were successfully subcultured in Mueller-Hinton agar supplemented with 0.4% CE. When this medium was used for primary isolation of H. pylori, a low isolation rate (30%) was observed because of the abundant growth of contaminants. The growth kinetics of eight isolates and H. pylori reference strain NCTC 11638 in Mueller-Hinton broth (MHB) supplemented with 0.7% CE were estimated by use of growth parameters, and the results were compared with those obtained with MHB-5% FCS. For four strains the cellular concentrations obtained with CE were statistically higher (P < 0.05) than those obtained with FCS, and in some cases these values were similar to the highest values reported in the literature. Depending on the strain, the specific growth rates obtained with CE were similar to or increased compared with those obtained with FCS. The replacement of FCS by CE in H. pylori cultures would facilitate the retrieval of cultures with high cellular densities as a source of cellular and extracellular proteins free of serum. Also, CE has advantages over conventional supplements, such as easier conservation and compliance with the pressing tendency at present to avoid the use of products derived from animals.

Perfil serológico de la infección por Helicobacter pylori en la población de San Luis (Argentina)

Se realizo un estudio seroepidemiologico de inmunoglobulina G (IgG) anti-H. pylori por analisis de inmunoabsorcion ligado a enzimas (ELISA) (Meridian Diagnostics, EE.UU.) en 509 sueros, pertenecientes a 314 individuos asintomaticos: ninos (n = 124), adolescentes (n = 74) y adultos (n = 116) y en 195 sueros de individuos sintomaticos: ninos (n = 38) y adultos (n = 157). El punto de corte fue redefinido y establecido en DO450 = 0,050. El porcentaje de seropositividad no fue significativamente diferente entre los grupos de adultos estudiados (75,9 y 80,2%, respectivamente) (p We performed a seroepidemiological study of anti-Helicobacter pylori IgG by a commercial enzyme immunoassay kit (Meridian Diagnostics, USA) in 509 serum samples from 314 randomly selected asymptomatic subjects from among the population, and grouped into children (n = 124), adolescents (n = 74) and adults (n = 116), and in 195 serum samples from subjects presenting clinical gastric symptoms, grouped into children (n = 38) and adults (n = 157). The cut-off value was redefined and set at OD450 = 0.050. The percentage of seropositive individuals was not significantly different between the two groups of adults studied (75.9% and 80.2%, respectively) (p

Gastroprotective effects and antimicrobial activity of Lithraea molleoides and isolated compounds against Helicobacter pylori.

ETHNOPHARMACOLOGICAL RELEVANCE Lithraea molleoides (Vell.) Engl. (Anacardiaceae) is a medicinal plant traditionally used in South America to treat various ailments, including diseases of the digestive system. AIM OF THE STUDY To evaluate the in vivo antiulcer and antimicrobial activities against Helicobacter pylori of L. molleoides and its isolated compounds. MATERIALS AND METHODS Methanolic extract 250 and 500 mg/kg, (LmE 250 and LmE 500, respectively) and infusions, 10 g and 20 g en 100mL (LmI 10 and LmI 20, respectively) of L. molleoides was evaluated for antiulcer activity against 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol-induced gastric ulcers in rats. The degree of erosion in the glandular part of the stomach was assessed from a scoring system. Acute toxicity in mice was also evaluated. The antiulcer effect of the isolated compounds (catechol, mannitol, rutin, gallic acid, ferulic acid and caffeic acid, 100mg/kg) was evaluated against absolute ethanol-induced gastric ulcers in rats. The anti-Helicobacter pylori activity of L. molleoides and isolated compounds was performed using broth dilution methods. RESULTS The LmE 250, LmE 500, LmI 10 and LmI 20 produced significant inhibition on the ulcer index in 0.6N HCl, 0.2N NaOH, 200mg/kg acetilsalicilic acid and absolute ethanol- induced gastric ulcers in rats. The isolated compounds, catechol, mannitol, rutin, ferulic acid and caffeic acid were active in absolute ethanol- induced gastric ulcers in rats. L. molleoides and different compounds showed antimicrobial activity in all strains tested. The lowest MIC value (0. 5 μg/mL) was obtained with catechol in six of eleven strains assayed. No signs of toxicity were observed with doses up to 2g/kg in an acute toxicity assay. CONCLUSION These findings indicate that L. molleoides displays potential antiulcerogenic and antimicrobial activities and the identification of active principles could support the use of this plant for the treatment of digestive affections.

Genotypic, phenotypic, and clinical characteristics of isolates ofHelicobacter pylori from San Luis, Argentina

ThevacA andcagA genotypes ofHelicobacter pylori exhibited distinct geographic distribution and correlation with severity of disease. In the above genotypes (obtained from 150H. pylori-positive patients — 139 with gastritis, 10 with ulcer and 1 patient with gastric cancer) combinationsvacA s1/m1 and s2/m2 were detected using PCR in 75 and 25% of isolates, respectively, in patients with chronic gastritis. The of s1/m1 and s2/m2 combinations were also detected from ulcers (60 and 40%, respectively). ThecagA was detected in 30% of isolates. Concentrated culture supernatants of 7 (64%) out of 11H. pylori strains induced vacuolization in Vero cells in titers ranging from 1 : 5 to 1 : 40. ThevacA s1 genotype was significantly associated with, but not predictive of the presence of vacuolating cytotoxin activity and thecagA gene.