Antimicrobial susceptibility of Helicobacter pylori and mechanisms of clarithromycin resistance in strains isolated from patients in Uruguay.

The prevalence and mechanisms of antibiotic resistance of Helicobacter pylori have not yet been investigated in Uruguay. The objective of this study was to assess the susceptibility of H. pylori to the most frequently used antibiotics and to determine the mechanism of resistance to clarithromycin. Seventy-nine isolates were obtained from gastric biopsies of 50 adult patients during two periods, 2001 and 2006. The former group enrolled the general population (GP), the latter group Afro-descendant (AD) subjects. The minimum inhibitory concentrations of clarithromycin, amoxicillin, tetracycline, metronidazole, and levofloxacin were determined using the E-test technique. Amplification was achieved through PCR and nucleic acid sequencing to detect mutations in the site of action of clarithromycin in the rRNA gene 23S. No amoxicillin or tetracycline-resistant strains were found. Clarithromycin resistance was found in 12% of the patients overall: 19.4% resistance in AD patients and no resistance in the GP group. This difference was statistically significant. The highest resistance was seen with metronidazole (36%), present in similar proportions in the two groups: 36.8% (GP) and 35.5% (AD). One GP patient and one AD patient had levofloxacin-resistant strains. Sequencing analysis of gene 23S rRNA showed that only mutation in position 2143 was presented in all clarithromycin-resistant strains.

Adaptation of salivary Lactobacillus strains to xylitol.

OBJECTIVE: Acid production from sugars is one of the virulence factors of cariogenic bacteria. To eliminate this factor, many authors have suggested using sugar substitutes like xylitol, which is not fermented by most oral bacteria. The aim of this work was to investigate whether oral strains of lactobacilli unable to utilise xylitol could become able to utilise this polyol. DESIGN: Twenty-eight oral strains and six ATCC strains of lactobacilli were tested. None was initially able to produce acids from xylitol. Media containing only xylitol was used in order to see if an adaptation was possible. The acid production from xylitol was measured by recording the pH variations of the culture medium. The acids produced were identified by HPLC. RESULTS: After a 15-days culture, 10 strains produced acids. After a 40-days culture, 11 more strains produced acid. When acid production occurred, lactic, formic, acetic, propionic and butyric acids were the organic acids formed by all the strains. CONCLUSIONS: Adaptation of oral strains of lactobacilli to xylitol can occur in vitro.

[Human anisakiasis: 5 cases in northern France]. / Anisakiase humaine: 5 cas dans le nord de la France.

We report 5 cases of human anisakiasis revealed respectively by an acute intestinal obstruction due to multiple small bowel stenosis, an acute inflammatory ileitis simulating appendicitis, ulcer type epigastralgia, purulent peritonitis and a latent small bowel tumor. Diagnosis was established in 4 cases on microscopic analysis of bowel specimens (eosinophilic granulomas and/or parasitic fragments) and in 1 case at gastroscopy. Serodiagnosis was positive in 2 of 4 cases and the consumption undercooked fishes was found in 4. In small samples we estimated the infestation (1 to 50 parasites) by anisakis larvae of 3 fish species: 80 p. 100 for herrings, 63 p. 100 for mackerels and 100 p. 100 for whitings. This work emphasizes the role of anisakiasis as a source of digestive symptoms and intestinal eosinophilic granuloma.