Prevalence of resistant Helicobacter pylori isolates in Bulgarian children

Abstract

The aim of this study was to assess the primary and combined resistances of Helicobacter pylori isolates obtained from paediatric patients in 2000-2001 to seven antimicrobial agents. Resistance rates of pre-treatment isolates from 115 children were investigated by the limited agar dilution method alone and by the E-test. The cut-off concentrations for resistance were: metronidazole >8 mg/L, clarithromycin and azithromycin >1 mg/L, clindamycin >4 mg/L, amoxicillin >0.5 mg/L, tetracycline >4 mg/L and ciprofloxacin >1 mg/L. Primary resistance rates were: metronidazole 15.8%, clarithromycin 12.4%, azithromycin 14.6%, clindamycin 20.0%, amoxicillin 0%, metronidazole + clarithromycin 4.5%, ciprofloxacin 6.0%, metronidazole + clarithromycin + ciprofloxacin 1.2%, tetracycline 3.1% and metronidazole + ciprofloxacin 1.2%. There were no significant age (1-9 years versus 10-18 years) or gender differences. Prevalence of both macrolideresistant and intermediately susceptible strains was 21.9% for azithromycin and 15.9% for clarithromycin. Of 18 metronidazole-resistant isolates, 77.8% exhibited a metronidazole MIC >32 mg/L. H. pylori resistance rates to metronidazole, clarithromycin and both agents were relatively low in Bulgarian children. However, resistance was found to all drugs tested except for amoxicillin. The consumption of newer macrolides and tetracyclines could be related to the prevalence of resistance to the corresponding agents. There were no significant differences in primary resistance rates of H. pylori to antimicrobial agents between children and adults except for metronidazole. Multi-drug resistance to newer macrolides, metronidazole and ciprofloxacin in association with a slightly elevated amoxicillin MIC (0.38 mg/L) was detected in one strain.

Analysis of antimicrobial susceptibility and virulence factors in Helicobacter pyloriclinical isolates

“…We were unable to detect an association between outcome and bacterial resistance, as previously reported [35,36]. With regard to virulence factors, no association was found when the MIC values for metronidazole, amoxicillin, clarithromycin, tetracycline, and furazolidone were compared with the different vac A, ice A, cag A and cag E genotypes, as described by several authors [35,37].…”

Inhibition of Helicobacter pylori‐induced Nuclear Factor‐kappa B Activation and Interleukin‐8 Gene Expression by Ecabet Sodium in Gastric Epithelial Cells

“…Nonselective medium plates were used as a control for strain viability [27,28]. The plates were incubated microaerophilically at 37°C for 3 days.…”

“…The plates were incubated microaerophilically at 37°C for 3 days. Nonselective medium plates were used as a control for strain viability [27,28].…”

Floating modular drug delivery systems with buoyancy independent of release mechanisms to sustain amoxicillin and clarithromycin intra-gastric concentrations

“…In order to estimate the maintenance of clarithromycin concentration in the stomach above the MIC of Helicobacter (2 mg/ mL) 33,34 , the release rates of clarithromycin assembled systems made of three (300 mg) and five modules (500 mg) (Figure 3) were used for predicting intra-gastric concentrations by the STELLA software 35 .…”