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Background: The aim of this study was to assess the primary and combined resistances in pediatric Helicobacter pylori isolates to seven antimicrobial agents in 2000-2001. Materials and Methods: Resistance rates of pre-treatment isolates from 115 children were investigated using limited agar dilution method alone and with E-test. The cut-off concentrations for resistance were: > 8 mg/L metronidazole, > 1 mg/L clarithromycin and azithromycin, > 4 mg/L clindamycin, > 0.5 mg/L amoxicillin, > 4 mg/L tetracycline and > 1mg/L ciprofloxacin. Results: 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 was no significant age (1-9 vs. 10-18 years) and gender difference. Prevalence of both macrolide resistant and intermediately susceptible strains was 21.9% for azithromycin and 15.9% for clarithromycin. Of 18 metronidazole resistant isolates, 77.8% exhibited minimal inhibitory concentration (MIC) of metronidazole > 16 mg/L. Conclusions: 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 associated with the resistance prevalence 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. Multidrug resistance to newer macrolides, metronidazole and ciprofloxacin in association with a slightly elevated amoxicillin MIC (0.38 mg/L) was detected in one strain. [ABSTRACT FROM AUTHOR]

Risk factors for primary Helicobacter pylori resistance in 186 children with gastroduodenal diseases (44 from villages/small towns and 130 from large towns/cities) in 2000-2003 were tested. Susceptibility was tested by a limited agar dilution method. Overall resistance rates to metronidazole, clarithromycin, tetracycline and both metronidazole and clarithromycin were 14.5, 11.9, 3.3 and 4.3 %, respectively. No amoxycillin resistance was observed. Tetracycline resistance was found in six children aged 7-18 years. Clarithromycin resistance was more common in children from small towns/villages (22.7 %) than in those from large towns/cities (8.5 %, P < 0.05). There were no significant differences (P > 0.05) in resistance rates between children from northern Bulgaria and those from southern regions. Resistance rates in duodenal ulcer patients and other children were, respectively, 10.5 and 15 % (P > 0.20) for metronidazole and 10.5 and 12 % (P > 0.20) for clarithromycin. No combined resistance to metronidazole and clarithromycin was found in 22 children aged 1-7 years and in 34 children living in northern Bulgaria. There were no significant associations of resistance with sex and age group (1-7- versus 8-18-year-old children) for all antibacterial agents tested. In conclusion, primary H. pylori resistance was absent (for metronidazole + clarithromycin) or low (4.5 % for clarithromycin) in children aged 1-7 years. Place of residence was associated with clarithromycin resistance rates.

The aim of the study was to assess Campylobacter infections in 309 patients with acute enterocolitis, 272 patients with relapses of chronic enterocolitis, 70 patients with inflammatory bowel disease (involving Crohn's disease and ulcerative colitis) and 31 patients with other chronic intestinal illnesses. Isolation and identification were performed conventionally. Limited agar dilution method was used for susceptibility testing of the strains. Campylobacter species were isolated in patients with acute enterocolitis (7.8%), chronic enterocolitis (6.2%), Crohn's disease (6.2%), ulcerative colitis (3.7%), and irritable bowel syndrome (8.3%). Hippurate-positive Campylobacter jejuni isolates accounted for 62.2% of Campylobacter strains. One tetracycline resistant Campylobacter upsaliensis isolate was detected from a girl with acute enterocolitis. Resistance rates to erythromycin (31.1%) and clarithromycin (22.2%) were high, whereas those to amoxicillin/clavulanate (4.4%), ampicillin/sulbactam (13.3%), tetracycline (24.4%) and ciprofloxacin (22.2%) were relatively low. Resistance to erythromycin and either tetracycline or ciprofloxacin was detected in 8.9% and 6.7%. The involvement of Campylobacter infection in relapses of chronic intestinal disorders and the susceptibility patterns of the strains strongly emphasize the role of Campylobacter as a cause of infection in this group of patients.

The aim of the study was to evaluate the prevalence of Helicobacter pylori and Helicobacter heilmannii among 321 children. Gram staining, urease test and culture were performed. Of all patients, 52.6% were H. pylori positive and 0.3% were H. heilmannii positive. H. pylori infection was associated with chronic gastritis in 57.1%, with duodenal ulcer in 75% and with non-ulcer dyspepsia in 25.6%. This infection was more frequent in children aged 11-18 years than in younger patients. Rapid urease test, culture and direct Gram staining showed 42.3, 96.5 and 78.2% sensitivity and 93.2, 100 and 84.6% specificity, respectively. H. pylori was detected in 60.2% of fresh versus 52.8% of frozen specimens and in 64.8% in gastric biopsy versus 25% in gastric mucus specimens. H. pylori growth was detected after nine to 10 days in 6.2% and after 11 days in 1.2%. Culture exhibited the best accuracy of the three diagnostic methods. Frozen biopsy specimens gave reliable H. pylori detection unlike gastric mucus specimens. Eleven days of incubation for H. pylori is recommended. The study confirms an early acquisition of H. pylori infection in Bulgaria. The incidence of H. heilmannii infection in childhood is uncommon but clinically important.

Bee glue (propolis) possesses antimicrobial, anti-inflammatory, anaesthetic and immunostimulating activities. The aim of the study was to evaluate the inhibitory effect of Bulgarian propolis on Helicobacter pylori growth in vitro. Activity of 30% ethanolic extract of propolis (EEP) against 38 clinical isolates of H. pylori was evaluated by using the agar-well diffusion method. Ethanol was used as a control. In addition, the effect of propolis on the growth of 26 H. pylori and 18 Campylobacter strains was tested by the disc diffusion method. Mean diameters of H. pylori growth inhibition by the agar-well diffusion method, using 30, 60 or 90 microl EEP or 30 microl ethanol per well, were 17.8, 21.2, 28.2 and 8.5 mm, respectively. EEP was significantly more active than ethanol against H. pylori (P < 0.001). The results obtained by the disc diffusion method were similar. The use of moist propolis discs resulted in mean diameters of growth inhibition of 21.4 mm for H. pylori and 13.6 mm for Campylobacter spp. Dried propolis discs exhibited antibacterial effect against 73.1% of H. pylori isolates, with a considerable zone of growth inhibition (> or = 15 mm) in 36.4% of isolates. Using dried propolis discs resulted in mean diameters of growth inhibition of 12.4 mm for H. pylori and 11.6 mm for Campylobacter spp. In conclusion, Bulgarian propolis possesses considerable antibacterial activity against H. pylori, and can also inhibit the growth of Campylobacter jejuni and Campylobacter coli. The potential of propolis in the prevention or treatment of H. pylori infection is worth further extensive evaluation.

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 macrolide-resistant 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 > or = 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.

The aim of this study was to evaluate the primary and combined resistance of Helicobacter pylori against four antimicrobial agents by a screening agar method (SAM) and a modified disk diffusion method (MDDM) alone and in combination. Pre-treatment H. pylori isolates from 192 consecutive H. pylori-positive patients at three hospitals in Sofia were investigated. MDDM was performed with disks containing metronidazole (5 microg), clarithromycin (15 microg) or erythromycin (15 microg), ciprofloxacin (5 microg) and tetracycline (30 microg). Resistance was determined by an inhibitory zone of <16 mm for metronidazole and < or =30 mm for other agents tested. The cut-off concentrations used to define resistance by SAM were: metronidazole >8 mg/L, clarithromycin >2 mg/L, tetracycline >4 mg/L and ciprofloxacin >1 mg/L. Primary resistance rates in H. pylori were: metronidazole 28.6%, clarithromycin 9.7%, metronidazole + clarithromycin 2.8%, ciprofloxacin 3.9%, metronidazole + ciprofloxacin 2.3%, tetracycline 1.9% and metronidazole + tetracycline 1.2%. Among metronidazole-resistant isolates, combined resistance to clarithromycin, ciprofloxacin and tetracycline was present in 11.4% (5 of 44 strains), 8.3% (3 of 36) and 4.9% (2 of 41), respectively. Two strains exhibited triple resistance to macrolides, metronidazole and either ciprofloxacin or tetracycline. Three tetracycline-resistant strains were detected in 1999; however, resistance rates to other agents were relatively stable during the 6 years. Primary H. pylori resistance to metronidazole is moderate and resistance to clarithromycin and to ciprofloxacin is considerable in comparison with results in most other countries. The alarming appearance of strains harbouring combined resistance or multiresistance provides the motivation for continued surveillance of H. pylori at global, national and regional levels.