Publications (7)15.04 Total impact
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Article: Antibacterial resistance in Helicobacter pylori strains isolated from Bulgarian children and adult patients over 9 years.
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ABSTRACT: The aim of this study was to evaluate the primary, combined and post-treatment antibacterial resistance rates in 1205 Helicobacter pylori strains from non-treated (786 adults, 282 children) and treated (109 adults, 28 children) patients in Bulgaria. Susceptibility was tested by the limited agar dilution method. Overall primary resistance rates to metronidazole, clarithromycin, amoxicillin, tetracycline and both metronidazole and clarithromycin were respectively 15.0, 12.5, 1.5, 3.4 and 4.7% in children and 25.6, 12.6, 0.8, 5.2 and 4.9% in adults. Primary metronidazole resistance in adults was more common than in children, but the differences for other agents tested were not significant. Primary resistance rates were in the range of those reported worldwide. There was no significant increase in primary resistance rates from 1996/1999 to 2003/2004; however, clarithromycin resistance rates exhibited a slight tendency to increase. Post-treatment resistance to amoxicillin was detected in 1.6% of 63 strains. Post-treatment resistance to metronidazole was common (81.6%) and that to clarithromycin was considerable (36%). Alarming emergence of strains with triple resistance to amoxicillin, metronidazole and clarithromycin was found in two non-treated and three treated patients. The results motivate a larger and continuing surveillance of H. pylori resistance in Bulgaria and worldwide.Journal of Medical Microbiology 02/2006; 55(Pt 1):65-8. · 2.50 Impact Factor -
Article: Activity of Bulgarian propolis against 94 Helicobacter pylori strains in vitro by agar-well diffusion, agar dilution and disc diffusion methods.
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ABSTRACT: Propolis exhibits antimicrobial, anti-inflammatory and other biological effects. The aim of this study was to evaluate the activity of 30 % ethanolic extract of Bulgarian propolis against 94 Helicobacter pylori strains by three methods. By the agar-well diffusion method, only 13.8 % of the strains exhibited no inhibition by 30 microl propolis extract (containing 9 mg propolis) and all isolates were inhibited to some extent by 90 microl of the extract (27 mg propolis) per well. The mean diameters of growth inhibition by 30, 60 or 90 microl propolis extract or 30 microl 96 % ethanol per well were 16.8, 19.2, 27.5 and 8.3 mm, respectively. The propolis extract was more active than the ethanol (P < 0.001). With 90 microl propolis extract per well, 69.4 % of the strains exhibited large diameters of growth inhibition (> or =20 mm) versus 26.6 % with 30 mul per well (P < 0.001). With moist propolis discs, inhibition was detected in more strains (92.1 %) than with dried discs (78.2 %, P < 0.05), with mean inhibitory diameters of 18.7 and 13.8 mm, respectively. By the agar dilution method, 100 and 300 microg propolis ml(-1) inhibited the growth of 57.1 % and 76.2 %, respectively, of the 21 strains tested. In conclusion, Bulgarian propolis had a strong and dose-dependent activity against most of the H. pylori strains tested. Although the effect of propolis on H. pylori in vitro is promising, further microbiological, pharmacological and clinical trials are required.Journal of Medical Microbiology 05/2005; 54(Pt 5):481-3. · 2.50 Impact Factor -
Article: Campylobacter infection in 682 bulgarian patients with acute enterocolitis, inflammatory bowel disease, and other chronic intestinal diseases.
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ABSTRACT: 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.Diagnostic Microbiology and Infectious Disease 06/2004; 49(1):71-4. · 2.53 Impact Factor -
Article: Helicobacter pylori infection in elderly Bulgarian patients.
Journal of Medical Microbiology 01/2004; 52(Pt 12):1131-3. · 2.50 Impact Factor -
Article: Inhibition of Helicobacter pylori growth in vitro by Bulgarian propolis: preliminary report.
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ABSTRACT: 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.Journal of Medical Microbiology 05/2003; 52(Pt 5):417-9. · 2.50 Impact Factor -
Article: Prevalence of resistant Helicobacter pylori isolates in Bulgarian children.
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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 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.Journal of Medical Microbiology 10/2002; 51(9):786-90. · 2.50 Impact Factor -
Article: Characteristics and trends in macrolide resistance among Helicobacter pylori strains isolated in Bulgaria over four years
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ABSTRACT: Macrolide resistance trends were examined among Helicobacter pylori strains from 154 patients between 1994 and 1998. Applicabilities of screening agar method (SAM) and modified disk diffusion method (MDDM) were evaluated. Overall primary resistance rates to erythromycin and clarithromycin were 14.8% and 8.7%, respectively. No association was found with age, sex, and diseases. Clarithromycin-resistance rate reached 12.5% in the last 2 years. Secondary resistance to erythromycin occurred more often (in 62.5%) than to clarithromycin (in 42.9%). Therapy with spiramycin or erythromycin in four cases induced no clarithromycin resistance. These data show a considerable prevalence of H. pylori resistance to macrolides, which exhibited a tendency to increase and was often associated with metronidazole resistance. By comparing the MDDM with SAM, an overall agreement was obtained in 81 (94.2%) of 86 results. MDDM and SAM are reliable techniques for testing H. pylori susceptibility to macrolides.Diagnostic Microbiology and Infectious Disease.
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Institutions
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2002–2006
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Medical University of Sofia
- Department of Microbiology
Sofia, Oblast Sofiya-Grad, Bulgaria
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