Eur J Clin Microbiol Infect Dis. 2005 Apr;24(4):276-9.
In vitro activity of fosfomycin alone and in combination with amoxicillin, clarithromycin and metronidazole against Helicobacter pylori compared with combined clarithromycin and metronidazole.

Blacky A, Makristathis A, Apfalter P, Willinger B, Rotter ML, Hirschl AM.

Department of Hygiene and Medical Microbiology, Division of Hospital Hygiene, Medical University Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.

In order to evaluate the suitability of fosfomycin in combination with other agents for the treatment of Helicobacter pylori infections, the susceptibility profiles of 65 H. pylori strains were determined against multiple antimicrobial agents and combinations thereof using the agar dilution method. For fosfomycin alone, the range of minimum inhibitory concentration (MIC) results and the MICs at which 50% and 90% of strains were inhibited were 0.5-32 mug/ml and 2 and 4 mug/ml, respectively. For the combination of fosfomycin with amoxicillin, clarithromycin or metronidazole, the means calculated for the minimum and maximum fractional inhibitory concentration index were 0.70-1.17 and 1.15-2.03, respectively, suggesting partial synergy or indifference in the majority of strains. The combination of clarithromycin and metronidazole showed synergistic activity against 14 of 28 H. pylori strains tested. The in vitro activity results suggest the combination of fosfomycin with either amoxicillin or clarithromycin may be a promising alternative for the treatment of H. pylori infection. However, the clinical efficacy of these regimens remains to be investigated.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15902535&dopt=Abstract antibiotic amoxicillin




uic.edu

The in vitro activity of ABT-773, a new ketolide, was compared with those of clarithromycin, amoxicillin, metronidazole, and tetracycline against 15 strains of Helicobacter pylori. The MIC of ABT-773 at which 90% of isolates were inhibited was 0.25 microg/ml, which was 3 dilutions higher than that of the most active agent, clarithromycin. Synergy and antagonism were not seen with any combinations. Additive activity was seen with tetracycline, metronidazole, and amoxicillin in 100, 60, and 40% of the combinations, respectively.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10952605&dopt=Abstract antibiotic amoxicillin

chu-bordeaux.fr

Increased resistance to clarithomycin and metronidazole, the two main antibiotics used to treat Helicobacter pylori infection, has led to a search for alternatives to the proton pump inhibitor based triple therapies commonly used. The main rescuse therapy is a bismuth-based quadruple therapy. However, triple therapies with tetracycline and metronidazole or amoxicillin and metronidazole can be considered in the case of clarithomycin resistance. They can also be used in the case of metronidazole resistance by increasing the dose and duration of metronidazole. The only therapy without clarithomycin and metronidazole includes rifabutin and amoxicillin. Dual therapies with amoxicillin and a proton pump inhibitor at high dose can also be used.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11118869&dopt=Abstract antibiotic amoxicillin




J Vet Pharmacol Ther. 2000 Aug;23(4):223-8.
Amoxicillin pharmacokinetics in harbor seals (Phoca vitulina) and northern elephant seals (Mirounga angustirostris) following single dose intravenous administration: implications for interspecific dose scaling.

Gulland FM, Stoskopf MK, Johnson SP, Riviere J, Papich MG.

The Marine Mammal Center, Marin Headlands, GGNRA, Sausalito, CA 94965, USA.

The pharmacokinetics of sodium amoxicillin after a single intravenous dose of 20 mg/kg were determined in ten harbor seals (Phoca vitulina) and ten northern elephant seals (Mirounga angustirostris). The seals ranged in age from 1 to 6 months and the mean weights were 11.7 kg (range, 9.5-18.5 kg) for harbor seals and 47.1 kg (range, 39.5-61.4 kg) for elephant seals. The median half-life of amoxicillin (quartiles) in harbor seals, 1.5 (1.0-3.1) h. was not statistically different from that of elephant seals, 2.0 (1.4-3.8) h, nor were the differences between the terminal elimination rate constants between the two species. The only statistically significant differences between species were for area-under-the-curve (AUC), and total systemic clearance. The lack of statistical significance for differences in the volume of distribution at steady-state (Vss) may have been due to minor differences in the time frame of data collection and dose administered between the two groups. A true physiologic difference in drug handling, possibly related to renal perfusion or tubal secretory efficiency could affect amoxicillin kinetics in these species, and longer administration intervals may be appropriate for elephant seals as compared to harbor seals when administering multiple dose amoxicillin therapy at 20 mg/kg.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11126323&dopt=Abstract antibiotic amoxicillin




J Clin Microbiol. 2001 Jan;39(1):394-7.
High levels of resistance to metronidazole and clarithromycin in Helicobacter pylori strains in children.

Kalach N, Bergeret M, Benhamou PH, Dupont C, Raymond J.

Department of Pediatrics, Division of Pediatric Gastroenterology & Nutrition, Hopital Saint Vincent de Paul, Universite Paris V-Rene Descartes, 75674 Paris Cedex 14, France.

The aim of the study was to evaluate the prevalence of resistance to amoxicillin, metronidazole, and clarithromycin before treatment of Helicobacter pylori infection in children and to assess the evolution of resistance with time. The study was carried out between 1994 and 1999 with 150 H. pylori-positive children through gastric culture (antimicrobial susceptibility) and histology. All cultured H. pylori strains were sensitive to amoxicillin, 64 (43%) were resistant to metronidazole, 32 (21%) were resistant to clarithromycin, and 14 (9%) were resistant to both metronidazole and clarithromycin. The overall prevalence of resistance to metronidazole and clarithromycin did not change significantly with time. The study highlights the generalized high-level and stable metronidazole and clarithromycin resistance of H. pylori strains from children.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11136811&dopt=Abstract antibiotic amoxicillin