Antimicrob Agents Chemother. 2000 Oct;44(10):2709-14.
Epidemiological survey of amoxicillin-clavulanate resistance and corresponding molecular mechanisms in Escherichia coli isolates in France: new genetic features of bla(TEM) genes.

Leflon-Guibout V, Speldooren V, Heym B, Nicolas-Chanoine M.

Microbiology Department, Hopital Ambroise-Pare, Universite Paris V, 92100 Boulogne-Billancourt, France.

Amoxicillin-clavulanate resistance (MIC >16 microg/ml) and the corresponding molecular mechanisms were prospectively studied in Escherichia coli over a 3-year period (1996 to 1998) in 14 French hospitals. The overall frequency of resistant E. coli isolates remained stable at about 5% over this period. The highest frequency of resistant isolates (10 to 15%) was observed, independently of the year, among E. coli isolated from lower respiratory tract samples, and the isolation rate of resistant strains was significantly higher in surgical wards than in medical wards in 1998 (7.8 versus 2.8%). The two most frequent mechanisms of resistance for the 3 years were the hyperproduction of the chromosomal class C beta-lactamase (48, 38.4, and 39.7%) and the production of inhibitor-resistant TEM (IRT) enzymes (30.4, 37.2, and 41.2%). By using the single-strand conformational polymorphism-PCR technique and sequencing methods, we determined that 59 IRT enzymes corresponded to previously described IRT enzymes whereas 8 were new. Three of these new enzymes derived from TEM-1 by only one amino acid substitution (Ser130Gly, Arg244Gly, and Asn276Asp), whereas three others derived by two amino acid substitutions (Met69Leu and Arg244Ser, Met69Leu and Ile127Val, and Met69Val and Arg275Gln). The two remaining new IRTs showed three amino acid substitutions (Met69Val, Trp165Arg, and Asn276Asp and Met69Ile, Trp165Cys, and Arg275Gln). New genetic features were also found in bla(TEM) genes, namely, bla(TEM-1B) with either the promoters Pa and Pb, P4, or a promoter displaying a C-->G transversion at position 3 of the -35 consensus sequence and new bla(TEM) genes, notably one encoding TEM-1 but possessing the silent mutations originally described in bla(TEM-2) and then in some bla(TEM)-encoding IRT enzymes.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10991849&dopt=Abstract antibiotic amoxicillin




J Pediatr Gastroenterol Nutr. 2000 Oct;31(4):424-7.
Helicobacter pylori infection in recurrent abdominal pain.

Frank F, Stricker T, Stallmach T, Braegger CP.

Department of Pediatric Gastroenterology and Nutrition, University Children's Hospital, Zurich, Switzerland.

BACKGROUND: Helicobacter pylori is associated with chronic gastritis and peptic ulcer in adults and in children. The purpose of the present study was to analyze the association of recurrent abdominal pain and H. pylori infection in children and to evaluate the efficacy of antimicrobial treatment in patients with evidence of infection. METHODS: The clinical and histopathologic findings in children who underwent diagnostic upper endoscopy for recurrent abdominal pain were analyzed retrospectively. Patients with evidence of infection with H. pylori were treated with a combination of omeprazole, amoxicillin, and clarithromycin. Efficacy of treatment was assessed using the 13C-urea-breath test. RESULTS: H. pylori was found in histopathologic sections of 29 (40%) of 73 patients undergoing diagnostic endoscopy for recurrent abdominal pain. Five children (17%) were of Swiss ethnic origin, and 24 (83%) were non-Swiss. All the infected patients had chronic gastritis and 4 (14%) had ulcerations in the duodenum. Treatment with omeprazole, amoxicillin, and clarithromycin resulted in eradication of the infection in all and in resolution of the clinical symptoms in 15 (80%) of 19 patients who had a follow-up examination. CONCLUSIONS: The presented data suggest that gastritis induced by H. pylori may be associated with recurrent abdominal pain and that in Switzerland infections with H. pylori primarily involve persons who are non-Swiss. A combined therapy results in eradication of the bacterium and in improvement of the clinical symptoms in a significant majority of the patients.

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Rev Latinoam Microbiol. 1998 Jul-Dec;40(3-4):128-34.
Effect of beta-lactamase inhibitors on minimum inhibitory concentration of ampicillin and amoxicillin for Staphylococcus aureus strains.

Paniagua GL, Monroy E, Garcia O, Vaca S.

Escuela Nacional de Estudios Profesionales Iztacala, UNAM, Mexico.

Seventy strains of Staphylococcus aureus isolated from the nasopharynx (80%), urinary tract (16%), skin (1 strain) and eyes (2 strains) of patients at the clinical laboratory "El eritrocito" were analyzed. Susceptibility to 12 antibiotics was tested by the method of Kirby-Bauer. Minimal inhibitory concentration (MIC) of ampicillin, ampicillin + sulbactam, amoxicillin and amoxicillin + clavulanic acid were determined by plate dilution. Percentages of resistance were: Penicillin and ampicillin (100%), ceftazidime (81.4%), erythromycin (68.6%), tetracycline (31.4%) trimethoprim-sulphametoxasol (25.7%), dicloxacillin and pefloxacin (12.8%), cefuroxime and cefotaxime (4.3%), gentamicin (2.8%), cephalothin (0%). All strains were resistant to three or more antibiotics, with higher percentages of resistance to four (31.4%), three (27.1%), five (21.4%) and six (12.9%) drugs. One strain was resistant to nine antibiotics and 5.9% were resistant to seven. 97.5% of the strains were beta-lactamase-positive. The MIC50 of ampicillin and amoxicillin was 500 micrograms/ml and the MIC90 were 1727 micrograms/ml and 2000 micrograms/ml, respectively. beta-lactamase inhibitors sulbactam and clavulanic acid reduced these values eightfold, except for the MIC50 of ampicillin + sulbactam whose reduction was sixteen fold. These results show that the combination of beta-lactamic + beta-lactamase inhibitor was more efficient than cephalosporins for killing these beta-lactamase-positive strains.

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auckland.ac.nz

AIM: To assess General Practice (GP) description and management of upper respiratory tract infections (URTI), including conditions under which they prescribe antibiotics. METHOD: A telephone survey of a randomised sample of Auckland GPs. RESULTS: There was a 61% response rate. 82 of the 100 GPs interviewed agreed that most patients presenting with URTI expected antibiotics. Persistent symptoms and indication of specific infection (tonsillitis, otitis media, sinusitis, pharyngitis, purulent sputum) were common reasons for prescribing. Patients travelling overseas, expecting or requesting antibiotics and prior use of over-the-counter (OTC) medications increased antibiotic prescribing-rates. Most GPs (95%) issued as-needed prescriptions on occasion; 13% did this often. Amoxicillin and amoxicillin/clavulanic acid were most commonly used. Despite wide-ranging antibiotic use for URTI (0 to 90%), only 6% of GPs felt they prescribed more antibiotics than others. CONCLUSIONS: The results suggest over-prescription is common-place, but use of as-needed prescriptions to reduce antibiotic use is encouraging. Exploration of patient expectations in the consultation may assist in decreasing prescribing rates.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11198542&dopt=Abstract antibiotic amoxicillin