OBJECTIVES: To study the influence of resistance phenotypes (based on sentinel antibiotics: penicillin and amoxicillin with/without clavulanate) on the cefuroxime versus cefditoren susceptibility of Streptococcus pneumoniae and Haemophilus influenzae recovered from children with acute otitis media. METHODS: Middle ear isolates (193 S. pneumoniae and 114 H. influenzae) received in the Spanish Reference Laboratory (Instituto de Salud Carlos III) were tested. Antimicrobial susceptibility to penicillin, amoxicillin with/without clavulanate, cefuroxime and cefditoren was determined by agar dilution using Mueller-Hinton agar supplemented with 5% sheep blood for S. pneumoniae and Haemophilus Test Medium for H. influenzae. Strains were classified according to penicillin susceptibility (S. pneumoniae) or beta-lactamase production (H. influenzae). RESULTS: The decrease in penicillin susceptibility of S. pneumoniae (from the susceptible to the resistant category) decreased amoxicillin and cefuroxime susceptibility rates from 100% to 34% and 0%, respectively. All pneumococcal strains were inhibited by 0.5 mg/L cefditoren, including those from penicillin-resistant serotypes 14, 23F, 6B and 9V with higher amoxicillin versus penicillin MICs. Susceptibility rates of beta-lactamase-positive H. influenzae strains were 93.8% and 85.4% to amoxicillin/clavulanate and cefuroxime, respectively. Resistance to amoxicillin/clavulanate (MIC>or=8/4 mg/L) was 12.1% (8 out of 66) and 6.3% (3 out of 48) in beta-lactamase-negative and -positive strains, respectively. All H. influenzae strains were inhibited by <or=0.06 mg/L cefditoren. CONCLUSIONS: Susceptibility to sentinel beta-lactams cannot predict activity of other members of the group. The addition of clavulanic acid to amoxicillin does not guarantee 100% coverage of H. influenzae, regardless of beta-lactamase production.
OBJECTIVES: To study the influence of resistance phenotypes (based on sentinel antibiotics: penicillin and amoxicillin with/without clavulanate) on the cefuroxime versus cefditoren susceptibility of Streptococcus pneumoniae and Haemophilus influenzae recovered from children with acute otitis media. METHODS: Middle ear isolates (193 S. pneumoniae and 114 H. influenzae) received in the Spanish Reference Laboratory (Instituto de Salud Carlos III) were tested. Antimicrobial susceptibility to penicillin, amoxicillin with/without clavulanate, cefuroxime and cefditoren was determined by agar dilution using Mueller-Hinton agar supplemented with 5% sheep blood for S. pneumoniae and Haemophilus Test Medium for H. influenzae. Strains were classified according to penicillin susceptibility (S. pneumoniae) or beta-lactamase production (H. influenzae). RESULTS: The decrease in penicillin susceptibility of S. pneumoniae (from the susceptible to the resistant category) decreased amoxicillin and cefuroxime susceptibility rates from 100% to 34% and 0%, respectively. All pneumococcal strains were inhibited by 0.5 mg/L cefditoren, including those from penicillin-resistant serotypes 14, 23F, 6B and 9V with higher amoxicillin versus penicillin MICs. Susceptibility rates of beta-lactamase-positive H. influenzae strains were 93.8% and 85.4% to amoxicillin/clavulanate and cefuroxime, respectively. Resistance to amoxicillin/clavulanate (MIC>or=8/4 mg/L) was 12.1% (8 out of 66) and 6.3% (3 out of 48) in beta-lactamase-negative and -positive strains, respectively. All H. influenzae strains were inhibited by <or=0.06 mg/L cefditoren. CONCLUSIONS: Susceptibility to sentinel beta-lactams cannot predict activity of other members of the group. The addition of clavulanic acid to amoxicillin does not guarantee 100% coverage of H. influenzae, regardless of beta-lactamase production.
Authors: M Torrico; L Aguilar; N González; M J Giménez; O Echeverría; F Cafini; D Sevillano; L Alou; P Coronel; J Prieto Journal: Antimicrob Agents Chemother Date: 2007-07-30 Impact factor: 5.191
Authors: H Hupková; I Urbancíková; K Bazárová; Z Szovenyová; V Fandáková; M Bukovský Journal: Folia Microbiol (Praha) Date: 2010-02-07 Impact factor: 2.099
Authors: Young Kyung Yoon; Chan Soon Park; Jae Wook Kim; Kyurin Hwang; Sei Young Lee; Tae Hoon Kim; Do Yang Park; Hyun Jun Kim; Dong Young Kim; Hyun Jong Lee; Hyun Young Shin; Yong Kyu You; Dong Ah Park; Shin Woo Kim Journal: Infect Chemother Date: 2017-12