Biomedical subjects
R Amores
Publications and source records attributed to R Amores.
Activity of oral antibiotics against respiratory tract pathogens in Spain.
The aim of this study was to carry out a nationwide survey to assess the susceptibility of clinical isolates of four respiratory pathogens against nine antibiotics. Eight Spanish centers participated in the study, collecting a total of 977 isolates of Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae and Moraxella catarrhalis. The susceptibility of S. pneumoniae to penicillin was 37.46% susceptible, 30.43% intermediate and 32.11% resistant. MIC(90) of all antibiotics against this microorganism were 48 mg/l, except cefaclor, cefixime and azithromycin. For S. pyogenes, all the strains were susceptible to penicillins and cephalosporins, and azithromycin was the least active with a rate of resistance of 11.43%. A total of 95 isolates of H. influenzae were betalactamase positive (26.32%). With regard to M. catarrhalis, only penicillin and amoxicillin showed MICs(90) >=8 mg/l.
[Activity of different antimicrobial agents against penicillin-resistant Streptococcus pneumoniae].
Since the first strains of penicillin-resistant Streptococcus pneumoniae were isolated in the 1960s, the rate of resistance has increased world- wide, though with geographic variations. Currently, the prevalence and patterns of antibiotic resistance in this microorganism vary widely from one country to another, as well as within in the same country. In our study we evaluated the in vitro susceptibility of 299 isolates of S. pneumoniae from patients with community-acquired respiratory tract infections from 1998-2000 to different antimicrobial agents. The following resistance results were obtained: 32.11% to penicillin, 4.35% to amoxicillin, 3.68% to amoxicillin-clavulanic acid, 69.9% to cefaclor, 32.44% to cefpodoxime, 34.11% to cefuroxime, and 24.41% to azithromycin. For cefixime and ceftibuten there are no NCCLS breakpoint criteria.
[Pharmacodynamic basis for the use of amoxicillin-clavulanic acid in respiratory infections due to Streptococcus pneumoniae: In vitro studies in an experimental model].
Amoxicillin-clavulanic acid is a first choice treatment for respiratory tract infections caused by Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. In a previous study we observed its high efficacy against penicillin-susceptible and intermediate-resistant strains of S. pneumoniae. We aimed to study the efficacy of this antibiotic against three strains of S. pneumoniae (susceptible, intermediate and resistant to penicillin) in a mouse model of pneumonia, and to determine the influence of the time of starting treatment and the in vitro postantibiotic effect. We also determined the serum levels of the antimicrobial agent in the mice, and correlated the pharmacodynamic parameters (Cmax/MIC, AUC/MIC and T>MIC) with the survival rate to establish the best predictor of efficacy. MICs with amoxicillin-clavulanic acid were 0. 03 mg/l, 0.25 mg/l and 2 mg/l for the penicillin-susceptible, -intermediate and -resistant strains, respectively. The ED90 were approximately 5 mg/kg for susceptible strains, 25 mg/kg for the intermediate and 50 mg/kg for the resistant strains. We observed a lower survival rate (approximately 55%) when the treatment began 31 h after infection than when it began 5 h (100%) and 19 h (approximately 90-100%) afterwards. Serum levels were dose dependent and the correlation with the pharmacodynamic parameters showed a significant association between survival and the T>MIC (r = 0.946). In vitro postantibiotic effects with 1, 4 and 10 times the MIC were 0.96 to 1.69 h for susceptible strains, 0.38 to 1.23 h for intermediate, and 1.52 to 2. 20 h for resistant strains. These results show the high efficacy of this antibiotic combination against strains with variable susceptibility to penicillin, with this activity being related mainly to the T>MIC of the microorganism. The postantibiotic effect would prolong the effect of the antibiotic in the dosing interval. These parameters and antimicrobial effects are important in terms of the clinical application of this antimicrobial agent.
Massive intraperitoneal hemorrhage from ruptured corpus luteum during anticoagulant therapy.
The unpredictability of hemorrhagic complications during anticoagulant therapy is well known. An unusual case of massive intraperitoneal hemorrhage from a ruptured corpus luteum during such therapy is presented. That this complication is uncommon may be because relatively few premenopausal women are placed on anticoagulant therapy. In addition, the most likely condition for which premenopausal women are given anticoagulants is thrombophlebitis associated with pregnancy and childbirth when ovulation is inhibited.