Antimicrobial resistance among respiratory pathogens in Spain: latest data and changes over 11 years (1996-1997 to 2006-2007).

A nationwide multicenter susceptibility surveillance study (Susceptibility to the Antimicrobials Used in the Community in España [SAUCE] project), SAUCE-4, including 2,559 Streptococcus pneumoniae, 2,287 Streptococcus pyogenes, and 2,736 Haemophilus influenzae isolates was carried out from May 2006 to June 2007 in 34 Spanish hospitals. Then, the results from SAUCE-4 were compared to those from all three previous SAUCE studies carried out in 1996-1997, 1998-1999, and 2001-2002 to assess the temporal trends in resistance and the phenotypes of resistance over the 11-year period. In SAUCE-4, on the basis of the CLSI breakpoints, penicillin (parenteral, nonmeningitis breakpoint) and cefotaxime were the antimicrobials that were the most active against S. pneumoniae (99.8% and 99.6%, respectively). Only 0.9% of isolates had a penicillin MIC of > or = 2 microg/ml. In S. pyogenes, nonsusceptibility to erythromycin was observed in 19.4% of isolates. Among the H. influenzae isolates, a beta-lactamase-positive prevalence of 15.7% was found. A statistically significant temporal decreasing trend over the 11-year period was observed for nonsusceptibility (from 60.0% to 22.9%) and resistance (from 36.5% to 0.9%) to penicillin and for the proportion of erythromycin-resistant isolates of S. pneumoniae of the macrolide-lincosamide-streptogramin B (MLS(B)) phenotype (from 98.4% to 81.3%). A similar trend was observed for the prevalence of ampicillin resistance (from 37.6% to 16.1%), beta-lactamase production (from 25.7% to 15.7%), and beta-lactamase-negative ampicillin resistance (BLNAR) in H. influenzae (from 13.5% to 0.7%). Among erythromycin-resistant isolates of S. pyogenes, a significant increasing trend in the prevalence of MLS(B) was observed (from 7.0% to 35.5%). SAUCE-4 confirms a generalized decline in the resistance of the main respiratory pathogens to the antimicrobials as well as a shift in their resistance phenotypes.

What are the most appropriate antibiotics for the treatment of acute exacerbation of chronic obstructive pulmonary disease? A therapeutic outcomes model.

OBJECTIVES: To predict the clinical efficacy of several antimicrobials in the treatment of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). METHODS: A probability model (therapeutic outcomes model) was used to predict the likelihood of clinical success with particular antimicrobial agents in the treatment of patients with AECOPD, both in those clinically diagnosed (total patients with an AECOPD diagnosis regardless of the cause) and in those with bacterial AECOPD. The model took into account the following variables: (i) the proportion of patients with a clinical diagnosis of AECOPD and non-bacterial disease; (ii) likelihood of spontaneous resolution of a non-bacterial infection; (iii) prevalence of subcauses (different bacterial species) in bacterial AECOPD; (iv) rates of spontaneous resolution of bacterial AECOPD; and (v) antimicrobial efficacy of each antibiotic against each bacterial species (susceptibility based on PK/PD breakpoints). RESULTS: Fluoroquinolones (levofloxacin, ciprofloxacin and moxifloxacin), a new third-generation oral cephalosporin (cefditoren) and high doses of amoxicillin/clavulanate were the antimicrobials with the highest predicted clinical efficacy both in mild-moderate AECOPD and in severe AECOPD (rates of 89.2% to 90.5% and 80.3% to 88.1%, respectively), whereas cefaclor, azithromycin, erythromycin and clarithromycin had the lowest predicted clinical efficacy (rates of 79.1% to 81.3% and 51.8% to 55.6% for mild-moderate and severe AECOPD, respectively), which was not much higher than that predicted for placebo (73.6% and 45.5%, respectively). CONCLUSIONS: According to our model, fluoroquinolones (levofloxacin, ciprofloxacin and moxifloxacin), cefditoren and amoxicillin/clavulanate are the most appropriate antibiotics for the treatment of patients with AECOPD in terms of predicted clinical efficacy, with wide differences with respect to other antibiotics commonly used in the treatment of these patients, such as clarithromycin and azithromycin.