The choice of empiric antibiotic regimens for the treatment of community-acquired pneumonia (CAP), from an expanding list of drug categories and specific antibiotics, is based on the likelihood of a specific pathogen, severity of illness, and known community susceptibilities, as well as safety.
Specific recommendations for the treatment of patients with CAP are presented separately.
A review of the literature that compared the empiric use of fluoroquinolone monotherapy with the combination of a beta-lactam and a macrolide concluded that neither one of the regimens has been proven to be superior to the other.
The fluoroquinolones are known to cause prolongation of the QT interval. Moxifloxacin and levofloxacin have both been associated with ventricular arrhythmias and have comparable cardiac safety profiles in older adult patients requiring hospitalization for treatment of CAP. Clinical outcomes have been comparable with respect to cure rates, but moxifloxacin has been associated with a faster time to becoming afebrile.
Macrolides are effective as monotherapy in outpatients with pneumonia. However, most patients had mild infections, and these studies were performed at a time when the prevalence of macrolide-resistant Streptococcus pneumoniae was lower than it is currently. Like the fluoroquinolones, the macrolides have also been associated with prolongation of the QT interval. They have also been associated with a small increased risk of cardiovascular death.
Combination therapy with a macrolide plus a third-generation cephalosporin, compared with a cephalosporin alone, decreased mortality and/or hospital stay for patients with CAP requiring hospitalization. Similar findings have been observed for combination therapy of a beta-lactam and a macrolide compared with a beta-lactam alone in S. pneumoniae bacteremia and severe CAP.
The optimal duration of antibiotic therapy for CAP is unknown. Studies suggest that a minimum of five days of therapy using respiratory fluoroquinolones (shorter for some regimens of azithromycin) for uncomplicated CAP is associated with good outcomes.
Abstracts for Reference 105 of 'Antibiotic studies for the treatment of community-acquired pneumonia in adults'
No difference was found in the effectiveness and safety of short- versus long-course antimicrobial treatment of adult and paediatric patients with CAP of mild to moderate severity.
Short- versus long-course antibacterial therapy for community-acquired pneumonia : a meta-analysis. - PubMed - NCBI
キノロン vs βラクタム
Several large randomized treatment trials of CAP have compared fluoroquinolone therapy to treatment with beta-lactams with or without a macrolide．In a meta-analysis that included 23 randomized trials, respiratory fluoroquinolones (levofloxacin, moxifloxacin, or gemifloxacin) were more likely to result in treatment success than the combination of a beta-lactam plus a macrolide for the treatment of CAP that was mostly mild to moderate in severity (odds ratio [OR] 1.39, 95% CI 1.02-1.90)． However, fluoroquinolones were more effective only in open-labeled trials but not in randomized controlled trials. Both of the groups included agents with activity against atypical bacteria (fluoroquinolones or macrolides). A review of the literature that was published after the meta-analysis that compared the use of fluoroquinolone monotherapy with the combination of a beta-lactam and a macrolide concluded that neither one of the regimens has been proven to be superior to the other．
A multicenter, randomized study comparing the efficacy and safety of intravenous and/or oral levofloxacin versus ceftriaxone and/or cefuroxime axetil... - PubMed - NCBI
A comparative study of levofloxacin and ceftriaxone in the treatment of hospitalized patients with pneumonia. - PubMed - NCBI
Oral gemifloxacin versus sequential therapy with intravenous ceftriaxone/oral cefuroxime with or without a macrolide in the treatment of patients hos... - PubMed - NCBI
Randomized, double-blind, comparative study of grepafloxacin and amoxycillin in the treatment of patients with community-acquired pneumonia. - PubMed - NCBIOnce-daily sparfloxacin versus high-dosage amoxicillin in the treatment of community-acquired, suspected pneumococcal pneumonia in adults. Sparfloxac... - PubMed - NCBI
Trovafloxacin versus high-dose amoxicillin (1 g three times daily) in the treatment of community-acquired bacterial pneumonia. - PubMed - NCBI
The emergence of drug-resistant Streptococcus pneumoniae (DRSP) has made the empiric treatment of community-acquired pneumonia (CAP) more difficult．
Drug-resistant infection should be considered in communities where the prevalence of DRSP is known to be appreciable． In some regions of the world, including the United States, the prevalence of macrolide-resistant S. pneumoniae is now >25 percent.
Risk factors for drug-resistant S. pneumoniae in adults include．
●Age >65 years
●Beta-lactam, macrolide, or fluoroquinolone therapy within the past three to six months
●Immunosuppressive illness or therapy
●Exposure to a child in a daycare center
Recent therapy or a repeated course of therapy with beta-lactams, macrolides, or fluoroquinolones is a risk factor for pneumococcal resistance to the same class of antibiotic．