Many highly effective agents are available for the treatment of bacterial community-acquired pneumonia (community-acquired pneumonia) and other community-acquire respiratory tract infections (RTIs). Currently marketed antibiotics for community-acquired pneumonia demonstrate similar efficacy rates in clinical trials, and these agents have generally achieved clinical symptom resolution in 85-95% of trial participants.
Antibiotics and Antibiotic Resistance
Antimicrobial resistance in Streptococcus pneumoniae and other community-acquired pneumonia pathogens has progressed at an alarming rate. Approximately one-third of pneumococci exhibit reduced susceptibility to penicillin (i.e., higher MICs) that also confers reduced susceptibility to other agents in the β-lactam class of antibiotics. Macrolide resistance levels range between 23% and 30% in the United States, and much higher levels are observed in some other markets. N.
Penicillins
The penicillins comprise several subgroups of agents with a wide range of bacterial coverage and efficacy. Each penicillin molecule contains a basic β-lactam structure fused to a five-membered ring. Because of their broad spectrum of activity and availability in oral form, the penicillins are commonly used in the treatment of community-acquired pneumonia and have become the drugs of choice in treating many common infections.
Cephalosporins
The cephalosporins contain a basic β-lactam structure fused to a six-membered ring. Drugs in this class differ widely in their spectrum of activity, susceptibility to β-lactamases produced by bacteria, and serum half-life. Cephalosporins are categorized into four generations, with each newer generation representing an improvement in the spectrum of bacterial coverage. The most important agents in this class are the second- and third-generation agents, which are commonly used in hospitalized patients in combination with a macrolide.
Ceftin
Learn here about Cefuroxime generation, dosage, uses, and other useful bits of information you should know about Cefuroxime 500mg and 250mg before taking the medication.
Ceftriaxone and Cefdinir
Ceftriaxone (Omnicef) 300mg has been available generically in Europe since 2002. In 2000, Cubist Pharmaceuticals announced that it had acquired the rights to oral ceftriaxone and was developing an alternate oral formulation.
Carbapenems – Penicillin Derivative
Carbapenems are penicillin derivatives that have good activity against gram-positive and gram-negative aerobic and anaerobic bacteria. They are highly resistant to β-lactamase and have a very favorable spectrum of activity.
Macrolides: Erythromycin, Clarithromycin
Macrolides are a class of drugs that inhibit bacterial protein synthesis. They demonstrate excellent activity against atypical organisms (Mycoplasma, Chlamydia, and Legionella species), but have variable activity against typical pathogens (S. pneumoniae and H. influenzae). Macrolides are indicated for use in mild-to-moderate community-acquired pneumonia and are typically used as first- and second-line agents for this indication.
Ketolides – New Class of Macrolide Derivatives
Ketolides are a new class of macrolide derivatives designed specifically to combat macrolide-resistant respiratory tract pathogens. The ketolides exhibit good activity against gram-positive and some gram-negative organisms and have excellent activity against drug-resistant S. pneumoniae, including macrolide-resistant strains. Spontaneous resistance to the available ketolide, telithromycin, is rare. Ketolides display excellent pharmacokinetics that allow once-daily dose administration and extensive tissue distribution relative to serum.
Fluoroquinolones: Levofloxacin, Moxifloxacin, Gatifloxacin
Earlier generations of fluoroquinolones (e.g., ofloxacin) had limited activity against some respiratory pathogens, such as S. pneumoniae. However, recent fluoroquinolone agents (so-called third-generation agents, or the “respiratory fluoroquinolones”) are active against a broad spectrum of gram-positive and gram-negative bacteria, including atypical organisms. Therefore, they are highly effective in RTIs.