Author: Brian Holtry

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.

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.

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.

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.

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 (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 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.

Azithromycin (Zithromax) acts by binding to the 50S ribosomal subunit of susceptible microorganisms and interfering with microbial protein synthesis. It demonstrates activity in vitro against a wide range of bacteria, including gram-positive bacteria such as S. aureus, S. pneumoniae, and other streptococci, and gram-negative bacteria such as H. influenzae and H. parainfluenzae.

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.