Pneumonia

Chlamydia pneumoniae an obligate intracellular bacteria, has been established as an important cause of adult respiratory disease including pneumonia, bronchitis, sinusitis and pharyngitis. There is no animal reservoir. Incidence/Prevalence in USA: Estimated incidence of 100 to 200 cases of pneumonia/100,000/ year.

A chronic non-malignant lung disease caused by inhalation of asbestos, a hazardous dust found in a variety of work places. This disease persists in spite of substantial knowledge about its cause, and effective means of prevention. The disease typically occurs 10-15 years after initial exposure. Asbestosis is a fibrotic interstitial lung disease caused by a cascade of responses to inhaled asbestos fibers.

Usually self-limited febrile illnesses characterized by inflammation of conjunctivae and the respiratory tract. Adenovirus infections occur in epidemic and endemic situations. Incidence/Prevalence in USA: Very common infection, estimated at 2-5% of all respiratory infections. More common in infants and children.

TABLE: Emerging Therapies in Development for Community-Acquired Pneumonia, 2004 summarizes emerging antibacterial agents in late-stage development and their expected sales potential in the community-acquired pneumonia market.

Cefpodoxime proxetil is an esterified pro-drug of cefpodoxime created for oral formulation. It is stable in the presence of most β-lactamase enzymes, effectively extending its spectrum of activity against several gram-positive and gram-negative bacteria that are resistant to penicillins and other cephalosporins.

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.