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.

Cost of Azithromycin 250/500mg Tablets (Zithromax) Without Insurance

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 – 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.

Gatifloxacin (Gatiflo, Tequin and Zymar)

Gatifloxacin has a broad spectrum of activity similar to activity observed in other third-generation fiuoroquinolones. The agent is well absorbed following oral administration (almost 100% bioavailability), and its pharmacodynamic and pharmacokinetic properties (e.g., high volume of distribution, long elimination half-life) allow once-daily administration.


Aminoglycosides are the preferred agents for treating serious infections caused by aerobic gram-negative bacilli. Aminoglycosides play only a minor role in the treatment of community-acquired pneumonia; their use is typically limited to hospitalized patients with severe or complicated community-acquired pneumonia in which gram-negative infections (particularly P. aeruginosa) are suspected.

Glycopeptides – Bactericidal Antibiotics

Glycopeptides are bactericidal antibiotics used principally for treatment of severe gram-positive infections in patients who cannot receive or who have failed to respond to penicillins and cephalosporins. They may also be used in patients suspected of having pathogens resistant to β-lactams and other anti-infectives.


Oxazolidinones are bacteriostatic against staphylococci and enterococci and may be slowly bactericidal against other gram-positive bacteria.

Community-Acquired Pneumonia: Pathophysiology

Host defenses such as anatomic, functional, and mechanical barriers serve to protect the intact bronchial tree from invading organisms. Some key factors in the pathophysiology of community-acquired pneumonia are alterations in host defense mechanisms, invasion by virulent microorganisms, and the quantity (i.e., inoculum) of the invading microbes. community-acquired pneumonia is usually acquired by inhalation or aspiration of pulmonary pathogenic organisms into a lung segment or lobe. Much less commonly, community-acquired pneumonia may result from a secondary bacteremia from a distant source — for example, community-acquired pneumonia secondary to Escherichia coli urinary tract infection and/or bacteremia.

Pneumonia Risk Factors

Several risk factors are associated with increasing susceptibility to pneumonia. Smoking increases the risk of acquiring pneumonia by destroying both the ciliated cells and alveoli.