Medical Health Encyclopedia

Gram-Positive Pneumonia. S. aureus is common in hospital-acquired pneumonia and is a potentially life-threatening infection. Resistance to penicillin is the rule in these cases but certain specialized penicillins such as nafcillin are often still effective. The alternatives to penicillins are first- or second generation cephalosporins. Unfortunately, resistance to these agents is increasing as well. Vancomycin is used for highly resistant bacteria.

Gram-Negative Pneumonia. Patients with hospital-acquired pneumonia are at high risk for infection from gram-negative organisms. Such organisms include Pseudomonas aeruginosa and Klebsiella pneumonia, which require aggressive specific therapy. Powerful antibiotics used against these organisms include the fourth-generation cephalosporins, carbapenems, or ciprofloxacin alone or in combination with an aminoglycides (entamicin or tobramycin). Multidrug therapy may be necessary, particularly for patients, such as those who are on mechanical ventilators, who are at very high risk for multiple dangerous organisms.

Antibiotics for P. Carinii Pneumonia (Common in HIV-Positive Patients)

Trimethoprim-sulfamethoxazole is the antibiotic combination that is the first choice for both preventing and treating P carinii pneumonia in HIV-positive patients. Clindamycin-primaquine may be a good salvage treatment for patients who do not respond to standard therapies.

Side Effects of Antibiotics

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Most antibiotics have the following side effects (although specific antibiotics may have other side effects or fewer of the standard ones).

• The most common side effect for nearly all antibiotics is stomach problems.
• Antibiotics raise the risk for vaginal infections. Taking supplements of acidophilus or eating yogurt with active cultures may help restore healthy bacteria that offset the risk for such infections in women.
• Allergic reactions can also occur with all antibiotics but are most common with medications derived from penicillin or sulfa. These reactions can range from mild skin rashes to rare but severe, even life-threatening anaphylactic shock.
• Certain drugs, including some over-the-counter medications, interact with antibiotics; patients should inform the physician of all medications they are taking and of any drug allergies.