Principles of Antimicrobial Therapy

The choice of the antimicrobial used for the treatment of an infection is influenced by several factor: the age of the patient, the site of infection, immune status of the patient, efficacy of the drug, the profile of adverse effects, the prevalence of anti-microbial resistance and the concomitant presence of other systemic diseases or organ dysfunction.
The cephalosporins include three generations of agents. The second generation extends the antimicrobial spectrum of the first generation to include wide range of gram negative rods and Pseudomonas.
The -lactams act by inhibiting the incorporation of peptidoglycon into the bacterial cell wall. Penicilin G still remains the drug of choice for syphilis, meningococci, clostridia and pneumococcous. Ampicillin has an extended spectrum of activity aganst gram negative rods(Salmonella, Hemophilus influenzae). Penicillinase-resistant penicilins are the drugs of choice for infections due to -lactamase producing staphylococci. Piperacillin and ticarcillin are antipseudomonal penicillins.