chapter 2

• • bacteriostatic drugs cause a reversible inhibition of grwoth
  • bactericidal drugs kills their target bacteria
• in patient with strong immune defenses, bacteriostatic and bactericidal drugs can be effective. for a patient that is immunocompromised, bactericidal must be used. regardless, life threatening infections like acute endocarditis require use of bactericidal drug
• spectrum of activity relates to diversity of targeted bacteria
• narrow spectrum means they only affect certain type of bacteria (gram positive or gram negative)
• if pathogen has been identified, it is best to use narrow spectrum am and minimize damage to microbiota
• broad spectrum targets wide variety, including both gram posi and nega. used as empiric therapy to cover wide range of bacteria while waiting for the results
• broad spectrum antimicorbials are also used for polymicrobial identification of the infecting pathogens. can also be used as prophylactic prevention of infections with surgery/invasive procedures
• broad spectrum may be selected to treat an infection when a narrow spectrum drug fails because of development of drug resistance
• the risk associated with broad spectrum is that they will also target normal microbiota, increasing risk of superinfection.
• superinfection is when a patient have a pre existing infection. it develops when the antibacterial intended for the preexisting infection kills the microbiota, allowing another pathogen resistant tot the antibacterial to proliferate and cause secondary infection. example -- yeast infections (candidiasis) and pseudomembranous colitis by clostridium difficile, fatal.