Antimicrobials Patho Flashcards
Antimicrobials
Meds that slow bacterial growth or inhibit it
Characteristics of antimicrobials
- Occur naturally
- synthetic or semi-synthetic
- bactericidal or bacteriostatic
- broad or narrow spectrum
Bacteriostatic vs Bacteriocidal
Static=slow or inhibit bad growth
Cidal=kill bac
Selective toxicity
Toxic to certain cells while sparing others in close proximity
Resistance
Ability to live against antimicrobials or render anti-microbial ineffective
- innate or acquired
Super infections
- Occur after tx for primary infections
- c.diff and candidasis
Prophylactic abx
- prevent infx
- for high risk procedures or pts—orthopedic, cardiac, abdominal, endocarditis (dental procedures), immunocompromised
Factors in the choosing of abx
- community vs hospital acquired
- site of infx
- suspected organism and what it is susceptible to—helps limit resistance
What should you ALWAYS try to do before starting abx?
Get a culture
- if pt is critically ill, you might not be able to wait, but giving abx may prevent organism from growing in the culture
- if meningitis or sepsis, will start abx (for meningitis, need one that crosses BBB)
What does sputum tell you?
Gram, C&S
What does urine tell you
Urinalysis, C&S
Blood analysis
Anaerobic vs aerobic bottles
- test for each type of bac
- one should always be peripheral
- be v careful with cleaning bottles
Minimum inhibitory concentration (MIC)
Put different concentrations of abx in with bac; look for the lowest amt of drug that inhibits bac growth (does not kill) and prescribe that to reduce resistance
- report it as susceptible or resistant
Drug sensitivity of ogranism
Determine what drug is effective
- smear abx on plate with bac, look for circle with not growth to see efficacy
Allergies to drugs
- if allergic, no work (rash, welts, anaphylaxis—true allergy)
- PCN allergy, might also be allergic to cephalosporins
- Sulfa allergies—Bactrim
- age—can develop at any age
Pt char that determine how drugs will work
- age—determines response to drug
- liver and renal dx—may have lower abx tolerance
- allergies
- site of infx
- pt defense
- org causing infx
- how sick pt is (local vs systemic)
- time vs concentration—earlier usually better to give, peak and trough
Why do you need to draw peak and trough for abx?
Certain drugs need specific concentration to achieve results
Nosocomial infx
Occurs in HC facility
Infections in HC
- inc virulence from innate resistance (drug resistant, class resistant (CRE), multiple class resistant)
- inc sus bc illness, dec immune response, surgery, invasive procedure
- disrupted skin barriers–CLABSI, CAUTI, NG tubes
Post op infection risk
- respiratory–atelectasis, inc risk pneumonia
- surgical wound infx (DEHISCENCE)
- UTI–post op catheter
Abx prescribing
- pt demand them
- 4x risk of abx sending you to ED for SE than chance they will help
Issues with abx failure
- wrong drug
- start too late or wrong dose
- not take long enough and comes back
- drug can’t get to infx
2 MOAs for antimicrobials
- interfere with cell wall synthesis causing cell death (Carbapenems, PCNs, cephalosporins, vancomycins)
- inhibit/alter protein synthesis (transcription or translation)
Beta-lactam antibiotics
- give first
- given with PCNs, cephalosporins, carbs, and monos
- given for bacteria that produce beta-lactamase enzyme
CRE
- carbapenem-resistant enterobacteriacease
- public health emergency
- HAI–hygiene necessary
Peak
highest drug conc; drawn 15-30 minutes after giving usually
Trough
lowest drug conc; draw 30 min before next admin usually
