Review Of Anti-mircobial Mechanisms Flashcards
Infections of the upper respiratory tract induce
Acute Ottis media (middle ear)
Acute bacterial rhinosinusitis ( sinus infections)
Bacterial pharyngitis (strep throat)
Infections of the lower respiratory tract include
Chronic bronchitis
Community-acquired pneumonia
Hospital acquired pneumonia
What is the general treatment sequence for bacterial infections?
Treated empirically until a definitive treatment for the specific agent is present
- empirically tx is implemented based on most likely causative organisms
Patient history and factors play a critical role in this
Antimicrobial activity to take into consideration when choosing anti-microbial
Gram (+) vs Gram (-) vs mycobacterium
Aerobic vs anaerobic
Inhibtors of cell wall synthesis includes what?
B-lactam drugs:
penicillins (gram (+) only)
cephalosporins (gram (+/-)
carbapenems
Glycopeptides
- vancomycin (pretty much only used in MRSA)
MOA:
- act by preventing synthesis of the peptidoglycan cell wall
- B-lactams act by inhibiting transpeptidase
- glycopeptides act by inhibiting D-alanine residues needed for peptidoglycan cross-linking
Protein synthesis inhibtors include what?
Lincosamides (gram (+) only, disrupts 50s ribosome)
- Clindamycin
Macrolides (broad spectrum, disrupt 50s ribosome)
- clarithromycin
- azithromycin
- erythromycin
Aminoglycosides (broad spectrum, disrupt everything pretty much)
- gentamicin
- tobramycin
Tetracyclines (broad spectrum, disrupts 30s ribosome)
- tetracycline
- doxycycline
- minocycline
DNA/RNA synthesis inhibitors include what?
Fluroquinolones
- direct inhibtors that disrupt topoisomerases in microbes
- causes destability and inability to prevent supercoiling
- levofloxacin (causes destability of tendons in patients)
- moxifloxacin
- ciprofloxacin
Folate synthesis inhibtors
- indirectly prevent DNA synthesis due to competitively inhibiting folic acid synthesis
- sulfonamides (inhibts dihydropteroate synthase)
- trimethoprim (inhibts dihydrofolate reductase)
Generations of cephalosporins
1st generation
- cefadroxil
- pretty much only gram (+) activity
2nd generation
- cefuroxime
- mix of gram (+/-)
3rd generation
- cefdinir
- ceftriaxone
- cefotaxime
- cefpodoxime
- more gram (-) activity w/ very mild (+)
4th generation
- cefepime
- only gram (-) activity
- Anti-MRSA = ceftaroline*
Treatment of acute otitis media
Overall Goal is:
- reduce pain
- deliver antibiotics once diagnosis is confirmed
common agents that cause this are:
- streptococcus pneumonia
- haemophilus influenza
- moraxella catarrhalis
(all often possess B-lactam resistance)
specific treatment
1) high dose amoxicillin (S. Pneumoniae is most effective for this treatment)
- lasts 10 days
2) use clindamycin if amoxicillin did not kill all
Treatment of acute bacterial rhinosinusitis
Overall Goal is:
- reduce sings/symptoms
- limit antibiotic therapy unless you can confirm it is a microbe (must distinguish viral from bacterial)
- eradicate infection completely (prevent complications/chronic disease)
common agents that cause this are:
- streptococcus pneumonia
- haemophilus influenza
- moraxella catarrhalis
- also viral infections
(all often possess B-lactam resistance)
Specific TX:
- non-bacterial = OTC decongestants and saline/steam inhalation
- bacterial = amoxicillin-clavulanate is first line
(must have clavulanate to counteract amoxicillin resistance)
can also use tetracyclines but only in adults not children (stunts bone growth)
Treatment of acute bacterial pharyngitis
Overall Goal is:
- improve signs/symptoms
- limit ADRs
- prevent tranmission
- prevent complications (rheumatic fever/abscesses)
- common agents that cause this are:*
- streptococcus pneumonia
- GAS bacteria (is strep throat at this point)
Specific treatment
- only give antibiotics if you know what GAS it is
- supportive care = antipyretic/analgesics and NSAIDS
- 1st line = penicillin or amoxicillin
- 2nd line = cephalosporins and macrolides
- can use rifampin as a synergist in carriers of strep throat*
Treatment of acute exacerbation of chronic bronchitis
Treatment goals
- reduce severity of chronic symptoms
- stop current acute exacerbation
- prolong intervals between future exacerbation
- most common infectious agents*
- H. Influenza
- M. Catarrhalis
- S. Pneumoniae
- E. Coli
- note: these may not be present*
Specific treatment:
- if bacterial: ampicillin or/and amoxicillin/clavulanate therapies
- can also throw in Fluroquinolones*
Treatment of bacterial pneumonia
Treatment goals
- eradication of organisms
- minimized morbidity
- cost-effective treatment
Need to determine hospital or environmental acquired
Atypical pneumonia includes
- mycoplasma
- legionella
- cant use B-lactams or glycopeptides since they have no wall*
