antibacterial agents

polymixin B MOA

increase permeability of bacterial cell wall

moa of PCN, cephalosporins, bacitracin, vancomycin

inhibitino of cell wall synthesis

moa of aminoglycosides, tetracyclines, macrolides, chloramphenicol, clindamycin

inhibition of protein synthesis

MOA of sulfonamides

inhibition of folic acid synthesis

MOA of fluorinated quinolones

interference w DNA synthesis

what do we chose if possible: bactericidial or bacteriostatic

bactericidal

use an antibiotic _____ for the organism rather than a wide or broad spectrum

specific

use route of admin that will ensure adequate _______ of hte drug

conc

continue ____________ even if pt responds quickly

full course

• finish the antibiotic so we don’t create resistance/superbug

overuse of antibacterials can disturb normal flura and lead to superinfections. side effects include:

1. GI upset

2. destruction of gut microbiome and free radical issues

which of the following antibacterial classes will distupt the gut microbiome

all of them

inhibitors of cell wall synthesis

B lactam: penicillin and cephalosporins

• bactericidal

• mainly affect gram positive; little gram negative

  • peptidoglycan layer more easily targeted in gram pos

antibacterials targeting cell wall synthesis are selectively toxic to bacteria. why

human cells do not contain cell wall

few adverse effects

what are the beta lactams

1. penicillins

2. cephalosporins

this structure creates cross allergy potential

if someone has a severe penicillin allergy there is a _______ chance they will react to cephalosporin

3-10

• bc of b lactam ring

where do we use beta lactam in optometry

1. oral:

   1. acute dacryocystitis

   2. preseptal cellulitis

   3. internal hordeolum

what class are carbapenem and monobactam

linked to beta lactams

• penicillin - carbaPENem

• monobactam - beta LACTAM

penicillins should be taken on full/empty stomach?

1. should be taken on an empty stomach

   1. 2 hours before a meal

   2. 4+ hours after a meal

2. EXCEPTION:

   1. amoxicillin/clavulanate (augmentin)

Natural penicillins

• penicillin G and Penicillin VK

  • VK = inconvieniant so not really used

• soectrum of activity - narrow spectrum

  • gram pos cocci (non resistant staph and strep spp.)

antistaphulococcal penicillins drugs

1. nafcillin (IV)

2. Dicloxacillin (PO)

3. methicillin

4. oxacillin

5. cloxacillin

tester - tells

antistaphylococcal penicillins spectrum of activity

narrow

some streptococcal

DO NOT COVER MRSA!!

ONLY COVER MSSA - Methicillin-sensitivie Staph aureus

extended spectrum penicillins (aminopenicillins) drugs

1. amoxicillin

AMINO SIdE CHAIN EXTENDS GRAM NEGATIVE COVERAGE

spectrum of activity of aminopenicillins (Extended Spectrum Penicillins)

1. similiar to natural penicillins in terms of gram + coverage (non resistant staph and strep)

2. streptococcus pneumoniae at high doses

3. inc gram neg coverage due to amino side groups

   1. haemophilus influenze

   2. moraxella catharrhalis

   3. typical organisms

      1. show up as gram pos or gram neg

         1. atypical does not show up on gram stain

b lactamase production

1. enzyme

2. most common mech of resistance

3. H flu and M cat produce beta lactamase

4. destroy antibiotic

amoxicillin/clavulonate (Augmentin)

1. beta lactam/beta lactamase inh

   1. has a beta lactamase inhibitor portion

2. protects it

3. augmented amoxicillin

amoxicilliln/ clavulanate (augmentin) spectrum of activity

1. similiar ot natural penicillins in terms of gram + coverage

2. streptococcus pneumoniae at high doses

3. inc gram neg coverage due to amino side group

   1. haemophilus influenzae

   2. m cat

   3. typical organisms

augmentin in safety

1. safe in birth to death in age

   1. any one less than 12 is dosed on weight

2. safe in pregnancy and breastfeeding

entended spectrum penicillins anti-pseudomonal

1. piperacillin (pipracil)

2. IV ONLY

1. piperacillin (pipracil) spectrum of activity

1. gram - infections

   1. esp pseudomonas aerginosa

Penicillin side effects

1. diarrhea - its disrupting gut microbiota

   1. c diff diarhhea is a bad

2. allergy

   1. swollen eyes/lips/face/mouth; itchy tongue; resp issues, full body hives = DO NOT GIVE

   2. MIGHT ALSO CROSS REACT W CEPHALOSPORINS

      1. 3-10 percent

cephalosporins

1. bactericidal

2. cell wall synthesis inh

3. generations

   1. 1 most gram + coverage adn elast gram - coverage

   2. 2

   3. 3

   4. 5

   5. highest gen = most gram - coverage and least gram + coverage

first gen cephalosporin drugs

Cefazolin (Ancef)

• used for surgery

Cephalexin (Keflex)***

first gen cephalosporin spectrum of activity

• amoxicillin and augmentin have this same list

2nd generation cephalosporin drugs

Cefaclor (Ceclor) (oral)

Cefuroxime (Ceftin) (oral)

cefoxitin

• **Little bit of anaeobic coverage

3rd gen cephalosporin drugs

1. cefixime

2. ceftriaxone

3. ceftazidime

ADR cephalosporin

1. hypersensitivity

2. cross sensitivity w penicillins - 3-10% chance

3. superinfection

bacitracin

1. cell wall synthesis inh

2. bactericidal

3. primarilly used topically bc of bad renal toxicity

4. Ung - ointment

   1. you cant put a preservative in an ointment

whats bacitracin used for

staph blepharitis

ADR bacitracin

1. contact dermatitis

2. superinfectin if with ohter wide spectrum drugs

3. no systemic abs w topical use

vancomycin

1. cell wall synthesis inh

2. GRAM POS ONLY

3. bactericidal

4. MRSA AGENT

5. IV only for system infection

6. PO ONLY treats GUT infection (not systemic) - C diff —> MOUTH TO ANUS

7. reserved for potentially blinding conditions

   1. endophthalmitis

   2. bacterial ulcer

   3. MRSA keratoconjunctivitis

ADR vancomyocin

1. oto and nephrotoxicity

   1. when combined w luke diuretics

2. Red Man syndrome

increase permeability to bacterial cell wall drugs

1. polymyxin B

2. gramicidin

polymixin B

1. bactericidal

2. gram negative: pseudomonas

3. ONLY TOPICALLY

ADR polymixin B

1. irritation

2. allergy

3. no significant systemic effects when used topically

protein synthesis inhibitors

1. 30 S ribosomal subunit

   1. aminoglycosides

   2. tetracyclines

2. 50 S ribosomal subunit

   Chloramphenicol

   Erythromycin (Macrolides)

   Lincosamide (Clindamycin)

   Linezolid

BI AT 30 CELL AT 50

azithromycin (zithromax, Zpak)

1. erythromycin

2. Zpak - 5 days of tablets

3. tri pak

whats the topical azithromycin and whats it used for

1. azasite

1. bacterial conjunctivitis

2. meibomianitis

meibomian gland dysfxn treatment drugs

1. azithromycin - FULL DOSE

2. doxycycline - LOW DOSE

macrolides (azythromycin) treats

1. oral

   1. internal hordeolum - not dug of choice

      1. except in PCN allergies

         1. virtually 0 coverage for strepto pneumonia

         2. not drug og choice because you are guessing

ADR macrolides (azythromyocin)

1. safe

2. QTc prolongation (cardiac arrhythmia)

   1. arrhythmia - azithromycin

3. GI upset *****

4. hepatitis

5. mild allergic reactions

6. hearing loss w large doses - very rare

whats azasite used for

bacterial conjunctivitis

which drugs are sage to use in pregnancy and babies and breastfeeding

1. penicillin

2. cephalasporin

3. azasites