Antibiotic Dosing: Class (common abx) Antibiotic Dosing: Bacteria DOC Penicillin’s

1st Generation: -Pen V: 250-500mg q6 PO

-Pen G: 250,000 units/kg/day IV

2nd Generation: -Dicloxacillin: 250mg q6 PO

(PCNase Resistant PCN) -Oxacillin: -2g q4 IV

-Nafcillin: 1-2g q4 IV

3rd Generation: -Amoxicillin: 500mg q8 PO

(AminoPCN) -Ampicillin: 1g q4-6 IV

4th Generation: -Augmentin: 875mg q12 PO (Amox-/clav-), RD = 250mg-500mg q24h

(β-lactamase PCN) -Unasyn: 1.5-3g q6 IV (Amp-/sulbactam)

-Zosyn: 3.375-4.5g q6 IV (Piper-/tazobactam)

-Timentin: 3.1g q6 IV (Ticar-/clavulanate)

Cephalosporin’s

1st Generation: -Keflex (cephalexin): 500mg q8 PO or 750mg PO bid, RD = 250 q12-24h

-Duricef: 2g q24 PO

-Ancef: 1g q8 IV

2nd Generation: -Ceftin: 500mg q12 PO

-Zinacef: 1.5g q8 IV

-Mefoxin: 1g q6 IV

3rd Generation: -Omnicef (Cefdinir): 300mg q12 PO, RD = 300mg every other day

-Vantin: 400mg q12 PO

-Rocephin: 1g q24 IV

-Fortaz: 1g q8 IV

-Cefobid: 2g q12 IV

4th Generation: -Maxipime: 2g q12 IV

Quinolones- inhibits DNA gyrase, bacteriocidal

2nd Generation: -Ciprofloxacin: 750mg q12 PO/ 400mg q12 IV, RD = 250mg q12h

3rd Generation: -Levofloxacin (Levaquin): 500-750mg q24 PO/IV, RD = 250mg q24h

4th Generation: -Tequin: 400 q12 PO/IV

-Avelox (moxloxacin): 400 q24 PO

Macrolides- binds to 50s ribosome inhibiting protein synth, bacteriostatic

-Biaxin: 500mg q12 PO

-Ketek: 800mg q24 PO

-Zithromax: 500 q12 IV/ 500mg PO Day 1; 250 mg PO Day 2-5

-Erythromycin- 500mg q6 PO

Carbapenems -Invanz: 1g q24 IV

-Primaxin: 500mg q8 IV

-Merrem 1g q8 IV

Aminoglycosides -Amikacin: 1500mg/day check trough after 3rd dose

-Tobramycin: 3-5mg/kg/day

-Gentamycin: 3-5mg/kg/day

Tetracyclines -Minocycline (Minocin): 100mg q12 PO/IV

-Doxycycline: 100mg q24 PO

-Tetracycline: 500mg q6 PO

-Tygacil (Tigecycline): 100mg loading dose; then 50mg q12 IV

Misc -Bactrim DS: 160/800mg q24 PO, RD = 1DS q24h

-Aztreonam: 1g q8 IV

-Vancomycin: 1g q12 IV, 125mg po qid for C.difficile colitis only

-Clindamycin: 600mg q8 IV; 300mg q6 PO

-Zyvox (linezolid): 600mg q12 PO/IV

-Cubicin (Daptomycin): 4mg/kg q12 IV

-Synercid (quinupristin/dalfopristin): 7.5mg/kg q8 IV

-Flagyl: 500mg q8 PO

-Rifampin: 300mg q12 PO/IV, RD = 300mg q24h

-Primaxin (imipenem/cilistatin): 500mg q6h IV

-Ertapenem (Invanz): 1g q24h IV

Staph Aureus

-PO: Keflex -500mg PO tid or 750mg PO bid

Clindamycin -300mg PO qid

Zithromycin -500mg PO day 1, 250mg PO days 2-5

-IV: Ancef -1g IV q8

Vancomycin -1g IV q12

Clindamycin -600mg IV q8

Streptococcus

-PO: Keflex -500mg PO tid or 750mg PO bid

Clindamycin -300mg PO qid

-IV: Ancef -1g IV q8

Vancomycin -1g IV q12

Clindamycin -600mg IV q8

MRSA

-IV: Vancomycin -1g IV q12

-PO: Bactrim -1 tablet PO bid

Enterococcus

-PO: Amoxicillin -250-500mg tid

Augmentin -875mg bid or 500mg tid (or bid)

Zyvox -600mg PO bid

-IV: Vancomycin -1g IV q12

Zyvox -600mg IVq12

VRA/VRE

-PO: Zyvox (linezolid) -600mg PO bid

-IV: Zyvox (linezolid) -600mg IV q12

Synercid -7.5mg/kg/hr over 1 hour q12

Pseudomonas

-PO: Ciprofloxacin -250-750mg PO bid

-IV: Ciprofloxacin -400mg IV q12

Fortaz -2g IV q12

Aztreonam -1g IV q8

E.coli, Proteus

-PO: Keflex -500mg PO tid or 750mg PO bid

Cipro -250-750mg PO bid

Levaquin -500mg PO qday

Tequin -400mg PO qday

-IV: Ancef -1g IV q8

Cipro -400mg IV q12

Levaquin -500mg IV qday

Tequin -400mg IV qday

DOC Alternatives

-Aerobic Gram (+) Cocci

Staph aureus 1-Ceph Vanco, Clinda, Azithromycin

MRSA Vanco Bactrim, Cubicin, Zyvox, Clinda

Staph epi 2-PCN 4-PCN, 1,2-Ceph, Vanco

MRSE Vanco Zyvox, Cubicin, Synercid

Enterococcus 3-PCN Vanco, Tetracyclines, Quinolones

VRE Linezolid Macrobid, Cubicin, Chloramphenicol

Strept pyogenes (Group A) 3-PCN 4-PCN, 1,2-Ceph, Vanco, Clinda

Strept agalactiae (Group B) 3-PCN 4-PCN, 1,2-Ceph, Vanco, Clinda

Strept bovis (Group D) 3-PCN 4-PCN, 1,2-Ceph, Vanco, Clinda

Strept Viridans 3-PCN 4-PCN, 1,2-Ceph, Vanco, Clinda

-Anaerobic Gram (+) Cocci

Peptostreptococcus Clinda 3-PCN, 4-PCN, Carbapenems

-Aerobic Gram Positive Rods

Bacillus anthracis Cipro 3-PCN, Vanco, Clinda

Corynebacterium diphtheriae Macrolide Clinda,

Listeria Monocytogenes 3-PCN Vanco, Bactrim, Carbapenems

-Anaerobic Gram Positive Rods

Clostridium perfringens Ertapenam Vanco, Clinda, 4-PCN, Tetracyclines

Clostridium difficile Flagyl Vanco

Clostridium tetani Clinda Flagyl

-Aerobic Gram Negative Rods

Pseudomonas Zosyn 1,2-Quin, Aztreonam, Primaxin

E. coli 3-Ceph 4-PCN, Bactrim, Quinolones

Enterobacter Bactrim Quinolone, Aztreonam, Carbapenems

Proteus 3-PCN 3-Ceph, 4-PCN, Bactrim, Quinolones

Vibrio Tetracyclines Bactrim, Cipro

Y. pestis Aminoglycosides Bactrim, Cipro

Shigella Cipro Bactrim, Amp, 4-PCN

Salmonella Cipro 3-PCN, 4-PCN, Bactrim

Klebsiella 3-Ceph 4-PCN, Bactrim, 2-Quin, Aminoglycosides

Serratia 3-Ceph/ Zosyn, Bactrim, Aztreonam, Quin

E. Corrodens Augmentin Tetracyclines

P. multocida Doxycycline Bactrim, 3-PCN

-Anaerobic Gram Negative Rods

Bacteroides fragilis Ertapenam Clinda, Flagyl

-Aerobic Gram Negative Cocci

Neisseria Rocephin 3-PCN, Quinolones

-Spirochetes

Treponium pallidum 1-PCN Tetracyclines, Macrolides

Borrelia burgdorferi 1-PCN Amox, Macrolides

MRSA Drugs: ORAL

• CA-MRSA- Bactrim, Linezolid, Minocycline, Doxycycline, Clindamycin

• HA-MRSA- Linezolid

MRSA Drugs: PARENTERAL

• CA-MRSA & HA-MRSA - Quinupristin/Dalfopristin, Daptomycin, Tigecycline, Vanco

PCN Extended Spectrum: anti-pseudomonal PCNs):

• Carcenicillin, Pipercillin, Mezlocillin, Ticarcillin, Azlocillin

Vancomycin Peak/Trough:

• Monitor peaks (15-30mg/ml) & troughs (10-15mg/ml)

• Ototoxicity can be seen with ↑vancomycin peak levels (>80 ug/mL)

Surgical Prophylaxis:

Indications: prolonged surgery (>2hrs), use of implants, trauma surgery, immunocompromised

• Cefazolin 1g IV, Clindamycin 600mg IV, Vacnomycin 1g IV

Clindamycin susceptible / Erythromycin resistant staph

• Suspect inducible clindamycin resistance and ask lab to confirm with the “D test.”

Disulfiram Reaction Drugs: Moxalactam, Cefoperazone, Metronidazole, Cefomandol, Cefoetan

Empiric Therapy for Mammalian Bite Wounds

1) Ampicillin/sulbactam (Unasyn).

2) Amoxicillin/ clavulante (Augmentin).

3) Ciprofloxacin/Clindamycin (Cipro/Cleocin) *

Drug MOA/Coverage:

PCN: act on PCN binding protein to inhibit cell wall synthesis, bactericidal

Natural PCN- Strep, Non-PCNase Staph, Non-PCNase gonocooci, Clostridia

AminoPCN- Strep, exterococci, Gram (-): E.coli, P.mirabilis, Shigella, Salmonella

PCNase resistant- Staph (non-MRSA), Strep

β-Lactamase PCN- Staph (non-MRSA), Strep, Anaerobe (Bacteroides),

• Gram (-): enterobacter. pseudomonas: Zosyn (pipercillin-), Timentin (ticarcillin-)

• Ticarcillin/clavulanate: High sodium load (avoid in patients with CHF!!).

Cephalosporins: inhibit cell wall synthesis, bactericidal, cross reactivity in 5-15% with PCN allergy

1st Generation: Staph, Strep, Anaerobes

• Gram (-): E.coli, P.mirabilis, Shigella, Salmonella

2nd Generation: Staph (less than 1st), Strep (same as 1st),

• Extended Gram (-): H.influenza, Proteus, Klebsiella, E.coli

• Anaerobic (Bacteroides): cefmetazole, cefoxitin

3rd Generation: Staph, Strep (less than 1st & 2nd), Pseudomonas, Anaerobes. Neisseria

• Pseudomonas: ceftazadime, cefoperazone

4th Generation: greater Gram (-) coverage

Quinolones: inhibits DNA gyrase, bactericidal

• Staph (non-MRSA), Gram(-): Pseudomonas, Enterobacter

• CI in children: defects in cartilage

Aztreonam: Gram (-) aerobes (pseudomonas), NOT active against Gram(+) or aerobic organsims

Aminoglycosides: binds 30s ribosome to inhibit protein synthesis, bactericidal

• Adverse rxn: ototoxicity(irreversible), nephrotoxicity (reversible), neuromuscular

blockade

Sulfonamides (TMP/SMX- Bactrim)

• Trimethoprim: inhibits bacterial dihydrofolate reductase

• Sulfamethoxazole: inhibits folic acid production

• Staph (CA-MRSA), Strep, Gram (-): Pseudomonas

Macrolides: binds 50s bacterial ribosome inhibiting protein synthesis, bacteriostatic

• Mycoplasmic, Chlamydia, Legionella

• Gram (+): Pneumococcu, Strep, Staph, Cornybacteria

• Gram (-): Neisseria, Bordetella, B. Quintana, Camplobacter

Vancomycin: binds to D-ala D-ala and inhibits cell wall mucopeptide formation

• Only Gram (+): Staph (DOC MRSA), Strep

• Given PO to treat psuedomembranous colitis: 125mg po qid

Tetracyclines: binds 30s ribosomal subunit, avoid in pregnancy (affects bone growth of fetus)

• Staph, Strep, Gram (-): E.coli, Shigella, Klebsiella, H.influenza, some anaerobes

• 1st line therapy: Rocky Mountain Spotted Fever (Rickettsia), Q Fever (Coxiella)

Rifampin: acts directly on messenger RNA synthesis

• Listeria species, N.gonorrhoeae, H.influenzae and Legionella pneumophila

• Mycobacterium infections, including tuberculosis & leprosy.

Metronidazole:

• Anaerobes: B.fragilis, Clostridium, Peptostreptococcus, Prevotella

• 1st line for pseudomembranous colitis from C.difficile (2nd line = PO vancomycin)

Renal dosing

• DO NOT require dose adjustment: Moxifloxacin, Clindamycin, Azithromycin,

Linezolid, Minocycline, Metronidazole, Dicloxacillin

• DO require: Cipro, Levofloxacin, Cefdinir, Cephalexin, Amox/Clav, Rifampion,

TMP/SMX

Odor, Color and Appearance as Clues to the Infecting Organism

yellow pus S. aureus (coagulase positive Staph)

white pus S. epidermidis (coagulase negative Staph)

green pus/exudate P. aeruginosa

dishwater pus Strep. group A (necrotizing fasciitis)

draining sinuses /granules* Mycetoma (Madura foot)

Fruity odor P. aeruginosa

Foul, fetid odor Anaerobes (B.fragilis in diabetic foot)

Wood’s Light fluorescence

Coral red C. minitissimum

Green P. aeruginosa

Red Bacteroides melaninogenicus

Yellow Pityriasis versicolor