Penicillin allergy
- Includes: all '-cillin's, including Augmentin (amoxicillin/clav) and Zosyn (piperacillin/tazo)
- May also react to: cephalosporins, carbapenems
- Safe to give: vancomycin
Empiric treatments by system:
Broad-spectrum abx
- Vancomycin + ceftriaxone OK for most cases
- If concerned for Pseudomonas (HCAP, sepsis, etc.) then vanc + cefepime
- Vanc + Zosyn will also cover pseudomonas, but much more likely to cause kidney injury
GI
- Diverticulitis - cipro 400 mg IV q12 + flagyl 500 mg IV q8, or augmentin
GU
- UTI
- STIs
- Gonorrhea - Ceftriazone 250 mg IM x1 (anti-gonococcal) AND azithromycin 1g PO x1 (anti-chlamydial)
- Chlamydia - azithromycin 1g PO x1 OR doxy 100 mg BID x 7d
Skin
- Non-purulent (cellulitis, erysipelas, necrotizing fasciitis)
- Mild - PO - penicillin VK 500 mg QID (ac+hs), or clindamycin 300 mg TID
- Mod - IV - penicillin G 1-2 million U q6h, or cefazolin (Ancef) 1g q8h
- Severe - Vanc + Zosyn (and surgical consult to rule out nec fasc)
- Necrotizing fasciitis
- Clinical diagnosis - non-purulent, red-purple → blue-grey, bullae, gangrene, ± crepitus
- Risk factors - diabetes, obesity
- Type 1 (polymicrobial) vs. type 2 (monomicrobial - strep. pyogenes, staph aureus, peptostreptococcus)
- Purulent - MRSA coverage (see below)
Gram stain - common organisms and 'buzz words'
| Gram positive | |||
| GPC (cocci) | GPR (bacilli) | ||
| clusters | staph | anaerobic | clostridium |
| pairs/chains | strep (or enterococcus) |
||
| Gram negative | |||
| GNC (cocci) | GNR (bacilli) | ||
| neisseria |
e. coli pseudomonas |
||
C. difficile
| 1st occurrence Uncomplicated recurrence (< 3 mo since discontinuation of therapy) |
PO vanc 125 mg QID x 10d |
| > 2 recurrences or high risk for recurrence |
+PO Fidaxomicin 200 mg BID x 10d |
| Severe disease (WBC > 15, albumin < 3, +/- Cr > 1.5 x baseline) |
PO vanc 125-500 mg QID |
| Complicated disease = hypotension/shock, ileus, megacolon |
PO vanc 500 mg QID + IV flagyl 500 mg TID |
- *Flagyl no longer recommended (new IDSA guidelines); was only used b/c cheaper (vanc is superior)
- +Fidaxomicin is $$$ but a/w less frequent recurrence compared to vanc
- Don't bother re-checking stool toxin assays until at least > 4 weeks after completion of therapy; high percentage are still positive
- Frequent culprits of C. diff: fluoroquinolones, clindamycin, cephalosporins, penicillins
- Other risk factors: PPI (acid suppression), ↑ age, IBD, immunosuppression
- Progression to fulminant colitis/toxic megacolon (acute abdomen, lethargy, fever w/ dilated colon/paralytic ileus on imaging) = surgical consult, colectomy
MRSA
| PO (mild skin/soft tissue infxn) |
Bactrim | 1-2 tabs DS BID | AIN, DRESS |
| Doxycycline | 100 mg BID | Photosensitive rash, GI sx | |
| Clindamycin | 300-450 mg QID | Inducible resistance; avoid if local resistance > 10% | |
| Linezolid (if cannot tolerate other agents) | 600 mg BID (100% PO bioavailability) | Serotonin syndrome | |
|
IV |
Vancomycin | 15-20 mg/kg/dose q8-12 hr, < 2 g/dose | Red man syndrome |
| Daptomycin | 4-6 mg/kg qd | Weekly CK (rhabdo), DRESS, eosinophilic pneumonia | |
| Linezolid | 600 mg BID | Serotonin syndrome | |
| Clindamycin | 600-900 mg q8h | Inducible resistance; avoid if local resistance > 10% | |
| Ceftaroline | 600 mg q12 |
- Add rifampin for prosthetics/endocarditis; add gentamicin for native-valve endocarditis
- Daptomycin not used in pneumonia
Pseudomonas
| Fluoroquinolone (only PO option) |
Ciprofloxacin |
400 mg q8 750 mg qd |
| Penicillin | Zosyn (pip/tazo) | 4.5 g q6 |
| Cephalosporins (not ceftriaxone) |
Ceftazidime Cefepime |
2 g q8 |
| Carbapenems (not ertapenem) |
Imipenem Meropenem |
500 mg q8 1 g q8 |
| Aminoglycoside | Gentamicin Tobramycin Amikacin |
|
| Monobactam | Aztreonam | 2 g q8 |
VRE
- Vancomycin-resistant enterococcus
- E. faecium >> E. faecalis
- Ampicillin + gentamicin
- E. faecium more often resistant to beta-lactams/aminoglycosides - use daptomycin, linezolid, or tigecycline
