Group A Beta Hemolytic Strep. pyogenes

Staphylcoccus aureus, historically MSSA

Anti-Staph Penicillinase Resistant

Dicloxacin PO

Nafcillin IV

Oxacillin IV

1st Gen Cephalosporins 

Cephalexin PO

Cefazolin IV

Allergic Patients:

Clindamycin (causes C. diff overgrowth)

Macrolides (resistance developing)

Bactrim

Clindamycin

Doxycycline

Vancomycin and newer MRSA agents best for severe infections

Avoid fluoroquinolones (resistance developing)

Group A Hemolytic Strep. pyogenes

Staph. aureus (MSSA)

Anti-Staph Penicillinase Resistant

Dicloxacin PO

Nafcillin IV

Oxacillin IV

1st Gen Cephalosporins 

Cephalexin PO

Cefazolin IV

Allergic Patients:

Clindamycin (causes C. diff overgrowth)

Macrolides (resistance developing)

• Superficial Cellulitis with extensive lymphatic involvement
• Borders well defined by elevation
• Lower extremities most common

Group A Beta Hemolytic Strep pyogens (primarily)

Rarely:

Group B Beta Hemolytic Strep agalactiae in newborns

Staph. aureus

DOC: Penicillin (any will work) -- IV, IM, or PO depending on severity

Anti-Staph Penicillins, Cephalosporins are also OK

Allergy to Beta Lactams:

Clindamycin or Macrolide

Keep in mind: dying organisms release toxins so infection might appear to worsen with treatment

Group A Strep, Staph. aureus, or Clostridium

Can produce deadly toxins

For serious infection combine:

Beta-Lactam or Cell wall agent with Clindamycin

Possible with Linezolid (for MRSA) too

• Rare, but very serious
• Progressive destruction of fascia, subcutaneous fat, and muscle
• Most frequently occurs below the diaphragm (abdomen, perineum, lower extremities)

• Diabetes
• Surgery/Local Trauma
• Recent infections

Bacteroides

Peptostreptococcus

Streptococci

Enterobacteriaceae

Group A Beta Hemolytic Strep pyogenes

Clostridium perfringens

Surgical Debridement Plus:

(you need something with G+, G-, and Anaerobic activity)

Penicillin/Beta-Lactamase Inhibitor

OR

Carbepenems

PLUS:

Vancomycin or alternative (linezolid)

+/-

Clindamycin or Metronidazole (for abcess)

• Often Polymicrobic
• Staph and Strep very common
• G- (E.coli, Klebsiella, Proteus, P. aeruginosa)
• Anaerobes (Bacterioides frigalis, Peptostreptococcus)

G- love moist, dark places

Anaerobes live in harmony with aerobes, poor O2 supply to site of infection

• Mild cases similar to cellulitis treatment

Amoxicillin/Clavulanate PO

• Moderate cases need IV

Ampicillin/Sulbactam IV

Ertapenem IV

• Severe/Life-Threatening Infections

Imipenem/Doripenem/Moripenem IV

Piperacillin/Tazobactam

• Other Options (for allergic patients)

Clindamycin plus Ciprofloxacin or Aztreonam

Levofloxacin plus metronidazole

Moxifloxacin

10-14 days if mild-moderate

21 days if severe

Imipenem, Doripenem, Meropenem

Piperacillin/Tazobactam

• Clindamycin + Ciprofloxacin or Aztreonam
• Levofloxacin + Metronidazole
• Possibly Moxifloxacin alone (Strep., Enteric, and Anaerobe activity)

Topical for minor sores:

Silver sulfadiazine, mafenide for burns

Triple Antibiotic Ointment (neomycin, bacitracin, polymyxin)

Systemic for severe sores:

Same as for polymicrobial infections

G+, G-, and Anaerobes

Staph and Strep

G-

Anaerobes if deep

Biospy, Culture from Surgery

Elevated WBCs, ESR, and CRP

Imaging

Hematogenous

Infection spreads through bloodstream

Usually in long bones of children

Vertebral in adults over 50

Contiguous

Infection spreads from adjoining tissue

Penetrating Trauma

Pressure Ulcers

Children

S. aureus moss prevalent (MSSA)

H. influenzae type B if unvaccinated

Adults

S. aureus

E. coli (rare)

Mycobacterium (extremely rare)

S. aureus, Strep

E. coli, Proteus

P. aeruginosa (rare)

Anaerobes

Oxacillin

Nafcillin

Cefazolin

Treat for 4-6 weeks

First 2 weeks are IV

Start with Vancomycin (MRSA is likely)

+/- a G- drug if contiguous (3rd Gen Cephalosporin)

Treat for 4-6 weeks

IV for entire duration

Anti-Pseudomonal Beta Lactam (Ticarcillin, Piperacillin)

+/- an Aminoglycoside

Ciprofloxacin (levofloxacin) can be converted to PO