Medication Summary
The goals of pharmacotherapy are to reduce morbidity, prevent complications, and eradicate the infection. The FDA approved three newer antibiotics, oritavancin (Orbactiv), dalbavancin (Dalvance), and tedizolid (Sivextro), for the treatment of acute bacterial skin and skin structure infections. These agents are active against Staphylococcus aureus (including methicillin-susceptible and methicillin-resistant S aureus [MSSA, MRSA] isolates), Streptococcus pyogenes, Streptococcus agalactiae, and Streptococcus anginosus group (includes Streptococcus anginosus, Streptococcus intermedius, and Streptococcus constellatus), among others. For complete drug information, including dosing, see the following monographs:
Antibiotics
Class Summary
Antimicrobial therapy must cover all likely pathogens in the context of the clinical setting.
Clindamycin (Cleocin)
Clindamycin is a lincosamide indicated for serious skin and soft tissue staphylococcal infections. It is also effective against aerobic and anaerobic streptococci (except enterococci). As much as 20% of group B streptococci may be resistant. Clindamycin inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest.
Aqueous penicillin G (Pfizerpen)
Aqueous penicillin G interferes with the synthesis of cell wall mucopeptide during active multiplication, resulting in bactericidal activity against susceptible microorganisms.
Nafcillin (Nalipen in dextrose)
Nafcillin is initial therapy for suspected penicillin G–resistant staphylococcal infections. Use parenteral therapy initially in severe infections. Owing to thrombophlebitis, particularly in elderly patients, administer parenterally only for the short term (1-2 d); change to oral route as clinically indicated.
Vancomycin
Vancomycin is a potent antibiotic directed against gram-positive organisms and active against Enterococcus species. Vancomycin is useful in the treatment of patients with septicemia and skin structure infections. It is indicated for patients who cannot receive or have failed to respond to penicillins and cephalosporins or who have infections with resistant staphylococci (eg, MRSA). For abdominal penetrating injuries, combine with an agent active against enteric flora and/or anaerobes.
Use creatinine clearance to adjust dose in patients with renal impairment.
Oxacillin (Bactocill in Dextrose)
Oxacillin is a bactericidal antibiotic that inhibits cell wall synthesis. It is used in the treatment of infections caused by penicillinase-producing staphylococci. Oxacillin may be used to initiate therapy when staphylococcal infection is suspected.
Tedizolid (Sivextro)
Tedizolid is an oxazolidione antibiotic; its action is mediated by binding to the 50S subunit of the bacterial ribosome, resulting in inhibition of protein synthesis.
Oritavancin (Orbactiv)
Oritavancin is a lipoglycopeptide antibiotic that exerts concentration-dependent bactericidal activity.
Dalbavancin (Dalvance)
Dalbavancin is a lipoglycopeptide antibiotic; it interferes with cell wall synthesis by binding to D-alanyl-D-alanine terminus of the stem pentapeptide in nascent cell wall peptidoglycan, thus preventing cross-linking.
Dalbavancin is bactericidal in vitro against Staphylococcus aureus and Streptococcus pyogenes at concentrations observed in humans at recommended doses.
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Description of M proteins and streptococcal toxins.
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Group A streptococci cause beta hemolysis on blood agar.
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Group A streptococci on Gram stain of blood isolated from a patient who developed toxic shock syndrome. Courtesy of T. Matthews.
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This schematic shows interaction among T-cell receptor, superantigen, and class II major histocompatability complex. The binding of superantigen to class II molecules and T-cell receptors is not limited by antigen specificity and lies outside the normal antigen binding sites.
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Progression of soft tissue swelling to vesicle or bullous formation is an ominous sign and suggests streptococcal shock syndrome. Courtesy of S. Manocha.
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A 46-year-old man presented with nonnecrotizing cellulitis and streptococcal toxic shock syndrome. The leg was incised to exclude underlying necrotizing infection. Courtesy of Rob Green, MD.
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A 46-year-old man presented with nonnecrotizing cellulitis and streptococcal toxic shock syndrome. This patient also had streptococcal pharyngitis. Courtesy of Rob Green, MD.
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A 46-year-old man presented with nonnecrotizing cellulitis and streptococcal toxic shock syndrome. The patient had diffuse erythroderma, a characteristic feature of the syndrome. Courtesy of Rob Green, MD.
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A 46-year-old man presented with nonnecrotizing cellulitis and streptococcal toxic shock syndrome. The patient had diffuse erythroderma, a characteristic feature of the syndrome. The patient improved with antibiotics and intravenous gammaglobulin therapy. Several days later, a characteristic desquamation of the skin occurred over palms and soles. Courtesy of Rob Green, MD.
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A 58-year-old patient presented in septic shock. On physical examination, progressive swelling of the right groin was observed. On exploration, necrotizing cellulitis, but not fasciitis, was present. The cultures grew group A streptococci. The patient developed severe shock (toxic shock syndrome). The CT scanning helped evaluate the extent of infection and exclude other pathologies, such as psoas abscess, osteomyelitis, and inguinal hernia.
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A 58-year-old patient presented in septic shock. On physical examination, progressive swelling of the right groin was observed. On exploration, necrotizing cellulitis, but not fasciitis, was present. The cultures grew group A streptococci. The patient developed severe shock (toxic shock syndrome). The CT scanning helped evaluate the extent of infection and exclude other pathologies, such as psoas abscess, osteomyelitis, and inguinal hernia.
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A 58-year-old patient presented in septic shock. On physical examination, progressive swelling of the right groin was observed. On exploration, necrotizing cellulitis, but not fasciitis, was present. The cultures grew group A streptococci. The patient developed severe shock (toxic shock syndrome). The CT scanning helped evaluate the extent of infection and exclude other pathologies, such as psoas abscess, osteomyelitis, and inguinal hernia.
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Necrotizing cellulitis of toxic shock syndrome.
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Soft-tissue infection secondary to group A streptococci, leading to toxic shock syndrome.
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Extensive debridement of necrotizing fasciitis of the hand.
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The hand is healing following aggressive surgical debridement of necrotizing fasciitis of the hand.
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Necrosis of the little toe of the right foot and cellulitis of the foot secondary to group A streptococci.
