Medication Summary
Historically, penicillin G in dosages of 10-24 million U/d was the drug of choice. Recent studies show that protein synthesis inhibitors (eg, clindamycin, chloramphenicol, tetracycline) may be more effective by inhibiting the synthesis of clostridial exotoxins and lessening the local and systemic toxic effects of these proteins.
Antibiotics
Class Summary
These agents inhibit bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes, causing RNA-dependent protein synthesis to arrest.
Clindamycin (Cleocin, Cleocin Pediatric)
May be used for treatment of skin and soft tissue staphylococcal infections. Also effective against aerobic and anaerobic streptococci (except enterococci). Inhibits bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes, causing RNA-dependent protein synthesis to arrest.
Penicillin G (Pfizerpen)
Beta-lactam antibiotic that interferes with synthesis of cell wall mucopeptides during active multiplication, resulting in bactericidal activity against susceptible bacteria.
Metronidazole (Flagyl, Metro)
Imidazole ring-based antibiotic active against various anaerobic bacteria and protozoa. Used in combination with other antimicrobial agents (except Clostridium difficile enterocolitis).
Tetracycline
Semisynthetic antibacterial agent derived from Streptomyces cultures. Treats gram-positive and gram-negative organisms and mycoplasmal, chlamydial, and rickettsial infections. Inhibits bacterial protein synthesis by binding with 30S and, possibly, 50S ribosomal subunit(s).
Chloramphenicol
Binds to 50S bacterial-ribosomal subunits and inhibits bacterial growth by inhibiting protein synthesis. Effective against gram-negative and gram-positive bacteria.
Vancomycin
Vancomycin is active against Staphylococcus epidermidis. To avoid toxicity, the current recommendation is to assay vancomycin trough levels after the third dose in a sample drawn 0.5 hours before the next dose. Dose adjustment is possible in patients with renal impairment; the adjustment should be based on creatinine clearance.
Linezolid (Zyvox)
Linezolid is used as an alternative drug in patients allergic to vancomycin and for treatment of vancomycin-resistant enterococci. It is also effective against MRSA and penicillin-susceptible S pneumoniae infections.
This agent is an oxazolidinone antibiotic that prevents formation of the functional 70S initiation complex, which is essential for bacterial translation process. Linezolid is bacteriostatic against enterococci and staphylococci and bactericidal against most strains of streptococci.
Meropenem (Merrem IV)
Meropenem is a carbapenem with slightly increased activity against gram-negative organisms and slightly decreased activity against staphylococci and streptococci compared to imipenem. It is less likely to cause seizures and achieves superior penetration of the blood-brain barrier compared to imipenem.
Imipenem/cilastatin (Primaxin I.V.)
Imipenem-cilastatin is a carbapenem with activity against most gram-positive organisms (except MRSA), gram-negative organisms, and anaerobes. It is used for treatment of multiple-organism infections in which other agents do not have wide-spectrum coverage or are contraindicated owing to their potential for toxicity.
Ertapenem (Invanz)
Bactericidal activity results from inhibition of cell wall synthesis and is mediated through ertapenem binding to penicillin-binding proteins. Stable against hydrolysis by a variety of beta-lactamases, including penicillinases, cephalosporinases, and extended-spectrum beta-lactamases. Hydrolyzed by metallo-beta-lactamases.
Ceftriaxone
Ceftriaxone is a third-generation cephalosporin with broad-spectrum, gram-negative activity. It has lower efficacy against gram-positive organisms and higher efficacy against resistant organisms. Ceftriaxone is used for increasing prevalence of penicillinase-producing microorganisms. It inhibits bacterial cell wall synthesis by binding to 1 or more penicillin-binding proteins. Cell wall autolytic enzymes lyse bacteria, while cell wall assembly is arrested.
Cefotaxime
Cefotaxime is a third-generation cephalosporin that inhibits bacterial cell-wall synthesis. Like other beta-lactam antibiotics, cefotaxime inhibits bacterial growth by arresting bacterial cell wall synthesis. This agent is an alternative drug to ceftriaxone in patients requiring parenteral therapy.
Rifampin (Rifadin)
Inhibits RNA synthesis in bacteria by binding to beta subunit of DNA-dependent RNA polymerase, which in turn blocks RNA transcription. Cross-resistance has only been shown with other rifamycins.
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A patient developed gas gangrene after injecting cocaine. Clostridium septicum was isolated in both blood and wound cultures.
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Gas feathering in the arm soft tissue of a patient with gas gangrene.
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Extension of gas gangrene to the chest wall despite initial debridement.
Tables
Variable |
Score |
|---|---|
C-reactive protein level |
|
< 150 mg/L |
0 |
≥150 mg/L |
4 |
Total WBC count |
|
< 15 cells/µL |
0 |
15-25 cells/µL |
1 |
>25 cells/µL |
2 |
Sodium level |
|
≥135 mmol/L |
0 |
< 135 mmol/L |
2 |
Hemoglobin level |
|
>13.5 g/dL |
0 |
11-13.5 g/dL |
1 |
< 11 g/dL |
2 |
Creatinine level |
|
≤ 141 mmol/L |
0 |
>141 mmol/L |
2 |
Glucose level |
|
≤10 mmol/L |
0 |
>10 mmol/L |
1 |
Variable on Admission |
Points |
||
|---|---|---|---|
Heart rate >110 bpm |
1 |
||
Temperature < 36°C |
1 |
||
Serum creatinine level >1.5 mg/dL |
1 |
||
Age >50 years |
3 |
||
WBC count >40,000/µL |
3 |
||
Hematocrit >50% |
3 |
||
Group category |
Number of points |
Mortality risk (%) |
|
1 |
0-2 |
6 |
|
2 |
3-5 |
24 |
|
3 |
≥6 |
88 |
|
