Medication Summary
Parenteral narrow-spectrum antibiotics should be prescribed according to the organism isolated. If cultures are consistently negative, administer broad-spectrum antibiotics for several weeks.
Antibiotics
Class Summary
Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.
Vancomycin (Lyphocin, Vancocin, Vancoled)
Potent antibiotic that is directed against gram-positive organisms and is active against Enterococcus species. Useful in the treatment of septicemia and skin structure infections. Indicated for patients who cannot receive or have failed to respond to penicillins or cephalosporins or who have infections with resistant staphylococci. For abdominal penetrating injuries, it is combined with an agent active against enteric flora and/or anaerobes.
To avoid toxicity, the current recommendation is to assay vancomycin trough levels after the third dose is drawn and a half an hour prior to the next dose. Use CrCl to adjust the dosage in patients diagnosed with renal impairment.
Used in conjunction with gentamicin for prophylaxis in patients who are allergic to penicillin and are undergoing gastrointestinal or genitourinary procedures.
Nafcillin (Unipen, Nallpen, Nafcil)
Initial therapy for suspected penicillin-G–resistant streptococcal or staphylococcal infections. Use parenteral therapy initially for severe infections. Change to oral therapy as condition warrants.
Due to thrombophlebitis, particularly in the elderly, administer parenterally only for short term (1-2 d); change to oral route as clinically indicated.
Ceftazidime (Tazidime, Tazicef, Ceptaz, Fortaz)
Third-generation cephalosporin with broad-spectrum, gram-negative activity; lower efficacy against gram-positive organisms; higher efficacy against resistant organisms. Arrests bacterial growth by binding to one or more penicillin-binding proteins.
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Axial CT scan in a patient with diskitis demonstrates extensive destruction of the vertebral endplate. Note the preservation of the posterior elements, including facet joints, lamina, and spinous process. This is characteristic for pyogenic diskitis and less common in tuberculosis (Pott disease).
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Sagittal T1-weighted MRI of the lumbar spine in a 74-year-old man, revealing diskitis of the L4-L5 disk space. Note extensive destruction of the endplates of the adjacent vertebral bodies. No compression of the thecal sac is present, which is an important consideration when contemplating surgical intervention.
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Contrast-enhanced sagittal T1-weighted MRI image in a 55-year-old woman shows thoracic diskitis with an associated epidural abscess and spinal cord compression. Because of the significant cord compression, this patient underwent surgical decompression.
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Trajectory of a needle in a biopsy of the infected disk space guided by CT scan. Care is taken to avoid the thecal sac and nerve roots.
