Johns Hopkins Antibiotic (ABX) Guide

Intra-abdominal Abscess

PATHOGENS

  • If identified, location of source of infection (e.g., site of perforation - stomach, duodenum, jejunum, ileum, appendix or colon) defines likely flora.
  • Health-care associated flora more likely when infections are complications of prior intraabdominal operations or procedures.

CLINICAL[Top]

  • Broad range of presenting complaints:
    • Patients may only present with malaise/anorexia or weight loss.
    • Others present acutely ill in septic shock with an acute abdomen.
  • Non visceral abscesses develop after gastrointestinal perforation from local disease (diverticulitis, etc.), trauma, or surgical intervention.
    • Subsequent secondary peritonitis then becomes walled off by inflammatory adhesions, loops of intestine, mesentery or omentum, and other abdominal viscera
    • Intraabdominal abscess also may develop after primary peritonitis (spontaneous bacterial peritonitis).
  • History: fever, pain, nausea, vomiting, anorexia, abdominal pain.
  • PE: local tenderness, possibly a palpable mass; if postoperative, assessment for abscess confounded by analgesics, ileus and incisional pain; over half presenting within 10 days of initial operation.
  • Lab: elevated WBC, direct aspiration yielding positive Gram stain/culture, blood cultures positive ~25% depending on site and severity.
    • Laboratory analysis may also reveal derangements in liver enzymes, elevated alkaline phosphatase or hypergammaglobulinemia depending on duration and location of the abscess (e.g., liver, gallbladder, etc.).

DIAGNOSIS[Top]

  • CT most helpful. US and MRI used occasionally. MRI not used for drainage guidance.
  • CT- or US-guided percutaneous or surgical drainage should be considered in all cases for diagnostic confirmation, microbiologic evaluation, and therapy.
  • Indium and gallium scanning rarely required for this diagnosis with the advent of these imaging newer modalities.
  • Where feasible, percutaneous drainage of well-localized fluid collections is preferable to surgical drainage for diagnostic and therapeutic purposes.

TREATMENT[Top]

Primary therapy: abscess drainage

  • CT or US-guided percutaneous needle aspiration with subsequent catheter drainage is considered by many as the first line of therapy; if drainage is inadequate surgery may be required.
    • Surgery used primarily after percutaneous therapy has failed, after percutaneous therapy has stabilized the condition in preparation for primary surgical therapy, or when concurrent surgical source control needed.
    • Infected pancreatic necrosis not well suited to percutaneous therapy because of cellular debris.
  • If an abscess unrelated to a surgical procedure is encountered, must consider the possibility of an underlying necrotic cancer.
  • Antimicrobial therapy alone (without drainage or a surgical procedure) should be reserved for highly-selected patients with a relatively small, well-circumscribed area of infection and minimal physiological derangement, provided close monitoring and follow-up can be arranged.

Adjunctive antibiotic treatment

  • Empiric coverage (i.e., when the microbiologic source of infection is unknown) should include coverage of Enterobacteriaceae, enteric Streptococci, and anaerobes.
    • Empirical coverage of Enterococci should be considered in hospital-acquired and healthcare-associated infections
    • Empiric coverage may be broadened or cautiously narrowed on the basis of the abscess and blood culture results.
  • Mild-moderate infection (preferred):
  • Severe and/or nosocomial infections (preferred):
  • Duration: after adequate drainage, at least 4-7 days of antibiotic coverage is indicated, with duration in part based on resolution of fever and leukocytosis, severity of infection, and additional indicators of clinical response.
    • Duration of therapy has not been subjected to rigorous study.
    • If the underlying surgical problem or source has been difficult to control a longer course of antibiotics maybe appropriate.
    • Duration of antibiotic therapy for an inadequately drained abscess with residual fluid may require prolonged therapy with follow-up imaging to ensure resolution, but sufficient data is lacking to fully support this approach.

Selected Drug Comments

Drug

Recommendation

Ampicillin/sulbactam

Increased rates of resistance makes this a suboptimal choice for empiric therapy. Historically good coverage of gram-positive, gram-negative, and anaerobic pathogens - lacks Pseudomonas aeruginosa and has diminished Enterobacteriaceae susceptibilities but good Enterococcus species coverage.

Piperacillin/tazobactam

Excellent broad spectrum coverage including gram-positive coverage, gram-negative coverage (including Pseudomonas aeruginosa and beta-lactamase producing pathogens) and anaerobic coverage.

Ertapenem

Good broad spectrum coverage including ESBL gram-negatives and anaerobes, but doesn’t provide coverage for Pseudomonas aeruginosa. Also no enterococcal coverage unlike imipenem.

Cefepime

Excellent coverage of gram-negative and gram-positive pathogens; use in combination with anaerobic agent (plus/minus an agent covering Enterococcus species) for empiric therapy.

Moxifloxacin

Excellent broad spectrum coverage including gram-negatives and most anaerobes, but does not provide coverage for P. aeruginosa. Due to increasing Bacteroides resistance would only use for mild infections.

Ticarcillin/clavulanic acid

Historically excellent broad spectrum coverage including gram-positive coverage, gram-negative coverage (including Pseudomonas aeruginosa and B-lactamase producing pathogens) and anaerobic coverage. Due to rising rates of Gram negative resistance, would only use for mild-moderate infections empirically.

Tigecycline

Newer agent with very broad coverage (gram-positive including MRSA and VRE, gram-negatives including Acinetobacter spp. but not P. aeruginosa or Proteus sp). Good choice in patients with high grade beta lactam allergy. Recent pooled analysis of clinical trials revealed an increased mortality risk compared with other antibiotics used to treat a variety of infections, including IAIs.

Metronidazole

Offers excellent anaerobic coverage, should be used in combination with an agent covering GNRs and possibly Enterococcus species.

Imipenem/cilastatin

Excellent broad spectrum (gram-positive, gram-negative, and anaerobe) coverage; would reserve for seriously ill patients at high risk for resistant pathogens.

Meropenem

Excellent broad spectrum (gram-positive, gram-negative, and anaerobe) coverage; would reserve for seriously ill patients at high risk for resistant pathogens.

Doripenem

Newer carbapenem, approved for complicated intra-abdominal infections in 2007. Excellent broad spectrum (gram-positive, gram-negative, including some carbapenem-resistant Pseudomonas species, and anaerobe) coverage, would reserve for seriously ill patients at high risk for resistant pathogens.

Ceftriaxone

Very good gram-negative coverage and gram-positive coverage; use in combination with anaerobic agent (plus/minus an agent covering Enterococcus species) for empiric therapy

FOLLOW UP[Top]

  • Source control is essential. The open abdomen approach is occasionally necessary in severe infections.
  • On-demand re-laparotomy rather than a planned re-laparotomy may be associated with better results in selected cases.
  • If no clinical response within 3-5 days of antibiotic therapy and drainage, consider re-imaging to assess for undrained collections or other processes.
  • Follow up CT scan/US and/or sinograms are often needed to demonstrate resolution of source and abscess.
  • Useful clinical parameters to follow include imaging studies, temperature, white blood cell count and possibly serum C-reactive protein.
  • In select patients with spontaneous abscess from Crohn’s disease, reinstitution or optimization of immunosuppressants therapy may be appropriate after percutaneous drainage.

OTHER INFORMATION[Top]

  • Multiple factors, including severity of illness, bacteremia, multiple abscesses, and location of abscess are predictive of mortality (even with treatment, mortality may still approach 30% depending on the population).
  • Percutaneous drainage should be utilized IF possible and surgical source is controlled.
  • Rate of recovery of yeast from intraoperative specimens of a perforated viscus was >30% and was associated with death and complications. Consider anti-fungal treatment if recovery of yeast from cultures and patient not clinically improving, or repeated recovery of yeast from cultures.
  • Empiric coverage of yeast and enterococci is adults with community-associated intra-abdominal infection is not necessary. Consideration of these organisms are reasonable if clinical response is not as expected.

Pathogen Specific Therapy[Top]

Pathogen

1st Line Agent

2nd Line Agent

Anaerobes

Metronidazole

Piperacillin/tazobactam, ticarcillin/clavulanic acid, ampicillin/sulbactam, imipenem, meropenem, doripenem, tigecycline, clindamycin.

Enterobacteriaceae

3rd generation cephalosporins, fluoroquinolones

Pipercillin/tazobactam, ticarcillin/clavulanic acid, ampicillin/sulbactam, tigecycline, aminoglycosides, carbapenems for resistant pathogens; ampicillin/sulbactam is no longer recommended empirically based on increasing resistance to E. coli.

Enterococci

Penicillin or ampicillin +/- gentamicin

Vancomycin +/- gentamicin, linezolid, daptomycin, tigecycline

Streptococci

Penicillin or ampicillin

Cefazolin, etc.

Pseudomonas aeruginosa

Piperacillin, ceftazidime, cefepime

Imipenem, meropenem, doripenem; ciprofloxacin or levofloxacin (if susceptible)

Candida albicans or other Candida species

Fluconazole
Echinocandins (caspofungin, micafungin, anidulafungin)

Amphotericin B or lipid formulation products,
voriconazole, posaconazole

Staphylococcus aureus

Nafcillin or oxacillin, cefazolin

Vancomycin, linezolid, daptomycin, tigecycline

Coagulase-negative staphylococci

Vancomycin

Linezolid, daptomycin, tigecycline

Basis for recommendation[Top]

  1. Solomkin JS et al: Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America. Clin Infect Dis 50:133, 2010  [PMID:20034345]

    Comment: IDSA, SIS, ASM, and SIDP consensus guidelines

References[Top]

  1. Feagins LA et al: Current strategies in the management of intra-abdominal abscesses in Crohn's disease. Clin Gastroenterol Hepatol 9:842, 2011  [PMID:21679776]

    Comment: Reviews strategies for managing intra-abdominal abscesses in Crohn’s disease; includes a management algorithm and a discussion on immunosuppression management during infection.

  2. Hammond NA, Nikolaidis P, Miller FH: Left lower-quadrant pain: guidelines from the American College of Radiology appropriateness criteria. Am Fam Physician 82:766, 2010  [PMID:20879699]

    Comment: Guidelines for use of imaging modalities for LLQ pain utilizing ACR appropriateness criteria; includes case examples

  3. Kumar RR et al: Factors affecting the successful management of intra-abdominal abscesses with antibiotics and the need for percutaneous drainage. Dis Colon Rectum 49:183, 2006  [PMID:16322960]

    Comment: Retrospective review assessing need for percutaneous drainage vs. antibiotic therapy alone.

  4. Mazuski JE, Solomkin JS: Intra-abdominal infections. Surg Clin North Am 89:421, 2009  [PMID:19281892]

    Comment: Review of management of a variety of intra-abdominal infections.
    Rating: Important

  5. Solomkin JS, Mazuski J: Intra-abdominal sepsis: newer interventional and antimicrobial therapies. Infect Dis Clin North Am 23:593, 2009  [PMID:19665085]

    Comment: Review of use of antibiotics in intra-abdominal infections; precedes guidelines published in 2010 .
    Rating: Important

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