Recommended Empiric Antibiotic Therapy for Abdominal Infections

First Things First (assess & treat for the following)

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History and Physical (assess for the following):

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Diagnostic Tests

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General Management Principles

  • This section is intended to provide recommendations for empiric (initial) parenteral antibiotic choices for infections seen in immunocompetent, critically ill adult pts.
  • Subsequent antibiotic choices should be guided by Gram stain & culture results.
  • This section is not intended for use in the mgt of AIDS pts.
  • Use local antimicrobial resistance patterns & other specific clinical circumstances (eg, underlying medical problems, acuity of illness, age, setting) to guide empiric antibiotic choices.
  • Drug doses assume normal renal function.
  • Other empiric strategies exist. More detailed information regarding antibiotic selection can be found in multiple sources.
  • Many of these recommendations represent the opinions of the authors.

Specific Treatment

  • Offending microorganisms are usually normal aerobic & anaerobic flora of the GI tract.
  • Empiric antibiotic therapy is aimed at a mixed population of organisms.

Cholecystitis

  • Surgical consultation is mandatory.
  • Cholecystectomy remains the treatment of choice.
  • External drainage is an alternative for pts too unstable to undergo surgery.
  • Timing of surgery is individualized.
  • Empiric therapy: cholecystitis
    • Piperacillin-tazobactam: 4.5 g IV q8h
    • Imipenem-cilastatin: 500 mg IV q6-12h
    • Ampicillin-sulbactam: 1.5-3.0 g IV q6h

Acute acalculous cholecystitis

  • Risk factors include mechanical ventilation, SIRS/sepsis, multiple transfusions, dehydration, TPN, major non-biliary surgery, diabetes mellitus, trauma, burn injury.
  • Should remain in the differential diagnosis of any critically ill pt who experiences sepsis w/out a known source of infection
  • Mortality rate is high, particularly if diagnosis is delayed.
  • Cholecystectomy remains the treatment of choice.
  • External drainage is an alternative for pts too unstable to undergo surgery.
  • Empiric therapy: acute acalculous cholecystitis
    • Piperacillin-tazobactam: 4.5 g IV q8h + an aminoglycoside
    • Imipenem-cilastatin: 500 mg IV q6h + an aminoglycoside

Acute cholangitis

  • Caused by a bacterial infection within partially or totally obstructed biliary ducts
  • Biliary decompression & broad-spectrum antibiotics are the mainstays of therapy.
  • Gastroenterology or surgical consultation is imperative.
  • Empiric therapy: acute cholangitis
    • Piperacillin-tazobactam: 4.5 g IV q8h
    • Imipenem-cilastatin: 500 mg IV q6h

Infected acute pancreatitis

  • The diagnosis of superimposed infection associated w/ acute pancreatitis can be difficult.
  • Diagnosis based upon clinical & radiographic evidence
  • CT-guided fine-needle aspiration is highly sensitive & specific.
  • Surgical consultation & mgt is imperative.
  • Common pathogens include Enterobacteriaceae, enterococci, S. aureus, S. epidermidis, anaerobes & Candida spp.
  • Empiric therapy: infected acute pancreatitis
    • Imipenem-cilastatin: 500 mg IV q6h
    • Piperacillin-tazobactam: 4.5 g IV q8h

Intra-abdominal abscess

  • Drainage & empiric broad-spectrum antibiotics are essential.
  • Antimicrobial therapy should be directed towards common GI flora.
  • Monotherapy is not recommended for severe or hospital-acquired infections.
  • Consider Pseudomonas spp., enterococci & resistant gram-negative rods in the setting of prolonged hospitalization. Add yeasts to this list when persistent generalized peritonitis (uncontained persistent infection) develops.
  • Surgical consultation mandatory. However, percutaneous drainage (interventional radiology) may be adequate.
  • Empiric therapy: intra-abdominal abscess
  • Consider adding an aminoglycoside for hospital-acquired infections:
    • Piperacillin-tazobactam: 4.5 g IV qh8
    • Ampicillin-sulbactam: 3 g IV q6h
    • Imipenem-cilastatin: 500 mg IV q6h
    • Ciprofloxacin: 400 mg IV q12h + metronidazole 15 mg/kg IV x 1, then 7.5 mg/kg IV q6h

Peritonitis

  • Causes of primary infectious peritonitis include spontaneous bacterial peritonitis (SBP), infections caused by peritoneal dialysis catheters, TB & other granulomatous peritonitis. Primary peritonitis usually responds to medical therapy.
  • Secondary infectious peritonitis is a localized (abscess) or diffuse infectious process resulting from a defect (spontaneous, post-traumatic or postop) in an abdominal viscus. Timely surgical intervention is imperative.
  • Tertiary peritonitis is a peritonitis-like syndrome due to an altered immune response by the host (peritonitis w/out pathogens, peritonitis w/ fungi, peritonitis w/ low-grade bacteria).
    • Empiric therapy for spontaneous bacterial peritonitis
      • Cefotaxime: 2 g IV q8h
      • Ceftriaxone: 1-2 g IV q24h
      • Imipenem-cilastatin: 500 mg IV q6h
      • Ciprofloxacin: 400 mg IV q12h
  • Empiric therapy for secondary peritonitis
  • Consider adding an aminoglycoside for hospital-acquired infections.
    • Piperacillin-tazobactam: 4.5 g IV qh8
    • Ampicillin-sulbactam: 3 g IV q6h
    • Imipenem-cilastatin: 500 mg IV q6h
    • Ciprofloxacin: 400 mg IV q12h + metronidazole: 15 mg/kg IV x 1, then 7.5 mg/kg IV q6h

Diverticulitis

  • Surgical consultation advised.
  • Indications for emergent surgical intervention in immunocompetent pts include generalized peritonitis, uncontrolled sepsis, visceral perforation, obstruction & acute clinical deterioration.
  • Empiric inpatient therapy: diverticulitis
    • Piperacillin-tazobactam: 4.5 g IV q8h
    • Ampicillin-sulbactam: 3.0 g IV q6h
    • Ciprofloxacin: 400 mg IV q12h + metronidazole: 15 mg/kg IV x 1, then 7.5 mg/kg IV q6h
    • Imipenem-cilastatin: 500 mg IV q6h

Peptic ulcer disease (H. pylori)

  • NIH recommends testing & treating all pts w/ symptomatic peptic ulcer disease.
  • Therapy: peptic ulcer disease
    • Proton pump inhibitor + clarithromycin 500 mg PO bid + amoxicillin 1 g PO bid
    • Alternate 3-drug & 4-drug strategies exist.

Acute community-acquired diarrhea

  • Causes of acute community-acquired diarrhea include bacteria and/or their toxins, viruses & parasites.
  • Most cases are treated w/ supportive care only.
  • Empiric antibiotic therapy for community-acquired diarrhea must be carefully weighed against its potentially harmful consequences:
  • Diarrhea caused by C. difficile can be seen in outpatients who have recently taken antibiotics.
  • Circumstances where empiric antibiotic therapy is considered include:
    • Traveler’s diarrhea
    • Moderate to severe, febrile diarrheal illnesses
  • Empiric therapy: community-acquired diarrhea
    • Ciprofloxacin: 500 mg PO bid x 3-5 days
    • Trimethoprim/sulfamethoxazole: 1 DS tab PO bid x 5 days
      • See Nosocomial Diarrhea for toxigenic C. difficile treatment recommendations.

Nosocomial diarrhea

  • Causes of nosocomial diarrhea include antibiotics & other drugs, enteral feeding, infection & GI bleeding or ischemia.
  • Nearly all cases of infectious diarrhea in the ICU are caused by C. difficile.
  • Only rarely do community-acquired infections (eg, Salmonella, Shigella, Campylobacter, others) cause diarrhea in pts after they have been admitted for several days to an ICU.
  • Repeat C. difficile assays are usually obtained because their sensitivity is incomplete.
    • Therapy: C. difficile enterocolitis
      • Metronidazole: 500 po qid
      • Vancomycin: 125-250 mg PO q12h
      • Metronidazole: 500 mg IV q8h (least preferred)

Ongoing Assessment

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Complications

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Author

  • Robert O’Connell, MD & Steven A. Venticinque, MD

Recommended Empiric Antibiotic Therapy for Abdominal Infections is a sample topic from the Pocket ICU Management.

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Last updated: April 23, 2010

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TY - ELEC T1 - Recommended Empiric Antibiotic Therapy for Abdominal Infections ID - 534176 Y1 - 2010/04/23/ PB - Pocket ICU Management UR - https://anesth.unboundmedicine.com/anesthesia/view/Pocket-ICU-Management/534176/all/Recommended_Empiric_Antibiotic_Therapy_for_Abdominal_Infections ER -