The Center For Disease Dynamics, Economics & Policy

Complicated Intra-Abdominal Infections (cIAI)

Clinical definition:

Intramural inflammation of the gastrointestinal tract extending into the peritoneal space.

 

Preferred antibiotic choice(s)
Drug Formulation Dosage Duration
If mild to moderate: 4 days if source control has been achieved and clinical condition is improving. If not, duration will depend on clinical and radiological progress, jointly managed with surgeons.
Amoxicillin + clavulanic acid (IV/PO) Powder for injection: 500 mg (as sodium) + 100 mg (as potassium salt); 1000 mg (as sodium) + 200 mg (as potassium salt) in vial; Oral liquid: 125 mg amoxicillin + 31.25 mg clavulanic acid/5 mL AND 250 mg amoxicillin + 62.5 mg clavulanic acid/5 mL; Tablet: 500 mg (as trihydrate) + 125 mg (as potassium salt) 875 mg of amoxicillin component 8 hourly
If severe:
Combination therapy with:

Cefotaxime (IV)

PLUS

Metronidazole (IV)

Cefotaxime- Powder for injection: 250 mg per vial (as sodium salt 2 g 8 hourly
Metronidazole- Injection: 500 mg in 100- mL vial 500 mg 6 hourly
Combination therapy with:

Ampicillin (IV)

PLUS

Gentamicin (IV)

PLUS

Metronidazole (IV)

Ampicillin- Powder for injection: 500 mg; 1 g (as sodium salt) in vial 200 mg/kg 4 hourly
Gentamicin- Injection: 10 mg; 40 mg (as sulfate)/ mL in 2- mL vial. 1 mg/kg 8 hourly
Metronidazole- Injection: 500 mg in 100- mL vial 500 mg 6 hourly
If hospital-acquired in a facility where resistance has been documented, consider:
Piperacillin-tazobactam Powder for injection: 2 g (as sodium salt) + 250 mg (as sodium salt); 4 g (as sodium salt) + 500 mg (as sodium salt) in vial 4.5 g 6 hourly 4 days if source control has been achieved and clinical condition is improving. If not, duration will depend on clinical and radiological progress, jointly managed with surgeons.
Alternative antibiotic choice
Meropenem Powder for injection: 500 mg (as trihydrate); 1 g (as trihydrate) in vial 1 g 8 hourly 4 days if source control has been achieved and clinical condition is improving. If not, duration will depend on clinical and radiological progress, jointly managed with surgeons.
In case of confirmed penicillin allergy or medical contraindication
Combination therapy with:

Clindamycin (IV)

PLUS

Gentamicin (IV)

OR

Ciprofloxacin (IV)

Clindamycin- Injection: 150 mg (as phosphate)/mL 20 mg/kg/day divided every 6 to 8 hours 4 days if source control has been achieved and clinical condition is improving. If not, duration will depend on clinical and radiological progress, jointly managed with surgeons.
Gentamicin- Injection: 10 mg; 40 mg (as sulfate)/ mL in 2- mL vial. 1 mg/kg 8 hourly
Ciprofloxacin- Solution for IV infusion: 2 mg/ mL (as hyclate) 500 mg 12 hourly

 

Principles of Stewardship:

  • Obtain a blood culture prior to starting any new antibiotic therapy.
  • Breach of the gastrointestinal tract mucosa is a risk factor for candida infection, which should be considered if source control and antibiotic treatment are not inducing a response.
  • Investigate for TB in endemic areas.

Notes:

  • cIAI is often a difficult infection to treat and requires close collaboration with surgical colleagues to manage, as source control is a key aspect of management.