Pathogens get more complex as you move down the GI tract:
- stomach: streptococcus, lactobacilli
- pancreas (none)
- bile duct: e.coli, klebsiella, enterococcus
- small intestines adds diphtheroids
- distil ileum and colon: bacteroides, clostridium, Enterobacter, E.coli, klebsiella, peptostreptococcus
Community-Acquired Intrabdominal Infection: Appendicitis
Blood/fluid cultures not routinely needed for patients with community-acquired infection unless clinically toxic or high-risk for MDRO infections
Therapy | Pediatric | Adults | |
Mild-Moderate | High | ||
Single Agent | Carbapenems, piperacillin-tazobactam | Cefoxitin, ertapenem, moxifloxacin, tigecycline, or ticarcillin-clavulanic acid |
Carbapenems (not ertapenem) or piperacillin-tazobactam |
Combination | 3rd- or 4th-generation cephalosporins with metronidazole OR aminoglycosides with metronidazole or clindamycin |
1st-, 2nd-, or 3rd-generation cephalosporin, ciprofloxacin, or levofloxacin, each in combination with metronidazole |
Antipseudomonal cephalosporin, ciprofloxacin, or levofloxacin each in combination with metronidazole |
*24 hours of ceftriaxone and metronidazole after surgery for a ruptured appendix
With source control, four days of therapy are usually good enough (STOP-IT Trial).
Healthcare Associated Complicated IAI
Treat according to local resistance factors or micro results.
Organisms seen in healthcare-associated infection at local institution |
Carbapenem | Piperacillin-tazobactam | Ceftazidime or Cefepime Each With Flagyl |
Aminoglycoside | Vancomycin |
---|---|---|---|---|---|
<20% resistant P. aeruginosa, ESBL producing Enterobacteriaceae, Acinetobacter, or other MDR GNB |
Yes | Yes | Yes | No | No |
ESBL-producing Enterobacteriaceae |
Yes | Yes | No | Yes | No |
P. aeruginosa >20% resistant to ceftazidime |
Yes | Yes | No | Yes | No |
MRSA | No | No | No | No | Yes |
Enterococcus: Antimicrobial therapy is recommended when Enterococcus is grown from patients with
healthcare-associated intra-abdominal infections
- Empirical anti-enterococcal therapy: recommended for patients with postoperative infection,
previous use of cephalosporin (or other enterococcus-selecting antibiotics), or valvular heart disease.
Pancreatitis
Typically, no medications are used to treat acute pancreatitis specifically. Therapy is primarily supportive and involves intravenous (IV) fluid hydration, analgesics, antibiotics (in severe pancreatitis), and treatment of metabolic complications (eg, hyperglycemia and hypocalcemia). · Aggressive hydration with lactated ringers is best treatment. TPN can worse pancreatitis. Antibiotics are only recommended in necrotizing pancreatitis or if extrapancreatic infection is present (e.g., cholangitis, bloodstream infection).
For necrotizing pancreatitis, Imipenem 3 × 500 mg/day i.v. for 14 days. Alternatively, Ciprofloxacin 2 × 400 mg/day i.v. PLUS Metronidazole 3 × 500 mg/day for 14 days, These antibiotics penetrate the pancreas.
Acute cholangitis:
- AST/ALT increased, jaundice
- Broad-spectrum gram – and anaerobes
- Enterococcus in hepatic disease and immunocompromised
Diverticulitis:
- Inflammation of diverticulitis in colon. Need CT to get diagnosis.
- Don’t need source control in mild/mod
- Antibiotic coverage: gram – and anaerobes for 10 days
- Low-risk, uncomplicated patients may not need antibiotics.
Infectious Diarrhea
- Don’t treat “non”s: non-typhoid salmonella, non-vibrio cholera
- Campylobacter – azithromycin/cipro
- Salmonella enterica, typhi, paratyphoid – ceftriaxone/cipro
- Shigella – azithromycin, cipro, ceftriaxone
- Vibrio cholera – doxycycline (cipro if ALT)
- Yersinia enterocolitis – Bactrim
- Shiga toxic producing E.coli: leading cause of hemolytic uremic syndrome in kids (anemia, thrombocytopenia, acute kidney injury). DO NOT TREAT. Also called 0157 E.coli or STEC E.coli.
- Fecal leukocyte count and stool lactoferrin should not be used to determine who to treat
- Oral zinc can be used to reduce duration in children 6 months to 5 years in countries with zinc deficiency.