Antibiotics for Abdominal Infections

Tazocin is contraindicated with penicillin allergy so be sure to check first

Simple Gastroenteritis

• Due to Salmonella (non typhoid), Shigella, Campylobacter, E. coli 0157
• Usually self-limiting and antibiotic treatment is not usually recommended.
• In severe cases contact Consultant Microbiologist. NB Notifiable disease

Parasitic infestation

• Giardiasis and amoebiasis - treat according to the causative agent as in BNF
• There is no treatment for diarrhoea due to Cryptosporidium or Microsporidium spp

Viral gastroenteritis

• Norovirus/rota viruses: self-limiting diseases - rehydration is important

Clostridioides difficile colitis

• First line: Metronidazole 400mg tds PO for 10-14 days
• Second line: Vancomycin 125mg qds PO for 10-14 days
• Discuss all concurrent/future antibiotics with Consultant Microbiologist. Patients are at lifelong risk of recurrent infection.

Helicobacter eradication

• Lansoprazole 30mg bd PO + Clarithromycin 500mg bd PO plus Amoxicillin 1g bd PO 7 days
• Penicillin allergy use Metronidazole 400mg bd PO instead of Amoxicillin

Peritonitis and abdominal sepsis

• Likely causes mixed gut flora.
• Tazocin (US Zosyn) 2.25g IV TDS plus stat Gentamicin IV if patient shocked
• Penicillin allergic: Tigecycline 100mg IV initially then 50mg bd IV

Spontaneous bacterial peritonitis (In cirrhosis and ascites)

• Likely causes : coliforms, Strep pneumoniae.
• Tazocin (US Zosyn) 2.25g IV TDS Treat for 10-14 days
• Penicillin allergy contact Consultant Microbiologist.

Liver abscess

• Likely causes: coliforms, streptococci, anaerobes, (Entamoeba histolytica, hydatid.)
• Tazocin 2.25g IV TDS unless Penicillin allergy or parasitic infections
• Discuss with Consultant Microbiologist.
• Length of course dependent on many factors including drainage

Cholecystitis

• Likely causes: coliforms. Treat with Tazocin (US Zosyn) 2.25g IV TDS
• Review after 48 hours, consider switch to Co-Amoxiclav 625mg tds PO
• Penicillin allergy discuss with the Consultant Microbiologist.

Empyema of gall bladder

• As in liver abscess (in addition to surgical drainage)

Ascending cholangitis

• Due to mixed gut flora including coliforms and anaerobes
• Tazocin 4.5g tds IV unless Penicillin allergy then discuss with Microbiologist.
• Treat for 7-10 days

Necrotising pancreatitis

• Likely causes: gut flora
• Antibiotics for severe necrotising disease only.
• No advantage in mild/moderate cases
• Tazocin (US Zosyn) 4.5g tds IV or Meropenem 500mg qds IV
• Treat for up to 2 weeks.
• Penicillin allergy discuss with the Consultant Microbiologist.

Diverticulitis

• Likely causes: gut flora. Treat with Metronidazole 500mg tds IV
• Less severe: Metronidazole 400mg tds po for 5 days for total duration

Cirrhosis with acute GI bleeding (with/without ligation)

• Likely causes: gut flora treat with Tazocin (US Zosyn) 2.25g IV TDS for 5 days
• Penicillin allergy discuss with the Consultant