Back to TAM (Treatments and Medicines) NHS Highland home NHS Highland

Spontaneous Bacterial Peritonitis (SBP) (Antimicrobial)


For glossary of terms see Glossary.

The diagnosis of SPB is based on ascitic fluid neutrophil count >250 cells/mmor >0.25 x109/L.  Ascitic fluid should be sent for culture and blood cultures performed at the same time, before starting antibiotics, in patients admitted to hospital.

Avoid nephrotoxic antibiotics such as aminoglycosides as empiric therapy.

If no improvement is seen within 48 hours, consider contacting Microbiology for escalation advice.

In all patients with suspected SBP, proton pump inhibitors should only be prescribed for a clear indication.

Patients currently prescribed rifaximin do not require a second antibiotic for primary prophylaxis of SBP in the absence of a GI bleed.

Before prescribing ciprofloxacin, see warnings in the BNF and MHRA Drug Safety Update from December 2020 and which details new and previously published risks with all fluoroquinolones.

Drug details

Community-acquired infection, suitable for out-patient treatment

Oral co-amoxiclav 625mg three times daily

5 to 7 days

If penicillin allergy

Oral ciprofloxacin 750mg twice daily

See BNF warnings and MHRA Drug Safety Alert

5 to 7 days

Community-acquired infection requiring hospital admission

IV ceftriaxone 2g once daily

5 to 7 days

Contact Microbiology if known beta-lactam anaphylaxis

If more than 2 courses of antibiotic treatment have been prescribed in the last 2 months (for any indication)

IV piperacillin/tazobactam 4·5g every 6 hours (3 hour infusion time per dose if in critical care)

5 to 7 days

In penicillin allergy

IV aztreonam 2g every 6 hours

PLUS IV Vancomycin as per NHS Highland vancomycin policy

5 to 7 days

If known previous ESBL infection (check SCI Store)

IV meropenem 1g every 8 hours

5 to 7 days

In patients with previous multiple courses of antibiotics, consider fungal pathogens.  Contact Microbiology for advice

Switch to targeted therapy based on positive cultures.  Review IV therapy daily and consider IV to oral switch with clinical improvement.

For primary prophylaxis in patients with cirrhosis and low ascitic protein content of less than 10g/l

Oral co-trimoxazole 480mg once daily

12 months

If hyperkalaemia develops or on concurrent spirololactone

Oral ciprofloxacin 500mg once daily

See BNF warnings and MHRA Drug Safety Alert

12 months

Additional antibiotic prophylaxis is not required for patients on rifaximin.  

Prophylaxis should be stopped in patients with lasting clinical improvement and disappearance of ascites.

For primary prophylaxis following upper GI bleed in presence of cirrhosis

Switch from IV to oral once oral route established

If Nil by Mouth

IV ciprofloxacin 400mg every 8 hours

OR oral ciprofloxacin 750mg twice daily

See BNF warnings and MHRA Drug Safety Alert

5 days total (IV + oral)

For secondary prophylaxis after episode of SBP

Oral ciprofloxacin 500mg once daily

See BNF warnings and MHRA Drug Safety Alert

Lifelong or until resolution of ascites or successful liver transplant

Last reviewed: 25/08/2022

Next review date: 25/08/2025

Author(s): Antimicrobial Management Team.

Version: 2

Approved By: TAM Subgroup of ADTC

Reviewer name(s): Area Antimicrobial Pharmacist.

Document Id: AMT119