Hospital acquired pneumonia (Antimicrobial)

TAM (Treatments and Medicines) NHS Highland
NHS Highland

See NICE Guideline 250 (updated 2 September 2025)

For pneumonia presenting more than 3 days into hospital admission, it is important to give broad-spectrum antibiotics which are active against Gram-negative organisms in the first instance. In more severe infection, consider cover for Legionella, Staph aureus, both MSSA and MRSA.

Use SIRS criteria for severity assessment. Send a sputum sample for microbiological testing and start antibiotic treatment as soon as possible after establishing a diagnosis of hospital-acquired pneumonia, and within 4 hours of clinical suspicion.

Give oral antibiotics first line if the severity of their condition does not require intravenous antibiotics.  Review ongoing need for intravenous antibiotics at 48 hours and switch to oral using positive microbiology results (if available) or options for non-severe infection as per table below.

For glossary of terms see Glossary.

Drug details

Non severe

Co-trimoxazole (oral) 960mg twice daily (reduce dose to 480mg twice daily in renal impairment CrCl 30ml/min or less)
OR Doxycycline (oral) 100mg twice daily

Review at 5 days and stop if clinically stable

 

Severe

Note: infection with an atypical pathogen is uncommon. If suspected, discuss with Microbiology.

Co-trimoxazole (oral or IV) 960mg twice daily

If recent course of co-trimoxazole or unsuitable:

Levofloxacin (oral unless nil by mouth, same dose by IV route) 500mg twice daily (see BNF warnings and MHRA Drug Safety Alert)

Review at 5 days and stop if clinically stable

Editorial Information

Last reviewed: 10/09/2026

Next review date: 10/09/2029

Author(s): Antimicrobial Management Team.

Version: 4

Approved By: TAM Subgroup of ADTC

Reviewer name(s): A MacDonald, Area Antimicrobial Pharmacist.

Document Id: AMT160