The two guidelines include recommendations on treatment, reassessment, referral and choice of antibiotic.
The guidelines say that antibiotic treatment should be started as soon as possible in both community- and hospital-acquired pneumonia - no more than 4 hours after diagnosis and 1 hour if sepsis is suspected.
For community-acquired pneumonia, the recommended antibiotic options differ according to the severity of infection. In adults, severity should be assessed by clinical judgment guided by mortality risk score as follows:
- low severity - CRB65 score 0 or CURB65 score 0 or 1
- moderate severity - CRB65 score 1 or 2 or CURB65 score 2
- high severity - CRB65 score 3 or 4 or CURB65 score 3 to 5.
The first-choice oral antibiotic for low or moderate severity infection in adults is amoxicillin 500mg three times daily for 5 days. The guidance says amoxicillin has good activity against Streptococcus pneumoniae, the main bacterial cause of pneumonia, and is associated with fewer adverse effects and relatively low resistance rates. In moderate infections, clarithromycin (or in pregnancy, erythromycin) should be added if atypical pathogens are suspected.
For severe infection, co-amoxiclav plus clarithromycin (or in pregnancy, erythromycin) is recommended. This provides broad-spectrum Gram-negative cover and cover for atypical pathogens. The high risk of mortality in this population outweighs the potential adverse effects and increased risk of antimicrobial resistance.
Alternatives to amoxicillin are doxycycline and clarithromycin for infections of low or moderate severity and erythromycin for low-severity infections in pregnancy. NICE says these antibiotics have good activity against S. pneumoniae; however, because of their broader spectrum of activity (and because some also have additional safety warnings), the committee agreed that these antibiotics should be used only when there is a clinical reason not to use amoxicillin.
The alternative antibiotic for adults with high-severity community-acquired pneumonia and penicillin allergy is levofloxacin.
Based on its experience and the risks of antimicrobial resistance with longer courses, the guideline committee agreed by consensus that a 5-day course of recommended antibiotics was appropriate to treat community-acquired pneumonia.
The recommended antibiotic options and dosages for community-acquired pneumonia in adults are summarised in the MIMS table of antibiotic regimens.
The new guidelines are the latest addition to NICE's growing suite of antimicrobial prescribing guidance, which aim to optimise antibiotic use and reduce antibiotic resistance.