• All patients with CAP should be risk stratified for site of care as outpatients, or inpatients based on scores such as CURB -65/ CRB-65, clinical assessment and pulse oximetry. Further triage for inpatients for ICU/ WARD admission can be based on applying the ATS/ IDSA criteria.
• The choice of antibiotics depends on various factors including severity of disease, presence or absence of co-morbidities, likely pathogen, likely resistance pattern and previous antibiotic use.
• Overall the antibiotic therapy is geared towards covering S. pneumoniae the commonest pathogen in CAP. Several studies have looked at the benefit of including an atypical cover in the regime and the consensus is that atypical cover/ combination therapy is not routinely required in outpatient CAP since the disease is mild, the benefit of treatment for mycoplasma/ Chlamydia is controversial and macrolides may be associated with cardiac abnormalities in the elderly.
• Combination therapy with beta-lactam and macrolide is indicated in outpatient CAP in the presence of co-morbidities or antibiotic use in previous three months and in all inpatient CAP. The rationale for combination therapy in these settings is to expand the spectrum and covering atypical pathogens (especially legionella in severe CAP), immunomodulation and also that combination therapy has been seen to reduce mortality in some studies.
• The role of fluoroquinolones is well established in CAP and all western guidelines where the baseline prevalence of TB is low endorse them. However, in India where there is a high burden of TB and where TB may present as CAP, use of empiric fluoroquinolone therapy may lead to masking and delayed diagnosis of TB and promotion of drug resistance. Therefore, fluoroquinolines are best avoided. Similarly, drugs with anti-tubercular activity including linezolid and aminoglycosides should not be used.
• The empiric addition of oseltamivir should be considered in patients with CAP if there is an ongoing outbreak.  
• The duration of therapy in outpatients is 5 days. Therapy in hospitalized patients with CAP can be switched from parenteral to oral after clinical improvement and is 7 days. Patients can be considered for discharge if they are afebrile, accepting orally and hemodynamically stable for 48 hours. Longer duration of therapy should be considered in patients with bacteremic pneumococcal pneumonia, S. aureus pneumonia, Legionella pneumonia, lung abscess, empyema, pneumonia with enteric gram negative bacilli (Klebsiella) or non fermentative gram negative bacilli (Pseudomonas/ Acinetobacter) or if there is endocarditis/ meningitis complicating pneumonia.
• CAP in children is classified as pneumonia, (age related tachypnea) severe pneumonia (tachypnea and recessions) and very severe pneumonia (severe pneumonia with hypoxemia, dullness or inability to drink). Severe or very severe pneumonia are ideally treated as inpatients. There is some data that severe CAP can also be treated on an outpatient basis in certain situations. No investigations including CXR are needed for outpatients. Blood cultures and CXR should be performed for inpatients. CBC and CRP may not always help differentiate bacterial from viral CAP. Other investigations to determine etiology are not routinely indicated. Empiric antimicrobial therapy is discussed in Table 2.  Salient difference from adult CAP is the selective use of macrolides only if clinical features suggest mycoplasma. Complications such as empyema should be watched out. Duration of therapy for outpatients is 5 days and for uncomplicated pneumonia in inpatients is 7 days.

Table: Choice of empiric antimicrobial therapy in adult CAP

*Chronic heart, liver, renal or lung disease, diabetes mellitus, malignancies, alcoholism or use of immunosuppressive drugs
** Azithromycin/ Clarithromycin
# Chronic respiratory disease (COPD, bronchiectasis, asthma, chronic bronchitis), neurologic disorders, enteral tube feeding and immunocompromised states.
## Preceding influenza, cavitary infiltrates with no underlying aspiration, shock, empyemas