• consider antibiotic therapy duration dependent on adequacy of drainage and on clinical response, typically 2-4 weeks.
• at discharge, give oral antibiotics for 1-4 weeks, or longer in cases of residual disease.

Ref:

• Balfour-Lynn IM, Abrahamson E, Cohen G, et al; Paediatric Pleural Diseases Subcommittee of the BTS Standards of Care Committee. BTS guidelines for the management of pleural infection in children. Thorax, 2005 Feb;60 Suppl 1:11-21full-text, editorial can be found in Thorax 2005 Feb; 60(2):94.
• Bradley JS, Byington CL, Shah SS, et al. The management of community-acquired pneumonia in infants and children older than 3 months of age: clinical practice guidelines by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America. Clin Infect Dis. 2011 Oct;53(7):e25-76, commentary can be found in Clin Infect Dis 2012 Jun;54(12):1816.