Children presenting with empyema or pleural effusion, confluentdense consolidation or pneumatocoele on CXR associated with high-grade pyrexia and elevation of acute phase reactants (e.g. CRP), orthose with features of suppurative lung disease, are highly likely to havea bacterial cause (evidence level Ib).[63,64] The most frequently isolatedbacteria are S. aureus, non-typable H. influenzae, S. pneumoniae andStreptococcus pyogenes (Group A Streptococcus).[63,65]. The gene discussed is CRP; the disease is Pleural effusion.