Role of viral and bacterial pathogens in causing pneumonia among Western Australian children: a case–control study protocol

Bhuiyan, Mejbah Uddin; Snelling, Thomas L; West, Rachel; Lang, Jurissa; Rahman, Tasmina; Borland, Meredith L; Thornton, Ruth; Kirkham, Lea-Ann; Sikazwe, Chisha; Martin, Andrew C; Richmond, Peter C; Smith, David W; Jaffe, Adam; Blyth, Christopher C

Prior to the introduction of pneumococcal conjugate vaccines in developed countries in the early 2000s, Streptococcus pneumoniae (the pneumococcus) was the leading bacterial pathogen causing CAP, identified in 8-36% of young children with CAP [21] . Other bacteria associated with childhood pneumonia include both encapsulated and nontypeable Haemophilus influenzae, Streptococcus pyogenes, Staphylococcus aureus, and Moraxella catarrhalis [20] . Gram-negative enteric bacteria and atypical intracellular bacteria, for example, Mycoplasma pneumoniae and Chlamydophila pneumoniae have also been reported to cause childhood CAP [20, 22] . M. pneumoniae appears to be detected more commonly among school-aged than in younger children [23, 24] . The burden of bacterial pneumonia has reduced significantly in Europe, the United States and Australia since the introduction of both the conjugate Haemophilus influenzae B and multivalent pneumococcal conjugate vaccines (PCV) into the routine immunization schedule [5, [25] [26] [27] [28] . However, bacteria still remain as important causes of pneumonia in many developing settings where the vaccines have not been introduced or recently introduced [29, 30] .