Pathogens Causing Respiratory Tract Infections in Children Less Than 5 Years of Age in Senegal

Knobbe, Rebecca B; Diallo, Abdallah; Fall, Amary; Gueye, Aida D; Dieng, Assane; van Immerzeel, Tabitha D; Ba, Abou; Diop, Amadou; Diop, Abdoulaye; Niang, Mbayame; Boye, Cheikh SB

Dieng et al studied pathogens in children with ARTI in Senegal and found a total of 78 bacteria in 162 children. They found a lower prevalence of S pneumoniae (18% of cases) in comparison with our study (48% of cases) and a prevalence of M cattharalis of 15% where we did not detect this pathogen. Dieng et al used different swab sampling techniques (bronchoalveolar lavage, sinus fluids, and throat swab) depending on the site of infection. Moraxella cattharalis causes otitis media and sinusitis rather than LRTI, possibly explaining the higher detection rate. 30 Furthermore, their study covered a full year, including all seasons. Although our study was conducted during 2 months, it covered the rainy season, which is known for its respiratory infections. 15 Streptococcus pneumoniae was the most prevalent bacteria in our sample. Recent case-control studies in low-income countries found similar prevalence in cases and controls, even though those countries have lower vaccination coverages. 19, 21, 24, 31 In Western countries with a similar vaccination coverage to Senegal, S pneumoniae rates in children with ARTI are evidently lower than we detected. 32 Possibly, disease burden of S pneumoniae is high in Senegal due to serotype replacement following the introduction of the pneumococcal vaccine, as has occurred in many other countries. 33 Staphylococcus aureus is a bacteria frequently detected in these studies. 19, 21, 24 They used nasal/nasopharyngeal swabs, but the literature does not mention major differences in detection of S aureus between nose or throat. 34 Another explanation is the use of PCR for detection of bacteria.