Nasopharyngeal (NP) bacterial colonization is necessary for subsequent respiratory and/or invasive infection. Our study aimed at comparing NP bacterial colonization rates between children with and without symptoms of an acute viral respiratory tract infection and examining associations between identified microorganisms.
Children 3 months to 6 years of age with and without an acute viral respiratory tract infection were recruited, and a questionnaire was filled. NP samples were examined for Streptococcus pneumoniae (SP), Haemophilus influenzae (HI), Moraxella catarrhalis (MC), Staphylococcus aureus and Streptococcus pyogenes by culture. Viruses were detected with polymerase chain reaction.
Median age of the 386 recruited children was 23.4 months, and 127 had no respiratory symptoms. More asymptomatic subjects were found negative for all bacteria tested (P < 0.01). SP (P < 0.01), MC (P = 0.001) and mixed bacterial colonization patterns were more frequent among symptomatic children (P < 0.05). Colonization of symptomatic, virus-positive children with MC was higher than in asymptomatic and/or virus-negative children (P = 0.005). The highest HI and MC colonization rates were recorded in association with influenza virus. A strongly negative association between SP and S. aureus, a higher rate of HI detection among SP colonized children and an increased likelihood of MC detection in the presence of HI were observed. HI colonization was more likely in the presence of respiratory syncytial virus and MC colonization was associated with rhinovirus detection.
Viruses are associated with different NP bacterial colonization patterns. Observed pathogens’ associations may play a role in disease, and continuous surveillance is required to follow possible effects of interventions such as vaccines.
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From the *Second Department of Pediatrics, University of Athens, School of Medicine, and †Microbiology Laboratory, “P & A Kyriakou” Children’s Hospital, Athens, Greece.
Accepted for publication August 4, 2015.
C.L.S., S.T. and M.N.T. are members of PreDicta Consortium. M.T. has received honoraria for participation in Advisory Boards of Novartis and AbbVie. She has also received honoraria for presentations in sponsored symposia by GSK and Sanofi Pasteur and has attended scientific meetings sponsored by Novartis, Pfizer and Sanofi Pasteur. The other authors have no other funding or conflicts of interest to disclose. The study was funded by an ESPID Small Grant award to Paraskevi Tsialta, by an unrestricted grant from Pfizer Hellas as an Investigator-initiated study and by the European Commission’s Seventh Framework program under grant agreement no. 260895 (PREDICTA). The other authors have no relevant conflicts to disclose.
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Address for correspondence: Maria N. Tsolia, MD, PhD, Second Department of Pediatrics, University of Athens, School of Medicine, “P & A Kyriakou” Children’s Hospital, Thivon and Levadeias St, 11527 Athens, Greece. E-mail: email@example.com.