Associations Between Viral and Bacterial Potential Pathogens in the Nasopharynx of Children With and Without Respiratory Symptoms.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
From the *Second Department of Pediatrics, University of Athens, School of Medicine, and †Microbiology Laboratory, "P & A Kyriakou" Children's Hospital, Athens, Greece.
Chrysanthi L
CL
Skevaki
Paraskevi
P
Tsialta
Aikaterini I
AI
Trochoutsou
Ioanna
I
Logotheti
Heidi
H
Makrinioti
Styliani
S
Taka
Evangelia
E
Lebessi
Irene
I
Paraskakis
Nikolaos G
NG
Papadopoulos
Maria N
MN
Tsolia
D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology / Q000821:virology; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000382:microbiology* / Q000821:virology*; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000382:microbiology / Q000821:virology