Oropharyngeal Kingella kingae carriage in children: characteristics and correlation with osteoarticular infections

BACKGROUND: The aim of this study was to investigate changes in oropharyngeal K. kingae carriage during the first 4 y of life, including seasonal variation and comparison of asymptomatic carriage with cases of invasive osteoarticular infections (OAI). METHODS: Oropharyngeal bacterial K kingae carriage was screened in 744 healthy children aged 7-48 mo between January 2009 and December 2012. Oropharyngeal swabs were analyzed by rt-PCR targeting the DNA of K kingae RTX toxin, epidemiological characteristics of asymptomatic carriers and OAI case patients were recorded. RESULTS: The carriage prevalence showed no significant difference between age groups or seasons. Compared with asymptomatic carriers, OAI cases were more likely to be aged from 7 to 12 mo (OR = 2.5; 95% CI (1.2-5.0)) and 13-24 mo (OR = 2.2; 95% CI (1.2-3.9)), and less likely over 36 mo (OR = 0.2; 95% CI (0.1-0.7)). Fewer OAI cases were identified in spring compared to asymptomatic carriers (OR = 0.3; 95% CI (0.10.7)), while more were detected in autumn (OR = 2.5; 95% CI (1.4-4.4)). CONCLUSION: Although oropharyngeal K kingae colonization is a prerequisite for further invasive infection, this epidemiological study emphasizes that the carriage rate variations do not correlate with the variations of OAI incidence by gender, season, or age group.