Dissemination of kingella kingae in the community and long-term persistence of invasive clones

BACKGROUND: Although Kingella kingae is being increasingly recognized as an important pediatric pathogen, our current understanding of the transmission of the organism is limited. The dissemination of K. kingae in the community was studied in 2 ethnic groups living side-by-side in Southern Israel. METHODS: Organisms recovered from oropharyngeal cultures, obtained from healthy young Jewish and Bedouin children during a 12-month period, were typed by pulsed-field gel electrophoresis and compared. RESULTS: Isolates from Bedouin children usually differed from those derived from Jews, confirming the relative social isolation of the 2 populations and the importance of close mingling in the spread of K. kingae. Significant clustering of genotypic clones in households and Bedouin neighborhoods was observed, indicating person-to-person transmission through intimate contact. Organisms detected in the study were identical to historical isolates recovered over the last 15 years from respiratory carriers and patients with bacteremia or skeletal infections. CONCLUSIONS: The present study demonstrates that children may be asymptomatically colonized in the respiratory tract by virulent K. kingae clones. The organism is transmitted from child-to-child through intimate contact. Some strains exhibit increased fitness and are maintained in the population for prolonged periods.