Respiratory Colonization by Kingella kingae, Person-to-Person Transmission, and Pathogenesis of Invasive Infection

Abstract

Increasing recognition of Kingella kingae as an important pathogen of early childhood in recent years has elicited interest in the study of the asymptomatic carriage of the organism, its dissemination in the human population, and the role played by colonization of the upper respiratory tract in the pathogenesis of K. kingae invasion of the skeletal system and the endocardium.Research has revealed that K. kingae is a frequent component of the normal oropharyngeal microbiota, disclosed the subtle molecular mechanisms responsible for adherence of the bacterium to the pharyngeal mucosa, and revealed the presence of a potent RTX toxin, probably implicated in breaching the epithelial barrier, survival of the organism in the bloodstream, and damage to bone and joint tissues. Epidemiological studies have shown that carriage of K. kingae peaks in 6-30 month-old children, coinciding with the age of increased susceptibility to invasive disease, and daycare-center attendance represent a significant risk factor for pharyngeal colonization. The organism is transmitted from person-toperson by close contact between family members, playmaytes, and day-care center attendees. Carriage is characterized by frequent turnover of colonizing strains, similar to what has been described in other pathogens of respiratory origin.

Phasevarion-Regulated Virulence in the Emerging Pediatric Pathogen Kingella kingae

“…However, unlike other HACEK organisms, K. kingae-mediated infective endocarditis can progress very rapidly (4-6) and is associated with serious complications, with an overall mortality rate of 16% (1, 6). Adults with invasive infections usually have predisposing medical ailments.Transmission occurs via close personal contact, and clusters of invasive infections have been reported among day care center attendees (7,8). Invasive disease begins with colonization of the oropharynx and is often preceded by an upper respiratory tract infection (8, 9).…”

“…Transmission occurs via close personal contact, and clusters of invasive infections have been reported among day care center attendees (7,8). Invasive disease begins with colonization of the oropharynx and is often preceded by an upper respiratory tract infection (8, 9).…”

“…Invasive disease begins with colonization of the oropharynx and is often preceded by an upper respiratory tract infection (8,9). The disrupted respiratory mucosa may then facilitate invasion and hematogenous dissemination to the bones, joints, and heart (10).…”

A Prospective Study of Intrafamilial Oropharyngeal Transmission of Kingella Kingae

“…2,4,5 There is, to the best of our knowledge, only 1 prospective study in the English literature which suggests an intrafamilial oropharyngeal transmission of K. kingae between Bedouins siblings. 8 Our results show that almost 55% of children with OAI due to K. kingae have siblings who are either asymptomatic or symptomatic carriers of a K. kingae strain. Considering all children together, the risk for a sibling of a K. kingae carrier to have a positive oropharyngeal K.kingae PCR is of 40%.…”

“…Child-to-child transmission of K. kingae has been described by many authors, 7,8 as well as the fact that 50% of children carry this microorganism for long periods. 1 Possible mechanisms of transmission of K. kingae include saliva and dissemination of upper respiratory secretions from children suffering from viral infections and daycare center attendance represents a major trasmission risk factor.…”