Kingella kingae occult bacteremia in a toddler.

Abstract

To The Editors: Kingella kingae has been recognized with increasing frequency as a pathogen of invasive infections in early childhood.1 It causes septic arthritis, osteomyelitis, endocarditis and other focal infections,1-4 but only a few patients with occult bacteremia have been described.1-5 Some authors advocate active search for an endocardial focus whenever K. kingae is isolated in blood culture.6 Yagupsky et al.5 reported seven children with K. kingae occult bacteremia without endocarditis and pointed out that all bacteremic children in their series and in previous studies were younger than age 12 months. It was suggested that the symptoms related to K. kingae bacteremia are age-dependent; i.e. older children are not symptomatic. Recently we treated in our hospital a 2-year, 8-month-old girl who had K. kingae bacteremia. This previously healthy girl had a fever (39.3°C), vomiting and watery diarrhea for 2 days. No other family members were affected and there was no history of travel. The patient was in good general condition. Small ulcers were noted on the buccal mucosa. There were no signs of arthritis, osteomyelitis or endocarditis. The white blood cell count was 9500/mm3 with 60% neutrophils. Blood culture obtained at admission, inoculated into aerobic culture medium (Becton Dickinson), yielded K. kingae, which was susceptible to penicillin, cephalosporins and aminoglycosides. K. kingae was identified on the basis of a typical Gram-stained smear, beta-hemolysis, positive oxidase reaction, negative catalase and urease and fermentation of glucose and maltose. The patient was treated with cefuroxime for 10 days. The symptoms subsided within 24 h and subsequent blood cultures showed no growth. Echocardiographic examination was normal. Our patient presented with fever, diarrhea and aphtous stomatitis, features previously found in association with K. kingae bacteremia.5 To our knowledge K. kingae occult bacteremia has not yet been reported in children older than 12 months. The rarity of K. kingae occult bacteremia in children older than 12 months might be explained by several factors: (1) milder symptoms in older children; (2) blood cultures obtained more frequently in febrile infants under the age of 12 months; and (3) low awareness of this pathogen and regarding it as contaminant. We think that it is important for pediatricians to be aware of K. kingae as a possible pathogen of occult bacteremia in infants and young children. Irit Krause, M.D.; Revital Nimri, M.D. Schneider Children's Medical Center of Israel Petah-Tiqva, Israel