SHORT REPORT

Pablo Yagupsky Æ Joseph Press

Unsuspected Kingella kingae infections in afebrile children with mildskeletal symptoms: the importance of blood cultures

Received: 18 March 2004 / Accepted: 27 May 2004 / Published online: 6 July 2004� Springer-Verlag 2004

Use of blood culture vials for culturing synovial fluidand bone exudates in recent years has resulted in therecognition of Kingella kingae, a commensal bacteriumof the respiratory tract, as an emerging pathogen inyoung children [2, 3, 5, 6]. The purpose of thisreport is to describe a novel presentation of invasiveK. kingae disease consisting of transient or mildskeletal symptoms, normal body temperature andbacteraemia

Young febrile patients referred to or admitted at theSoroka University Medical Centre in southern Israelundergo blood cultures using the BACTEC 9240 system.Because the region is endemic for brucellosis, bloodcultures are also routinely obtained from patientspresenting with bone or joint symptoms.

Between 1988 and 2003, K. kingae was isolatedfrom blood and/or other normally sterile body fluids in87 patients including 86 children and one adult.Involvement of the skeletal system was observed in 54patients of whom 42 had septic arthritis, 5 had osteo-myelitis, 1 patient had both, and 1 child each haddactylitis or tenosynovitis. In the remaining four chil-dren, an atypical syndrome consisting of bacteraemiaand transient or mild skeletal symptoms but noobjective signs of inflammation, such as effusion or

point tenderness, was noted (Table 1). A diagnosticblood culture was obtained in all four children, but noantibiotic therapy was initially administered. A fewdays later, patients returned to the hospital because ofisolation of K. kingae from the blood. On the follow-up visit, they were found to be afebrile and the acutephase reactants values had not changed significantly. Inpatients 1 and 2, the skeletal findings had not pro-gressed, and in patients 3 and 4 symptoms had totallyresolved. In all four cases a second blood culture wassterile and Doppler echocardiography ruled out bacte-rial endocarditis. A 99m Te diphosphonate bone scanwas performed in patients 1, 2, and 3 and was normal.Only patients 1 and 2 were given antibiotic therapy.All four children made a complete and uneventfulrecovery.

The patients herein described confirm that the clinicalpresentation of K. kingae infections is frequently benign[2, 3, 5, 6]. Because of lack of fever, good general con-dition and normal or slightly elevated acute phasereactants these patients could have been easily missed,and isolation of the organism from the blood was theonly evidence of the true nature of the disease [1, 3, 4].This unusual syndrome is probably the result of seedingof K. kingae to joints or bones during an episode ofbacteraemia followed by an effective immune responsethat eradicates the organism from the blood and theskeletal system. Although the symptoms of these chil-dren did not improve prior to the administration ofantibiotic therapy, their clinical condition did notworsen either. It should be pointed out, however, thatuntreated K. kingae bacteraemia may lead to seriouscomplications such as endocarditis or meningitis [1, 2, 3,4, 5, 6].

It is recommended that routine blood cultures usingspecial systems as BACTEC 9240 should be obtainedfrom young children presenting with skeletal complaintseven in the absence of fever, constitutional symptoms orleukocytosis.

P. Yagupsky (&)Clinical Microbiology Laboratory,Soroka University Medical Centrer,Ben-Gurion University of the Negev,84101 Beer-Sheva, IsraelE-mail: yagupsky@bgumail.bgu.ac.ilTel.: +972-86-400507Fax: +972-86-403541

J. PressPaediatric Emergency Department,Division of Paediatrics,Soroka University Medical Centrer,Ben-Gurion University of the Negev,Beer-Sheva, Israel

Eur J Pediatr (2004) 163: 563–564DOI 10.1007/s00431-004-1496-8

References

1. Birgisson H, Steingrimsson O, Gudnason T (1997) Kingellakingae infections in paediatric patients: 5 cases of septic arthritis,osteomyelitis and bacteraemia. Scand J Infect Dis 29: 495–498

2. Costers M, Wouters C, Moens P, Verhaegen J (2003) Three casesof Kingella kingae infection in young children. Eur J Pediatr 162:530–531

3. Dodman T, Robson J, Pincus D (2000) Kingella kingae infec-tions in children. J Paediatr Child Health 36: 87–90

4. Le CT (1983) Kingella ( Moraxella) kingae infections. Am J DisChild 137: 1212–1213

5. Moylett EH, Rossmann SN, Epps HR, Demmler GJ (2000)Importance of Kingella kingae as a pediatric pathogen in theUnited States. Pediatr Infect Dis J 19: 263–265

6. Yagupsky P, Bar-Ziv Y, Howard CB, Dagan R (1995) Epide-miology, etiology and clinical features of septic arthritis inchildren younger than 24 months. Arch Pediatr Adolesc Med149: 537–540

Table 1 Demographic, clinical and laboratory features of four patients with mild skeletal symptoms and K. kingae bacteraemia. (CTXceftriaxone)

Patient Age(months)

Sex Initial visit Follow-up visit

Temper-ature(�C)

Clinicalfeatures

WBC(/mm3)

ESR(mm)

Daya Temper-ature(�C)C

Clinicalfindings

WBC(/mm3)

ESR(mm)

Treatment Outcome

1 23 M 37.0 Limping for 1day; painfulmotion (hip)

9,700 25 5 37.0 Unchanged 10,300 35 CTX;

10 daysCured

2 27 M 37.8 Limping for 1day; painfulmotion (hip)

11,200 20 4 37.0 Unchanged 10,000 21 CTX;

10 daysCured

3 29 M 37.5 Limping for 1day; painfulmotion (knee)

13,300 38 4 37.5 Asymptomatic 12,700 Notdone

None Cured

4 18 M 36.0 Limping for 2days; nophysicalfindings

15,900 25 8 37.3 Asymptomatic 13,300 Notdone

None Cured

aDays after the initial visit to the Emergency Department

564