Isolation of two strains of Kingella kingae associated with septic arthritis

Kingella kingae: carriage, transmission, and disease

Kingella kingae is a common etiology of pediatric bacteremia and the leading agent of osteomyelitis and septic arthritis in children aged 6 to 36 months. This Gram-negative bacterium is carried asymptomatically in the oropharynx and disseminates by close interpersonal contact. The colonized epithelium is the source of bloodstream invasion and dissemination to distant sites, and certain clones show significant association with bacteremia, osteoarthritis, or endocarditis. Kingella kingae produces an RTX (repeat-in-toxin) toxin with broad-spectrum cytotoxicity that probably facilitates mucosal colonization and persistence of the organism in the bloodstream and deep body tissues. With the exception of patients with endocardial involvement, children with K. kingae diseases often show only mild symptoms and signs, necessitating clinical acumen. The isolation of K. kingae on routine solid media is suboptimal, and detection of the bacterium is significantly improved by inoculating exudates into blood culture bottles and the use of PCR-based assays. The organism is generally susceptible to antibiotics that are administered to young patients with joint and bone infections. β-Lactamase production is clonal, and the local prevalence of β-lactamase-producing strains is variable. If adequately and promptly treated, invasive K. kingae infections with no endocardial involvement usually run a benign clinical course.

Contribution of a broad range polymerase chain reaction to the diagnosis of osteoarticular infections caused by Kingella kingae: description of twenty-four recent pediatric diagnoses

BACKGROUND

Microbiologic diagnosis of septic arthritis and osteomyelitis in children is hindered by the less than optimal yield of blood and osteoarticular fluid cultures.

PATIENTS AND METHODS

All patients admitted to a pediatric unit for osteoarticular infections (OAI) between January 2001 and February 2004 were enrolled in this prospective study. Osteoarticular fluid and biopsy samples that were negative by conventional culture were tested by polymerase chain reaction (PCR) with universal 16S ribosomal DNA primers.

RESULTS

We enrolled 171 children. Culture was positive in 64 cases (37.4%), yielding Kingella kingae in 9 cases. The 107 culture-negative specimens were tested by 16S ribosomal DNA PCR. Fifteen samples (14%) were positive, all for Kingella DNA sequences. K. kingae was the second cause of OAI in this population (30.4%), after Staphylococcus aureus (38%). Patients with Kingella infection diagnosed by culture (9 cases) did not differ from those diagnosed by PCR (15 cases) in terms of their clinical characteristics (including prior antibiotic therapy). The characteristics of the 24 children with arthritis (n = 17) or osteomyelitis (n = 7) were similar to those reported elsewhere. Fever (>38 degrees C) and symptom onset shortly before hospitalization (median, 4.5 days) were significantly associated with arthritis.

CONCLUSION

Use of molecular diagnostic methods increases the identification of K. kingae in osteoarticular infections.

Kingella kingae: from medical rarity to an emerging paediatric pathogen

In recent years, Kingella kingae has emerged as an important cause of invasive infections in young children, especially septic arthritis, osteomyelitis, spondylodiscitis, bacteraemia, and endocarditis, and less frequently lower respiratory tract infections and meningitis. The organism is part of the pharyngeal flora of young children and is transmitted from child-to-child. The clinical presentation of invasive K kingae disease is often subtle and laboratory tests are frequently normal. A substantial fraction of children with invasive K kingae infections have a recent history of stomatitis or symptoms of upper-respiratory-tract infection. The organism is susceptible to a wide array of antibiotics that are usually given empirically to young children including beta lactams, and with the exception of cases of endocarditis, the disease runs a benign clinical course. Although isolation and recognition of the organism is not difficult, clinicians and microbiologists should be aware of its fastidious nature. To optimise the recovery of K kingae, inoculation of synovial fluid specimens into blood culture vials is strongly recommended.

Kingella kingae infections in children

OBJECTIVE

To increase awareness of Kingella kingae infections in children by presenting four cases seen at the Gold Coast Hospital, Southport, Queensland, and reviewing the literature.

METHODOLOGY

Records of the four cases were reviewed and relevant information described. A MEDLINE search of the English literature from 1983 to 1998 was conducted.

RESULTS

Osteoarticular infections are the commonest type of invasive paediatric infection but bacteraemia and endocarditis also occur. Isolation of the organism is difficult but inoculation of the specimen into enriched blood culture systems improves the recovery rate. The majority of isolates are sensitive to beta-lactam antibiotics but resistance has been described.

CONCLUSIONS

Kingella kingae infections in children are more common than previously recognized. The organism should be actively sought in any child with suspected osteoarticular infections. Recommended empiric therapy is a third generation cephalosporin until susceptibility to penicillin is confirmed.

Kingella kingae infections in paediatric patients: 5 cases of septic arthritis, osteomyelitis and bacteraemia

Kingella kingae is a Gram-negative rod most often recognized as 1 of the organisms causing septic arthritis and osteomyelitis in children. Infection caused by K. kingae had not been diagnosed in Iceland until 5 cases were diagnosed at the Paediatric Department at the University Hospital of Iceland over a 1 year period. In this report we describe these 5 children with invasive infection caused by K. kingae (2 with septic arthritis, 1 with osteomyelitis, 1 with septic arthritis and osteomyelitis, and 1 with bacteraemia) and review the literature. All bacterial isolates were identified by the Bactec culture system.

Endocarditis caused by Kingella denitrificans

We report the case of a 48-year-old man with native valve endocarditis caused by Kingella denitrificans. He was successfully treated with a combination of beta-lactam antibiotics and aminoglycosides, after which he underwent valve replacement surgery. This case represents the first report in the literature of elective native valve replacement. Previously reported cases are discussed together with management options, including suggestions for the treatment of patients with beta-lactam allergy and those infected with beta-lactamase producing strains.

Isolation of Kingella kingae from a corneal ulcer

Kingella kingae was isolated from a corneal ulcer in an 11-month-old male. This organism has been previously reported from normally sterile sites, including sites of endophthalmitis, but this is the first time isolation from the cornea has been reported.

High prevalence of Kingella kingae in joint fluid from children with septic arthritis revealed by the BACTEC blood culture system

In an effort to improve detection of fastidious organisms, joint fluid aspirates of pediatric patients were inoculated into BACTEC 460 aerobic blood culture bottles, in addition to cultures on solid media. Culture records for the 1988 to 1991 period were reviewed to compare the performance of both methods for the recovery of pathogens. Overall, 216 children underwent a diagnostic joint tap, and 63 specimens grew significant organisms, including Kingella kingae in 14. While both methods were comparable for recovery of usual pathogens, with a single exception, K. kingae isolates were detected by the BACTEC system only. K. kingae appears to be a more common cause of septic arthritis in children than has been previously recognized. The BACTEC blood culture system enhances the recovery of K. kingae from joint fluid and improves bacteriologic diagnosis of pediatric septic arthritis.

Osteoarticular infections due to Kingella kingae in children

By the description of two cases of osteoarticular infections due to Kingella kingae in two young children we wish to draw the attention of clinicians to invasive infections due to this micro-organism. Since its biological characterization in 1976, K. kingae has been increasingly reported as a human pathogen. Most common presentations are endocarditis, bacteraemia, septic arthritis, osteomyelitis and spondylodiscitis. Interestingly, osteorticular involvement is largely predominant in previously healthy children. From the literature, we reviewed 51 cases of K. kingae bone and joint infections, representing 23 cases of septic arthritis, 17 of osteomyelitis and 11 spondylodiscitis. Of the cases 88% occurred in children below 5 years of age and in all cases only one bone or joint was involved. An underlying disorder could be found in only 4 patients. Since these infections have a favourable outcome with intravenous antibiotic treatment, proper isolation and identification of K. kingae is essential.

Kingella kingae intervertebral disk infection

Disk inflammation in children is believed to result from infection, and Staphylococcus aureus is reported to be the organism most commonly isolated from cases of intervertebral disk infection. A case of disk inflammation caused by the unusual pathogen Kingella kingae is described. The antibiotic susceptibility of other K. kingae isolates and the clinical features of 11 other previously reported cases of disk infection caused by this microorganism are reviewed.

Spondylitis and osteomyelitis caused by Kingella kingae in children

Two cases of documented osteoarticular infections caused by Kingella kingae in children are reported. The main bacteriological characteristics and antibiotic susceptibilities of these two isolates are described. The pathology of K. kingae, particularly in bones and joints, is reviewed.