Specific real-time polymerase chain reaction places Kingella kingae as the most common cause of osteoarticular infections in young children

BACKGROUND: The use of universal 16S rDNA polymerase chain reaction (PCR) has recently shown that the place of Kingella kingae in osteoarticular infections (OAI) in young children has been underestimated, but this technique is not the most sensitive or the most rapid method for molecular diagnosis. We developed a specific real-time PCR method to detect K. kingae DNA and applied it to the etiologic diagnosis of OAI. PATIENTS AND METHODS: All children admitted to a pediatric unit for OAI between January 2004 and December 2005 were enrolled in this prospective study. Culture-negative osteoarticular specimens were tested by 16S rDNA PCR and by K. kingae-specific real-time PCR when sufficient sample remained. RESULTS: By culture alone, a pathogen was identified in 45% of the 131 specimens tested (Staphylococcus aureus, n = 25; K. kingae, n = 17; others, n = 18). 16S rDNA PCR and K. kingae-specific PCR were both applied to 61 of the culture-negative samples. The combination of culture and 16S rDNA PCR identified a pathogen in 61% of cases (K. kingae DNA, n = 16; DNA of other microorganisms, n = 5). Specific real-time PCR identified a further 6 cases caused by K. kingae and confirmed all 16 universal PCR-positive cases, bringing the overall documentation rate to 66%. K. kingae was the leading cause of OAI in this pediatric series (n = 39, 45%), followed by S. aureus (n = 25, 29%) CONCLUSION: The K. kingae-specific real-time PCR places K. kingae as the leading cause of OAI in children at our hospital.     

Kingella kingae osteoarticular infections in children. A report of a series of eight new cases]

Kingella kingae is a Gram-negative bacillus which belongs to the Neisseriaceae family. Its involvement in osteoarticular infections is relatively recent. METHODS AND RESULTS: We report eight cases of Kingella kingae osteoarticular infections that have been diagnosed at the paediatric surgical centre of Rouen University Hospital since October 1995. Six boys and two girls (mean age: 30.6 months) presented with osteomyelitis in six cases and arthritis in two. Only 75% of patients had a fever at time of diagnosis. The biological findings were slightly modified. All samples were obtained from blood, bone or joint fluid. These samples were systematically inoculated into a blood culture tube. Positive Kingella kingae culture was achieved in seven local samples and in one blood culture. All children received two antibiotics via intravenous injection while waiting for the bacteriologic results. Later, the antibiotic treatment (amoxycillin) was given per os. The mean duration of treatment was 33 days. Patients were given intravenous treatment for a period of only ten days. Six patients were followed up for a period of more than 18 months and outcome was always uneventful. DISCUSSION: Kingella kingae is usually present in the nasopharyngeal mucosa and spreads in the blood due to various infections. Different types of Kingella kingae infection have been reported with a large frequency of osteoarticular infection. CONCLUSION: This type of infection does not present any unusual characteristics as compared to other osteoarticular infections. Because of its antibiotic sensitivity treatment duration could be reduced. Kingella kingae is a fragile microbe and its culture is often difficult; therefore, it is important to use blood culture tubes to inoculate joint fluid and bone samples.     

Acute osteomyelitis and septic arthritis in children: one year experience]

To describe bacteriologic epidemiology of bone and joint infections, a total of 52 osteomyelitis, 52 arthritis and 20 osteoarthritis of children aged one month to 15 years during a one-year period (2001) were included in a retrospective unicentric review. The mean age was 3,9 +/-3,6 years. Fever and pain were the most common clinical symptoms. The site of infection was single in 95%, involving lower extremities in 80%. Bone scintigraphy was abnormal in 71% of osteomyelitis. Positive cultures was obtained in 29% of all cases (blood cultures: 20%, aspiration cultures: 29%), but in 42% of cases which have both blood and aspiration cultures. Thirty-six bacteria were identified: 19 Staphylococcus (14 aureus), ten Streptococcus (four pneumoniae), three Salmonella, three Kingella kingae, one Moraxella. All the isolates were susceptible to the empiric antibiotic therapy. Outcome was good in 100% of osteomyelitis and in 96% of arthritis.     

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: a rare cause of meningitis]

Kingella kingae is the second most frequent germ involved in arthritis affecting young children. This germ isolation on ordinary environment is difficult, which may explain why it is seldom known. It is now widely accepted that a direct inoculate of articular and osseous samples on liquid substrate improves the culture sensitivity. Other septic localizations have been described such as endocarditis or, less commonly, meningitis. CASE REPORT: We report the observation of a five-year-old child, treated for meningitis, with CSF culture showing evidence of scarce colonies of Kingella kingae. CONCLUSION: By analogy with arthritis, Kingella kingae may regularly be undetected, not being isolated, in some cases of non-documented meningitis with a cerebrospinal fluid (CSF) cytology recalling a bacterial origin. It would be of interest to verify if the seeding of CSF in liquid substrate would increase the sensitiveness of the cultures.     

Differentiating osteoarticular infections caused by Kingella kingae from those due to typical pathogens in young children

Osteoarticular infections caused by Kingella kingae are characterized by mild-to-moderate clinical and biologic inflammatory signs that are different from those caused by Gram-positive cocci. A combined score was built to find the best model to predict K. kingae osteoarticular infections by using the following 4 variables: body temperature <38°C, serum C-reactive protein <55 mg/L, white blood cell count <14,000/mm, and band forms <150/mm.     

Kingella kingae: an emerging pathogen in young children

Kingella kingae is being recognized increasingly as a common etiology of pediatric osteoarticular infections, bacteremia, and endocarditis, which reflects improved culture methods and use of nucleic acid-amplification techniques in clinical microbiology laboratories. K kingae colonizes the posterior pharynx of young children and is transmitted from child to child through close personal contact. Day care attendance increases the risk for colonization and transmission, and clusters of K kingae infections among day care center attendees have been reported. Key virulence factors in K kingae include type IV pili and a potent RTX toxin. In previously healthy children, >95% of K kingae infections are diagnosed between the ages of 6 and 48 months. Among children with underlying medical conditions, K kingae disease may occur at older ages as well. The clinical presentation of K kingae disease is often subtle and may be associated with normal levels of acute-phase reactants, which underscores the importance of a high index of suspicion. K kingae is usually susceptible to ?-lactam antibiotics, and infections typically respond well to medical treatment, with the exception of cases of endocarditis.     

Outbreak of Kingella kingae skeletal system infections in children in daycare

OBJECTIVE: The objective of this study is to describe the investigation of an outbreak of one culture-proven and two presumptive cases of Kingella kingae osteomyelitis detected within a 15-day period in a daycare center in Israel. METHODS: Surveillance pharyngeal cultures were obtained from all attendees at the index daycare center and from two neighboring facilities. Combined amoxicillin-rifampin prophylaxis was administered to all children aged 6 to 30 months living in the community. K. kingae isolates were typed by pulsed field gel electrophoresis, random amplified polymorphic DNA analysis and sequencing of the rRNA genes. RESULTS: Surveillance cultures showed that four of 11 attendees at the index facility as well as five of 12 and one of 15 attendees at neighboring daycare centers carried K. kingae. Typing of isolates showed that the isolate from a child with osteomyelitis was identical to all other isolates from the same daycare center and different from organisms derived from the other facilities. Administration of prophylactic antibiotics resulted in partial eradication of the organism. CONCLUSIONS: Dissemination of K. kingae in a susceptible pediatric population may result in an outbreak of invasive disease. Our experience suggests the need for increased alertness for clusters of K. kingae infections among children in daycare.     

Multifocal invasive Kingella kingae infection]

CASE REPORT: A 2-year-old child, non immunodeficient, presented with septicemia due to Kingella kingae successively complicated by meningitis, arthritis of one knee and endocarditis. Outcome was favourable after a long and adjusted antibiotherapy, involving in particular for the endocarditis ceftriaxone (100 mg/kg/d) and amikacin (20 mg/kg/d) during 3 weeks, then amoxicillin per os (200 mg/kg/d) during 3 weeks. CONCLUSIONS: Bacteriologic characteristics of the bacteria, the culture of which requires medium base with additional nutrient are reviewed. The tropism of Kingella kingae is essentially osteoarticular and cardiac as shown by the cases reported in the literature. Its susceptibility to antibiotics explains the frequent favourable outcome.     

Septic arthritis caused by Kingella kingae

Kingella kingae is a slow-growing, fastidious gram-negative coccobacillus that is a normal inhabitant of the oropharynx of man, but it has rarely been implicated as a human pathogen. Two cases of septic arthritis caused by this organism are reported along with a review of seven previously reported cases of infections caused by this organism. Bone and joint infections predominate. Gram's-stained smears of pus from bone or joint fluid aspirate have been negative for organisms, and a delay of growth in cultures with initial difficulty in classification of the isolate is characteristic. Kingella kingae organisms have been uniformly sensitive to the penicillins and all other commonly used antibiotics that were tested. Response to treatment was good in all nine patients found to have infections caused by this organism.     

Small risk of osteoarticular infections in children with asymptomatic oropharyngeal carriage of kingella kingae

The aim of this study was to evaluate the absolute risk for children younger than 4 years of age with asymptomatic oropharyngeal carriage of Kingella kingae to sustain an osteoarticular infection. The rate of K. kingae carriage in the oropharyngeal mucosa was 9% among healthy children, and the risk for an asymptomatic carrier to develop an osteoarticular infection due to K. Kingae was estimated to be lower than 1%.     

Bacterial aetiology of acute osteoarticular infections in children

Aim: To study the bacterial aetiology of acute osteoarticular infections in children and to analyse the efficiency of culture methods. Methods: Bacteriological data of 407 cases of clinically suspected osteoarticular infections affecting 406 children hospitalized in an orthopaedic surgery department between 1999 and 2002 were retrospectively reviewed. Results: Bacterial cultures from clinical specimens were positive in 74 cases (18%): 38 cases of septic arthritis and 36 cases of bone infections (osteitis, osteomyelitis or osteoarthritis). The use of liquid medium bottles to grow bacteria from articular fluids increased the rate of positive cultures compared to the use of standard solid media (p=0.0001). The most commonly recovered pathogen was Staphylococcus aureus (44%) followed by Kingella kingae (14%), Streptococcus pyogenes (10%) and Streptococcus pneumoniae (10%). K. kingae was most frequently isolated among children under 36 mo of age (p=0.0003), whereas S. aureus was most frequently isolated among children over 36 mo (p=0.0015).

Conclusion: By improving our culture method, we observed a recrudescence of isolation of K. kingae, but S. aureus remains the main pathogen isolated from osteoarticular infections in children. This finding is useful for the adaptation of a probabilistic antibiotic treatment of these infections.     

Enhanced culture detection of Kingella kingae, a pathogen of increasing clinical importance in pediatrics

Osteoarticular infection and occult bacteremia are the 2 invasive infectious pathologies most frequently associated in childhood with Kingella kingae. We report a series of 11 patients in whom osteomyelitis predominates over septic arthritis, which is the reverse of other series, probably as a consequence of inoculation of samples during surgery on agar media, used in combination with or as an alternative to inoculation into blood culture bottles. Although K. kingae infections usually follow a benign clinical course, we noted 2 patients with mild orthopedic sequelae.     

Comparison of clinical and biologic features of Kingella kingae and Staphylococcus aureus arthritis at initial evaluation

We conducted a retrospective study comparing the presenting clinical and biologic features of 64 children who had septic arthritis caused by Kingella kingae with 26 children who had septic arthritis caused by Staphylococcus aureus. Children with K. kingae septic arthritis were significantly younger than those with S. aureus septic arthritis. Otherwise, there were no significant differences between the 2 groups with respect to fever, location, white blood cell count, synovial fluid cell count, C-reactive protein, or serum fibrinogen. However, the clinical course was significantly better for children with septic arthritis caused by K. kingae as evidenced by shorter hospitalization and fewer adverse events. Presumptive antibiotic therapy for septic arthritis in young infants should take into account both of these pathogens, even in case of mild presentation.     

Joint and bone infections due to anaerobic bacteria in children

The current review describes the microbiology, diagnosis and management of septic arthritis and osteomyelitis due to anaerobic bacteria in children. Staphylococcus aureus, Haemophilus influenzae type-b, and Group A streptococcus, Streptococcus pneumoniae, Kingela kingae, Neisseria meningiditis and Salmonella spp are the predominant aerobic bacteria that cause arthritis in children. Gonococcal arthritis can occur in sexually active adolescents. The predominant aerobes causing osteomyelitis in children are S. aureus, H. influenzae type-b, Gram-negative enteric bacteria, beta-hemolytic streptococci, S. pneumoniae, K. kingae, Bartonella henselae and Borrelia burgdorferi. Anaerobes have rarely been reported as a cause of these infections in children. The main anaerobes in arthritis include anaerobic Gram negative bacilli including Bacteroides fragilis group, Fusobacterium spp., Clostridium spp. and Peptostreptococcus spp. Most of the cases of anaerobic arthritis, in contrast to anaerobic osteomyelitis, involved a single isolate. Most of the cases of anaerobic arthritis are secondary to hematogenous spread. Many patients with osteomyelitis due to anaerobic bacteria have evidence of anaerobic infection elsewhere in the body, which is the source of the organisms involved in osteomyelitis. Treatment of arthritis and osteomyelitis involving anaerobic bacteria includes symptomatic therapy, immobilization in some cases, adequate drainage of purulent material and antibiotic therapy effective to these organisms.     

Empiric antibiotic therapy for acute osteoarticular infections with suspected methicillin-resistant Staphylococcus aureus or Kingella

The bacterial agents causing bone and joint infections have been changing. Currently, methicillin-resistant Staphylococcus aureus (MRSA) and Kingella kingae are emerging pathogens. For treatment of MRSA infections, clindamycin, vancomycin, and linezolid are commonly prescribed antibiotics. Kingella are sensitive to most penicillins and cephalosporins. Because MRSA osteoarticular infections tend to be severe, longer periods of antibiotic treatment with more frequent monitoring of inflammatory markers are sometimes required to obtain a complete cure with no residual complications. To assist management, we have included a clinical decision tree with antibiotic treatment protocols.     

Etiology of septic arthritis in children: an update for the 1990s

OBJECTIVE: To establish the etiology of septic arthritis in children after implementation of HIB immunization guidelines. METHODS: A retrospective review of all charts with a discharge diagnosis of septic arthritis (ICD-9: 711) from January 1991 to December 1996 at St. Louis Children's Hospital was conducted. RESULTS: Sixty-four patients (male = 58%) were identified, whose median age was 6.0 years. Twenty-one children (33%) were misdiagnosed on initial presentation. An organism was isolated in 38 (59%) of cases. The predominant organisms were Staphylococcus aureus (10 isolates), Group A Streptococcus (4), Enterobacter species (4), Kingella kingae (3), Neisseria meningitides (3), Streptococcus pneumoniae (2), Neisseria gonorrhoeae (2), Candida (2), Staphylococcus epidermidis (2). The only isolate of Haemophilus influenzae type B was in 1992 in an unimmunized 14 month old. CONCLUSIONS: These data confirm Staphylococcus aureus as a frequent pathogen and suggest that H influenzae type B is no longer the predominant isolate in young children with septic arthritis. In addition, early septic arthritis in children is frequently misdiagnosed on initial evaluation.     

Acute osteomyelitis and septic arthritis in children

OBJECTIVE: To review the clinical presentation, clinical management and organisms responsible for acute haematogenous osteomyelitis (AHO) and septic arthritis (SA) in the post Haemophilus influenzae type B (Hib) vaccine era and to evaluate current Australian antibiotic guidelines for these conditions. METHODS: A retrospective chart review of children less than 16 years of age presenting to The Children's Hospital at Westmead in the period from January 1998 to July 2002 with an ICD discharge code consistent with AHO or SA. RESULTS: During the 4 1/2-year period 120,511 children were admitted to The Children's Hospital at Westmead. There were 102 cases of AHO and 47 cases of SA during this time. An organism was identified either by blood culture or tissue biopsy in 45% of children with AHO and 38% with SA. Staphylococcus aureus was the most common identifiable causative organism accounting for 76% of isolated organisms in AHO and 39% of isolated organisms in SA. Methicillin-resistant S. aureus (MRSA) was responsible for 9% of AHO and 6% of SA cases. There were no cases due to Haemophilus influenzae or Kingella kingae during the study period. The majority (66%) of children with AHO were managed non-operatively with intravenous and then oral antibiotics. Thirty-five (34%) children had operative treatment to drain pus. In contrast, 74% of the patients with SA had one or more surgical procedures performed to drain pus from involved joints. CONCLUSIONS: Staphylococcus aureus remains the most common organism causing AO and SA; however, community-acquired methicillin-resistant strains are now occurring. Haemophilus influenzae is no longer a common cause of SA. Our study supports the current Australian antibiotic guidelines that recommend flucloxacillin alone as the empiric treatment of choice of both AHO and SA in children fully immunised against Hib. However the possibility of community-acquired MRSA should be considered, particularly in high risk groups such as indigenous Australian children or children from regional areas with a high rate of community-acquired MRSA.     

Kingella kingae osteomyelitis

A case of Kingella kingae osteomyelitis characterized by an early onset of cellulitis, positive blood culture and negative bone scintigraphy is reported. Exclusive of vertebral involvement, eleven cases have been described in the pediatric literature. The bacterial nature of this disorder may prove hard to demonstrate since fever, leucocytosis, and increased CRP levels are inconstant. The difficulties of isolation and growth of Kingella kingae as well as its likely resistance to antistaphylococcal agents constitute the main features of this type of infection.