Osteoarticular infection in children.

AIMS: We aimed to describe the epidemiological, biological, and bacteriological characteristics of osteoarticular infections (OAIs) caused by Kingella kingae. METHODS: The medical charts of all children presenting with OAIs to our institution over a 13-year period (January 2007 to December 2019) were reviewed. Among these patients, we extracted those which presented an OAI caused by K. kingae and their epidemiological data, biological results, and bacteriological aetiologies were assessed. RESULTS: K. kingae was the main reported microorganism in our paediatric population, being responsible for 48.7% of OAIs confirmed bacteriologically. K. kingae affects primarily children aged between six months and 48 months. The highest prevalence of OAI caused by K. kingae was between seven months and 24 months old. After the patients were 27 months old, its incidence decreased significantly. The incidence though of infection throughout the year showed no significant differences. Three-quarters of patients with an OAI caused by K. kingae were afebrile at hospital admission, 11% had elevated WBCs, and 61.2% had abnormal CRPs, whereas the ESR was increased in 75%, constituting the most significant predictor of an OAI. On MRI, we noted 53% of arthritis affecting mostly the knee and 31% of osteomyelitis located primarily in the foot. CONCLUSION: K. kingae should be recognized currently as the primary pathogen causing OAI in children younger than 48 months old. Diagnosis of an OAI caused by K. kingae is not always obvious, since this infection may occur with a mild-to-moderate clinical and biological inflammatory response. Extensive use of nucleic acid amplification assays improved the detection of fastidious pathogens and has increased the observed incidence of OAI, especially in children aged between six months and 48 months. We propose the incorporation of polymerase chain reaction assays into modern diagnostic algorithms for OAIs to better identify the bacteriological aetiology of OAIs. Cite this article: Bone Joint J 2021;103-B(3):578-583.

Kingella kingae and Osteoarticular Infections.

OBJECTIVES: In this study, we aimed to contrast the bacteriologic epidemiology of osteoarticular infections (OAIs) between 2 patient groups in successive 10-year periods, before and after the extensive use of nucleic acid amplification assays in the diagnostic process. METHODS: Epidemiologic data and bacteriologic etiologies of all children presenting with OAIs on admission to our institution over 20 years (1997-2016) were assessed retrospectively. The population was divided into 2 cohorts, using the standardized use of polymerase chain reaction as the cutoff point (2007). The conventional cohort included children with OAIs mainly investigated by using classic cultures, whereas the molecular cohort referred to patients also investigated by using molecular assays. RESULTS: Kingella kingae was the most frequently isolated pathogen, responsible for 51% of OAIs, whereas other classic pathogens were responsible for 39.7% of cases in the molecular cohort. A statistically significant increase in the mean incidence of OAIs was observed, as was a decrease in the mean age at diagnosis after 2007. After 2007, the pathogen remained unidentified in 21.6% of OAIs in our pediatric population. CONCLUSIONS: Extensive use of nucleic acid amplification assays improved the detection of fastidious pathogens and has increased the observed incidence of OAI, especially in children aged between 6 and 48 months. We propose the incorporation of polymerase chain reaction assays into modern diagnostic algorithms for OAIs to better identify the bacteriologic etiology of OAIs.

The Contemporary Bacteriologic Epidemiology of Osteoarticular Infections in Children in Switzerland.

OBJECTIVES: To assess the contemporary bacteriologic epidemiology of pediatric osteoarticular infection with particular regard to children's ages, because Kingella kingae has gained increasing recognition as the predominant pathogen for osteoarticular infection in young children. STUDY DESIGN: Retrospective file review of enrolled children from 0 to 15 years of age, admitted to our institution from 2007 to 2015 for suspected osteoarticular infection (217 cases). Information on age, sex, the bone or joint infected, imaging studies, and laboratory data (including bacterial investigations) were collected for analysis. RESULTS: Microorganism identification was possible for 138 infected children (63.6%), through blood (cultures or polymerase chain reaction [PCR]) and/or operative samples (cultures or PCR). Thirty-one patients (14.3%) were found to both have positive blood cultures and operative samples. The results of positive bacteriology specimens identified the most common causative pathogen for osteoarticular infection as K kingae (47.8% of microbiologically confirmed osteoarticular infections of all ages, and 87.7% in children between the ages of 6 and 48 months), significantly more common than Staphylococcus aureus (35.5% of microbiologically confirmed osteoarticular infections of all ages, and 78.2% in children >4 years of age). CONCLUSIONS: Use of the appropriate PCR assays demonstrated that K kingae currently is the major bacterial cause of pediatric osteoarticular infection, especially in children <4 years of age in whom K kingae is more common than S aureus. PCR assays should be used in routine microbiologic laboratory evaluation to improve diagnostic performance. However, despite the use of molecular methods, there are many osteoarticular infections in which no microorganism is detected, which suggests that these infections may be caused by other as yet unrecognized fastidious microorganisms.

Pyogenic Tenosynovitis in Infants: A Case Series.

Pyogenic tenosynovitis is an uncommon condition in children, and there are few published case reports. We present a series of 11 cases who were treated in the Geneva Children Hospital in the last 10 years. Kingella kingae was the main pathogen, and the characteristics of infection (inflammatory indices, clinical findings and severity) are similar to other osteoarticular K. kingae infections in infants.

Pediatric Sacroiliitis: Clinical and Microbiologic Differences Between Infants and Children-Adolescents.

BACKGROUND: The aim of this study was to improve knowledge of pediatric pyogenic sacroiliitis (PSI) in the pediatric population based on a consecutive case series. METHOD: We conducted a single-center cross-sectional study on 16 patients admitted to the emergency department of our Hospital between January 1990 and December 2015 with a confirmed diagnosis of PSI. The patients were divided into 2 groups by age: infants (6 months to 4 years) and children-adolescents (4-16 years). The features of PSI, clinical signs and symptoms, laboratory tests, bacteriologic investigations, radiologic examinations and outcome were compared among the 2 groups. RESULTS: Patients in the children-adolescent group usually presented with a history of limping and buttock or lower back pain, and methicillin-susceptible Staphylococcus aureus was the most frequent pathogen. We observed a second peak of incidence of PSI in infants with consistent difference in clinical and microbiologic presentation. Infants were more likely to have an ambiguous onset with the refusal to bear weight as the only consistent clinical manifestations, and biologic investigations demonstrated higher erythrocyte sedimentation rate and platelet counts. However, all blood and joint fluid cultures were sterile in the infant group. CONCLUSION: PSI in infants and adolescents may represent 2 different conditions. Although PSI is mainly caused by S. aureus in the children-adolescent group, clinical manifestations and biologic characteristics of PSI in infants suggest Kingella kingae as the etiology osteoarticular infection. Thus, oropharyngeal swab polymerase chain reaction assay for K. kingae and magnetic resonance imaging should be considered for early diagnosis and treatment of this condition in the younger age group.