Search Results (23)

Background/Objectives: This study aims to evaluate the impact of the PCR multiplex panel (BioFire JI^®) on the diagnosis and management of pediatric osteoarticular infections. Methods: This retrospective study analyzed data from pediatric patients diagnosed with osteoarticular infections between January 2023 and April 2024. The effectiveness of the PCR multiplex panel in identifying pathogens was compared with traditional culture methods. Results: In total, 50 patients were identified (66.6% male, 74% under 3 years of age). They were diagnosed as follows: septic arthritis in 46%, osteomyelitis in 26%, and septic osteoarthritis in 22%. An identifiable agent was isolated by conventional culture in 22 cases (44%). Kingella kingae was the predominant pathogen identified, accounting for 50% of cases (11/22), followed by Staphylococcus aureus (9/22). The BioFire JI^® Panel PCR demonstrated a sensitivity of 93%, with a specificity of 63% when evaluated against synovial fluid culture as the reference standard. The panel identified seven additional pathogens not detected by conventional culture methods: 2/9 MSSA (22%), 1/1 S. pyogenes (100%), and 4/11 K. kingae (37%), increasing the yield by 14%. The rapid identification of pathogens facilitated timely and targeted therapeutic interventions. Conclusions: The PCR multiplex panel (BioFire JI^®) improved the diagnosis of pediatric osteoarticular infections. Full article

Pediatric septic arthritis of the hip (SAH) in children is a severe pathology, requiring prompt diagnosis and treatment to avoid destructive sequelae of the joint. Its diagnosis can be challenging, however, due to its spectrum of manifestations and differential diagnosis. Last century, multiple research teams studied the curves of systemic inflammation markers to aid the differential diagnosis. Kocher showed that a history of fever >38.5 °C, non-weight bearing, an erythrocyte sedimentation rate >40 mm/h, and serum white blood cells >12,000/mm³ were highly suggestive of SAH, with a predicted probability of 99.6% when all these predictors manifested in pediatric patients. Caird validated these criteria, also adding a C-reactive protein >20 mg/L, reaching a 98% probability of SAH when these five criteria were present. The Kocher and the Caird criteria were then applied in multiple settings, but were never clearly validated. Moreover, they were studied and validated in the years when Kingella kingae was just emerging, and this was probably responsible for false-negative cases in multiple centers. For this reason, the Kocher and the Caird criteria are still at the center of a debate on the diagnostic tools for pediatric SAH. We provide a historical overview of the development of clinical and laboratory test algorithms for pediatric SAH. Further, new perspectives for future research on the prediction rules of pediatric SAH are here proposed. Full article

Objectives: Septic arthritis (SA) is a serious bacterial infection that must be treated efficiently and timely. The large number of culture-negative cases makes local epidemiological data important. Accordingly, this study aimed to evaluate the etiology, clinical characteristics, and therapeutic approach of SA in children in Turkiye, emphasizing the role of real-time polymerase chain reaction (PCR) techniques in the diagnosis. Methods: In this multi-center, prospective study, children hospitalized due to SA between February 2018 and July 2020 in 23 hospitals in 14 cities in Turkiye were included. Clinical, demographic, laboratory, and radiological findings were assessed, and real-time PCR was performed using synovial fluid samples. Results: Seventy-five children aged between 3 and 204 months diagnosed with acute SA were enrolled. Joint pain was the main complaint at admission, and the most commonly involved joints were the knees in 58 patients (77.4%). The combination of synovial fluid culture and real-time PCR detected causative bacteria in 33 patients (44%). In 14 (18.7%) patients, the etiological agent was demonstrated using only PCR. The most commonly isolated etiologic agent was Staphylococcus aureus, which was detected in 22 (29.3%) patients, while Streptococcus pyogenes was found in 4 (5.3%) patients and Kingella kingae in 3 (4%) patients. Streptococcus pyogenes and Kingella kingae were detected using only PCR. Most patients (81.3%) received combination therapy with multiple agents, and the most commonly used combination was glycopeptides plus third-generation cephalosporin. Conclusions: Staphylococcus aureus is the main pathogen in pediatric SA, and with the use of advanced diagnostic approaches, such as real-time PCR, the chance of diagnosis increases, especially in cases due to Kingella kingae and Streptococcus pyogenes. Full article

Infective endocarditis due to Kingella kingae is a rare but serious invasive infection that occurs mostly in children. Recent advances in nucleic acid amplification testing as well as in cardiac imaging have enabled more accurate diagnosis. A good understanding of the epidemiology and virulence factors remains crucial to guide the therapeutic approach. Here, we synthesize the current state of knowledge on epidemiological features, pathophysiological insights, complications, and therapy regarding Kingella kingae endocarditis in children and adults. Finally, throughout this comprehensive review, knowledge gaps and areas for future research are also identified. Full article

Pediatric osteoarticular infections (OAIs) are serious conditions that can lead to severe septic complications, prolonged morbidity with long-term impaired function, and perturbed subsequent bone development. Kingella kingae (K. kingae) is currently accepted as the predominant pathogen in pediatric OAIs, especially among 6–48 month olds. The present study aimed to identify clinical and biological markers that would refine the detection of patients with an OAI due to K. kingae. We retrospectively studied every consecutive case of pediatric OAI admitted to our institution over 17 years. Medical records were examined for patient characteristics such as temperature at admission, affected segment, and biological parameters such as white blood cell (WBC) count, left shift, platelet count (PLT), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). The 247 patients included 52.2% males and 47.8% females and mean age was 18.5 ± 10 months old. Four patients were older than 48 months; none were younger than 6 months old. Mean temperature at admission was 37.4 ± 0.9 °C. Regarding biological parameters, mean WBC count was 12,700 ± 4180/mm³, left shift was only present in one patient, mean PLT was 419,000 ± 123,000/mm³, mean CRP was 26.6 ± 27.8 mg/L, and mean ESR was 35.0 ± 18.9 mm/h. Compared to the modified predictors of OAI defined by Kocher and Caird, 17.2% of our cases were above their cut-off values for temperature, 52.3% were above the WBC cut-off, 33.5% were above the ESR cut-off, and 46.4% were above the CRP cut-off. OAIs due to K. kingae frequently remain undetected using the classic biological parameters for investigating bacterial infections. As an addition to the predictors normally used (°C, WBC, CRP, and ESR), this study found that elevated platelet count was frequently present during OAIs caused by K. kingae. Although this biological characteristic was inconstant, its presence was highly significant and very suggestive of an invasive infection due to K. kingae. Full article

Our understanding of pediatric osteoarticular infections (OAIs) has improved significantly in recent decades. Kingella kingae is now recognized as the most common pathogen responsible for OAIs in pediatric populations younger than 4 years old. Research has provided a better understanding of the specific types, clinical characteristics, biological repercussions, and functional outcomes of these infections. Hands and wrists are rarely infected, with few reports available in the literature. The present study aimed to examine this specific condition in a large patient cohort, explore the implications for each anatomical area using magnetic resonance imaging (MRI), and critically evaluate the evolution of therapeutic management. Full article

Transphyseal hematogenous osteomyelitis (THO) is a serious condition that can affect the growing physis, yet it is insufficiently recognized in children. The aim of this study was to explore the prevalence and epidemiology of pediatric THO, and to discuss the underlying pathophysiology. All consecutive cases of acute and subacute osteomyelitis admitted to our institution over 17 years were retrospectively studied. Medical records were examined for patient characteristics, bacteriological etiology, and medical and surgical management. Magnetic resonance imaging was reviewed for all patients to identify those with transphyseal spread of infection. For positive cases, the surface area of the transphyseal lesion was estimated relative to the total physeal cross-sectional area. Fifty-four (25.7%) of the 210 patients admitted for acute or subacute osteomyelitis were diagnosed with THO. The study population’s ages ranged from 1 month to 14 years old (median age 5.8 years, interquartile range 1–167 months). Fourteen (25.9%) patients were younger than 18 months old; the remaining 40 (74.1%) had a mean age of 8.5 years old. The most common sites of THO were the distal tibia (29.1%), the proximal tibia (16.4%), and the distal fibula (14.5%). Transphyseal lesions were due to acute infection in 41 cases and to subacute osteomyelitis in 14 cases. The two most frequently identified pathogens were Staphylococcus aureus (49.1%) and Kingella kingae (20.0%). An average transphyseal lesion represented 8.9% of the total physeal surface, and lesions comprised more than 7% of the physeal cross-sectional area in 51% of cases. Our study revealed that pediatric THO was more frequent than commonly thought. Transphyseal lesions were frequently above this 7% cut-off, which is of paramount importance since subsequent growth is more likely to be disturbed when more than 7% of the physeal cross-sectional area is injured. THO also affected children older than 18 months, an age at which transphyseal arterial blood supply to the epiphysis is believed to have disconnected. This finding suggests another pathophysiological reason for the transphyseal diffusion of infection, a topic deserving further studies and greater understanding. Full article

Introduction: Osteoarticular infections (OAIs) constitute serious paediatric conditions that may cause severe complications. Identifying the causative organism is one of the mainstays of the care process, since its detection will confirm the diagnosis, enable adjustments to antibiotic therapy and thus optimize outcomes. Two bacteria account for the majority of OAIs before 16 years of age: Staphylococcus aureus is known for affecting the older child, whereas Kingella kingae affects infants and children younger than 4 years old. We aimed to better define clinical characteristic and biological criteria for prompt diagnosis and discrimination between these two OAI. Materials and methods: We retrospectively studied 335 children, gathering 100 K. kingae and 116 S. aureus bacteriologically proven OAIs. Age, gender, temperature at admission, involved bone or joint, and laboratory data including bacterial cultures were collected for analysis. Comparisons between patients with OAI due to K. kingae and those with OAI due to S. aureus were performed using the Mann–Whitney and Kruskal–Wallis tests. Six cut-off discrimination criteria (age, admission’s T°, WBC, CRP, ESR and platelet count) were defined, and their respective ability to differentiate between OAI patients due to K. kingae versus those with S. aureus was assessed by nonparametric receiver operating characteristic (ROC) curves. Results: Univariate analysis demonstrated significant differences between the two populations for age of patients, temperature at admission, CRP, ESR, WBC, and platelet count. AUC assessed by ROC curves demonstrated an exquisite ability to discriminate between the two populations for age of the patients; whereas AUC for CRP (0.79), temperature at admission (0.76), and platelet count (0.76) indicated a fair accuracy to discriminate between the two populations. Accuracy to discriminate between the two subgroups of patients was considered as poor for WBC (AUC = 0.62), and failed for ESR (AUC = 0.58). On the basis of our results, the best model to predict K. kingae OAI included of the following cut-offs for each parameter: age < 43 months, temperature at admission < 37.9 °C, CRP < 32.5 mg/L, and platelet count > 361,500/mm³. Conclusions: OAI caused by K. kingae affects primarily infants and toddlers aged less than 4 years, whereas most of the children with OAI due to MSSA were aged 4 years and more. Considering our experience on the ground, only three variables were very suggestive of an OAI caused by K. kingae, i.e., age of less than 4 years, platelet count > 400,000, and a CRP level below 32.5 mg/L, whereas WBC and ESR were relatively of limited use in clinical practice. Full article

As a result of the increasing use of improved detection methods, Kingella kingae, a Gram-negative component of the pediatric oropharyngeal microbiota, is increasingly appreciated as the prime etiology of septic arthritis, osteomyelitis, and spondylodiscitis in children aged 6 to 48 months. The medical literature was reviewed to summarize the laboratory methods required for detecting the organism. Kingella kingae is notoriously fastidious, and seeding skeletal system samples onto solid culture media usually fails to isolate it. Inoculation of synovial fluid aspirates and bone exudates into blood culture vials enhances Kingella kingae recovery by diluting detrimental factors in the specimen. The detection of the species has been further improved by nucleic acid amplification tests, especially by using species-specific primers targeting Kingella kingae’s rtxA, groEL, and mdh genes in a real-time PCR platform. Although novel metagenomic next-generation technology performed in the patient’s plasma sample (liquid biopsy) has not yet reached its full potential, improvements in the sensitivity and specificity of the method will probably make this approach the primary means of diagnosing Kingella kingae infections in the future. Full article

(1) Background: We aim to identify clinical and laboratorial parameters to distinguish Kingella kingae from pyogenic septic arthritis (SA). (2) Methods: A longitudinal, observational, single-centre study of children < 5 years old with microbiological positive SA admitted to a paediatric hospital from 2013–2020 was performed. Clinical and laboratorial data at admission and at 48 h, as well as on treatment and evolution, were obtained. (3) Results: We found a total of 75 children, 44 with K. kingae and 31 with pyogenic infections (mostly MSSA, S. pneumoniae and S. pyogenes). K. kingae affected younger children with low or absent fever, low inflammatory markers and a favourable prognosis. In the univariate analyses, fever, septic look, CRP and ESR at admission and CRP at 48 h were significantly lower in K. kingae SA. In the multivariate analyses, age > 6 months ≤ 2 years, apyrexy and CRP ≤ 100 mg/L were significative, with an overall predictive positive value of 86.5%, and 88.4% for K. kingae. For this model, ROC curves were capable of differentiating (AUC 0.861, 95% CI 0.767–0.955) K. kingae SA from typical pathogens. (4) Conclusions: Age > 6 months ≤ 2 years, apyrexy and PCR ≤ 100 mg/L were the main predictive factors to distinguish K. kingae from pyogenic SA < 5 years. These data need to be validated in a larger study. Full article

Nowadays, Kingella kingae is considered an important cause of primary spinal infections in children aged between 6 and 48 months. The presentation of the disease is often characterized by mild clinical features and a moderate biological inflammatory response, requiring a high index of suspicion. Performing magnetic resonance imaging (MRI) and obtaining an oropharyngeal specimen and subjecting it to a K. kingae-specific nucleic acid amplification test are recommended for its diagnosis. Most patients respond promptly to conservative treatment after administration of antibiotic therapy, which is prolonged for up to 3 months according to the individual clinical and biological response. Invasive surgical procedures are not required except for children who do not improve with antibiotic treatment, develop signs of cord compression, or if the presence of atypical microorganisms is suspected. Kingella kingae spinal infections usually run an indolent and benign clinical course, living no permanent sequelae. Full article

The emergence of Kingella kingae as an important etiology of pediatric osteoarticular infections over the past three decades has led to significant research efforts focused on understanding the pathogenicity of this fastidious Gram-negative bacterium. This work has uncovered multiple virulence factors that likely play key roles in the ability of the organism to colonize the upper respiratory tract, breach the epithelial barrier, and disseminate to distal sites of infection. Herein the current body of knowledge about K. kingae virulence factors is reviewed in the context of K. kingae disease pathogenesis. The work summarized here has identified multiple targets for therapeutic intervention as well as potential vaccine antigens. Full article

With the appreciation of Kingella kingae as a prime etiology of osteoarticular infections in young children, there is an increasing interest in the pathogenesis of these diseases. The medical literature on K. kingae’s colonization and carriage was thoroughly reviewed. Kingella kingae colonizes the oropharynx after the second life semester, and its prevalence reaches 10% between the ages of 12 and 24 months, declining thereafter as children reach immunological maturity. Kingella kingae colonization is characterized by the periodic substitution of carried organisms by new strains. Whereas some strains frequently colonize asymptomatic children but are rarely isolated from diseased individuals, others are responsible for most invasive infections worldwide, indicating enhanced virulence. The colonized oropharyngeal mucosa is the source of child-to-child transmission, and daycare attendance is associated with a high carriage rate and increased risk of invasive disease. Kingella kingae elaborates a potent repeat-in-toxin (RTXA) that lyses epithelial, phagocytic, and synovial cells. This toxin breaches the epithelial barrier, facilitating bloodstream invasion and survival and the colonization of deep body tissues. Kingella kingae colonization and carriage play a crucial role in the person-to-person transmission of the bacterium, its dissemination in the community, and the pathogenesis of invasive infections. Full article

The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms of infective endocarditis. K. kingae secretes an RtxA cytotoxin, which is involved in the development of clinical infection and belongs to an ever-growing family of cytolytic RTX (Repeats in ToXin) toxins secreted by Gram-negative pathogens. All RTX cytolysins share several characteristic structural features: (i) a hydrophobic pore-forming domain in the N-terminal part of the molecule; (ii) an acylated segment where the activation of the inactive protoxin to the toxin occurs by a co-expressed toxin-activating acyltransferase; (iii) a typical calcium-binding RTX domain in the C-terminal portion of the molecule with the characteristic glycine- and aspartate-rich nonapeptide repeats; and (iv) a C-proximal secretion signal recognized by the type I secretion system. RTX toxins, including RtxA from K. kingae, have been shown to act as highly efficient ‘contact weapons’ that penetrate and permeabilize host cell membranes and thus contribute to the pathogenesis of bacterial infections. RtxA was discovered relatively recently and the knowledge of its biological role remains limited. This review describes the structure and function of RtxA in the context of the most studied RTX toxins, the knowledge of which may contribute to a better understanding of the action of RtxA in the pathogenesis of K. kingae infections. Full article