Comparison of Clinical Prediction Rules in Pre-school Aged Children With Septic Hip Arthritis Due to Different Pathogens.

BACKGROUND: Although differentiating between transient synovitis and septic hip arthritis is challenging, clinical prediction rules such as the Kocher criteria (KC) have been shown to help with the diagnosis of septic hip arthritis in children. Their performance in septic arthritis due to less virulent pathogens such as Kingella Kingae , however is unknown. We aimed to describe the performance of these clinical prediction rules in pre-school children with septic hip arthritis due to different pathogens. We hypothesised that the number of KC or modified KC met would be lower in children with septic hip arthritis caused by K. kingae , compared to those caused by Staphylococcus aureus . METHODS: In this retrospective multicentre study conducted in Australia and New Zealand between 2012-2016, we included children with confirmed septic hip arthritis due to S. aureus (n=29), K. kingae (n=20), other pathogens (n=32), and no pathogen identified (n=48). We applied the KC (temperature, weight-bearing, erythrocyte sedimentation rate, white blood cell count) and the modified KC (C-reactive protein added) and assessed their sensitivity for septic hip arthritis, using cut offs of KC ≥ 3 and modified KC ≥ 4. RESULTS: The score of the KC and the modified KC was not lower in K. kingae compared to S. aureus ( P =0.27, P =0.21). In addition, both the sensitivity for the KC ( S. aureus 18/29 (62.1%); K. kingae 12/20 (60.0%)), and for the modified KC ( S. aureus 18/29 (62.1%); K. kingae 12/20 (60.0%)) did not differ between K. kingae and S. aureus . Of all children with septic hip arthritis, the sensitivity of both the KC and modified KC were 56.6% (95%CI 47.6-65.3). CONCLUSIONS: The clinical prediction rules had comparable performance in K. kingae infections to those caused by S. aureus . Concerningly, less than 60% of the children with confirmed septic hip arthritis met the cut-off values. These prediction rules lack sensitivity to rule-out septic hip arthritis in the early assessment of pre-school aged children with acute hip pain. LEVEL OF EVIDENCE: Level III Diagnostic.

The role of Kingella kingae in pre-school aged children with bone and joint infections.

OBJECTIVES: The Pre-school Osteoarticular Infection (POI) study aimed to describe the burden of disease, epidemiology, microbiology and treatment of acute osteoarticular infections (OAI) and the role of Kingella kingae in these infections. METHODS: Information about children 3-60 months of age who were hospitalized with an OAI to 11 different hospitals across Australia and New Zealand between January 2012 and December 2016 was collected retrospectively. RESULTS: A total of 907 cases (73%) were included. Blood cultures grew a likely pathogen in only 18% (140/781). The peak age of presentation was 12 to 24 months (466/907, 51%) and Kingella kingae was the most frequently detected microorganism in this age group (60/466, 13%). In the majority of cases, no microorganism was detected (517/907, 57%). Addition of PCR to culture increased detection rates of K. kingae. However, PCR was performed infrequently (63/907, 7%). CONCLUSIONS: This large multi-national study highlights the need for more widespread use of molecular diagnostic techniques for accurate microbiological diagnosis of OAI in pre-school aged children. The data from this study supports the hypothesis that a substantial proportion of pre-school aged children with OAI and no organism identified may in fact have undiagnosed K. kingae infection. Improved detection of Kingella cases is likely to reduce the average length of antimicrobial treatment.

Human Parechovirus: an Increasingly Recognized Cause of Sepsis-Like Illness in Young Infants.

Human parechovirus (HPeV) is increasingly being recognized as a potentially severe viral infection in neonates and young infants. HPeV belongs to the family Picornaviridae and is currently divided into 19 genotypes. HPeV-1 is the most prevalent genotype and most commonly causes gastrointestinal and respiratory disease. HPeV-3 is clinically the most important genotype due to its association with severe disease in younger infants, which may partly be explained by its distinct virological properties. In young infants, the typical clinical presentation includes fever, severe irritability, and rash, often leading to descriptions of "hot, red, angry babies." Infants with severe central nervous system (CNS) infections are at an increased risk of long-term sequelae. Considering the importance of HPeV as a cause of severe viral infections in young infants, we recommend that molecular diagnostic techniques for early detection be included in the standard practice for the investigation of sepsis-like illnesses and CNS infections in this age group.

High rate of oropharyngeal Kingella kingae carriage in New Zealand children.

AIM: This study aimed to describe the burden of disease and estimated rates of oropharyngeal carriage of Kingella kingae among New Zealand children. We compared polymerase chain reaction (PCR) and culture for the detection of this microorganism with a view to further development and implementation of K. kingae PCR in Christchurch Hospital. METHODS: Oropharyngeal swabs from children between 6 and 48 months of age were analysed by culture to estimate carriage rates of K. kingae. Samples of a subgroup of children between 12 and 24 months of age were also tested by PCR. In addition, a retrospective review was performed on all cases of invasive K. kingae disease and children with osteoarticular infections. RESULTS: Oropharyngeal cultures were positive for K. kingae in specimens from 4 out of 176 children (2.3%). PCR was significantly more sensitive and by PCR, the carriage rate rose to 22.9% (95% CI = 9.4-33.9%) (n = 48). From 2005 to 2015, 17 children between 6 and 48 months of age were identified with invasive infections due to K. kingae. Seventy-four children were found to have an osteoarticular infection. Most of these were culture-negative with a microbiological diagnosis made in only 15 cases (20.3%), only one due to K. kingae. CONCLUSIONS: We found a very high carriage rate of K. kingae in New Zealand children and poor performance of K. kingae culture. It is likely that many cases of invasive K. kingae infections remain undetected. We recommend the use of a K. kingae PCR in all children under 4 years of age with a possible osteoarticular infection.