Child Throat Bacteria Also Found in Joint Infections

Using sensitive diagnostics, researchers have found that the presence of the Kingella kingae in children's throats was strongly linked to bone and joint infection with the same bacterium.

Previously, most bone and joint bacterial infections in children were thought to be caused by Staphylococcus, Streptococcus, or Haemophilus influenzae Type B bacteria, and were treated with long-term antibiotics and/or surgery. Over the last years, new highly sensitive techniques have allowed more precise identification of the bacteria responsible for these infections.

The study – a collaboration between two pediatric university hospital centers in Montreal, Canada, and Geneva, Switzerland – included 77 children aged 6 months to 4 years of age admitted for suspected bone or joint infection and 286 controls. Of the suspected infections, 65 children had confirmed bone or joint infection.

"Using improved diagnostic methods, our study found that the vast majority of children younger than 4 years old suffering from a bone or joint infection were infected by Kingella kingae bacteria," stated Dr. Jocelyn Gravel, of the Mother & Child University Hospital Center Sainte-Justine, University of Montreal (Montréal, Quebec, Canada), "More importantly, we discovered that 70% of children who had a bone/joint infection carried these bacteria in their throats, while it is uncommon in uninfected children (only 6%)."

These results are especially important as the proportion of unknown pathogen was very high in previous studies. Now, using innovative diagnosis methods, this study demonstrated the K. kingae is not uncommon. Rather, it is by far the most common pathogen for bone or joint infection in children.

"Based on this study, we plan to change the way we investigate children at risk of bone/joint infection, because the identification of K. kingae in the throat of a child with a suspected bone infection will point towards K. kingae as the culprit. This may decrease the number of other tests performed to identify the pathogen."

The authors note that it was a small study and further studies are needed. In a related commentary in CMAJ, Drs. Romain Basmaci and Stéphane Bonacorsi, Louis-Mourier Hospital (Colombes, France), caution that, although the findings of the study show a strong association between throat infection of K. kingae and bone/joint infection, "with a carriage rate among healthy children as high as 10% in some countries, relying on oropharyngeal detection as a proxy for diagnosis in the case of a joint infection would result in a high false-positive diagnosis."

The study, by Gravel J et al, and the above-mentioned related commentary, were published September 5, 2017, in CMAJ (Canadian Medical Association Journal).

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Mother & Child University Hospital Center Sainte-Justine