How good is the PCR for diagnosing osteoarticular infection?

Use of a broad-range polymerase chain reaction (PCR) test increases identification of Kingella kingae in osteoarticular infections, according to the findings of a newly published study. The organism has been described as a pathogen in osteoarticular infections in children, but the extent of its role has been unclear because it is difficult to grow in culture. Investigators conducted a study of 171 children who had been admitted to a pediatric hospital in France with suspected osteoarticular infection during a three-year period. Their median age was 17.9 months.

Culture was positive in 64 children, yielding K kingae in nine. Of 107 culture-negative specimens tested by 16S ribosomal DNA PCR, 15 were positive-all for Kingella. K kingae was therefore responsible for 30% of osteoarticular infections; Staphylococcus aureus (identified by culture) was the culprit in 38%. Demographic and clinical characteristics were similar in both the 24 children with K kingae osteoarticular infection diagnosed by culture and the 15 whose infection was diagnosed by PCR.

The investigators noted that, although imaging-plain radiography, ultrasonography, bone scanning, and magnetic resonance imaging-produced useful diagnostic information, findings from those studies were nonspecific (Verdier I et al: Pediatr Infect Dis J 2005;24:692).