The Type a and Type b Polysaccharide Capsules Predominate in an International Collection of InvasiveKingella kingaeIsolates.
Kingella kingaeis an encapsulated Gram-negative bacterium and an important etiology of osteoarticular infections in young children. A recent study examining a diverse collection of carrier and invasiveK. kingaeisolates from Israel revealed four distinct polysaccharide capsule types. In this study, to obtain a global view ofK. kingaecapsule type diversity, we examined an international collection of isolates using a multiplex PCR approach. The collection contained all four previously identified capsule types and no new capsule types. Over 95% of invasive isolates in the collection were type a or type b, similar to the findings in Israel. These results suggest that the type a and type b polysaccharide capsules may have enhanced pathogenic properties or may mark clonal groups of strains with specific virulence genes. In addition, they raise the possibility that a vaccine containing the type a and type b capsules might be an effective approach to preventingK. kingaedisease.IMPORTANCEKingella kingaehas emerged as a significant cause of septic arthritis, osteomyelitis, and bacteremia in young children. A recent study examining a diverse collection ofK. kingaeisolates from Israel revealed four different polysaccharide capsule types in this species, designated types a to d. To determine the global distribution ofK. kingaecapsule types, we assembled and capsule typed an international collection ofK. kingaeisolates. The findings reported here show that the type a and type b capsules represent >95% of the invasive isolates, similar to the Israeli isolate collection, suggesting that a polysaccharide-based vaccine targeting these two capsules could be an attractive approach to preventK. kingaedisease.
Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Eric A
EA
Porsch
Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA; Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA.
Kimberly F
KF
Starr
Soroka University Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Pablo
P
Yagupsky
Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.
Joseph W
JW
St Geme
Kingella kingae; PCR; capsule typing; clinical isolates; polysaccharide capsule