Osteomyelitis/septic arthritis outbreak in children caused by K. kingae

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MINNESOTA DEPTARTMENT OF HEALTH;

Osteomyelitis/septic arthritis outbreak in children caused by K. kingae

An osteomyelitis/septic arthritis outbreak in children was caused by

Kingella kingae.

According to a study from the United States, " Kingella kingae often

colonizes the oropharyngeal and respiratory tracts of children but

infrequently causes invasive disease. In mid-October 2003, 2

confirmed and 1 probable case of K. kingae osteomyelitis/septic

arthritis occurred among children in the same 16- to 24-month-old

toddler classroom of a child care center.

" The objective of this study was to investigate the epidemiology of

K. kingae colonization and invasive disease among child care

attendees. Staff at the center were interviewed, and a site visit was

performed. Oropharyngeal cultures were obtained from the staff and

children aged 0 to 5 years to assess the prevalence of Kingella

colonization. "

" Bacterial isolates were subtyped by pulsed-field gel electrophoresis

(PFGE), and DNA sequencing of the 16S rRNA gene was performed. A

telephone survey inquiring about potential risk factors and the

general health of each child was also conducted.

" All children and staff in the affected toddler classroom were given

rifampin prophylaxis and recultured 10 to 14 days later. For

epidemiologic and microbiologic comparison, oropharyngeal cultures

were obtained from a cohort of children at a control child-care

center with similar demographics and were analyzed using the same

laboratory methods, " wrote K.M. Kiang and colleagues at the Minnesota

Department of Health in Minneapolis. "

" The main outcome measures were prevalence and risk factors for

colonization and invasive disease and comparison of bacterial

isolates by molecular subtyping and DNA sequencing. The 2 confirmed

case patients required hospitalization, surgical debridement, and

intravenous antibiotic therapy.

" The probable case patient was initially misdiagnosed; MRI 16 days

later revealed evidence of ankle osteomyelitis. The site visit

revealed no obvious outbreak source. Of 122 children in the center,

115 (94%) were cultured, " investigators said.

" Fifteen (13%) were colonized with K. kingae, with the highest

prevalence in the affected toddler classroom (9 [45%] of 20 children;

all case patients tested negative but had received antibiotics). Six

colonized children were distributed among the older classrooms; 2

were siblings of colonized toddlers.

" No staff (n=28) or children aged <16 months were colonized. Isolates

from the 2 confirmed case patients and from the colonized children

had an indistinguishable PFGE pattern. No risk factors for invasive

disease or colonization were identified from the telephone survey, "

reported Kiang.

" Of the 9 colonized toddlers who took rifampin, " continued

scientists, " 3 (33%) remained positive on reculture; an additional

toddler, initially negative, was positive on reculture. "

" The children of the control child-care center demonstrated a similar

degree and distribution of K. kingae colonization; of 118 potential

subjects, 45 (38%) underwent oropharyngeal culture, and 7 (16%) were

colonized with K. kingae. "

" The highest prevalence again occurred in the toddler classrooms. All

7 isolates from the control facility had an indistinguishable PFGE

pattern; this pattern differed from the PFGE pattern observed from

the outbreak center isolates.

" 16S rRNA gene sequencing demonstrated that the outbreak K. kingae

strain exhibited >98% homology to the ATCC-type strain, " said

researchers, " although several sequence deviations were present.

Sequencing of the control center strain demonstrated more homology to

the outbreak center strain than to the ATCC-type strain. "

The authors concluded, " This is the first reported outbreak of

invasive K. kingae disease. The high prevalence in the affected

toddler class and the matching PFGE pattern are consistent with child-

to-child transmission within the child-care center. Rifampin was

modestly effective in eliminating carriage.

DNA sequence analysis suggests that there may be considerable

variability within the species K. kingae and that different K. kingae

strains may demonstrate varying degrees of pathogenicity. "

Kiang and colleagues published their study in Pediatrics (Outbreak of

osteomyelitis/septic arthritis caused by Kingella kingae among child

care center attendees. Pediatrics, 2005;116(2):E206-E213).

For more information, contact R. Lynfield, Minnesota Dept. Health,

Sect Acute Diseases Invest & Control, 717 Delaware St., SE,

Minneapolis, MN 55414, USA.

Publisher contact information for the journal Pediatrics is: American

Academy Pediatrics, 141 North-West Point Blvd., Elk Grove Village, IL

60007-1098, USA.

Keywords: Minneapolis, Minnesota, United States, Kingella kingae,

Osteomyelitis, Outbreaks, Pediatrics, Child-Care Center, Epidemiology.

This article was prepared by Biotech Week editors from staff and

other reports. Copyright 2005, Biotech Week via NewsRx.com.

October 14, 2005