1137. Culture-Negative Septic Arthritis in Children
Session: Poster Abstract Session: Clinical Infectious Diseases: Bone and Joint, Skin and Soft Tissue
Friday, October 28, 2016
Room: Poster Hall
Background: Choice of empiric antibiotic therapy for septic arthritis (SA) children is challenging given the frequency of negative clinical cultures. Kingella kingae is an increasingly important cause of SA in young children (<5y) but rarely grows on standard agar plates. We aimed to describe culture-negative septic arthritis (CNSA) in children and assess treatment failure rates among those who received agents active (cephalosporins) and variably or not active (clindamycin, oxacillin, vancomycin) against K. kingae.

Methods: Retrospective cohort study of patients <19y hospitalized with SA at the Children’s Hospital of Philadelphia from 1/02-12/14. SA was defined as joint WBC >20,000 with associated symptoms or positive joint fluid culture; CNSA was as above with negative cultures and no pretreatment. Children with hospital transfer, ICU admission, positive Lyme serology, sickle cell disease, immunodeficiency, or hardware at the site of infection were excluded. Treatment failure was defined as change in antibiotics due to clinical worsening or lack of improvement in >48h.

Results: Of 221 SA children meeting inclusion/exclusion criteria, median age was 4.1 years, 55% were white, and 48% were female. Joint fluid culture was positive in 26% (10/39) of pretreated and 29% (52/182) of non-pretreated patients (p=0.71). MSSA (50%, 31/62) and MRSA (18%, 11/62) were the most common pathogens; K. kingae was isolated in 1 patient. 17% (31/182) of SA patients had concomitant osteomyelitis (OM), which was associated with higher CRP and ESR, and longer duration of symptoms (Table). Of the 72 patients <5y with CNSA without OM, treatment failure rates were 11% (5/44) for clindamycin, 9% (1/11) for vancomycin, 20% (1/5) for oxacillin, and 0% (0/12) for cephalosporins.

Conclusion:Patients with concomitant OM had longer duration of symptoms and higher inflammatory markers. Antibiotics with variable or no activity against K. kingae were most often used to treat CNSA in children <5y and failed in >10% of cases.



SA only (n=151)

SA + OM (n=31)

Rank sum P

Laboratory values at presentation

Blood WBC (/μL)

12600 (3800-37300)

13100 (5000-39300)


Joint fluid WBCs (/μL)

95462 (880-468000)

140500 (13125-490000)


CRP (mg/dL)

4.7 (<0.3-66.6)

8 (0.9-39.5)


ESR (mm/h)

40 (0-132)

59 (15-115)


Days of symptoms prior to admission

Any symptoms

2 (0-21)

3 (1-30)



1 (0-28)

3 (0-21)


Evangelos Spyridakis, MD1, Laura Anatale-Tardiff, MPH2, Jeffrey S. Gerber, MD, PhD3, Ari B. Frosch, MD Candidate4, Joseph W. St. Geme III, MD, FPIDS5, Eric Porsch, PhD6 and Kevin Downes, MD3, (1)Division of Infectious Diseases, The Children's Hospital of Philadelphia, Philadelphia, PA, (2)Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA, (3)Department of Pediatrics, Division of Infectious Diseases, The Children's Hospital of Philadelphia, Philadelphia, PA, (4)Children's hospital of Philadelphia, Philadelphia, PA, (5)Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA, (6)Department of Pediatrics, The CHOP Research Institute/The Children's Hospital of Philadelphia, Philadelphia, PA


E. Spyridakis, None

L. Anatale-Tardiff, None

J. S. Gerber, None

A. B. Frosch, None

J. W. St. Geme III, None

E. Porsch, None

K. Downes, Merck & Co: Investigator , Research grant
Pfizer Inc.: Investigator , Research grant

Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.