Vol 43 # 2 June 2011 - Kma.org.kw

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The Diagnostic Value of Sinus-Track Cultures in Secondary Pediatric Chronic Osteomyelitis
June 2011
SUBJECTS AND METHODS
The medical records of 21 consecutive patients
with COM who were treated and followed up at the
Departments of Orthopedics and Traumatology and
Infectious Diseases, Dicle University Hospital and
Batman State Hospital, Turkey, between May 2005
and April 2007, were reviewed. Out of 21 patients,
the medical records of 17 patients were published in
our other study that included heterogeneous patient
groups [9] .
In this study, COM was defined as a bone infection
that was worse or had not improved clinically
or microbiologically after ≥ 10 days of evolution,
independent of the presence or absence of surgical and
/ or antimicrobial therapy. Patients were considered
to have COM, if they had one or more sinus-tracks
associated with their bone infection plus at least one of
the following: (i) positive bone culture, (ii) surgical or
histopathologic confirmation of bone infection or (iii)
radiographic evidence of bone infection. Conventional
X-ray findings were used for diagnosis principally.
When it was inadequate, other imaging techniques
such as scintigraphy and magnetic resonance imaging
were used. Nevertheless, sequential specimens taken
from the sinus-tracks and bones were not used, and
only two bone specimens were acceptable: bone biopsy
and bone marrow biopsy. Furthermore, patients with
orthopedic device were also not included in the
study.
If antibiotics were being administered, they were
discontinued at least 48 hours before material was
obtained for incubation and histological examination.
The histological findings of COM were defined as
exhibited areas of woven bone and fibrosis with large
numbers of lymphocytes, histiocytes, and plasma
cells in the absence of neutrophils [10] . In cases meeting
these criteria; we noted age, sex, laboratory results
such as white blood cell count (WBCc), erythrocyte
sedimentation rate (ESR), C-reactive protein (CRP),
involved bone, time with COM, mechanism of bone
infection, type of specimen cultured and microbiologic
identification and susceptibility pattern of organisms
grown in aerobic and anerobic atmosphere.
In the operating room, before the incision was
made, specimens were obtained from the sinus-track
for aerobic and anerobic culture. Specimens of bone
obtained from curettage, and of bone from the bed of
involved bone were obtained during the operation
for similar cultures. The bone specimen were placed
into a sterile container with non-bacteriostatic
saline and walked to microbiology laboratory by an
operating room nurse within 30 minutes. However,
the sinus-track specimens were inoculated on plates
immediately, by the bedside, without using transport
media.
The material was routinely streaked into eosinmethylene
blue agar and 5% sheep blood agar. The two
plates were incubated in air at 37 °C for 24 hours, for
aerobic microorganisms. For the isolation of anerobes,
specimens were plated onto prereduced vitamin K1
enriched Brucella blood agar, anerobic blood agar
plates containing kanamycin and vancomycin, and
anerobic blood plates containing colistin and nalidixic
acid, and then samples were inoculated into enriched
thioglycolate broth. The plated media were incubated
in a Zip-Loc plastic bag to maintain the increased
CO2 atmosphere at 37 °C and examined at 48, 96,
and 120 hours. The thioglycolate broth was incubated
for 14 days. Smears from colonies that grew under
either aerobic or anerobic conditions were stained
with Gram-stain; Gram-positive organisms were
identified by conventional techniques, Gram-negative
organisms were identified using Sceptor Systems
(Becton-Dickinson, Maryland, USA). Its susceptibility
was evaluated using disc diffusion testing performed
as recommended by the National Committee for
Clinical Laboratory Standards (NCCLS) [11] . If cultured
microorganisms were not present and the clinical
features were compatible, samples were cultured for
mycobacterium and fungus.
Isolates from the infected bone were compared
with isolates from sinus-track for each patient. Sinustrack
specimens were considered concordant with
the bone when they grew exactly the same pathogens
isolated from the bone and had identical susceptibility
patterns. Concordance was calculated for all causes
and for COM caused by S. aureus, the agent most
commonly isolated from infected bone. Single and
multiple microorganisms were isolated from tibia in
10 and four patients, respectively. On the other hand,
multiple microorganisms were not isolated from other
sites in any patients.
Descriptive and frequency statistical analyses
were performed by using the Statistical Package for
the Social Science (SPSS) for Windows, version 13.0
software (SPSS, Chicago, IL, USA).
RESULTS
In this study, 21 patients with COM were analyzed.
During this study period, 26 patients were diagnosed as
having COM, and five patients were excluded because
antibiotic treatment was not stopped 48 hours before
bone culture (n = 3), and lack of bone (n = 2). 21 patients
met the inclusion criteria; their demographic data are
detailed in Table 1. Out of 21 patients, 15 (71.4%) were
male and six (28.6%) were female with a male to female
ratio of approximately 2.5:1. The mean age of the
patients was 8.5 ± 3.8 years (range, 2 - 15 years).
The source of COM was known in all patients and
they all had secondary COM. Previous open fracture