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
Table 1: Demographic and laboratory data of the patients with COM
n
Age in
years
No. of isolated
pathogens
Isolation of pathogen
Sex WBCc ESR CRP Path Site of COM Single Multiple Sinus-track culture Bone culture
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
6
4
13
5
7
11
8
12
6
5
2
13
6
9
13
9
15
8
9
7
10
M
F
M
F
M
M
M
M
M
F
F
M
M
F
M
M
M
F
M
M
M
7,100
22,800
12,200
7,100
14,400
11,300
14,000
6,950
14,300
16,900
13,100
6,660
9,270
15,900
5,900
16,600
9,680
8,700
7,400
9,300
6,900
86
39
86
60
92
52
84
79
28
92
66
41
112
86
28
71
125
72
58
79
61
196
81
91
11
110
186
168
68
40
27
208
210
72
134
128
277
295
69
154
131
78
(+)
(+)
(+)
(+)
(+)
(+)
(+)
Not done
(+)
(+)
(+)
(-)
(-)
(+)
(+)
(+)
(+)
Not done
(+)
(+)
(+)
Tibia
Tibia
Tibia
Humerus
Tibia
Tibia+Fibula
Tibia
Femur
Tibia
Tibia
Tibia
Femur
Tibia+Fibula
Tibia
L4 Vertebra
Tibia
Tibia+Fibula
Tibia
Femur
Tibia
Tibia
(+)
(+)
(-)
(+)
(+)
(+)
(+)
(+)
(+)
(+)
(-)
(+)
(+)
(-)
(+)
(+)
(+)
(+)
(+)
(+)
(-)
(-)
(-)
(+)
(-)
(-)
(-)
(-)
(-)
(-)
(-)
(+)
(-)
(-)
(+)
(-)
(-)
(-)
(-)
(-)
(-)
(+)
K. pneumoniae
P. mirabilis
E.coli + MRSA
P. aeruginosa
MSSA
MSSA
MSSA
MRS
MSSA
MSSA
MSSA+ E.coli
MSSA
P. aeruginosa
Strep.pyogenes + P.penneri
MSSA
MSSA
MRSA
MSS
E.coli
E.faecalis
MSSA + E.coli
MRSA
P. mirabilis
E.coli + MRSA
P. aeruginosa
MSSA
MSSA
No growth
MRS
MSSA
MSSA
MSSA
MRSA
P. aeruginosa
MSSA
MSSA
MSSA
MRSA
K. pneumoniae
E.coli
MRS
MSSA
M: Male, F: Female, WBCc: Total white blood cell count, ESR: Erythrocyte sedimentation rate, CRP: C-reactive protein, Path: Pathologyresult,
COM: Chronic osteomyelitis, MRS: Methicillin resistant coagulase-negative staphylococci, MRSA: Methicillin resistant S. aureus,
MSSA: Methicillin sensitive S. aureus
being administered. This might also explain the
fact that early sinus-track cultures more commonly
contained the operative pathogen than those obtained
from our patients later in course of their COM.
Our patient population was unique in that all of
our patients had post-traumatic or postoperative
osteomyelitis. Other studies included patients who
had hematogenous osteomyelitis or osteomyelitis due
to contiguous spread, such as secondary to diabetic
or decubitus ulcers [18, 21] . In our study, the material for
culture was obtained under carefully circumscribed
conditions. For example, antibiotics were discontinued
at least 48 hours before samples were taken, but other
authors have not discussed whether they discontinued
antibiotics before obtaining material for culture or
not [25] .
Our data indicated that, S. aureus was the most
common pathogen causing COM in our patient
population and this is similar to other studies; however,
CNS, P. aeruginosa and various Enterobacteriaceae were
the agents responsible for osteomyelitis. In this study,
no anerobic infection was encountered. Nevertheless,
anerobic infections of bone are uncommon [17] , but the
failure of organisms to grow on anaerobic culture of
material obtained does not rule out the presence of
anerobic pathogens. This may indicate a failure in
our culture technique. However, tuberculosis should
be suspected if routine aerobic and anerobic cultures
from a flowing sinus or bone do not support growth of
any pyogenic bacteria. An important finding was that
mycobacteria can sometimes be isolated from sinus-track
culture when bone culture, histopathology and clinical
examination have all failed to confirm the diagnosis.
Despite the strengths of our study, a few limitations
deserve mention. For example, its retrospective nature,
the modest sample size and selection bias of patients.
Secondary COM is relatively uncommon in childhood
and because of this reason our sample size may not
be large enough to detect a statistically significant
difference between sinus-track and bone cultures.
But it has revealed that bone cultures are essential to
determine the real causative pathogen in COM.
CONCLUSION
Osteomyelitis is a major medical problem in most
countries and a very expensive disease for patient
and society because of the involved costs of diagnosis,
inpatient and outpatient treatment, rehabilitation,
lost productivity, and sequelae. This study shows
that if treatment of chronic osteomyelitis (COM) was
planned according to the microbiological analysis
of material from the sinus-track, it may not result in
recovery every time. We found approximately 48%
concordance between sinus-track and bone cultures.
In other words, antimicrobial therapy guided by
antibiograms of bacteria isolated from sinus-track
would be inappropriate in 52% of patients with COM
and result in treatment failure.