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• Life long suppressive AB:
elderly and fragi-
le patients, immunosuppressive patients,
radiotherapy.
In case of non growing pathogens: recent AB
and clinically inapparent infection (type I
Tsukayama-Segawa) routine microbiological
cultures are performed but samples are sent to
the molecular laboratory
(Prof. J.L. Gala,
UCL)
1
.
The DNA extraction procedure, polymerase
chain reaction (PCR) and molecular species
identification are performed to identify
sequences corresponding to the presence of
Gram+ and Gram-bacteria (picture 4).
The authors confirm the previous data repor-
ting the persistence of bacterial DNA in
samples collected from septic arthritis up to
22 days after antibiotics initiation [11].
Each identification technique has its advan-
tages and disadvantages (Table 1).
Even with specific treatment, the literature
demonstrates a recurrence rate of infection
after 2 stages reimplantation of 20% [12, 13].
The surgeon must individualize the surgical
and non surgical treatment by comparing the
likehood of success to the risk and morbidity
for a specific infection in a specific patient.
So there is a need to identify patient with a
increased risk of recurrence and susceptibili-
ty to new infection. The Mac Pherson’s sta-
ging for periprosthetic infection is one of the
procedures to develop infection prevention
protocol [14].
A BELGIAN STUDY AND GUIDELINES FOR AN INFECTED TKP
289
1
J.-L. GALA, center for Applied Molecular Technology, 30.46 Clos Chapelle-aux-champs. B 1200 Bruxelles, Belgium.
Microbiological methods
Molecular analysis
False negative results: previous ABtherapy
Unaffected by ABtherapy
Small inoculum
False positive: exogenous bacterial DNA
Prolonged transport time
Disadvantage: cost!
Picture 3 : We prefer mostly, for the impor-
tant reconstructions of soft tissues, a free
flap of latissimus dorsi rather than a pedicle
flap of gastrocnemius.
Picture 4 : Comparison of DNA sequences to
a database for the identification of germs.
Table 1