BESS PJI Guidelines - 8

S8
ciproﬂoxacin in a patient taking other medications that
prolong the QT interval.
Antimicrobial stewardship is an important overarching principle governing the choice of antimicrobial
agent. Although it is common practice to employ
broad spectrum agents immediately after surgical sampling, clinicians should switch to targeted therapy with
the narrowest spectrum agent likely to be eﬀective once
susceptibilities of the causative pathogen are known.
The surgeon should discuss the patient, organism and
antibiotics with a specialist in clinical infection as part
of the multidisciplinary management.
3.1.4 Dose of antimicrobial agents. Traditionally, treatment
of bone and joint infection is considered to require high
dose antibiotic therapy. This probably reﬂects the variation between agents in bone penetration. Beta-lactam
antibiotics have relatively poor bone penetration and
therefore, in order to achieve adequate levels at the site
of infection, high dose therapy is required. Conversely,
there are some agents such as doxycycline and rifampicin
which achieve adequate concentration in bone with
standard dosing regimens.
Periprosthetic joint infections are commonly characterized by the presence of bioﬁlm-associated sessile bacteria in a stationary growth phase. This markedly
increases the concentration of antibiotic required at
the site of infection. For a minority of agents, therapeutic drug monitoring is used to inform the most
appropriate dosage.
3.1.5 Route of antimicrobial administration. Although immediate post-operative antibiotic therapy is most commonly administered intravenously, there is increasing
conﬁdence in an early switch to oral therapy in the
management of bone and joint infection.14 Its eﬀectiveness relies on the selection of agents with adequate oral
bioavailability and good bone penetration, as well as
robust mechanisms to promote good adherence to therapy. Where these factors cannot be ensured, it may be
appropriate to continue IV therapy. The advantages of
oral therapy include reduced risk of complications associated with intravenous access devices, earlier discharge
from hospital and reduced costs as compared to IV
therapy.
3.1.6 Duration of antimicrobial therapy. Duration of therapy is poorly deﬁned but inﬂuenced by several factors.
Where surgery is considered completely curative, such
as following amputation, there is probably no need for
post-operative antibiotic therapy although it is
common practice to include antibiotic cover for 24 -
48 hours. Following removal of an infected prosthetic
joint without retention of any metalware or cement
post-operatively, six weeks of systemic therapy is

Shoulder & Elbow 10(1S)

probably adequate. Evidence for this includes a recent
prospective trial in vertebral osteomyelitis which compared 12 weeks versus 6 weeks of therapy.15
For PJI managed by DAIR, observational data
relating to 112 infected arthroplasties (which included
only six upper limb joints) suggests that continuing
therapy beyond 180 days is likely to postpone but not
reduce the absolute risk of treatment failure following
cessation of therapy.16 International guidelines for
DAIR advocate pathogen-speciﬁc antibiotic durations
of 3 and 6 months post-operatively for total hip and
knee arthroplasties respectively. The guidelines suggest
that upper limb PJI should be managed as for infected
prosthetic hip joints1. The evidence and reasons for this
are limited and not all upper limb joints are similar to
hip joints. As such we recommend that shoulder and
elbow PJI treated by DAIR should receive 3 to 6
months of pathogen-speciﬁc antibiotics. The exact duration will be guided by the infection specialist, based on
surgical clearance, organisms, sensitivities and choice of
antibiotics.
3.1.7 Specific organisms
Staphylococcal infection-MSSA. Flucloxacillin is widely
considered the optimal anti-staphylococcal agent
where susceptibilities allow. The usual intravenous
dose is 2 g QDS. It has variable oral bioavailability
which limits its utility as an oral agent in PJI.
Ceftriaxone is an alternative intravenous agent for
patients with non-anaphylactic penicillin allergy and
for out-patient antimicrobial therapy (OPAT) given
the convenience of once daily dosing (usually 2 g OD).17
Where oral therapy for staphylococcal infection is
being considered, dual oral agents are preferred.
These might include ciproﬂoxacin, doxycycline or cotrimoxazole most commonly in combination with rifampicin. The latter is particularly important in metalware
associated infection managed by DAIR.
MRSA and coagulase negative staphylococci. Coagulase
negative staphylococci are frequently resistant to methicillin and, even where they appear susceptible in vitro,
their tendency to polyclonality means that they are
often treated as methicillin resistant.
For methicillin-resistant Staphylococcus aureus
(MRSA), vancomycin (with serum trough level
15-20 mg/L before the fourth dose) has long been the
standard of treatment. Teicoplanin (12 mg/Kg and
serum trough level 20-60 mg/L after a minimum of ﬁve
days of therapy) is an alternative agent used for once-daily
dosing in outpatient antimicrobial IV therapy settings.
Glycopeptide bactericidal ability and the clinical
results obtained are suboptimal, especially in retention
procedures. Alternative drugs such as daptomycin and

Table of Contents for the Digital Edition of BESS PJI Guidelines