1. Andrea Guyot Consultant Microbiologist
Educational Workshops 2013
Bone and Joint Infections
UTI and prosthetic joint infections
Andrea Guyot
Consultant Microbiologist

2. 77 y female patient: May 2011 L TKR insertion
1995 right TKR
left TKR
ASA3, BMI 33, MRSA neg
comorbidities:
Leg ulcers on shins with recurrent cellulitis
Recurrent UTIs (last UTI in April 2011 on pre-assessment with fully sensitive E. coli)
Chronic anaemia (Hb 10, iron 7)

3. What are known risk factors for prosthetic joint infections?

4. Admission for vertigo
Diagnosis of benign paroxymal positional vertigo treated with cinnarizine
Urine: 1450 WBC (culture isolates identified by MaldiTOF):
Klebsiella
res amoxicilin only
plus
Enterobacter aerogenes
res: Augmentin, cefalexin
sens: cipro, trimethroprim, gentamicin, meropenem, cefpodoxime
Blood: iron deficiency anaemia with iron 3 umol/l and transferrin 2.26g/l
Platelets 320, WBC 9.9, Hb 8.9, CRP 49

5. Home discharge
Discharge home on trimethroprim (to be taken until )
On readmission for swollen hot L TKR
WBC 10, CRP 203, ESR 21, Hb 7.5, platelets 23
MSU: 94 WBC; Enterobacter aerogenes
res: Augmentin, cefalexin
sens: cipro, gent, cefpodoxime, trimethroprim

6. 13.12.2011 Synovial fluid 3720 WBC, 73% PMN
Citrobacter koseri (identified by MaldiTOF)
res: Augmentin, cefuroxime
sens: cipro, gent , cefpodoxime

7. What are the sensitivities of investigations on synovial fluid?

8. Risk of UTI for PJI Maderazo E et al
Risk of UTI for PJI Maderazo E et al. Late infections of total joint prosthesis. Clin. Orthop Relat Res 1988;229:
Incidence of PJI=1%
Risk for haematogenous seeding 1:5= 0.2%
Risk for seeding from UTI = 13% of 0.2%=0.026%= 26:100000
= approximately 1:4000 arthroplasties get infected by haematogenous seeding from UTI

9. st stage of revision
Removal of TKR and implantation of Vancogenx spacer with Palacos R&G (gentamicin) cement on prophylactic dose of teicoplanin 600mg and 120mg gentamicin
Meropenem 1g tds started postop
5 periprosthetic tissues grow Citrobacter kosei
sens: meropenem, gentamicin, ciprofloxacin

10. How many periprosthetic tissues are required for DIAGNOSIS of PJI and what is the performance?

11. Which antibiotic would you choose for citrobacter?

12. post-op
Platelets 13, Hb 5.6, prothrombin time 15 sec, PT ratio 1.3
Haematological diagnosis:
Thrombotic thrombocytopenic purpura
Transferred to a specialist hospital for Rituximab and plasma exchange
The features in the blood tests just prior to Christmas 2011 are absolutely classic with clear evidence of haemolysis, a grossly raised LDH of 1545 iu/L and no discernible ADAMS TS13 evident in her peripheral bloods. The low platelet count was because of the inability of the enzyme ADAMS TS13 to cut von Willebrand’s factor off her endothelial cells and therefore platelets were deposited in the vessel as a consequence. The most important thing in a patient like this is that you do not receive a platelet transfusion, which has been associated with fatal thrombotic stroke.
Fortunately she was transferred to the specialist hospital for plasmaphoresis with FFP, which acts as a source of the missing enzyme ADAMS TS13 and also Rituximab therapy to destroy the B lymphocytes which produce the antibody in the first place.

13. 25.1.2012 Return from specialist hospital on meropenem 1g tds:
MRSA in nose, not in groin
Mupirocin and chlorhexidine washes prescribed
CRP 7.8, WBC 8, HB 10.5, platelets 300
going home on on oral ciprofloxacin 750mg bd until

14. How long should antibiotics be given between 2 stages of revision?

15. 26.4.2012 Preassessment: MRSA neg,
CRP 4, ESR 6, WBC 3.4, platelets 240, Hb 12.4
MSU 64 WBC, no growth

16.
2nd stage revision arthroplasty on flucloxacillin and gentamicin
Joint fluid and tissues on enrichment culture: no growth

17. Follow up Discharge home 21.5.2012
ESR 21, CRP 5.4, WBC 3.4, platelets 208
Platelets 360, Hb 10.9
Follow up on (at 10 months after 2nd stage)
No sinus formation
CRP <4, ESR 16, WBC 5.7, Hb 11.9
Oxford score 22 (max=50, good revision outcome >30) with pain score 1 (=mild)
ROM 120 C with lateral ligament laxity
Xray: no loosening