Archive for June 7, 2012

Blood culture flasks for culturing synovial fluid in prosthetic joint infections.

Clin Orthop Relat Res. Aug 2010  V.468 N.8 P.2238-43.

Font-Vizcarra L, García S, Martínez-Pastor JC, Sierra JM, Soriano A.

Department of Orthopaedics and Trauma Surgery of Hospital Clínic of Barcelona, Barcelona 08036, Spain.



Identifying the etiologic microorganism is essential to guide antimicrobial therapy in prosthetic joint infection.

QUESTIONS/PURPOSE: We (1) compared the frequency of positive cultures with synovial fluid inoculated in blood culture flasks (SF) with those of periprosthetic tissues or swabs in traditional cultures from patients with acute and chronic prosthetic joint infections (PJI) and (2) determined the sensitivity, specificity, and predictive values of the three methods.


We retrospectively reviewed 87 patients with PJIs (54 knees, 33 hips) and 63 patients with aseptic loosening (34 knees, 29 hips). Two SF, periprosthetic tissue, and swab samples were taken for culture in all 150 patients except for14 inwhom only one SF fluid sample was obtained. Synovial fluid was inoculated in blood culture flasks and periprosthetic tissue and swab samples in standard media. Positive cultures were identified with standard biochemical procedures.


SF samples were positive in 78 of 87 infected cases (90%), periprosthetic tissue samples were positive in 71 (82%), and swab samples were positive in 59 (68%). SF, periprosthetic tissue, and swab samples were positive more frequently in acute than in chronic infections (96% versus 82% for SF, 87% versus 74% for periprosthetic tissue, and 87% versus 44% for swabs). The sensitivity, specificity, and positive and negative predictive values of SF were 91, 100, 100, and 93 for acute infections and 79, 100, 100, and 88 for chronic infections, respectively.


SF samples cultured in flasks had higher sensitivity, specificity, and positive and negative predictive values for diagnosis of PJI when compared with standard tissue and swab samples. The usefulness of all samples was less in chronic than in acute infections.


Level II, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence




June 7, 2012 at 8:43 am

Interface membrane is the best sample for histological study to diagnose prosthetic joint infection.

Mod Pathol. April 2011 V.24 N.4 P.:579-84.

Bori G, Muñoz-Mahamud E, Garcia S, Mallofre C, Gallart X, Bosch J, Garcia E, Riba J, Mensa J, Soriano A.

Department of Orthopaedic and Traumatology, Hospital Clínic, University of Barcelona, Barcelona, Spain.


The objective of our study was to study which is the most accurate specimen for histological diagnosis of prosthetic joint infections (pseudocapsule or interface membrane). This is a prospective study including hip revision arthroplasties performed from January 2007 to June 2009. Specimens from pseudocapsule and from interface membrane were obtained from each patient. The histology was considered positive for infection when ≥5 neutrophils per high-power field ( × 40) were found. Definitive diagnosis of infection was considered when ≥2 cultures were positive for the same microorganism. According to the definition of infection, patients were classified in two groups: (A) patients with aseptic loosening in whom cultures obtained during surgery were negative and (B) patients with prosthetic joint infection. A total of 69 revisions were included in the study; 57 were classified in group A and12 ingroup B. In group B, the percentage of positive interface membrane histology was significantly higher than the percentage of positive pseudocapsule histology (83 vs 42%, P=0.04, Fisher’s exact test). The results suggest that periprosthetic interface membrane is the best specimen for the histological diagnosis of prosthetic joint infection.




June 7, 2012 at 8:41 am

Burkholderia cepacia bacteremia: a prospective analysis of 33 episodes.

Rev Esp Quimioter. Dec. 2011  V.24 N.4 P.209-12.

Pinilla MI, Cobos-Trigueros N, Soriano Á, Martínez JA, Zboromyrska Y, Almela M, Mensa J.

Servicio de Enfermedades Infecciosas, Hospital Clínic de Barcelona, Barcelona, Spain.



The aim of this study is to describe clinical characteristics and outcome of Burkholderia cepacia bacteraemia, susceptibility of the isolates and differences between cases from epidemic outbreaks and sporadic cases.


From 1993 to 2009, episodes of B. cepacia bacteraemia were prospectively collected in a university hospital.


A total of 33 episodes were included, of which 21 were part of two outbreaks (9 in1994 and12 in2006). Outbreak cases had a median age of 58 years, 45% had neoplasia, median length of stay until bacteraemia was 15 d (range 0-120) and 82% had received an antibiotic. The most prevalent sources of bacteraemia were catheter (48%) and unknown (33%). On the other hand, sporadic cases stayed longer until diagnosis (median 25 days versus 11, p=0.041) and showed a trend to have neoplasia more frequently (83% versus 33%, p=0.083). Susceptibility to antibiotics was varied and co-trimoxazole was the only active agent against all strains.


B. cepacia is an uncommon pathogen, which affects patients with prolonged hospitalization and severe comorbidities. The identification of more than one case in a short term of time should raise the suspicion of an outbreak.


June 7, 2012 at 8:39 am


June 2012

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