Is Treatment With Dithiothreitol More Effective Than Sonication for the Diagnosis of Prosthetic Joint Infection?

BACKGROUND: Prosthetic joint infection (PJI) is among the most-severe complications of a total joint arthroplasty. Identification of the causal organism is of paramount importance for successful treatment, and sonication of implants may aid in this identification. Dithiothreitol (DTT) treatment has been proposed as an alternative to sonication to improve diagnosis, reduce costs, and improve reliability of the procedure, but its efficacy remains poorly characterized. QUESTIONS/PURPOSES: (1) Are DTT and sonication more sensitive and/or more specific than standard cultures of tissue samples for the diagnosis of PJI? (2) Which test (DTT or sonication) is more sensitive when the clinician does not suspect infection before surgery? (3) Which test (DTT or sonication) is more sensitive when the clinician suspects infection before surgery? METHODS: Two hundred thirty-two patients undergoing revision of a knee or hip arthroplasty were prospectively evaluated in this randomized study. Cultures were performed on five tissue samples from each patient and on fluid obtained by prosthesis treatment in patients randomly assigned to sonication (117 patients) or DTT (115 patients). The reference standard against which cultures (on tissue samples and on fluids from sonication or DTT) were compared was the Musculoskeletal Infection Society definition of PJI. RESULTS: Cultures on sonication and DTT fluids provided higher sensitivity (89% and 91%, respectively) than those on standard cultures of tissue samples (79%; p < 0.001). Among patients in whom infection was not suspected before surgery, the sensitivity of DTT was greater than that for sonication and cultures on tissue samples (100% versus 70% and 50%; p < 0.001). Among patients in whom infection was suspected before surgery, the sensitivity of DTT and sonication were not greater than that for standard cultures (89% and 94% versus 86%). CONCLUSIONS: In this randomized study, we found no difference in sensitivity between DTT and sonication for the detection of PJI, and both of those tests were more sensitive than standard tissue cultures. Thus, cultures of sonication or DTT fluid should be considered important additional tools to standard cultures for definition of PJI and should be considered together with other criteria, especially in settings where infection is not suspected before revision surgery.Level of Evidence Level I, diagnostic study.

Francisella novicida infection in a patient with pulmonary infection and pancreatitis in Italy.

Tularemia is a rare but potentially life threatening zoonotic disease caused by Francisella tularensis. F. novicida, previously considered a subspecies of F. tularensis, is currently considered a separate species. Human infections related to F. novicida are exceedingly rare but can cause morbidity and mortality in debilitated or immunocompromised individuals.A 42-year-old male presented at the hospital with vomiting, dehydration, constipation and pain in the right iliac fossa. He was first diagnosed with pancreatitis and admitted for further analysis. Chest computerized tomography scan showed the presence of parenchymal consolidation in the left upper and lower lobes of the lung with pleural effusion. Blood cultures isolated a Gram-negative coccobacillus, that was at first identified by MALDI-TOF as Francisella tularensis. Serological analysis for the detection of total antibodies against F. tularensis and Real-Time PCR targeting the gene coding for 23 kDa, resulting negative. Subsequently, PCR targeting helicases and tul4 genes, and the Regions of Difference RD1 and RD6 were performed allowing the identification of F. novicida. The isolate was further genetically characterized by whole genome sequencing (WGS).This is the first reported case of human infection caused by F. novicida in Italy.Given the rarity of human cases and the lack of specific symptoms, this pathogen is difficult to identify and the diagnosis can be extremely challenging. In this case report, despite the lack of amplification of the gene encoding for 23 kDa protein, the identification of Francisella species was achieved with the amplification of different genes and characterized by WGS.

Unyvero ITI® system for the clinical resolution of discrepancies in periprosthetic joint infection diagnosis.

OBJECTIVES: The Unyvero molecular assay was tested for the clinical resolution of discordant results, evaluating its role in prosthetic joint infection diagnosis. METHODS: Multiplex PCR was performed on 45 samples from prosthesis treatment (either sonication or dithiothreitol). Analytical performance was compared to that of biofilm culture using Musculoskeletal Infection Society criteria as gold standard. RESULTS: Unyvero and biofilm culture showed similar agreement rates compared to the gold standard (34/43 and 32/43, respectively). Both methods showed six additional identifications compatible with true infection; five positive results from biofilm culture were deemed contaminations. CONCLUSIONS: The Unyvero system showed good performances and a significantly shorter turnaround time compared to cultural methods, presenting an added value to PJI diagnosis even when performed following a composite approach.

Aeromonas veronii biovar veronii and sepsis-infrequent complication of biliary drainage placement: A case report.

BACKGROUND: Aeromonas species are uncommon pathogens in biliary sepsis and cause substantial mortality in patients with impaired hepatobiliary function. Asia has the highest incidence of infection from Aeromonas, whereas cases in the west are rare. CASE SUMMARY: We report the case of a 64-year-old woman with advanced pancreatic cancer and jaundice who manifested fever, abdominal pain, severe thrombocytopenia, anemia and kidney failure following the insertion of a percutaneous transhepatic biliary drainage. Blood culture results revealed the presence of Aeromonas veronii biovar veronii (A. veronii biovar veronii). After antibiotic therapy and transfusions, the life-threatening clinical conditions of the patient improved and she was discharged. CONCLUSION: This was a rare case of infection, probably the first to be reported in West countries, caused by A. veronii biovar veronii following biliary drainage. A finding of Aeromonas must alert clinician to the possibility of severe sepsis.

Comparison of 'time to detection' values between BacT/ALERT VIRTUO and BacT/ALERT 3D instruments for clinical blood culture samples.

OBJECTIVES: The early detection of bacteraemia and fungemia is of paramount importance to guide antimicrobial therapy in septic patients. In this study the 'time to detection' (TTD) value for the new blood culture system BacT/ALERT VIRTUO (VIRTUO) was evaluated in 1462 positive clinical bottles and compared with the TTD for 1601 positive clinical bottles incubated in the BacT/ALERT 3D system (BTA-3D). METHODS: The most representative microorganisms isolated from bottles incubated in both blood culture systems were divided into eight categories (in order of frequency): coagulase-negative staphylococci (CoNS), Escherichia coli, Enterobacteriaceae (other than E. coli), Staphylococcus aureus, Enterococcus spp, viridans group streptococci, Pseudomonas aeruginosa, and Candida spp. RESULTS: The comparison of TTD values for the two blood culture systems strongly indicated that growth of the first five groups listed above was detected earlier with VIRTUO than with BTA-3D (p < 0.05). CONCLUSIONS: The new VIRTUO blood culture system can reduce the TTD for more than 75% of isolated microorganisms.

Seroprevalence and seroincidence of herpes simplex virus type 1 and herpes simplex virus type 2 infections in a cohort of adolescents in Italy.

OBJECTIVE: The objective of this study was to improve the knowledge on the epidemiology of herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) in Italy. GOAL: The goal of this study was to study the seroincidence and seroprevalence of HSV-1 and HSV-2 infections among Italian adolescents. STUDY: We conducted a retrospective longitudinal study among 345 Italian adolescents tested for anti-HSV-1 and anti-HSV-2 on samples collected at 11 and 17 years of age. RESULTS: At 11 years of age, the HSV-1 prevalence was 51.6% and the HSV-2 prevalence was 2.6%; when 17 years old, these rates increased to 61.4% and 4.9%, respectively. The HSV-1 incidence was 1.6 per 100 person-years and was higher among females. The HSV-2 incidence was 0.4 per 100 person-years with no gender differences. CONCLUSION: HSV-1 is apparently widespread among Italian adolescents, whereas HSV-2 is limited. These data are of paramount importance when considering that HSV-1 can cause genital herpes and that HSV-2 plays a role in HIV transmission.