Performance of the LightCycler SeptiFast Test M ^grade in Detecting Microbial Pathogens in Purulent Fluids

Abstract

The performance of the LightCycler SeptiFast (SF) assay was compared to that of culture methods in the detection of microorganisms in 43 purulent fluids from patients with pyogenic infections. The SF assay was more sensitive than the culture methods (86% versus 61%, respectively), irrespective of whether the infections were mono-or polymicrobial.The LightCycler SeptiFast (SF) test is a commercially available multiplex real-time PCR assay able to detect a wide range of bacterial and fungal organisms commonly involved in systemic infections (10). The SF assay has been shown to be a valuable ancillary method for the etiological diagnosis of bacteremia, sepsis, endocarditis, and more recently, periprosthetic joint infections, particularly in patients who have received antibiotics prior to diagnostic testing (1-3, 5, 6, 9, 10, 13-17). Molecular methods can allow the rapid detection of the microorganisms involved in severe pyogenic infections, thus leading to a more efficient and targeted early therapeutic intervention, which could translate into major clinical benefits for patients. To the best of our knowledge, there is no published experience on the performance characteristics of the SF assay for the detection of microorganisms in purulent fluids.A total of 43 purulent fluids obtained from 41 patients (29 male and 12 female; mean age, 64.1 years) over a period of 5 months (July to November 2010) were included in this study, as follows: 11 biliary fluid samples from patients with acute cholangitis, 7 pleural fluid samples from patients with empyema secondary to mesothelioma, lung cancer, or community-acquired and nosocomial pneumonia, 7 peritoneal fluid samples from patients with secondary peritonitis, 7 dialysis effluents from 6 patients with continuous ambulatory peritoneal dialysis (CAPD)-related peritonitis, 5 purulent liquid samples from 4 patients with intra-abdominal abscesses secondary to abdominal surgery, 4 purulent (Ͼ250 polymorphonuclear leukocytes/l) ascites fluid samples from cirrhotic patients with spontaneous bacterial peritonitis (SBP), and 2 intra-articular fluid samples from patients with acute septic arthritis. A total of 31 of the 41 patients had been treated with broad-spectrum antibiotics prior to sampling, as follows. All patients (n ϭ 11) undergoing biliary surgery, 3 patients subjected to thoracocentesis for empyema, and 3 patients undergoing laparotomy for secondary peritonitis received perioperative antimicrobial prophylaxis with amoxicillin-clavulanic. All patients with intra-abdominal abscesses and 4 patients with secondary peritonitis were empirically treated with ciprofloxacin plus metronidazole for a median of 2 days (range, 1 to 4 days) prior to specimen sampling. Four patients with secondary empyema had been treated with imipenem, imipenem plus metronidazole, or imipenem plus vancomycin for a median of 1 day prior to specimen sampling (range, 1 to 3 days). One patient with CAPD, one patient with SBP, and one patient with septic arthritis were treated with vancomycin or ceftriaxone ...

Microbiological Diagnosis of Sepsis: Polymerase Chain Reaction System Versus Blood Cultures

“…In contrast, in the case of blood culture, antibiotic administration reduced the probability of pathogen isolation by half. This finding is consistent with results reported by other researchers 8,21,33 and supports the usefulness of SeptiFast in cases where antibiotic therapy has already been started and shows its advantages over blood cultures.…”

“…However, on the whole, the results are consistent with those reported by other investigators, [8][9][10][11]21,22,28 suggesting that these findings may be extrapolated to other populations. Finally, the variability of the number of blood culture sets collected and the high rate of patients with only 2 bottles of blood samples for culture obtained could have influenced the sensitivity of the technique.…”

“…These pathogens are not always correctly treated by using initial empirical antibiotic therapy and are an important cause of treatment failure and increased mortality in patients with sepsis. 8 In particular, the detection of yeast and filamentous fungi in blood is www.ajcconline.org…”

“…6,7 Molecular methods allow rapid detection of the microorganisms involved in severe infections, leading to more efficient and more accurately targeted early therapeutic interventions, which could mean major clinical benefits for patients. 8 The LightCycler SeptiFast Test (SeptiFast, Roche Diagnostics) is a multipathogen probe-based real-time polymerase chain reaction (PCR) system targeting DNA sequences of bacteria and fungi in blood samples, and it is considered to be a potentially valuable complementary tool in the management of patients with suspected sepsis. [9][10][11] However, the superiority of the SeptiFast system to blood culture for identifying pathogens in sepsis remains unclear.…”

Comparison of conventional culture with SeptiFast real-time PCR for microbial pathogen detection in clinical specimens other than blood

“…The difference between SF and culture was not significant in the purulent exudates subgroup, although a recent paper on 43 purulent, mostly abdominal, fluids shows that SF is more sensitive than culture in patients with pyogenic infections (Sancho-Tello et al, 2011). In our study the lack of significance is probably due to the limited number of specimens evaluated.…”