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Evaluation of the Broad-Range PCR/ESI-MS Technology in Blood Specimens for the Molecular Diagnosis of Bloodstream Infections.

Jordana-Lluch E, Giménez M, Quesada MD, Rivaya B, Marcó C, Domínguez MJ, Arméstar F, Martró E, Ausina V - PLoS ONE (2015)

Bottom Line: When discrepancies were found, clinical records and results from other cultures were taken into consideration (clinical infection criterion).The overall positive and negative agreement of IRIDICA with blood culture in the analysis by specimen was 74.8% and 78.6%, respectively, rising to 76.9% and 87.2% respectively, when compared with the clinical infection criterion.When ICU patients were analyzed separately, sensitivity, specificity, positive and negative predictive values compared with blood culture were 83.3%, 78.6%, 33.9% and 97.3% respectively, and 90.5%, 87.2%, 64.4% and 97.3% respectively, in comparison with the clinical infection criterion.

View Article: PubMed Central - PubMed

Affiliation: Microbiology Service, Germans Trias i Pujol University Hospital, Department of Genetics and Microbiology, Autonomous University of Barcelona, Badalona, Spain; CIBER in Respiratory Diseases (CIBERES), Madrid, Spain; Health Sciences Research Institute (IGTP), Badalona, Spain.

ABSTRACT

Background: Rapid identification of the etiological agent in bloodstream infections is of vital importance for the early administration of the most appropriate antibiotic therapy. Molecular methods may offer an advantage to current culture-based microbiological diagnosis. The goal of this study was to evaluate the performance of IRIDICA, a platform based on universal genetic amplification followed by mass spectrometry (PCR/ESI-MS) for the molecular diagnosis of sepsis-related pathogens directly from the patient's blood.

Methods: A total of 410 whole blood specimens from patients admitted to Emergency Room (ER) and Intensive Care Unit (ICU) with clinical suspicion of sepsis were tested with the IRIDICA BAC BSI Assay (broad identification of bacteria and Candida spp.). Microorganisms grown in culture and detected by IRIDICA were compared considering blood culture as gold standard. When discrepancies were found, clinical records and results from other cultures were taken into consideration (clinical infection criterion).

Results: The overall positive and negative agreement of IRIDICA with blood culture in the analysis by specimen was 74.8% and 78.6%, respectively, rising to 76.9% and 87.2% respectively, when compared with the clinical infection criterion. Interestingly, IRIDICA detected 41 clinically significant microorganisms missed by culture, most of them from patients under antimicrobial treatment. Of special interest were the detections of one Mycoplasma hominis and two Mycobacterium simiae in immunocompromised patients. When ICU patients were analyzed separately, sensitivity, specificity, positive and negative predictive values compared with blood culture were 83.3%, 78.6%, 33.9% and 97.3% respectively, and 90.5%, 87.2%, 64.4% and 97.3% respectively, in comparison with the clinical infection criterion.

Conclusions: IRIDICA is a promising technology that offers an early and reliable identification of a wide variety of pathogens directly from the patient's blood within 6h, which brings the opportunity to improve management of septic patients, especially for those critically ill admitted to the ICU.

No MeSH data available.


Related in: MedlinePlus

Flowchart depicting the study design.
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pone.0140865.g001: Flowchart depicting the study design.

Mentions: This was an observational prospective study including a total of 405 patients admitted to the ICU or ER (median age 66 years, range 16–101; 246 male and 161 female) with a suspicion of sepsis according to the American College of Chest Physicians/Society of Critical Care Medicine (ACCP/SCCM) criteria [9], and enrolled between September 2012 and March 2013 at a tertiary care center in Spain (Fig 1). For each patient, one extra whole blood specimen was collected in an EDTA tube under aseptic conditions at the same time as the inoculation of the blood culture for routine microbiological testing (at the onset of fever or other clinical signs of sepsis). For five patients, a blood specimen from two different sepsis episodes was included adding up to 410 specimens. The result of the paired blood culture for each specimen was recorded. Over the study period, a blood specimen was obtained for 222 ICU patients (median age 57.7 years, range 16–83; 138 male, 82 female), which were all tested by IRIDICA. These corresponded to 32 specimens with a paired positive blood culture and 190 with a paired negative blood culture. In order to further assess the ability of the technology for identifying a wider range of pathogens, we also included 188 specimens with paired positive blood culture from ER patients (median 71.5 years, range 20–101; 110 male, 80 female), as this clinical unit is the source of 60% of blood cultures sent to the Microbiology laboratory. Those patients in which skin contaminants were identified by blood culture were excluded from this study (n = 56 cases with 59 microorganisms isolated from a single positive culture bottle with coagulase-negative staphylococci (n = 46), Streptococcus spp. (n = 5), Micrococcus spp. (n = 3), Corynebacterium spp. (n = 2), Bacillus spp. (n = 1), Propionibacterium spp. (n = 1), and Stenotrophomonas maltophilia (n = 1)). Whole blood specimens were stored at -20°C until testing at Ibis Biosciences.


Evaluation of the Broad-Range PCR/ESI-MS Technology in Blood Specimens for the Molecular Diagnosis of Bloodstream Infections.

Jordana-Lluch E, Giménez M, Quesada MD, Rivaya B, Marcó C, Domínguez MJ, Arméstar F, Martró E, Ausina V - PLoS ONE (2015)

Flowchart depicting the study design.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608784&req=5

pone.0140865.g001: Flowchart depicting the study design.
Mentions: This was an observational prospective study including a total of 405 patients admitted to the ICU or ER (median age 66 years, range 16–101; 246 male and 161 female) with a suspicion of sepsis according to the American College of Chest Physicians/Society of Critical Care Medicine (ACCP/SCCM) criteria [9], and enrolled between September 2012 and March 2013 at a tertiary care center in Spain (Fig 1). For each patient, one extra whole blood specimen was collected in an EDTA tube under aseptic conditions at the same time as the inoculation of the blood culture for routine microbiological testing (at the onset of fever or other clinical signs of sepsis). For five patients, a blood specimen from two different sepsis episodes was included adding up to 410 specimens. The result of the paired blood culture for each specimen was recorded. Over the study period, a blood specimen was obtained for 222 ICU patients (median age 57.7 years, range 16–83; 138 male, 82 female), which were all tested by IRIDICA. These corresponded to 32 specimens with a paired positive blood culture and 190 with a paired negative blood culture. In order to further assess the ability of the technology for identifying a wider range of pathogens, we also included 188 specimens with paired positive blood culture from ER patients (median 71.5 years, range 20–101; 110 male, 80 female), as this clinical unit is the source of 60% of blood cultures sent to the Microbiology laboratory. Those patients in which skin contaminants were identified by blood culture were excluded from this study (n = 56 cases with 59 microorganisms isolated from a single positive culture bottle with coagulase-negative staphylococci (n = 46), Streptococcus spp. (n = 5), Micrococcus spp. (n = 3), Corynebacterium spp. (n = 2), Bacillus spp. (n = 1), Propionibacterium spp. (n = 1), and Stenotrophomonas maltophilia (n = 1)). Whole blood specimens were stored at -20°C until testing at Ibis Biosciences.

Bottom Line: When discrepancies were found, clinical records and results from other cultures were taken into consideration (clinical infection criterion).The overall positive and negative agreement of IRIDICA with blood culture in the analysis by specimen was 74.8% and 78.6%, respectively, rising to 76.9% and 87.2% respectively, when compared with the clinical infection criterion.When ICU patients were analyzed separately, sensitivity, specificity, positive and negative predictive values compared with blood culture were 83.3%, 78.6%, 33.9% and 97.3% respectively, and 90.5%, 87.2%, 64.4% and 97.3% respectively, in comparison with the clinical infection criterion.

View Article: PubMed Central - PubMed

Affiliation: Microbiology Service, Germans Trias i Pujol University Hospital, Department of Genetics and Microbiology, Autonomous University of Barcelona, Badalona, Spain; CIBER in Respiratory Diseases (CIBERES), Madrid, Spain; Health Sciences Research Institute (IGTP), Badalona, Spain.

ABSTRACT

Background: Rapid identification of the etiological agent in bloodstream infections is of vital importance for the early administration of the most appropriate antibiotic therapy. Molecular methods may offer an advantage to current culture-based microbiological diagnosis. The goal of this study was to evaluate the performance of IRIDICA, a platform based on universal genetic amplification followed by mass spectrometry (PCR/ESI-MS) for the molecular diagnosis of sepsis-related pathogens directly from the patient's blood.

Methods: A total of 410 whole blood specimens from patients admitted to Emergency Room (ER) and Intensive Care Unit (ICU) with clinical suspicion of sepsis were tested with the IRIDICA BAC BSI Assay (broad identification of bacteria and Candida spp.). Microorganisms grown in culture and detected by IRIDICA were compared considering blood culture as gold standard. When discrepancies were found, clinical records and results from other cultures were taken into consideration (clinical infection criterion).

Results: The overall positive and negative agreement of IRIDICA with blood culture in the analysis by specimen was 74.8% and 78.6%, respectively, rising to 76.9% and 87.2% respectively, when compared with the clinical infection criterion. Interestingly, IRIDICA detected 41 clinically significant microorganisms missed by culture, most of them from patients under antimicrobial treatment. Of special interest were the detections of one Mycoplasma hominis and two Mycobacterium simiae in immunocompromised patients. When ICU patients were analyzed separately, sensitivity, specificity, positive and negative predictive values compared with blood culture were 83.3%, 78.6%, 33.9% and 97.3% respectively, and 90.5%, 87.2%, 64.4% and 97.3% respectively, in comparison with the clinical infection criterion.

Conclusions: IRIDICA is a promising technology that offers an early and reliable identification of a wide variety of pathogens directly from the patient's blood within 6h, which brings the opportunity to improve management of septic patients, especially for those critically ill admitted to the ICU.

No MeSH data available.


Related in: MedlinePlus