Comparison of GeneXpert MRSA/SA ETA assay with semi-quantitative and quantitative cultures and nuc gene-based qPCR for detection of Staphylococcus aureus in endotracheal aspirate samples

• Published in: Antimicrobial resistance & infection control 2019-01, Vol.8 (1), p.4-4, Article 4
• Main Authors: Coppens, Jasmine, Van Heirstraeten, Liesbet, Ruzin, Alexey, Yu, Li, Timbermont, Leen, Lammens, Christine, Matheeussen, Veerle, McCarthy, Michael, Jorens, Philippe, Ieven, Margareta, Kumar-Singh, Samir, Goossens, Herman, Malhotra-Kumar, Surbhi
• Format: Article
• Language: English
• Subjects: Analysis; Antibacterial agents; Bacterial Proteins - genetics; Blood; Cepheid; COLOREX™ staph aureus; Diagnostic tests; Diagnostic Tests, Routine - methods; Disease control; DNA; Drug resistance; Genetic research; Health aspects; Humans; Infection; Intensive care; Internet; Laboratories; Methicillin; Methicillin-Resistant Staphylococcus aureus - classification; Methicillin-Resistant Staphylococcus aureus - genetics; Methicillin-Resistant Staphylococcus aureus - growth & development; Methicillin-Resistant Staphylococcus aureus - isolation & purification; Microbiology; Micrococcal Nuclease - genetics; Nosocomial infections; Pathogens; Pneumonia; Pneumonia, Ventilator-Associated; Rapid diagnostics; Real-time PCR; Real-Time Polymerase Chain Reaction; Respiratory tract; Sensitivity and Specificity; Staphylococcal Infections - diagnosis; Staphylococcal Infections - microbiology; Staphylococcus aureus; Staphylococcus aureus - classification; Staphylococcus aureus - genetics; Staphylococcus aureus - growth & development; Staphylococcus aureus - isolation & purification; Staphylococcus infections; Surveillance; Systematic review; VAP; Ventilator-associated pneumonia; Ventilators; Ventilators, Mechanical - microbiology
• ISSN: 2047-2994; 2047-2994
• DOI: 10.1186/s13756-018-0460-8

is a common cause of ventilator-associated pneumonia. Rapid and accurate detection of lower respiratory tract colonization and/or infection with may inform targeted preventive and therapeutic strategies. To investigate this, we compared semi-quantitative (SQ)-culture results from 79 endotracheal aspirates (ETA) collected from mechanically-ventilated patients, to two culture and two non-culture-based methods for detection of . ETA analyzed by routine SQ-culture on blood and colistin-nalidixic-acid agar was compared to: (i) quantitative (Q-) culture on chromogenic COLOREX™ Staph aureus; (ii) enrichment in brain-heart-infusion broth followed by plating on blood agar and COLOREX™; (iii) -based TaqMan qPCR, and (iv) GeneXpert MRSA/SA ETA assay. Of the 79 ETA samples analyzed by SQ-culture, 39 samples were positive, and 40 negative for . Two samples negative for by SQ-culture were, however, -positive by the other four methods and were considered positive. Appending these two samples as positive in the SQ-culture results, sensitivities-specificities for Q-culture, enrichment-culture, TaqMan qPCR and GeneXpert were 100-95, 100-92, 100-53% and 100% - 100, respectively. The lower specificities of Q-culture, enrichment-culture, and TaqMan qPCR was because of their higher sensitivities, although TaqMan qPCR also detected -specific extracellular DNA. This first evaluation of the GeneXpert MRSA/SA ETA assay with ETA samples found it to be highly sensitive, specific, user-friendly (hands-on time ~ 5 min.), and rapid (~ 66 min. assay time). Where this equipment is not available, we recommend implementing more sensitive culture-based methods for improved detection in ETA samples.