[Evaluation of a rapid assay for detection of PBP2a Staphylococcus aureus]. / Evaluación de una prueba rápida para la detección de PBP2a en Staphylococcus aureus.

OBJECTIVE: Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen causing both healthcare-associated and community-acquired infection. Rapid and accurate detection of this pathogen is crucial for the use of appropriate antimicrobial therapy and the control of nosocomial spread. METHODS: A total of 107 S. aureus strains were assayed for methicillin resistance: Vitek2® (bioMérieux), CHROMagarTM MRSA II (BD Becton Dickinson), disk diffusion in agar for cefoxitin 30 µg and immunochromatography PBP2a SA Culture Colony Test (AlereTM). The results of conventional tests were compared with the "gold standard" PCR test for mecA gene. RESULTS: Sensitivity and specificity were: disk diffusion for cefoxitin 100% and 100% respectively, Vitek2® 100 and 100%, CHROMagarTM MRSA II 100 and 96%, and ICPBP2a detection 98,25% and 100%. CONCLUSIONS: ICPBP2a Culture Colony Test (AlereTM) is fast, efficient and economical technique for detection of penicillin binding protein 2a (PBP2a) from isolates. This assay is a useful tool for the management of hospital outbreaks.

[Evaluation of an immunochromatographic test for the detection of OXA-48 carbapenemase]. / Evaluación de un ensayo inmunocromatográfico para la detección de carbapenemasa OXA-48.

OBJECTIVE: Detection and differentiation of various types of carbapenemases is crucial to their control and dissemination. OXA-48 is the most common carbapenemase in Spain and in our environment. The aim of this study is the evaluation of a new immunochromatographic test OXA-48 Card letitest (Coris, BioConcept Belgium) to detect this carbapenemase from solid media. METHODS: During the last year 151 strains of carbapenemase producing bacteria have been isolated, of which 136 were OXA-48 (126 Klebsiella pneumoniae, 1 Klebsiella oxytoca, 5 Escherichia coli, 4 Enterobacter cloacae), and 15 producing other carbapenemases . These 15 strains with other 73 carrying other resistance mechanisms (54 extended-spectrum ß-lactamases producers and 19 with other mechanisms) were used as negative controls. RESULTS: One hundred and thirty six strains carrying OXA-48 were positive with the test OXA-48 Card letitest and the 88 species used as controls were negative, resulting in a sensitivity and specificity of 100%. CONCLUSIONS: The OXA-48 Card letitest is simple, quick, safe and cheap (approx. 6€/test) and can be used in microbiology laboratories to confirm the production of OXA-48 carbapenemase in clinical isolates.