Detection of Staphylococcus aureus via IgY-based immunomagnetic separation and a phage lysin LysGH15-based colloidal gold immunochromatographic assay.

INTRODUCTION: Staphylococcus aureus (S. aureus) is an important human pathogen that frequently causes disease in hospital and community settings. Due to the pervasive emergence of virulent and multidrug-resistant methicillin-resistant S. aureus (MRSA) strains, S. aureus infections have become a leading cause of morbidity and mortality. OBJECTIVES: We aimed to develop a reliable and effective detection method that can be used for preventing and managing infections caused by S. aureus. METHODS: A novel S. aureus detection platform that combines immunomagnetic separation via immunomagnetic beads (IMBs) and the phage lysin LysGH15-based colloidal gold immunochromatographic assay (GICA) (named IMBs-GICA) was developed. IMBs-GICA was performed on 426 consecutive samples, including 185, 107, 74 and 60 samples from sputum, urine, bronchoalveolar lavage fluid (BALF) and serum samples, respectively. S. aureus culture and PCR assays were routinely conducted in parallel. RESULTS: By targetingS. aureus, the IMBs-GICA platform could detect as little as 40 CFU/mL within 35 min. Among the clinical specimens, 38 samples were S. aureus culture positive, and 36 were IMBs-GICA positive, resulting in an IMBs-GICA sensitivity of 89.5 % (95 % confidence interval 74.3-96.6) and a specificity of 99.5 % (97.9-99.9). DISCUSSION: IMBs-GICA can rapidly and sensitively detect for S. aureus, demonstrating the potential utility of this developed method in the field of testing.