18,19 Not only is the method labor-intensive and time-consuming (∼2 days to several weeks) but also shows high incidence of false-positive results due to contamination. The current gold standard for diagnosing bacterial infections in the clinic is microbial culture. 14–17 However, a rapid and simple diagnostic test that can be easily applied in the clinic has been lacking. 9–13 The rapid discrimination of Gram-positive and Gram-negative pathogens can greatly reduce the overuse of antibiotics, allowing proper treatment and improvement in patient survival, preventing further transmission, and reducing the spread of antimicrobial resistance. 9,10 This has led to serious problems such as resulting in poor therapeutic efficacy and survival of the patient, subsequent spread of infection to the community, and the emergence of superbugs with multidrug resistance. 5–8 Generally, the antibiotics have been prescribed in large dosages, separately or in combinations, which target a broad spectrum of Gram-positive and Gram-negative pathogens, without performing any experimental assay for classification of the pathogen prior to treatment. 3,4 For decades, antibiotics such as aminoglycosides, carbapenems, cephalosporins, and glycopeptides, have been used, which act on a broad spectrum of microbes by targeting bacterial functions or growth processes, including the binding and inhibition of cell wall components, modifying cell membrane structure, or interfering with essential bacterial enzymes involved with DNA replication or protein synthesis. 1,2 Among the various pathogens causing the infections, Gram-positive and Gram-negative bacteria show substantial differences in molecular structure and biological function, allowing them to be differentially targeted for treatment. Introduction Infectious diseases caused by bacterial pathogens have been threatening communities worldwide, showing high incidence of morbidity as well as mortality. We anticipate that the nanobead aggregation assay can be potentially applied as a rapid and simple sensing platform, which can be easily miniaturized and enable point-of-care diagnosis of Gram-positive infections. We also utilized a porous filter system for the assay, which allowed discrimination of Gram-positive targets with higher selectivity, and demonstrated feasibility as a simple diagnostic assay with minimal technical components. Without any pre-processing steps, the addition of various types of Gram-positive pathogens to the nanobeads resulted in the formation of blue precipitates, which could be observed with the naked eye in ∼30 min. Vancomycin was immobilized onto blue-colored polymeric nanobeads to induce specific and multivalent binding with the Gram-positive bacterial cell wall and subsequent agglomeration. Herein, we describe a rapid, one-step colorimetric assay based on the formation of nano-aggregates using nanobeads targeting Gram-positive bacteria. Development of a rapid, point-of-care assay for diagnosing bacterial infections is crucial for subsequent treatment of the patient and preventing the overuse of antibiotics.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |