Abstract
An immunochemical strategy to detect and quantify AIP-IV, the quorum sensing (QS) signaling molecule produced by Staphylococcus aureusagr type IV, is reported here for the first time. Theoretical calculations and molecular modeling studies have assisted on the design and synthesis of a suitable peptide hapten (AIPIVS), allowing to obtain high avidity and specific antibodies toward this peptide despite its low molecular weight. The ELISA developed achieves an IC50 value of 2.80 ± 0.17 and an LOD of 0.19 ± 0.06 nM in complex media such as 1/2 Tryptic Soy Broth. Recognition of other S. aureus AIPs (I–III) is negligible (cross-reactivity below 0.001%), regardless of the structural similarities. A pilot study with a set of clinical isolates from patients with airways infection or colonization demonstrates the potential of this ELISA to perform biomedical investigations related to the role of QS in pathogenesis and the association between dysfunctional agr or the agr type with unfavorable clinical outcomes. The AIP-IV levels could be quantified in the low nanomolar range in less than 1 h after inoculating agr IV-genotyped isolates in the culture broth, while those genotyped as I–III did not show any immunoreactivity after a 48 h growth, pointing to the possibility to use this technology for phenotyping S. aureus. The research strategy here reported can be extended to the rest of the AIP types of S. aureus, allowing the development of powerful multiplexed chips or point-of-care (PoC) diagnostic devices to unequivocally identify its presence and its agr type on samples from infected patients.
Highlights
An immunochemical strategy to detect and quantify AIP-IV, the quorum sensing (QS) signaling molecule produced by Staphylococcus aureus agr type IV, is reported here for the first time
Methicillin-resistant S. aureus (MRSA) is estimated to account for 25% of the S. aureus strains with a prevalence of up to 50% in some areas, generating a social and economic burden by means of both community-acquired infections (CAIs) and healthcare-associated infections (HAIs).[6−8] S. aureus is one of the earliest pathogens isolated from the airways of cystic fibrosis patients, being positive for more than 70% of neonates and 45% of those becoming persistently colonized.[9]
Interesting studies are already addressing the clinical significance and the role of QS molecules from Gram-negative bacteria such as P. aeruginosa; for their QS signaling molecules, we have reported the development of specific antibodies.[72−74] Similar studies could be addressed in the near future, which may provide interesting information in respect to the involvement of these QS molecules on pathogenesis, as well as the possibility to develop powerful technologies for the diagnostic and surveillance of S. aureus infections
Summary
An immunochemical strategy to detect and quantify AIP-IV, the quorum sensing (QS) signaling molecule produced by Staphylococcus aureus agr type IV, is reported here for the first time. Quantitative real-time PCR, focused on the identification of particular genome sequences, and matrix-assisted laser desorption ionization-time-of-flightmass spectrometry (MALDI-TOF-MS), based on the analysis of the mass distribution of bacterial proteins, are able to more rapidly unequivocally identify S. aureus[16−18] and other pathogens These approaches often still require prior culture enrichment steps, expensive equipment, highly trained personnel, and extensive validation for clinical interpretation of the results on routine clinical analyses, which make their wide implementation difficult in all clinical settings or near the patient primary attention centers.[16−18] An additional unmet challenge of the diagnosis of infectious diseases is the difficulty to differentiate simple carriers from infected patients.[19] Diagnostic approaches that fulfill the ASSURED (affordability, sensitivity, specificity, user-friendliness, rapidity and robustness, no equipment needed, and deliverable to end users)[20] criteria are a recognized unmet need for many diseases and to diagnose infections. Agr typing could be of great interest to manage infections and distinguish between colonization and infection.[40−44]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
