title: Detection and identification of methicillin resistant and sensitive strains of Staphylococcus aureus using tandem measurements.
abstract: Discrimination of methicillin resistant (MRSA) and sensitive (MSSA) strains of Staphylococcus aureus, was achieved by the specially selected lytic bacteriophage with a wide host range of S. aureus strains and a penicillin-binding protein (PBP 2a) specific antibody. A quartz crystal microbalance with dissipation monitoring (QCM-D) was employed to analyze bacteria-phage interactions. The lytic phages were transformed into phage spheroids by exposure to water-chloroform interface. Phage spheroid monolayers were transferred onto QCM-D sensors by Langmuir-Blodgett (LB) technique. Biosensors were tested in the flow mode with bacterial water suspensions, while collecting frequency and energy dissipation changes. Bacteria-spheroid interactions resulted in decreased resonance frequency and an increase in dissipation energy for both MRSA and MSSA strains. Following the bacterial binding, these sensors were further exposed to a flow of the penicillin-binding protein (PBP 2a) specific antibody conjugated latex beads. Sensors tested with MRSA responded to PBP 2a antibody beads; while sensors examined with MSSA gave no response. This experimental difference establishes an unambiguous discrimination between methicillin resistant and sensitive S. aureus strains. Both free and immobilized bacteriophages strongly inhibit bacterial growth on solid/air interfaces and in water suspensions. After lytic phages are transformed into spheroids, they retain their strong lytic activity and demonstrate high bacterial capture efficiency. The phage and phage spheroids can be used for screening and disinfection of antibiotic resistant bacteria. Other applications may include use on biosensors, bacteriophage therapy, and antimicrobial surfaces.
authors.affiliation: Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Guntupalli
authors.forename: Iryna
authors.initials: I
authors.lastname: Sorokulova
authors.forename: Eric
authors.initials: E
authors.lastname: Olsen
authors.forename: Ludmila
authors.initials: L
authors.lastname: Globa
authors.forename: Oleg
authors.initials: O
authors.lastname: Pustovyy
authors.forename: Timothy
authors.initials: T
authors.lastname: Moore
authors.forename: Bryan
authors.initials: B
authors.lastname: Chin
authors.forename: James
authors.initials: J
authors.lastname: Barbaree
authors.forename: Vitaly
authors.initials: V
authors.lastname: Vodyanoy
mesh_terms: D000907:Antibodies, Bacterial / Q000737:chemistry; D015373:Bacterial Typing Techniques; D001433:Bacteriolysis; D001435:Bacteriophages / Q000502:physiology / Q000648:ultrastructure; D058507:Host Specificity; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000187:drug effects* / Q000201:enzymology / Q000821:virology*; D046915:Penicillin-Binding Proteins / Q000276:immunology; D058525:Quartz Crystal Microbalance Techniques
chemical_list: D000907:Antibodies, Bacterial; D046915:Penicillin-Binding Proteins