title: A computational model of antibiotic-resistance mechanisms in methicillin-resistant Staphylococcus aureus (MRSA).
abstract: An agent-based model of bacteria-antibiotic interactions has been developed that incorporates the antibiotic-resistance mechanisms of Methicillin-Resistant Staphylococcus aureus (MRSA). The model, called the Micro-Gen Bacterial Simulator, uses information about the cell biology of bacteria to produce global information about population growth in different environmental conditions. It facilitates a detailed systems-level investigation of the dynamics involved in bacteria-antibiotic interactions and a means to relate this information to traditional high-level properties such as the Minimum Inhibitory Concentration (MIC) of an antibiotic. The two main resistance strategies against beta-lactam antibiotics employed by MRSA were incorporated into the model: beta-lactamase enzymes, which hydrolytically cleave antibiotic molecules, and penicillin-binding proteins (PBP2a) with reduced binding affinities for antibiotics. Initial tests with three common antibiotics (penicillin, ampicillin and cephalothin) indicate that the model can be used to generate quantitatively accurate predictions of MICs for antibiotics against different strains of MRSA from basic cellular and biochemical information. Furthermore, by varying key parameters in the model, the relative impact of different kinetic parameters associated with the two resistance mechanisms to beta-lactam antibiotics on cell survival in the presence of antibiotics was investigated.
authors.affiliation: Modelling and Scientific Computing Group, School of Computing, Faculty of Engineering and Computing, Dublin City University, Glasnevin, Dublin 9, Ireland. jamurphy@computing.dcu.ie
authors.forename: James T
authors.initials: JT
authors.lastname: Murphy
authors.forename: Ray
authors.initials: R
authors.lastname: Walshe
authors.forename: Marc
authors.initials: M
authors.lastname: Devocelle
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D003198:Computer Simulation; D008712:Methicillin / Q000627:therapeutic use; D016106:Methicillin Resistance; D008954:Models, Biological; D046915:Penicillin-Binding Proteins / Q000378:metabolism; D013203:Staphylococcal Infections / Q000188:drug therapy; D013211:Staphylococcus aureus / Q000187:drug effects / Q000378:metabolism*; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D046915:Penicillin-Binding Proteins; D001618:beta-Lactamases; D008712:Methicillin