title: Economic implications of the dynamic relationship between antibiotic use and hospital-acquired infections.
abstract: OBJECTIVE
  The emergence and spread of antimicrobial resistance is still an unresolved problem worldwide. Recent evidence shows correlations between the volume of broad-spectrum antibiotics used in the hospital setting and the incidence of multidrug-resistant bacteria. According to this dynamic relationship, loss of antibiotic activity can be modeled as a negative externality of antibiotic consumption.
  
  
  METHODS
  The present study proposes to present an economic model describing the probability of antibiotic treatment failure as a function of antimicrobial use and alcohol-based hand-rub use. Furthermore, the results of recently conducted time-series analyses and cost-of-illness studies are applied to the model to determine the externalities of antibiotic consumption and alcohol-based hand-rub use with respect to the costs of hospital-acquired infections.
  
  
  RESULTS
  According to our calculations, the consumption of third-generation cephalosporins and fluoroquinolones is associated with the highest negative externalities (€143 and €101, respectively) because their use has been shown to be associated with most types of hospital-acquired infections. In contrast, the use of alcohol-based hand-rub solution for hand disinfection is associated with a positive externality of 41 cents per single disinfection of the hands.
  
  
  CONCLUSIONS
  The externalities presented in this work represent a possible application of cost-of-illness data to quantify the impact of antibiotic use on antimicrobial resistance. In addition, the results indicate that most economic research on the topic is biased in assuming the overall use of antibiotics to be responsible for the spread of antimicrobial resistance.
authors.affiliation: Department of Environmental Health Sciences, University Medical Center Freiburg, Freiburg, Germany. klaus.kaier@vwl.uni-freiburg.de.
authors.forename: Klaus
authors.initials: K
authors.lastname: Kaier
mesh_terms: D000900:Anti-Bacterial Agents / Q000145:classification / Q000191:economics* / Q000494:pharmacology*; D003015:Clostridium Infections / Q000453:epidemiology; D003428:Cross Infection / Q000191:economics* / Q000453:epidemiology*; D024881:Drug Resistance, Bacterial / Q000187:drug effects*; D004363:Drug Utilization; D006235:Hand Disinfection / Q000379:methods; D006742:Hospital Bed Capacity; D006801:Humans; D015994:Incidence; D007902:Length of Stay; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification; D018803:Models, Economic; D013203:Staphylococcal Infections / Q000453:epidemiology; D013997:Time Factors; D001618:beta-Lactamases / Q000096:biosynthesis
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases