When Does Overuse of Antibiotics Become a Tragedy of the Commons?

Abstract

BackgroundOver-prescribing of antibiotics is considered to result in increased morbidity and mortality from drug-resistant organisms. A resulting common wisdom is that it would be better for society if physicians would restrain their prescription of antibiotics. In this view, self-interest and societal interest are at odds, making antibiotic use a classic “tragedy of the commons”.Methods and FindingsWe developed two mathematical models of transmission of antibiotic resistance, featuring de novo development of resistance and transmission of resistant organisms. We analyzed the decision to prescribe antibiotics as a mathematical game, by analyzing individual incentives and community outcomes.ConclusionsA conflict of interest may indeed result, though not in all cases. Increased use of antibiotics by individuals benefits society under certain circumstances, despite the amplification of drug-resistant strains or organisms. In situations where increased use of antibiotics leads to less favorable outcomes for society, antibiotics may be harmful for the individual as well. For other scenarios, where a conflict between self-interest and society exists, restricting antibody use would benefit society. Thus, a case-by-case assessment of appropriate use of antibiotics may be warranted.

Antibiotic resistance as collateral damage: The tragedy of the commons in a two-disease setting

“…Let ρ P denote the recovery rate. Denoting the force of infection (only dependent on the number of individuals infected, and independent of individual choice of treatment) due to sensitive strains by λ S and due to resistant strains by λ R , a single individual follows the Markov chain $$\frac{d{X}^{false(ifalse)}}{dt}=-false({\lambda }_S+{\lambda }_{R}false)X^{false(ifalse)}+false({\rho }_P{Y}_S^{false(ifalse)}+{\rho }_P{Y}_R^{false(ifalse)}false)+{\theta }_P^{false(ifalse)}false(1-\delta false)Y_S^{false(ifalse)},$$ $$\frac{d{Y}_S^{false(ifalse)}}{dt}={\lambda }_S{X}^{false(ifalse)}-{\rho }_P{Y}_S^{false(ifalse)}-{\theta }_P^{false(ifalse)}{Y}_S^{false(ifalse)},$$ $$\frac{d{Y}_R^{false(ifalse)}}{dt}={\lambda }_R{X}^{false(ifalse)}-{\rho }_P{Y}_R^{false(ifalse)}+{\theta }_P^{false(ifalse)}\delta Y_S^{false(ifalse)},$$ which is Model 1 in the previous paper ([38]).…”

“…We recently analyzed a simple SIS model (susceptible-infective-susceptible) of drug resistance [38] for one disease, denoted by P . The state of a single individual may be completely susceptible, infected with drug-susceptible organisms only, or infected with drug-resistant organisms only.…”

“…The concept of the tragedy of the commons originated from an example on population control proposed by Lloyd [29] in 1833 and later developed by Hardin [18] in the 1960s. One example of this is seen in simple mathematical models of drug resistance, where increasing treatment of mild or early disease may benefit the individual, despite the fact that such an outcome may lead to an increase in drug-resistant bacteria and thus a decrease in the overall efficacy of antibiotic treatment [38]. …”

“…However, if increasing the population rate of treatment causes a higher population cost, a tragedy of the commons results. Previously we used this method to analyze the tragedy of the commons resulting from incentives to treat early or mild disease ([38]; see [42] for a general exposition), and in this paper we will apply the same method to a simple model of cotransmission.…”

A model-guided analysis and perspective on the evolution and epidemiology of antibiotic resistance and its future

“…Presumably motivated by concern for resistance as problem for the collective, Northern European countries tend to use narrow-spectrum antibiotics (narrow-selective antibiotics), but in many other parts of the world the rapid antibiotic effect takes the priority, justifying broad-spectrum (broadly-selective) drugs [55], yet another tragedy of the commons [56–59]. …”