Resistance Surveillance and Monitoring Systems

Surveillance turns scattered laboratory results into a coherent picture of where, how often, and in which organisms resistance occurs. Systematic collection of antimicrobial susceptibility data, harmonized by standard testing and interpretive criteria, lets clinicians, hospitals, and countries track resistance over time, detect emerging threats, and guide policy. This topic examines how resistance is measured and monitored.

Definition

Resistance surveillance and monitoring is the systematic, ongoing collection, analysis, and interpretation of antimicrobial susceptibility data across laboratories, institutions, and populations, used to describe the distribution and trends of resistance and to inform clinical and public-health action.

Scope

The topic covers antimicrobial susceptibility testing and its interpretive breakpoints, the construction of antibiograms, the structure of local, national, and global surveillance networks, and the use of surveillance data to define priority pathogens and inform action. It describes measurement and monitoring systems and is not a laboratory protocol or a treatment guide.

Core questions

• How is the resistance of an organism measured and interpreted?
• How are individual laboratory results aggregated into antibiograms and surveillance reports?
• How do local, national, and global surveillance systems fit together?
• How does surveillance inform priority-setting and policy?

Key concepts

• Antimicrobial susceptibility testing
• Minimum inhibitory concentration (MIC) and breakpoints
• Interpretive standards (EUCAST, CLSI)
• Antibiogram
• Sentinel and laboratory-based surveillance
• Global surveillance networks (e.g., GLASS)
• Priority-pathogen lists

Mechanisms

Surveillance begins with laboratory testing that classifies an organism as susceptible or resistant to an agent, typically by measuring the minimum inhibitory concentration and applying interpretive breakpoints set by standards bodies such as EUCAST and CLSI; harmonized breakpoints make results comparable across laboratories. Aggregating results yields the antibiogram, a summary of resistance frequencies for an institution or region. Linking laboratories into sentinel and national networks, and connecting those to global systems, produces population-level estimates of resistance prevalence and trends. These data feed priority-setting exercises that identify the pathogens of greatest concern and direct research and policy.

Clinical relevance

Surveillance data, expressed locally as the antibiogram, describe the resistance landscape that informs empirical-therapy policy and infection-prevention priorities at the institutional and population level. This topic explains how resistance is measured and tracked rather than prescribing therapy for any individual patient.

Epidemiology

Surveillance coverage is uneven globally, with the most robust data from high-income settings and important gaps elsewhere, which complicates worldwide burden estimation. International efforts have sought to standardize and expand monitoring, and surveillance evidence underpins the priority-pathogen lists used to focus the response to resistance.

History

Resistance monitoring grew from local hospital antibiograms toward coordinated national and, later, international networks. The standardization of susceptibility testing and breakpoints made data comparable across sites, and the establishment of global surveillance frameworks and priority-pathogen lists marked the maturation of monitoring as an instrument of policy.

Debates

How should susceptibility breakpoints be set and harmonized?

Interpretive breakpoints determine whether an isolate is reported as resistant, and differences in how standards bodies set and revise them affect comparability of surveillance data across regions and over time.

Seminal works

• tacconelli-2018
• laxminarayan-2013

Frequently asked questions

What is an antibiogram?

An antibiogram is a summary of the proportion of tested isolates of a given organism that are susceptible or resistant to a panel of antimicrobials, usually compiled for a hospital or region to describe the local resistance landscape.

Why do breakpoints matter for surveillance?

Breakpoints are the interpretive thresholds that classify an organism as susceptible or resistant; because they determine what counts as resistance, differences or changes in breakpoints affect how surveillance results compare across laboratories and over time.