A: Antibiotic Footprint is a tool to measure and understand the total magnitude of antibiotic use. Using a holistic approach, Antibiotic Footprint seeks to measure the total amount of antibiotics used in all human activities, including direct antibiotics consumption at the community and hospital levels, and indirect consumption in agricultural production.

A: The Antibiotic Footprint is necessary because many people are unaware of the problems arising from the misuse and overuse of antibiotics in humans and animals. We believe that the more people understand how much antibiotics humans and animals consume, the more likely they are to understand these problems and reduce their antibiotic use. This would have a beneficial global impact, and ultimately lead to fewer people dying from antimicrobial resistance (AMR).

A: The misuse and overuse of antibiotics is the major driver of the growing problem of antimicrobial resistance (AMR), an important cause of death worldwide. It is important to note that both appropriate use and misuse of antibiotics can increase the spread of AMR. Commonly used terms like ‘the war against superbugs’ or ‘the fight against AMR’ often lead people to request ‘stronger’ antibiotics or to focus on residual bacteria in meat, while ignoring the misuse and overuse of antibiotics. We hope that Antibiotic Footprint could be an awareness raising tool that catalyses people to reduce their Antibiotic Footprint to a minimum.

A: Antibiotic Footprint includes antibiotic use in agriculture because most of the antibiotics fed to animals are excreted un-metabolized, then enter sewage systems and water sources, thereby fostering antibiotic-resistant bacteria in the environment (AMR review, 2015). We can reduce the spread of antimicrobial resistance by reducing the antibiotic use in agriculture. Therefore, antibiotic use in agriculture is included in the Antibiotic Footprint.

A: A country’s Antibiotic Footprint is the total amount of antibiotics consumed in that country. We estimate this by combining the total amount of antibiotics consumed by humans and by animal agriculture.

We do this because most of the antibiotics fed to animals are excreted un-metabolized and then enter sewage systems and water sources, thereby fostering antibiotic-resistant bacteria in the local environment. We believe that knowing the total magnitude of antibiotic used in both human and animals in the country will have the impact to the people in the country.

While it is true that antibiotic use in animal agriculture could increase or decrease depended on the total amount of livestock, it is also true that countries that only import meat and do not raise any animals will not have antibiotics excreted from animals into the environment. Therefore, to provide the information holistically, we present antibiotic use data from all sectors per country and per human capita.

A: There is considerable similarity between the concept of ‘carbon footprint’ and that of Antibiotic Footprint. While we need to use some level of energy to survive, using too much energy has been driving climate change globally. Similarly, while we need antibiotics if we are infected with bacteria, the overuse and misuse of antibiotics have driven more and more bacteria to become ‘superbugs’ – bacteria that are resistant to multiple antibiotics. Without global action to reduce antibiotic usage, more and more people will die of these superbugs.

A: You are wrong. Antibiotics work on bacteria – hence their name. They do not work on common cold viruses. Antibiotics are not needed for most people with a common cold or an acute sore throat. Acute sore throat is self-limiting and usually triggered by a viral infection.

If you live in a developed country, please follow your doctor’s advice and do not use antibiotics to treat an acute sore throat. If you live in a developing country and can buy antibiotics over-the-counter, please note that antibiotics are not needed for acute sore throat or the common old. Please go to see a doctor if you think that your sore throat has a sign of serious illness and think that you may need antibiotics. Reducing the overuse and misuse of antibiotics for the common cold is one of the best ways to reduce your own Antibiotic Footprint.

A : Currently, indicators used for antibiotic consumption in human and animals include defined daily dosage (DDD) per 1,000 inhabitants per day and milligrams per population correction unit (PCU). Originally created to provide fair comparisons among different antibiotics and different animals, these terms are commonly used by researchers and policy makers. Details of antibiotic consumption in each country. DDD per 1,000 inhabitants per days and per mg/PCU can be found elsewhere.

We’ve chosen to communicate antibiotic consumption in simple terms like grams and tonnes of antibiotics so that anyone can easily figure out their antibiotic consumption – and calculate their antibiotic usage ‘per person’s lifetime’ or ‘per consumer product’.

A: To estimate individual antibiotic footprint “from taking antibiotics” (grams per person per year), we use the number of days from an answer to the set of questions “how many days did you take oral antibiotics in the past 12 months”. We estimate the total grams of oral antibiotics that you directly consumed in the past 12 months by multiplying “the number of days you took oral antibiotics in the past 12 months” by “the amount of grams of antibiotics that a person in your country normally would consume per day when taking a course of antibiotics”. The latter parameter was estimated from official and open-access data published by your country.

To estimate individual antibiotic footprint “from eating meat” (grams per person per year), we use the kilograms of meat that a person consumed in the past 12 months from the answers in the quiz. We estimate the total grams of antibiotics used to produce meat for your consumption in the past 12 months by multiplying “the kilograms” by “the amount of milligrams of antibiotics used per kilogram Population Correction Unit (PCU) of animal meat (i.e. mg/PCU)”. The latter parameter was obtained from official and open-access data published by your country.

The parameters used are available in the Figshare repository (https://doi.org/10.6084/m9.figshare.16944643). For countries without official and open-access data, we assume that parameters of those countries are equal to the average of those parameters from countries with official and open-access data and within similar regions and closest income levels. For South Asia, we used data from countries with similar income levels of East Asia & Pacific, because all countries in South Asia do not have official and open-access data to estimate this parameter.

A: To estimate country antibiotic footprint “from taking antibiotics” (grams per person per year), we use “the amount of tonnes of antibiotics people consume per year in a country”, which was obtained from official and open-access data published by each country. We divided this number by “the total population in the country” to estimate “the amount of grams of antibiotics each people consume per year in a country”.

To estimate individual antibiotic footprint “from eating meat” (grams per person per year), we use “milligram of antibiotics used per kilogram PCU of meat animals (i.e. mg/PCU)”, which was obtained from official and open-access data published by each country. We multiply this number with “how many kilograms of meat each person normally consumes in a year in a country”, which was obtained from Organisation for Economic Co-operation and Development (OECD) data, to estimate “the amount of grams of antibiotics used to raise animals for consumption by a person in a year in a country”.

The parameters used are available in the Figshare repository (https://doi.org/10.6084/m9.figshare.16944643). For countries without official and open-access data, we impute by assuming that parameters of those countries are equal to the average of those parameters from ‘countries with official and open-access data and within similar regions and closest income levels' (except for South Asia, we used data from countries with similar income levels of East Asia & Pacific, because all countries in South Asia have no official and open-access data to estimate this parameter).

A: This is because many countries do not publish official and open-access data of the total amount of antibiotic consumption by humans (either in tonnes or grams per person per year). Therefore, for countries without official and open-access data, we impute by assuming that parameters of those countries are equal to the average of those parameters from ‘countries with official and open-access data and within similar regions and closest income levels' (except for South Asia, we used data from countries with similar income levels of East Asia & Pacific, because all countries in South Asia have no official and open-access data to estimate these parameters). The parameters used are available in the Figshare repository (https://doi.org/10.6084/m9.figshare.16944643).