Antibiotic resistance kills about 25,000 people every year in Europe. Many bacteria cause serious infections in humans like Salmonella, which have developed resistance to other common antibiotics. Ampicillin was the first broad-spectrum antibiotic used for treatments of infections caused by enterobacteria. This was first released in the United Kingdom in 1961. Soon after, between 1962-1964, the first outbreak of this disease in humans was caused by ampicillin-resistance strains of Salmonella enterica serotype Typhimurium. The study aimed to date the first occurrence and spread of the resistant strain.