In 1965, the transferability of ampicillin resistance was reported, and the plasmid-encoded mechanism of resistance for 2 Salmonella sp. isolates from the United Kingdom and 1 Escherichia coli isolate from Greece was determined. Resistance (R) factors from Salmonella sp. isolates were designated R1818 and R7268 (R7268 encoding the current TEM-1). The E. coli isolate and its plasmid were named TEM (encoding the current TEM-2) because the isolate was recovered from a feces culture of an Athenian patient named Temoniera in 1963.
β-lactam resistance is a problem worldwide; >2,000 β-lactamases are currently identified. Of these β-lactamases, >200 enzymes are classified within TEM family, including extended-spectrum β-lactamases (ESBLs). However, the original TEM-1 and TEM-2hydrolyze only penicillin derivatives.
Sources & copyright: https://wwwnc.cdc.gov/eid/article/24/4/pdfs/et-2404.pdf