TABLE 1.

Control strains producing well-characterized β-lactamases

StrainOrganismβ-LactamaseGroupaSource or reference
CF2Enterobacter cloacaeCTX-M-1I18
Rio-4Proteus mirabilisCTX-M-2II5
VER-1E. cloacaeCTX-M-3I18
Cfr2525/96Citrobacter freundiiCTX-M-3I21
Eco3553/98E. coliCTX-M-15I1
34Salmonella enterica serovar TyphimuriumCTX-M-5II9
Rio-3Enterobacter aerogenesCTX-M-8III5
785DE. coliCTX-M-9IV36
EC97/38582E. coliCTX-M-10I31
EC984167E. coliCTX-M-14IV26
CF1E. coliCTX-M-14IV18
Rio-6E. coliCTX-M-16IV4
BM4493Klebsiella pneumoniaeCTX-M-17IV13
ILT-2K. pneumoniaeCTX-M-18IV35
ILT-3K. pneumoniaeCTX-M-19IV35
CT1bE. coliToho-1II25
S1bE. coliSHV-220
S2bE. coliSHV-78
T1bE. coliTEM-320
T4bE. coliTEM-1020
T5bE. coliTEM-5037
  • a Group I includes CTX-M-1, -3, -10 to -12, -15 (UOE-1), -22, -23, -28, -29, and -30. Group II includes CTX-M-2, -4 to -7, and -20 and Toho-1. Group III includes CTX-M-8. Group IV includes CTX-M-9, -13, -14, -16, to -19, -21, and -27 and Toho-2. Finally, group V includes CTX-M-25 and -26. We were unable to obtain a strain producing any group V enzymes.

  • b These strains are part of an unpublished isogenic panel. The original strains producing these β-lactamases were provided to the Center for Research in Anti-Infectives and Biotechnology by the referenced authors listed in the table.