Table 3.

Characteristics of CTX-M-type ESBLs

β-Lactamase Alternative name pI Country of originBacterial species Reference(s)
CTX-M-1MEN-1 8.9 Germany, Italy E. coli 12, 13
CTX-M-2 7.9 Argentina S. entericaa 11, 13
CTX-M-3 8.4 Poland C. freundii, E. coli 64
CTX-M-4 8.4 Russia S. enterica 57, 59
CTX-M-5 CTX-M-3 8.8 Latvia S. enterica 29
CTX-M-6 8.4 Greece S. enterica 58, 173
CTX-M-7 CTX-M-5 8.4 Greece S. enterica 58, 173
CTX-M-8 7.6 Brazil P. mirabilis, E. cloacae, E. aerogenes, C. amalonaticus 21
CTX-M-9 8.0 Spain E. coli 148
CTX-M-10 8.1 Spain E. coli Oliver et al.b
Toho-1 7.8Japan E. coli 72
Toho-2 7.7 Japan E. coli 88
  • a All strains of S. entericawere serovar Typhimurium.

  • b A. Oliver, J. C. Pérez-Dı́az, T. M. Coque, F. Baquero, and R. Cantón, 40th Intersci. Conf. Antimicrob. Agents Chemother., abstr. 1480, 2000.