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Gene Review

ampC  -  beta-lactamase

Escherichia coli UTI89

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Disease relevance of ampC

  • Genetic and functional characterization of the cephalosporinases produced by 65 clonally unrelated clinical Escherichia coli isolates revealed genetic diversity of the ampC genes and showed that Gln287, Cys287, Pro296, Leu298, and Phe350 substitutions were involved in extension of the hydrolysis spectrum to include ceftazidime and cefepime [1].
  • The chromosomal ampC beta-lactamase in Citrobacter freundii and Enterobacter cloacae is inducible by beta-lactam antibiotics [2].
  • Inducible expression of the chromosomal cdiA from Citrobacter diversus NF85, encoding an ambler class A beta-lactamase, is under similar genetic control to the chromosomal ampC, encoding an ambler class C enzyme, from Citrobacter freundii OS60 [3].

High impact information on ampC

  • Addition of the muropeptide, anhMurNAc-tripeptide, which accumulates in beta-lactamase-overproducing mutants, counteracts the negative effect of UDP-MurNAc-pentapeptide, restoring the innate ability of AmpR to induce ampC expression in vitro [4].
  • The murein precursor, UDP-MurNAc-pentapeptide, decreases AmpR-mediated transcriptional activation in vitro, but has no effect on an AmpR(G102E) mutant that mediates constitutive activation of ampC in vivo [4].
  • When an inducible ampC gene is introduced on a plasmid into Escherichia coli together with its transcriptional regulator ampR, the plasmid-borne beta-lactamase is still inducible [2].
  • The low-level cephalosporin resistance of the remaining isolates (n = 85; 49%) was inferred to result from reduced permeability or, in E. coli, from hyperexpression of chromosomal ampC [5].
  • Furthermore, pulse-chase experiments using this mutant revealed that the 17% of the beta-lactamase precursor accumulated in the cell after a 4-min chase in the absence of IPTG, although almost all of the precursors were converted into the mature from after a 1-min chase in the presence of IPTG [6].

Chemical compound and disease context of ampC


Biological context of ampC


Anatomical context of ampC


  1. Naturally occurring extended-spectrum cephalosporinases in Escherichia coli. Mammeri, H., Poirel, L., Fortineau, N., Nordmann, P. Antimicrob. Agents Chemother. (2006) [Pubmed]
  2. AmpG, a signal transducer in chromosomal beta-lactamase induction. Lindquist, S., Weston-Hafer, K., Schmidt, H., Pul, C., Korfmann, G., Erickson, J., Sanders, C., Martin, H.H., Normark, S. Mol. Microbiol. (1993) [Pubmed]
  3. Inducible expression of the chromosomal cdiA from Citrobacter diversus NF85, encoding an ambler class A beta-lactamase, is under similar genetic control to the chromosomal ampC, encoding an ambler class C enzyme, from Citrobacter freundii OS60. Jones, M.E., Bennett, P.M. Microb. Drug Resist. (1995) [Pubmed]
  4. Cytosolic intermediates for cell wall biosynthesis and degradation control inducible beta-lactam resistance in gram-negative bacteria. Jacobs, C., Frère, J.M., Normark, S. Cell (1997) [Pubmed]
  5. Wide geographic spread of diverse acquired AmpC {beta}-lactamases among Escherichia coli and Klebsiella spp. in the UK and Ireland. Woodford, N., Reddy, S., Fagan, E.J., Hill, R.L., Hopkins, K.L., Kaufmann, M.E., Kistler, J., Palepou, M.F., Pike, R., Ward, M.E., Cheesbrough, J., Livermore, D.M. J. Antimicrob. Chemother. (2007) [Pubmed]
  6. The effect of Srb, a homologue of the mammalian SRP receptor alpha-subunit, on Bacillus subtilis growth and protein translocation. Oguro, A., Kakeshita, H., Takamatsu, H., Nakamura, K., Yamane, K. Gene (1996) [Pubmed]
  7. Characterization of antimicrobial resistance patterns and class 1 integrons in Escherichia coli O26 isolated from humans and animals. Srinivasan, V., Gillespie, B.E., Nguyen, L.T., Headrick, S.I., Murinda, S.E., Oliver, S.P. Int. J. Antimicrob. Agents (2007) [Pubmed]
  8. GcvA, a LysR-type transcriptional regulator protein, activates expression of the cloned Citrobacter freundii ampC beta-lactamase gene in Escherichia coli: cross-talk between DNA-binding proteins. Everett, M., Walsh, T., Guay, G., Bennett, P. Microbiology (Reading, Engl.) (1995) [Pubmed]
  9. Characterisation of CTX-M and AmpC genes in human isolates of Escherichia coli identified between 1995 and 2003 in England and Wales. Hopkins, K.L., Batchelor, M.J., Liebana, E., Deheer-Graham, A.P., Threlfall, E.J. Int. J. Antimicrob. Agents (2006) [Pubmed]
  10. Overexpression of bacterial hemoglobin causes incorporation of pre-beta-lactamase into cytoplasmic inclusion bodies. Rinas, U., Bailey, J.E. Appl. Environ. Microbiol. (1993) [Pubmed]
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