Sequence analysis and biochemical characterisation of chromosomal CAV-1 (Aeromonas caviae), the parental cephalosporinase of plasmid-mediated AmpC 'FOX' cluster.
Aeromonas caviae CIP 74.32 was resistant to amoxicillin, ticarcillin and cephalothin, and susceptible to cefoxitin, cefotaxime, ceftazidime, aztreonam and imipenem. This strain produced a cephalosporinase (pI 7.2) and an oxacillinase (pI 8.5). The cephalosporinase gene cav-1 was cloned and sequenced. Unlike A. caviae donor, Escherichia coli pNCE50 transformant producing CAV-1 beta-lactamase was resistant to cefoxitin. The deduced protein sequence CAV-1 contained 382 amino acids, and shared >96% homology with FOX-1 to FOX-5 cephalosporinase. CAV-1 presented only two amino acid substitutions (Thr270Ser and Arg271Ala) with FOX-1. CAV-1 is the chromosomal putative ancestor of the FOX family, a cluster of class C/group 1 plasmidic cephalosporinases spreading in Klebsiella and E. coli clinical isolates via conjugative plasmids.
Fosse
Thierry
T
Laboratoire de Bactériologie, Hôpital L'Archet 2, Centre Hospitalier Universitaire, B P 3079, 06202 Nice, Cedex 3, France. fosse@unice.fr
Giraud-Morin
Chantal
C
Madinier
Isabelle
I
Labia
Roger
R
D000333:Aeromonas / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins; D002440:Cefoxitin / Q000494:pharmacology; D002510:Cephalosporinase / Q000737:chemistry* / Q000235:genetics*; D002876:Chromosomes, Bacterial; D008969:Molecular Sequence Data; D010957:Plasmids; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000737:chemistry / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002440:Cefoxitin; D002510:Cephalosporinase; C444464:beta-lactamase FOX-5; C048795:AmpC beta-lactamases; D001618:beta-Lactamases