Cloning and sequence analysis of a plasmid-encoded chloramphenicol acetyltransferase gene from Staphylococcus intermedius

Abstract

The chloramphenicol acetyltransferase gene (cat) of a 3.9 kb chloramphenicol resistance (CmR) plasmid from Staphylococcus intermedius, designated pSCSl, was cloned into an Escherichia coli plasmid vector. Sequence analysis revealed a high degree of base similarity with the cat gene of the S. aureus CmR plasmid pC221 but there were several differences in the regulatory region. A lesser degree of similarity was observed between the cat gene of the S. intermedius plasmid and the cat gene of the S. aureus plasmid pC194.

Nucleotide sequence and phylogeny of a chloramphenicol acetyltransferase encoded by the plasmid pSCS7 from Staphylococcus aureus

“…The pSCS7-encoded CAT monomer was slightly smaller than the previously determined CAT monomers in staphylococci, which ranged between 215 and 219 amino acids (2,3,13,22,25,28). Comparisons revealed that the cat gene of pSCS7 exhibited 90% nucleotide sequence homology and 85% amino acid identity to the cat gene of pSCS5.…”

“…The enzyme responsible for the acetylation was often found to be encoded by extrachromosomal, mobile DNA elements (17,29). In staphylococci, Cmr is the only known resistance marker, which is, to the best of our knowledge, exclusively located on plasmids (17,(25)(26)(27)(28). In gram-negative bacteria, the determinants for Cmr have also been found to be associated with plasmids or transposons (1,18,19,29).…”

“…The determinants for Cmr in staphylococci have been found to be exclusively located on small plasmids up to 5.2 kb in size (17,(25)(26)(27)(28). These plasmids have been classified on the basis of restriction endonuclease analyses and DNA-DNA hybridizations to belong to three families (10).…”

“…All of these staphylococcal Cmr plasmids encode an inducible chloramphenicol acetyltransferase (CAT). So far, molecular analyses have been performed on the cat genes of the plasmids pC221 (2,22), pUB112 from S. aureus (3), pSCS1 from Staphylococcus intermedius (28), pC194 from S. aureus (13), and the recently described pSCS5 from Staphylococcus haemolyticus (25).…”

“…Escherichia coli TG1 [supE hsd A5 thi A(lac-proAB) F'(traD36 proAB+ lacdq lacZ AM15); Stratagene] was used as the recipient for plasmid pBluescript II SK+ and its recombinant derivatives. Growth conditions were as described previously (25,28). The production of singlestranded DNA with the helper phage M13K07 (Stratagene) was performed by the recommendations of Vieira and Messing (35).…”