A novel sequence framework (bla_TEM-1G) encoding the parental TEM-1 beta-lactamase

Abstract

A novel parental bla TEM gene (bla TEMÀ1G ), encoding a TEM-1 L-lactamase (pI of 5.4) produced by the uropathogenic Escherichia coli strain FMV194 was isolated from a dog. We report PCR^restriction fragment length polymorphism analysis and nucleotide sequencing of this gene. The bla TEMÀ1G sequence was identical to the bla TEMÀ1C gene framework in the coding and promoter (P3) regions, except for a silent G 604 CT mutation in the coding region. Molecular phylogenetic analysis of parental bla TEM genes indicated two distinct groups, one comprising bla TEMÀ1F and bla TEMÀ2 . The other group comprises bla TEMÀ1C which is the probable ancestor of bla TEMÀ1A , bla TEMÀ1D and bla TEMÀ1G . The bla TEMÀ1G gene has the same framework as a gene encoding an inhibitor-resistant TEM L-lactamase produced by an E. coli strain of human origin. Thus, parental bla TEM genes encoding L-lactamases in E. coli strains isolated from different host species, in this case human and canine, may be phylogenetically very close. ß

Extended-Spectrum β-Lactamases in Klebsiella pneumoniae Bloodstream Isolates from Seven Countries: Dominance and Widespread Prevalence of SHV- and CTX-M-Type β-Lactamases

“…This was found in 3 SHV-2-type ␤-lactamase amplicons. Like the situation that exists in TEM (TEM-1A to -G), there is molecular heterogeneity of bla SHV (23,35). It is perplexing to us that in seven of the isolates, our SHV PCR screening primers did not detect bla SHV (isolates 8, 9, 10, 11, 465, 466, and 467 [see summary in Table 4]).…”

Molecular Characterization of Resistance to Extended-Spectrum Cephalosporins in Clinical Escherichia coli Isolates from Companion Animals in the United States

“…1); the bla TEM-1 gene was the most prominent (82.5%). The bla TEM-1 variant was previously identified in clinical E. coli isolates from companion animals in Europe but not in the United States (16,18,40). Although the TEM-1 variant is not considered an ESBL, its clinical importance relies on its potential to undergo mutations to increase its activity against other ␤-lactams (10,25).…”

Genetic Detection of Extended-Spectrum β-Lactamase-Containing Escherichia coli Isolates from Birds of Prey from Serra da Estrela Natural Reserve in Portugal

“…The bla TEM-1d genetic variant is relatively infrequent, although it has been detected in some other studies (19). Two ESBL-containing E. coli isolates were positive for the presence of bla , and another three isolates carried the bla SHV-5 gene.…”