title: Molecular hybridization versus isoelectric focusing to determine TEM-type beta-lactamases in gram-negative bacteria.
abstract: Isoelectric focusing and molecular hybridization with a TEM DNA probe were used to screen for TEM beta-lactamase in 328 bacterial isolates representing 11 gram-negative genera. The TEM enzyme was detected in 50% of isolates, and nine additional types of beta-lactamase could be identified in 36.9% of isolates. The TEM gene was detected in 53.6% of isolates. The results obtained by both methods were concordant in 92.7% of the entire sample. In situ colony hybridization with a specific probe therefore appears to be a convenient method to screen rapidly for the presence of homologous genetic sequences among a large number of isolates. Positive hybridization was observed for 16 isolates in which no TEM beta-lactamase was detected by isoelectric focusing. The significance of this hybridization remains to be determined.
mesh_terms: D004269:DNA, Bacterial / Q000032:analysis*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D006090:Gram-Negative Bacteria / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D007525:Isoelectric Focusing; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D001618:beta-Lactamases / Q000032:analysis* / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D001618:beta-Lactamases