Correlation between aminoglycoside resistance profiles and DNA hybridization of clinical isolates

Abstract

DNA hybridization data and aminoglycoside resistance profiles (AGRPs) were determined for 4,088 clinical isolates from three studies (United States, Belgium, and Argentina). The correlation between susceptibility profiles and hybridization results was determined with nine DNA probes. For each of the seven aminoglycoside resistance profiles which we were able to test, the data suggested at least two distinct genes could encode enzymes which lead to identical resistance profiles. Furthermore, the DNA hybridization data showed that individual strains carried up to six unique aminoglycoside resistance genes. DNA hybridization revealed interesting differences in the frequencies of these genes by organism and by country.

Distribution and Content of Class 1 Integrons in Different Vibrio cholerae O-Serotype Strains Isolated in Thailand

“…Obtained by PCR and DNA sequencing, the findings of aadB, aadA2, blaP1, dfrA1, and dfrA15 resistance gene cassettes encoding resistances to gentamicin, kanamycin, and tobramycin; streptomycin and spectinomycin; ␤-lactams; and trimethoprim, respectively, represent the first report of the distribution of class 1 integrons among different V. cholerae O serotypes. The gene cassettes reported here corroborate previous findings of the content of class 1 integrons in Enterobactericeae and Pseudomonas spp., in which antibiotic resistance gene cassettes often encode resistances to aminoglycosides (32,39,42), ␤-lactams (40,45), and trimethoprim (2,48).…”

Aminoglycoside Resistance Genes aph(2")-Ib and aac(6′)-Im Detected Together in Strains of both Escherichia coli and Enterococcus faecium

“…The phosphocellulose paper-binding assay was performed as previously described (18). Conditions for dot blot hybridizations were performed at 42°C and have been described previously (21). DNA hybridization was performed with a collection of 4,625 aminoglycoside-resistant bacterial clinical isolates acquired by one of the coauthors (G. H. Miller) within the past decade.…”

Versatility of Aminoglycosides and Prospects for Their Future

“…The ANT(3Љ)-I enzymes show between 59% and 95% amino acid sequence identity and are widely distributed among gram-negative microorganisms. For example, ANT(3Љ)-Ia was detected in more than 90% of streptomycin-resistant clinical isolates (266 (54) is of obvious concern, because streptomycin is used for synergistic therapy of serious enterococcal infections when high-level resistance to gentamicin is encountered.…”