Tetracycline and streptomycin resistance genes, transposons, and plasmids in Salmonella enterica isolates from animals in Italy.
Fifty-eight multidrug-resistant Salmonella enterica strains of 20 serotypes, isolated from animal sources in Italy, were analyzed for tet(A) and strA-strB, conferring tetracycline and streptomycin resistance, respectively. The strA and strB genes were highly prevalent in Salmonella strains of our collection, being detected in 84% of the streptomycin-resistant strains. In many strains, the strA and strB genes were linked to a particular Tn5393-derivative transposon characterized by the presence of the insertion sequence IS1133, previously identified only in the plant pathogen Erwinia amylovora. Sixty-eight percent of the tetracycline-resistant strains were tet(A) positive, indicating that this gene is widely diffused in Salmonella strains circulating in animals in Italy. Most of the tet(A) genes were localized within a deleted Tn1721 transposon variant. Two prevalent repN and repI1 resistance plasmids were identified in Salmonella isolates of our collection.
Pezzella
Cristina
C
Laboratory of Bacteriology and Medical Mycology, Istituto Superiore di Sanità, Rome, Italy.
Ricci
Antonia
A
DiGiannatale
Elisabetta
E
Luzzi
Ida
I
Carattoli
Alessandra
A
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003227:Conjugation, Genetic; D017931:DNA Primers; D004251:DNA Transposable Elements / Q000235:genetics*; D005798:Genes, Bacterial; D032023:Integrons / Q000235:genetics; D007558:Italy; D010957:Plasmids / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012480:Salmonella Infections / Q000382:microbiology; D019779:Salmonella enterica / Q000187:drug effects / Q000235:genetics*; D013307:Streptomycin / Q000494:pharmacology*; D013752:Tetracycline / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D017931:DNA Primers; D004251:DNA Transposable Elements; D013752:Tetracycline; D013307:Streptomycin