Combined ramR mutation and presence of a Tn1721-associated tet(A) variant in a clinical isolate of Salmonella enterica serovar Hadar resistant to tigecycline.
A Salmonella enterica serovar Hadar strain resistant to tigecycline (MIC, 16 microg/ml) was isolated. Molecular characterization revealed the presence of a plasmid-borne tet(A) variant associated with Tn1721 mediating a rise of the MIC for tigecycline when transferred to Escherichia coli. Additionally, a truncating mutation in ramR was detected. Transformation with wild-type ramR but not with the mutated ramR lowered the MIC for tigecycline. Characterization of this Salmonella isolate implicates ramR in resistance to tigecycline.
Hentschke
M
M
Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. m.hentschke@uke.de
Christner
M
M
Sobottka
I
I
Aepfelbacher
M
M
Rohde
H
H
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017920:Antiporters / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D004251:DNA Transposable Elements; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D014644:Genetic Variation; D006801:Humans; D008911:Minocycline / Q000031:analogs & derivatives* / Q000494:pharmacology; D009154:Mutation; D012097:Repressor Proteins / Q000235:genetics*; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D000078304:Tigecycline
D000900:Anti-Bacterial Agents; D017920:Antiporters; D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D012097:Repressor Proteins; C079051:tetA protein, Bacteria; D000078304:Tigecycline; D008911:Minocycline