Contribution of the Rv2333c efflux pump (the Stp protein) from Mycobacterium tuberculosis to intrinsic antibiotic resistance in Mycobacterium bovis BCG.
OBJECTIVE
To characterize the efflux pump encoded by the gene Rv2333c from Mycobacterium tuberculosis, and assess its contribution to intrinsic antibiotic resistance using Mycobacterium bovis BCG as a model organism.


METHODS
Firstly, the Rv2333c gene was expressed from a multicopy plasmid in M. bovis BCG. Secondly, the gene was inactivated in the chromosome of M. bovis BCG. Antibiotic susceptibility tests and tetracycline uptake/efflux experiments were carried out with the strains mentioned above.


RESULTS
When the Rv2333c gene was inactivated in the M. bovis BCG chromosome, there was a decrease in the MIC values of spectinomycin and tetracycline, and an increase in [3H]tetracycline accumulation. When the Rv2333c gene was cloned into a multicopy plasmid, there was an increase in the MIC values of spectinomycin and tetracycline, and a decrease in [3H]tetracycline accumulation. These results indicate that both antibiotics are substrates of the Rv2333c efflux pump, which has been named Stp, for Spectinomycin Tetracycline efflux Pump.


CONCLUSIONS
The Rv2333c efflux pump (Stp protein) of M. tuberculosis contributes to intrinsic spectinomycin and tetracycline resistance.
Ramón-García
Santiago
S
Departamento de Microbiología, Medicina Preventiva y Salud Pública, Universidad de Zaragoza, 50009 Zaragoza, Spain.
Martín
Carlos
C
De Rossi
Edda
E
Aínsa
José A
JA
D024881:Drug Resistance, Bacterial; D005798:Genes, Bacterial / Q000502:physiology*; D008826:Microbial Sensitivity Tests; D009163:Mycobacterium bovis / Q000187:drug effects* / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D000198:Spectinomycin / Q000493:pharmacokinetics; D013752:Tetracycline / Q000493:pharmacokinetics
D000198:Spectinomycin; D013752:Tetracycline