Fluoroquinolone Efflux in Streptococcus suis Is Mediated by SatAB and Not by SmrA

• Published in: Antimicrobial Agents and Chemotherapy Vol. 55; no. 12; pp. 5850 - 5860
• Main Authors: Escudero, Jose Antonio, San Millan, Alvaro, Gutierrez, Belen, Hidalgo, Laura, La Ragione, Roberto M, AbuOun, Manal, Galimand, Marc, Ferrándiz, María José, Domínguez, Lucas, de la Campa, Adela G, Gonzalez-Zorn, Bruno
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for Microbiology 01-12-2011
• Subjects: ABC transporters; adenosine triphosphate; Amino Acid Sequence; Animals; Anti-Infective Agents; Anti-Infective Agents - metabolism; Anti-Infective Agents - pharmacology; antibiotic resistance; antibiotics; Antibiotics. Antiinfectious agents. Antiparasitic agents; ATP-Binding Cassette Transporters - chemistry; ATP-Binding Cassette Transporters - genetics; ATP-Binding Cassette Transporters - metabolism; Bacillus subtilis; Bacillus subtilis - genetics; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Base Sequence; Biological and medical sciences; ciprofloxacin; Drug Resistance, Bacterial; Escherichia coli; Fluoroquinolones; Fluoroquinolones - metabolism; Fluoroquinolones - pharmacology; gene overexpression; genes; Gram-positive bacteria; Humans; loci; Mechanisms of Resistance; Medical sciences; Microbial Sensitivity Tests; Molecular Sequence Data; new methods; norfloxacin; Oligonucleotide Array Sequence Analysis; pathogens; Pharmacology. Drug treatments; Phenotype; plasmids; Polymerase Chain Reaction; reserpine; Sequence Analysis, DNA; Streptococcus suis; Streptococcus suis - drug effects; Streptococcus suis - metabolism; Streptococcaceae; Bacteria; Micrococcales; Fluoroquinolone derivatives; Antibacterial agent; Streptococcus suis
• ISSN: 0066-4804; 1098-6596
• DOI: 10.1128/AAC.00498-11

Streptococcus suis is an emerging zoonotic pathogen. With the lack of an effective vaccine, antibiotics remain the main tool to fight infections caused by this pathogen. We have previously observed a reserpine-sensitive fluoroquinolone (FQ) efflux phenotype in this species. Here, SatAB and SmrA, two pumps belonging to the ATP binding cassette (ABC) and the major facilitator superfamily (MFS), respectively, have been analyzed in the fluoroquinolone-resistant clinical isolate BB1013. Genes encoding these pumps were overexpressed either constitutively or in the presence of ciprofloxacin in this strain. These genes could not be cloned in plasmids in Escherichia coli despite strong expression repression. Finally, site-directed insertion of smrA and satAB in the amy locus of the Bacillus subtilis chromosome using ligated PCR amplicons allowed for the functional expression and study of both pumps. Results showed that SatAB is a narrow-spectrum fluoroquinolone exporter (norfloxacin and ciprofloxacin), susceptible to reserpine, whereas SmrA was not involved in fluoroquinolone resistance. Chromosomal integration in Bacillus is a novel method for studying efflux pumps from Gram-positive bacteria, which enabled us to demonstrate the possible role of SatAB, and not SmrA, in fluoroquinolone efflux in S. suis.