Coastal Seawater Bacteria Harbor a Large Reservoir of Plasmid-Mediated Quinolone Resistance Determinants in Jiaozhou Bay, China

• Published in: Microbial ecology 2012-07, Vol.64 (1), p.187-199
• Main Authors: Zhao, Jing-yi, Dang, Hongyue
• Format: Article
• Language: English
• Subjects: Algae; Anti-Bacterial Agents - pharmacology; Antibiotic resistance; Antibiotics; Bacteria; Bacteria - classification; Bacteria - drug effects; Bacteria - genetics; Bacteria - isolation & purification; Bacterial Proteins - genetics; Bays - microbiology; Biological and medical sciences; Biomedical and Life Sciences; China; Citrobacter freundii; Drug Resistance, Bacterial; E coli; Ecology; Enterobacter; ENVIRONMENTAL MICROBIOLOGY; Escherichia coli; Fundamental and applied biological sciences. Psychology; Genes; Genotypes; Geoecology/Natural Processes; Klebsiella; Life Sciences; Microbial Ecology; Microbial Sensitivity Tests; Microbiology; Molecular Sequence Data; Nature Conservation; Phylogeny; Plasmids; Plasmids - genetics; Plasmids - metabolism; Proteus vulgaris; Pseudoalteromonas; Pseudomonas; Quinolones; Quinolones - pharmacology; Reservoirs; Sea water; Seawater; Seawater - microbiology; Shewanella; Water Quality/Water Pollution
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-012-0008-z

Diversity and prevalence of plasmid-mediated quinolone resistance determinants were investigated in environmental bacteria isolated from surface seawater of Jiaozhou Bay, China. Five qnr gene alíeles were identified in 34 isolates by PCR amplification, including qnrA3 gene in a Shewanella algae isolate, qnrB9 gene in a Citrobacter freundii isolate, qnrD gene in 22 Proteus vulgaris isolates, qnrS1 gene in 1 Enterobacter sp. and 4 Klebsiella spp. isolates, and qnrS2 gene in 1 Pseudomonas sp. and 4 Pseudoalteromonas sp. isolates. The qnrC, aac(6')-Ib-cr, and qepA genes could not be detected in this study. The 22 qnrD-positive Proteus vulgaris isolates could be differentiated into four genotypes based on ERIC-PCR assay. The qnrS1 and qnrD genes could be transferred to Escherichia coli J53 Azi R or E. coli TOP10 recipient strains using conjugation or transformation methods. Among the 34 qnr-positive isolates, 30 had a single point mutation in the QRDRs of GyrA protein (Ala67Ser, Ser83I1e, or Ser83Thr), indicating that cooperation of chromosome-and plasmidmediated resistance contributed to the spread and evolution of quinolone resistance in this coastal bay. Eighty-five percent of the isolates were also found to be resistant to ampi cillin, and bla CMY , bla OXY , bla SHV and bla TEM genes were detected in five isolates that also harbored the qnrB9 or qnrS1 gene. Our current study is the first identification of qnrS2 gene in Pseudoalteromonas and Pseudomonas strains, and qnrD gene in Proteus vulgaris strains. High prevalence of diverse qnr genes in Jiaozhou Bay indicates that coastal seawater may serve as an important reservoir, natural source, and dissemination vehicle of quinolone resistance determinants.