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Research Support, Non-U.S. Gov't
- Prevalence of Tetracycline Resistance Genes in Greek Seawater Habitats
- Theodora L. Nikolakopoulou , Eleni P. Giannoutsou , Adamandia A. Karabatsou , Amalia D. Karagouni
- J. Microbiol. 2008;46(6):633-640. Published online December 24, 2008
- DOI: https://doi.org/10.1007/s12275-008-0080-8
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Abstract
- The presence of selected tetracycline resistance (TcR) genes was studied in different Greek seawater habitats, originated from wastewater treatment facilities, fishfarm, and coastal environments. The methods employed included assessment of the presence of twelve gene clusters by PCR, followed by hybridization with specific probes, in habitat extracted DNA, TcR bacteria, and exogenous isolated plasmids conferring TcR. The direct DNA-based analysis showed that tet(Α) and tet(K) genes were detected in all habitats, whilst tet(C) and tet(E) were present in fishfarm and wastewater effluent samples and tet(M) was detected in fishfarm and coastal samples. Resistance genes tet(A), tet(C), tet(K), and tet(M) were detected in 60 of the 89 isolates screened. These isolates were identified by fatty acid methyl ester analysis (FAME) as Stenotrophomonas, Acinetobacter, Pseudomonas, Bacillus, and Staphylococcus strains. The presence of the TcR genes in 15% of the bacterial isolates coincided with the presence of IncP plasmids. A habitat-specific dissemination of IncP alpha plasmids in wastewater effluent isolates and of IncP beta plasmids in fishfarm isolates was observed. Exogenous isolation demonstrated the presence of plasmids harbouring TcR genes in all the habitats tested. Plasmids were shown to carry tet(A), tet(C), tet(E), and tet(K) genes. It is concluded that TcR genes are widespread in the seawater habitats studied and often occur on broad host range plasmids that seem to be well disseminated in the bacterial communities.
- Methods of the extraction of DNA from water samples for polymerase chain reaction
- Jung, Hae Sung , Lee, Young Jong
- J. Microbiol. 1997;35(4):354-359.
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Abstract
- Methods for the extraction of DNA from water sample were approximated. Four different procedures of DNA extraction were carried out with pellets obtained from centrifugation of 4 liter water samples. The recovery efficiency and purity of DNA extracted by each method from different sources were compared. DNA yield varied with extraction methods, Method I, which involves enzymatic and freeze-thaw lysis steps and phenol and phenol-chloroform purification of extracted nucleic acid, showed a significantly higher yield and purity than the other methods. The use of glass beads in the DNA extraction methods improved the purity of DNA suitable for PCR. Bovine serum albumin in the PCR reaction mixture was useful in reducing inhibitory effects of contaminants. The efficiency of an extraction method was determined by the detection of the aer of Aeromonas hydrophila with PCR. The lower limit of detection of A. hydrophila from seeded tap water was 2 CFU/ml in PCR when method I was used for DNA preparation.
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