title: Genetic and physiological characterization of oxytetracycline-resistant bacteria from giant prawn farms.
abstract: Four hundred and thirteen oxytetracycline-resistant bacteria were recovered from six freshwater giant prawn farms with a history of oxytetracycline use. Most oxytetracyclineresistant isolates were Gram-negative bacteria. Six groups of oxytetracycline-resistant bacteria were classified using cluster analysis based on a comparison of levels of oxytetracycline resistance. Complex fingerprint patterns were obtained for 71 isolates studied. In general, the band patterns of isolates from different ponds were very similar, and the data indicated that the isolates were closely related. The exploration for crossresistance found that most of the 71 oxytetracycline-resistant isolates were also resistant to tetracycline and chlortetracycline, but had a relatively low resistance to doxycycline. Many isolates showed higher chlortetracycline resistance than oxytetracycline resistance. Additionally, the oxytetracyclineresistant isolates were examined for the presence of tetracycline resistance (tet) genes. Fifty percent of the isolates carried one of the 14 known tet genes examined. The most common determinants were TetA and TetD. However, TetB, TetC, TetE, TetK, TetL, and TetM were also found with various frequencies.
authors.affiliation: Department of Soil Science, Kasetsart University, Cha-tuchak, Bangkok 10900, Thailand.
authors.forename: Pimpak
authors.initials: P
authors.lastname: Heepngoen
authors.forename: Kannika
authors.initials: K
authors.lastname: Sajjaphan
authors.forename: John A
authors.initials: JA
authors.lastname: Ferguson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sadowsky
mesh_terms: D000818:Animals; D017756:Aquaculture; D001419:Bacteria / Q000145:classification* / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics; D016172:DNA Fingerprinting; D024901:Drug Resistance, Multiple, Bacterial; D019015:Geologic Sediments / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D010118:Oxytetracycline / Q000031:analogs & derivatives / Q000494:pharmacology*; D033541:Palaemonidae / Q000382:microbiology*; D012988:Soil Microbiology; D013753:Tetracycline Resistance; D014871:Water Microbiology
chemical_list: D001426:Bacterial Proteins; D010118:Oxytetracycline