title: Escherichia coli tetracycline efflux determinants in relation to tetracycline residues in chicken.
abstract: OBJECTIVE
  To screen for Escherichia coli (E. coli) resistant to tetracycline, followed by identification of tet efflux genes by polymerase chain reaction (PCR). In addition, detection of tetracycline residues in chicken livers and kidneys were conducted using high performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS).
  
  
  METHODS
  Strains of E. coli were isolated from samples of chicken colon and screened for tetracycline resistance. Tetracycline genes conferring resistance (Tc(r)) were detected by polymerase chain reaction (PCR). Most of the isolates were resistant to tetracycline (97.9%).
  
  
  RESULTS
  PCR analysis indicated that Tc(r)E. coli R-plasmids contained tet(A), tet(B) and a combination of both efflux genes. None of the isolates contained other efflux tet genes tet (C, D, E and Y). High performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS), a sensitive technique, was used to detect residues of chlortetracycline (CTC), oxytetracycline (OTC), doxycycline (DC) in chicken livers and kidneys. The samples containing tetracycline residues were at 0.13-0.65 pg/μL levels.
  
  
  CONCLUSIONS
  Tetracycline and other antibiotics are commonly used in the poultry and meat production industry for prevention of microbial infections. Multiple antibiotic resistant bacteria in Oman have increased to alarming levels, threatening public health, domestic and may have adverse effect on environment.
authors.affiliation: Department of Biology, College of Science, Sultan Qaboos University, P.O.Box 36, P.C. 123, Al-Khodh Muscat, Oman. snbahry@squ.edu.om
authors.forename: Al-Bahry
authors.initials: AB
authors.lastname: S N
authors.forename: Al-Mashani
authors.initials: AM
authors.lastname: B M
authors.forename: Al-Ansari
authors.initials: AA
authors.lastname: A S
authors.forename: Elshafie
authors.initials: E
authors.lastname: A E
authors.forename: Mahmoud
authors.initials: M
authors.lastname: I Y
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000378:metabolism / Q000494:pharmacology; D017920:Antiporters / Q000235:genetics* / Q000378:metabolism; D002645:Chickens; D004350:Drug Residues / Q000032:analysis* / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis*; D008460:Meat / Q000032:analysis* / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D013752:Tetracycline / Q000032:analysis* / Q000378:metabolism / Q000494:pharmacology; D013753:Tetracycline Resistance
chemical_list: D000900:Anti-Bacterial Agents; D017920:Antiporters; D029968:Escherichia coli Proteins; D013752:Tetracycline
keywords: Antibiotic resistance genes; Chicken; Escherichia coli; Tetracycline