Incidence of Class 1 Integrons in a Quaternary Ammonium Compound-Polluted Environment

• DOI: 10.1128/aac.49.5.1802-1807.2005
• Publication Date: 2005-04-26T23:32:47Z
• Authors: W. H. Gaze; N. Abdouslam; P. M. Hawkey; E. M. H. Wellington
• Keywords: 2. Zero hunger; 0301 basic medicine; Bacteria; Cetrimonium; Reverse Transcriptase Polymerase Chain Reaction; Colony Count, Microbial; Drug Resistance; 6. Clean water; Integrons; Quaternary Ammonium Compounds; 03 medical and health sciences; Genes, Bacterial; Cetrimonium Compounds; Environmental Pollutants; Environmental Pollution

ABSTRACTSamples of effluent and soil were collected from a reed bed system used to remediate liquid waste from a wool finishing mill with a high use of quaternary ammonium compounds (QACs) and were compared with samples of agricultural soils. Resistance quotients of aerobic gram-negative and gram-positive bacteria to ditallowdimethylammomium chloride (DTDMAC) and cetyltrimethylammonium bromide (CTAB) were established by plating onto nutrient agar containing 5 μg/ml or 50 μg/ml DTDMAC or CTAB. Approximately 500 isolates were obtained and screened for the presence of theintI1(class 1 integrase),qacE(multidrug efflux), andqacEΔ1(attenuatedqacE) genes. QAC resistance was higher in isolates from reed bed samples, and class 1 integron incidence was significantly higher for populations that were preexposed to QACs. This is the first study to demonstrate that QAC selection in the natural environment has the potential to coselect for antibiotic resistance, as class 1 integrons are well-established vectors for cassette genes encoding antibiotic resistance.