Hierarchal clustering yields insight into multidrug-resistant bacteria isolated from a XXXX feedlot wastewater treatment system.

@entity801 @entity2756 @entity2176 @entity8588 @entity7913 @entity11686 @entity2929 @entity4509 @entity6186 @entity2886 @entity32225 @entity13757 @entity581 @entity5136 @entity291 @entity526
Forty-two percent of @entity526 and 58% of Enterococcus spp. isolated from @entity291 feedlot runoff and associated infiltration basin and constructed wetland treatment system were resistant to at least one antibiotic of clinical importance; a high level of multidrug resistance (22% of @entity526 and 37% of Enterococcus spp.) was observed. Hierarchical clustering revealed a closely associated resistance cluster among drug-resistant @entity526 isolates that included @entity2886 (ceftiofur, cefoxitin, and @entity2756 ), @entity581 ( @entity801 , @entity7913 , and @entity4509 ), and quinolone nalidixic acid; antibiotics from these classes were used at the study site, and cross-resistance may be associated with transferrable multiple-resistance elements. For Enterococcus spp., co-resistance among @entity2176 , @entity5136 , and @entity13757 was common; these antibiotics are reserved for complicated clinical infections and have not been approved for animal use. @entity2176 resistance (n   =   49) only occurred when isolates were resistant to @entity5136 , @entity13757 , and all four of the MLSB (macrolide-lincosamide-streptogramin B) antibiotics tested ( @entity8588 , @entity2929 , @entity6186 , and quinipristin/ @entity11686 ). This suggests that developing co-resistance to MLSB antibiotics along with cyclic lipopeptides and @entity32225 may result in resistance to @entity2176 as well. Effects of the treatment system on antibiotic resistance were pronounced during periods of no rainfall and low flow (long residence time). Increased hydraulic loading (short residence time) under the influence of rain caused antibiotic-resistant bacteria to be flushed through the treatment system. This presents concern for environmental discharge of multidrug-resistant organisms relevant to public health.
