Identification of Escherichia coli and Salmonella enterica organisms with reduced susceptibility to ceftriaxone from fecal samples of cows in dairy herds

Abstract

No evidence was found that the use of ceftiofur on dairy farms increases the prevalence or dissemination of Salmonella spp or E coli with reduced susceptibility to ceftriaxone.

Recent Emergence of Escherichia coli with Cephalosporin Resistance Conferred by bla CTX-M on Washington State Dairy Farms

“…We did not detect any association between farm-level antibiotic use (including ceftiofur) and farm-level CTX-M E. coli prevalence, a finding that is consistent with previous observations (44,45). A study of 65 dairy farms in the United Kingdom found a significant association between the use of a third-or fourth-generation cephalosporin in the previous 12 months and the presence of CTX-M E. coli on the farm (46).…”

Urine from Treated Cattle Drives Selection for Cephalosporin Resistant Escherichia coli in Soil

“…Our bedding exposure study clearly illustrates that transmission is feasible, and others have also reported transmission of bacteria through simple contact with the floor, hide, food and water [29], [30], [31]. Consequently, the dramatic expansion of cef R enteric bacteria in food animal populations could be explained in part through a process of environmental selection and transmission back to food animals; the effect shown here is much more dramatic than has been reported for in vivo selection following parenteral administration of ceftiofur [8], [10], [13], [14], [17]. While we designed these experiments to reflect physiologically relevant metabolites and concentrations, our bioassay only measured the biological effect of CFM, but not the actual concentration of CFM.…”

“…In the U.S. resistance to 3 rd -generation cephalosporins is most often mediated by a bla CMY-2 gene that is harbored by IncA/C plasmids in enteric bacteria [2], [3]. The prevalence of bla CMY-2 plasmid-bearing Salmonella and Escherichia coli has increased rapidly in the U.S. cattle population over the last decade [4], [5], [6], [7], [8], [9]. For instance, Daniels et al [10] found that at least 97% of dairy herds in Washington State were positive for bla CMY-2 plasmid-bearing E. coli and the U.S. Department of Agriculture [11] reported that the percentage of Salmonella sp.…”

“…Within 24 h the majority of the CFM is excreted into feces (∼30%) and urine (∼70%) [18]. CFM is degraded in cattle feces [19] and this may explain why in vivo selection of resistant enteric bacteria is limited and inconsistent in cattle [8], [10], [13], [14], [17]. Subbiah et al [20] reported that several β-lactams, including cephalosporins, remain bactericidal in soils >24 h suggesting the possibility that primary selection for cef R E. coli could occur ex vivo rather than in vivo ; if this hypothesis is correct it could indicate new opportunities to mitigate the proliferation of cef R bacteria.…”

Do antibiotic residues in soils play a role in amplification and transmission of antibiotic resistant bacteria in cattle populations?

“…Ceftiofur poses an interesting conundrum because while resistance is prevalent in E. coli and Salmonella in the U.S. (Winokur et al, 2000; Donaldson et al, 2006; Daniels et al, 2007, 2009; Sawant et al, 2007; Heider et al, 2009; Lindsey et al, 2009), empirical studies show either no treatment effect (Singer et al, 2008; Daniels et al, 2009; Mann et al, 2011) or transient and relatively short-term amplification of resistant populations (Jiang et al, 2006; Lowrance et al, 2007) after administration of ceftiofur. Lowrance et al (2007) provided the most convincing evidence that selection occurs in the gastrointestinal tract where there was a proportional increase in the number of ceftiofur-resistant E. coli following 1, 2, or 3 days administration of a ceftiofur crystalline-free acid product.…”