Molecular Epidemiology of Dairy Cattle-Associated Escherichia coli Carrying bla _CTX-M Genes in Washington State

Abstract

An increase in the prevalence of commensal carrying genes among dairy cattle was observed between 2008 and 2012 in Washington State. To study the molecular epidemiology of this change, we selected 126 -positive and 126-negative isolates for determinations of the multilocus sequence types (MLSTs) and antibiotic resistance phenotypes from obtained during a previous study. For 99 isolates, we also determined the alleles using PCR and sequencing and identified the replicon types of -carrying plasmids. The-negative isolates comprised 76 sequence types (STs) compared with 32 STs in-positive isolates. The-positive isolates formed three MLST clonal complexes, accounting for 83% of these isolates; 52% of-negative isolates clustered into 10 clonal complexes, and the remainder were singletons. Overall,-negative isolates had more diverse genotypes that were distinct to farms, whereas-positive isolates had a clonal population structure and were widely disseminated on farms in both regions included in the study. Plasmid replicon types included IncI1 which predominated, followed by IncFIB and IncFIA/FIB. was the predominant CTX-M gene allele, followed by and There was no significant association between plasmid replicon types and bacterial STs, and neither clonal complexes nor major plasmid groups were associated with two discrete dairy-farming regions of Washington State. Infections caused by extended-spectrum β-lactamase (ESBL)-producing occur globally and present treatment challenges because of their resistance to multiple antimicrobial drugs. Cattle are potential reservoirs of ESBL-producing, and so understanding the causes of successful dissemination of genes in commensal bacteria will inform future approaches for the prevention of antibiotic-resistant pathogen emergence.

Characterization and virulence factors distribution of blaCTX-M and mcr-1 carrying Escherichia coli isolates from bovine mastitis

“…The major ESBL families includes CTX-M, SHV, TEM, OXA and other variants. The bla CTX-M βlactamases group has been further divided into five sub groups, (bla CTX-M1 ,bla CTX-M-2 , bla CTX-M-8 ,bla CTX-M-9 , andbla CTX-M-25 ) and more than 120bla CTX-M enzymes have been reported (Afema et al, 2018). The success of bla CTX-M lineages has been credited to several factors, such as competent mobilization and distribution of CTX-M genes by mobile genetic elements MGEs (plasmids, transposon and insertion elements) (D'Andrea, Arena, Pallecchi, & Rossolini, 2013).…”

Multidrug Resistant <em>Escherichia</em><em> coli</em> Harboring Extended-spectrum β-lactamase-encoding Genes Isolated from Clinically-healthy Pigs

“…The rise in the occurrence and spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is currently a global emergency. These pathogens constitute a significant threat to the efficacy of many antimicrobials including 3 rd and 4 th generation cephalosporins [1,2]. Evidently, acquisition of antimicrobial resistance (AMR) genes arises due to continuous and indiscriminate use of antimicrobials in food animal production [3].…”

Complete Nucleotide Sequence of a Novel Plasmid Bearing the High-Level Tigecycline Resistance Gene tet (X4)

“…Ten specific sets of primers (pir, udhA_2, silA, repB, repE, merA, sul3, floR, qnrS1, and bla TEM-1B [see Table S1 in the supplemental material]) designed to amplify the five modules from plasmid pSTB20-1T revealed that 3 isolates (THP14-1, THX8-2, and THX3-2; 7.3%) harbored all of the 9 tested genes, except for deletion of 1 gene silA in strain THX3-2. Of note, these 2 tet(X4)-carrying E. coli isolates and STB20-1 belonged to ST761, which was a predominant ST associated with dissemination of tet(X4) in our previous study (3) and bla CTX-M genes in other studies (11), although this ST seems to be uncommon overall and has been reported sporadically (12). These results indicate that there may be a low prevalence of pSTB20-1T-like plasmids in tet(X4)-carrying E. coli isolates, especially ST761.…”