Dissemination of Multidrug-Resistant Commensal Escherichia coli in Feedlot Lambs in Southeastern Brazil

Abstract

Antimicrobial resistance (AR) is a public health issue since it limits the choices to treat infections by Escherichia coli in humans and animals. In Brazil, the ovine meat market has grown in recent years, but studies about AR in sheep are still scarce. Thus, this study aims to investigate the presence of AR in E. coli isolated from lambs during feedlot. To this end, feces from 112 lambs with 2 months of age, after weaning, were collected on the first day of the animals in the feedlot (day 0), and on the last day before slaughtering (day 42). Isolates were selected in MacConkey agar supplemented with 4 mg/L of ceftiofur and identified by biochemical methods. Isolates were submitted to an antimicrobial susceptibility test by disc-diffusion and PCR to investigate genes for phylogenetic group, virulence determinants and resistance to the several antimicrobial classes tested. The genetic localization of the bla genes detected was elucidated by S1-PFGE followed by Southern blot-hybridizations. The isolates were typed by XbaI-PFGE and MLST methods. Seventy-eight E. coli were isolated from 8/112 (7.1%) animals on day 0, and from 55/112 (49.1%) animals on day 42. Since only fimH was present in almost all E. coli (97.4%) as a virulence gene, and also 88.5% belonged to phylogroups B1 or A, we consider that isolates represent intestinal commensal bacteria. The dendrogram separated the 78 non-virulent isolates in seven clusters, two of which comprised 50 E. coli belonging to ST/CC 1727/446 or ST 3994 recovered on day 42 commonly harboring the genotype bla CMY−2-aac(3)-IIa-tetA-sul1-sul2-floR-cmlA. Special attention should be given to the presence of bla CTX−M−15 , a worldwide gene spread, and bla CTX−M−14 , a hitherto undetected gene in Enterobacteriaceae from foodproducing animals in Brazil. Importantly, E. coli lineages and plasmids carrying bla genes detected here have already been reported as sources of infection in humans either from animals, food, or the environment, which raises public health concerns. Hence, two types of commensal E. coli carrying important AR genes clearly prevailed during feedlot, but lambs are also reservoirs of bacteria carrying important AR genes such as bla CTX−M−14 and bla CTX−M−15 , mostly related to antimicrobial treatment failure.

Broad-Spectrum Cephalosporin-Resistant and/or Fluoroquinolone-Resistant Enterobacterales Associated with Canine and Feline Urogenital Infections

“…One E. coli isolated from the vagina of a dog has been typed as B1-ONT:H7-ST1642-CH11-54 (TEM). The same ST (B1-O8:H7-ST1642) harboring CTX-M-55 has been isolated from a urine specimen of a cat in Japan [31], the CTX-M-14 harboring variant has been detected in human blood samples [40], the CTX-M-15 variant has been found in feces of healthy lambs in Brazil [30] and the E. coli B1-ST1642 harboring bla TEM and bla CMY has been detected in an intestinal specimen from a stray dog in South Korea [23].…”

“…Despite carbapenems have no legal indication in some countries and are not used in routine practice, ISCAID and other relevant institutions have included carbapenems in their official documentation related to animals [18,29]. Close contact between humans and companion animals contributes to the propagation and exchange of resistance genes between bacteria as well as the direct transmission of all ExPEC subcategories including UPECs, so human-related clones have already been detected in companion animals [27,[30][31][32]. As a consequence, companion animals are more and more considered an important source of human infections both by ExPEC/UPEC and by multidrug-resistant bacteria (MDR) in general [20,26,[33][34][35][36].…”

Identification of CTX-M Type ESBL E. coli from Sheep and Their Abattoir Environment Using Whole-Genome Sequencing

“…Dissemination of ESBL E. coli in livestock farm-related environments such as soil, water, manure, air, dust, feed, etc., have recently been reviewed [16]. Although betalactamase genes including bla CTX-M-1 , bla CTX-M-2 , bla CTX-M-3 , bla CTX-M-8 , bla CTX-M-14 and bla CTX-M-15 , bla SHV , bla TEM, and bla CMY-2 were detected in feces of sheep and retail lamb in other parts of the world [10,[17][18][19][20], there is no report available on AMR determinants of ESBL E. coli in small ruminants in the U.S. Therefore, to fill this gap in information, we conducted a study to detect and characterize AMR determinants using WGS in ESBL E. coli recovered from sheep and their abattoir environment in North Carolina.…”

Whole Genome Sequencing Differentiates Presumptive Extended Spectrum Beta-Lactamase Producing Escherichia coli along Segments of the One Health Continuum

“…Since the present study investigated only presumptive ESBL-EC, it is possible that tet(M) may be present in the selected ESBL-EC subpopulation of the feedlot environment, likely acquired through horizontal gene transfer (HGT) as proposed by Bryan et al [58,62]. The predominance of sul2, aph(3")-Ib, aph(6)-Id, and floR has also been previously observed in cattle-and human-sources [63][64][65]. These resistances seem to arise with AMU and likely EHA is supported by the University of Manitoba PhD Graduate Fellowship.…”