First Characterization of CTX-M-15-Producing Escherichia coli Strains Belonging to Sequence Type (ST) 410, ST224, and ST1284 from Commercial Swine in South America

Abstract

T he rapid spread of the bla CTX-M-15 gene, which encodes the currently most widely distributed extended-spectrum ␤-lactamase (ESBL) enzyme in Gram-negative bacteria, is a global challenge to human and veterinary medicine. In this context, foodproducing animals have acquired an important role as reservoirs for CTX-M-15-producing bacteria, which can be transmitted to the community (1, 2). In this report, we describe for the first time the isolation of CTX-M-15-producing Escherichia coli in commercial swine in Brazil, highlighting a new reservoir of CTX-M-15-producing isolates with zoonotic potential in South America.In 2012, during a study conducted to assess the occurrence of ESBL-producing bacteria in swine production, eight (3%) ceftiofur-resistant CTX-M-15-producing E. coli isolates were recovered from 267 fecal swabs collected from male and female nursery (40 days) and finishing (90 days) pigs from 28 farms in seven Brazilian states. In this regard, ceftiofur-resistant strains were isolated by using MacConkey agar supplemented with 2 g/ml of ceftiofur. E. coli isolates were identified by the MALDI Biotyper (Bruker Daltonics, Germany), and the antibiotic resistance profiles were determined by the Kirby-Bauer method, with MICs determined by the microdilution technique by using Sensititre ESBL-confirmatory MIC plates (Trek Diagnostic Systems, Thermo Fisher) and/or the agar dilution method (3, 4). ESBL production was screened by the double-disk synergy test, and the presence of bla CTX-M -type genes was examined by PCR amplification and sequencing. E. coli isolates were further characterized by phylogenetic grouping (5) and multilocus sequence typing (MLST) (http: //mlst.warwick.ac.uk/mlst/dbs/Ecoli). Next, plasmids were extracted and used to transform electrocompetent E. coli TOP10 recipient cells (Invitrogen) by electroporation. The transformant E. coli TOP10 strains were selected on Mueller-Hinton agar supplemented with 2 g/ml of cefotaxime and further analyzed by replicon typing (6), plasmid MLST experiments (http://pubmlst .org/plasmid/), and partial plasmid sequencing to elucidate the bla CTX-M-15 genetic environment.The eight ceftiofur-resistant E. coli isolates produced CTX-M-15 and exhibited high MICs of human and veterinary cephalosporins (Table 1). Additionally, E. coli strains were resistant to ciprofloxacin, enrofloxacin, norfloxacin, tetracycline, sulfonamide-trimethoprim, and gentamicin (7). Otherwise, all isolates remained susceptible to amikacin, cephamycins, and carbapenems. The isolates belonged to three clonal lineages of sequence type (ST) 224 (5 strains from farm X in Minas Gerais State, southeastern Brazil), ST410 (CC23; 1 strain from farm Y in Minas Gerais State), and ST1284 (2 strains from farm Z in Paraná State, southern Brazil). While none of the eight isolates belonged to phylogroup B2, phylogroups A and B1 were identified among CTX-M-15-producing E. coli strains. For E. coli ST224 and ST410 strains, the bla CTX-M-15 gene was successfully transferred to TOP10 E. coli isolates by trans...

The Occurrence and Characterization of Extended-Spectrum-Beta-Lactamase-Producing Escherichia coli Isolated from Clinical Diagnostic Specimens of Equine Origin

“…Notably, both ST10 and ST224 previously demonstrated their capacity for nosocomial infections and the spread of these sequence types between horses and potentially, to their human handlers [14,18,19]. In addition to being recovered from horses [14], ST224 was isolated from humans [11], swine [42], bovines [47], birds [44], and in this study, from a donkey. ST167 E. coli was isolated from humans, cattle, swine, wild birds [34,46,48], turkey meat [43], and horses [49].…”

“…ST410, which was identified in 3 of the 13 E. coli isolates, has also been described as an emerging high-risk E. coli with potential international implications [37]. ST410 was previously isolated from humans [38,39], canines, felines [40], swine, poultry, cattle [41][42][43], as well as birds [44]. E. coli ST10, identified in two of the 13 isolates, was recovered from humans, turkey meat, chickens, swine, cattle [45,46], and horses [19,20].…”

Antimicrobial Resistance in Farm Animals in Brazil: An Update Overview

“…In contrast, Silva et al reported eight isolates obtained in 2012 also in the same state from pig fecal swabs resistant to third-and fourth-generation cephalosporins, associated with the occurrence of the ESBL encoding gene bla CTX-M-15 . These isolates were also resistant to ciprofloxacin, enrofloxacin, norfloxacin, tetracycline, sulfonamide-trimethoprim, and gentamicin, being sensitive only to amikacin, cephamycins, and carbapenems [87].…”

Whole-genome comparative analysis of carbapenem-resistant Escherichia coli isolated from hospitalized patients in Lebanon

“…Sequences correlating to IncA/C2, IncFIA, IncFIB, IncFII, IncI1, IncQ1, IncX3, IncX4, Col(BS512) and Col156 plasmids were identified, with incompatibility groups IncFIA and IncFIB being present in all isolates (Table 12). The widespread emergence of the blaCTX-M-15 gene, which is frequently interrelated with TEM-1, OXA-1 and aac(6')-Ib-cr, was mainly linked to IncF replicons (Carattoli, 2009 (Carattoli, 2009 andSilva et al, 2016), all of which were in harmony with this study's results (Table 6 and 11). Furthermore, ECC 167 and ECC 194 carried the pBS512_2 plasmid, which is linked to type III secretion system (Villa et al, 2010).…”

“…ST-1284 (CC10) E. coli isolates were CTX-M-15 producers (Novais et al, 2012), which was similar to ECC 167 (ST-1284) (Table 11). E. coli ST-1284 was previously isolated from raw milk in Algeria (Yaici et al, 2016) and commercial swine in Brazil (Silva et al, 2016). However, to the best of our knowledge, this is the first isolation and Korea (human) .…”