Genetic Diversity and New Sequence Types of Escherichia coli Coharboring β-Lactamases and PMQR Genes Isolated from Domestic Dogs in Central Panama

Abstract

Background: β-lactamase-producing Escherichia coli are a widely distributed source of antimicrobial resistance for animals and humans. Little is known about the susceptibility profile and genetic characteristics of E. coli strains isolated from domestic dogs in Latin America. Methods: We report on a cross-sectional study that evaluated E. coli strains isolated from fecal samples of domestic dogs in central Panama. The extended-spectrum β-lactamase (ESBL), AmpC genes, and plasmid-mediated quinolone resistance were investigated. Molecular typing using Pasteur’s multilocus sequence typing (MLST) was conducted. Results: A total of 40 E. coli isolates were obtained, of which 80% (32/40) were resistant to at least one of the antibiotics tested, while 20% (8/40) were sensitive to all antibiotics analyzed in this study (p < 0.001). Forty percent of the strains were resistant to three or more antibiotics. The most common resistance was to tetracycline (45%) and ampicillin (30%) while 2.5% showed an ESBL phenotype. Antibiotic resistance genes were detected for one β-lactamase (blaTEM-1) and two plasmid-mediated quinolone resistance (PMQR) enzymes (qnrS and qnrB). In addition, mutations in the chromosomal AmpC gene were observed at positions −35, −28, −18, −1, and +58. Fourteen different sequence types (STs) were identified; the most frequent were ST399 and ST425 (12% each). ST3 and ST88, which have been previously identified in human clinical isolates, were also evidenced. Three new STs were found for the first time: ST1015, ST1016 (carrier of the blaTEM-1 gene), and ST1017 (carrier of the blaTEM-1, qnrS, and qnrB genes). Conclusions: In the intestinal strains of E. coli isolated from domestic dogs, there was a high frequency of resistance to antibiotics. The presence of genes from plasmids and chromosomal mutations that conferred antibiotic resistance, the identification of isolates previously reported in humans, and the genetic diversity of STs (including three that were newly identified) confirmed the determinants of resistance to antibiotics in the domestic dogs from central Panama.

Multidrug-resistant phenotypes of genetically diverse Escherichia coli isolates from healthy domestic cats.

“…For example, in Brazil and Argentina, ST90, ST457, and ST131 have been identi ed as the most predominant [12][13] . In our study, ST399 was the most prevalent and interestingly, this same ST was mostly identi ed in a study of E. coli strains isolated from healthy dogs in central Panama 17 , which could be due to the close coexistence of dogs and cats in the same households. Likewise, ST399 has been described in isolates from dogs and cats in Oceania and Asia 16 .…”

“…The ST88 identi ed in this study has been previously reported in clinical isolates from hospitalized patients in our country 26 and also in isolates from healthy dogs 17 , which allows us to infer that there may be exchange of E. coli strains carrying genes of resistance between owners, pets, and the environment 27 . ST132 and ST83 presented the expression of PMQR genes, with ST83 presenting coexpression of resistance genes qnrB and qnrS.…”

“…Globally, no signi cant differences have been observed between the prevalence of ESBL between dogs and cats. Similarly in Panama, a previous study conducted on E. coli strains isolated from healthy dogs identi ed an 8% ESBL phenotype 17 . Worldwide, the most identi ed ESBL genotypes are blaCTX-M, blaSHV, and blaTEM, which are uniformly distributed between dogs and cats.…”

“…This nding is of particular concern, due to the potential for opportunistic infections, zoonotic transmission, and transmission of antibiotic-resistant determinants from commensal isolates to potential pathogenic bacteria 21 . MDR E. coli strains have been previously described in studies carried out in healthy domestic animals [13][14][15][16][17][18] as well as from environmental strains 22 . This aspect has varied in diverse countries where regulatory standards based on non-prescription antibiotics used in veterinary medicine have been regulated due to the emergence of MDR strains 23 .…”

“…The isolates based on the resistance phenotype to β-lactams, quinolones and carbapenems were analyzed by PCR to determine the presence of blaCTX-M, blaTEM, blaSHV, blaAMPC, blaEBC, blaMOX, and blaACC genes [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] . The fragments obtained from the PCR product were analyzed by electrophoresis in a 1.5% agarose gel and visualized under ultraviolet light.…”