Unexpected distribution of the fluoroquinolone-resistance gene qnrB in Escherichia coli isolates from different human and poultry origins in Ecuador.
Fluoroquinolone resistance can be conferred through chromosomal mutations or by the acquisition of plasmids carrying genes such as the quinolone resistance gene (qnr). In this study, 3,309 strains of commensal Escherichia coli were isolated in Ecuador from: (i) humans and chickens in a rural northern coastal area (n = 2368, 71.5%) and (ii) chickens from an industrial poultry operation (n = 827, 25%). In addition, 114 fluoroquinolone-resistant strains from patients with urinary tract infections who were treated at three urban hospitals in Quito, Ecuador were analyzed. All of the isolates were subjected to antibiotic susceptibility screening. Fluoroquinolone-resistant isolates (FRIs) were then screened for the presence of qnrB genes. A significantly higher phenotypic resistance to fluoroquinolones was determined in E. coli strains from chickens in both the rural area (22%) and the industrial operation (10%) than in strains isolated from humans in the rural communities (3%). However, the rates of qnrB genes in E. coli isolates from healthy humans in the rural communities (11 of 35 isolates, 31%) was higher than in chickens from either the industrial operations (3 of 81 isolates, 6%) or the rural communities (7 of 251 isolates, 2.8%). The occurrence of qnrB genes in human FRIs obtained from urban hospitals was low (1 of 114 isolates, 0.9%). These results suggested that the qnrB gene is more widely distributed in rural settings, where antibiotic usage is low, than in urban hospitals and industrial poultry operations. The role of qnrB in clinical resistance to fluoroquinolones is thus far unknown.
Institute of Microbiology, Biological and Environmental Sciences College, University San Francisco de Quito, Quito, Ecuador.
Paulina I
PI
Armas-Freire
Institute of Microbiology, Biological and Environmental Sciences College, University San Francisco de Quito, Quito, Ecuador.
Gabriel
G
Trueba
Institute of Microbiology, Biological and Environmental Sciences College, University San Francisco de Quito, Quito, Ecuador.
Carolina
C
Proaño-Bolaños
Department of Environmental Health, Emory University, Atlanta, USA.
Karen
K
Levy
Department of Epidemiology, University of Michigan, Ann Arbor, USA.|Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, USA.
Lixin
L
Zhang
Department of Epidemiology, University of Michigan, Ann Arbor, USA.
Carl F
CF
Marrs
Institute of Biomedicine, Central University of Ecuador, Quito, Ecuador.
William
W
Cevallos
Department of Epidemiology, University of Michigan, Ann Arbor, USA.
Joseph N S
JN
Eisenberg
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002645:Chickens; D024881:Drug Resistance, Bacterial; D004484:Ecuador; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000662:veterinary*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010802:Phylogeny; D011201:Poultry Diseases / Q000382:microbiology*
D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D024841:Fluoroquinolones
Escherichia coli; gene qnrB; industral poultry operations; quinolone resistance; urban hospitals