Mechanisms of antibiotic resistance in Escherichia coli isolates recovered from wild animals.
Seventy-two fecal samples obtained from wild animals in Portugal were sampled on Levine agar plates (non-supplemented with antibiotics), and Escherichia coli isolates were recovered from 56 of them (78%), obtaining a total of 112 E. coli isolates (two per sample). Susceptibility to 16 antibiotics was studied in these isolates, and the following percentages of resistance were obtained: tetracycline, streptomycin, ampicillin, and trimethoprim-sulfamethoxazole (SXT) (range 19-35%); nalidixic acid (14%); ciprofloxacin (9%); amoxicillin-clavulanic acid, gentamicin, tobramycin, and chloramphenicol (range 4.5-7%); cefotaxime, and aztreonam (1.8%); ceftazidime (0.9%); and amikacin, cefoxitin, and imipenem (0%). A bla(TEM) gene was found in 22 of the 25 ampicillin-resistant isolates, and the gene encoding CTX-M-14 beta-lactamase was identified in the two cefotaxime-resistant isolates (recovered from a common kestrel and a sparrowhawk), associated with bla(TEM-52) gene in one of them. Other resistance genes detected were as follows: aac(3)-II or aac(3)-IV genes in all gentamicin-resistant isolates; aadA1 or aadA2 in 22 of 25 streptomycin-resistant isolates; tet(A) and/or tet(B) in all 39 tetracycline-resistant isolates; and sul1 and/or sul2 and/or sul3 genes in all 21 SXT-resistant isolates. Two amino acid changes in GyrA protein (Ser83Leu + Asp87Asn) and one change in ParC protein (Ser80Ile) were identified in all 10 ciprofloxacin-resistant isolates of our series. The intestinal tract of wild animals is a reservoir of antibiotic resistance genes, especially for ampicillin, tetracycline, streptomycin, and SXT, and it is also remarkable that multiresistant E. coli isolates are detected in some of the tested animals.
Costa
Daniela
D
Departamento de Ciências Veterinárias, Universidade de Trás-os-Montes e Alto Douro, Vila Real, Portugal.
Poeta
Patricia
P
Sáenz
Yolanda
Y
Vinué
Laura
L
Coelho
Ana Cláudia
AC
Matos
Manuela
M
Rojo-Bezares
Beatriz
B
Rodrigues
Jorge
J
Torres
Carmen
C
D000818:Animals; D000835:Animals, Wild / Q000382:microbiology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D011174:Portugal; D018440:beta-Lactam Resistance / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics
D000900:Anti-Bacterial Agents; D001618:beta-Lactamases