Seventy-two fecal samples obtained from wild animals in Portugal were sampled on Levine agar plates (nonsupplemented 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 β-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.

The objective was to determine the location of bla _CTX-M-1 and bla _CMY-2 genes in 33 Escherichia coli isolates previously obtained from healthy humans, pets, and food-producing animals in Tunisia, and to characterize the genetic lineages of isolates. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE)- Xba I and multilocus sequence typing (MLST). Plasmids were analyzed by S1-PFGE, polymerase chain reaction-based replicon typing, and plasmid MLST. Conjugation experiments were performed. The bla _CTX-M-1 and bla _CMY-2 genes were studied by I-Ceu1-PFGE and S1-PFGE, and subsequent hybridization with specific probes. Eighteen different sequence types (STs) were identified among the 30 CTX-M-1-producing isolates, 5 of them being detected in 17 isolates (ST/phylogroup): ST57/D, ST155/B1, ST58/B1, ST10/A, and ST398/A. Most of the bla _CTX-M-1 -positive isolates had different PFGE profiles, with the exception of four human and pet isolates of lineage ST57 with related PFGE profiles (>80% identity). Three CMY-2-producing isolates were typed as ST58/B1, ST117/D, and ST3632/B2. The IncI1 replicon was detected in all the 33 E. coli studied isolates, in many cases in combination with other replicons: IncF, IncX, IncK, IncR, IncY, colE, or IncN. The bla _CTX-M-1 gene was transferred by conjugation in 22 of the 30 positive strains and was located into IncI1 plasmids (ST3-CC3); the bla _CMY-2 gene was located into a conjugative IncI1 plasmid (ST12) of 97 kb in one strain. One bla _CTX-M-1 -positive strain carried the qnrB19 gene in a 33 kb IncX plasmid. Diverse genetic lineages are detected in extended-spectrum beta-lactamase- and AmpC beta-lactamase-producing E. coli from different origins. The bla _CTX-M-1 and bla _CMY-2 genes were associated with conjugative IncI1 (ST3 and ST12, respectively) plasmids in E. coli strains from human and animal origin.