Escherichia coli isolates containing the following extended-spectrum beta-lactamases have been detected in 11 of 57 fecal samples (19.3%) in Berlengas Island seagulls: TEM-52 (eight isolates), CTX-M-1 (one isolate), CTX-M-14a (one isolate), and CTX-M-32 (one isolate). Most of the extended-spectrum beta-lactamase-positive isolates harbored class 1 or class 2 integrons, which included different antibiotic resistance gene cassettes.

Seventy-six faecal samples were obtained from broilers at slaughterhouse level in Portugal. Samples were inoculated on cefotaxime-supplemented Levine agar plates. Cefotaxime-resistant Escherichia coli isolates were recovered from 32 samples (42.1%), obtaining a total of 34 E. coli isolates (one or two isolates per sample). Susceptibility to 16 antibiotics was studied by disk diffusion method, and 85% of the isolates presented a phenotype of multi-resistance that included antimicrobial agents of at least four different families. Extended-spectrum-beta-lactamases (ESBL) of the TEM and CTX-M groups were detected in 31 ESBL-positive E. coli isolates. Twenty-six isolates harboured the bla(TEM-52) gene and two of them also harboured bla(TEM-1b). The bla(CTX-M-14) gene was identified in three isolates (in association with bla(TEM-1b) in one of them), and bla(CTX-M-32) was demonstrated in two additional isolates. Three of the 34 cefotaxime-resistant isolates (9%) did not produce ESBLs, and two of them presented mutations at positions -42 (C-->T), -18 (G-->A), -1 (C-->T), and +58(C-->T) of the promoter/attenuator region of ampC gene. tet(A) and/or tet(B) genes were detected in all 34 tetracycline-resistant isolates, aadA in all 26 streptomycin-resistant isolates; cmlA in 3 of 6 chloramphenicol-resistant isolates, and aac(3)-II or aac(3)-I + aac(3)-IV genes in all 4 gentamicin-resistant isolates. Different combinations of sul1, sul2 and sul3 genes were demonstrated among the 22 trimethoprim-sulfamethoxazole-resistant isolates. Amino acid changes in GyrA and ParC proteins were identified in all 18 ciprofloxacin-resistant isolates. The results of this study indicate that the intestinal tract of healthy poultry is a reservoir of ESBL-positive E. coli isolates.

A high prevalence of integrons was detected in faecal E. coli of healthy humans. Individuals in the community could be a reservoir of integron-containing E. coli isolates.

A total of 174 E. coli isolates collected from healthy poultry, bovine and ovine recovered between December 2009 and June 2013 in different geographic location in Tunisia, were assessed and examinated for resistance to antimicrobial agents. Avian isolates showed the highest rates of antibiotic resistance: tetracycline (74.7 %), trimethoprim/sulfamethoxazole and amoxicillin with the same rate of resistance (57 %). Prevalences of resistance to the same four antimicrobials in bovine isolates were 33.3 %, 65 %, 30 %, 28.3 %, respectively. However, for ovine isolates, low resistance rates were observed, except for tetracycline (40 %) and amoxicillin (22.85 %). Only one ESBL-producing isolate from chicken was detected. In addition, seventy-seven (44.2 %) isolates were resistant to three or more classes of antibiotics and were considered multidrug resistant (MDR). Interestingly, avian E. coli isolates were more resistant than bovine and ovine ones. These results provide novel insights into the epidemiological characteristics of poultry, bovine and ovine E.coli isolates in Tunisia, and suggest the need for the prudent use of antimicrobial agents in husbandry and the urgent need to establish a national antibiotic resistance monitoring program.

Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli isolates were detected in seven of 105 faecal samples from healthy humans, from two Spanish cities, during 2007. In these isolates, five ESBLs were detected, CTX-M-14 (n = 2), CTX-M-1 (n = 2), CTX-M-32 (n = 1), CTX-M-8 (n = 1) and TEM-52 (n = 1). Both bla(CTX-M-14a) (surrounded by ISEcp1-IS903) and bla(CTX-M-14b) variants (included in an integron structure) were identified in this study. This is the first time that the bla(CTX-M-8) gene and ESBLs of the CTX-M-8 group have been found in Europe and Spain, respectively. Faecal E. coli of healthy humans therefore constitute a reservoir of bla(CTX-M) genes with different surrounding genetic elements.