Seagulls of the Berlengas Natural Reserve of Portugal as Carriers of Fecal Escherichia coli Harboring CTX-M and TEM Extended-Spectrum Beta-Lactamases

Abstract

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.

Genetic Detection of Extended-Spectrum β-Lactamase-Containing Escherichia coli Isolates from Birds of Prey from Serra da Estrela Natural Reserve in Portugal

“…The ␤-lactamase genes detected in these isolates were as follows: Tyto alba (n ϭ 1), bla SHV-5 plus bla TEM-1b (n ϭ 2), bla SHV-5 (n ϭ 1), and bla TEM-20 (n ϭ 1) ( Table 2). The bla CTX-M-1 gene was found in most of our ESBL-positive E. coli isolates (n ϭ 28); this ESBL was also reported in studies of healthy poultry (13) and by our research group in healthy pets (9) and wild animals (10,17). It is interesting to underline that approximately half of the bla CTX-M-1 -containing E. coli isolates also harbored a variant of a bla TEM gene, concretely bla TEM-1b, bla TEM-1d , or bla TEM-20 .…”

“…Thus, many studies have been done in order to understand the mechanisms of bacterial drug resistance, as many multidrugresistant bacterial strains have been detected in domestic animals and humans (12). Recent studies from our research group have focused on wild animals, trying to understand how they acquire resistance to antibiotics without direct contact (11,17,20). One of the most clinically relevant antimicrobial resistance mechanisms is constituted by extended-spectrum ␤-lactamases (ESBLs) (3,16) harbored by Enterobacteriaceae, such as Escherichia coli, commensals of the gastrointestinal tract of animals and humans, serving as a reservoir for resistances, namely, to ␤-lactam antibiotics (1,15).…”

“…The presence of genes encoding TEM, SHV, OXA, CTX-M, and CMY type ␤-lactamases was studied by specific PCRs (17). All obtained amplicons were sequenced on both strands, and sequences were compared with those included in the GenBank database and at the Lahey Clinic website (http://www.lahey.org /Studies/) to identify the ␤-lactamase genes.…”

“…Non-␤-lactamase genes [tetA/tetB, aadA, aac(3)-II/aac(3)-IV, aac(6Ј), cmlA, and sul1/sul2/sul3, associated with tetracycline, streptomycin, gentamicin, amikacin, chloramphenicol, and trimethoprim-sulfamethoxazole resistance, respectively] were also studied by PCR (17). The presence of the genes intI1 and intI2, encoding class 1 and 2 integrases, respectively, was studied by PCR.…”

Resistance to Broad-Spectrum Antibiotics in Aquatic Systems: Anthropogenic Activities Modulate the Dissemination of bla CTX-M -Like Genes

“…isolates and was found more frequently among isolates from polluted sites. Recently, in several environmental studies, members of the same genera have been identified as ESBL producers, enforcing their relevance and importance for resistance monitoring (14,15,27). We investigated the presence of different ESBL genes and found bla CTX-M genes to be the most prevalent, followed by bla TEM genes.…”