ABSTRACT
Escherichia coli, an Enterobacterales member, is a normal representative of the microbiota of homeothermic animals. Most strains are commensal, but several pathotypes can cause disease, and numerous antimicrobial resistance factors have been identified. These bacteria have spread rapidly in recent years, highlighting the importance of screening the environment and non-human reservoirs for virulent strains and/or those presenting resistance factors, in addition to other microorganisms of public health importance. In this context, this study aimed to survey Enterobacteriales present in seabirds sampled along the Brazilian coast, comparing findings between migratory and resident birds, as well as between wrecked and non-wrecked animals. Escherichia coli pathotypes were also characterized through rapid seroagglutination and polymerase chain reaction techniques and antimicrobial resistance profiles were investigated through the disc agar diffusion method. Cloacal, ocular, oral, tracheal, and skin lesion swabs, as well as fresh feces, were collected from 122 seabirds. The findings indicate these animals as important hosts for opportunistic human pathogens. Escherichia coli strains were identified in 70 % of the analyzed seabirds, 62 % of which displaying resistant or intermediate profiles to at least one antimicrobial, while 7% were multiresistant. Resistance to tetracycline (22 %), nalidixic acid (15 %), trimethoprim-sulfamethozaxol (14 %) and ampicillin (12 %) were the most prevalent. Resistance to cefoxitin, a critically important antimicrobial for human medicine, was also detected. Virulence genes for one of the EAEC, ETEC or EPEC pathotypes were detected in 30 % of the identified strains, the first two described in seabirds for the first time. The EAEC gene was detected in 25 % of the sampled seabirds, all resident, 8 % of which exhibited a multidrug-resistant profile. Thus, seabirds comprise important reservoirs for this pathotype. Escherichia coli was proven an ubiquitous and well-distributed bacterium, present in all evaluated bird species and sampling sites (except Marajó Island). According to the chi-square test, no significant differences between E. coli prevalences or antimicrobial resistance profiles between migratory and resident and between wrecked and non-wrecked seabirds were observed. Thus, migratory birds do not seem to contribute significantly to E. coli frequencies, pathotypes or antimicrobial resistance rates on the Brazilian coast.
ABSTRACT
In view of growing concerns, in a One Health context, regarding the transport and dissemination of pathogenic microorganisms among seabirds and other vertebrate animals, including humans, the aim of this study was to identify Salmonella spp. in stranded and non-stranded resident and migratory wild seabirds from the Brazilian coast. Antimicrobial susceptibility and molecular profiles, quinolone resistance genes and antigenic characterization of the isolates were also carried out. Fresh faeces and cloacal swabs were obtained totaling 122 seabirds sampled throughout different Brazilian coast regions. At the laboratory, sample culturing, Salmonella spp. isolation and biochemical identification were performed, followed by antigenic profile identification by serum agglutination, susceptibility profile characterization by the agar disc diffusion technique, detection of quinolone resistance genes (qnrA, qnrB, qnrS) using the multiplex polymerase chain reaction technique (multiplex PCR) and, finally, isolates profiles identification by pulsed field gel electrophoresis (PFGE). Salmonella enterica subsp. enterica was identified in 7% of the studied birds, comprising three different serovars: Panama (63 %), Typhimurium (25 %) and Newport (13 %). The most important findings reported herein are the first description of Salmonella panama in seabirds and the totality of isolates being resistant (or intermediate) to at least one tested antimicrobial, with emphasis on quinolone resistance. The molecular results suggest that the observed resistance cannot be explained by the presence of plasmid-mediated quinolone resistance genes. The PFGE suggests that the Panama and Newport profiles detected herein are not yet widespread in Brazil, unlike Typhimurium, which is already well distributed throughout the country. Considering this finding, we suggest that seabirds are an important link in the epidemiological chain of this serovar. The monitoring of these bacteria in seabirds, as well as of their susceptibility profiles to antimicrobials, must be continuous, strengthening the role of these animals as environmental health indicators and sentinels.
