Detection of Escherichia Coli and Other Enterobacteriales Members in Seabirds Sampled Along the Brazilian Coast

Abstract

Escherichia coli, an Enterobacterales member, is a normal representative of the microbiota of warm-blooded 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. E. 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. E. 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. E. coli was proven an ubiquitous and well-distributed bacterium, present in all evaluated bird species and sampling sites. 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.

Keywords: Escherichia Coli, Seabirds, Enterobacteriales, Pathotypes, Antimicrobial Resistance, EAEC, ETEC, EPEC