Resistance to antimicrobial agents among enterococci isolated from fecal
samples of wild marine species in the southern coast of Brazil.
Janira Prichula a,b,1, Rebeca Inhoque Pereira a,b,1, Guilherme Raffo Wachholz b, Leonardo Almansa Cardoso a,
Neidimar Cezar Correa Tolfo b, Naiara Aguiar Santestevan a, AlineWeber Medeiros a, Maurício Tavares c,
Jeverson Frazzon d, Pedro Alves d’Azevedo b, Ana Paula Guedes Frazzon a,⁎
a Microbiology, Immunology and Parasitology Department, Federal University of Rio Grande do Sul (UFRGS), Sarmento Leite 500, room 158, 90050-170, Porto Alegre, RS, Brazil
b Gram-positive Coccus Laboratory, Federal University of Health Sciences of Porto Alegre (UFCSPA), Sarmento Leite 245, room 204, 90050-170, Porto Alegre, RS, Brazil
c Center for Coastal Studies, Limnology and Marine (CECLIMAR), Institute of Biosciences, UFRGS. Av. Tramandaí, 976, 95625-000, Imbé, RS, Brazil
d Food Science Institute, UFRGS, Av. Bento Gonçalves 9500 – Campus do Vale – Prédio 443.212, 91501-970, Porto Alegre, RS, Brazil
a r t i c l e i n f o a b s t r a c t
Article history:
Received 1 December 2015
Received in revised form 25 February 2016
Accepted 26 February 2016
Available online 5 March 2016
The purpose of this study was to evaluate species distribution, antimicrobial resistance profiles, and presence of
resistance genes in enterococci isolated from fecal samples of wild marine species, including seabirds (n=12),
sea turtles (n=8), and mammals (n=3) found alive or dead in southern coast of Brazil. Enterococci were classified
based on phenotypic and genotypic characteristics, tested for antibiotic susceptibility, and the presence of
tet(S), tet(M), tet(L), mrsC, and erm(B) genes by PCR. Enterococcus faecalis and Enterococcus faecium were the
most common species. Single (37.09%), double (25.80%), and multiple (16.12%) antibiotic resistance patterns
were observed. Resistance to rifampicin occurred most frequently. The msrC, tet(M), and/or tet(L) genes were detected
in 60.15%, 73.07%, and 23.07% of the resistant strains, respectively. In conclusion, the presence of antibiotic
resistant strains in these species could be related to food web interactions and aquatic pollutants or linked to
environmental resistome.
© 2016 Elsevier Ltd. All rights reserved.
Keywords:
Wild marine species
Enterococci resistant
Resistance genes
1. Introduction
Biological fluids contaminated with antimicrobials or antimicrobialresistant
microorganisms fromhuman and animal origins, such as urine
and feces, are being released into the sewage—particularly aswastewater
fromhospitals and intensive agricultural installations (Baquero et al.,
2008). These effluents provide the pathway for introduction of resistant
bacteria into seawater, thereby contaminating the species inhabiting
these environments (Kummerer, 2009a). The impact created by the
presence of antimicrobial agents in the aquatic environment and the
frequency with which these resistance genes are transferred remains a
subject of debate (Kummerer, 2009b).
Past studies conducted on marine species have discussed drugresistant
bacteria arising from marine environments. Al-Bahry et al.
(2009) isolated antibiotic-resistant bacteria from the eggshell layers, albumen,
and yolk of green turtle (Chelonia mydas) eggs. The study indicates
that green turtle populations were subjected to polluted
effluents during some of their migratory routes and feeding habitats.
Rose et al. (2009) reported widespread antibiotic resistance in marine
vertebrates off the northeastern coast of the United States. Stewart
et al. (2014) isolated antibiotic-resistant bacteria from fecal and blowhole
swabs of wild bottlenose dolphins (Tursiops truncatus).
Enterococci are considered commensal microbiota of the oral cavity,
genitourinary, and gastrointestinal tract of humans and other species
that are widely distributed in nature. This genus has the ability to survive
adverse environmental conditions, including extreme temperatures
(10–45 °C), an extreme range of pH (4.5–10.0), and high salinity
(6.5%) (Teixeira et al., 2011). The species most frequently encountered
in the gastrointestinal tract are Enterococcus faecalis, E. faecium,
E. hirae, E. durans, E. casseliflavus, E. gallinarum, and E. mundtii (Poeta
et al., 2005; Layton et al., 2010; Marinho et al., 2013; Lebreton et al.,
2014). The occurrence of these different species appears to vary according
to the host and its age, diet, underlying diseases, and prior antimicrobial
therapy (Lebreton et al., 2014).
The resistance to several classes of antimicrobial agents is a remarkable
characteristic of enterococcal isolates (Kristich et al., 2014). Many
species are recognized for their capacity to acquire and transfer resistance
and virulence genes, which provides selective advantages for survival
and dispersal in the environment (Gilmore et al., 2013). As a result,
the presence of the enterococci has been investigated andmonitored in
a variety of habitats, providing important information regarding the
Marine Pollution Bulletin 105 (2016) 51–57
⁎ Corresponding author at: Microbiology, Immunology and Parasitology Department,
Federal University of Rio Grande do Sul, Av. Sarmento Leite 500, room 216, 90050-170,
Porto Alegre, RS, Brazil.
E-mail address: ana.frazzon@ufrgs.br (A.P.G. Frazzon).
1 Janira Prichula and Rebeca Inhoque Pereira contributed equally to the work and are
listed alphabetically.
http://dx.doi.org/10.1016/j.marpolbul.2016.02.071
0025-326X/© 2016 Elsevier Ltd. All rights reserved.
Contents lists available at ScienceDirect
Marine Pollution Bulletin
journal homepage: www.elsevier.com/locate/marpolbul
