Antibiotic resistance in wildlife from Antarctic Peninsula.

Although considered one of the most pristine ecosystems, Antarctica has been largely influenced by human activities during the last 50 years, affecting its unique biodiversity. One of the major global threats to health is the emergence of antibiotic-resistant bacteria that may be actively transferred to wildlife. We cultured and tested for antibiotic resistance in 137 cloacal and fresh fecal samples of several avian and marine mammal species from the Antarctic Peninsula, the most impacted area in Antarctica. Alarmingly, 80 % of the isolates showed antibiotic resistance, either phenotypically or genotypically. Most of the resistant bacteria, such as Enterobacteriaceae and Enterococcus species, are part of local gastrointestinal microbiota. Penguins and pinnipeds harbored a great diversity of antibiotic resistance and must be eligible as sentinels for future studies. These results show that antibiotic resistance has rapidly transferred to bacteria in Antarctic wildlife, which is a global matter of concern.

I've got you under my skin: inflammatory response to elephant seal's lice.

Seals (Phocidae) undergo an annual cycle of moulting that implies hair regeneration, and in the case of southern elephant seals, it also involves the superficial strata of the epidermis. Therefore, surviving the moulting period is crucial for their obligate and permanent ectoparasites. Throughout evolutionary time, sucking lice (Echinophtiriidae) have developed morphological, behavioural and ecological adaptations to cope with the amphibious lifestyle of their hosts. Lepidophthirus macrorhini, the Southern elephant seal louse species, faces the additional challenge of surviving attached to the host during the moulting period. Since lice live on the skin, L. macrorhini has developed a unique survival strategy by piercing the skin of their host, thus keeping them protected from moulting. During fieldwork in Patagonia and Antarctica, skin samples with lice within were collected for histological analysis to assess whether these parasites caused damage to the host. Lice generate an inflammatory process in the host's dermis, and these lesions could alter the normal chemical and mechanical protective properties of the skin facilitating secondary infections. Further studies that analyse the potential pathogens in those skin lesions are necessary to properly assess the real impact of ectoparasites on their host health.

Serological screening for Brucella spp. and Leptospira spp. antibodies in southern elephant seals Mirounga leonina from Elephant Island, Antarctica, in 2003 and 2004.

Brucella spp. and Leptospira spp. antibodies were surveyed in 35 southern elephant seals (SESs) Mirounga leonina at Elephant Island (South Shetland Islands), western Antarctic peninsula, in the Austral summer of 2003 and 2004. The rose Bengal test and a commercial competitive ELISA (c-ELISA) were used to detect Brucella spp. exposure, and the microscopic agglutination test (MAT) with 22 live serovars was used to determine anti-Leptospira spp. antibodies. We found evidence of Brucella spp. exposure in 3 of 35 (8.6%) SESs tested via the c-ELISA displaying high percentage inhibition (PI), similar to other studies in pinnipeds in which Brucella spp. antibodies have been determined. Two of the 3 positives were pups (PI = 70.4 and 86.6%), while the third was an adult female (PI = 48.8%). The 3 c-ELISA positive SESs were additionally tested via the serum agglutination test but were found to be negative. All individuals were negative for antibodies against 22 Leptospira spp. serovars by MAT. These results contribute to the knowledge and monitoring of zoonotic pathogens with epizootic potential in Southern Ocean pinnipeds. Given the potential impact that pathogens may have on the abundance of wild (sometimes threatened and endangered) populations, constant monitoring and surveillance are required to prevent pathogen spread, particularly under forecast climate change scenarios.

So happy together: juvenile crabeater seal behavior improves lice transmission.

Lice from family Echinophthiriidae are of the few insects that have successfully colonized marine environment living as ectoparasites of pinnipeds, i.e., sea lions, seals, and the walrus. They have developed unique adaptations to cope with the amphibious lifestyle of their hosts. Because eggs do not survive underwater, lice could only reproduce when their host remains on pack ice enough time. Consequently, lice generations per year are limited by host haul-out behavior. The objective of this work is to study the effect of host sex and age class, and the annual variation on the prevalence and mean abundance of Antarctophthirus lobodontis in crabeater seals from the Antarctic Peninsula. During three consecutive field-seasons, we collected lice from 41 crabeater seals (23 females, 16 males, 2 indeterminate, being 24 adults, and 17 juveniles). We investigated this effect on the prevalence and mean abundance by a generalized linear model formulation in a Bayesian framework. According to the lowest Deviance Index Criterion model, sex host does not affect prevalence nor mean abundance. We found that juveniles present greater abundance and prevalence than adults, possibly due to foraging habits. They spent more time on the ice than adults in groups of dozens of animals. This behavior would favor both egg development and lice transmission. We do not find adult females with lice, which suggests that transmission of A. lobodontis should be horizontal. The high mean abundance of lice in 2014 could be associated with an unusual increase in Lobodon carcinophaga population, probably related to the pack-ice availability and zooplankton abundance.

Isotopic variation in blood components based on their biochemistry and physiology: A comparison between sharks and fur seals.

Research using stable isotopes analysis (SIA) of carbon (δ13 C) and nitrogen (δ15 N) in blood components is lacking, because of the challenge of sample collection, processing, and storage in remote areas. There also is a paucity of information regarding the effect of tissue biochemical composition on isotopic ratios with few comparisons among taxa. We collected blood samples from shortfin mako sharks (n = 70; 2016) and Guadalupe fur seals (n = 25; 2017). All samples were centrifuged to obtain plasma from sharks and serum from the Guadalupe fur seals, and all the samples were prepared for SIA and analyzed using a Costech 4010 elemental analyzer interfaced with a Delta V Plus isotope ratio mass spectrometer. We found significant differences between plasma δ13 C values of shortfin mako sharks (-17.6 ± 0.9‰) and serum of Guadalupe fur seals (-20.3 ± 1.2‰), but we did not find any differences for δ15 N values between the two species. The differences in δ13 C values between species are probably due to the specific blood composition and to the different biochemical characteristics and different adaptations within taxa. These findings highlight the importance of further research on the influence of biochemistry features on isotopic results, in this way a more accurate assessment will be possible for this factor, separating it from the dietary influences on stable isotopic values.

Reproductive Tract Histology in South American Fur Seal Pups (Arctophoca australis).

In the present study, a detailed histological description of the female reproductive tract of South American fur seal (Arctophoca australis) pups has been conducted. The uterine tube was covered by cuboidal to columnar epithelium; nerve fibers were present in the mesosalpinx and beneath the muscular layer. The uterus was bipartitus; the endometrial surface of the horns was lined by a simple cuboidal or columnar epithelium with deep tubular glands; caudally ("the transition area"), the epithelium changed to pseudostratified columnar, few tubular glands were present and the myometrium increased in width. A bistratified epithelium internally coated the uterine body, whereas it changed to cylindrical stratified epithelium with a highly vascularized lamina propria and a strong muscular layer in the cervix; no endometrial glands were observed in this region. From the transition area of the uterus to the vagina there were several nerve fibers and ganglia belonging to the uterovaginalis plexus. In the vestibule, hymenal folds were poorly developed; adnexa structures included the major vestibular glands and a neurovascular structure similar to the vestibular bulb. Minor vestibular glands were associated with the clitoris. The skin of the perineum was lined by a keratinized stratified epithelium, pigmented, with sebaceous glands, sweat glands and hair follicles. This is the first detailed histological description of the reproductive tract of South American fur seal pups, including the glandular adnexa and nerve structures. These results contribute to the reproductive biology in Pinniped species, and give a better understanding of the utero-placental perfusion mechanism during diving. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:600-613, 2017. © 2016 Wiley Periodicals, Inc.

Holocene changes in the trophic ecology of an apex marine predator in the South Atlantic Ocean.

Predators may modify their diets as a result of both anthropogenic and natural environmental changes. Stable isotope ratios of nitrogen and carbon in bone collagen have been used to reconstruct the foraging ecology of South American fur seals (Arctocephalus australis) in the southwestern South Atlantic Ocean since the Middle Holocene, a region inhabited by hunter-gatherers by millennia and modified by two centuries of whaling, sealing and fishing. Results suggest that the isotopic niche of fur seals from Patagonia has not changed over the last two millennia (average for the period: δ13C2200-0BP = -13.4 ± 0.5‰, δ15N2200-0BP = 20.6 ± 1.1‰). Conversely, Middle Holocene fur seals fed more pelagically than their modern conspecifics in the Río de la Plata region (δ13C7000BP = -15.9 ± 0.6‰ vs. δ13CPRESENT = -13.5 ± 0.8‰) and Tierra del Fuego (δ13C6400-4300BP = -15.4 ± 0.5‰ vs. δ13CPRESENT = -13.2 ± 0.7‰). In the latter region, Middle Holocene fur seals also fed at a higher trophic level than their modern counterparts (δ15N6400-4300BP = 20.5 ± 0.5‰ vs. δ15NPRESENT = 19.0 ± 1.6‰). Nevertheless, a major dietary shift was observed in fur seals from Tierra del Fuego during the nineteenth century (δ13C100BP = -17.2 ± 0.3‰, δ15N100BP = 18.6 ± 0.7‰), when marine primary productivity plummeted and the fur seal population was decimated by sealing. Disentangling the relative roles of natural and anthropogenic factors in explaining this dietary shift is difficult, but certainly the trophic position of fur seals has changed through the Holocene in some South Atlantic regions.

Characterization of the faecal bacterial community of wild young South American (Arctocephalus australis) and Subantarctic fur seals (Arctocephalus tropicalis).

The microbiota of wild marine mammals is poorly understood, perhaps due to the migratory habits of some species and the difficulty in obtaining samples. Using high-throughput sequencing, the present study examines the faecal bacterial community of wild young South American (Arctocephalus australis) and Subantarctic fur seals (A. tropicalis). Faecal samples from South American (n = 6) and Subantarctic fur seals (n = 4) found dead along the south coast of Brazil were collected. Sequences were assigned to taxa using the Ribosomal Database Project-Bayesian classifier. Diversity of the microbiota was assessed by categorization of sequence reads into operational taxonomic units. Results indicate that Firmicutes (88.556%-84.016%) was the predominant phylum in South American and Subantarctic fur seals. The distribution of Actinobacteria and Proteobacteria varied according to the fur seal species. Fusobacteria and Bacteroidetes represented less than 1% of the sequences. The most abundant order in both fur seals was Clostridiales (88.64% and 87.49%). Individual variable incidences were observed in the composition of family among the fur seals, though the families Lachnospiraceae, Peptostreptococcaceae, Ruminococcaceae and Coriobacteriaceae were more prevalent. This study provides insight into the faecal bacterial community of wild young South American and Subantarctic fur seals.

Antimicrobial resistance and virulence factor gene profiles of Enterococcus spp. isolates from wild Arctocephalus australis (South American fur seal) and Arctocephalus tropicalis (Subantarctic fur seal).

Enterococci are natural inhabitants of the gastrointestinal tracts in humans and animals. Epidemiological data suggest that enterococci are important reservoirs of antimicrobial resistant genes that may be transmitted from other bacterial species The aim of this study was to investigate the species composition, antimicrobial resistance and virulence genes in enterococci recovered from fecal samples of wild Arctocephalus australis and A. tropicalis found dead along the South Coast of Brazil. From a total of 43 wild fur seals, eleven were selected for this study. Phenotypic and genotypic characterizations were used to classify Enterococcus species. Strains were tested for susceptibility to 10 antibiotics, presence of ace, gelE, asa, cylA, tet(L), tet(M) and erm(B) genes by PCR, and genetic variability using RAPD-PCR. Among the 50 enterococci isolated, 40% were Enterococcus faecalis, 40% E. hirae, 12% E. casseliflavus and 8 % other enterococcal species. Resistance profiles were observed to erythromycin, nitrofurantoin, tetracycline, norfloxacin and ciprofloxacin. The prevalence of virulence genes was ace (68%), gelE (54%), asa (22%) and cylA (4%). In erythromycin- and tetracycline strains, erm(B) and tet(M) were detected, respectively. The RAPD-PCR demonstrated a close phylogenetic relationship between the enterococci isolated from A. australis and A. tropicalis. In conclusion, different enterococcus species showing antimicrobial resistance and virulence determinates were isolated from fecal samples of fur seals. Antibiotic resistant strains in these animals could be related within food chain and aquatic pollutants or linked to environmental resistome, and demonstrates the potential importance of these animals as reservoirs and disseminators of such determinants in marine environmental.

Ovarian follicular morphometry of South American fur seal pups (Arctophoca australis).

The aim of this study was to analyze the morphometric characteristics of ovarian follicles and their distribution in the ovarian cortex in South American fur seal pups (Arctophoca australis). Samples were obtained from animals stranded in the Uruguayan Atlantic coast. Ovaries were dissected, fixed, weighed, and processed by standard histological techniques. Ovarian weight increased with pup age and body length. There was an increase in the diameter of the oocytes (22.24 ± 0.6 to 68.2 ± 5.3 µm), the nuclei (10.04 ± 0.2 to 20.7 ± 1.6 µm), and follicles (30.4 ± 1.2 to 252.6 ± 53.6 µm) of type 1 to type 5 follicles; there was a wide range of variation in the diameter of follicle type 4 and 5. Granulosa layer thickness increased between follicles type 3 and 4, whereas between type 4 and 5 there was a reduction. Thecal layer from follicles type 3 and 4 consisted of 1-2 layers of cells, whereas type 5 showed an increase in thickness (3.13 ± 0.3 to 13.8 ± 5.2 µm). Follicles type 1 and 2 occupied superficial regions within the ovarian cortex while the remaining follicles had a deeper location. These results provide a basis for comparison with females of other age categories as well as follicular dynamics studies in South American fur seals.