Antimicrobial resistance and virulence profiles of Enterobacterales isolated from two-finger and three-finger sloths (Choloepus hoffmanni and Bradypus variegatus) of Costa Rica

Background

Wildlife has been recently recognized as an environmental reservoir for antimicrobial resistance (AMR). However, less information on this topic is available in animals released back into the wild after rehabilitation in wildlife facilities, compared with studies performed exclusively in captive or free-ranging wildlife. This study aimed to evaluate the potential influence of captivity and/or treatment while in captivity of wild sloths on the AMR and virulence profiles of sloths' Enterobacterales.

Methods

Oral and rectal swab samples were collected from 39 two-finger (Choloepus hoffmanni) and three-finger sloths (Bradypus variegatus) of Costa Rica (n = 78) and analyzed using conventional bacteriological techniques. A generalized linear mixed model was applied to estimate the isolates' multiple antimicrobial resistance and virulence indices as a function of animal status.

Results

A considerable level of resistance was detected, especially for Citrobacter youngae and Escherichia coli, with 17.5% of isolates classified as multidrug-resistant. Virulence indices of isolates from rehabilitated sloths were significantly higher than the ones from sloths being hand-reared for shorter periods.

Conclusions

To our knowledge, this is the first description of sloths' antimicrobial resistant Enterobacterales, suggesting that sloths' rehabilitation and consequent exposure to humans, may promote the selection of bacteria with higher virulence. Ultimately, these bacteria may represent a threat to human and animal health due to their zoonotic potential and AMR and virulence profiles.

RENAL EVALUATION IN CHOLOEPUS SPECIES

Two species of sloths in the family Megalonychidae, Hoffmann's (Choloepus hoffmanni) and Linnaeus's (Choloepus didactylus) two-toed sloths, are commonly held in zoological institutions. Despite frequent published reports of urinary tract disease in these species, reports of diagnostics are mostly limited to descriptions of hematology and serum chemistry. In this study, repeated urinalysis, urinary chemistry, serum chemistry, and radiographs were collected opportunistically from six Hoffmann's and five Linnaeus's sloths. Proteinuria, bacteriuria, low urine specific gravity, and crystalluria were common in the absence of other signs of urinary tract pathology.

EVALUATION OF 25-HYDROXYVITAMIN D IN HOFFMANN'S TWO-TOED SLOTHS (CHOLOEPUS HOFFMANNI) USING DRIED BLOOD SPOTS ANALYZED BY LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY

Although biochemical analytes have typically been measured using serum or whole blood samples, an increasing number of assays are validated for measurement of analytes from dried blood spots (DBS) on filter paper. DBS techniques are minimally invasive, require only a small sample volume, and simplify processing, storage, and shipment of samples. These qualities make DBS-based assays ideal for sampling of wildlife species in both captive and field settings. In this study, a liquid chromatography-tandem mass spectrometry assay was evaluated for measurement of 25-hydroxyvitamin D in sloths. Paired serum and DBS samples were collected from nine healthy captive Hoffmann's two-toed sloths (Choloepus hoffmanni). Statistical analysis using Passing-Bablok regression analysis, Bland-Altman plots, and the Wilcoxon signed-rank tests found good agreement between 25-hydroxyvitamin D3 measurements in serum and DBS samples. Constant and proportional bias were absent. Results from this study support the use of DBS samples for the evaluation of vitamin D status in Hoffmann's two-toed sloths and provide a foundation for further studies to validate this technique.

SEROSURVEY OF SELECTED ARBOVIRAL PATHOGENS IN FREE-RANGING, TWO-TOED SLOTHS (CHOLOEPUS HOFFMANNI) AND THREE-TOED SLOTHS (BRADYPUS VARIEGATUS) IN COSTA RICA, 2005-07

We screened for antibodies to 16 arboviruses in four populations of free-ranging sloths in Costa Rica. Blood samples were taken from 16 Hoffman's two-toed sloths (HTSs; Choloepus hoffmanni ) and 26 brown-throated sloths (BTSs; Bradypus variegatus ) over a 3-yr period. We used serologic assays to detect antibodies against 10 arboviruses previously described in sloths (St. Louis encephalitis [SLEV], Changuinola, Venezuelan equine encephalitis, Ilheus [ILHV], Oropouche, Mayaro, Utinga, Murutucu, Punta Toro, and vesicular stomatitis [VSV] viruses) and six arboviruses not described in sloths (Rio Grande, West Nile [WNV], eastern equine encephalitis, Piry, Munguba, and La Crosse viruses). Overall, 80% of sloths had detectable antibodies to SLEV, 67% had antibodies to ILHV, 32% to Punta Toro virus, 30% to Changuinola virus, 15% to WNV, 14% to VSV, 11% to Venezuelan equine encephalitis virus, and 10% to Rio Grande virus. No samples had detectable antibodies to the remaining eight viruses. We found a significant increase in prevalence of antibody to VSV in HTSs between 2005 and 2007, and for WNV antibody between 2005 and 2006. We found no significant differences in the prevalences of antibodies to the sampled viruses between the two locations. Antibody prevalences were significantly higher in HTSs than in BTSs for SLEV in 2005. Antibody-positive results for ILHV were likely due to cross-reaction with SLEV. The novel finding of antibodies to Rio Grande virus in sloths could be due to cross-reaction with another phlebovirus. These findings might have implications for land management and domestic animal health. Due to the nature of the study, we could not determine whether sloths could represent amplification hosts for these viruses, or whether they were only exposed and could be used as sentinel species. Further studies are needed to fully characterize arboviral exposure in sloths.