Molecular ecology of highest priority critically important antibiotic resistant Escherichia coli from mammals housed at an urban zoo.

OBJECTIVES: Zoos are environments where species of highly valued animals are kept largely separated from others and the wider world. We report the molecular ecology of critically important antibiotic resistant (ABR) Escherichia coli carried by 28 mammalian species housed in a zoo located in an urban residential district. METHODS: Over 3 months we collected 167 faecal samples from captive mammals and processed for E. coli resistant to third-generation cephalosporins (3GC-R) and fluoroquinolones (FQ-R). Isolates were sequenced using Illumina. RESULTS: We identified high rates of faecal sample-level positivity, with 50%, 57% and 36% of mammalian species excreting 3GC-R, FQ-R or dual 3GC-R/FQ-R E. coli, respectively. Isolates represented multiple ST and ABR mechanisms; CTX-M-15 and CMY-2 dominated for 3GC-R, and target-site mutation caused 75% of FQ-R. We identified multiple examples of ABR E. coli transmission between mammalian species in separate enclosures, and a variant of the epidemic plasmid pCT within the zoo. There was no evidence for ABR E. coli leaving the zoo, based on comparative analysis with E. coli from humans, cattle and dogs isolated from the 50 × 50 km region in which the zoo is located. Amoxicillin/clavulanate was the most widely used antibiotic in the zoo, and we identified four widely disseminated amoxicillin/clavulanate resistance mechanisms, including a previously unreported inhibitor-resistant TEM, and the carbapenemase OXA-181. CONCLUSIONS: We conclude that the zoo studied here is a 'melting pot' for the selection and circulation of 3GC-R and FQ-R E. coli, but these circulating E. coli appear captive within the zoo.

Diagnosis and treatment of concurrent dermal malignant melanoma and melanocytomas in a pygmy hippopotamus (Choeropsis liberiensis).

BACKGROUND: Dermal melanocytic neoplasms are common in some even-toed ungulates (Artiodactyla), yet this entity has not been reported in the pygmy hippopotamus to date. Concurrent occurrence of multiple benign and malignant melanocytic neoplasms is unusual. Malignant transformation occurs in a small percentage of benign melanocytic tumours in people but this phenomenon has not been well documented in animals. OBJECTIVES: To report the diagnosis and treatment of concurrent dermal melanocytomas and malignant melanomas in a pygmy hippopotamus. ANIMALS: A 36-year-old intact male pygmy hippopotamus, part of a zoological collection, housed with a 10-year-old female of the same species, presented with multiple raised and pigmented skin masses. METHODS: Initial impression smears of one ulcerated lesion were consistent with inflammation; subsequent histopathological findings from a skin biopsy revealed an underlying malignant melanoma. The animal was anaesthetised, ultrasonographic imaging of the local lymph nodes indicated no local involvement and all skin lesions were removed. Recovery from anaesthesia was unremarkable, skin healing was within normal limits for the species. There was no sign of recurrence 34 months post-surgery. RESULTS: A diagnosis of malignant melanomas and concurrent melanocytomas was made on histopathological evaluation. CONCLUSION AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first reported case of melanocytic neoplasia in the pygmy hippopotamus. The occurrence of both benign and malignant melanocytic skin tumours should be considered in this species.