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Isolation of Multidrug-Resistant Mycobacterium Avium Subsp. Avium from a Wild Eurasian Otter (Lutra Lutra)
Irena Reil1, Sanja Duvnjak1, Silvio Špičić1
1Croatian Veterinary Institute, Savska Cesta 143, 10000 Zagreb, Croatia.
Abstract:
Mycobacterium avium subsp. avium is pathogenic mainly to birds, although cases of mycobacteriosis caused by these bacteria have also been reported in other animals and humans. Not much is known about the effects of this pathogen on otters. The aim of this study was to report for the first time the isolation of M. avium subsp. avium in wild otter and to describe its multidrug resistance profile. A female otter injured in a car accident was found dead and subjected to postmortem examination. Apart from the trauma changes, no other macroscopic pathological changes were detected. Bacteriologic examination revealed the presence of acid-fast bacilli in the lymph nodes, which were confirmed by molecular methods as M. avium subsp. avium. Antimicrobial susceptibility testing revealed susceptibility to clarithromycin and amikacin, but resistance to linezolid, moxifloxacin, streptomycin, isoniazid, trimethoprim/sulfamethoxazole, ciprofloxacin, doxycycline, and ethionamide. This is unusual for wild species, which generally should not come into contact with antimicrobials, and may suggest that multidrug-resistant MAC strains are circulating between wild and domestic animals. These results emphasise the need for additional epidemiological studies on non-tuberculous mycobacteria in wildlife and their implications for one health.
Insights
This study reports the first isolation of Mycobacterium avium subsp. avium in a wild otter. The pathogen exhibited unusual multidrug resistance, suggesting potential circulation between wildlife and domestic animals.
Area of Science:
- Veterinary Microbiology
- Wildlife Pathology
- Antimicrobial Resistance
Background:
- Mycobacterium avium subsp. avium (MAA) is a known avian pathogen with sporadic reports in other species.
- Limited data exists on MAA infections and their impact on otter populations.
- Understanding MAA in wildlife is crucial for assessing broader ecological and health implications.
Observation:
- Postmortem examination of a deceased wild otter revealed acid-fast bacilli in lymph nodes.
- Molecular methods confirmed the presence of Mycobacterium avium subsp. avium.
- No other significant macroscopic pathological findings were noted besides trauma.
Findings:
- The isolated MAA strain demonstrated resistance to multiple antimicrobials, including isoniazid, ciprofloxacin, and doxycycline.
- Susceptibility was observed only to clarithromycin and amikacin.
- This multidrug resistance profile is atypical for wildlife, which typically lack antimicrobial exposure.
Implications:
- The findings suggest a potential reservoir and circulation of multidrug-resistant MAA strains between wild and domestic animal populations.
- This highlights the need for further epidemiological research on non-tuberculous mycobacteria in wildlife.
- The study underscores the importance of a 'One Health' approach to monitor and manage antimicrobial resistance in diverse ecosystems.
