Risk of zoonoses involving slow-growing non-tuberculous mycobacteria: Survey of antimicrobial resistance among strains from domestic and wild animals

Abstract

Objectives: Non-tuberculous mycobacteria are opportunistic pathogens that cause disease mainly in immunocompromised hosts. The present study assessed the prevalence of antibiotic resistance among such mycobacteria from domestic and wild animals in Croatia sampled during several years within a national surveillance program.

Methods: A total of 44 isolates belonging to nine slow-growing species were genotyped and analyzed for susceptibility to 13 antimicrobials often used to treat non-tuberculous mycobacterial infections in humans.

Results: Most prevalent resistance was to moxifloxacin (77.3%), doxycycline (76.9%), and rifampicin (76.9%), followed by ciprofloxacin (65.4%), trimethoprim-sulfamethoxazole (65.4%), and linezolid (61.4%). Few isolates were resistant to rifabutin (7.7%) or amikacin (6.8%). None of the isolates was resistant to clarithromycin. Nearly all isolates (86.4%) were resistant to multiple antibiotics.

Conclusion: Our findings suggest substantial risk that human populations may experience zoonotic infections with non-tuberculous mycobacteria that will be difficult to treat using the current generation of antibiotics. Future work should clarify how resistance emerges in wild populations of non-tuberculous mycobacteria.

Keywords: Antimicrobials; Minimum inhibitory concentration; Non-tuberculous mycobacteria; Resistance; Slow-growing non-tuberculous mycobacteria; Zoonotic potential.