Death Associated to Methicillin Resistant Staphylococcus aureus ST8 Infection in Two Dolphins Maintained Under Human...

Area of Science:

• Veterinary Microbiology
• Marine Mammal Health
• Zoonotic Diseases

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen in both human and animal health.
• The presence of MRSA in marine mammals is an emerging concern due to potential transmission routes and public health implications.
• Previous reports of MRSA in marine mammals have identified different strains than the one described in this study.

Purpose of the Study:

• To isolate and characterize Methicillin-resistant Staphylococcus aureus (MRSA) from the respiratory tracts of two dolphins of different origins.
• To determine the microbiological and genetic profile of the isolated MRSA strain.
• To investigate potential transmission routes and zoonotic implications of the identified MRSA strain in dolphins.

Main Methods:

• Isolation and identification of Staphylococcus aureus from dolphin respiratory samples.
• Antimicrobial susceptibility testing to confirm methicillin resistance.
• Molecular typing, including whole-genome sequencing or MLST, to determine the clone-complex, sequence type (ST), and spa-type.
• Pathological examination of affected tissues.

Main Results:

• MRSA was successfully isolated from the respiratory tracts of two dolphins: a stranded Risso's dolphin (Grampus griseus) and a common bottlenose dolphin (Tursiops truncatus) calf.
• Genetic analysis confirmed the presence of MRSA clone-complex 8, sequence type (ST) 8, and spa-type t008 in both isolates.
• This specific MRSA strain (ST 8) has not been previously reported in dolphins but is found in human patients.
• Pathological lesions in the bottlenose dolphin calf suggest vertical transmission as a likely route of infection.

Conclusions:

• The study identified a novel MRSA strain (ST 8) in two dolphins, highlighting the potential for MRSA to colonize and infect marine mammals.
• The genetic similarity to strains found in human patients raises concerns about zoonotic potential and interspecies transmission.
• Strict adherence to animal management and hygiene protocols is crucial to mitigate the spread of opportunistic and antibiotic-resistant pathogens like MRSA in captive and wild marine mammal populations.