Human-Associated Methicillin-Resistant Staphylococcus aureus Clonal Complex 80 Isolated from Cattle and Aquatic...

Area of Science:

• Veterinary Microbiology
• Environmental Science
• Public Health

Background:

• Human-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) is primarily documented in South African pig and chicken farms.
• Limited data exists on the prevalence of antibiotic-resistant genes (ARGs), virulence factors (VFs), and multilocus sequence types (MLSTs) of HA-MRSA in cattle farms.
• This study investigated livestock-associated MRSA (LA-MRSA) and its environmental dissemination from cattle farms.

Purpose of the Study:

• To characterize LA-MRSA in cattle farm environments.
• To determine the prevalence of ARGs and VFs in LA-MRSA isolates.
• To investigate the potential spread of LA-MRSA from cattle farms into the surrounding environment, including water bodies.

Main Methods:

• Samples including husbandry soil (HS), nearby river water (NRW), animal manure (AM), and animal drinking water (ADW) were collected from a cattle farm.
• Presumptive MRSA isolates were identified using CHROMagar media.
• Polymerase chain reaction (PCR) was employed for genotyping MRSA sequence types (STs), selected ARGs, and VFs. An MLST-based dendrogram was constructed to analyze strain relatedness.

Main Results:

• MRSA prevalence was highest in HS (30.61%) and ADW (28.57%), followed by NRW (22.44%) and AM (10.20%).
• HS isolates showed the highest prevalence of ARGs, including 100% for mecA, 91.66% for ermA, and 58.33% for blaZ. No ermC or tetM genes were detected.
• Six STs (ST80, ST728, ST1931, ST2030, ST3247, ST5440), all belonging to clonal complex 80 (CC80), were identified. Enterotoxins sec and seq were present in all isolates. The dendrogram showed four clades of MRSA isolates from environmental matrices, including NRW.

Conclusions:

• Livestock environmental matrices, such as soil and water, may serve as reservoirs for MRSA.
• MRSA can disseminate from cattle farms into water resources via runoff.
• Continuous surveillance of HA-MRSA in livestock environments is crucial for public health protection.