Related Experiment Videos
Characteristics of coagulase-negative Staphylococci isolated from bovine intramammary infections
D A Todhunter1, L L Cantwell, K L Smith
1Ohio Agricultural Research and Development Center/Ohio State University, Department of Dairy Science, Wooster 44691.
Abstract:
Coagulase-negative Staphylococci (CNS) isolated from 86 different bovine intramammary infections (IMI) were investigated for their plasmid content, antimicrobial resistance, and infection characteristics. Plasmids were isolated from 30.2% of CNS. Number of plasmid bands ranged from 1 to 5. With the exception of tetracycline resistance, the presence of plasmids was not related to antibiotic resistance. Staphylococcus chromogenes was the CNS most frequently isolated from bovine IMI. Intramammary infections were of long duration (mean = 222 days) and resulted in a low incidence of clinical mastitis (8.1% of IMI). The greatest percentage of IMI (55%) were detected in heifers with 57% of these IMI first detected at calving. A total of 56% of IMI originated during the dry period in second lactation or older cows. The number of plasmid-positive CNS IMI was greater (P < 0.05) in multilactational cows when compared to heifers. The presence of a plasmid-positive CNS had no influence on duration of IMI, origin of IMI, clinical status of the infection, and elimination of IMI.
Insights
Coagulase-negative Staphylococci (CNS) in bovine intramammary infections (IMI) showed plasmid presence unrelated to most antibiotic resistance. Plasmid-positive CNS were more common in older cows but did not affect infection duration or outcome.
Area of Science:
- Veterinary Microbiology
- Bovine Health
- Antimicrobial Resistance
Background:
- Coagulase-negative Staphylococci (CNS) are significant pathogens causing bovine intramammary infections (IMI).
- Understanding the role of plasmids in CNS pathogenicity and antimicrobial resistance is crucial for managing bovine mastitis.
Purpose of the Study:
- To investigate the plasmid content, antimicrobial resistance patterns, and infection characteristics of CNS isolated from bovine IMI.
- To determine the relationship between plasmid presence and antibiotic resistance in CNS.
- To analyze factors influencing IMI duration, origin, and clinical presentation.
Main Methods:
- Isolation and characterization of CNS from 86 bovine IMI cases.
- Plasmid DNA isolation and analysis.
- Antimicrobial resistance profiling.
- Epidemiological analysis of infection characteristics (duration, origin, clinical status).
Main Results:
- Plasmids were detected in 30.2% of CNS isolates, with 1 to 5 plasmid bands observed.
- Plasmid presence was generally not associated with antibiotic resistance, except for tetracycline resistance.
- Staphylococcus chromogenes was the most frequently isolated CNS species.
- IMI were characterized by long duration (mean 222 days) and low clinical mastitis incidence (8.1%).
- 55% of IMI were detected in heifers, often first identified at calving.
- 56% of IMI originated during the dry period in older cows.
- Plasmid-positive CNS were more prevalent in multilactational cows than heifers (P < 0.05).
- Plasmid presence did not influence IMI duration, origin, clinical status, or elimination.
Conclusions:
- Plasmid carriage in CNS from bovine IMI is common but not strongly linked to most tested antimicrobial resistances.
- The presence of plasmids in CNS does not appear to impact the clinical course or resolution of intramammary infections in dairy cows.
- Further research may be needed to elucidate the specific roles of plasmids in CNS pathogenesis in the bovine udder.