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Published on: December 27, 2010
Comparison of biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis strains isolated from sheep
M Vasil'1, Z Farkasova1, J Elecko1
1Institute of Animal Breeding, Department of Nutrition, Dietetics and Animal Breeding, University of Veterinary Medicine and Pharmacy, Komenskeho 73, 041 84 Kosice, the Slovak Republic.
Abstract:
In this study we investigated 24 strains of Staphylococcus aureus and 33 strains of Staphylococcus epidermidis isolated from milk of sheep with clinical mastitis, for their ability to form biofilms. Three methods for the determination of a biofilm were used. When evaluating the growth on Congo Red agar (CRA), 79.2% S. aureus strains and 72.7% S. epidermidis strains were positive for biofilm formation. The quantitative method of biofilm detection on a Microtitre Plate (MTP) revealed positive results for 75.0% of S. aureus samples and 75.8% for S. epidermidis samples. Using PCR method for determination of the presence of genes that affect formation of biofilms, the most frequently determined genes were eno in both S. aureus (18/24; 75.0%) and S. epidermidis strains (20/33; 60.6%). The genes icaAB and ebpS were detected in both S. aureus and S. epidermidis strains, and similarity between these strains was 12.5% - 15.1% and 4.2% - 6.0%, respectively. The bap was recorded only in S. epidermidis (3.0%). Statistical comparison of the level of biofilm formation was performed using Chi square test. There were no statistically significant differences in the amount of biofilm formation between two methods for detection of biofilm CRA and MTP (p>0.05). Comparison of all six monitored parameters showed no dependence of characteristics of the tested strains S. aureus and S. epidermidis at significance level α = 0.05. Biofilm formation by the bacteria isolated from 57 cases of clinical mastitis in sheep was confirmed. Sensitivity and specificity of the CRA method for S. aureus were 94.44% and 66.66%, respectively, and for S. epidermidis 92.0% and 87.5%, respectively. Both CRA and MTP methods can be recommended for the detection of biofilm production by S. aureus and S. epidermidis strains isolated from milk of sheep with clinical mastitis.
Insights
This study confirmed biofilm formation in Staphylococcus bacteria from sheep mastitis milk. Congo Red Agar and Microtitre Plate methods are reliable for detecting these biofilms.
Area of Science:
- Microbiology
- Veterinary Science
- Bacterial Pathogenesis
Background:
- Bacterial biofilms contribute to persistent infections, posing challenges in clinical settings.
- Staphylococcus aureus and Staphylococcus epidermidis are common mastitis pathogens in sheep.
- Understanding biofilm formation is crucial for developing effective treatment strategies.
Purpose of the Study:
- To investigate biofilm formation in Staphylococcus aureus and Staphylococcus epidermidis strains isolated from sheep with clinical mastitis.
- To compare the efficacy of three different methods for biofilm detection: Congo Red Agar (CRA), Microtitre Plate (MTP), and PCR.
- To identify genes associated with biofilm formation in these bacterial strains.
Main Methods:
- Isolation and identification of Staphylococcus aureus and Staphylococcus epidermidis from milk samples of sheep with clinical mastitis.
- Biofilm detection using Congo Red Agar (CRA) and Microtitre Plate (MTP) assays.
- Polymerase Chain Reaction (PCR) to detect biofilm-related genes (eno, icaAB, ebpS, bap).
Main Results:
- High prevalence of biofilm formation was observed: 79.2% of S. aureus and 72.7% of S. epidermidis on CRA; 75.0% of S. aureus and 75.8% of S. epidermidis on MTP.
- The eno gene was most frequently detected in both species (75.0% S. aureus, 60.6% S. epidermidis).
- No statistically significant differences were found between CRA and MTP methods for biofilm detection (p>0.05).
Conclusions:
- Both Congo Red Agar and Microtitre Plate methods are reliable for detecting biofilm production in Staphylococcus strains from ovine mastitis.
- The study confirms the significant role of biofilm formation in Staphylococcus species causing clinical mastitis in sheep.
- Further research into specific biofilm genes can aid in understanding and combating mastitis infections.
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