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Potential of Pm11 antimicrobial peptide against bovine mastitis pathogens
Kwantida Popitool1, Sirirat Wataradee2, Thanaporn Wichai3
1Program in Biotechnology, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok, Thailand.
Objective:
To investigate an alternative treatment for bovine mastitis by using Pm11 antimicrobial peptide.
Sample:
5 bovine mastitis pathogens that were previously isolated from cows affected by either clinical or subclinical mastitis.
Procedures:
The current study introduces Pm11 antimicrobial peptide as an alternative treatment for bovine mastitis. The antibacterial activity of Pm11 was tested against Escherichia coli strain SCM1249, Klebsiella spp strain SCM1282, Staphylococcus aureus strain CM967, Streptococcus agalactiae strain SCM1084, and Streptococcus uberis strain SCM1310 using minimum bactericidal concentrations (MBCs) and time-kill kinetics. The pathogens' morphological changes were demonstrated using a scanning electron microscope (SEM). The cytotoxicity of Pm11 was assessed using the minimum hemolytic concentration assay.
Results:
MBCs ranged from 2.5 to 10 μM and IC50 ranged from 0.32 to 2.07 μM. Time-kill kinetics at MBC demonstrated that Pm11 reduced viable cell counts of S agalactiae strain SCM1084 and S uberis strain SCM1310 from 105 to 0 CFU/mL within 1 h. E coli strain SCM1249 and S aureus strain CM967 were reduced from 105 to 0 CFU/mL within 4 h. The average Pm11-induced hemolytic activity was < 10% for all Pm11 concentrations tested except at the maximum concentration tested (160 μM: 10.19 ± 2.29%). Based on SEM, Pm11 induced morphological and cellular changes in S aureus and E coli.
Clinical Relevance:
Pm11 antimicrobial peptide demonstrated in vitro antibacterial activity against the common bovine mastitis pathogens E coli, S aureus, S agalactiae, and S uberis, except Klebsiella spp, and should be further investigated in vivo.
Insights
The antimicrobial peptide Pm11 shows promise in treating bovine mastitis, effectively killing common pathogens like E. coli and S. aureus in lab tests. Further in vivo studies are recommended for this alternative bovine mastitis treatment.
Area of Science:
- Veterinary Microbiology
- Antimicrobial Peptides
- Bovine Diseases
Background:
- Bovine mastitis is a significant economic and animal welfare concern in dairy farming.
- Current treatments face challenges with antibiotic resistance and residue concerns.
- Novel therapeutic strategies are needed to combat bovine mastitis effectively.
Purpose of the Study:
- To evaluate the efficacy of Pm11 antimicrobial peptide as a potential alternative treatment for bovine mastitis.
- To determine the antibacterial activity and cytotoxicity of Pm11 against key bovine mastitis pathogens.
Main Methods:
- The study tested Pm11 against five common bovine mastitis pathogens: Escherichia coli, Klebsiella spp., Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus uberis.
- Minimum bactericidal concentrations (MBCs) and time-kill kinetics were employed to assess antibacterial activity.
- Scanning electron microscopy (SEM) was used to visualize pathogen morphological changes, and cytotoxicity was evaluated via hemolytic assays.
Main Results:
- Pm11 exhibited minimum bactericidal concentrations (MBCs) ranging from 2.5 to 10 μM.
- Rapid killing of Streptococcus agalactiae and Streptococcus uberis was observed within 1 hour at MBCs.
- Escherichia coli and Staphylococcus aureus showed significant reduction in viable counts within 4 hours.
- Pm11 demonstrated low hemolytic activity (<10%) across tested concentrations, indicating good safety profile.
- SEM analysis confirmed Pm11-induced morphological damage in Staphylococcus aureus and Escherichia coli.
Conclusions:
- Pm11 antimicrobial peptide possesses in vitro antibacterial activity against major bovine mastitis pathogens, including E. coli, S. aureus, S. agalactiae, and S. uberis.
- The peptide was effective against all tested pathogens except Klebsiella spp.
- These findings support further in vivo investigation of Pm11 as a novel therapeutic agent for bovine mastitis.
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