Vol. 9, Special Issue 2 (2024)

Mastitis is caused by bacteria acquired from the environment and is more predominant in milk yielding cows. Although generally self-limiting, bovine mastitis is a condition with multiple etiologies. Coliform mastitis is caused by Escherichia coli which are the common inhabitants of the gastrointestinal tract. E coli infection of the udder is due to faecal contamination and indicated poor hygiene and maintenance of dairy cattle. In general, treatment of mastitis involves identification of bacteria and their sensitivity to commonly used panels of antibiotics. Antibiotic therapy leads to rapid resolution of symptoms but longer duration of treatment is often practiced to prevent recurrence. Such routine use of antibiotics in dairy cattle selects for resistant bacteria. Antimicrobial peptides (AMPs) are increasingly viewed as potential alternatives to conventional antibiotics and are less prone to elicit resistance in pathogens. In this study a synthetic AMP, Cecropin A (CecA) is shown to be effective against mammary pathogenic Escherichia coli (MPEC) that are isolated from udder infections. The antibacterial activity of the CecA was demonstrated with a minimum inhibitory concentration (MIC) of 75 ug/ ml. The CecA was also shown to be non-haemolytic and non-cytotoxic at the MIC. Our results demonstrate the potential of this CecA peptide for therapeutic use against extended spectrum - multidrug resistant Escherichia coli.