Antimicrobial-Resistant Bacteria Isolated from Clinical Mastitis Cases

Abstract

Background: Clinical mastitis in dairy cows is a significant concern due to its impact on productivity and milk quality. The emergence of antimicrobial resistance in pathogens causing clinical mastitis complicates treatment strategies.

Objectives: This study aimed to identify bacteria from clinical mastitis cases and investigate their antimicrobial resistance.

Methods: Bacteria were isolated from milk samples of cows with clinical mastitis using standard bacterial culture techniques. Identification was performed through Gram staining and biochemical assays. Antimicrobial susceptibility was tested against seven antimicrobials using the Kirby-Bauer disk diffusion method and interpreted according to Clinical and Laboratory Standards Institute guidelines.

Results: Identified bacteria included Escherichia coli, Staphylococcus aureus, Enterobacter aerogenes, and Pseudomonas sp., among others. All tested isolates exhibited multidrug resistance. E. coli was resistant to all tested antimicrobials, while S. aureus and E. aerogenes were susceptible to gentamicin, tetracycline, and trimethoprim. Pseudomonas sp. was sensitive only to gentamicin.

Conclusion: Multidrug-resistant bacteria were identified in milk samples from clinical mastitis cases, highlighting the importance of antimicrobial stewardship.