Study tests donkey milk against drug-resistant Gram-negative isolates
Bottom line
A new study in Animals tested whether raw and pasteurized donkey milk could slow the growth of 10 clinically relevant Gram-negative Enterobacterales isolates, including strains producing CTX-M, OXA-48, KPC, NDM, and VIM resistance enzymes. The paper adds to a growing body of work suggesting donkey milk has intrinsic antimicrobial activity tied to bioactive components such as lysozyme and lactoferrin, and it specifically pushes that question into the antimicrobial resistance space by looking at multidrug-resistant clinical isolates rather than only foodborne or laboratory strains. Earlier donkey milk research has shown antibacterial effects can persist after pasteurization, with lysozyme activity often largely preserved under standard heat treatment. (mdpi.com)
Why it matters: For veterinary professionals, this is more of a signal than a practice-changing result. AMR remains a major One Health concern, and Gram-negative resistant pathogens continue to rank among WHO’s highest-priority bacterial threats. Findings like these may help guide future work on milk-derived antimicrobials, adjunct therapies, or functional feed and food ingredients, but this study is in vitro and doesn’t support clinical use of donkey milk as a treatment. It also sits alongside a separate safety reality: raw donkey milk still requires pasteurization for commercial use, and prior reviews have emphasized microbiological hazards associated with raw consumption. (who.int)
What to watch: Watch for follow-up studies that identify which milk fractions drive the effect, compare raw versus pasteurized activity head-to-head, and test whether any in vitro findings translate into clinically relevant veterinary or translational applications. (mdpi.com)
Key facts
- Study
- In vitro study in Animals
- Question
- Whether raw and pasteurized donkey milk can inhibit clinically relevant Gram-negative Enterobacterales
- Sample
- 10 clinical isolates
- Resistance markers
- CTX-M, OXA-48, KPC, NDM, and VIM
- Organism group
- Gram-negative Enterobacterales
- Main takeaway
- The study adds to evidence that donkey milk has intrinsic antimicrobial activity
- Proposed contributors
- Lysozyme and lactoferrin
- Limitation
- In vitro only, so it does not support clinical use of donkey milk as treatment
A newly published study in Animals examines whether raw and pasteurized donkey milk can inhibit the growth of clinically relevant Gram-negative bacteria with different antimicrobial resistance profiles, including carbapenemase- and ESBL-producing Enterobacterales. That makes it notable beyond niche dairy science: the researchers are asking whether a biologically active milk long discussed for its antimicrobial properties might show activity against pathogens that sit at the center of the global AMR challenge. (who.int)
There’s already a scientific backdrop for that question. Donkey milk has been studied for years as an unusual dairy matrix with relatively high lysozyme content and other bioactive proteins, and previous work has reported inhibitory effects against selected pathogens. A 2020 Animals paper found antimicrobial activity in raw donkey milk against some indicator organisms, while a 2023 Animals study from Serbia reported growth-inhibitory effects and pointed to lysozyme and lactoferrin as likely contributors. Reviews published in 2024 and 2026 similarly describe donkey milk’s antimicrobial potential, especially through whey proteins, peptides, and iron-binding mechanisms. (mdpi.com)
What appears to set this new paper apart is the target panel. According to the article abstract provided, the team evaluated activity against 10 clinical Enterobacterales isolates carrying resistance mechanisms such as CTX-M, OXA-48, KPC, NDM, and VIM. Those markers matter because they’re associated with some of the hardest-to-treat Gram-negative infections in both human and veterinary-adjacent settings. WHO’s 2024 Bacterial Priority Pathogens List continues to place resistant Gram-negative bacteria among the most urgent threats for research and public health action. (who.int)
The pasteurization angle is also important. Donkey milk is marketed as a high-value product, but safety requirements still push commercial supply toward heat treatment. Prior studies suggest that standard pasteurization can reduce microbial load while preserving a meaningful share of lysozyme activity, and recent work has emphasized that maintaining those bioactive properties is central to the product’s value proposition. In other words, if pasteurized donkey milk retains measurable growth-inhibitory activity, that would strengthen the case that the effect is not limited to raw milk alone. (mdpi.com)
Outside commentary on this exact paper was limited in available web results, but the broader literature is fairly consistent on mechanism. Reviews and experimental studies repeatedly point to lysozyme, lactoferrin, immunoglobulins, and bioactive peptides as the most plausible drivers of donkey milk’s antibacterial effects. Some authors also note that activity against Gram-negative organisms may depend on synergistic interactions rather than a single compound acting alone. That’s an important nuance, because it suggests any downstream therapeutic or nutraceutical application would likely require fractionation, standardization, and careful validation rather than simple whole-milk use. (mdpi.com)
Why it matters: For veterinary professionals, the study is best read as early translational research with One Health relevance. Resistant Gram-negative organisms don’t respect the boundary between human, animal, and environmental health, and the search for new antimicrobial strategies increasingly includes biologically derived compounds. But the practical takeaway today is restrained: an in vitro growth-inhibition finding is not evidence of therapeutic efficacy in animals, and it doesn’t override food safety concerns around raw milk. The value here is in expanding the pipeline of ideas, especially as conventional antibiotic development continues to lag behind the pace of resistance. (who.int)
There are also commercial and regulatory implications in the background. Donkey milk remains a niche, costly product, and recent quality-control research has highlighted how important pasteurization verification and preservation of nutraceutical components are for the sector. If future studies can identify a reproducible antimicrobial fraction that survives processing, that could matter for both dairy innovation and biomedical research. For clinicians, though, this remains firmly upstream from practice. (mdpi.com)
What to watch: The next steps are clear: full-text data on which isolates were most affected, whether raw and pasteurized milk differed meaningfully, dose-response and mechanism studies, and eventually animal-model or applied translational work that tests whether these in vitro observations have any real clinical relevance. (mdpi.com)