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Ceftiofur Treatment in Dairy Cows: Impact on Antimicrobial Resistance and Microbial Diversity

By Claudia Ossa-Trujillo | Graduate Student in Biomedical Sciences

Two black and white dairy cows standing in front of a lake.

Antimicrobial resistance — in which microorganisms, like bacteria, become resistant to the medications used to treat them — is a significant concern worldwide for animals and people. Ceftiofur crystalline-free acid (CCFA) is one formulation of a third-generation cephalosporin (3GC) in the β-lactam class of antibiotics approved for use in veterinary medicine; further, it is the preferred antibiotic for treating acute bacterial metritis (inflammation of the uterus) in dairy cows.

Metritis causes significant economic loss for the dairy industry in the United States as it reduces milk production, reproduction, and herd survival in affected dairy cows. However, using CCFA in cattle may lead to the development of resistance to this and other antibiotic classes that are important in human and veterinary medicine. There is also a potential risk for these antimicrobial-resistant bacteria to transfer from livestock to humans through the food chain and environment, which could lead to broader dissemination.

It is important to note that the World Health Organization (WHO) considers the 3GC class of antibiotics the highest priority and most critically important for human medicine. However, the effect of 3GC antibiotics on the microbial communities of cattle and resistance within these communities is largely unknown.

The objectives of this study were to determine the effects of two-dose CCFA regimen on the fecal microbiota and the quantities of several antibiotic-resistance genes present in fecal samples from Holstein-Friesian dairy cows with a diagnosis of metritis in the southwestern United States. These were compared to cows without such a diagnosis.

The research findings suggest that two-dose CCFA treatment in dairy cows with metritis elevates the quantities of cephamycinase (blaCMY-2) — a gene that confers antibiotic resistance to certain β-lactam antibiotics— among all fecal bacteria while paradoxically increasing microbial diversity. However, it does not have dramatic selection effects on another class of important extended-spectrum beta-lactamase (ESBL) genes (blaCTX-M). This study is important because it demonstrates that administering two-dose CCFA in dairy cows enhances the cephamycinase gene.

This study was published in the Microorganisms journal from MDPI and supported by the extramural research program of the U.S. Department of Agriculture, National Institute of Food and Agriculture, Agriculture and Food Research Initiative (2016-68003-24607).

Filling The Gap: Down Syndrome, Bone Health, And Fracture Healing

Filling The Gap: Down Syndrome, Bone Health, And Fracture Healing

By Kirby Sherman | Ph.D. candidate in Biomedical Sciences
Department of Veterinary Physiology & Pharmacology

Down syndrome (DS), the most common birth defect in the United States, alters human development and leads to a variety of clinical issues, including low bone mass and strength. Because people with DS are living longer, more active lives, their risk of bone fracture has increased.

However, there is a significant gap in knowledge regarding DS and fracture healing, and it remains unknown if people with DS are able to heal fractures. This observation of the lack of research surrounding DS and bone health was first made in the laboratory of Dr. Larry Suva, in the School of Veterinary Medicine & Biomedical Sciences Department of Veterinary Physiology & Pharmacology. Indeed, the risk of fractures is a major health concern for the DS community and can severely impact their quality of life.

Due to the increased risk resulting from decreased bone mineral density observed in DS people, our work sought to understand how DS impacts the ability to heal a fracture. Ultimately, we determined that when individuals with DS fracture a bone, that bone is unlikely to heal. We also discovered the reason why these bones fail to heal (called non-union), namely inflammation and a defect in bone repair.

Importantly, fractures that fail to heal can be fatal, even in young people with no previous health concerns. With this new awareness of the problem, we hope there will be more widespread adoption of measures to increase bone strength, more careful monitoring when fractures do occur, and that physicians and others will consider the bone health of people with DS a priority for their care.