Animal Health

The rise and fall of antibiotics

By Gemma Chuck

PERHAPS ONE of the greatest medical breakthroughs of our age was the discovery of penicillin by Alexander Flemming in 1928.

New antibiotics were rapidly discovered which revolutionised the means by which infectious diseases were treated.

Common human infections became easily curable and outbreaks of infectious disease were readily controlled. However, just a few years after the golden age of antibiotics, warning signs of developing resistance were observed.

Just as Flemming had predicted, previously susceptible bacteria were evolving and mutating to develop resistance to antibiotics at an alarming speed.

Although the magnitude of this problem is still unclear, it is proposed that abuse and misuse of antibiotics is largely responsible for the development of resistance.

In less than 100 years after antibiotic discovery, we now face a grim scenario for the generation to come where most antimicrobials might no longer be effective. Human and veterinary medicine may once again enter an era where common bacterial infections could once again prove lethal.

Antibiotic usage in food animals improves more than just animal wellbeing but also has economic benefits for food animal producers along with a safer public health sector.

Significant quantities of antibiotics are used in animal production industries and consequently the incidence of antibiotic resistance has increased.

Antibiotics are a valuable tool in the dairy industry, and when used responsibly, they are vital for the maintenance of good animal health and welfare.

Bacterial resistance to these valuable treatments is considered a threat to the viability of dairy farming and consequently a threat to human health.

Everyone who is involved in the use of antibiotics is responsible for helping prevent antibiotic resistance. In the dairy industry this includes farmers, farm workers, veterinarians, and pharmaceutical companies.

New dairy technology aids antibiotic use

Knowledge of the resistance status in your herd is the key to choosing the right treatments for your cows, and for monitoring and preventing the development and spread of resistance.

However, bacterial resistance to antibiotics is not as clear cut as being resistant or susceptible. Most mechanisms of bacterial resistance depend on the concentration of the antibiotic present.

The Dairy Antibiogram is a new technology, developed by Bayer Animal Health, and is performed on a simple bulk milk tank sample.

It detects and monitors antibiotic resistance in the two most common mastitis bacteria, Staphylococcus aureus and Streptococcus uberis, and assesses a range of antibiotics.

The test measures the minimum concentration of an antibiotic to prevent bacterial growth, allowing veterinarians and farmers to make informed decisions on the most effective treatments.

Using this data, an antibiogram can be developed for individual bacteria and compared over time to detect new levels of antibiotic resistance.

Dairy farmers, in conjunction with their veterinarians, now have a unique opportunity to build reliable susceptibility testing into their mastitis programs, and to use this data to guide responsible antibiotic use.

Dairy Antibiogram adds value to industry

A Dairy Antibiogram can give you valuable information which, with the direction from your veterinarian, could help you:

  • Plan to use effective mastitis treatments.
  • Know the resistance status of your herd and how this compares to other herds in Australia.
  • Develop a biosecurity plan to protect a ‘good’ resistance status.
  • Identify potential ‘resistance’ issues in your herd, allowing further investigation and management.
  • Monitor your resistance status over time.
  • Help the dairy industry demonstrate responsible antibiotic usage.

As with all new technologies the uptake of this test in Australia has been variable so far.

The technology and reporting are very promising and have the potential to be considered a routine surveillance tool in the future.

If you would like to know more about the Dairy Antibiogram, call your local veterinary clinic to discuss how it could help with the management of mastitis and use of antimicrobials in your herd.

The author has no affiliations with (financially or otherwise) Bayer Animal Health or the Dairy Antibiogram as discussed in this article.