The Conversationalist Take 2: Bovine Respiratory Antibiotic Use Relative to Human Antibiotic Resistance…

For my sixteenth birthday I went for a glider plane ride with one of my swimming teammates, Bill.  Bill’s birthday was just a few days away from mine, and we decided to do something “daring” to celebrate my 16^th birthday and his 23^rdbirthday.  Bill had graduated from college and was taking a year off to train for the Olympic Trials, and we became “training buddies”.  As “training buddies”, we spent about 30 hours a week together swimming and lifting weights.  In between training sessions, I went to high school and Bill worked as a lifeguard.

Here I am with our Coach, and Bill can be seen in the background. As part of our training, we competed in 1 mile ocean races. If my memory serves me right, this was right after Bill and I took 1st and 2nd places in the race...

I am not a naturally “daring” person, so my parents were pretty much astounded when I told them what Bill and I had planned.  In fact, I believe the looks shared by my parents when they heard our plan distinctly resembled the looks that they shared when I told them that I was getting married and moving to Nebraska to work at a cattle feed yard.

An aerial photo of my cattle feed yard...

Twenty years later and 2000 miles apart, Bill and I are still friends.  He is one of Feed Yard Foodie’s most loyal readers, and he left an interesting comment last week regarding the correlation between antibiotic use in humans and cattle relative to pneumonia infections.  I would like to take a moment to address the topic.  The information that I am going to share with you comes from Dr. Mike Apley DVM, PhD, DACVCP who teaches Pharmacology at Kansas State University’s College of Veterinary Medicine.  Dr. Apley is an expert on the topic of antibiotic use and resistance.

The Truths of Antibiotic Use and Resistance Relative to Respiratory Infections in Cattle and Humans:

1. Respiratory pathogens (like pneumonia) in humans and cattle are different.  When we get ill, the “bugs” that cause the infection in humans are different from the “bugs” that cause the infection in cattle.  There is a species difference in pathogens causing respiratory illness.
2. Cattle farmers (like me) use the Beef Producers Guide for Judicious Use of Antimicrobials in Cattle that were created by Dr. Apley and other veterinarians and animal scientists.  They are:

• Prevent Problems: Emphasize appropriate husbandry and hygiene, routine health examinations, and vaccinations.
• Select and Use Antibiotics Carefully: Consult with your veterinarian on the selection and use of antibiotics. Have a valid reason to use an antibiotic. Therapeutic alternatives should be considered prior to using antimicrobial therapy.
• Avoid Using Antibiotics Important In Human Medicine As First Line Therapy: Avoid using as the first antibiotic those medications that are important to treating strategic human or animal infections.
•  Use the Laboratory to Help You Select Antibiotics: Cultures and susceptibility test results should be used to aid in the selection of antimicrobials, whenever possible.
•  Combination Antibiotic Therapy Is Discouraged Unless There Is Clear Evidence The Specific Practice Is Beneficial: select and dose an antibiotic to affect a cure.
•  Avoid Inappropriate Antibiotic Use: Confine therapeutic antimicrobial use to proven clinical indications, avoiding inappropriate uses such as for viral infections without bacterial complication.
• Treatment Programs Should Reflect Best Use Principles: Regimens for therapeutic antimicrobial use should be optimized using current pharmacological information and principles.
• Treat the Fewest Number of Animals Possible: Limit antibiotic use to sick or at risk animals.
• Treat for the Recommended Time Period: To minimize the potential for bacteria to become resistant to antimicrobials.
• Avoid Environmental Contamination with Antibiotics: Steps should be taken to minimize antimicrobials reaching the environment through spillage, contaminated ground run off, or aerosolization.
• Keep Records of Antibiotic Use: Accurate records of treatment and outcome should be used to evaluate therapeutic regimens and always follow proper withdrawal times.
• Follow Label Directions: Follow label instructions and never use antibiotics other than as labeled without a valid veterinary prescription.
• Extra label Antibiotic Use Must follow FDA Regulations: Prescriptions, including extra label use of medications must meet the Animal Medicinal Drug Use Clarification Act (AMDUCA) amendments to the Food, Drug, and Cosmetic Act and its regulations.  This includes having a valid Veterinary-Client-Relationship.
• Sub therapeutic Antibiotic Use Is Discouraged: Antibiotic use should be limited to prevent or control disease and should not be used if the principle intent is to improve performance.

 3. In order for antibiotic resistance in human drugs to develop from antibiotic use in food animals ALL of the following steps must occur:

• Bacterial populations in the bovine animal are exposed to antimicrobials (antibiotics) on the farm.   A bovine animals gets sick with a bacterial infection and is then treated with antibiotics on the farm.
• Selection for resistant organisms due to the antimicrobial treatment occurs in the bovine animal. Instead of the antibiotic curing the infection and killing all of the bugs, some bugs are left and become resistant to the antibiotic.   (If the antibiotic is administered correctly according to veterinarian and drug label instructions, this should not occur.)
• After selection occurs (which should not happen—see above), there must then be an increased incidence of resistant organisms in the bovine animal.  The number of resistant organisms must grow.
• Then, a transfer of these resistant organisms must occur through the food chain or through direct transfer to a human.  In other words, the “bug” must make the jump from the bovine to a human.
• Then, a presence of food animal derived resistant bacteria must occur in a human.  The resistant bug must survive the “jump” and grow in the new human host.
• Then, the food animal derived resistant bacteria must contribute to a human disease infection. In other words, the resistant bovine respiratory “bug” must make the human sick. (Another unlikely occurrence because the respiratory “bugs” that affect humans and bovines are not the same).
• Finally, treatment failure or prolonged disease must occur due to pathogen (infectious bug) resistance.

Completion of all seven of these steps is highly unlikely, and therefore, it is believed by experts (like Dr. Apley) that when I use a cephalosporin antibiotic to treat a bovine with a pneumonia infection that it is NOT contributing to antibiotic resistance in human pneumonia pathogens.  When I use a cephalosporin at the feed yard to treat respiratory illness, it is highly effective at treating the disease.  This demonstrates that step 2 (of the 7 steps) is not attained, and consequently steps 3-7 cannot occur.  This means that the use of antibiotics to fight respiratory infections in my cattle do not contribute to antibiotic resistance in the human population.

Therefore, Dr. Apley reports that no scientific data exists to support the idea that a correlation exists between the uses of antibiotics in the treatment of respiratory illness in bovines with an emergence of an antibiotic resistant respiratory “super bug” in humans.

You can feel good about serving this to your family: it is safe and healthy and tastes great too!

Bill, I am sure that by now, you are wishing that Coach Andersen would give me a really long swimming work out so that I was forced to stop talking.  Some things never change, and I still am an opinionated female!  I have, however, done a lot of homework on this incredibly complex issue and hope that you find this post insightful…