Notes from the Lab: We’re Making Blood Broth!

This is not a leftover Halloween-inspired vampire joke, our researchers actually make blood broth once a week!

Day in and day out our researchers are on the hunt for bacteria. To help unearth different types of bacteria, we have to create living conditions where the bacteria can thrive. Enter blood broth, a type of enrichment broth used to coax certain bacteria to multiply (i.e., grow -- we still haven’t figured out how to make them do math). Different bacteria thrive under different conditions. For example: Campylobacter likes to grow in a broth supplemented with blood while Salmonella and E. coli prefer broths supplemented with sugars and proteins.

For our current research project, we are studying several bacteria (E. coli, Salmonella and Campylobacter) found on raw chicken sold in grocery stores in California to determine if the bacteria we find is resistant to antibiotics. As a result, we are currently mixing our own blood broth to help us identify and grow Campylobacter, a bacteria that causes an estimated 1.3 million illnesses each year in the United States.

To mix it, we add horse blood to a broth base that encourages growth of Campylobacter. This mixture works in two ways: 1) It contains ingredients to resuscitate injured Campylobacter cells and 2) It works to encourage Campylobacter to grow in the broth. A supplement is also added to inhibit the growth of other types of bacteria.

Once our chicken has spent at least 48 hours in the enrichment broth, we isolate the Campylobacter by spreading some of the broth on petri dishes to separate it from other bacteria. You can learn more about what happens next by reading our previous installment, Hunting for Bacteria in Our Lab.

According to the U.S. Centers for Disease Control and Prevention, most Campylobacter infections occur due to eating undercooked poultry, handling raw poultry or by eating something that touched raw poultry products. Additionally, some infections are due to contaminated water, contact with animals, or drinking raw (unpasteurized) milk. While healthcare professionals rely on antibiotics to treat patients with severe Campylobacter infections, the use of antibiotics in poultry production can select for Campylobacter strains that are resistant to these treatments. Click for more information from CDC on Campylobacter.