The reason we should all study microbiology
During the first day of class, I stated that I perceive society today as facing two critical epidemics. For those of us living in developed societies, disease due to inadequate exercise, tobacco use, and poor dietary choices has led to alarming numbers of people facing issues of all forms of cardiovascular disease and other conditions such as diabetes. In that lecture, I made the assertion that although health care workers may have some influence over the choices of their patients, changes in the lifestyle of the patient enabling resolution of these diseases are ultimately in the hands of those patients. The other epidemic we face is that due to infectious agents, including emerging infectious disease which have not been previously associated with significant human disease, and the emergence of multiply drug resistant isolates of existing infectious agents. I further asserted that point of contact health care workers will be a significant force in helping to curb this epidemic.
Which brings us to today’s Microbes in the News offering. It may not be immediately obvious why we face an epidemic of emerging infectious disease, but many of them are due to the conveniences of modern society and the way we live our lives. Two important concepts in infectious disease are reservoirs (where a microorganism can survive outside of a human host), and vectors for transmission of infectious agents. The linked article from WebMD article discusses evidence that antibiotic resistant strains of bacteria can arise due to the high levels of antibiotics that are used in farming to promote animal growth and health. The high levels of exposure in agriculture puts selective pressure on microbes in the environment, resulting in acquisition of antibiotic resistance broadly in microbial populations.
This is not a new finding; modern agriculture has been known to be a factor in the emergence of antibiotic resistant strains of infectious agents, and is one that we will discuss in class later in the term, along with other inappropriate uses of antibiotics. What is novel in this report is the description of the role that common insects can play in the spread of infectious agents. Authors at Kansas State and North Carolina State Universities found that flies and cockroaches recovered adjacent to pig farms were able to transmit many organisms associated with gastrointestinal disease, including Enterococcus faecalis. The isolates of these bacteria that were recovered from the insects were identical to strains found in pig manure. The conclusions of the studies were that the insects were serving as mechanical vectors of transmission to neighboring residential areas. So merely ensuring that your pork chops are cooked to an appropriate internal temperature is no longer enough; you now need to ensure that your Caesar Salad hasn’t been touched by flies which have visited from the farm next door!
Bonus opportunity: Based on what we are learning in Chapter 6, what can you conjecture about the growth requirements or the nutritional requirements of the organisms that this article mentions? How do you think they might be isolated or studied in the laboratory?