Magazine article American Scientist

First Person: Herman O. Sintim

Magazine article American Scientist

First Person: Herman O. Sintim

Article excerpt

Antibiotic resistance is on the rise, and we are potentially facing a time when standard antibiotics simply won't work anymore. Herman O. Sintim, an organic chemist at Purdue University and a Sigma Xi Distinguished Lecturer, is developing novel ways to target bacteria that cause illnesses. His approach is to prevent them from producing the toxins that lead to illness, rather than killing them. That kind of intervention avoids placing selection pressure on the bacteria, and so should reduce the chances that the bacteria will develop resistance to the intervention. Sintim discussed his research with managing editor Fenella Saunders. (A video of the full interview is available on the American Scientist website.)

Why is antibiotic resistance becoming more widespread?

Resistance is said to occur when the dose of the drug that is used doesn't work anymore. There are several reasons why those doses don't work. Some could be that a type of bacteria has developed molecular mechanisms that actually make the drug ineffective. It turns out that they also have the ability to pass on the know-how to make these drugs ineffective to other bacteria. That makes it quite problematic that it only takes one bacteria to require resistance for that bacteria to pass that knowledge to other bacteria for them also to become resistant.

Why is the increase in bacterial resistance a serious issue?

This problem is like a time bomb, and if we don't tackle it, it's actually going to explode in our faces. Currently, only a small percentage of clinical cases are due to resistant bacteria, but there have been some projections that if newer drugs are not developed against these resistant bacteria that already exist, by the year 2050, death from antimicrobial resistant bacteria could actually even surpass death from cancer. This is a big problem.

Why is resistance on the rise?

The misuse of antibiotics has certainly contributed to the resistance phenomena. A lot of antibiotics are used in farming. That leads to some resistance, because whenever any pressure is put on bacteria, the bacteria will come up with resistance. Having said that, resistance is actually an ancient mechanism. A whale researcher found that some bacteria that were present in the northern Arctic actually had Vancomycin resistant genes in them. Some of these resistant genes came about not necessarily because of the clinical use of antibiotics, but because bacteria use these molecules in fighting amongst themselves. Some are ancient mechanisms, but we have certainly helped in propagating these resistant genes.

What are common bacterial mechanisms of resistance to drugs?

An analogy is someone coming into your home who is unwelcome. The easiest way to get rid of that person is to grab that person and then throw them out of the door. Bacteria use that tactic in the sense that they have what are called efflux proteins that are membrane-bound. When the drug gets into the bacteria cell, these proteins are very promiscuous. They bind to drugs and pump them out of the cell. Other bacteria have come up with an enzyme that degrades the molecule that is supposed to work on those bacteria targets.

What alternate methods are you developing for targeting bacteria?

I am encouraged by the fact that there are more than 200 different bacteria species that live in our gut. The majority of them are actually beneficial to us. It turns out that we have learned to live with bacteria and bacteria have learned to live among each other, because different cell types communicate among themselves. The new paradigm is to come up with a strategy that would stop bacteria from producing the toxins, the virulence factors that actually make us ill, without killing bacteria. The idea is that if such pressure is not put on bacteria, then there will be no evolutionary pressure for the bacteria to develop resistance.

A few decades ago, a very interesting discovery was made that bacteria actually communicate with one another using small molecules, which are responsible for the expression of so many toxic genes. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed


An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.