Darwin’s law applies to bacteria

Penicillin didn't work on pneumonia

Most of us have heard of the theory of “survival of the fittest” as the underpinning of the evolution. I am aware that  many still reject that explanation for the stunning variety in nature, although most educated people accept Charles Darwin’s theory as a plausible hypothesis.

Shortly after I had graduated from medical school and was still in training before the authorities had granted me a full license to practice, I got a real life lesson in the validity of Darwin’s premise; a lesson I will never forget.

It was my turn to evaluate every arrival at the emergency department of the hospital where I trained. That meant interviewing and examining patients, ordering tests, arriving at a working diagnosis, and then calling my supervisor, who would confirm or modify the diagnosis. Subsequently, the attending physician would ask me to propose an appropriate treatment or solution of the presenting problem and I could not proceed without his approval.

It was late in the afternoon when a 19-year-old student by the name of Steve was brought in by a friend.

The friend told the admissions clerk he was concerned about Steve’s condition, that he had trouble breathing and could only take a few steps at a time. He was normally quite an athlete and had been well until that morning.

In the course of the day he started to cough more and became increasingly short of breath.

The clerk took one look at Steve and saw the young man was in deep trouble. She alerted both the nurse and me and while the friend looked after the paperwork, Steve was put on a stretcher and given oxygen.

Until then, he had so much trouble breathing that he could not speak, but the oxygen helped quite a bit and Steve could answer some questions.

The evening before he had gone out for a run and was sweating when he got back home. Just before he wanted to go in, two friends stopped by and they chatted for a while outside. There was a bit of a cold breeze and he felt chilly before he went in. He had slept well but when he woke up he had a bit of cough and thought he had caught a cold. As the day progressed he got worse.

Even though the oxygen helped, he looked quite ill, had a high fever and coughed incessantly, but was unable to cough up any phlegm.

When I put my stethoscope to his chest to listen to his lungs, there wasn’t a spot where his lungs sounded normal. Within minutes we had arranged for an X-ray of his chest which revealed an ominous picture. Both lungs looked as if they had been filled with snowballs. That could only mean one thing – and that was staphylococcus pneumonia.

For a number of years we had used penicillin as the cure-all for most infections, including pneumonias. We classify bacteria in gram-positive and gram-negative organisms and until the mid-50s we could kill virtually all gram-positive bacteria with penicillin.

We knew there were many kinds of bacteria, but we did not know that not all staphylococcus bacteria were the same.

Some were stronger than others and the strongest ones survived when exposed to penicillin. Once all the other bacteria had been knocked off by the penicillin, these strong ones could multiply with impunity.

And multiply they did – and became a real menace for people who became infected with this particular strain of bacteria. It took a few years to develop a new antibiotic that could deal with this resistant staphylococcus, but until then, many people succumbed.

Unfortunately, those new antibiotics were not available when Steve developed the resistant staphylococcus pneumonia and by midnight, he died in spite of our best efforts.

I will never be able to erase the image of this promising young man struggling for breath and slipping away, while we could do nothing to prevent it. It was then I realized that Darwin’s theory applies to bacteria just as much as it did to the flora and fauna of the Galapagos Islands.

 

Dr. Marco Terwiel is a retired family physician who lives in Maple Ridge.