Allies and Enemies: How the World Depends on Bacteria (9 page)

During the plagues, clergymen insisted as they had for centuries

that sickness came as penance from God. Their ineffective efforts to

administer to the dying by combining faith and sorcery caused the church to lose its customary privileged status in society. The banking profession gained stature, however, for two reasons. The plague’s survivors understood the need for protecting assets for the next generation, especially when death could strike so suddenly. At the same time, serfs abandoned fields controlled by feudal landowners and chapter 2 · bacteria in history

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took advantage of monetary pay to fill labor shortages in the cities.

This in turn helped create a mobile workforce that covered Europe in

search of the highest wages in labor-starved towns. Young adults left

as the sole managers of family property opted against traveling to traditional centers of learning in Paris, Vienna, or Bologna. New centers of education thus developed in Oxford, Cambridge, Edinburgh, Amsterdam, Copenhagen, and Stockholm by the 14th century. The

depopulation of the European continent also opened up new land for

cultivation or development and laid the foundation for the industrial

centers of today’s Europe.

Surgeons had been as useless as clergymen during the plagues.

The status of the surgeon would decline and not rebound until the

mid-19th century when Joseph Lister invoked the need for sterile conditions in hospitals. Barbers came to the fore as more trustworthy medical practitioners despite their penchant for bloodletting as an all-purpose cure. But what is now known as western medicine also advanced. Medical schools grew and students for the first time learned anatomy and physiology. As a result, the medical community

began learning about the effects of infectious disease on internal organs.

With each of these historical plagues, survivors learned better precautions for escaping infection. Bubonic plague is not contagious, but streets filled with the dead and dying certainly showed that anyone could fall victim. Plague survivors gingerly removed the bodies and took them to the countryside where funeral pyres awaited. This had been the commonest method of disposal throughout the Middle Ages, but on

occasion people used more imaginative ways to dispose of corpses.

From 1344 through 1347, Tartars laid siege repeatedly to the port

city of Caffa (now Feodosija, Ukraine), home to diverse nationalities

and political persuasions. The plague had already laid waste to the Tartars’ homeland of eastern Asia, and deaths among them mounted even as they surrounded the city. With a body count mounting, the

Tartars disposed of their deceased by the simple expediency of cata—

pulting the cadavers over Caffa’s walls. Caffa’s healthy residents would be infected when they collected the bodies for burial. Thus bacteria and humans forged a complex relationship involving disease, sustenance, evil, and God.

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Microbiologists save the day

In 1822 Louis Pasteur was born into a family that had made its living

tanning hides for generations. A lackluster student, only chemistry held Pasteur’s interest. By the time he reached college, Pasteur would spend hours studying structures of organic compounds and this pursuit likely awakened a curiosity about biology. Still, Pasteur thought of himself as foremost a chemist.

After winning election as France’s president in 1848, Napoleon

Bonaparte III made transportation, architecture, and agriculture the

country’s priorities. New edicts pressured university scientists to follow commercial pursuits. As a professor at the University of Lille, Pasteur grudgingly tucked away his chemistry equipment and brought a microscope into his lab without a clear plan for using it. He decided to teach students about biology’s relationship to agriculture until the time came when he could return to his chemistry experiments.

Pasteur’s “temporary” foray into biology initiated the most accomplished career in microbiology’s history. His publication list lengthened, and his reputation grew inside and outside of science. By the 1850s, Pasteur had been recruited by France’s alcohol manufacturers

to improve their fermentation methods. He began by investigating yeast fermentations, perhaps because brewers had not studied it in detail. Pasteur noticed that a drop of liquid from the fermentation flasks gave a curious result in the microscope. When Pasteur put a glass cover slip on top of the drop, some of the microbes avoided the edges of the slip where the liquid was exposed to the air. Pasteur introduced biology to anaerobic bacteria.

By describing processes taking place in fermentation, Pasteur

gave the wine and brewing industries greater control over their manufacturing steps. His reputation soared when he diagnosed a disease that had been decimating France’s silk industry. By the 1860s, Pasteur reached national hero status. (Pasteur had incorrectly identified bacteria as the cause of the silkworm disease. Electron microscopes

were not yet available to enable him to find the real cause: a virus.

Pasteur nevertheless made the crucial and previously overlooked

connection between microbes and infection.)

The public adored Louis Pasteur. Napoleon III invited the microbiologist to his table to hear the latest theories on microbes, and

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Pasteur happily obliged. He, in fact, had developed the habit of dismissing anyone who questioned his work. Pasteur also cultivated the ability (or flaw according to some) of drawing scientific conclusions even while producing little data to back them. Louis Pasteur possessed such a rare and keen insight into biology that his conclusions almost

always proved to be correct. One famous misstep occurred in 1865

during a cholera outbreak in Paris. Pasteur believed the pathogen Vibrio cholerae transmitted through the air though it is a waterborne pathogen. The French nonetheless felt relieved to know that Pasteur was hard at work trying to save them from cholera. The Paris epidemic

ran its course and disappeared on its own.

During a rabies scare in 1885, Pasteur concocted a treatment and

gave the untested drug to a nine-year-old boy, Joseph Meister, who

had been bitten by a grocer’s dog. Three weeks later, Meister had almost fully recovered. Pasteur’s legend received considerable help by the fact that Meister hailed from Alsace, a region controlled by Germany but claimed by France. The tricolor declared a victory for French science and for Pasteur who had beaten the German, Robert

Koch, who had like Pasteur been working on vaccines. As a grown man, Joseph Meister took a job as a guard at the Institut Pasteur after Pasteur’s death. When German troops entered Paris in 1940, they swarmed the institute’s grounds and ordered that Pasteur’s crypt be opened. Meister likely had been one of several men who defended

the crypt against the Wehrmacht and prevented its defilement.

Shortly after, Meister inexplicably shot himself through the head.

Even this act became part of Pasteur’s celebrity. Historians would write that Meister committed suicide in front of the Germans rather than disturb Louis Pasteur, France’s hero.

Pasteur’s influence on microbiology cannot be captured in a few

pages. Early in his career, Pasteur had disproved the long-held theory

of spontaneous generation, the belief that microbes and all other life

arose from inanimate things: rocks, water, or soil. Biologists had already begun taking sides on this issue prior to Pasteur. As their science matured, many microbiologists doubted the logic behind spontaneous generation—science was increasingly distancing itself from spiritual dogma. Pasteur developed an experiment that unequivocally showed that a flask of sterilized broth could not produce life on its

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own. Pasteur modified this flask with an S-shaped tube to serve as the

opening. This configuration let in air but prevented any particles from the air to enter. A second sterile flask left open to the air was soon teeming with bacteria but the S-flask remained sterile. Elegant

in its simplicity, Pasteur’s experiment earned him respect from his contemporaries.

During his career, Pasteur also distinguished between anaerobic

and aerobic metabolism, invented the preservative method to be

known as pasteurization, and developed the first rabies and anthrax

vaccines (see Figure 2.3). As a postscript, the original S-flask is on display at the Institut Pasteur today and remains sterile.

Figure 2.3 Bacillus anthracis, the anthrax pathogen. B. anthracis and all other Bacillus species form a tough, protective endospore. In this picture, endospores in phase-contrast microscopy look like bright ovoid balls inside an elongated cell. (Courtesy of Larry Stauffer, Oregon State Public Health Laboratory)

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When bubonic plague erupted in Asia in the late 1800s, Pasteur

dispatched Alexandre Yersin of the French Colonial Health Service

to investigate. Microbiologists had by that time a century of using ever-improved microscopes, and they had become skilled at diagnosing disease by examining patient specimens to detect pathogens. In 1894, Yersin and a bacteriologist sent by Japan’s government, Shibasaburo Kitasato, rushed with other public health officials to Hong Kong where a localized plague outbreak was emerging. Within a week Yersin isolated a rod-shaped bacterium from a plague victim.

Kitasato found a similar microbe, but because the two men conversed

only in broken German, they shared little of their findings. Yersin sent his report to the Institut Pasteur in Paris. Kitasato forwarded his results to Robert Koch in Berlin. In most circumstances, two scientists having attained the prominence in their profession as Pasteur and Koch had would have shared their data and drawn mutually agreed-upon conclusions. But Yersin and Kitasato’s place in history would hinge on a rivalry between Pasteur and Koch that began

12 years earlier.

Pasteur and Koch held different perspectives on bacteria. Pasteur

focused on the interplay between the body’s immune system and bacterial pathogens and felt that virulence in pathogens changed over time, creating more or less virulent strains depending on environmental influences. Koch believed pathogens to be less variable and always capable of releasing virulence factors if opportunities for infection arose. Their differences would have made for lively and good-natured discussions had not Pasteur accidentally insulted Koch’s “German arrogance” at a meeting in Geneva in 1882. Pasteur had actually praised Koch’s body of work on anthrax and tuberculosis bacteria to the audience, but a scientist sitting next to Koch struggled to keep up with Pasteur’s speech and translate it into German for his colleague.

Unbeknown to Pasteur or Koch, the translator had made a mistake in

going from French to German. In an age lacking telecommunications

gadgets, the misunderstanding persisted. Koch returned to Berlin with contempt toward Pasteur that he made no effort to conceal.

When Pasteur published details of his successful rabies vaccine in

1885, Koch dismissed the work, insisting that a vaccine made of attenuated viruses needlessly endangered patients. But an underlying

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animosity likely arose out of each man’s patriotism and the border conflicts between France and Germany over the Alsace and Lorraine regions. Koch undoubtedly remembered that Pasteur had received

an honorary degree from the University of Bonn in 1868, but

returned it later during the height of French-German tension. “Today

this parchment is hateful to me,” Pasteur wrote to the university dean, “and it offends me to see my name, which you have decorated with the qualification virum clarissimum, placed under the auspices of a name that will henceforth be loathed by my country, that of Guillermus Rex
.” The Germans responded with equal vitriol with both letters ending up printed in local newspapers.