Drug-Resistant Bacteria: Evidence for Evolution (Part 2)

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Textbooks often call drug-resistant bacteria prime “evidence for evolution.” Let’s apply some of the 7 Checks of Critical Thinking to a real textbook example of this claim.

Whether in high school textbooks or documents shaping international policy, no argument for evolutionary origins would seem complete without a nod to drug-resistant bacteria. A report for a resolution entitled “The Dangers of Creationism in Education,” which the Parliamentary Assembly of the Council of Europe passed in 2007,1 touted bacterial resistance as prime evidence for evolution, stating,

Denying [evolution] could have serious consequences for the development of our societies. . . . Evolution is present everywhere, from medical overprescription of antibiotics that encourages the emergence of resistant bacteria to agricultural overuse of pesticides that causes insect mutations on which pesticides no longer have any effect.2

The idea is that as doctors prescribe antibiotics to fight bacterial infections in patients, natural selection can favor any bacteria which survive the antibiotic exposure for various reasons. Entire populations of bacteria may eventually become resistant to multiple antibiotics, so the medical community is constantly seeking new ways to target these “superbugs.” We can observe this process happening, and many people call it “evolution.”

The Textbook Story

Under the heading, “Evolution is supported by an overwhelming amount of evidence,” my first-year biology textbook explained how within two years of penicillin’s becoming a widespread drug, some harmful strains of Staphylococcus aureus bacteria became resistant to penicillin.3 As the textbook put it, “These bacteria had an enzyme, penicillinase, that could destroy penicillin.”4 So, doctors began using other antibiotics, including methicillin, which inactivates a protein that the bacteria require to build their cell walls.

Again, within two years, methicillin-resistant bacteria appeared. As my textbook put it, “some individuals were able to synthesize their cell walls using a different protein that was not affected by methicillin.”4 The textbook considered this amazing evidence for evolution as a whole. But is that true? Let’s think about it, using some Checks of Critical Thinking.

Thinking About Drug Resistance

Check 1: Check Scripture5

Genesis indicates God created organisms to reproduce according to their kinds. In this case, we’re ultimately seeing Staphylococcus bacteria producing more Staphylococcus bacteria.6 That’s not a problem, from a biblical perspective. We might ask how some of these bacteria began causing disease after sin corrupted the universe that God had deemed very good;7 you can find answers starting here.

Check 2: Check the Challenge

While the observational science does not challenge any biblical doctrines, the conclusion that drug-resistant bacteria show all life evolved naturalistically does challenge clear teachings of Scripture. (See why here.) So, let’s move onto the next step.

Check 3: Check the Source

What is the textbook’s worldview starting point? It’s clearly not God’s Word, but evolutionary naturalism. Our starting points affect which assumptions we use to interpret observational science, which will be worth remembering for Check 6.

Check 4: Check the Definitions

As in other arguments involving natural selection, a keyword to watch in this message is evolution. The textbook suggests bacterial resistance is evidence for “evolution” in the sense that one kind of living thing can supposedly evolve into another. But what we actually observe is “evolution” in the sense of variation within the Staphylococcus kind, due to mechanisms like mutation and natural selection, which don’t produce the types of changes required for between-kind evolution. So, this could be considered a bait-and-switch fallacy.

Check 5: Check for Propaganda

Why might the fallacious claim that bacterial resistance evinces evolution seem persuasive? One factor may be how often we hear this message repeated by multiple sources, ranging from textbooks to government reports. Psychological research shows that repeated messages tend to sound truer, even if we know they’re false.8

As another example of propaganda, the bacterial resistance quote from the “Dangers of Creationism in Education” report leverages the persuasive power of emotion. By a bait-and-switch on the word evolution, the report incorrectly conflates “denying evolution” (in the between-kinds sense of evolution, which cannot be observed) with ignoring observational science—and, therefore, endangering society. This creates a fear appeal. Notice also, the word “denying” presupposes that evolution is true, caricaturing the questioning of evolution as willful ignorance—if not utter lunacy.

Check 6: Check the Interpretations

Now, the real fun begins. Remember that when you encounter a textbook example of “evolution,” there’s often more to the story than you’re hearing. What you’re hearing is likely the most polished presentation of an evolutionary interpretation for the relevant facts. Let’s dig deeper into observational science of drug-resistant bacteria, uncover some parts of the story the textbook didn’t mention, and find out whether drug resistance is really the evolutionary “evidence” it’s interpreted to be.

As it turns out, bacteria can become drug resistant a number of different ways. For instance, mutations can cause bacteria to lose control over how much protein they make from certain genes, so they overproduce proteins that destroy antibiotics or help remove drugs from the cell. That’s what my textbook didn’t say about the penicillin-resistant bacteria: they already had the genetic information to make penicillinase; they just lost control over how much they produced.9

In other cases, mutations may cause defects to proteins which otherwise let antibiotics enter or bind to bacteria. That’s what happened with the methicillin-resistant strains my textbook mentioned. Normally, methicillin binds to a protein called PBP2, which the bacteria require to build their cell wall. But many resistant bacteria have a mutated version of this protein called PBP2a, which are deformed so that the antibiotic can’t bind. Like any mutation, this isn’t the creation of new genetic information so much as the corruption of existing genetic information. And evolutionists are still left to explain where that information originated.10

Another point textbooks don’t always mention is that while drug resistance could be considered a beneficial mutation for bacteria exposed to antibiotics, those mutations often come at a price. Frequently, such mutations involve some loss of function or efficiency. For instance, normal PBP2 proteins in S. aureus can link together both sugars and peptides for building cell walls. When methicillin binds to PBP2s, they can no longer link peptides together. The mutant proteins, which can’t bind methicillin, can link peptides, but not sugars. So, the cell needs both mutant and normal proteins working together to maintain the cell wall when exposed to methicillin.11 In the same way, many “superbugs” with resistance to multiple antibiotics have so many mutational defects that they can’t outcompete normal bacteria in the wild.

If that weren’t enough, something else which isn’t often clear from textbooks is that multiple studies have identified drug resistance in ancient bacteria, as microbes have been producing antibiotics long before modern medicine. For instance, a study on antibiotic-resistant bacterial DNA in supposedly 30,0000-year-old Canadian permafrost revealed what researchers called “conservation of gene sequence and synteny with modern resistance clusters in the clinic as well as protein function and structure.”12 In other words, the supposedly 30,000-year-old bacteria looked and acted like modern antibiotic-resistant bacteria, right down to their DNA and proteins.

Tackling Textbook Tales

In the end, do humans’ observations of microbes really suggest that humans evolved from . . . microbes? No, that’s a misconception which a little biblical, critical thinking can help you “resist.” The closer you look at bacterial resistance, the more you can discover that—far from being textbook evidence for evolution—the observational science is consistent with a biblical worldview.

For more on how to think critically about any faith-challenging message, stay tuned for future blog articles and my new video series, CT (Critical Thinking) Scan, available now on the AiG Canada YouTube channel and the AiG Canada Facebook page.

Footnotes

  1. Parliamentary Assembly of the Council of Europe, Committee on Culture, Science and Education, “Resolution 1580. The dangers of creationism in education.” October 4, 2007, http://assembly.coe.int/nw/xml/XRef/Xref-XML2HTML-EN.asp?fileid=17592&lang=en.
  2. Anne Brasseur (rapporteur), Parliamentary Assembly of the Council of Europe. Committee on Culture, Science and Education, “The dangers of creationism in education” (Report). September 17, 2007. https://assembly.coe.int/nw/xml/XRef/X2H-Xref-ViewHTML.asp?FileID=11751&lang=EN.
  3. Reece, et al., “Descent with Modification: A Darwinian View of Life,” In G. Bennett, L. Rahn, D. Kamo, E. Bush, & S. Bindernagel (Eds.), Campbell biology, Canadian ed. (Upper Saddle River, NJ: Pearson Education, 2012), 484–501.
  4. Reece, “Descent,” 494.
  5. Is it circular reasoning for Christians to compare messages against Scripture? No: to find out why not, see Critical Thinking Scan Episodes 36-37 and the associated resources.
  6. Some would argue that given enough time, the mechanisms underlying such changes within kinds of living things (especially mutation and natural selection) would eventually cause changes between kinds of living things. For information on some of the issues with this assumption, see Mutations, Is Natural Selection the Same Thing as Evolution? and Information Theory.
  7. Genesis 1:31.
  8. E.g., Christian Unkelbach, “Reversing the truth effect: Learning the interpretation of processing fluency in judgments of truth,’ Journal of Experimental Psychology: Learning, Memory, and Cognition 33, no. 1 (2007): 219.
  9. See Has Evolution Really Been Observed?.
  10. Bacteria can also pick up genes from other microorganisms and their environment through a few different mechanisms. But again, even though the gene might be new to that bacterium, it’s not a completely novel gene; it had already been existing somewhere. And it’s the origin of functional new genetic information that would be required for one kind of organism, like bacteria, to eventually evolve into completely different organisms, like humans.
  11. Pinho, Mariana G., Hermínia de Lencastre, and Alexander Tomasz, "An acquired and a native penicillin-binding protein cooperate in building the cell wall of drug-resistant staphylococci," Proceedings of the National Academy of Sciences 98, no. 19 (2001): 10886-10891.
  12. Julie Perry, Nicholas Waglechner, and Gerard Wright, "The prehistory of antibiotic resistance," Cold Spring Harbor Perspectives in Medicine 6, no. 6 (2016): a025197.

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