The kicker—if the doctor would stop to think about it, it should jump out as unintuitive – it would take some serious changes inside the lung to make an anaerobic infection – an infection of bacteria that thrive in areas with no oxygen. In reality it takes frequent aspirations over a long period of time to block off an area of the lungs.
The normal flora of the skin, mouth, and upper respiratory tract contains anaerobic bacteria; this alone should be sufficient to disprove overly simplistic “But there’s oxygen, you can’t have anaerobic bacteria there!” theories. Anaerobes are actually more common than aerobes in the mucus membranes of the mouth and URT and in fact outnumber aerobes in saliva about 10:1. According to The Anaerobic Microflora of the Human Body:
It is not surprising that anaerobes are present in large numbers in the flora of the intestinal and geintourinary tracts because oxygen concentrations are low in these regions. However, it appears unusual that they are also prominent members of the flora of the skin, mouth, nose, and throat—regions that are continuously exposed to air. The presence of anaerobes in these areas is explained first by the activity of the aerobic and facultatively anaerobic components of the flora that reside in association with the anaerobes and consume oxygen in their metabolism and second, by the colonization of anaerobes of microhabitats protected from air.
I think the moral of this story all people, be they doctors or kindergarteners, don’t usually check facts they’re taught, especially when being taught by an authoritative teacher.
Okay, here’s what actually happened. In the 1970s and 1980s, a lot of people worked really hard studying the microbiology of aspiration pneumonia and all of them found lots of anaerobes. In the late 1990s, some other people, especially a guy named Paul Marik, tried the same thing using more modern techniques and found very few anaerobes. They concluded that the old studies had been wrong.
Some other people objected that anaerobes are really hard to detect and that maybe Marik and his supporters had just screwed up and not been able to find them even though they were there. This seems to be the view of Rene et al, who claimed to have repeated Marik’s experiments using better technique and found lots of anaerobes just like the old theories would have predicted. It was then counterclaimed that Marik’s experiment had been unusually rigorous and well-conducted, plus it was also easy to screw up the other way—that sometimes samples might have been contaminated by anaerobes in the upper respiratory tract that weren’t responsible for the pneumonia at all. Everyone had a nice big fight about it which as far as I know still has not been fully resolved. UpToDate, which I tend to trust on this sort of thing, pushes the pro-anaerobe line, but emedicine, which is also pretty good, pushes the anti-anaerobe line. I do get the feeling the anti-anaerobe people now have the upper hand.
The rationalist thing to do would be to let the microbiologists fight it out among themselves and just study which antibiotics are most effective against aspiration pneumonia. The answer to that is very complicated, but the oversimplified answer as given by UpToDate is clindamycin, an antibiotic known for its efficacy against anaerobes, which seems to maybe suggest there was some kind of anaerobic component after all—but I am reading between the lines here on a subject I’m not really qualified to read-between-lines on and am probably completely wrong about this.
I agree that many doctors don’t know anything about this (I hadn’t heard of it until you brought it up and I checked the literature). The average doctor just checks every so often to see what antibiotic is recommended for aspiration pneumonia and then prescribes that one. As far as I know the antibiotic recommendations are still correct. This seems like a pretty efficient system, given how many things doctors have to know.
Anyway, as far as I can tell the real moral of this story is that medicine is really really hard and complicated and, like all science, often changes as technology improves and better experiments become possible. This is a less fun narrative than “Doctors are incredibly stupid and just by knowing about this one study I can totally outdo all of them” (YES, EVERYONE ON LESS WRONG, I AM TALKING ABOUT YOU) but fun narratives are wrong suspiciously often and this one is no exception.
Woah, nice, thanks for all that research! Yeah, it looks pretty much just how you described it. So, my statement, “no research backs it up” was wrong—there was research in the 70s and 80s that DID indicate it, so there WAS evidence. Thus, this is a case of “Old ideas in the process of getting overturned… maybe” and not “people doing it without science backing it up”.
I don’t have access to UpToDate here (because they recently skyrocketed their prices so my school is switching), so I only read emedicine.
EDIT:
I can only read the abstracts, and nothing from the 70s article, so this input is limited. That said, the 80s article seemed to look at all aspiration pneumonias (most of which was are caused by chronic aspiration), while my professor’s point was specifically about one-time aspiration (i.e. aspirating vomit). I did not make that distinction clear in my OP.
So, you’re right, though I wanted to defend my professor, because I think his point might still stand, though my post did not present the full story. I’d look more into the research, but I probably won’t find the time. Yvain’s a real trooper for wading through all those articles.
I’ve read a decent number of your posts, and it seems a bit out of character for you to generalize so heavily, and use all caps to describe everyone on LW as having a sentiment similar to, “Doctors are incredibly stupid and just by knowing about this one study I can totally outdo all of them.”
I know you don’t really mean it literally, but it may be worth pointing out that that sort of thing is just another one of those epistemically hazardous and unhygienic habits that should be done away with.
it seems a bit out of character for you to generalize so heavily
Seems to me that Yvain is slightly fed up with those on the site who display the LW superiority attitude (I also complain about it on occasion, and so do others). The generalization and all caps probably indicate a certain amount of bitter sarcasm.
Yeah. Slightly fed up is too fed up. It’s never useful to be fed up, as far as I’ve ever seen. I’ve read a decent number of Yvain’s posts, and he’s always come off as rather immune to getting ‘fed up’ or ‘annoyed’ or anything, so I thought it was sort of out of character, and not in a good way.
“Doctors are incredibly stupid and just by knowing about this one study I can totally outdo all of them”
That is a common attitude here, but I don’t see how this post reflects it. Rather, the author fell prey to same thing they were highlighting, more or less.
The irony of that fact certainly wasn’t lost on me. :) I though about checking up on the prof, but like I said, if I did that every time I’d never graduate.
But yes, thanks for saying that. I’m not often one to doctor-bash; my hubris often comes from being a “Future Doctor” rather “being a Rationalist.”
Lorber B, Swenson RM. Bacteriology of aspiration pneumonia. A prospective study of community- and hospital-acquired cases Ann Intern Med. 1974 Sep;81(3):329-31.
Brook I, Finegold SM. Bacteriology of Aspiration Pneumonia In Children, Pediatrics. 1980 Jun;65(6):1115-20.
Finegold SM. Aspiration Pneumonia Rev Infect Dis. 1991 Jul-Aug;13 Suppl 9:S737-42.
Bartlett JG. Anaerobic bacterial infections of the lung and pleural space Clin Infect Dis. 1993;16 Suppl 4:S248.
Yamashita Y et al. Anaerobic respiratory infection—evaluation of methods of obtaining specimens. Kansenshogaku Zasshi. 1994;68(5):631.
El-Solh AA et al. Microbiology of severe aspiration pneumonia in institutionalized elderly. Am J Respir Crit Care Med. 2003 Jun 15;167(12):1650-4. Epub 2003 Apr 10.
The normal flora of the skin, mouth, and upper respiratory tract contains anaerobic bacteria; this alone should be sufficient to disprove overly simplistic “But there’s oxygen, you can’t have anaerobic bacteria there!” theories. Anaerobes are actually more common than aerobes in the mucus membranes of the mouth and URT and in fact outnumber aerobes in saliva about 10:1. According to The Anaerobic Microflora of the Human Body:
It is not surprising that anaerobes are present in large numbers in the flora of the intestinal and geintourinary tracts because oxygen concentrations are low in these regions. However, it appears unusual that they are also prominent members of the flora of the skin, mouth, nose, and throat—regions that are continuously exposed to air. The presence of anaerobes in these areas is explained first by the activity of the aerobic and facultatively anaerobic components of the flora that reside in association with the anaerobes and consume oxygen in their metabolism and second, by the colonization of anaerobes of microhabitats protected from air.
Okay, here’s what actually happened. In the 1970s and 1980s, a lot of people worked really hard studying the microbiology of aspiration pneumonia and all of them found lots of anaerobes. In the late 1990s, some other people, especially a guy named Paul Marik, tried the same thing using more modern techniques and found very few anaerobes. They concluded that the old studies had been wrong.
Some other people objected that anaerobes are really hard to detect and that maybe Marik and his supporters had just screwed up and not been able to find them even though they were there. This seems to be the view of Rene et al, who claimed to have repeated Marik’s experiments using better technique and found lots of anaerobes just like the old theories would have predicted. It was then counterclaimed that Marik’s experiment had been unusually rigorous and well-conducted, plus it was also easy to screw up the other way—that sometimes samples might have been contaminated by anaerobes in the upper respiratory tract that weren’t responsible for the pneumonia at all. Everyone had a nice big fight about it which as far as I know still has not been fully resolved. UpToDate, which I tend to trust on this sort of thing, pushes the pro-anaerobe line, but emedicine, which is also pretty good, pushes the anti-anaerobe line. I do get the feeling the anti-anaerobe people now have the upper hand.
The rationalist thing to do would be to let the microbiologists fight it out among themselves and just study which antibiotics are most effective against aspiration pneumonia. The answer to that is very complicated, but the oversimplified answer as given by UpToDate is clindamycin, an antibiotic known for its efficacy against anaerobes, which seems to maybe suggest there was some kind of anaerobic component after all—but I am reading between the lines here on a subject I’m not really qualified to read-between-lines on and am probably completely wrong about this.
I agree that many doctors don’t know anything about this (I hadn’t heard of it until you brought it up and I checked the literature). The average doctor just checks every so often to see what antibiotic is recommended for aspiration pneumonia and then prescribes that one. As far as I know the antibiotic recommendations are still correct. This seems like a pretty efficient system, given how many things doctors have to know.
Anyway, as far as I can tell the real moral of this story is that medicine is really really hard and complicated and, like all science, often changes as technology improves and better experiments become possible. This is a less fun narrative than “Doctors are incredibly stupid and just by knowing about this one study I can totally outdo all of them” (YES, EVERYONE ON LESS WRONG, I AM TALKING ABOUT YOU) but fun narratives are wrong suspiciously often and this one is no exception.
Woah, nice, thanks for all that research! Yeah, it looks pretty much just how you described it. So, my statement, “no research backs it up” was wrong—there was research in the 70s and 80s that DID indicate it, so there WAS evidence. Thus, this is a case of “Old ideas in the process of getting overturned… maybe” and not “people doing it without science backing it up”.
I don’t have access to UpToDate here (because they recently skyrocketed their prices so my school is switching), so I only read emedicine.
EDIT: I can only read the abstracts, and nothing from the 70s article, so this input is limited. That said, the 80s article seemed to look at all aspiration pneumonias (most of which was are caused by chronic aspiration), while my professor’s point was specifically about one-time aspiration (i.e. aspirating vomit). I did not make that distinction clear in my OP. So, you’re right, though I wanted to defend my professor, because I think his point might still stand, though my post did not present the full story. I’d look more into the research, but I probably won’t find the time. Yvain’s a real trooper for wading through all those articles.
I’ve read a decent number of your posts, and it seems a bit out of character for you to generalize so heavily, and use all caps to describe everyone on LW as having a sentiment similar to, “Doctors are incredibly stupid and just by knowing about this one study I can totally outdo all of them.”
I know you don’t really mean it literally, but it may be worth pointing out that that sort of thing is just another one of those epistemically hazardous and unhygienic habits that should be done away with.
Seems to me that Yvain is slightly fed up with those on the site who display the LW superiority attitude (I also complain about it on occasion, and so do others). The generalization and all caps probably indicate a certain amount of bitter sarcasm.
Yeah. Slightly fed up is too fed up. It’s never useful to be fed up, as far as I’ve ever seen. I’ve read a decent number of Yvain’s posts, and he’s always come off as rather immune to getting ‘fed up’ or ‘annoyed’ or anything, so I thought it was sort of out of character, and not in a good way.
Also an easy mistake to make when not differentiating between facultative anaerobes and obligate anaerobes.
That is a common attitude here, but I don’t see how this post reflects it. Rather, the author fell prey to same thing they were highlighting, more or less.
The irony of that fact certainly wasn’t lost on me. :) I though about checking up on the prof, but like I said, if I did that every time I’d never graduate.
But yes, thanks for saying that. I’m not often one to doctor-bash; my hubris often comes from being a “Future Doctor” rather “being a Rationalist.”