Pharmaceutical Metabolites in Wastewater

This took less than 30 seconds to find.

The increased prevalence of antibiotic resistance is an outcome of evolution. Any population of organisms, bacteria included, naturally includes variants with unusual traits--in this case, the ability to withstand an antibiotic's attack on a microbe. When a person takes an antibiotic, the drug kills the defenseless bacteria, leaving behind--or "selecting," in biological terms--those that can resist it. These renegade bacteria then multiply, increasing their numbers a millionfold in a day, becoming the predominant microorganism.

The antibiotic does not technically cause the resistance, but allows it to happen by creating a situation where an already existing variant can flourish. "Whenever antibiotics are used, there is selective pressure for resistance to occur. It builds upon itself. More and more organisms develop resistance to more and more drugs," says Joe Cranston, Ph.D., director of the department of drug policy and standards at the American Medical Association in Chicago.

The antibiotics are not causing any sort of mutation in the bacteria, these bacteria already exist. The antibiotics make it easier for them to compete and flourish. This, however, is not the case in many underdeveloped nations. In these areas, when a person contracts a strain of resistant bacteria, they can pass it on to their entire village quite easily. So really, it is the MISuse of antibiotics, not the USE of antibiotics themselves. Also, metabolites of drugs will not allow for selection of resistant bacteria.

~MFP

Originally posted by bsl4doc
The antibiotics are not causing any sort of mutation in the bacteria, these bacteria already exist. The antibiotics make it easier for them to compete and flourish. This, however, is not the case in many underdeveloped nations. In these areas, when a person contracts a strain of resistant bacteria, they can pass it on to their entire village quite easily. So really, it is the MISuse of antibiotics, not the USE of antibiotics themselves. Also, metabolites of drugs will not allow for selection of resistant bacteria.

bsl4doc

Nice switch and bait, but that was NOT your initial point. You said:

Originally posted by bsl4doc
I don't think this issue relates much, if at all, to the emergence of antibiotic resistance bacteria.

Clearly, that is wrong.

Then you say:

Originally posted by bsl4doc
There are many studies, quite a few published by the CDC from other organizations, about methycillin resistant and tetracyclin resistant bacteria in southeast Asia and parts of Africa. Now, if the drugs in waste water were causing an antibiotic resistance in bacteria, wouldn't it seem like the strains would show up in areas with the most exposure to these drugs, not in areas where little to no exposure is given?

How did you arrive at that conclusion? Indeed, this research article indicates:

Prior to the mid-1950s, the majority of commensal and pathogenic bacteria were susceptible to tetracyclines (144), as illustrated by the finding that among 433 different members of the Enterobacteriaceae collected between 1917 and 1954, only 2% were resistant to tetracycline (106). Studies of naturally occurring environmental bacteria, representative of populations existing before the widespread use of tetracyclines by humans (52), also support the view that the emergence of resistance is a relatively modern event that has followed the introduction of these agents for clinical, veterinary, and agricultural use.

Tetracycline Antibiotics: Mode of Action, Applications, Molecular Biology, and Epidemiology of Bacterial Resistance

And this article, specifically concerning the emergence of antibiotic resistance in Africa, states:

Studies from around the world have shown that between 40 and over 90% of antibiotic prescriptions are unnecessary. In many parts of Africa, where antibiotics are commonly available from unsanctioned providers, it will be worth educating the general populace about the consequences of irrational antibiotic resistance. Unsanctioned providers often reach out to people with limited access to orthodox health care, and are commonly not trained to diagnose infections or correctly prescribe appropriate doses. They however serve as an unofficial outlet for many antibiotics, often capsules and tablets of cheaper antimicrobials, but are not limited to these. For example, Becker et al [25] recently described the inappropriate distribution of injectable antibiotics, including second- and third-line drugs such as oxacillin and third-generation cephalosporins, medicines that should be conserved for managing resistant infections.

Antibiotic Resistance in Africa

Sounds like antibiotics are rather ubiquitous there, don't you think?

Originally posted by bsl4doc
The antibiotics are not causing any sort of mutation in the bacteria, these bacteria already exist. The antibiotics make it easier for them to compete and flourish.

What manner of voodoo is it to point out that antibiotics are not the "technical" cause of mutation? I don't recall anyone saying otherwise. But their fairly consistent presence is certainly the proximate cause of bacterial resistance.

Then you say:

Originally posted by bsl4doc
This, however, is not the case in many underdeveloped nations. In these areas, when a person contracts a strain of resistant bacteria, they can pass it on to their entire village quite easily.

Huh? Aren't you attempting to tell the tale by starting from the middle???? Once again, you omit the conditions that led to the emergence of such resistant strains of bacteria. Once these resistant strains predominate, of course they can then be easily passed to others.

Originally posted by bsl4doc
So really, it is the MISuse of antibiotics, not the USE of antibiotics themselves.

I'm sorry. Were you under the impression that someone in this thread was arguing against all use of antibiotics?

Originally posted by bsl4doc
Also, metabolites of drugs will not allow for selection of resistant bacteria.

The University at Buffalo appears to disagree with you...

...antibiotics and their metabolites can significantly increase antibiotic resistance in the population...

Metabolites of pharmaceuticals identified in wastewater

You will note that the above quote is from the actual press release issued by the University at Buffalo.

Here's another article identifying metabolites as a co-conspirator of bacterial resistance:

From an environmental standpoint, the discharge of antibiotics and their metabolites in farm wastes could create a reservoir of resistant microorganisms in the environment.

Human Health Impact and Regulatory Issues Involving Antimicrobial Resistance in the Food Animal Production Environment

Penso che la studentessa deve studiare un po di piu', no?


[edit on 23-3-2006 by loam]

Loam, you're missing my point. I was pointing out the fact that, contrary to a few others, the drugs are not the CAUSE of the drug resistance. Many resistant strains have been observed in areas with little contact with antibiotics. You're right, I concede on the metabolite point. I was making an assumption based on the idea that perhaps a drug metabolite makes enough of a conformational change so as to inactive epitopic ability. It appears I made an incorrect assumption, and I admit it.

My other points, however, stand. These resistant strains are not emerging due to antibiotics any more than a new flu emerges each year. Bacteria are opportunistic organisms. Just because suddenly an area has an epidemic of antibiotic resistant bacteria does not mean it wasn't there in the background already. It simply did not have the ability to create a flora due to competition with stronger bacteria without these resistances.

~MFP

Fair enough. On that technical aspect, then, we agree.

EDIT: Love the avatar btw.

[edit on 23-3-2006 by loam]

what is it doing to the environment???

well, guys, ya know how they are saying that that little chromosome that makes you guys is deteriorating and will soon be gone?? thus no more guys...
our pollution is speeding up the process.

well, forget about the antibiotics, the hormones are what you should be worried about!! before you become like the fish and start producing eggs, that then become fertilized and you start having babies!!

Male Fish Producing Eggs in Potomac River

news.nationalgeographic.com...

they've also found significant changes in alligators, the eggs of birds, and I forget what else....

in other words, we are messing up the environment.....and it is having some pretty bad side effects. if it is affecting birds, gators, fish and frogs, it's affecting us also..

Dawnstar, the Y chromosome has been loding genes for milennia. Also, the Y chromosome has been found to create palindrome genes within itself, so it is repairing at about the same rate it is degrading. This has nothing to do with pollution.

~MFP

I belive dawnstar is pointing to the mutations already been found in sea water organism from hormones, in the instances of fish found in some areas the male sex are changing.

That is on fish but how long it will take to affect the human species or start with sea water mammals.

[edit on 24-3-2006 by marg6043]

Good grief BSdoc - Are you saying that contaminants and pollution introduced into the environment do not have any impact on microbes? That microbes do not adapt to the environment and evolve in an environmental context?

...Prove it. Please. With references.

And then I'll get out my Ouiji board and tell Darwin.

Good grief BSdoc - Are you saying that contaminants and pollution introduced into the environment do not have any impact on microbes? That microbes do not adapt to the environment and evolve in an environmental context?

...Prove it. Please. With references.

And then I'll get out my Ouiji board and tell Darwin.

No, that is not what I'm saying. Please take your spin goggles off and rered my post.

What I AM saying is that these microbes are not becoming resistant due to antibiotics. The true problem is that antibiotic resistant bacteria survive the "culling of the weak" caused by the introduction of an antibiotic, and are then free to thrive in an environment full of nutrients.

This is a common practice in undergraduate genetics and microbiology class rooms. Take, for instance, a luria broth tube containing two strains of E. coli. Strain I is wild-type, strain II is ampicillin resistant. Culture a 5mL sample of the tube onto two plates, one a normal nutrient plate and the other a nutrient plate with ampicillin. Now, notice the difference. On plate one, both species will grow, although antibiotic resistant strains tend to be weaker, harder to grow, and smaller in colony size. However, on plate two, there are only resistant colonies, and they are larger and heathier than the corresponding resistant colonies on plate one. Is this because the bacteria on plate two has mutated due to the presence of an antibiotic and is now thriving? NO, it is because the non-resistant bacteria have died, leaving the resistant bacteria to thrive in a nutrient rich environment. THIS is the risk of misusing antibiotics, not some random mutation but selective culturing in our sewer systems and water supplies.

Capisce?

~MFP

Hmmm.

Most researchers claim they don't really know why bacteria are becoming resistant to antibiotics - but you know definitively?

Overuse, misuse and abuse usually are flagged as causal factors - but still, there is an element of mystery. For example:

"The experts investigating the outbreak say the bacterium appears to have mutated into a highly contagious and lethal strain – and they don't know why. ...
"Something happened 18 to 24 months ago, ...Now it seems any antibiotic can bring on the disease."

Your comments?


.

Soficrow -

There is a vast difference between antibiotic resistance and a bacteria's ability to infect changing. There are most certainly mutations which can and do occur in bacteria which may cause the bacteria, or virus for that matter, to become more contagious or easier to communicate. This his little to do with antibiotic resistance. The ability of our doctors to combat the disease, THAT has to do with antibiotic resistance. However, in the article you presented, it doesn't seem they are referring to the bacteria's ability to resist antibiotics so much as its ability to metabolize it and use it as an energy source. They mention that certain antibiotics "bring on the infection". In my opinion, this seems like it would occur because a patient who already has a low level exopsure to C. difficile takes drug A for a different invading bacteria. This drug wipes out most other bacteria infecting them at the time, but C. difficile can use it as food, thus giving the bacteria a huge new energy source and a lot of room to grow due to the other bacteria's death.

C. difficile is definitely a threat, but it is not due to antibiotic RESISTANCE, so much as antibiotic METABOLISM.

Very interesting find, by the way. I liked that article.

~MFP

[edit on 3/24/2006 by bsl4doc]