Common equivalent to antibiotic ?

[Externet]

Someone I know mixes eritromycin with clear epoxy and paints the hull of his boat, a kilo in 10 litres.

Says lasts over 10 years, with nothing attaching/growing on it.

Any compound that would have the same effect ? At my location, antibiotics are not sold freely.

 

Don't know if 'equivalent' can be twisted towards some kind of poison that could be a marine life permanent danger. The confinement status of a non decaying killer/contaminant product in epoxy can be arguable, I understand.

[CharonY]

Sounds odd. While I do not know precisely the half-life of erithromycine I would have expected it to be something in the area of weeks at most, especially under these conditions. Also, if it prevents something from growing than it is likely that is due to the inheritent toxic properties of erithromycine rather than antibacterial action as afaik bacterial biofilm are not necessarily the main component of biofouling in boats.

However there are a number of repellants in development, at least one of them relying on small geometric structures that prevent settlement by algae, barnacles etc. rather by using a toxin.

[Externet]

Thanks.

The explanation I received is that barnacles and algae footings/rootings do erode the epoxy surface to secure attachment, and is when they become in contact with the until-then-preserved, embedded, still active antibiotic.

 

And done that way because the cost of currently available commercial anti-fouling coatings is too high for the service time they provide. The light, poor attachment of algae that occurs even with this treatment just washes away by itself with boat motion.

Edited March 9, 2009 by Externet
eliminated duplicate

[CharonY]

Hmm interesting if that works. But essentially you could use any pesticide or other toxic substance then. It does not have to be an antibiotic as, well, barnacles and algae are obviously no bacteria. Just a different notion. Has anyone tried painting just with epoxy but no ABs?

[DrDNA]

Erythromycin is generally used to treat Strep Throat, Mastitis in dairy cattle and to kill blue-green algae (cyanobacteria) in aquariums.

Eryrhomycin works by interfering with the 50S ribosome; which is specific to bacteria and cyanobacteria.

Also, a major cause of fouling on boat hulls is a result of "seaweed" type algae, which should not be effected by Erythromycin.

 

So, broad range toxic substances like copper and tin are usually in antifouling paints.

 

Consequently, it seemed implausible to me at first and I even almost finished writing a quite lengthy response about the intimate details of why this would not work.

 

 

Then to humor myself, I decided to do a quick search and low and behold, I saw this patent:

 

 

United States Patent 5143545

 

>>>>>>>

 

During a field study we found microorganisms attached to the hull of a Naval ship that produced an inordinate amount of a lipopolysaccharide (LPS), a slimy material. This slimy material is quite commonly produced by marine organisms classified as gram negative spirillum or bacteria. We isolated a representative culture of the microbial population and, based on morphology and biochemical characteristics, determined that these slime-producing microorganisms were of the genus Oceanospirillum, a genus which is indigenous to almost all the world's harbors and estuaries.

 

Tests were made to determine the sensitivity of this Oceanospirillum species to various non-photolytic antibiotics having low solubility in water, using a sensitivity disc method similar to the Kirby-Bauer standardized single-disc method described in Bauer, Kirby, Sherris and Turck, Am. J. Clinical Pathology, 45: 493, 1966. Agar plates were prepared by pouring 10 ml of a known, commercially available, marine agar, Bacto Marine Agar 2216, onto each plate. After the plates solidified, 0.1 ml of a 24 hour culture of the slime-producing Oceanospirillum species was spread evenly over the surface of each plate, and allowed to dry. Small filter pads containing selected antibiotics were dropped on the surface of the agar of each plate, and the plates incubated for 24 hours at 20° C. The plates were then examined and zones of inhibition (an indicator of sensitivity to the antibiotic) were measured with a micrometer. The results of these tests are:

______________________________________

ANTIBIOTIC CONCENTRATION INHIBITION (mm.)

______________________________________

 

Erythromycin

15 micrograms 21.5

Chlortetracycline

30 micrograms 0

Neomycin 30 micrograms 11.5

Streptomycin

10 micrograms 14.5

Chloramphenicol

20 micrograms 18.9

Penicillin 10 units 0

______________________________________

 

Chloramphenicol was selected, from among the tested antibiotics having an inhibitory effect on this Oceanospirillum species, for further testing as an additive to a copper-based antifouling marine paint. Chloramphenicol has a low solubility in water of 2.5 mg/ml, is non-photolytic, dissolves readily in the organic volatile substances in paint formulations, and is stable in solvents associated with paint manufacturing.

>>>>

 

 

So, It seems entirely plausible.

You might try Chloramphenicol. According to the patent, it should work better and may be cheaper.

---

Merged post follows:

Consecutive posts merged

PS:;

CharonY, epoxy-type resins are often used on boat hulls.

Without the addition of antifouling agents (like tin or copper or other toxic agents), the hulls foul rather quickly and must be scrapped and repainted on a nore frequent basis.

Edited March 9, 2009 by DrDNA
Consecutive posts merged.

[CharonY]

Actually from the little information I got from a talk the main aspects of biofouling on boats is not caused by bacteria. Though they may be the first to settle. However, their presence (that is what I meant with biofilm in my first post) is not really necessary for all the others (algae, barnacles, etc.) to settle (I am not too sure about the subject myself, and the talker was a material scientist).

However, if the erithromycine prevents settlement of algae and barnacles I would assume that it is due to the toxic properties of the AB. You have to remember that while the primary targets of ABs are, obviously, bacteria, basically all of them are also relatively toxic to other organism, albeit due to unspecific effects. I think I recall a LD50 values for some fishes for Erithromycin of around 500 mg/kg.

[Externet]

Thanks, fellows. Seems there is some interesting truth in the technique.

 

Would the use of borax instead of an antibiotic produce similar results ?

 

What other compounds you suggest that embedded in paint or epoxy will prevent the growth/attachment of marine life to a hull; without contaminating the sea - I mean, would be effective when the organism erodes the paint and reaches the toxin; but the toxin would not be washed itself by the sea.

 

Miguel