Choosing the right antibiotic ?
Posted: Thu Jul 14, 2011 11:00 am
How do we choose which antibiotics to give our koi ?
We all know that our ponds teem with life of all sorts especially bacteria. I started thinking that if we knew what bacteria where in our ponds and which antibiotics they were sensitive to, whenever we had a bacterial infection problem we could make a more informed guess as to what antibiotics to use. This was based on; I think the reasonable assumption that, the bugs our fish are swimming in are the most likely ones to be causing our problems.
So I set up an experiment. I took water samples from my ponds and growing on / QT tank and samples from any pond keeper (thank you to several people on this site) that would let me have some and cultured them for bacteria and fungi (but that is another story). I obtained samples from 11 ponds in total.
The picture that emerged was that all ponds tested had (on a scale of 1 to 5 based on colony counts) a score of 3. The worst one was my heated (25 deg C) QT pond which I scored as the worst i.e. a 5!
The organisms were remarkably consistent between ponds but even more surprising was the marked inconsistency in the sensitivity of the different ponds’ bacteria to antibiotics. Looking back I realise I should have asked what had been the use of antibiotics in the previous year, did they PP their pond or use products like Chloramine T* or Vikron*.The problem is that it is very hard to get an honest answer to these questions, with the exception, of course of members of this forum.
Based on the data from the 11 ponds I made the following observations;
1) There is marked similarity between the ponds looked at in terms of bacteria and colony count. The most common organisms isolated from the samples were;
a. Aeromonas species mainly salmonicidia
b. Pseudomonas species
c. Lactobacilli species
d. Strep species mainly strep faecalis
2) There was a marked dissimilarity between the sensitivity of the bacteria grown to different antibiotics. This may reflect previous antibiotic use but this cannot, in this experiment, be proven (any volunteer ponds for my next experiment prepared to tell me what they treat their fish with and what do they treat their ponds with i.e. PP?)
3) The most effective antibiotic seemed to be Amikacin* but several ponds had resistant strains of Pseudomonas species which are known to be opportunistic pathogens. Most of these strains were however still sensitive to combination therapy i.e. Amikacin plus Ampicillin. Baytril* seems, from this small study, to still to be a useful agent but did not cover quiet the same number of bugs as Amikacin although this study was too small to draw any firm conclusions.
I am now looking at some more ponds to get a bigger sample and follow one or two ponds throughout a year preferably one or two heated and one or two not heated.
I hope this helps our thinking when choosing antibiotics
Peter Trademark*
We all know that our ponds teem with life of all sorts especially bacteria. I started thinking that if we knew what bacteria where in our ponds and which antibiotics they were sensitive to, whenever we had a bacterial infection problem we could make a more informed guess as to what antibiotics to use. This was based on; I think the reasonable assumption that, the bugs our fish are swimming in are the most likely ones to be causing our problems.
So I set up an experiment. I took water samples from my ponds and growing on / QT tank and samples from any pond keeper (thank you to several people on this site) that would let me have some and cultured them for bacteria and fungi (but that is another story). I obtained samples from 11 ponds in total.
The picture that emerged was that all ponds tested had (on a scale of 1 to 5 based on colony counts) a score of 3. The worst one was my heated (25 deg C) QT pond which I scored as the worst i.e. a 5!
The organisms were remarkably consistent between ponds but even more surprising was the marked inconsistency in the sensitivity of the different ponds’ bacteria to antibiotics. Looking back I realise I should have asked what had been the use of antibiotics in the previous year, did they PP their pond or use products like Chloramine T* or Vikron*.The problem is that it is very hard to get an honest answer to these questions, with the exception, of course of members of this forum.
Based on the data from the 11 ponds I made the following observations;
1) There is marked similarity between the ponds looked at in terms of bacteria and colony count. The most common organisms isolated from the samples were;
a. Aeromonas species mainly salmonicidia
b. Pseudomonas species
c. Lactobacilli species
d. Strep species mainly strep faecalis
2) There was a marked dissimilarity between the sensitivity of the bacteria grown to different antibiotics. This may reflect previous antibiotic use but this cannot, in this experiment, be proven (any volunteer ponds for my next experiment prepared to tell me what they treat their fish with and what do they treat their ponds with i.e. PP?)
3) The most effective antibiotic seemed to be Amikacin* but several ponds had resistant strains of Pseudomonas species which are known to be opportunistic pathogens. Most of these strains were however still sensitive to combination therapy i.e. Amikacin plus Ampicillin. Baytril* seems, from this small study, to still to be a useful agent but did not cover quiet the same number of bugs as Amikacin although this study was too small to draw any firm conclusions.
I am now looking at some more ponds to get a bigger sample and follow one or two ponds throughout a year preferably one or two heated and one or two not heated.
I hope this helps our thinking when choosing antibiotics
Peter Trademark*
