Wednesday, July 24, 2024

Gram Negative Antibiotics For Fish

When Not To Use Medication:

Mechanisms of Resistance in Gram negative Bacteria to Beta Lactam Antibiotics

Many readers of my articles both here at American Aquarium Information and Aquarium/Pond Answers might think I m very pro medication use based on how much information is about medications and their use.HOWEVER in actual application over the years, I rarely use medications, in part based on practicing what I preach in article such as “Aquarium Disease Prevention”.Even when a fish might be a candidate for medication use, I still will attempt basic baths as a starting point or simply not treat in the case of an older or genetically weak fish where a medication might actually do more harm than good.

Here are some very simple points as to when NOT to medicate your fish :

Some Common Antibiotics Used In Aquariums

  • Erythromycin which treats gram positive bacteria and is best used in an alkaline environment .
  • Aminoglycosides marketed as neomycin, kanamycin and streptomycin are active against gram negative bacteria and work well in alkaline water conditions.
  • Sulfonamide known as sulfa or triple sulfa have antibacterial characteristics inhibiting the growth of bacteria. An alkaline environment is preferred and sulfonamide as well as aminoglycosides can be used in marine environments.
  • Nitrofurans are also antibacterial but will loose their potency with increasing pH levels. They are therefore preferred freshwater treatments as is the tetracycline group.
  • Tetracycline is bacteriostatic, inhibiting protein synthesis. This drug will get less effective in hard waters as it readily binds with calcium and magnesium.
  • Quinolones, antibacterial to treat gram negative bacteria, prevents DNA synthesis and can be used in a broad pH spectrum.

Bacterial diseases in fish can face antibiotic resistance, which means that the bacteria strain has mutated leaving it unaffected by the antibiotic. Another antibiotic will have to be used should this occur.

Bacterial diseases are not contagious and infected fish should be treated separately in a well aerated hospital tank. Antibiotics are potent by themselves and never meant to be used in combination, as some of them can eliminate each other or create toxic effects for fish.

Keep in mind that the beneficial bacteria are gram negative as well.

Understanding The Active Ingredients In Antibacterial Aquarium Medications

Posted by: Eileen Daub in Fish HealthDecember 16, 201328128 Views

Understanding what a medication contains can often be as or more important than understanding what it treats. Ive compiled just a few of the most common active ingredients found in many of the most popular aquarium medications. This list is not all-inclusive but may hopefully help to unravel the whys and hows of some medications.

Remember, some of these active ingredients have more than one use and the medications they are in may be marketed for different uses. Antibacterial medications may be included in anti-parasitic medications and some anti-parasitic ingredients may also be useful in fungal infections but the uses Ive listed are the most common or most effective in the aquarium trade. Always remember to properly diagnose conditions and diseases before medicating and follow the manufacturers instructions for any medications.

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Making False Assumptions When Medicating:

This is similar to the section above, however here I’m referring to aquarium and pond keepers use of medications vs. the previous section dealing with anecdotal advice.

A good example is the use of Erythromycin or Melafix for treating Columnaris which is gram negative and then assuming your use of Erythromycin cured this ailment when laboratory tests prove this impossible .What likely happened is some other part of your tank maintenance procedure took care of this opportunistic infection OR quite simply your fish did not even have Columnaris, rather Streptococcus or FNT Disease or other gram positive diseases.

More information on: Streptococcus& FNT Disease

Changing water or otherwise improving water conditions can often allow a fish overcome an opportunistic infection . This easily allows the aquarium keeper to assume that a treatment cured his/her fish.

My point is that this hobby is often driven by anecdotal assumptions that I would like readers to avoid by thinking more scientifically.A controlled study of medication use would include control groups, exact maintenance/water change procedures and more to keep different medication tests accurate.Obviously the aquarium or pond keeper when confronted with sick fish does not have time or multiple aquariums/ponds to perform these tests.

Molecular Typing Of The Virulence And Antibiotic

Fish Zole Forte Fish Antibiotic

DNA of purified strains was extracted using a silica-based membrane QIAamp DNA Mini kit according to the manufacturers instructions. Genomic DNA templates were quantified using Nanodrop , adjusted to 100 ng L1, and stored at 20 °C until used for PCR. Ninety representative P.aeruginosa strains were tested for the detection of virulence genes, four sets of primers targeting genes were selected based on the previous publications of Xu et al., Winstanley et al., Finnan et al., and Matar et al., respectively. Further, to verify the resistance of retrieved strains to the commercially available antibiotics, three sets of primers targeting blaTEM, tetA, and blaCTX-M genes were also selected according to Colom et al., Randall et al., and Fazeli et al., respectively. All primers supplied by , and their oligonucleotides sequences and PCR conditions are given in Table . PCR reactions were amplified in T100 Gradient Thermocycler using EmeraldAmp GT PCR Master Mix . A reaction with no template DNA was used as a negative control, while a virulent reference strain of P.aeruginosa , kindly provided by Animal Health Research Institute in Dokki, Cairo, Egypt, was used as positive control. The products were screened by horizontal 1.5% agarose gel electrophoresis and then photographed.

Table 1 List of oligonucleotide sequences and their PCR conditions used in the current study.

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Consequences Of Improper Dosage And Treatment Time

If the dose is too high or treatment times are too long, there is a danger of toxicity to the fish, frequently causing liver, kidney, or other organ damage that may or may not be reversible.

On the other hand, if the dose of antibiotic is too low or treatment time is too short, the bacteria will not be killed or weakened enough for the immune system of the fish to remove them, and this greatly increases the risk of the bacteria developing resistance to the antibiotic. When bacteria become resistant to a specific antibiotic, even high concentrations of that drug will not be effective.

Antibiotic resistance can also occur when antibiotics are used improperly, such as the ‘shot-gunning’ method. ‘Shot-gunning’ involves administering one antibiotic after another to a population of fish, frequently at improper dosages, for shortened treatment times, and without the aid of proper diagnosis . If shot-gunning is used frequently at a facility, resistance is almost certain to occur. In some cases, the problem may not be due to bacteria, but rather poor water quality or other management issues that have not been properly investigated.

What You Need To Do

1. Get the Capsules:

Buy a bottle of 100 x 250mg capsules of Fish Mox available at pet stores. The capsules come in different colors generally tan/yellow and light pink/dark pink.

2. Medicate according to the size:

  • If you are treating an animal that weighs 5 lbs or more, take three capsules.
  • Pull apart the capsules and dump the powder of three capsules into a little bottle that can hold 15 ml/cc of fluid and has a lid. Add 15 ml/cc of clean water.
  • Oral dosage is 5-10mg/lb/day for seven days.
  • If you are dosing a small kitten weighing 1 to 2lb, only use one capsule and mix with only 5 ml/cc of water.

3. Storage:

  • Discard any unused mixed liquid apoxy after seven days. It will change color and is no longer good. You can store the capsules for a long time.

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How Do Bacteria Cause Disease

Although they are incredible small most pathogenic bacteria have tremendous reproductive potential. They simple divide in two and once each half has re-grown sufficiently they divide again. Under ideal conditions the reproductive cycle can be as little as 20 30 minutes, which means that just one bacterium can multiple to several million within 24-hours or so!

As I have said, bacteria are like little chemical factories. Some bacteria produce toxins that are excreted into the blood and tissues of the host. Other bacteria, particularly the Gram-negatives do not secrete a soluble toxin but make an endotoxin that is liberated when the cell dies and disintegrates. These endotoxins are usually lipopolysaccharide structural components of the bacterial cell-wall . In addition to toxins the virulence of many bacteria is partly due to the production of extracellular enzymes, which attack healthy fish cells.

So although tiny, the net effect of millions of bacteria can quickly overwhelm the defences of the fish host which is why early treatment is so vital if the fish is to survive.

Fish Mox As A General Term:

PetSolutions: Maracyn 2 Anti-Bacterial Fish Medication

Fish Mox and Fish Mox Forte are broad-spectrum antibiotics. They are efficient against a wide-ranging gram-negative and gram-positive bacterium in both types of waters as aquarium fishes and saltwater.

It helps in controlling gill disease, pop-eye, eye infections, and skin ulcerations.

It is one of the kinds of penicillin that is involved in targeting the bacteria causing disease and terminates their growth by preventing them from creating cell walls.

Thus, the drug halts the bacteria from reproducing and finally helps in getting relieved of the infection.

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Aquatic Treatments Which Ones To Use And Not To Use Aap Information Library

Sections On This Page Including:

A Healthy Aquarium Disease PreventionThe above article is based on many years of hands on experienced and controlled experiments. Following the steps outlined will provide the reader the highest chance of success with their aquarium keeping endeavors!

This article , has information about different aquarium and pond treatments. A gram negative or gram positive application is given where they apply. It is also noteworthy that not all human medications or veterinary are practical in aquarium or pond applications. A good example is Penicillin and Ampicillin .

Most bacteria which infect fish are gram-negative, including Aeromonas salmonicida, Flavobacterium columnare Vibrio, and Pseudomonas species.The major group of gram-positive bacteria which cause disease in fish are Streptococcus.

More about Gram Positive Streptococcus:

When you have fish that are sick , you want to try and isolate the fish in a hospital aquarium whenever possible. Of course, this should not be done if the infection is systemic.This is often seen with Ich or Gram positive infections such as Streptococcus.

Sponge Filters work great in hospital aquariums. Remember to remove any carbon, as carbon will remove many medications. Also note that silicone in the aquarium will absorb Malachite Green, Methylene Blue, and Copper Sulfate . Most corals crushed or similar, and ceramic decorations will also absorb medications.

Capsule 250mg In Water:

  • Take one 500mg Fish Mox, crush it to powder, then add in a medicine cup, add 10ml of water, shake well before each use, and keep in the fridge.
  • One way is that take one 250mg capsule and put it into a water gallon, shake it well and then make use of this as your felines only water supply for 7-10 days.

Recommended Reading: How To Get Rid Of A Bacterial Infection Without Antibiotics

Using The Right Antibiotic

Many bacteria are naturally resistant to specific drugs, so using the proper type of antibiotic is of the utmost importance. For example, gram-positive bacteria are often unaffected by tetracycline and streptomycin, while gram-negative bacteria may be unaffected by ampicillin, penicillin, erythromycin, and sulfa drugs. Some bacteria may also be unaffected by the usual dose but are susceptible to a higher dose.

Here is another good example. Mardel Laboratories makes Maracyn and . Maracyn is erythromycin based and is a gram-positive bacteria treatment. Maracyn 2 is mincycline hydrochlor based and is a gram-negative bacteria treatment, as well as sufficiently absorbed through the skin to treat internal infections. Since most bacteria that cause disease in marine fish are gram-negative, and can quickly become systemic, Maracyn 2 would be the most effective choice. Mardel also makes and distributes , which is a broad-spectrum antibiotic for controlling the bacteria that cause mouth fungus, fin and tail rot, Popeye, dropsy, and ulcers.

The overuse of antibiotics for treating fish is the same as with people. The repeated or continued use of antibiotics creates selection pressure favoring the growth of antibiotic-resistant mutants. Our advice is not to use antibiotics as a cure-all treatment whenever you feel the fish “might” need it, but only when it is necessary.

Gram Negative/ Gram Positive Bacteria

Fish Mox Forte

Here are a few terms:

*Gram-negative bacteria are pathogenic, as they can cause disease in a host organism and have a thin cell wall. Gram negative bacterial infections are much more common in fish, especially marine. These bacteria that will NOT retain a crystal violet dye during the Gram stain process.

Please click picture to enlarge

Here are some Gram Negative Bacteria:



– Cyanobacteria

Gram-positive bacteria do not always cause a disease in the host organism and have a very thick cell wall.Gram positive infections are less common in fish . These are the bacteria that retain a crystal violet dye during the Gram stain process.

Here are some Gram Positive Bacteria:

-Mycobacterium -Streptococcus -Pseudonocardia -Staphylococcus

Of the above bacteria noted, Flavobacterium , Vibrio, Aeromonas, & Pseudomonas cause the vast majority of diseases in aquariums/ponds AND these are gram negative. It should also be noted that Aeromonas and Vibrio are generally anaerobic, so keeping a well circulated/oxygenated aquarium or pond is important for their prevention and treatment.Mycobacterium is an occasional problem that is gram positive.

I have cited much of the information for this section from this source:

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Uses Of Tetracycline For Fishes

So, what does tetracycline treat in fishes? In ornamental fish, Tetracycline is used to treat a range of external and internal bacterial infections, consisting of these conditions:

  • Hemorrhagic Septicemia a bacterial infection of the bloodstream. Characterized by bloody streaks on the body and fins.
  • Cottonmouth disease a bacterial infection that impacts the mouth with fungi like growth and erosion of the mouthparts.
  • Fin Rot Fins and tail become ragged and torn, in many cases nearly entirely wearing down.
  • Gill Diseas e Fish breathe greatly, and gills appear intense red.
  • Open Body Sores Bacterial infection causing open red sores on the body.
  • Body Slime Slimy patches appear on the body, fish flashes against objects and breath quickly.
  • Pop-eye Eyes are hazy and may extend from the head.
  • Cyanobacteria likewise used to deal with cyanobacteria .

Usually, tetracycline is more efficient versus aerobic bacteria, mainly gram-positive organisms. In infections triggered by gram-negative germs, minocycline is more reliable than tetracycline. Tetracycline ends up being more potent as it ages, so expiration dates must be thoroughly stuck to.

High general hardness will minimize the effects of this drug. Tetracycline is ineffective at all when the water pH is higher than 7.5. Get rid of any carbon filter media when using this drug, as it will eliminate the Tetracycline from the water. Tetracyclines can be safely utilized together with Methylene Blue.

Change Medications When Ineffective:

Since fish treatment is far from an exact science. It’s important to try another antibiotic if after three treatments no results are seen .Also if some results are seen, but the fish goes backwards as to remission of symptoms, I would recommend changing antibiotics/antimicrobials as there may be bacterial resistance. Weaker treatments such as Melafix or Pimafix may result this way, as while these can be good products for mild infections, these are generally poor for more serious infections.

Sometimes where there was effectiveness, but not a full cure that a second treatment regimen often at a stronger dose may be called for .I do not recommend a 3rd treatment regimen, even if a different medication without a 7-10 day pause.

As I noted earlier, the majority of aquatic diseases are gram negative which make treatments with antibiotics such as Kanamycin or other gram negative antibiotics a good choice. This though is no guarantee that the disease pathogen will respond.Sometimes combinations of Kanamycin and Nitrofurazone give a wide spectrum treatment, and for really difficult treatments, these can be combined with the Parasite/Fungal treatment “ParaGuard”.Other times you may have to try very different antibiotics such as Erythromycin or Metronidazole (Erythromycin is a good choice for usually aerobic gram positive eye infections.Further information about eye infections:

Product Resources:*AAP Yellow Powder PREMIUM Nitrofuarazone

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What Antibiotics Cover Gram Negative Rods

4.6/5antibioticsmore on it

Piperacillin/tazobactam This antibiotic has activity against many Gram-positive, Gramnegative, and anaerobic pathogens. It covers Streptococci, Staphylococci , Hemophilus, Moraxella, Enterobacteriaceae, and Pseudomonas aeruginosa.

how do antibiotics affect gram negative bacteria? Gram negative cell walls contain high lipid content and the transport of antibiotics depends mainly on the outer membrane proteins. Multiple drug resistant mechanisms like efflux pump, enzyme alteration , alteration of target sites etc confers resistance to most of the antibiotics.

Just so, what are Gram negative rods examples?

The gramnegative bacteria include the model organism Escherichia coli, as well as many pathogenic bacteria, such as Pseudomonas aeruginosa, Chlamydia trachomatis, and Yersinia pestis.

What does it mean if you have gram negative rods?

Gramnegative bacteria cause infections including pneumonia, bloodstream infections, wound or surgical site infections, and meningitis in healthcare settings. Gramnegative infections include those caused by Klebsiella, Acinetobacter, Pseudomonas aeruginosa, and E. coli., as well as many other less common bacteria.

Safe Dosage Of Fish Mox:

Evaluating CAZ-AVI Against Antibiotic-Resistant Gram-Negative Organisms

The safer dosage depends upon the most important feature that is the SIZE of your cat and then dilution of the Fish Mox according to it. This is due to the reason that heavy dosages may have harmful effects on its system.

Pet liquid amoxy is 250 mg per 5 ml/cc. The recommended dose of amoxicillin oral suspension for your cats is 5-10mg/pound every 12-24 hours. Some give 10mg/lb on day one, then 5mg/lb day 2 7.

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