Antibiotic of the week: Spiramycin

Antibiotic Pollution Index: 37 (12 October 2017)
What is the Antibiotic Pollution Index?

What it does
Spiramycin belongs to a family that inhibits protein synthesis. Protein synthesis is an essential process. Proteins digest, transport, arrange and manipulate all sorts of cell components. In low dosages, spiramycin stops bacterial cell growth; in high dosages, it may kill the bacteria.
In the body, spiramycin is metabolized to neo-spiramycin, which is also an antibiotic agent. Ignoring this metabolic step may lead to an underestimation of antibiotic residue after spiramycin consumption.

Who gets it
Spiramycin is available in the EU and many other regions, but not in the USA. It is effective against a number of bacterial infections (such as Streptococcal, Legionella, Chlamydia, Mycoplasma) and is also used to treat toxoplasmosis, a parasitic infection. Veterinary use often targets respiratory infections. Spiramycin tends to bind to and accumulate in specific tissues, such as tonsils, bronchi, and (after injection) muscle around the injection site. This has advantages to target infections in those tissues, but its mixed accumulation in different organs challenges its use in the veterinary sector. Withdrawal periods -depending on the animal- up to 52 days have been recommended for this drug. Consumers may be exposed to spiramycin if withdrawal periods are not obeyed. For instance, micrograms per chicken egg can still be detected up to 10 days after treatment.

Where may it be produced?
France, China.

And, SquaredAnt, does it pollute?
For now, SquaredAnt only found one report of spiramycin in an environmental sample.

Warning lights
In France, resistance levels to spiramycin are high in some bacteria in pigs: up to 77% of Streptococcus suis is resistant against this drug. This particular pathogen has many resistance phenotypes. In Brazil, for instance, 99.61% of Strep. suis in healthy pigs is multi-drug resistant against at least 3 out of 16 antibiotics (spiramycin was not included in this analysis). This indicates that gradually, options to control Strep. suis infections are getting less. Strep. suis can infect humans, too. Alltogether, advancing resistance in this pathogen potentially has public health consequences.

Any common sense in this antibiotic?
The Antibiotic Pollution Index for this antibiotic is relatively low. This is likely the result of a limited usage of this drug on a global scale and its absence on the US market. The Strep. suis example shows us, however, that one day this drug may replace antibiotics that have been phased out due to antibiotic resistance. It will then be important to strictly control the use, as spiramycin resistance is related to its usage. Avoiding additional resistance phenotypes should be prioritized.


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