Antibiotics State of affairs.

In August 2019, a pigeon was brought to the University of Warsaw (Poland) with severe clinical symptoms: dry nodular, yellowish lesions on the eyelids with bulging black poxes adhering to the nostrils but also the beak. There were also other abscesses in the palate.
It is a typical picture of a viral smallpox infection with diphtheria of the skin and mucosa. Swabs from the oral cavity were collected and then dissected with the isolation of the following pathogens:

Staphylococcus aureus is resistant to all tested beta-lactam antibiotics, for example, penicillin molecule with a fragile central ring, as shown in the picture below. It is also resistant to Amikacin, Gentamycin, Tetracycline, Doxycycline, Florfenicol, Clindamycin, and Erythromycin. Intermediate susceptibility was only confirmed for Enrofloxacin. The detection of the mecA gene (the ability to resist) in the Staphylococcus aureus strain correlated with the antimicrobial resistance phenotype indicative of MRSA (Methicillin-resistant S. aureus).

In blue, the beta-lactam ring in a penicillin molecule is broken open by an enzyme from resistant ESBL germs (Source: Wikipedia).

Further analyses revealed that E. Coli only had partial sensitivity to Amikacin, which was placed on the WHO list of essential antibiotics. In addition, it was resistant to all standard antibiotics.

These include Amoxicillin with Clavulanic Acid, Cefpodoxime, Cefalothin, Gentamicin, Tetracycline, Doxycycline, Sulfamethoxazole with Trimethoprim, Florfenicol, Enrofloxacin and Ampicillin.

Amikacin (bron Wikiwand)

Both bacteria were resistant to at least three antimicrobial classes and could thus be classified as multi-resistant pathogens.

In mycological (fungal) research, Candida albicans was resistant to Clotrimazole, Natamycin, Flucytosine and Amphotericin. It was also moderately sensitive to Ketoconazole, Nystatin and Econazole.

The owner of this pigeon "apparently" administered 10% Florfenicol - obtained from an unknown source - orally, despite the result of the antibiogram. The outcome of the disease remained unknown.

The facts.

In this case, three different pathogenic microorganisms were isolated from an affected carrier pigeon, and all three were multidrug-resistant.

Although the increased resistance to antimicrobial agents in bacteria and fungi is now well known, errors in antimicrobial therapy are still common. For example, antibiotics are still administered 'blindly', without prior microbiological examination, and the choice of drug is often random.

Antimicrobial therapy must be based on an antibiogram (antimicrobial susceptibility testing) and a veterinary prescription. In many cases, antibiotics are not necessary because the cause of an illness is often not bacterial.

Voorbeeld van een antibiogram 

Another common problem is the incorrect dosage and treatment duration that is too long or too short. Often, the therapy is not continued as soon as the clinical symptoms disappear.

Before the competition, carrier pigeons often receive preventive antibiotics to treat any possible illness. This is done even if the pigeon does not show any clinical symptoms. There are even more irresponsible practices concerning antibiotics among show pigeon and homing pigeon breeders.

Antibiotic cocktails (preparations of antibiotics of different classes) are frequently purchased from unknown sources and then shared between breeders. These cocktails may contain not only antimicrobials registered for pigeons or other animals but also substances registered for humans. 

The resistance of E. Coli to Enrofloxacin (e.g. Baytril) and Doxycycline (for example, Soludox) and the resistance of Staphylococcus aureus to Doxycycline partial sensitivity to Enrofloxacin may be associated with extensive use of those antimicrobials. In Poland, these are approved for the treatment of pigeons.

Further analysis of the resistance issue.

Other research groups in various countries previously described similar observations on pigeon pathogens.
The resistance to the antibiotics listed below, which are not registered for use in pigeons in Poland, suggests the possible acquisition of resistance through other bacteria. So does an effect of selective pressure caused by unauthorised treatment with antibiotics from these three classes.

• Aminoglycosides (Gentamicin, Tobramycin and the semi-synthetic derivatives Netilmicin and Amikacin).
• Macrolide (Erythromycin)
• Phenols (Chloramphenicol group)

Only one report on the presence of MRSA (Methicillin-resistant Staphylococcus aureus) in pigeons has been reported in Poland.

In Iran, multi-resistant, biofilm-producing MRSA strains were also found in pigeons with conjunctivitis (eye infection). Moreover, it was demonstrated in Italy that pigeons could be colonised by MRSA (Methicillin-resistant S. aureus). Multiresistant E. Coli was also found in this study. 

It has previously been shown that pigeons are a reservoir of multi-resistant E. Coli, including ESBL-producing strains that can break the central "beta-lactam ring" of penicillin.

It was also discovered that feral pigeons carried ESBL-positive E. Coli strains.

Cumulative data, based on the analysis of available publications on antimicrobial resistance in E. Coli isolated from pigeons, showed that most of them were resistant to tetracyclines. This may be because tetracyclines are registered for birds in many European countries, including Poland.

Fluoroquinolones are another class of antimicrobials (Baytril family) registered for birds. In addition, according to cumulative data from several studies, 29% of strains were reported to be resistant.

The highest percentage of strains was resistant to Olaquindox, an antibiotic used in medicated feed, mainly used as a growth promoter in livestock. However, the data on this antibiotic came from only one Chinese study. The researchers compared the differences in resistance to different classes of antibiotics of E. Coli strains isolated from wild and domestic pigeons. In general, E. Coli strains obtained from domestic pigeons showed higher resistance to all antimicrobials tested except for Nitrofurantoin.

It is noteworthy that most of the studies on the occurrence of multi-resistant zoonotic germs (which can also be transmitted to humans [°]) concerned feral pigeons. These infectious germs were isolated from faeces from healthy birds. There are only limited records of such pathogens being found in clinical samples. However, these are mainly obtained from racing pigeons.

[°]We like to refer to a worthy presentation of Elkerliek concerning the resistance problem on a European level:

Conclusion.

It is clear that the three pathogens discussed above - which can also be transferred to humans - have the pigeon as their permanent host. The pigeons can live in equilibrium with them, even to the extent that they are found in healthy pigeons in the wild.

The pathogens are routinely found in (domestic) racing pigeons. It shows that the misuse of antibiotics upsets the subtle balance and thus significantly increases the risk to humans.

Microorganisms that have been living on the Earth for 200 million years are not going to allow themselves to be bullied by antibiotics. They are now striking back efficiently. We have no answer to them, so we stand there like burned-out saints. (Not to mention viruses.)

For this reason, decades ago, COMED developed its vision of tackling infections in pigeon racing without administering antibiotics, namely with resistance selection. If we have to select pigeons anyway, we do it better based on their resistance to these germs. We leave behind the pigeons that do not live up to the expectations with the Comed schedules.

Of course, we respect conventional medicine and the value and proper place of antibiotics from a medical perspective. Therefore, antibiotics should always be administered under the supervision of a veterinarian.

• He examines whether and when antibiotics are needed.
• He knows best which antibiotic should be administered, when, in what dosage and for how long, whether or not after a laboratory test (antibiogram).
  

Of course, this requires a trusting relationship with the veterinarian. Prescribed treatment must be strictly adhered to. 

"Health is a serious matter: either you choose a customised treatment from your veterinarian or choose resistance selection with the schedules of Comed's pharmacists."

There is no other path!