Resistant infections: beware of online shopping

Pubblicato il

Tuesday, 14 May 2024

Argomento

Eye infections

Reported cases of keratitis from Pseudomonas aeruginosa, resistant to all common antibiotics, eventually managed with an 'off-label' antibiotic, which fortunately proved effective.

Very difficult to treat and with enormous risks of chronic and permanent damage to visual function: these are multi-resistant eye infections, a reality that is unfortunately becoming increasingly widespread and worrying. On this subject, we would like to tell you about the case of resistant infections, caused by eye drops purchased online, which were managed thanks to the topical 'off-label' administration of an antibiotic authorised for other uses.

Severe forms of keratitis resistant to all common antibiotics emerged in 2023 in the United States and were described in a clinical study published in December 2023 by Ophthalmology Science.

The infection was caused by the use of contaminated packets of artificial tears, purchased online - we recommend you be very careful when purchasing drugs on the web - and was found in 81 patients, residing in 18 states.

The cause of this infection resistant to common antibiotics has been identified in a strain of Pseudomonas aeruginosawhich had so far not been detected in the United States. Scientists immediately raised the alarm of possible inter-human, person-to-person transmission through contact. According to official data, this infection by Pseudomonas aeruginosa caused loss of sight in 14 patients, surgical enucleation of the eyeball in 4 patients and, unfortunately, also 4 deaths.

Eric G. Romanowski, research director of the Charles T. Campbell Ophthalmic Microbiology Laboratory at the University of Pittsburgh (Pennsylvania) Medical Center, told the ARVO 2024 Congress, held in Salt Lake City, Utah (USA) from 4-8 May 2024, how his lab conducted studies to evaluate an antibiotic, the topical cefiderocol, as a potential treatment option for these cases of multi-resistant infection.

Researchers from Dr. Romanowski's group, together with colleagues from the Geisel School of Medicine at Dartmouth University in Hanover, New Hampshire, had discovered that the strain of Pseudomonas aeruginosa multi-resistant was sensitive to cefiderocol, an antibiotic approved by the Food and Drug Administration (FDA) in 2019 as a treatment for urinary tract infections, but never tested in vivo as an eye drop.

They then tested topical cefiderocol at the lowest inhibitory concentration (MIC) to assess its efficacy on 135 isolates taken from infected eyes and verified its toxicity and antibiotic efficacy in vivo on an experimental model of keratitis in rabbits, caused by the multi-resistant strain of Pseudomonas aeruginosa.

Topical Cefiderocol was well tolerated and had no toxic effects on the rabbit cornea and was also effective in samples of infected isolates.

In the study, the researchers emphasise how there is still a lack of consensus on which antimicrobial strategy is most effective for managing largely antibiotic-resistant forms of keratitis.

In the acute phase, when more cases of this keratitis were recorded by Pseudomonas aeruginosa, Clinicians had tried different treatment protocols with mixed results. In one case, the combination of intravenous cofiderocol and other topical and oral drugs appeared to be successful.

At that point, Dr. Romanowski and his team decided to try cefiderocol in eye drops, just "as doctors - "as a duty to the profession" - as this use is not officially authorised (off label).

Clearly, the results obtained are a prerequisite in terms of evidence-based medicine in order to be able to add cefiderocol in eye drops in the future to the antibiotics that any clinician may decide to use to combat resistant infections in emergency situations.