There is alarm in the United States for a bacterium resistant to various antibiotics that has caused serious infections that have caused loss of vision in eight people, three deaths and four operations for the surgical removal of the eyeball. To cause them, a strain of Pseudomonas aeruginosa which would be linked to the use of artificial tears of widely used brands. The notice has come Centers for disease control and prevention (Cdc) who are collaborating with the Food and drug administration (FDA) and health departments to investigate the outbreak. According to the CDC, the infection has been reported in at least 16 states. The bacteria, described as ‘largely resistant to drugs’, are associated with multiple types of infections, including those of the eyes.
Recalled two products
All 68 patients reported using different brands of artificial tears before noticing symptoms. Some patients have used multiple brands. The health authorities consequently recalled two products: the artificial tears produced by EzriCare and those produced by Delsam Pharma (not marketed in Italy). EzriCare Artificial Tears, an over-the-counter preservative-free product packaged in multi-dose vials, were the most commonly reported brand. The carbapenem-resistant strain of Pseudomonas aeruginosa (class of antibiotics) had never been reported in the United States prior to this outbreak. Health authorities advise patients who have used these products to seek immediate medical attention if they experience any signs or symptoms of an eye infection, which may include: discharge, pain or discomfort, redness of the eye or eyelid, body sensation stranger, increased sensitivity to light, blurred vision.
Pseudomonas aeruginosa
CDC laboratory testing identified the presence of carbapenem-resistant Pseudomonas aeruginosa in opened vials of EzriCare from multiple lots; these vials were collected from patients with and without eye infections in two states. The bacterium recovered from the opened products corresponds to the outbreak strain. Testing of unopened vials of EzriCare Artificial Tears is ongoing to evaluate if contamination may have occurred during manufacturing. Patients and healthcare professionals should immediately stop using EzriCare and Delsam Pharma artificial tears pending further information and guidance from the CDC and FDA.
Drug resistant
This strain of P. aeruginosa was insensitive to many antibiotics: cefepime, ceftazidime, piperacillin-tazobactam, aztreonam, carbapenems, ceftazidime-avibactam and ceftolozane-tazobactam, fluoroquinolones, polymyxins, amikacin, gentamicin and tobramycin. Three samples were found to be sensitive to cefiderocol, a new antibiotic for the treatment of superbug infections which recently obtained the designation of “full innovativeness” from the Italian Medicines Agency. It is a latest generation cephalosporin, indicated for the treatment of adult hospitalized patients with serious infections caused by bacteria resistant to the antibiotics used up to now, for example carbapenems: enterobacteria, Pseudomonas aeruginosa, Acinetobacter and Stenotrophomonas maltophilia. The antibiotic therefore acts against the main gram-negative microorganisms, for which the other therapeutic options are now blunt weapons.
A dangerous bacterium
Pseudomonas aeruginosa is a Gram-negative bacterium, one of the most dangerous for humans, widespread in water, soil and plants. It has a good ability to survive in various environmental conditions, including hospital environments. In healthy people, P. aeruginosa can occasionally colonize the skin, external ear, upper respiratory tract, or large intestine. The most important infections caused by P. aeruginosa are pulmonary infections, septicemia, otitis, urinary and ocular infections, endocarditis and burn infections. WHO warns in particular against P. aeruginosa resistant to carbapenem class antibiotics.