Antibiotic therapeutics are used to treat confirmed bacterial cases and, in some cases, mere suspects as well. However, liberal use of them can result in antibiotic resistant strains of bacteria and, eventually, untreatable disease. The research community is on the watch for that eventuality and an update to the well-known Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) study shows that bacteria continue to win the war.

Methicillin resistance and multidrug resistance are prevalent among staphylococci, according to the investigators. They looked into more than 6,000 isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa and Haemophilus influenzae collected between 2009 and 2018.

Specifically, the research team note in the study, S. aureus and CoNS isolates were most methicillin resistant and more likely to be concurrently resistant to macrolides, fluoroquinolones and aminoglycosides compared with methicillin-susceptible isolates. Multidrug resistance was observed among methicillin-resistant S. aureus.

Differences in antibiotic resistance were found among isolates by patient age, with older patients more likely to have resistance than pediatric patients. However, the study shows, even for pediatric patients, the mean percentage of antibiotic resistance—including methicillin resistance among staphylococcal isolates—was notable.

The study did show that P. aeruginosa and H. influenzae isolates have low resistance overall.

Although resistance is high, the researchers note that the resistance profiles were mostly unchanged during the 10-year study period.

Asbell P, Sanfilippo C, Sahm D, et al. Trends in antibiotic resistance among ocular microorganisms in the United States from 2009 to 2018. JAMA Ophthalmol. April 9, 2020. [Epub ahead of print].