Analysis finds besifloxacin effective against polymicrobial infections

VANCOUVER, British Columbia – An evaluation of outcomes data from three clinical trials showed that 17% of patients had polybacterial ophthalmic infections at baseline, and that treatment with besifloxacin resulted in eradication rates of 90% or higher.

The analysis reported here at the Association for Research in Vision and Ophthalmology meeting involved 1,041 subjects (mean age 33 years) with culture-confirmed conjunctivitis. According to the abstract, 83% were infected with two species, 15% were infected with three, and 2% were infected with four. The most common species was Haemophilus influenzae followed by Staphylococcus aureus.

“The patients who had polymicrobial infections did very well on besifloxacin, and it was highly statistically significant when compared to vehicle alone,” lead author Joseph M. Blondeau, MSc, PhD, RSM(CCM), SM(AAM), SM(ASCP), FCCP, head of microbiology at Royal University Hospital and the University of Saskatchewan in Saskatoon, told Healio.com/OSN.

“This is confirmation of the importance of polymicrobial infections,” he said, “and it also shows that the patients who received besifloxacin did very well regardless of having a mixed polymicrobial infection.”

He said these findings have important clinical implications.

“If organisms have different levels of susceptibility to an antibiotic and you’re targeting one organism, it may not be effective against the other ones, and it would lead to persistence of symptoms or maybe even treatment failure,” he said. “Now we’re starting to investigate how well does besifloxacin kill organisms when they’re in mixtures as opposed to individually.”

While this study showed that 17% of these patients had polybacterial infections, data from his hospital in the past year indicated a figure of 27%.

This supports a case for culturing, he said.

“Ophthalmology is one area where the lab is poorly utilized,” Blondeau said. “I’ve always argued that using the lab upfront helps confirm that an organism is present or not, whether it’s a single or multiple organisms and what the antibiotic susceptibility or resistance profiles are. That gives assurance that you’re making the right drug choice.”

This analysis found evidence of both gram-negative and gram-positive organisms.

“In this particular trial, the patients who had mixtures did well on besifloxacin regardless of what the mixture was,” Blondeau said. – by Nancy Hemphill, ELS, FAAO

Reference:

Blondeau JM, et al. Incidence of polybacterial infections in three bacterial conjunctivitis studies and outcomes with besifloxacin ophthalmic suspension 0.6%. Presented at: Association for Research in Vision and Ophthalmology; April 28-May 2, 2019; Vancouver, British Columbia.

Disclosure: Blondeau reports no relevant financial disclosures. Please see the study abstract for all other authors’ financial disclosures.