ARMOR, a New Prospective, Multicenter Surveillance Study to Determine the in vitro Activity Profile of Besifloxacin and Comparators Against Ocular Pathogens From the US

Abstract

 

Purpose:

 

It is important to track resistance trends among target pathogens to current agents and monitor for the emergence of resistance to recently approved agents such as besifloxacin (BES). This study reports susceptibility data for BES and comparators against ocular isolates of Gram-positive and -negative ocular pathogens collected across the US.

 

Methods:

 

In 2009, ocular isolates (144 S. aureus, 112 coagulase-negative staphylococci (CNS), 92 P. aeruginosa, 47 H. influenzae, and 41 S. pneumoniae) were collected from 21 hospitals across the US and were tested against BES, ciprofloxacin (CIP), moxifloxacin (MXF), azithromycin (AZM), and tobramycin (TOB).

 

Results:

 

Table 1 shows MIC₅₀/MIC₉₀ (µg/mL) values for five of the test agents. Against methicillin resistant S. aureus (MRSA) and CIP non-susceptible (NS) isolates BES had an MIC₅₀/MIC₉₀ of 1/4, relative to 4/16 for MXF and 64/256 for CIP. Against MR-CNS and CIP-NS isolates, BES had an MIC₅₀/MIC₉₀ of 0.25/4 and 0.5/4 respectively, several fold more potent than MXF (MR-CNS: 1/32; CIP-NS: 2/32) and CIP (MR-CNS: 16/64; CIP-NS: 64/64).

 

Conclusions:

 

BES was the most potent agent evaluated against Gram-positive cocci and was several-fold more potent against methicillin and fluoroquinolone resistant isolates. BES was comparable to other fluoroquinolones against H. influenzae, and was similar to MXF but less potent than CIP against P. aeruginosa. These results highlight the potential of BES for the treatment of ocular infections. Continued surveillance to monitor the emergence of resistance to current topical ophthalmic agents, including BES, is warranted.  

 

Keywords: antibiotics/antifungals/antiparasitics • bacterial disease • Staphylococcus