Abstract
Purpose: :
Ocular TRUST (Tracking Resistance in the US Today) is the only nationwide antimicrobial susceptibility surveillance program in isolates from ocular infections. Data from the second annual report from this ongoing program (Ocular TRUST 2) are presented.
Methods: :
Geographically distributed eye centers and community hospitals submitted samples from eye infections treated between October 2006 and June 2007. Isolates were tested by broth microdilution according to CLSI methodology at a centralized independent laboratory. The antimicrobial panel included azithromycin (AZTH), oxacillin, penicillin, polymyxin B, tobramycin, trimethoprim, and four fluoroquinolones (FQs): levofloxacin (LEV), ciprofloxacin (CIP), gatifloxacin (GAT), and moxifloxacin (MOX). MICs were interpreted as susceptible, intermediate, or resistant according to 2007 CLSI criteria. Oxacillin resistance was used as a marker for methicillin resistance and susceptibility in Staphylococcus aureus (MRSA, MSSA) and S. epidermidis (MRSE, MSSE).
Results: :
Ocular isolates: S. aureus (N=151;MRSA, n=83; MSSA, n=68); S. epidermidis (N=51; MRSE,n=31; MSSE, n=20); Streptococcus pneumoniae(N=188). Staphylococci susceptibilities toLEV, GAT, and MOX were identical,regardless of species or methicillin status(MRSA, 18%; MSSA, 93%; MRSE, 32%; MSSE,90%). Macrolide (AZTH) susceptibility:MRSA, 8%; MSSA, 62%; MRSE, 13%; MSSE, 40%.MRSA most susceptible to trimethoprim (95%). All S. pneumoniae isolates were susceptible toLEV, GAT, and MOX; 69% were susceptible toAZTH.
Conclusions: :
Nationwide susceptibility patterns of staphylococci and S. pneumoniae are identical for LEV, GAT, and MOX. Macrolide susceptibility (as represented by AZTH) was lower than FQs for ocular pathogens tested.
Keywords: bacterial disease • ocular irritancy/toxicity testing • antibiotics/antifungals/antiparasitics