Abstract
Abstract: :
Purpose: To identify environmental reservoirs of Rapidly Growing Mycobacteria (RGM) species in South Florida and characterize the frequency, biofilm production and antibiotic susceptibility profiles for RGMs recovered from lasik versus nonlasik patients. Methods: Environmental samples (N =165)- municipal drinking waters (50), ice machines (24), eyewash stations (25), recreational waters (54), bottled waters (9) and sterile irrigation solutions (3) were collected and cultured to R/O RGMs. Qualitative (stain) and quantitative (spectrophotermeter) assessment of isolates (N =36, cornea (lasik)-10, cornea (nonlasik)-12, ocular other-14) adherence to glass, microtiter plates and cellulose filters were used to score biofilm production. E tests and Mueller Hinton agar supplemented with 10% OADC were used to evaluate invitro susceptibility to clarithromycin, amikacin, tobramycin, linezolid, ciprofloxacin, ofloxacin, levofloxacin, moxifoxacin and gatifloxacin. Results: Rapid growing Mycobacteria were recovered from 36.6% of the environmental samples. Highest recovery rates included: drinking water (50%), swimming pools (48%), ice machines (33%) and eyewash stations (16%). M. chelonae/abscessus grp (N=19) was more likely to be recovered from lasik patients (100%), than nonlasik cornea patients (67%) or sources other than cornea (47%). Biofilm formation was detected in 50% of all isolates and was significantly associated only with isolates from biomaterial-centered infections (prosthesis, buckles, sutures, and contact lens). Linezolid (97%) and clarithromycin (92%) were the most active invitro drugs. Susceptibility to the Quinolones and aminoglycosides were species dependent. Quinolones were most active against M. fortuitum (N=8, 100%). Gatifloxacin (4x) and moxifloxacin (3x) more active than ciprofloxacin for these isolates. Aminoglycosides (100%)were most active against M. chelonae (N=14).Conclusions: Drinking and swimming pool waters may serve as common reservoirs for RGM infections. Speciation and susceptibility profiles are mandatory for selection of adequate therapy. Clinical efficacy of linezolid against ocular RGM warrants investigation.
Keywords: bacterial disease • clinical laboratory testing • keratitis