Quinolones Susceptibility for Atypical Mycobacteria from Brazilian Lasik Outbreaks

Abstract

Abstract: : Purpose: To determine quinolones susceptibility for rapidly growing Mycobacteria (RGM) isolated from five outbreaks of infectious keratitis in Brazil. Methods: Mycobacterium chelonae and M. abscesssus from four outbreaks of infectious keratitis following LASIK for myopia correction were recognized in Brazil. A total of 13 M. chelonae and two M. abscessus identified by PCR– restriction enzyme analysis described by Telenti et al. (1993), had their MIC for ciprofloxacin, ofloxacin, gatifloxacin, and moxifloxacin determined with the E test methodology. The first two outbreaks occurred in Rio in 1998 (R–1; M. chelonae n=2), and 1999 (R–2; M.abscessus, n=1 ). The other three outbreaks occurred in São Paulo: SP–1 in 1999 (M. abscessus, n=1) , SP–2 in 2000– 2001 (M. chelonae, n= 8) and SP–3 in 2003 (M. chelonae, n=3) Results: For one strain of M. chelonae from the SP–2 outbreak the MIC 90 for Ciprofloxacin was 0,38ug/ml, ofloxacin – 0,125ug/ml, gatifloxacin – 0,032 ug/ml, and moxifloxacin – 0,032 ug/ml. Determination of MIC 90 for fourteen M. chelonae were greater than 32 ug/ml. The two M. abscessus strains have MIC greater than 32 ug/ml for all quinolones tested. Conclusions: RGM isolated in Brazil from infectious keratitis have high MIC for second or fourth generation quinolones. Further studies will be necessary to evaluate in vivo efficacy since the in vitro tests do not support the treatment of RGM keratitis with quinolones in our geographical area.

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