JAC Advance Access originally published online on July 24, 2006
Journal of Antimicrobial Chemotherapy 2006 58(3):575-579; doi:10.1093/jac/dkl290
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In vitro inhibitory effect of antituberculosis drugs on clinical and environmental strains of Coccidioides posadasii
1 Medical Mycology Specialized Center, Federal University of Ceará Fortaleza, Ceará, Brazil 2 Post-graduation Program in Medical Sciences, Federal University of Ceará Fortaleza, Ceará, Brazil 3 Department of Biological Science, State University of Ceará Fortaleza, Ceará, Brazil 4 Post-graduation Program in Veterinary Science, State University of Ceará Fortaleza, Ceará, Brazil 5 Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo São Paulo, Brazil
Received 26 February 2006; returned 12 April 2006; revised 22 May 2006; accepted 23 June 2006
*Corresponding author. Tel: +55-85-214-2853; Fax: +55-85-295-1736; E-mail: ross{at}uece.br
Objectives: The aim of the present study was to evaluate the in vitro effect of the first-line antimicrobial drugs for pulmonary tuberculosis against the fungal pathogen Coccidioides posadasii.
Methods: The in vitro activities of rifampicin, isoniazid, pyrazinamide and ethambutol against clinical and environmental strains of C. posadasii were determined in accordance with the CSLI M38-A macrodilution method. The antimicrobials were tested alone or in combinations of two or more drugs.
Results: With the exception of pyrazinamide, all of the tested drugs interfered with the in vitro growth of C. posadasii. The 2 day MIC ranges of the tested drugs were as follows: rifampicin 10604250 mg/L; isoniazid
250 mg/L; ethambutol
620 mg/L. Pronounced in vitro synergism was demonstrated for combined antituberculosis drugs. The combination of rifampicin plus pyrazinamide was the only one that did not inhibit fungal growth.
Conclusions: The present study showed that the first-line antituberculosis drugs, alone or in combinations, interfered with the vegetative growth of C. posadasii strains in vitro. Further studies in a murine model will need to be conducted in order to evaluate the in vivo effect of antituberculosis drugs on Coccidioides spp.
Keywords: susceptibility testing , coccidioidomycosis , pulmonary tuberculosis , Brazil