Trichophyton rubrum and Trichophyton mentagrophytes complex, or Trichophyton spp. are the main etiologic agents of dermatophytosis, whose treatment is limited by the high cost of antifungal treatments, their various side effects, and the emergence of resistance amongst these species. This study evaluated the in vitro antidermatophytic activity of 23 crude extracts from nine plant species of semiarid vegetation (caatinga) found in Brazil. The extracts were tested at concentrations ranging from 1.95 to 1,000.0 mg/mL by broth microdilution assay against the reference strains T. rubrum ATCC 28189 and T. mentagrophytesATCC 11481, and 33 clinical isolates of dermatophytes. All plants showed a fungicidal effect against both fungal species, with MIC/MFC values of the active extracts ranging from 15.6 to 250.0 µg/mL. Selected extracts of Eugenia uniflora (AcE), Libidibia ferrea (AE), and Persea americana (AcE) also exhibited a fungicidal effect against all clinical isolates of T. rubrum and T. mentagrophytes complex. This is the first report of the antifungal activity of Schinus terebinthifolius, Piptadenia colubrina, Parapiptadenia rigida, Mimosa ophthalmocentra, and Persea americana against both dermatophyte species.

By Time Kill Curve Assay, we could observe in M. tuberculosis HRv and susceptible isolates, that LZD alone, at sub inhibitory concentration, has poor effect on the bacillus death. In some cases, the bacillus growth stayed constant while in others showed regrowth at the eighth day of drug exposure. RIF alone exhibits potent concentration-dependent bactericidal activity, and was strongly dependent by the drug exposure time. The RIF/LZD combination accomplished a bacteriostatic effect in the reference strain and susceptible isolates. For the RIF resistant isolates, the RIF/LZD combination did not enhance the effect in killing bacillus. In this sense, additional, in vitro and in vivo studies are needed to evaluate the effect of RIF/LZD combination in order to better understand the adjunctive action of LZD in the treatment of TB and prevent the emergence of mutants with resistance to the available anti-TB drugs.

The aim of the present study was to evaluate the effect of the combination of rifampicin (RIF) and verapamil (VP) against the Mycobacterium tuberculosis H37Rv reference strain and six multidrug-resistant (MDR) M. tuberculosis clinical isolates by determining Time-Kill Curves and the ability to efflux drug by fluorometry. The RIF+VP combination showed synergism in one MDR clinical isolate. For the other five MDR clinical isolates, the drug combination showed no interaction. The MDR clinical isolate had lower ethidium bromide (EtBr) accumulation when exposed to the RIF+VP combination, compared with RIF and VP exposure alone. The other MDR clinical isolates showed no significant difference in EtBr accumulation. These results suggest greater efflux action in one of the MDR clinical isolates compared with the M. tuberculosis H37Rv reference strain. The other five MDR isolates may have additional mechanisms of drug resistance to RIF. The use of the RIF+VP combination made one MDR bacillus more susceptible to RIF probably by inhibiting efflux pumps, and this combination therapy, in some cases, may contribute to a reduction of resistance to RIF in M. tuberculosis.

Primeira submissão em 30/11/11 Última submissão em 24/05/12 Aceito para publicação em 10/09/12 Publicado em 20/10/12 Suscetibilidade a antifúngicos in vitro de Candida spp. em pacientes do Hospital Universitário Regional de Maringá-PR Antifungal susceptibility of Candida spp. in vitro among patients from

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