In vitro activities of 15 antifungal drugs against a large collection of clinical isolates of Microsporum canis

Abstract

Summary Background Microsporum canis is a zoophilic species, found to be the most frequently isolated species in animals. M. canis causes sporadic outbreaks of infections in humans, such as the one that occurred in Canada, where more than 1000 human cases were detected over an 8‐year period. Despite the medical importance of M. canis infections, there are limited in vitro data on the antifungal susceptibility to antifungal drugs, including new generation triazoles and imidazoles. Objective The aim of the current study was to comprehensively evaluate the in vitro activity of new azoles and comparator drugs against a large panel of M. canis isolates using a microdilution assay. Methods The in vitro susceptibility to novel triazoles and imidazoles was compared to that of other antifungal drugs using a large collection of M. canis clinical isolates (n = 208) obtained from patients and animals with dermatophytosis in Iran, France and Turkey. Results All isolates exhibited high susceptibility to the majority of the tested antifungal agents. However, luliconazole, lanoconazole and efinaconazole, as well as econazole, demonstrated superior activity against all strains in comparis on with the other drugs. Conclusion FDA‐approved antifungal drugs, that is luliconazole, efinaconazole and lanoconazole, showed the highest antifungal activity and should be promising candidates for the treatment of dermatophytosis caused by M canis. However, their therapeutic effectiveness remains to be determined in clinical settings.

Comparison of in vitro activities of 11 antifungal agents against Trichophyton verrucosum isolates associated with a variety hosts and geographical origin

“…Terbinafine has also been one of the drugs of choice for the treatment of human and animal dermatophytosis, particularly tinea capitis, in recent years . Although full resistance to terbinafine has recently been reported in T. interdigitale and T. rubrum isolates, no terbinafine‐resistant T. verrucosum isolates have been documented .…”

“…An alarming trend of recalcitrant dermatophyte infections in Europe has been noted recently, which may be related to inadequate or discontinued treatment, difficulties in eliminating predisposing factors in hosts or infection sources, and frequent reinfections . In scientific literature, there are not many data available regarding drug resistance in dermatophytes, but it is suggested that the resistance is on the rise .…”

“…36 Our results indicate that the in vitro antifungal activity of fluconazole against animal isolates (geometric mean of MICs = 124.18 μg/mL and MIC 90 = 128 μg/mL) was lower than the activity of the other azoles, echinocandins and allylamines (Table 1), which is consistent with previous findings. 17,37 Moreover, for the majority of the examined antifungal agents, except clotrimazole, itraconazole, ketoconazole, terbinafine and voriconazole, the geometric means of the MIC values were similar for the human and animal T. verrucosum isolates, although the human strains showed slightly higher susceptibility to ciclopirox and naftifine ( Table 3). It can be suggested that the activity of this drug is higher in younger individuals or there are some regional determinants of resistance.…”

“…Europe has been noted recently, which may be related to inadequate or discontinued treatment, difficulties in eliminating predisposing factors in hosts or infection sources, and frequent reinfections. 3,4,13,17,29 In scientific literature, there are not many data available regarding drug resistance in dermatophytes, but it is suggested that the resistance is on the rise. 5,21,30 In addition, only few reports revealed a correlation between in vitro resistance and therapeutic failure in dermatophyte infections.…”

“…11,[13][14][15] Although transmissions onto a human by a zoophilic species cause acute mycoses with strongly expressed symptoms of inflammatory response, 2,16 dermatophytosis spread by zoophilic agents often responds very well to antifungal drugs. 17,18 Nevertheless, frequent treatment failures and side effects have been reported in patients receiving immunosuppressive therapy, affected by diabetes mellitus, or those with inherited caspase recruitment domain family member 9 (CARD9) deficiency. 3,19 Dermatophytosis can be treated with topical application as well as systemic administration of antifungal drugs.…”