Prevalence and antifungal drug resistance of dermatophytes in the clinical samples from Pakistan

Author(s):  
Bakhtawar Usman ◽  
Abdul Rehman ◽  
Iffat Naz ◽  
Muhammad Anees

AbstractDermatophytosis is a major health problem all over the world including Pakistan. This is the first report of detection of dermatophytes and their antifungal drug resistance in the Northern and Western parts of Pakistan. A total of 154 samples were collected from different hospitals of Khyber Pakhtunkhwa, and out of them 136 samples were found positive. Tinea corporis (35%) was the most predominant type of infection followed by Tinea capitis (22%). The fungi identified in Tinea corporis infection types were identified as Trichophyton rubrum, Trichophyton mentagrophytes, Epidermophyton floccosum. The fungi identified in Tinea capitis included Trichophyton violaceum, T. mentagrophytes, Microsporum ferrugineum. The gender wise distribution showed both males (52%) and females (48%) were infected with the fungi. More cases belonged to the rural parts of the country. Age wise distribution showed that the infection was more prevalent in the children and the prevalence decreased with the increase in age. The positive samples were checked against two antifungal agents: fluconazole and nystatin. Among 136 positive samples, none of the isolates showed resistance to nystatin while 7% of the samples showed resistance to fluconazole. The resistant isolates were then identified by amplifying the 18S rRNA gene, using universal primers (ITS1, ITS4). Among the 9 resistant isolates, 5 isolates were identified as Trichophyton spp., 3 as Microsporum spp. and 1 as Epidermophyton spp.

2015 ◽  
Vol 59 (7) ◽  
pp. 4356-4359 ◽  
Author(s):  
Oliver Bader ◽  
Jana Tünnermann ◽  
Anna Dudakova ◽  
Marut Tangwattanachuleeporn ◽  
Michael Weig ◽  
...  

ABSTRACTAzole antifungal drug resistance inAspergillus fumigatusis an emerging problem in several parts of the world. Here we investigated the distribution of such strains in soils from Germany. At a general positivity rate of 12%, most prevalently, we found strains with the TR34/L98H and TR46/Y121F/T289A alleles, dispersed along a corridor across northern Germany. Comparison of the distributions of resistance alleles and genotypes between environment and clinical samples suggests the presence of local clinical clusters.


2013 ◽  
Vol 57 (10) ◽  
pp. 4769-4781 ◽  
Author(s):  
A. Forastiero ◽  
A. C. Mesa-Arango ◽  
A. Alastruey-Izquierdo ◽  
L. Alcazar-Fuoli ◽  
L. Bernal-Martinez ◽  
...  

ABSTRACTCandida tropicalisranks between third and fourth amongCandidaspecies most commonly isolated from clinical specimens. Invasive candidiasis and candidemia are treated with amphotericin B or echinocandins as first-line therapy, with extended-spectrum triazoles as acceptable alternatives.Candida tropicalisis usually susceptible to all antifungal agents, although several azole drug-resistant clinical isolates are being reported. However,C. tropicalisresistant to amphotericin B is uncommon, and only a few strains have reliably demonstrated a high level of resistance to this agent. The resistance mechanisms operating inC. tropicalisstrains isolated from clinical samples showing resistance to azole drugs alone or with amphotericin B cross-resistance were elucidated. Antifungal drug resistance was related to mutations of the azole target (Erg11p) with or without alterations of the ergosterol biosynthesis pathway. The antifungal drug resistance shownin vitrocorrelated very well with the results obtainedin vivousing the model hostGalleria mellonella. Using this panel of strains, theG. mellonellamodel system was validated as a simple, nonmammalian minihost model that can be used to studyin vitro-in vivocorrelation of antifungals inC. tropicalis. The development inC. tropicalisof antifungal drug resistance with different mechanisms during antifungal treatment has potential clinical impact and deserves specific prospective studies.


Genetics ◽  
2003 ◽  
Vol 163 (4) ◽  
pp. 1287-1298
Author(s):  
James B Anderson ◽  
Caroline Sirjusingh ◽  
Ainslie B Parsons ◽  
Charles Boone ◽  
Claire Wickens ◽  
...  

Abstract We show that mode of selection, degree of dominance of mutations, and ploidy are determining factors in the evolution of resistance to the antifungal drug fluconazole in yeast. In experiment 1, yeast populations were subjected to a stepwise increase in fluconazole concentration over 400 generations. Under this regimen, two mutations in the same two chromosomal regions rose to high frequency in parallel in three replicate populations. These mutations were semidominant and additive in their effect on resistance. The first of these mutations mapped to PDR1 and resulted in the overexpression of the ABC transporter genes PDR5 and SNQ2. These mutations had an unexpected pleiotropic effect of reducing the residual ability of the wild type to reproduce at the highest concentrations of fluconazole. In experiment 2, yeast populations were subjected to a single high concentration of fluconazole. Under this regimen, a single recessive mutation appeared in each of three replicate populations. In a genome-wide screen of ∼4700 viable deletion strains, 13 were classified as resistant to fluconazole (ERG3, ERG6, YMR102C, YMR099C, YPL056C, ERG28, OSH1, SCS2, CKA2, SML1, YBR147W, YGR283C, and YLR407W). The mutations in experiment 2 all mapped to ERG3 and resulted in the overexpression of the gene encoding the drug target ERG11, but not PDR5 and SNQ2. Diploid hybrids from experiments 1 and 2 were less fit than the parents in the presence of fluconazole. In a variation of experiment 2, haploids showed a higher frequency of resistance than diploids, suggesting that degree of dominance and ploidy are important factors in the evolution of antifungal drug resistance.


2019 ◽  
pp. 63-86
Author(s):  
Sharvari Dharmaiah ◽  
Rania A. Sherif ◽  
Pranab K. Mukherjee

2018 ◽  
Vol 62 (11) ◽  
Author(s):  
Qiannan Liu ◽  
Fan Yao ◽  
Guanglie Jiang ◽  
Min Xu ◽  
Si Chen ◽  
...  

ABSTRACT The fight against resistance to antifungal drugs requires a better understanding of the underlying cellular mechanisms. In order to gain insight into the mechanisms leading to antifungal drug resistance, we performed a genetic screen on a model organism, Schizosaccharomyces pombe, to identify genes whose overexpression caused resistance to antifungal drugs, including clotrimazole and terbinafine. We identified the phb2+ gene, encoding a highly conserved mitochondrial protein, prohibitin (Phb2), as a novel determinant of reduced susceptibility to multiple antifungal drugs. Unexpectedly, deletion of the phb2+ gene also exhibited antifungal drug resistance. Overexpression of the phb2+ gene failed to cause drug resistance when the pap1+ gene, encoding an oxidative stress-responsive transcription factor, was deleted. Furthermore, pap1+ mRNA expression was significantly increased when the phb2+ gene was overexpressed or deleted. Importantly, either overexpression or deletion of the phb2+ gene stimulated the synthesis of NO and reactive oxygen species (ROS), as measured by the cell-permeant fluorescent NO probe DAF-FM DA (4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate) and the ROS probe DCFH-DA (2′,7′-dichlorodihydrofluorescein diacetate), respectively. Taken together, these results suggest that Phb2 dysfunction results in reduced susceptibility to multiple antifungal drugs by increasing NO and ROS synthesis due to dysfunctional mitochondria, thereby activating the transcription factor Pap1 in fission yeast.


2003 ◽  
Vol 36 (Supplement_1) ◽  
pp. S31-S41 ◽  
Author(s):  
Juergen Loeffler ◽  
David A. Stevens

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