Molecular typing of multi-drug resistant Candida albicans isolated from the Segamat community, Malaysia

Author(s):  
Marie Andrea Laetitia Huët ◽  
Nazmul Hasan Muzahid ◽  
Chuen Zhang Lee ◽  
Calvin Bok Sun Goh ◽  
Jacky Dwiyanto ◽  
...  
2020 ◽  
Vol 46 (1) ◽  
pp. 22-28
Author(s):  
Shirin Tarafder ◽  
Md Bayzid Bin Monir

Background: To investigate the spread of specific genotypes in a defined geographical area and to determine any relationship of these genotypes with drug resistance the most essential method is molecular typing. It allows a rapid and precise species differentiation. Objective: This study was intended to observe the genotypes of XDR mycobacterium tuberculosis by determining 24 loci MIRU-VNTR analysis. Methods: To gain an insight about molecular typing of MTB and drug resistance-associated mutations in XDR-TB isolates a total of 98 multi drug resistant tuberculosis (MDR-TB) isolates collected through Xpert MTB/RIF assay. They were subjected to 2nd line (Fluoroquinolones, kanamycin, capreomycin and amikacin) drug susceptibility testing through line probe assay (LPA) in a view to detect extensively drug resistant tuberculosis (XDR-TB). Genotyping was done for XDR-TB isolates using 24 loci Mycobacterial Interspersed Repetitive Units-Variable Number of Tandem Repeats (MIRU-VNTR) using the online tool at http://www.MIRU-VNTRplus.org.. Out of 98 MDR-TB isolates 11(11.23%)  XDR-TB isolates were typed and analysed. Results: Twenty four loci MIRU-VNTR genotyping involving similarity searching and phylogenetic tree analysis revealed that six (54.60%) XDR-TB isolates belonged to Beijing strain, Other MTB strain also detected were Delhi/CAS two(18.20%), Haarlem two(18.20%) and New-1, one (9.10%) in number. Minimum spanning tree analysis showed two strain of Beijing family form a clonal complex. Beijing strains were more common among younger age group and within urban population. Beijing strains were also predominant in treatment failure patient. Only one new case of XDR-TB belongs to Delhi/CAS family. Second line mycobacterial drug resistance (MTBDRsl) detected by LPA showed the most prevalent mutations involved in Fluoroquinolones drug resistance (FQ) was Asp94Gly in gyrA gene (54.55%) in quinolone resistance determining region (QRDR) and for Injectable 2nd line Drug resistance (ISL) was A1401G, C1402T in 16S rrs gene (100%)..  All XDR-TB isolates showed resistance to Levofloxacin in 2nd line LPA but Moxifloxacin showed low level resistance to some cases. Conclusion: Molecular typing of XDR- TB isolates and pattern of drug resistance associated mutations in XDR-TB isolates in Bangladesh have not been reported previously. The result of this study highlights the need to reinforce the TB policy in Bangladesh with regard to control the spread and transmission as well as detection and treatment strategies regarding XDR-TB. Bangladesh Med Res Counc Bull 2020; 46(1): 22-28


Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5114
Author(s):  
Wei-Hsuan Lo ◽  
Fu-Sheng Deng ◽  
Chih-Jung Chang ◽  
Ching-Hsuan Lin

(1) Background: Few antifungal drugs are currently available, and drug-resistant strains have rapidly emerged. Thus, the aim of this study is to evaluate the effectiveness of the antifungal activity from a combinational treatment of chitosan with a clinical antifungal drug on Candida albicans and Candida tropicalis. (2) Methods: Minimum inhibitory concentration (MIC) tests, checkerboard assays, and disc assays were employed to determine the inhibitory effect of chitosan with or without other antifungal drugs on C. albicans and C. tropicalis. (3) Results: Treatment with chitosan in combination with fluconazole showed a great synergistic fungicidal effect against C. albicans and C. tropicalis, but an indifferent effect on antifungal activity when challenged with chitosan-amphotericin B or chitosan-caspofungin simultaneously. Furthermore, the combination of chitosan and fluconazole was effective against drug-resistant strains. (4) Conclusions: These findings provide strong evidence that chitosan in combination with fluconazole is a promising therapy against two Candida species and its drug-resistant strains.


2013 ◽  
Vol 55 (6) ◽  
pp. 385-391 ◽  
Author(s):  
Patricia de Souza Bonfim-Mendonca ◽  
Adriana Fiorini ◽  
Cristiane Suemi Shinobu-Mesquita ◽  
Lilian Cristiane Baeza ◽  
Maria Aparecida Fernandez ◽  
...  

SUMMARY Introduction: The majority of nosocomial fungal infections are caused by Candida spp. where C. albicans is the species most commonly identified. Molecular methods are important tools for assessing the origin of the yeasts isolated in hospitals. Methods: This is a study on the genetic profifiles of 39 nosocomial clinical isolates of C. albicans using two typing methods: random amplifified polymorphic DNA (RAPD) and microsatellite, two different primers for each technique were used. Results: RAPD provided 10 and 11 different profiles with values for SAB of 0.84 ± 0.126 and 0.88 ± 0.08 for primers M2 and P4, respectively. Microsatellite using two markers, CDC3 and HIS3, allowed the observation of six and seven different alleles, respectively, with combined discriminatory power of 0.91. Conclusions: Although genetic variability is clear, it was possible to identify high similarity, suggesting a common origin for at least a part of isolates. It is important to emphasize that common origin was proven from yeasts isolated from colonization (urine, catheter or endotracheal secretions) and blood culture from the same patient, indicating that the candidemia must have started from a site of colonization. The combination of RAPD and microsatellite provides a quick and efficient analysis for investigation of similarity among nosocomial isolates of C. albicans.


2015 ◽  
Vol 15 (2) ◽  
Author(s):  
Ying Li ◽  
Wenqiang Chang ◽  
Ming Zhang ◽  
Xiaobin Li ◽  
Yang Jiao ◽  
...  

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Lauren Wensing ◽  
Rebecca Shapiro ◽  
Deeva Uthayakumar ◽  
Viola Halder ◽  
Jehoshua Sharma ◽  
...  

With the emergence of antifungal resistant Candida albicans strains, the need for new antifungal drugs is critical in combating this fungal pathogen. Investigating essential genes in C. albicans is a vital step in characterizing putative antifungal drug targets. As some of these essential genes are conserved between fungal organisms, developed therapies targeting these genes have the potential to be broad range antifungals. In order to study these essential genes, classical genetic knockout or CRISPR-based approaches cannot be used as disrupting essential genes leads to lethality in the organism. Fortunately, a variation of the CRISPR system (CRISPR interference or CRISPRi) exists that enables precise transcriptional repression of the gene of interest without introducing genetic mutations. CRISPRi utilizes an endonuclease dead Cas9 protein that can be targeted to a precise location but lacks the ability to create a double-stranded break. The binding of the dCas9 protein to DNA prevents the binding of RNA polymerase to the promoter through steric hindrance thereby reducing expression. We recently published the novel use of this technology in C. albicans and are currently working on expanding this technology to large scale repression of essential genes. Through the construction of an essential gene CRISPRi-sgRNA library, we can begin to study the function of essential genes under different conditions and identify genes that are involved in critical processes such as drug tolerance in antifungal resistant background strains. These genes can ultimately be characterized as putative targets for novel antifungal drug development, or targeted as a means to sensitize drug-resistant strains to antifungal treatment.


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