Comparative genomics for the elucidation of multidrug resistance (MDR) inCandida lusitaniae

Abstract

1Multidrug resistance (MDR) has emerged in hospitals due to the use of several agents 2 administered in combination or sequentially to the same individual. We reported earlier MDR in 3Candida lusitaniae during therapy with amphotericin B (AmB), azoles and candins. We used here 4 comparative genomic approaches between the initial susceptible isolate and 4 other isolates with 5 different MDR profiles. From a total of 18 non-synonymous SNPs (NSS) in genome comparisons 6 with the initial isolate, six could be associated with MDR. One of the SNPs occurred in a putative 7 transcriptional activator (MRR1) resulting in a V668G substitution in isolates resistant to azoles 8 and 5-fluorocytosine (5-FC). We demonstrated by gene editing that MMR1 acted by upregulation 9 of MFS7 (a multidrug transporter) in the presence of the V668G substitution. MFS7 itself 10 mediated not only azole resistance but also 5-FC resistance, which represents a novel resistance 11 mechanism for this drug class. Three other distinct NSS occurred in FKS1 (a glucan synthase that 12 is targeted by candins) in three candin-resistant isolates. Lastly, two other NSS in ERG3 and ERG4 13

Candida albicans commensalism in the oral mucosa is favoured by limited virulence and metabolic adaptation

“…This step was performed with Phusion DNA Polymerase (New England Biolabs, Ipswich, MA, USA) in the presence of 1M betaine. The PCR fragment was used to transform the isolate 101 by electroporation (Kannan et al, 2019) and under selection with nourseothricin (400 µg/ml; Werner BioAgents, Jena, Germany). After PCR verification of the first allele deletion by primers pSFS2A Dwn Chk et NRG1_Kpn (isolate DSY5577), the SAT1 marker was recycled as described (Reuss et al, 2004) to yield DSY5592.…”