Acquisition of cross-azole tolerance and aneuploidy in Candida albicans strains evolved to posaconazole

A number of in vitro studies have examined the acquisition of drug resistance to the triazole fluconazole, a first-line treatment for many Candida infections. Much less is known about posaconazole, a newer triazole. We conducted the first in vitro experimental evolution of replicates from eight diverse strains of C. albicans in a high level of the fungistatic drug posaconazole. Approximately half of the 132 evolved replicates survived 50 generations of evolution, biased towards some of the strain backgrounds. We found that although increases in drug resistance were rare, increases in drug tolerance (the slow growth of a subpopulation of cells in a level of drug above the resistance level) were common across strains. We also found that adaptation to posaconazole resulted in widespread cross-tolerance to other azole drugs. Widespread aneuploidy variation was also observed in evolved replicates from some strain backgrounds. Trisomy of chromosomes 3, 6, and R was identified in 11 of 12 whole-genome sequenced evolved SC5314 replicates. These findings document rampant evolved cross-tolerance among triazoles and highlight that increases in drug tolerance can evolve independently of drug resistance in a diversity of C. albicans strain backgrounds.

Efficacy of bakuchiol-garlic combination against virulent genes of Candida albicans

Background Polymicrobial biofilms are notorious for causing intraoral tissue destruction. Streptococcus sanguinis and Streptococcus mitis, commensals of oral cavities, have been found co-existing with C. albicans in resistant oral infections. There is an urgent need to find alternative treatment options. This study aims to assess the efficacy of garlic (G) and bakuchiol (Bk) combination against candida virulent genes and their subsequently secreted proteins. Methods In vitro single species biofilms of C. albicans, and mixed species biofilms formed in combination with streptococci were exposed to bakuchiol and garlic extract (Bk+G). Gene expression of agglutinin-like sequence (ALS1), (ALS3), adhesin-like wall proteins (HWP1) and aspartyl proteinases (SAP5) were determined using qPCR and their subsequent proteins were assessed through Western blotting. Results Virulent genes were significantly downregulated in single species biofilms when they were treated with Bk+G combination. However, Bk+G did not have significant effect on ALS1 and HWP1 gene in polymicrobial biofilms. ALS3 and SAP5 were significantly downregulated in Bk+G treated polymicrobial biofilm. Similar results were portrayed in Western blotting. Conclusion Bk+G combination exhibited antimicrobial effects against single and mixed species biofilms. The findings might provide insights for treating resistant candida infections. This combination could potentially serve as an herbal alternative to traditional antifungals following further research.

Exploration of anti EFG1 locked nucleic acid gapmers to control Candida albicans filamentation

Introduction: Antisense oligonucleotides (ASOs) have been successfully utilized to silence gene expression for the treatment of many genetic human diseases, and particularly the locked nucleic acid (LNA) chemical modification is extensively used with this propose. However, LNA-modified ASOs have never been exploited for controlling virulence genes of Candida. EFG1is an important determinant of virulence that is involved in the switch from yeast to filamentous forms in C. albicans. Thus, our main goal was to explore LNA antisense gapmers for controlling EFG1gene expression and to block C. albicans filamentation. Methods: A set of five LNA-modified gapmers were designed with different chemical modifications (phosphorothioate backbone (PS) and/or palmitoyl-2’-amino-LNA) and ASO length. The in vitro performance of the different ASOs was evaluatedon their ability to control EFG1 gene expression, by qRT-PCR, and to reduce C. albicans’ filamentation, through filaments’ enumeration by microscopy. The in vivo therapeutic potential of ASOs was assessed using a G. mellonella model of infection, through a survival assay. Results: In vitro results showed that all ASOs were able to reduce the levels of EFG1gene expression, consequently reducing the levels of C. albicans filamentation around 50%. Interestingly, in vivo tests showed that the LNA-modified gapmer with PS backbone and palmitoyl-2’-amino-LNA was more effective at preventing G. mellonella infections. Conclusions: Undeniably, this work promotes the development of a novel approach for the treatment of Candida infections based on the delivery of ASOs coupled with LNA chemical modification.

The Glucocorticoid PYED-1 Disrupts Mature Biofilms of Candida spp. and Inhibits Hyphal Development in Candida albicans

Invasive Candida infections have become a global public health problem due to the increase of Candida species resistant against antifungal therapeutics. The glucocorticoid PYED-1 (pregnadiene-11-hydroxy-16α,17α-epoxy-3,20-dione-1) has antimicrobial activity against various bacterial taxa. Consequently, it might be considered for the treatment of Candida infections. The antifungal activity of PYED-1 was evaluated against several fungal strains that were representative of the five species that causes the majority of Candida infections—namely, Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis and Candida krusei. PYED-1 exhibited a weak antifungal activity and a fungistatic effect on all five Candida species. On the other hand, PYED-1 exhibited a good anti-biofilm activity, and was able to eradicate the preformed biofilms of all Candida species analyzed. Moreover, PYED-1 inhibited germ tube and hyphae formation of C. albicans and reduced adhesion of C. albicans to abiotic surfaces by up to 30%.

Therapeutic drug monitoring guided fluconazole therapy in a patient with cholangitis sepsis

Candida and other fungal species play an increasing role in nosocomial infections, including cholangitis and cholangiosepsis. Early diagnosis and prompt treatment are essential in successful patient outcomes. Fluconazole is an antifungal of choice in fluconazole-sensitive Candida infections. Little information is known about the fluconazole biliary excretion. Decreased tissue penetration may be one of the possible causes of treatment failure. Due to favorable pharmacokinetics, therapeutic drug monitoring of this antifungal has not been recommended routinely. In the presented case we report the successful therapeutic drug monitoring-guided fluconazole treatment in a patient with cholangitis and cholangiosepsis caused by fluconazole-sensitive Candida spp.

306. Association of Antibiotic Use and Development Secondary Infection from Clostridium difficile, Multidrug-Resistant Bacteria, and Candida in Hospitalized Patients with History of COVID-19

Background There is increasing evidence that patients hospitalized with COVID-19 receive unnecessary antibiotics. The consequences of antibiotic overuse as it relates to antimicrobial resistance and development of secondary infections remains uncertain. The objective of this study is to compare antibiotic prescription patterns in patients with a history of COVID-19 to those without a history of COVID-19 and determine if there are differences in the frequency of secondary infections from Clostridioides difficile (C. difficile), multidrug-resistant (MDR) bacteria, and candida infections. Methods This study is a single-center, retrospective cohort study of 18,757 adults hospitalized during the COVID-19 pandemic from March 1, 2020 to March 31, 2021. Patients were stratified as COVID-19 positive, throughout all hospitalizations subsequent to the date of initial positivity, or COVID-19 negative. Differences in antibiotic practice patterns between the two groups were quantified using days of therapy per 1000 patient days (DOT/1000 PD). The frequency of C. difficile infection, MDR-bacteria, and candida infections were assessed among the two groups. Results During the 12-month study period, on average, the COVID-19 positive group received 21.81% more antibiotics than COVID-19 negative patients, with up to 56.15% increase seen in the first month of the pandemic (Table 1, Figure 1) The COVID-19 positive group had an increased frequency of Candidemia (0.73% versus 0.18%, p< .00001) and decreased isolation of ESBL organisms (1.17% versus 1.87%, p< 0.01416) compared to the COVID-19 negative group. There were no significant differences in frequency of C. difficile infection, isolation of other MDR-organisms, or Candida auris between the two groups. (Table 2) Table 1. Antibiotic days of therapy in COVID-19 positive and COVID-19 negative patients. Figure 1. Antibiotic days of therapy in total cohort, COVID-19 positive, and COVID-19 negative patients. Table 2. Frequency of secondary infections in COVID-19 positive and COVID-19 negative patients Conclusion Patients with a history of COVID-19 infection received an average of 21.81% more antibiotics, have higher rates of candidemia, but lower rates of ESBL infection than those without a history of COVID-19 infection. The potential increase in antibiotic exposure could account for the increase in candidemia in patients with a history of COVID-19. Future studies include investigating the decrease in ESBL infections seen, perhaps due to receipt of broad antibiotics in COVID-19 patients that target ESBL bacteria. Disclosures Shruti K. Gohil, MD, MPH, Medline (Other Financial or Material Support, Co-Investigator in studies in which participating hospitals and nursing homes received contributed antiseptic and cleaning products)Molnycke (Other Financial or Material Support, Co-Investigator in studies in which participating hospitals and nursing homes received contributed antiseptic and cleaning products)Stryker (Sage) (Other Financial or Material Support, Co-Investigator in studies in which participating hospitals and nursing homes received contributed antiseptic and cleaning products) Susan S. Huang, MD, MPH, Medline (Other Financial or Material Support, Conducted studies in which participating hospitals and nursing homes received contributed antiseptic and cleaning products)Molnlycke (Other Financial or Material Support, Conducted studies in which participating hospitals and nursing homes received contributed antiseptic and cleaning products)Stryker (Sage) (Other Financial or Material Support, Conducted studies in which participating hospitals and nursing homes received contributed antiseptic and cleaning products)Xttrium (Other Financial or Material Support, Conducted studies in which participating hospitals and nursing homes received contributed antiseptic and cleaning products)