Tuning sterol extraction kinetics yields a renal-sparing polyene antifungal.

Decades of previous efforts to develop renal-sparing polyene antifungals were misguided by the classic membrane permeabilization model1. Recently, the clinically vital but also highly renal-toxic small-molecule natural product amphotericin B was instead found to kill fungi primarily by forming extramembraneous sponge-like aggregates that extract ergosterol from lipid bilayers2-6. Here we show that rapid and selective extraction of fungal ergosterol can yield potent and renal-sparing polyene antifungals. Cholesterol extraction was found to drive the toxicity of amphotericin B to human renal cells. Our examination of high-resolution structures of amphotericin B sponges in sterol-free and sterol-bound states guided us to a promising structural derivative that does not bind cholesterol and is thus renal sparing. This derivative was also less potent because it extracts ergosterol more slowly. Selective acceleration of ergosterol extraction with a second structural modification yielded a new polyene, AM-2-19, that is renal sparing in mice and primary human renal cells, potent against hundreds of pathogenic fungal strains, resistance evasive following serial passage in vitro and highly efficacious in animal models of invasive fungal infections. Thus, rational tuning of the dynamics of interactions between small molecules may lead to better treatments for fungal infections that still kill millions of people annually7,8 and potentially other resistance-evasive antimicrobials, including those that have recently been shown to operate through supramolecular structures that target specific lipids9.

Metabolic reprogramming during Candida albicans planktonic-biofilm transition is modulated by the transcription factors Zcf15 and Zcf26.

Candida albicans is a commensal of the human microbiota that can form biofilms on implanted medical devices. These biofilms are tolerant to antifungals and to the host immune system. To identify novel genes modulating C. albicans biofilm formation, we performed a large-scale screen with 2,454 C. albicans doxycycline-dependent overexpression strains and identified 16 genes whose overexpression significantly hampered biofilm formation. Among those, overexpression of the ZCF15 and ZCF26 paralogs that encode transcription factors and have orthologs only in biofilm-forming species of the Candida clade, caused impaired biofilm formation both in vitro and in vivo. Interestingly, overexpression of ZCF15 impeded biofilm formation without any defect in hyphal growth. Transcript profiling, transcription factor binding, and phenotypic microarray analyses conducted upon overexpression of ZCF15 and ZCF26 demonstrated their role in reprogramming cellular metabolism by regulating central metabolism including glyoxylate and tricarboxylic acid cycle genes. Taken together, this study has identified a new set of biofilm regulators, including ZCF15 and ZCF26, that appear to control biofilm development through their specific role in metabolic remodeling.

A common vesicle proteome drives fungal biofilm development.

Extracellular vesicles mediate community interactions among cells ranging from unicellular microbes to complex vertebrates. Extracellular vesicles of the fungal pathogen Candida albicans are vital for biofilm communities to produce matrix, which confers environmental protection and modulates community dispersion. Infections are increasingly due to diverse Candida species, such as the emerging pathogen Candida auris, as well as mixed Candida communities. Here, we define the composition and function of biofilm-associated vesicles among five species across the Candida genus. We find similarities in vesicle size and release over the biofilm lifespan. Whereas overall cargo proteomes differ dramatically among species, a group of 36 common proteins is enriched for orthologs of C. albicans biofilm mediators. To understand the function of this set of proteins, we asked whether mutants in select components were important for key biofilm processes, including drug tolerance and dispersion. We found that the majority of these cargo components impact one or both biofilm processes across all five species. Exogenous delivery of wild-type vesicle cargo returned mutant phenotypes toward wild type. To assess the impact of vesicle cargo on interspecies interactions, we performed cross-species vesicle addition and observed functional complementation for both biofilm phenotypes. We explored the biologic relevance of this cross-species biofilm interaction in mixed species and mutant studies examining the drug-resistance phenotype. We found a majority of biofilm interactions among species restored the community's wild-type behavior. Our studies indicate that vesicles influence the development of protective monomicrobial and mixed microbial biofilm communities.

Life expectancy among Native Americans during the COVID-19 pandemic: estimates, uncertainty, and obstacles.

Few reliable estimates have been available for assessing the impact of the COVID-19 pandemic on mortality among Native Americans. Using deidentified publicly available data on deaths and populations by age, we estimated life expectancy for the years 2019-2022 for single-race non-Hispanic Native Americans. Life expectancy in 2022 was 67.8 years, 2.3 years higher than in 2021 but a huge 4-year loss from 2019. Although our life expectancy estimates for 2022 varied under different assumptions about racial/ethnic classification and age misreporting errors, all estimates were lower than the average for middle-income countries. Estimates of losses and gains in life expectancy were consistent across assumptions. Large reductions in COVID-19 death rates between 2021 and 2022 were largely offset by increases in rates of death from unintentional injuries (particularly drug overdoses), chronic liver disease, diabetes, and heart disease, underscoring the difficulties facing Native Americans in achieving reductions in mortality, let alone returning to levels of mortality prior to the pandemic. Serious data problems have persisted for many years, but the scarcity and inadequacy of estimates during the pandemic have underscored the urgent need for timely and accurate demographic data on the Native American population.

Integrating support persons into maternity care and associations with quality of care: a postpartum survey of mothers and support persons in Kenya.

BACKGROUND: Despite research that has shown that the presence of support persons during maternity care is associated with more respectful care, support persons are frequently excluded due to facility practices or negative attitudes of providers. Little quantitative research has examined how integrating support persons in maternity care has implications for the quality of care received by women, a potential pathway for improving maternal and neonatal health outcomes. This study aimed to investigate how integrating support persons in maternity care is associated with multiple dimensions of the quality of maternity care. METHODS: We used facility-based cross-sectional survey data from women (n = 1,138) who gave birth at six high-volume facilities in Nairobi and Kiambu counties in Kenya and their support persons (n = 606) present during the immediate postpartum period. Integration was measured by the Person-Centered Integration of Support Persons (PC-ISP) items. We investigated quality of care outcomes including person-centered care outcomes (i.e., Person-Centered Maternity Care (PCMC) and Satisfaction with care) and clinical outcomes (i.e., Implementation of WHO-recommended clinical practices). We used fractional regression with robust standard errors to estimate associations between PC-ISP and care outcomes. RESULTS: Compared to low integration, high integration (≥four woman-reported PC-ISP experiences vs. <4) was associated with multiple dimensions of quality care: 3.71%-point (95% CI: 2.95%, 4.46%) higher PCMC scores, 2.76%-point higher (95% CI: 1.86%, 3.65%) satisfaction with care scores, and 4.43%-point (95% CI: 3.52%, 5.34%) higher key clinical practices, controlling for covariates. PC-ISP indicators related to communication with providers showed stronger associations with quality of care compared to other PC-ISP sub-constructs. Some support person-reported PC-ISP experiences were positively associated with women's satisfaction and key practices. CONCLUSIONS: Integrating support persons, as key advocates for women, is important for respectful maternity care. Practices to better integrate support persons, especially improving communication between support persons with providers, can potentially improve the person-centered and clinical quality of maternity care in Kenya and other low-resource settings.

A Systematic Literature Review of Hispanic Adults' Experiences With the Emergency Medical Services System in the United States Between 2000 and 2021.

OBJECTIVE: This systematic literature review presents an overview of studies that assess the experiences of Hispanic adults with (1) activation of emergency medical services (EMS); (2) on-scene care provided by EMS personnel; (3) mode of transport (EMS vs. non-EMS) to an emergency department (ED); and (4) experiences with EMS before and during the COVID-19 pandemic. METHODS: A bibliographic database search was conducted to identify relevant studies on Ovid MEDLINE (PubMed), Web of Science, EMBASE, and CINAHL. Quantitative, mixed methods, and qualitative studies published in English or Spanish were included if they discussed Hispanic adults' experiences with EMS in the US between January 1, 2000 and December 31, 2021. The Hawker and colleagues quality assessment instrument was used to evaluate the quality of studies. RESULTS: Of the 43 included studies, 13 examined EMS activation, 13 assessed on-scene care, 22 discussed the mode of transport to an ED, and 4 described Hispanic adults' experiences with EMS during the COVID-19 pandemic. Hispanics were less likely to activate EMS (N=7), less likely to receive certain types of on-scene care (N=6), and less likely to use EMS as the mode of transport to an ED (N=13), compared with non-Hispanic Whites. During the early COVID-19 pandemic period (March to May 2020), EMS use decreased by 26.5% compared with the same months during the previous 4 years. CONCLUSIONS: The contribution of this study is its attention to Hispanic adults' experiences with the different phases of the US EMS system.

Evaluating the Accuracy of 2020 Census Block-Level Estimates in California.

In this study, we provide an assessment of data accuracy from the 2020 Census. We compare block-level population totals from a sample of 173 census blocks in California across three sources: (1) the 2020 Census, which has been infused with error to protect respondent confidentiality; (2) the California Neighborhoods Count, the first independent enumeration survey of census blocks; and (3) projections based on the 2010 Census and subsequent American Community Surveys. We find that, on average, total population counts provided by the U.S. Census Bureau at the block level for the 2020 Census are not biased in any consistent direction. However, subpopulation totals defined by age, race, and ethnicity are highly variable. Additionally, we find that inconsistencies across the three sources are amplified in large blocks defined in terms of land area or by total housing units, blocks in suburban areas, and blocks that lack broadband access.

US migration history and depressive symptoms among older mexican adults.

OBJECTIVE: To explore the association between US migration, chronic conditions (diabetes, stroke, heart attack, cancer, and hypertension), and mental health (depressive symptoms, and depression). MATERIALS AND METHODS: We assessed average changes in depressive symptom scores as well as depression over time and their link with migration experience controlling for health and sociodemographic factors among older Mexican adults (50+) using 2012, 2015, and 2018 waves of the Mexican Health and Aging Study (MHAS). RESULTS: Non-migrants had higher average depressive symptom scores and prevalence of depression (5+ score) in 2012 and 2015, but there was no significant difference in either measure in 2018 or on changes over time. CONCLUSION: Although there were no significant differences in average depressive symptoms and depression over time by migration history, this study highlights some differences in 2012 and 2015. Comparing groups across migration histories allowed the researchers to examine how life course differences impact mental health outcomes.

The Candida albicans biofilm gene circuit modulated at the chromatin level by a recent molecular histone innovation.

Histone H3 and its variants regulate gene expression but the latter are absent in most ascomycetous fungi. Here, we report the identification of a variant histone H3, which we have designated H3VCTG because of its exclusive presence in the CTG clade of ascomycetes, including Candida albicans, a human pathogen. C. albicans grows both as single yeast cells and hyphal filaments in the planktonic mode of growth. It also forms a three-dimensional biofilm structure in the host as well as on human catheter materials under suitable conditions. H3VCTG null (hht1/hht1) cells of C. albicans are viable but produce more robust biofilms than wild-type cells in both in vitro and in vivo conditions. Indeed, a comparative transcriptome analysis of planktonic and biofilm cells reveals that the biofilm circuitry is significantly altered in H3VCTG null cells. H3VCTG binds more efficiently to the promoters of many biofilm-related genes in the planktonic cells than during biofilm growth, whereas the binding of the core canonical histone H3 on the corresponding promoters largely remains unchanged. Furthermore, biofilm defects associated with master regulators, namely, biofilm and cell wall regulator 1 (Bcr1), transposon enhancement control 1 (Tec1), and non-dityrosine 80 (Ndt80), are significantly rescued in cells lacking H3VCTG. The occupancy of the transcription factor Bcr1 at its cognate promoter binding sites was found to be enhanced in the absence of H3VCTG in the planktonic form of growth resulting in enhanced transcription of biofilm-specific genes. Further, we demonstrate that co-occurrence of valine and serine at the 31st and 32nd positions in H3VCTG, respectively, is essential for its function. Taken together, we show that even in a unicellular organism, differential gene expression patterns are modulated by the relative occupancy of the specific histone H3 type at the chromatin level.

Population-level impact of adverse early life conditions on adult healthy life expectancy in low- and middle-income countries.

Evidence from theories of Developmental Origins of Health and Disease (DOHaD) suggests that experiencing adverse early life conditions subsequently leads to detrimental adult health outcomes. The bulk of empirical DOHaD literature does not consider the nature and magnitude of the impact of adverse early life conditions at the population level. In particular, it ignores the distortion of age and cohort patterns of adult health and mortality and the increased load of chronic illness and disability that ensues. In this paper, we use a microsimulation model combined with empirical estimates of incidence and prevalence of obesity, type 2 diabetes, and associated disability in low- and middle-income countries to assess the magnitude of delayed effects on adult healthy life expectancy and on compression (or expansion) of morbidity at older ages. The main goal is to determine if, in what ways, and to what extent delayed effects due to early conditions can influence cohorts' chronic illness and disability profiles.

Candida albicans biofilm-induced vesicles confer drug resistance through matrix biogenesis.

Cells from all kingdoms of life produce extracellular vesicles (EVs). Their cargo is protected from the environment by the surrounding lipid bilayer. EVs from many organisms have been shown to function in cell-cell communication, relaying signals that impact metazoan development, microbial quorum sensing, and pathogenic host-microbe interactions. Here, we have investigated the production and functional activities of EVs in a surface-associated microbial community or biofilm of the fungal pathogen Candida albicans. Crowded communities like biofilms are a context in which EVs are likely to function. Biofilms are noteworthy because they are encased in an extracellular polymeric matrix and because biofilm cells exhibit extreme tolerance to antimicrobial compounds. We found that biofilm EVs are distinct from those produced by free-living planktonic cells and display strong parallels in composition to biofilm matrix material. The functions of biofilm EVs were delineated with a panel of mutants defective in orthologs of endosomal sorting complexes required for transport (ESCRT) subunits, which are required for normal EV production in diverse eukaryotes. Most ESCRT-defective mutations caused reduced biofilm EV production, reduced matrix polysaccharide levels, and greatly increased sensitivity to the antifungal drug fluconazole. Matrix accumulation and drug hypersensitivity of ESCRT mutants were reversed by addition of wild-type (WT) biofilm EVs. Vesicle complementation showed that biofilm EV function derives from specific cargo proteins. Our studies indicate that C. albicans biofilm EVs have a pivotal role in matrix production and biofilm drug resistance. Biofilm matrix synthesis is a community enterprise; prior studies of mixed cell biofilms have demonstrated extracellular complementation. Therefore, EVs function not only in cell-cell communication but also in the sharing of microbial community resources.

Formation and characterization of biofilms formed by salt-tolerant yeast strains in seawater-based growth medium.

Yeast whole cells have been widely used in modern biotechnology as biocatalysts to generate numerous compounds of industrial, chemical, and pharmaceutical importance. Since many of the biocatalysis-utilizing manufactures have become more concerned about environmental issues, seawater is now considered a sustainable alternative to freshwater for biocatalytic processes. This approach plausibly commenced new research initiatives into exploration of salt-tolerant yeast strains. Recently, there has also been a growing interest in possible applications of microbial biofilms in the field of biocatalysis. In these complex communities, cells demonstrate higher resistance to adverse environmental conditions due to their embedment in an extracellular matrix, in which physical, chemical, and physiological gradients exist. Considering these two topics, seawater and biofilms, in this work, we characterized biofilm formation in seawater-based growth media by several salt-tolerant yeast strains with previously demonstrated biocatalytic capacities. The tested strains formed both air-liquid-like biofilms and biofilms on silicone surfaces, with Debaryomyces fabryi, Schwanniomyces etchellsii, Schwanniomyces polymorphus, and Kluyveromyces marxianus showing the highest biofilm formation. The extracted biofilm extracellular matrices mostly consisted of carbohydrates and proteins. The latter group was primarily represented by enzymes involved in metabolic processes, particularly the biosynthetic ones, and in the response to stimuli. Specific features were also found in the carbohydrate composition of the extracellular matrix, which were dependent both on the yeast isolate and the nature of formed biofilms. Overall, our findings presented herein provide a unique data resource for further development and optimization of biocatalytic processes and applications employing seawater and halotolerant yeast biofilms.Key points• Ability for biofilm formation of some yeast-halotolerant strains in seawater medium• ECM composition dependent on strain and biofilm-forming surface• Metabolic enzymes in the ECM with potential applications for biocatalysis.

Socio-economic status and the double burden of malnutrition in Cambodia between 2000 and 2014: overweight mothers and stunted children.

OBJECTIVE: The Cambodian population has experienced an increase in the proportion of stunted children who have overweight mothers during a period of rapid social and economic growth. We aimed to identify socio-economic factors associated with this household-level double burden over time. DESIGN: We used data from four Cambodia Demographic and Health Surveys from 2000 to 2014 to study the impact of socio-economic status (SES) on the link between child stunting and overweight mothers in two periods 2000-2005 v. 2010-2014. We hypothesised that SES would be a primary factor associated with this phenomenon. PARTICIPANTS: We included 14 988 children under the age of 5 years, among non-pregnant mothers aged 15-49 years of age and conducted analysis on a subsample of 1572 children with overweight mothers. SETTING: Nationally representative household survey across all regions. RESULTS: SES factors, specifically household wealth and maternal employment in service or manual occupations (in 2010-2014), are the main drivers of stunting among children of overweight mothers. Children with overweight mothers in the poorest households are more than twice as likely to be stunted than in the richest in both periods (2000-2005: adjusted OR (aOR) = 2·53, 95 % CI: 1·25, 5·13; 2010-2014: aOR = 2·61, 95 % CI: 1·43, 4·77), adjusting for other SES factors, indicating that despite decreasing income inequality, the poorest continue to bear excess risk of a double burden of malnutrition. Maternal short stature also doubled the likelihood of child stunting in both periods, which suggests intergenerational transmission of adversity and physical underdevelopment. CONCLUSIONS: Socio-economic inequalities should be addressed to reduce disparities in the household-level double burden of malnutrition.

Estimation of older-adult mortality from information distorted by systematic age misreporting.

Testing theories about human senescence and longevity demands accurate information on older-adult mortality; this is rare in low- to middle-income countries where raw data may be distorted by defective completeness and systematic age misreporting. For this reason, such populations are frequently excluded from empirical tests of mortality and longevity theories, thus limiting their reach, as they reflect only a small and selected human mortality experience. In this paper we formulate an integrated method to compute estimates of older-adult mortality when vital registration and population counts are defective due to inaccurate coverage and/or systematic age misreporting. The procedure is validated with a simulation study that identifies a strategy to compute adjustments, which, under some assumptions, performs quite well. While the paper focuses on Latin American and Caribbean countries, the method is quite general and, with additional information and some model reformulation, could be applied to other populations with similar problems.

Exploiting the vulnerable active site of a copper-only superoxide dismutase to disrupt fungal pathogenesis.

Copper-only superoxide dismutases (SODs) represent a new class of SOD enzymes that are exclusively extracellular and unique to fungi and oomycetes. These SODs are essential for virulence of fungal pathogens in pulmonary and disseminated infections, and we show here an additional role for copper-only SODs in promoting survival of fungal biofilms. The opportunistic fungal pathogen Candida albicans expresses three copper-only SODs, and deletion of one of them, SOD5, eradicated candidal biofilms on venous catheters in a rodent model. Fungal copper-only SODs harbor an irregular active site that, unlike their Cu,Zn-SOD counterparts, contains a copper co-factor unusually open to solvent and lacks zinc for stabilizing copper binding, making fungal copper-only SODs highly vulnerable to metal chelators. We found that unlike mammalian Cu,Zn-SOD1, C. albicans SOD5 indeed rapidly loses its copper to metal chelators such as EDTA, and binding constants for Cu(II) predict that copper-only SOD5 has a much lower affinity for copper than does Cu,Zn-SOD1. We screened compounds with a variety of indications and identified several metal-binding compounds, including the ionophore pyrithione zinc (PZ), that effectively inhibit C. albicans SOD5 but not mammalian Cu,Zn-SOD1. We observed that PZ both acts as an ionophore that promotes uptake of toxic metals and inhibits copper-only SODs. The pros and cons of a vulnerable active site for copper-only SODs and the possible exploitation of this vulnerability in antifungal drug design are discussed.

States with fewer criminalizing immigrant policies have smaller health care inequities between citizens and noncitizens.

BACKGROUND: In the last thirty years, major shifts in immigrant policy at national and state levels has heightened boundaries among citizens, permanent residents, and those with other statuses. While there is mounting evidence that citizenship influences immigrant health care inequities, there has been less focus on how policies that reinforce citizenship stratification may shape the extent of these inequities. We examine the extent to which the relationship between citizenship and health care inequities is moderated by state-level criminalization policies. METHODS: Taking a comparative approach, we assess how distinct criminalization policy contexts across US states are associated with inequitable access to care by citizenship status. Utilizing a data set with state-level measures of criminalization policy and individual-level measures of having a usual source of care from the National Health Interview Survey, we use mixed-effects logistic regression models to assess the extent to which inequities in health care access between noncitizens and US born citizens vary depending on states' criminalization policies. RESULTS: Each additional criminalization policy was associated with a lower odds that noncitizens in the state had a usual source of care, compared to US born citizens. CONCLUSION: Criminalization policies shape the construction of citizenship stratification across geography, such as exacerbating inequities in health care access by citizenship.

Antifungal and antioomycete activities and modes of action of isobenzofuranones isolated from the endophytic fungus Hypoxylon anthochroum strain Gseg1.

Hypoxylon species are distributed worldwide and have been isolated from different habitats. The endophyte Hypoxylon anthochroum strain Gseg1 was isolated from healthy leaves of Gliricidia sepium. A chemical study of the culture medium and mycelium organic extracts of the endophytic fungus H. anthochroum Gseg1 led to the isolation of three known isobenzofuranones, 7-hydroxy-4,6-dimethyl-3H-isobenzofuran-1-one, 1, 7-methoxy-4,6-dimethyl-3H-isobenzofuran-1-one, 2, 6-formyl-4-methyl-7-methoxy-3H-isobenzofuran-1-one, 3, and one compound was isolated for the first time as a natural product, 7-methoxy-4-methyl-3H-isobenzofuran-1-one, 4. In addition, the chemical synthesis of 1 and 2, and a derivative, 7-methoxy-6-methyl-3H-isobenzofuran-1-one, 5, was performed. The isobenzofuranones showed antifungal and antioomycete activities. Compounds 1-5 inhibited the growth of Fusarium oxysporum, Alternaria alternata, Pythium aphanidermatum, and Phytophthora capsici, in addition, 1, 2 and 5 interrupted the respiration and caused electrolyte leakage due to cell membrane damage. Compound 2 was the most active, inhibiting the growth of the four microorganisms, affecting the respiration and increasing the relative conductivity due to electrolyte leakage. Compounds 1-4 also induce morphological changes in the plant pathogens' mycelia and hyphae. These compounds could be useful for the control of plant pathogenic fungi and oomycetes of agricultural relevance.

Calloused hands, shorter life? Occupation and older-age survival in Mexico.

BACKGROUND: Inequalities in mortality are often attributed to socioeconomic differences in education level, income, and wealth. Low socioeconomic status (SES) is generally related to worse health and survival across the life course. Yet, disadvantaged people are also more likely to hold jobs requiring heavy physical labor, repetitive movement, ergonomic strain, and safety hazards. OBJECTIVE: We examine the link between primary lifetime occupation, together with education and net worth, on survival among older adults in Mexico. METHODS: We use data from four waves (2001, 2003, 2012, and 2015) of the Mexican Health and Aging Study (MHAS). We estimate age-specific mortality rates for ages 50 and over using a hazards model based on a two-parameter Gompertz function. RESULTS: Primary lifetime occupations have a stronger association with survival for women than men. Women with higher socioeconomic status have significantly lower mortality rates than lower status women, whether SES is assessed in terms of schooling, wealth, or occupation. Occupational categories are not jointly related to survival among men, even without controls for education and wealth. There are significant survival differences by wealth among men, but no disparities in mortality by education. CONCLUSIONS: Consistent with recent studies of the Mexican population, we fail to find the expected gradient in the association between some measures of SES and better survival among men. CONTRIBUTION: Our estimates extend this anomalous pattern among Mexican men to another dimension of SES, occupation. SES differentials in mortality are substantially larger for Mexican women, highlighting an important gender disparity.

APX001 Pharmacokinetic/Pharmacodynamic Target Determination against Aspergillus fumigatus in an In Vivo Model of Invasive Pulmonary Aspergillosis.

APX001, the prodrug of APX001A, is a first-in-class antifungal agent that has a potent activity against Aspergillus fumigatus The goal of current study was to determine the pharmacodynamic (PD) index and target of APX001 in an immunocompromised murine model of invasive pulmonary aspergillosis against 6 A. fumigatus isolates. Minimum effective concentration (MEC) values ranged from 0.03 to 0.06 mg/liter. Dose fractionation was performed against isolate AF293 using total doses of APX001 ranging from 81 to 768 mg/kg of body weight/day fractionated into every 3-, 6-, and 8-h regimens over a 96-h treatment duration. Efficacy was assessed by A. fumigatus quantitative PCR (qPCR) of conidial equivalents from lung homogenates. Nonlinear regression analysis using the Hill equation demonstrated that the 24-h area under the concentration-time curve (AUC)/MEC ratio was the pharmacokinetic (PK)/PD index that best correlated with efficacy (coefficient of determination [R2] = 0.79). Treatment studies with the remaining strains utilized regimens of 40 to 1,536 mg/kg of APX001 administered every 3 h for a 96-h duration. Exposure-response relationships for all strains were similar, and the median free drug AUC/MEC PK/PD targets for stasis and 1-log-kill endpoints were 47.6 and 89.4, respectively. The present studies demonstrated in vitro and in vivo APX001A/APX001 potency against A. fumigatus These results have potential relevance for clinical dose selection and evaluation of susceptibility breakpoints.

Small-Molecule Morphogenesis Modulators Enhance the Ability of 14-Helical ß-Peptides To Prevent Candida albicans Biofilm Formation.

Candida albicans is an opportunistic fungal pathogen responsible for mucosal candidiasis and systemic candidemia in humans. Often, these infections are associated with the formation of drug-resistant biofilms on the surfaces of tissues or medical devices. Increased incidence of C. albicans resistance to current antifungals has heightened the need for new strategies to prevent or eliminate biofilm-related fungal infections. In prior studies, we designed 14-helical ß-peptides to mimic the structural properties of natural antimicrobial α-peptides (AMPs) in an effort to develop active and selective antifungal compounds. These amphiphilic, cationic, helical ß-peptides exhibited antifungal activity against planktonic C. albicans cells and inhibited biofilm formation in vitro and in vivo Recent studies have suggested the use of antivirulence agents in combination with antifungals. In this study, we investigated the use of compounds that target C. albicans polymorphism, such as 1-dodecanol, isoamyl alcohol, and farnesol, to attempt to improve ß-peptide efficacy for preventing C. albicans biofilms. Isoamyl alcohol, which prevents hyphal formation, reduced the minimum biofilm prevention concentrations (MBPCs) of ß-peptides by up to 128-fold. Combinations of isoamyl alcohol and antifungal ß-peptides resulted in less than 10% hemolysis at the antifungal MBPCs. Overall, our results suggest potential benefits of combination therapies comprised of morphogenesis modulators and antifungal AMP peptidomimetics for preventing C. albicans biofilm formation.