Isolation of Clavispora lusitaniae from the Oral Cavity of Immunocompetent Young Adults from the North of Mexico.

The human oral cavity is normally colonized by microorganisms including bacteria, fungi, archaea, viruses and protozoa. The aim of this study was to determine the frequency of Candida spp., in de oral cavity in a group of medical students from the north of Mexico. Oral sample were obtained from 240 healthy students. The specimens were analyzed by traditional microbiology cultures and DNA sequencing. Candida spp., grew in Sabouraud dextrose agar from 57 samples and subsequently were isolated and phenotyped. The definitive identification to the species level was done by sequence analysis. The yeasts were identified as follow: 28 Clavispora lusitaniae, 20 Candida albicans, 5 Pichia kudriavzevii and 4 Candida parapsilosis. Our findings revealed that 23.75% of the healthy population has a potential pathogen in their mouth. Surprisingly, C. albicans is not the predominant yeast; instead other non-Candida species are the colonizers of the oral cavity as normal microbiota. C. lusitaniae is considered an emerging opportunistic pathogen in immunosuppressive patients. This paper pretends to highlight the presence of this yeast in the oral cavity in immunocompetent young adults. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-023-01145-x.

Dissemination of Candida auris to deep organs in neonatal murine invasive candidiasis.

Candida auris is an emerging multidrug resistant fungal pathogen, which represents a major challenge for newborns systemic infections worldwide. Management of C. auris infections is complicated due to its intrinsic antifungal resistance and the limited information available on its pathogenesis, particularly during neonatal period. In this study, we developed a murine model of C. auris neonatal invasive infection. C. auris dissemination was evaluated by fungal burden and histopathological analysis of lung, brain, liver, kidney, and spleen at different time intervals. We found fungal cells in all the analyzed tissues, neonatal liver and brain were the most susceptible tissues to fungal invasion. This model will help to better understand pathogenesis mechanisms and facilitate strategies for control and prevention of C. auris infections in newborns.

Distinct innate immune responses between sublethal and lethal models of disseminated candidiasis in newborn BALB/c mice.

Invasive candidiasis is associated with a high incidence and mortality rates in infants, especially in preterm newborns. The immunopathogenesis of the mycosis during the neonatal period is poorly understood. Although several in vivo models exist to study invasive candidiasis, the majority of studies employ distinct routes of infection and use 2 to 6 day-old mice that could be less comparable in studying candidiasis in preterm infants. In this study, by using 0-days-old mice we developed a new neonatal murine model of intravenous Candida albicans infection. Using different inoculums of Candida albicans we evaluated survival, dissemination of the fungus, frequency of CD45+ cells, and cytokine production in the liver, brain, and kidneys of newborn and adult BALB/c mice. Unexpectedly, the newborn mice infected with a low inoculum (1×105 cfu per mouse) of Candida albicans survive to the infection. Compared to adult mice, the liver and brain of newborn animals had the greatest fungal burden, fungal invasion and leukocyte infiltrate. A moderate production of TNFα, IL-1ß, IL-6 and IFNγ was detected in tissues of newborn mice infected with a non-lethal inoculum of Candida albicans. In contrast, overproduction of TNFα, IL-1ß, IL-6 and IL-10 was determined when injecting with a lethal inoculum. In agreement, flow cytometry of brain and liver showed an inoculum-dependent CD45+ leukocyte infiltration in newborn mice infected with Candida albicans. Overall, our data shows that Candida albicans infection in newborn mice affects mainly the brain and liver and a 2-fold increase of the inoculum rapidly becomes lethal probably due to massive fungal invasion and exacerbated CD45+ leukocyte infiltrate and cytokine production. This study is the first analysis of innate immune responses in different tissues during early neonatal disseminated candidiasis.

Species distribution and antifungal susceptibility patterns of Aspergillus isolates from clinical specimens and soil samples in Mexico.

This study aimed to assess the species distribution and antifungal susceptibility patterns of 200 strains of Aspergillus isolated from clinical specimens (n = 146) and soil samples (n = 54) in Mexico. ITS, ß-tubulin, and calmodulin DNA sequencing was performed for species identification. Broth microdilution susceptibility testing for amphotericin B, voriconazole, posaconazole, itraconazole, isavuconazole, anidulafungin, caspofungin, and micafungin was done according to CLSI for all strains. A. fumigatus was most frequently recovered from clinical specimens, while A. niger was commonly encountered in soil, both followed by A. flavus in the second place. A total of 60 (30%) cryptic species were identified, with A. tubingensis and A. tamarii being the most commonly found. The decreased susceptibility to amphotericin B and azoles was 32% for both, and were mainly led by A. fumigatus, whereas this percentage decreased to 9% for caspofungin, particularly in A. terreus. More than 75% of cryptic species were susceptible in vitro to all antifungals. Multi-azole decreased susceptibility was detected only in seven isolates. Given that antifungal resistance in Aspergillus spp. is an increasing worldwide threat that causes major challenges in the clinical management of aspergillosis, these data highlight the need for continuous epidemiological surveillance of these pathogens for the implementation of locally adequate treatment strategies. LAY SUMMARY: This is an epidemiological study in Mexico. A. fumigatus was most frequent in clinical specimens and A. niger in soil samples. A. tubingensis and A. tamarii were the most common cryptic species. Resistance to amphotericin B and azoles was 32% each, and 9% for caspofungin.

First case of Candida auris isolated from the bloodstream of a Mexican patient with serious gastrointestinal complications from severe endometriosis.

A 58-year-old woman was diagnosed with severe endometriosis and had multiple gastrointestinal tract complications for many years. Candida auris and C. parapsilosis were isolated from the bloodstream. Identification of C. auris was confirmed by amplification and sequencing of the internal transcriber spacer and the D1/D2 domain of the large rRNA gene subunit. Antifungal susceptibility was tested in both isolates using the Clinical Laboratory Standards Institute protocol M27-A3/S4. The patient evolved favorably with systemic antifungal therapy consisting of caspofungin and liposomal amphotericin B.

A comparative study of extracellular enzymes from chromoblastomycosis agents reveals the potential association of phospholipase with the severity of the lesions.

Chromoblastomycosis is a chronic, progressive subcutaneous mycosis that is endemic in tropical and subtropical countries. Cladophialophora carrionii and Fonsecaea pedrosoi are prevalent etiological agents. The potential role of the proteolytic activity of extracellular enzymes in these fungi and its relationship with the pathogenesis of the disease has not been proven. Some phenotypic traits have been associated with the virulence of other fungi; i.e., their different rate of protease, phospholipase, and esterase excretion, melanin, and thermotolerance. The aim of this study was the identification of extracellular enzymes that could be considered virulence markers of chromoblastomycosis agents. Therefore, we tested 29 C. carrionii and 11 F. pedrosoi clinical isolates to determine their hydrolytic and physiologic characteristics. All the tested isolates grew at a range of 30°-37 °C; except 2 strains of F. pedrosoi that grew slowly at 40 °C. We noticed that the hydrolytic capabilities of the tested isolates were positive for urea hydrolysis in almost all, while both strains were negative for DNase, hemolysin, and gelatin. C. carrionii and F. pedrosoi had phospholipase and esterase activity. These findings were similar for most isolates. All strains showed an association between phospholipase activity and moderate to severe lesions. However, only in F. pedrosoi isolates, the association remains significant. We conclude that the different enzymatic production reported here may be linked to the clinical manifestations of these pathologies. Notwithstanding, the influence of other virulence factors is not excluded.

Production of neutrophil extracellular traps (NETs) in response to Scedosporium apiospermum in a murine model of pulmonary infection.

Scedosporium apiospermum is an opportunistic emerging pathogen that can develop in both immunosuppressive and immunocompetent patients with pulmonary infections. Neutrophils are recognized as critical cells in the early response to a fungal infection through different mechanisms that eliminate or control the infection such as neutrophil extracellular traps (NETs). In this work, we investigate the presence of NETs in the lung tissue of immunocompetent mice infected with Scedosporium apiospermum. In the histopathological study the presence of filamentous basophilic material with hematoxylin-eosin and periodic acid Schiff stains suggestive of extracellular DNA was observed. We demonstrated the presence of NETs by immunofluorescence staining of extracellular DNA, myeloperoxidase, and elastase in lung tissue. Our results showed that on days 1 and 3 post-infection extracellular DNA, myeloperoxidase, and elastase correlate with areas of high concentration of cell infiltrates and fungal structures. The observation of fungal structures in the tissue decreased as did the presence of NETs by day 5 post-infection. We suggest that NETs release may play an important role in the early containment of Scedosporium apiospermum lung infection.

In vivo evaluation of the antifungal activity of sertraline against Aspergillus fumigatus.

BACKGROUND: Invasive pulmonary aspergillosis is a life-threatening fungal disease principally caused by the ubiquitous mould Aspergillus fumigatus. This clinical entity is a major cause of morbidity and mortality (principally, but not restricted to, immunocompromised individuals). A few recent reports suggest in vitro fungicidal activity of sertraline against Aspergillus spp., but this activity has not yet been investigated in vivo. OBJECTIVES: To evaluate the antifungal activity of sertraline in two in vivo models of aspergillosis. METHODS: The antifungal activity of sertraline as monotherapy at three different doses (3, 10 and 15 mg/kg) was evaluated in Galleria mellonella and in a murine model of invasive pulmonary aspergillosis. Therapeutic efficacy parameters determined were larval survival and health index score for G. mellonella, whereas pulmonary fungal burden, galactomannan and lung histopathology were assessed in the murine model. RESULTS: Sertraline treatments improved larval survival and health index score, especially at doses of 10 and 15 mg/kg. Moreover, 10 mg/kg sertraline was able to reduce pulmonary fungal burden with an efficacy comparable with that of 3 mg/kg amphotericin B and 10 mg/kg voriconazole. CONCLUSIONS: To the best of our knowledge, this is the first in vivo study that evaluates the antifungal activity of sertraline against A. fumigatus, showing a possible promising option for the adjuvant treatment of pulmonary aspergillosis.

In vitro lytic activity and antifungal susceptibility of infrequently isolated yeasts.

Non-albicans Candida species have acquired relevance in the last decades as a cause of serious disease. The virulence factors and antifungal susceptibility of these rare pathogens remain largely unrecognized. We examined a total of 50 yeast isolates corresponding to 11 different infrequently isolated yeast species for their in vitro enzymatic profile and susceptibility pattern as first-line antifungals. We found aspartyl protease activity for 100% of the isolates tested as well as variable DNAse, hemolysin, phospholipase and esterase activities. All strains had low MICs for amphotericin B and showed a variable response to fluconazole (0.125-32 µg/mL) and the echinocandins tested (0.25-> 8 µg/mL).

Cytokines profile in immunocompetent mice during Trichosporon asahii infection.

Trichosporon asahii is an opportunistic yeastlike fungus commonly associated with systemic infections in immunocompromised patients. Neutropenia is recognized as the main risk factor in infections by T. asahii; however, little is known about the cytokine response during trichosporonosis. Here, we evaluated systemic and local cytokine production and histological damage in immunocompetent mice during systemic infection with T. asahii. We found a significant increased presence of G-CSF, TNF-α, IFN-γ, and IL-6 in sera samples. High levels of G-CSF were found in organs (kidney, liver and spleen); meanwhile IL-10, IL-17A, IL-2, IL-4 and TNF-α were found in low levels. Neutrophils and fungal structures were found in early stage in analyzed organs. Our results demonstrated that T. asahii induces a systemic inflammatory response and G-CSF environment in infected organs in immunocompetent mice and neutrophil recruitment in analyzed tissue suggests the importance of these cells for fungal control.

In vivo pathogenicity of Trichosporon asahii isolates with different in vitro enzymatic profiles in an immunocompetent murine model of systemic trichosporonosis.

Trichosporon asahii is an opportunistic yeastlike fungus that colonizes the gastrointestinal and respiratory tracts and human skin. Although it is an important cause of disseminated infections by non-Candida species, there are a few reports related to its virulence factors and their possible role in in vivo pathogenicity. We developed a murine model of disseminated trichosporonosis in immunocompetent mice for the evaluation of the in vivo pathogenicity of 6 T. asahii isolates with different in vitro virulence factor profiles. Tissue fungal burden was determined on days 1, 3, 7, 15, and 25 post-challenge. Overall, the largest fungal load was detected in the kidney on the 5 experimental days, while brain, spleen, and liver displayed a comparatively low fungal count. We observed a fungal burden decrease in most experimental groups from day 15. Histological analysis showed the presence of T. asahii in tissue and a generalized inflammatory infiltrate of polymorphonuclear cells in the kidney, liver, red pulp of the spleen, and the hippocampus. Even though our isolates showed different in vitro virulence factors profiles, we did not detect relevant differences when assayed in vivo, except for a higher persistence of a protease- and biofilm-producing strain in kidney, liver, and brain.

Drugs With Anticholinergic Potential and Risk of Falls With Hip Fracture in the Elderly Patients: A Case-Control Study.

BACKGROUND/OBJECTIVE: To determine the association between the use of anticholinergic drugs and the risk of falls with hip fracture in a population older than 60 years. METHODS: A case-control study in patients older than 60 years with a diagnosis of hip fracture. All drugs dispensed during the previous 30 days were identified. Sociodemographic, clinical, pharmacological (drugs according to the Anticholinergic Risk Scale [ARS]), and polypharmacy variables were analyzed. MEASUREMENTS: Falls with hip fracture and type of drug according to the ARS. RESULTS: A total of 300 patients with hip fracture and 600 controls were included. The mean age was 81.6 ± 8.9 years, with female predominance (71.3%). The use of drugs with moderate (odds ratio [OR]: 1.97, 95% confidence interval [CI]: 1.19-3.27) or high ARS scores (OR: 1.83, 95% CI: 1.13-2.96) increased the probability of fracture. CONCLUSIONS: There was an association between the use of drugs with anticholinergic properties and the probability of hip fracture in elderly patients and it was possible to establish the level of risk.

Association between the use of benzodiazepines and opioids with the risk of falls and hip fractures in older adults.

ABSTRACTBackground:To determine the association between the use of opioids and benzodiazepines and the risk of falls with hip fracture in populations older than 65 years in Colombia. METHODS: A case-control study with patients older than 65 years with diagnosis of hip fracture. Two controls were obtained per case. The drugs dispensed in the previous 30 days were identified. Sociodemographic, diagnostic, pharmacological (opioids and benzodiazepines), and polypharmacy variables were analyzed. A logistic regression model was used to analyze the risk of fall with hip fracture while using these drugs. RESULTS: We included 287 patients with hip fractures and 574 controls. There was a female predominance (72.1%) and a mean age of 82.4 ± 8.0 years. Of the patients, 12.7% had been prescribed with opioids and 4.2% with benzodiazepines in the previous month. The adjusted multivariate analysis found that using opioids (OR:4.49; 95%CI:2.72-7.42) and benzodiazepines (OR:3.73; 95%CI:1.60-8.70) in the month prior to the event was significantly associated with a greater probability of suffering a fall with hip fracture. CONCLUSIONS: People who are taking opioids and benzodiazepines have increased risk for hip fracture in Colombia. Strategies to educate physicians regarding the pharmacology of older adults should be strengthened.

Comparative Pathogenicity of Lomentospora prolificans (Scedosporium prolificans) Isolates from Mexican Patients.

We identified 11 Lomentospora prolificans isolates recovered from Mexican patients using phenotypic and molecular characteristics. The identification of isolates was assessed by internal transcribed spacer (ITS rDNA) sequencing. In vitro susceptibility to amphotericin B, fluconazole, voriconazole, posaconazole, caspofungin, anidulafungin and micafungin was determined according to Clinical and Laboratory Standards Institute (CLSI) procedures. Three isolates (07-2239, 11-2242 and 04-2673) were used to induce systemic infection in immunocompetent ICR mice. Survival and tissue burden studies were used as markers of pathogenicity. All of the strains were resistant to every antifungal tested with MIC's for AmB (8->8 µg/ml), VRC (16->16 µg/ml), PSC (16->16 µg/ml), FLC (64->64 µg/ml) and echinocandins with MICs ≥8 µg/ml. One hundred, ninety and sixty percent of the infected mice with the strains 07-2239, 11-2242 and 04-2673 died during the study, respectively. Regarding tissue burden, the highest fungal load of the infected mice was detected in brain followed by spleen and kidney, regardless of the strain.

Genotyping, extracellular compounds, and antifungal susceptibility testing of Trichosporon asahii isolated from Mexican patients.

Trichosporon asahii is considered an opportunistic pathogen responsible for severe infections, mainly in immunocompromised patients. The aims of this study were to investigate the prevalent genotypes among 39 clinical isolates of this microorganism by sequencing the IGS1 region and to determine the in vitro production of DNAse, hemolysin, aspartyl proteinase, phospholipase and esterase, as well as the susceptibilities of the isolates to amphotericin B, anidulafungin, micafungin, caspofungin, voriconazole, posaconazole, fluconazole and 5-flucytosine. Our findings showed that genotype I was the most prevalent comprising 69.23% of the isolates. We confirmed the production of esterase for all our isolates, and report the production of DNAse and aspartyl proteinase in 84.62% and 23% of the isolates, respectively. Only one isolate of T. asahii produced hemolysin. None of the isolates showed phospholipase activity. Fifty-three percent of the T. asahii strains exhibited amphotericin B MICs ≥ 2 µg/ml. The three echinocandins evaluated yielded high MICs (≥2 µg/ml) in all isolates. Thirty-five percent of the isolates had high MICs for 5-flucytosine (≥32 µg/ml), and 97% of the isolates were susceptible to the evaluated triazoles.

Clavispora lusitaniae: From a saprophytic yeast to an emergent pathogen.

Clavispora lusitaniae has been isolated from different substrates, such as soil, water, fruit, vegetables, plants, and the gastrointestinal tract of animals and humans. However, its importance lies in being isolated from in invasive infections, particularly in pediatric patients with hematologic malignancies. It is an emerging nosocomial pathogen commonly associated with fatal prognosis in immunocompromised hosts. C. lusitaniae has attracted attention in the last decade because of resistance to amphotericin B, 5- flucytosine, and fluconazole. The adaptations of this yeast to the human host may contribute to its pathogenicity. Further study will be needed to understand C. lusitaniae's ability as a potential pathogen. This mini-review highlights the importance of the growing number of invasive disease cases caused by this yeast.

Species distribution and antifungal susceptibility profiles of clinical and environmental Fusarium isolates from Mexico: A multicenter study.

Fusarium spp. has emerged as an opportunistic etiological agent with clinical manifestations varying from localized infections to deep-seated systemic disease. It is also a phytopathogen of economic impact. There are few reports on the species diversity of this genus, and no comprehensive studies on the epidemiology nor the antifungal susceptibility of Fusarium in Mexico. The present multicentric study aims to shed light on the species distribution and antifungal susceptibility patterns of 116 strains of Fusarium isolated from clinical and environmental samples. Isolates were identified by standard phenotypic characteristics and by sequencing of the ITS (internal transcribed spacer), TEF1 (translation elongation factor 1-α), RPB2 (RNA polymerase II core subunit), and/or CAM1 (calmodulin) regions. Susceptibility tests were carried out against 15 antifungals of clinical and agricultural use. Regarding Fusarium distribution, we identified 27 species belonging to eight different species complexes. The most frequently isolated species for both clinical and environmental samples were F. falciforme (34%), F. oxysporum sensu stricto (12%), F. keratoplasticum (8%), and F. solani sensu stricto (8%). All Fusarium isolates showed minimum inhibitory concentrations (MICs) equal to or above the maximum concentration evaluated for fluconazole, 5-fluocytosine, caspofungin, micafungin, and anidulafungin. All isolates had a MIC of ≤16 µg/mL for voriconazole, with a mode of 4 µg/mL. F. verticillioides appeared to be the most susceptible to all antifungals tested.

Severe strongyloidiasis: a systematic review and meta-analysis of 339 cases.

Strongyloidiasis is a parasitosis representing a significant public health problem in tropical countries. It is often asymptomatic in immunocompetent individuals but its mortality rate increases to approximately 87% in severe forms of the disease. We conducted a systematic review, including case reports and case series, of Strongyloides hyperinfection and dissemination from 1998 to 2020 searching PubMed, EBSCO and SciELO. Cases that met the inclusion criteria of the Preferred Reported Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist were analysed. Statistical analysis was performed using Fisher's exact test and Student's t-test and a Bonferroni correction for all the significant values. A total of 339 cases were included in this review. The mortality rate was 44.83%. The presence of infectious complications, septic shock and a lack of treatment were risk factors for a fatal outcome. Eosinophilia and ivermectin treatment were associated with an improved outcome.

Physiological characterization and molecular identification of Saccharomycopsis fibuligera as the etiological agent of a skin lesion.

Routine laboratory methods are not effective in identifying cryptic species resulting in the underreporting of infections caused by non-Candida yeasts. This paper presents the physiological characteristics and antifungal susceptibility of Saccharomycopsis fibuligera 12-771, isolated from a tinea-like lesion. Isolate 12-771 was identified by ITS and D1/D2 analysis as S. fibuligera. The isolate presented an auxonogram profile similar to Candida utilis, as well as protease, esterase and hemolysin activity. MICs were of 0.25 â€‹µg/mL for amphotericin B, 1-2 â€‹µg/mL for echinocandins, and 16 â€‹µg/mL for fluconazole. This work represents the first record in America of S. fibuligera as an infectious agent.

Recent Antifungal Pipeline Developments against Candida auris: A Systematic Review.

The alarming spread and impact of multidrug-resistant Candida auris infections alongside the limited therapeutic options have prompted the development of new antifungals. These promising agents are currently in different stages of development, offering novel dosing regimens and mechanisms of action. A systematic search in MEDLINE, EMBASE, Web of Science, and Scopus up to 27 June 2022 was conducted to find relevant articles reporting data of in vitro activity and in vivo efficacy of investigational antifungals against C. auris. These included new additions to existing antifungal classes (rezafungin and opelconazole), first-in-class drugs such as ibrexafungerp, manogepix/fosmanogepix, olorofim and tetrazoles (quilseconazole, oteseconazole and VT-1598), as well as other innovative agents like ATI-2307, MGCD290 and VL-2397. From 592 articles retrieved in the primary search, 27 met the eligibility criteria. The most studied agent was manogepix/fosmanogepix (overall MIC90: 0.03 mg/L), followed by ibrexafungerp (overall MIC90: 1 mg/L) and rezafungin (overall MIC mode: 0.25 mg/L), while VT-1598 and ATI-2307 were the least explored drugs against C. auris. All these compounds demonstrated significant improvements in survival and reduction in tissue fungal burden on neutropenic animal models of candidemia due to C. auris. Continual efforts towards the discovery of new treatments against this multidrug-resistant fungus are essential.