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.

Mucormycosis at a tertiary-care center in Mexico. A 35-year retrospective study of 214 cases.

BACKGROUND: Mucormycosis is a rare, invasive disease associated with high mortality rates, produced by opportunistic pathogens related to the Mucorales order and characterised by a diverse range of clinical forms; acute rhino-orbital-cerebral and pulmonary symptoms are the most reported ones. OBJECTIVES: To report the experience of mucormycosis observed in a tertiary-care hospital in Mexico for 35 years. METHODS: This was a retrospective, descriptive and observational study on mucormycosis at a tertiary-care hospital in Mexico from January 1985 to December 2019. Demographic and clinical data and mycological and histopathological records were selected. RESULTS: Two hundred fourteen proven cases of mucormycosis for 35 years at a tertiary-care hospital in Mexico were included. Most of the cases were male patients with a median age of 45 years. The two most associated underlying diseases were diabetes mellitus (76.6%) and haematologic malignancy (15.4%). The three primary clinical forms were as follows: rhino-orbito-cerebral (75.9%), cutaneous (8.41%) and pulmonary (7.47%) mucormycosis. The most isolated agents were Rhizopus arrhizus (58.4%) and Lichtheimia corymbifera (12.3%). The overall therapeutic response was 58.5%, and the best response was observed with amphotericin B deoxycholate and surgical debridement. CONCLUSION: Mucormycosis is an emerging disease, and its incidence has increased at our hospital over the years. In this study, the rhino-cerebral clinical type was the most frequent in patients with uncontrolled diabetes; the main aetiological agent was R. arrhizus. Early diagnosis, control of the underlying disease and prompt management may increase the survival rate.

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.

Development of an immunocompetent murine model of pulmonary infection due to Scedosporium apiospermum.

A pulmonary infection model due to Scedosporium apiospermum in immunocompetent mice was developed. BALB/c mice were infected by endotracheal intubation with 5 × 106 conidia/mouse and disease progression was evaluated on days 1, 3, 5, 7, 11, 16, 21, 30, 50 and 60 post-infection through quantitative culture and histopathological analysis of lungs, livers, spleens, brains, and kidneys. There was no extrapulmonary dissemination during the study nor shown to be a lethal infection. The fungal burden in lungs was maintained from day 1-5 and gradually decreased by day 30 post-challenge. On day 60, 30% of mice showed complete elimination of the fungus. Severe alterations in the lung tissue were observed, as well as the presence of conidia and hyphae surrounded by a cellular infiltrate composed mainly of neutrophils in the first days of the infection. The elimination of fungal cells and normal tissue morphology were recovered throughout the study.

The BPtpA protein from Burkholderia cenocepacia belongs to a new subclass of low molecular weight protein tyrosine phosphatases.

Low molecular weight protein tyrosine phosphatases (LMW-PTP) are ubiquitous enzymes found across a spectrum of genera from prokaryotes to higher eukaryotes. LMW-PTP belong to the Cys-based PTP class II protein family. Here, we show that LMW-PTP can be categorized into two different groups, referred as class II subdivision I (class II.I) and subdivision II (class II.II). Using BPtpA from the opportunistic pathogen Burkholderia cenocepacia, as a representative member of the LMW-PTP class II.I, we demonstrated that four conserved residues (W47, H48, D80, and F81) are required for enzyme function. Guided by an in silico model of BPtpA, we show that the conserved residues at α3-helix (D80 and F81) contribute to protein stability, while the other conserved residues in the W-loop (W47 and H48) likely play a role in substrate recognition. Overall, our results provide new information on LMW-PTP protein family and establish B. cenocepacia as a suitable model to investigate how substrates are recognized and sorted by these proteins.

Evaluation of the expanding spectrum of sertraline against uncommon fungal pathogens.

The emergence of non-Aspergillus mold pathogens has increased notoriously in the last decades with serious health consequences. The options of treatment for these microorganisms often resistant to a wide variety of antifungals is limited. Sertraline is an antidepressant with in vitro and in vivo antifungal properties which has been recently studied as an adjuvant in the treatment of invasive infections. In this study, we evaluated the in vitro interaction of sertraline with voriconazole and amphotericin B against Lomentospora prolificans, Scedosporium spp., Fusarium spp., Paecilomyces spp., Alternaria spp. and Curvularia spp. The minimum inhibitory concentration and minimum fungicidal concentration for sertraline were in the range of 8-32 µg/mL. Sertraline showed antifungal capacity against all fungi tested and synergism in combination with amphotericin B against some strains of Lomentospora prolificans, Scedosporium apiospermum and Alternaria alternata, antagonism with voriconazole against Purpureocillium lilacinum and indifference in both combinations for most of the other strains tested. These results suggest a potential role of sertraline as an adjuvant in the treatment of some of these serious mycoses.

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 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.

Clinical evaluation of the antifungal effect of sertraline in the treatment of cryptococcal meningitis in HIV patients: a single Mexican center experience.

PURPOSE: Cryptococcal meningitis is a potentially fatal fungal infection associated with a significant attributable morbidity and mortality, especially among HIV/AIDS patients. The first-line therapy for the treatment of this clinical entity is the combinatory therapy of amphotericin B plus flucytosine. However, the high cost, toxic effects, and limited repertoire of effective antifungal drugs have led to the investigation of novel molecules. This is a prospective, double-blinded, and randomized study performed in a Mexican tertiary care center to evaluate the antifungal activity of sertraline in the treatment of cryptococcal meningitis in HIV patients. METHODS: During June 2015-December 2016, patients were recruited and included in one of two study groups: group A was given standard antifungal treatment plus sertraline 200 mg/day, while group B was given standard antifungal plus placebo. Lumbar punctures were performed on days 0, 7, and 14 of the study, and cryptococcal antigenemia and quantitative fungal culture in cerebrospinal fluid at each time point were evaluated to measure the rate of fungal clearance. RESULTS: The fungal loads and cryptococcal antigenemia titers showed a marked tendency to decrease by day 14 in both groups. Otherwise, group B exhibited a slightly higher nonstatistical rate of fungal clearance (-0.2868 ± 0.08275 log CFU/ml/day) than group A (-0.2496 ± 0.08340 log CFU/ml/day). CONCLUSIONS: A statistical difference between study groups was not found. This is the first study in Latin America that reports the experience of using sertraline as an adjuvant in the antifungal management of cryptococcal meningitis in HIV patients.

Successful treatment of Talaromyces amestolkiae pulmonary infection with voriconazole in an acute lymphoblastic leukemia patient.

Infections due to Talaromyces spp. are uncommon, but they have been reported previously as causative agents of disease in immunocompromised patients. The prognosis of hemato-oncological patients with an invasive fungal infection is generally poor and the identification of the causative agent is usually not achieved or in some cases the isolated agent is taken as a contaminant and not treated, which contributes to their bad outcome. We report a case of Talaromyces amestolkiae pulmonary infection in an acute lymphoblastic leukemia patient, which was successfully treated with voriconazole, and discuss the importance of molecular identification and treatment of non-traditionally pathogenic fungi in this specific subset of patients.

Activity of sertraline against Cryptococcus neoformans: in vitro and in vivo assays.

Cryptococcus neoformans infection is an important cause of meningitis in HIV/AIDS endemic regions. Antifungals for its management include amphotericin B, flucytosine, and fluconazole. Recently, treatment of this mycosis with sertraline has been studied with variable clinical outcomes. The aim of the study was to assess the in vitro antifungal effect of sertraline against clinical isolates of Cryptococcus spp. as well as its in vivo activity in a murine model of cryptococcal meningoencephalitis. The in vitro susceptibility to fluconazole, amphotericin B, voriconazole and sertraline of 153 Cryptococcus spp. strains were evaluated according to CLSI procedures. Fungal tissue burden, serum antigenaemia and histopathology, together with the therapeutic efficacy of amphotericin B (3 mg/kg), fluconazole (15 mg/kg), and sertraline (3, 10, and 15 mg/kg) were evaluated in mice intracranially inoculated with one isolate of Cryptococcus neoformans. All strains were susceptible to the antifungals studied and exhibited growth inhibition with sertraline at clinically relevant concentrations. Sertraline at a dose of 15 mg/kg reduced the fungal burden in the brain and spleen with an efficacy comparable to that of fluconazole. In conclusion, sertraline exhibited an excellent in vitro-in vivo anti-cryptococcal activity, representing a possible new alternative for the clinical management of meningeal cryptococcosis.

Candida parapsilosis complex induces local inflammatory cytokines in immunocompetent mice.

Despite the increasing incidence of the Candida parapsilosis complex in the clinical setting and high mortality rates associated with disseminated infection, the host-fungus interactions regarding Candida parapsilosis sensu stricto and the closely related species C. orthopsilosis and C. metapsilosis remains blurred. In this study, we analyzed inflammatory cytokines levels and histopathology as well as fungal burden in spleen, kidney and lung of mice infected with six strains of the "psilosis" group with different enzymatic profiles. Strong interleukin 22 (IL-22) and tumor necrosis factor α (TNF-α) responses were observed in analyzed organs from infected mice (P < .0001) regardless of the species and enzymatic profile. TNF-α and IL-22 levels were related with spleen inflammation and fungal load. Fungal cells were detected only in spleen and kidney of infected mice, especially by day 2 post-challenge. The kidney showed glomerular retraction and partial destruction of renal tubules. Our data suggest that a strong inflammatory response, mainly of IL-22 and TNF-α, could be involved in Candida parapsilosis complex infection control.

Therapeutic efficacy of posaconazole in a murine model of disseminated trichosporonosis.

OBJECTIVES: To study the effect of the initiation time of posaconazole treatment from 1 to 3 days after systemic infection by Trichosporon asahii in mice. METHODS: BALB/c mice, 4-5 weeks old, were intravenously infected with 1 × 10(7) cfu/mouse of T. asahii. The onset of treatment varied from 1 to 3 days after infection. Orally administered posaconazole at 0.5, 1, 2, 5 or 10 mg/kg body weight/day was compared with orally administered fluconazole (at 10 mg/kg/day) and intraperitoneally administered amphotericin B (at 1 mg/kg) on alternating days. Livers, kidneys and spleens of mice that died or survived to day 25 were removed to determine fungal tissue burdens. RESULTS: When therapy began 1 day after challenge, posaconazole at ≥ 1 mg/kg significantly prolonged survival of mice compared with that of the control group and considerably reduced the fungal tissue burden over the control group. On the other hand, when treatment was started 3 days after infection, regimens of 5 and 10 mg/kg posaconazole significantly prolonged mice survival over that of the control group and appreciably diminished the fungal load compared with untreated mice. In this model, as the severity of trichosporonosis increased, higher doses of posaconazole were required to achieve equivalent activity levels. Fluconazole and amphotericin B were ineffective in preventing mice death and in significantly reducing fungal tissue burden. Posaconazole displayed potent in vivo activity against the strain tested. CONCLUSIONS: Posaconazole may be a suitable option in the treatment of disseminated T. asahii infection.

Evaluation of in vivo pathogenicity of Candida parapsilosis, Candida orthopsilosis, and Candida metapsilosis with different enzymatic profiles in a murine model of disseminated candidiasis.

Six isolates of the Candida parapsilosis complex with different enzymatic profiles were used to induce systemic infection in immunocompetent BALB/c mice. Fungal tissue burden was determined on days 2, 5, 10, and 15 post challenge. The highest fungal load irrespective of post-infection day was detected in the kidney, followed by the spleen, lung, and liver, with a tendency for the fungal burden to decrease by day 15 in all groups. Significant differences among the strains were not detected, suggesting that the three species of the "psilosis" group possess a similar pathogenic potential in disseminated candidiasis regardless of their enzymatic profiles.

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 of bloodstream fungal isolates in paediatric patients in Mexico: a nationwide surveillance study.

OBJECTIVES: To establish the species distribution and in vitro susceptibilities of 358 bloodstream fungal isolates from paediatric patients in Mexico. METHODS: Isolates were collected during a 2 year surveillance programme in 14 medical centres in 10 Mexican states. A molecular approach was used to determine the Candida parapsilosis species complex. In vitro susceptibility to amphotericin B, fluconazole, voriconazole, itraconazole, posaconazole, caspofungin, anidulafungin and micafungin was determined according to CLSI procedures. Species-specific clinical breakpoints for fluconazole, voriconazole and echinocandins were applied. RESULTS: Candida spp. accounted for 98.33% of fungaemias, including 127 Candida albicans isolates, 127 C. parapsilosis complex isolates (121 C. parapsilosis sensu stricto, 4 Candida orthopsilosis and 2 Candida metapsilosis strains) and 72 Candida tropicalis isolates. C. albicans and C. parapsilosis complex were the species predominant in neonates (48 cases each; 41.02%). C. parapsilosis complex was also the predominant species in patients 1 month to <2 years of age (P = 0.007). In contrast, C. albicans was the most frequent species in patients aged 2 to <12 years (P = 0.003). Antifungal resistance was rare among the subset of isolates. Candida glabrata showed the highest resistance rate to amphotericin B (1/9 isolates), fluconazole (1/9 isolates) and itraconazole (2/9 isolates). CONCLUSIONS: The species distribution differed with the age of the patients, with C. albicans and C. parapsilosis complex being the most commonly isolated species. C. glabrata showed the highest resistance rate to amphotericin B, fluconazole and itraconazole. This is the first study of fungaemia episodes in Mexican children.

Aspartyl proteinase, phospholipase, esterase and hemolysin activities of clinical isolates of the Candida parapsilosis species complex.

Candida parapsilosis is considered as an important emerging fungal pathogen and was recently found to be a complex that include three species, i.e., Candida parapsilosis sensu stricto, Candida orthopsilosis and Candida metapsilosis. The aim of this study was to determine the in vitro aspartyl proteinase, phospholipase, esterase and hemolysin activities of 65 clinical isolates of the C. parapsilosis complex, which had been previously identified by RFLP-BanI analysis. Of the enzymes evaluated, aspartyl proteinase was the least produced by the C. parapsilosis species complex. Phospholipase and esterase were strongly expressed by C. orthopsilosis (67% of isolates), while 10% and 13% of C. parapsilosis sensu stricto isolates were strong producers, respectively, of these two enzymes. In contrast, high production of both enzymes was not detected in C. metapsilosis. Hemolysin activity was significantly more abundant in C. orthopsilosis (87%) than C. parapsilosis sensu stricto (67%). Overall, C. orthopsilosis isolates were statistically associated with the production of hemolysins (P= 0.048) and phospholipases (P< 0.0001) compared to isolates of C. parapsilosis sensu stricto or C. metapsilosis. Furthermore, a statistical association was found between isolates recovered from blood and phospholipase production (P= 0.017). The distribution of isolates obtained from blood was 30% of C. parapsilosis sensu stricto, 67% of C. orthopsilosis and 20% of C. metapsilosis.

Murine model of disseminated fusariosis: evaluation of the fungal burden by traditional CFU and quantitative PCR.

Systemic disease is the most severe clinical form of fusariosis, and the treatment involves a challenge due to the refractory response to antifungals. Treatment for murine Fusarium solani infection has been described in models that employ CFU quantitation in organs as a parameter of therapeutic efficacy. However, CFU counts do not precisely reproduce the amount of cells for filamentous fungi such as F. solani. In this study, we developed a murine model of disseminated fusariosis and compared the fungal burden with two methods: CFU and quantitative PCR. ICR and BALB/c mice received an intravenous injection of 1 × 10(7) conidia of F. solani per mouse. On days 2, 5, 7, and 9, mice from each mice strain were killed. The spleen and kidneys of each animal were removed and evaluated by qPCR and CFU determinations. Results from CFU assay indicated that the spleen and kidneys had almost the same fungal burden in both BALB/c and ICR mice during the days of the evaluation. In the qPCR assay, the spleen and kidney of each mouse strain had increased fungal burden in each determination throughout the entire experiment. The fungal load determined by the qPCR assay was significantly greater than that determined from CFU measurements of tissue. qPCR could be considered as a tool for quantitative evaluation of fungal burden in experimental disseminated F. solani infection.

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.

Molecular characterization and antifungal susceptibility of the Candida parapsilosis species complex of clinical isolates from Monterrey, Mexico.

Recently, it was proposed that the opportunistic yeast pathogen Candida parapsilosis was a complex composed of the following three species: Candida parapsilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis. A set of 344 clinical isolates of Candida parapsilosis from Monterrey, Mexico was re-identified by RFLP. Their antifungal susceptibility to fluconazole, caspofungin, anidulafungin and micafungin was determined using the Clinical and Laboratory Standards Institute M27-A3 protocol. Candida parapsilosis sensu stricto was the most frequent species, and was the only one which showed resistance to antifungals.