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ABSTRACT Members of the Meyerozyma guilliermondii species complex are able to cause superficial and life-threatening systemic infections with low susceptibility to azoles and echinocandins. We tested 130 bloodstream M. guilliermondii complex isolates collected from eight Latin American medical centers over 18 years (period 1 = 2000–2008 and period 2 = 2009–2018) to investigate trends in species distribution and antifungal resistance. The isolates were identified by rDNA ITS region sequencing, and antifungal susceptibility tests were performed against fluconazole, voriconazole, anidulafungin, and amphotericin B using the CLSI microbroth method. M. guilliermondii sensu stricto (s.s.; n = 116) was the most prevalent species, followed by Meyerozyma caribbica (n = 12) and Meyerozyma carpophila (n = 2). Based on rDNA ITS identification, three clades within M. guilliermondii sensu stricto were characterized (clade 1 n = 94; clade 2 n = 19; and clade 3 n = 3). In the second period of study, we found a substantial increment in the isolation of M. caribbica (3.4% versus 13.8%; P = 0.06) and clade 2 M. guilliermondii s.s. exhibiting lower susceptibility to one or more triazoles. IMPORTANCE Yeast-invasive infections play a relevant role in human health, and there is a concern with the emergence of non-Candida pathogens causing disease worldwide. There is a lack of studies addressing the prevalence and antifungal susceptibility of different species within the M. guilliermondii complex that cause invasive infections. We evaluated 130 episodes of M. guilliermondii species complex candidemia documented in eight medical centers over 18 years. We detected the emergence of less common species within the Meyerozyma complex causing candidemia and described a new clade of M. guilliermondii with limited susceptibility to triazoles. These results support the relevance of continued global surveillance efforts to early detect, characterize, and report emergent fungal pathogens exhibiting limited susceptibility to antifungals.

Aspergillosis is a disease caused by the filamentous fungus Aspergillus spp. with a spectrum of clinical presentation that includes invasive and noninvasive forms. The invasive clinical presentation of aspergillosis most frequently affects people with compromised immune systems. In patients with oncohematologic pathology, invasive lung aspergillosis is a significant opportunistic mycosis, because it occurs frequently and has a major impact on morbidity, mortality, and high costs. The global problem of antimicrobial resistance, to which improper use of antifungals contributes, has put Aspergilus spp. in the spotlight, so it is important to generate guidelines for guidance in the proper use of antifungals in the management of invasive lung aspergillosis, to obtain better clinical outcomes and promote rational use of antifungals. This guideline contains recommendations for diagnosing and treating invasive lung aspergillosis in patients with oncohematologic disease, based on evidence and defined through a participatory process of expert consensus, for the Latin American context.

Candidemia is the predominant form of invasive candidiasis and the most frequently occurring serious fungal infection in critically ill patients in Intensive Care Units (ICU). Studies carried out in Latin America reveal a higher incidence of candidemia and higher mortality rates when compared to North America or Europe. This highlights the need to develop guidelines for correctly diagnosing and treating candidemia in critically ill patients in the ICU. These guidelines are part of the efforts to implement antifungal optimization programs in the region to obtain better clinical outcomes and promote rational antifungal use. This evidence-based clinical standard, established through expert consensus for the Latin American context, contains recommendations and algorithms for diagnosing and treating candidemia in critically ill ICU patients.

IntroductionLarger populations at risk, broader use of antibiotics and longer hospital stays have impacted on the incidence of Candida sp. bloodstream infections (CBSI).ObjectiveTo determine clinical and epidemiologic characteristics of patients with CBSI in two tertiary care reference medical institutions in Mexico City.DesignProspective and observational laboratory-based surveillance study conducted from 07/2008 to 06/2010.MethodsAll patients with CBSI were included. Identification and antifungal susceptibility were performed using CLSI M27-A3 standard procedures. Frequencies, Mann-Whitney U test or T test were used as needed. Risk factors were determined with multivariable analysis and binary logistic regression analysis.ResultsCBSI represented 3.8% of nosocomial bloodstream infections. Cumulative incidence was 2.8 per 1000 discharges (incidence rate: 0.38 per 1000 patient-days). C. albicans was the predominant species (46%), followed by C. tropicalis (26%). C. glabrata was isolated from patients with diabetes (50%), and elderly patients. Sixty-four patients (86%) received antifungals. Amphotericin-B deoxycholate (AmBD) was the most commonly used agent (66%). Overall mortality rate reached 46%, and risk factors for death were APACHE II score ≥ 16 (OR = 6.94, CI95% = 2.34-20.58, pConclusionsThe cumulative incidence rate in these centers was higher than other reports from tertiary care hospitals from Latin America. Knowledge of local epidemiologic patterns permits the design of more specific strategies for prevention and preemptive therapy of CBSI.

Malassezia species are a major part of the normal mycobiota and colonize mainly sebum-rich skin regions of the body. This group of fungi cause a variety of infections such as pityriasis versicolor, folliculitis, and fungaemia. In particular, Malassezia sympodialis and its allergens have been associated with non-infective inflammatory diseases such as seborrheic dermatitis and atopic eczema. The aim of this study was to investigate the host response to M. sympodialis on oily skin (supplemented with oleic acid) and non-oily skin using an ex vivo human skin model. Host-pathogen interactions were analyzed by SEM, histology, gene expression, immunoassays and dual species proteomics. The skin response to M. sympodialis was characterized by increased expression of the genes encoding β-defensin 3 and RNase7, and by high levels of S100 proteins in tissue. Supplementation of oleic acid onto skin was associated with direct contact of yeasts with keratinocytes and epidermal damage. In oily conditions, there was increased expression of IL18 but no expression of antimicrobial peptide genes in the skin’s response to M. sympodialis. In supernatants from inoculated skin plus oleic acid, TNFα, IL-6, and IL1-β levels were decreased and IL-18 levels were significantly increased.

Human skin fungal infections (SFIs) affect 25% of the world’s population. Most of these infections are superficial. The main limitation of current animal models of human superficial SFIs is that clinical presentation is different between the different species and animal models do not accurately reflect the human skin environment. An ex vivo human skin model was therefore developed and standardised to accurately model SFIs. In this manuscript, we report our protocol for setting up ex vivo human skin infections and report results from a primary superficial skin infection with Trichophyton rubrum, an anthropophilic fungus. The protocol includes a detailed description of the methodology to prepare the skin explants, establish infection, avoid contamination, and obtain high quality samples for further downstream analyses. Scanning electronic microscopy (SEM), histology and fluorescent microscopy were applied to evaluate skin cell viability and fungal morphology. Furthermore, we describe a broad range of assays, such as RNA extraction and qRT-PCR for human gene expression, and protein extraction from tissue and supernatants for proteomic analysis by liquid chromatography-mass spectrometry (LC-MS/MS). Non-infected skin was viable after 14 days of incubation, expressed genes and contained proteins associated with proliferative, immune and differentiation functions. The macroscopic damage caused by T. rubrum had a similar appearance to the one expected in clinical settings. Finally, using this model, the host response to T. rubrum infection can be evaluated at different levels.

In individuals with HIV/AIDS, 47% of the deaths are attributed to invasive fungal infections (IFIs), despite antiretroviral (ARV) therapy. This is a retrospective study carried out in the Hospital Regional de Alta Especialidad Oaxaca (HRAEO), southwest Mexico, where IFIs that occurred during 2016–2017 are described. A total of 55 individuals were included. Histoplasmosis (36%) and possible-IFIs in neutropenic fever (20%) were the most frequent cases, followed by cryptococcosis (14%). The HIV/AIDS subpopulation corresponded with 26 cases (47%), all from an indigenous origin. The incidence of IFIs among them was 24% (95% CI = 15–33%). The CD4+ T cells median was 35 cells/mL (IQR 12–58). Four cases (15%) of unmasking IRIS were identified, three of histoplasmosis and one coccidioidomycosis. Co-infections were found in 52% (12/23), and tuberculosis in 50% (6/12) was the most frequent. The mortality rate was 48%. The general characteristics of the HIV individuals who died were atypical pneumonia (70% vs. 9%, p = 0.01), acute kidney injury, (70% vs. 9%, p = 0.008) and ICU stay (80% vs. 9%, p = 0.002). In conclusion, IFIs are diagnosed in one out of four individuals with HIV/AIDS along with other complicated infectious conditions, leading to major complications and a high mortality rate.