Genotypic diversity is independent of pathogenicity in colombian strains of Cryptococcus neoformans and Cryptococcus gattii in Galleria mellonella

82Cryptococcosis is a potentially fatal opportunistic mycosis that affects the lungs and central nervous system. It has been suggested that certain strains of C. neoformans/C. gattii may have the potential to be more virulent according to the molecular type. This study aims to investigate the association between virulence in the G. mellonella model and genotypic diversity of Colombian clinical and environmental isolates of C. neoformans/C. gattii. A total of 33 clinical and 12 environmental isolates were selected according to their geographical origin and sequence types (STs). Pathogenicity was determined using the G. mellonella model, and the cell and capsular size before and after inoculation was determined. For C. neoformans, virulence in G. mellonella revealed that death occurred on average on day 6 (p < 0.05) and that ST5C, 6C, 25C and 71C were the most virulent. In C. gattii, death occurred at 7.3 days (p < 0.05), and ST47C, 58C, 75A and 106C were the most virulent. Capsular size increased for both species after passage in G. mellonella. In conclusion, the pathogenicity of Cryptococcus strains in the G. mellonella invertebrate model is independent of molecular type or pathogenicity factor, even within the same ST, but it is possible to find variable degrees of pathogenicity

MALDI-TOF MS for the identification of bacteria from Acropora cervicornis samples with White Band Disease

White Band Disease (WBD) is one of the most harmful coral syndromes in the Caribbean, deteriorating the structure of many corals during the eighties and nineties. Since its etiology is not entirely known, the use of techniques aimed a t identifying the associated agents could provide an approach to the composition of the populations involved in the deterioration of A. cervicornis. Therefore, this research's objective was to isolate and characterize bacteria associated with WBD in A. cervicornis from hanging nurseries of Rosario and San Bernardo Corals National Natural Park, Colombia, using MALDI-TO F MS and PCR. The results showed the presence of Bacillus cereus bacteria in individuals with bleaching signs from nurseries and transplant areas on Isla Tesoro and Isla Ceiner. One of these strains sequenced and phylogenetically analyzed was closely related t o Bacillus thuringiensis, with similarities of up to 99%. The presence of B. cereus could indicate a special relationship between this microorganism and WBD. However, it is imperative to carry out more studies on identifying the bacteria associated with this disease to support these findings. © 2022 Latin American and Caribbean Consortium of Engineering Institutions. All rights reserved

The cell wall protein Ecm33 of Candida albicans is involved in chronological life span, morphogenesis, cell wall regeneration, stress tolerance, and host–cell interaction

Q2Q11-14Ecm33 is a glycosylphosphatidylinositol-anchored protein in the human pathogen Candida albicans. This protein is known to be involved in fungal cell wall integrity (CWI) and is also critical for normal virulence in the mouse model of hematogenously disseminated candidiasis, but its function remains unknown. In this work, several phenotypic analyses of the C. albicans ecm33/ecm33 mutant (RML2U) were performed. We observed that RML2U displays the inability of protoplast to regenerate the cell wall, activation of the CWI pathway, hypersensitivity to temperature, osmotic and oxidative stresses and a shortened chronological lifespan. During the exponential and stationary culture phases, nuclear and actin staining revealed the possible arrest of the cell cycle in RML2U cells. Interestingly, a “veil growth,” never previously described in C. albicans, was serendipitously observed under static stationary cells. The cells that formed this structure were also observed in cornmeal liquid cultures. These cells are giant, round cells, without DNA, and contain large vacuoles, similar to autophagic cells observed in other fungi. Furthermore, RML2U was phagocytozed more than the wild-type strain by macrophages at earlier time points, but the damage caused to the mouse cells was less than with the wild-type strain. Additionally, the percentage of RML2U apoptotic cells after interaction with macrophages was fewer than in the wild-type strain

Characterization of Actinobacterial Communities from Arauca River Sediments (Colombia) Reveals Antimicrobial Potential Presented in Low Abundant Isolates

Q3Artículo original181-194Introduction: New strategies have been arisen to set a rapid and effective screening for selection of microorganism with bioactive potential. This study suggests that combination of physicochemical pretreatments and taxonomic dereplication of microbial collections through MALDI-TOF MS, facilitates the detection of low abundance actinobacteria with potential as a source of antimicrobial agents. Material and Methods: An unstudied microbial community from a tropical river sediment in Colombian Orinoquía is described, applying an extended cultivation strategy using physicochemical pretreatments, biological screenings and taxonomic dereplication through MALDI-TOF MS approach. Results: Actinobacteria-like isolates (790) were growth and their antimicrobial activity was assessed against methicillin-resistant Staphylococcus aureus, Vancomycin-resistant Enterococcus faecium, extended-spectrum β-lactamase Klebsiella pnumoniae, and clinical isolates of Cladosporium cladosporioides and Epicoccum nigrum. Seventy-eight isolates, belonging to the Streptomycetaceae family according to 16S rDNA analysis were found to have antimicrobial activity and were categorized as low abundance actinobacteria by MALDI-TOF MS. Conclusion: The results suggest that combination of physicochemical pretreatments and taxonomic dereplication of microbial collections through MALDI-TOF MS, facilitates the detection of low abundance actinobacteria with potential as a source of antimicrobial agents

Invasive infections with multidrug-resistant yeast Candida auris, Colombia

Q3162-164Candida auris is an emerging multidrug-resistant fungus that causes a wide range of symptoms. We report finding 17 cases of C. auris infection that were originally misclassified but correctly identified 27.5 days later on average. Patients with a delayed diagnosis of C. auris had a 30-day mortality rate of 35.2%

Cryptic Oral Microbiota: What Is Its Role as Obstructive Sleep Apnea-Related Periodontal Pathogens?

Q2Q2Periodontitis has been commonly linked to periodontopathogens categorized in Socransky’s microbial complexes; however, there is a lack of knowledge regarding “other microorganisms” or “cryptic microorganisms”, which are rarely thought of as significant oral pathogens and have been neither previously categorized nor connected to illnesses in the oral cavity. This study hypothesized that these cryptic microorganisms could contribute to the modulation of oral microbiota present in health or disease (periodontitis and/or obstructive sleep apnea (OSA) patients). For this purpose, the presence and correlation among these cultivable cryptic oral microorganisms were identified, and their possible role in both conditions was determined. Data from oral samples of individuals with or without periodontitis and with or without OSA were obtained from a previous study. Demographic data, clinical oral characteristics, and genera and species of cultivable cryptic oral microorganisms identified by MALDI-TOF were recorded. The data from 75 participants were analyzed to determine the relative frequencies of cultivable cryptic microorganisms’ genera and species, and microbial clusters and correlations tests were performed. According to periodontal condition, dental-biofilminduced gingivitis in reduced periodontium and stage III periodontitis were found to have the highest diversity of cryptic microorganism species. Based on the experimental condition, these findings showed that there are genera related to disease conditions and others related to healthy conditions, with species that could be related to different chronic diseases being highlighted as periodontitis and OSA comorbidities. The cryptic microorganisms within the oral microbiota of patients with periodontitis and OSA are present as potential pathogens, promoting the development of dysbiotic microbiota and the occurrence of chronic diseases, which have been previously proposed to be common risk factors for periodontitis and OSA. Understanding the function of possible pathogens in the oral microbiota will require more research.https://orcid.org/0000-0003-0006-7822https://orcid.org/0000-0002-5841-3014https://orcid.org/0000-0002-8646-8725https://orcid.org/0000-0001-5576-9341https://orcid.org/0000-0002-9884-9242https://orcid.org/0000-0003-1803-9141https://orcid.org/0000-0003-1302-5429Revista Internacional - IndexadaA1N

Invasive fungal infection in immunosuppressed patients treated in a tertiary hospital

Antecedentes: las infecciones fúngicas invasivas son una causa importante de morbimortalidad mundial. El aumento en la incidencia de estas micosis se relaciona con el incremento de las condiciones de inmunosupresión. Objetivo: Describir las características demográficas y clínicas de pacientes inmunosuprimidos tratados con antifúngicos por sospecha de infecciones fúngicas invasivas en una institución de tercer nivel. Materiales y métodos: estudio descriptivo de corte transversal, en el que se incluyeron pacientes que recibieron tratamiento antifúngico durante 2012 y 2013, por sospecha de infecciones fúngicas invasivas (aspergilosis, criptococosis, histoplasmosis y mucormicosis) y condición de inmunosupresión. Resultados: se analizaron 81 pacientes, con predominio masculino (66,5%) y una media de edad de 44 años. El diagnóstico de base más frecuente fue neoplasia hematolinfoide seguido de infección por el virus de la inmunodeficiencia humana (VIH). La aspergilosis angioinvasiva (52%) y la criptococosis (28%) fueron las sospechas clínicas más frecuentes. El 43 y 85% de los pacientes tuvieron hallazgos anormales en radiografía y tomografía axial computarizada de tórax respectivamente. De aquellos con sospecha de aspergilosis, el 23% tuvo prueba de galactomanano positiva, en tanto que en aquellos con sospecha de criptococosis pulmonar, el 75% fue positivo para el antígeno capsular. El 22% de los pacientes fallecieron y el 17% requirieron estancia en UCI y soporte hemodinámico. Conclusión: es importante sospechar de forma temprana la infecciones fúngicas invasivas, así como establecer un algoritmo diagnóstico e instaurar el tratamiento antifúngico de manera anticipada para disminuir los desenlaces fatales. La dificultad en la confirmación microbiológica de las infecciones fúngicas invasivas continúa siendo una problemática local, similar a lo reportado en la literatura mundial.Artículo original10-17Background: invasive fungal infections (IFI) are a major cause of mortality and morbidity worldwide. The increased incidence of these fungal infections are associated with an increase in immunosuppressive conditions. Objective: to describe demographic and clinical characteristics of immunosuppressed patients treated with antifungals for suspected invasive fungal infection (IFI) in a tertiary hospital. Materials and methods: in this descriptive cross-sectional study, immunosuppressed patients receiving antifungal treatment during 2012 and 2013, with suspected IFI (aspergillosis, cryptococcosis, mucormicosis and histoplasmosis) were included. Results: 81 patients, predominantly men (66.5%), with a mean age of 43.8 years were analyzed. The most common underlying conditions were lymphoproliferative disorders followed by HIV infection. Angioinvasive aspergillosis (52%) and cryptococcosis (28%) were most frequently suspected. 43% and 85% of patients had abnormal findings on chest radiograph and CT, respectively. 22% of the patients died and 17% required monitoring in the ICU and hemodynamic support. Conclusion: This highlights the importance of a high index of suspicion and early diagnosis of IFI, following an algorithm that enables the timely initiation of antifungal treatment to reduce fatal outcomes. It also identifies the obstacles of getting microbiological confirmation of these pathogens; the difficulties being similar in our institution to those reported elsewhere

Pneumocystis jirovecii colonization frequency in Chronic Obstructive Pulmonary Disease (COPD) patients in Bogota, Colombia

Antecedentes : la colonización por Pneumocystis jirovecci ( P. jirovecii ) se ha postulado como causa de deterioro de la función pulmonar en pacientes con Enfermedad Pulmonar Obstructiva Crónica (EPOC). Se desconocía la frecuencia de aparición de la colonización por P. jirovencii en esa pobla- ción en Colombia. Objetivo: documentar la frecuencia de colonización por P. jirovecii en mayores de 40 años con EPOC excluyendo a los pacientes que requirieran manejo inmunosupresor y a las personas infectadas por el Virus de la Inmunodefi ciencia Humana (VIH). Materiales y métodos: se trató de un estudio de corte transversal, que contó con muestreo no probabilístico por conveniencia y selección continua de pacientes. Se realizó PCR (reacción en cadena de polimerasa) en tiempo real (rt-PCR) del esputo inducido con el Kit LighMix de P. jirovecii (Roche®-Suiza) amplifi cándose un fragmento de 244 pares de bases a partir del gen de la glicoproteína de superfi cie del hongo. Resul- tados: para una muestra de 52 pacientes en total, se documentó una frecuencia de colonización del 15,4% en todos los participantes mayores de 65 años, quienes además presentaron altos índices de sintomatología según la escala modifi cada Medical Research Council (MR Cm) y el cuestionario de evaluación de la EPOC (CAT). La mayoría de pacientes analizados se clasifi có como GOLD D (63%) en la clasifi cación por la Iniciativa Global para la EPOC. Conclusiones: la frecuencia de colonización por P. jirovecii en pacientes con EPOC detectada por rt-PCR en el esputo inducido fue del 15,4%. Este constituye el primer estudio colombiano que evalúa la frecuencia de colonización del hongo.8-16Background: Pneumocystis jirovecii colonization has been proposed as the explanation for lung function decline in patients with Chronic Obstructive Pulmonary Disease (COPD). The co- lonization frequency due to Pneumocystis jirovecii in this group of patients was yet unknown in Colombia. Objective: To document the frequency of colonization in patients over 40 years old with COPD diagnosis. The study excludes patients who require immunosuppressive treatment and who are infected with Human Immunodefi ciency Virus (HIV). Materials and methods: A cross-sectional study was held, using non-probabilistic convenience sampling with continuous patient selection. Real time PCR (rt-PCR) of P. jirovecii was performed in an induced sputum sample, the fragment of 244 base pairs from the major surface glycoprotein gene of the fungus was amplifi ed using the LighMix Kit (Roche®-Switzerland). Results: From the sample of 52 pa- tients, we found a frequency of colonization of 15.4%. All colonized patients were over 65 years old with high symptomatology levels according to the modifi ed Medical Research Council scale (MRCm), and the COPD Evaluation Test (CAT). Most of the colonized patients were classifi ed as GOLD D (63%), as rated by the Global Initiative for COPD. Conclusions: The colonization frequency due to P. jirovecii in COPD patients detected by rt-PCR in induced sputum was 15.4%. This is the fi rst study to assess the frequency of P. jirovecii colonization in Colombia

The Combination of Iron and Copper Increases Pathogenicity and Induces Proteins Related to the Main Virulence Factors in Clinical Isolates of Cryptococcus neoformans var. grubii

In fungi, metals are associated with the expression of virulence factors. However, it is unclear whether the uptake of metals affects their pathogenicity. This study aimed to evaluate the effect of iron/copper in modulating pathogenicity and proteomic response in two clinical isolates of C. neoformans with high and low pathogenicity. Methods: In both isolates, the effect of 50 µM iron and 500 µM copper on pathogenicity, capsule induction, and melanin production was evaluated. We then performed a quantitative proteomic analysis of cytoplasmic extracts exposed to that combination. Finally, the effect on pathogenicity by iron and copper was evaluated in eight additional isolates. Results: In both isolates, the combination of iron and copper increased pathogenicity, capsule size, and melanin production. Regarding proteomic data, proteins with increased levels after iron and copper exposure were related to biological processes such as cell stress, vesicular traffic (Ap1, Vps35), cell wall structure (Och1, Ccr4, Gsk3), melanin biosynthesis (Hem15, Mln2), DNA repair (Chk1), protein transport (Mms2), SUMOylation (Uba2), and mitochondrial transport (Atm1). Increased pathogenicity by exposure to metal combination was also confirmed in 90% of the eight isolates. Conclusions: The combination of these metals enhances pathogenicity and increases the abundance of proteins related to the main virulence factors

Production of recombinant trichoderma reesei cellobiohydrolase ii in a new expression system based on wickerhamomyces anomalus

Q31-7Cellulase is a family of at least three groups of enzymes that participate in the sequential hydrolysis of cellulose. Recombinant expression of cellulases might allow reducing their production times and increasing the low proteins concentrations obtained with filamentous fungi. In this study, we describe the production of Trichoderma reesei cellobiohydrolase II (CBHII) in a native strain of Wickerhamomyces anomalus. Recombinant CBHII was expressed in W. anomalus 54-A reaching enzyme activity values of up to 14.5 U L−1. The enzyme extract showed optimum pH and temperature of 5.0–6.0 and 40°C, respectively. Enzyme kinetic parameters ( of 2.73 mM and Vmax of 23.1 µM min−1) were between the ranges of values reported for other CBHII enzymes. Finally, the results showed that an enzymatic extract of W. anomalus 54-A carrying the recombinant T. reesei CBHII allows production of reducing sugars similar to that of a crude extract from cellulolytic fungi. These results show the first report on the use of W. anomalus as a host to produce recombinant proteins. In addition, recombinant T. reesei CBHII enzyme could potentially be used in the degradation of lignocellulosic residues to produce bioethanol, based on its pH and temperature activity profile