Epidemiology of coccidioidomycosis in Argentina, an update.

The National Reference Laboratory in Clinical Mycology of Argentina conducted a retrospective review of human coccidioidomycosis cases diagnosed by the National Mycology Laboratory Network of Argentina between 2010 and 2022 to determine the burden of the disease in the country. A total of 100 human coccidioidomycosis cases were documented, with a higher prevalence in male patients (male-to-female ratio of 1.9:1), with a median age of 41 years. Comparing the number of cases between two 10-year periods (2000-2009 and 2010-2019), the increase was 36.51% (from 63 to 86 cases). Among the 100 recorded cases, 79 tested positive using the double immunodiffusion test. Spherules were observed in 19 cases through histopathology or direct microscopic examination and the fungus was isolated in 39 cases. Thirty-six isolates were identified as Coccidioides posadasii through partial sequencing of the Ag2/PRA gene. Catamarca province had the highest number of cases, comprising 64% of the total, with an incidence rate above 1.0-2.5/100,000 inhabitants until 2018. However, there has been a recent downward trend in the region from 2018 to 2022. It is concerning that more than half of diagnosed cases were chronic pulmonary or disseminated forms, indicating a lack of early disease detection. To rectify this issue, it is imperative to conduct targeted training programs for healthcare personnel and enhance public awareness within the endemic area. This will contribute to a better understanding of the true burden of coccidioidomycosis and enable the implementation of appropriate sanitary control measures.

Clinical and Demographic Features of Paracoccidioidomycosis in Argentina: A Multicenter Study Analysis of 466 Cases.

Information on paracoccidioidomycosis (PCM) in Argentina is fragmented and has historically been based on estimates, supported only by a series of a few reported cases. Considering the lack of global information, a national multicentric study in order to carry out a more comprehensive analysis was warranted. We present a data analysis including demographic and clinical aspects of a historical series of 466 cases recorded over 10 years (2012-2021). Patients were aged from 1 to 89 years. The general male: female (M:F) ratio was 9.5:1 with significant variation according to the age group. Interestingly, the age range 21-30 shows an M:F ratio of 2:1. Most of the cases (86%) were registered in northeast Argentina (NEA), showing hyperendemic areas in Chaco province with more than 2 cases per 10,000 inhabitants. The chronic clinical form occurred in 85.6% of cases and the acute/subacute form occurred in 14.4% of cases, but most of these juvenile type cases occurred in northwestern Argentina (NWA). In NEA, the incidence of the chronic form was 90.6%; in NWA, the acute/subacute form exceeded 37%. Diagnosis by microscopy showed 96% positivity but antibody detection displays 17% of false negatives. Tuberculosis was the most frequent comorbidity, but a diverse spectrum of bacterial, fungal, viral, parasitic, and other non-infectious comorbidities was recorded. This national multicenter registry was launched in order to better understand the current status of PCM in Argentina and shows the two endemic zones with a highly diverse epidemiology.

Utilidad del panel Sensititre YeastOne® para detectar especies de Candida resistentes a los antifúngicos / Usefulness of the Sensititre YeastOne® panel to detect Candida species resistant to antifungal drugs

Resumen Evaluamos las concordancias interlaboratorio, esencial y categórica entre el panel Sensititre YeastOne™ y los métodos de referencia correspondientes al M27 4.a ed. (Clinical and Laboratory Standards Institute [CLSI]) y al EDef 7.3.1 (European Committee on Antifungal Susceptibility Testing [EUCAST]). Estudiamos 67 cepas de Candida de distintas muestras clí nicas y un panel de 9 cepas resistentes a fluconazol y equinocandinas. El mayor porcentaje de concordancia interlaboratorio se observó con anfotericina B (96,8%) y el menor porcen taje con voriconazol (77,2%). La caspofungina mostró un 5,8% de discrepancias muy mayores con el método de referencia del CLSI. Con el del EUCAST, el itraconazol, el posaconazol y la anidulafungina mostraron porcentajes de discrepancias mayores: el 17,6, el 18,1 y el 19,6%, respectivamente. El panel Sensititre YeastOne™ es una alternativa confiable y fácil de usar, que permite detectar especies de Candida resistentes a los antifúngicos, con algunas limitaciones para las equinocandinas. Los resultados son equiparables a los de los métodos de referencia.

Abstract We evaluated the interlaboratory agreement, the essential agreement, and the cate- gorical agreement between the Sensititre YeastOne™ panel and the reference methods M27 4th Edition of the Clinical and Laboratory Standards Institute (CLSI), and the EDef 7.3.1 of the Euro- pean Committee on Antifungal Susceptibility Testing (EUCAST). We studied 67 Candida strains isolated from different clinical samples and 9 Candida strains with resistance to fluconazole and echinocandins. The highest percentage of interlaboratory agreement was observed with amp- hotericin B (96.8%), and the lowest percentage with voriconazole (77.2%). Caspofungin showed 5.8% of very major errors when compared with the CLSI reference method. For EUCAST, itraconazole, posaconazole, and anidulafungin showed high percentages of major errors: 17.6%, 18.1%, and 19.6%, respectively. Sensititre YeastOne™ is a reliable alternative, and easy to perform for detecting Candida species resistant to antifungal drugs, with some limitations for echinocandins. Results are comparable to those of the reference methods.

[Usefulness of the Sensititre YeastOne® panel to detect Candida species resistant to antifungal drugs]. / Utilidad del panel Sensititre YeastOne® para detectar especies de Candida resistentes a los antifúngicos.

We evaluated the interlaboratory agreement, the essential agreement, and the categorical agreement between the Sensititre YeastOneTM panel and the reference methods M27 4th Edition of the Clinical and Laboratory Standards Institute (CLSI), and the EDef 7.3.1 of the European Committee on Antifungal Susceptibility Testing (EUCAST). We studied 67 Candida strains isolated from different clinical samples and 9 Candida strains with resistance to fluconazole and echinocandins. The highest percentage of interlaboratory agreement was observed with amphotericin B (96.8%), and the lowest percentage with voriconazole (77.2%). Caspofungin showed 5.8% of very major errors when compared with the CLSI reference method. For EUCAST, itraconazole, posaconazole, and anidulafungin showed high percentages of major errors: 17.6%, 18.1%, and 19.6%, respectively. Sensititre YeastOneTM is a reliable alternative, and easy to perform for detecting Candida species resistant to antifungal drugs, with some limitations for echinocandins. Results are comparable to those of the reference methods.

Fungal endophytes in Peperomia obtusifolia and their potential as inhibitors of chickpea fungal pathogens.

Chickpea (Cicer arietinum L., Fabaceae) is the second most important legume after common bean (Phaseolus vulgaris L., Fabaceae) and third in production among the legumes grains worldwide. Ascochyta blight and Fusarium wilt are among the main fungal infections which cause the major losses of chickpea crop. In this work we report the phyto-pathogen controlling properties of 24 endophyte Phomopsis/Diaporthe isolates on the chickpea fungal pathogens Ascochyta rabiei, Fusarium oxysporum and Fusarium solani. The Phomopsis/Diaporthe strains were isolated amongst a total of 62 endophytic fungi from the aerial parts of the herbaceous perennial American plant Peperomia obtusifolia (Piperaceae) along with Fusarium, Septoria, Colletotrichum, Alternaria and Roussoella genera among others. Phomopsis/Diaporthe isolates were identified as Diaporthe infecunda (12 isolates), Diaporthe sackstoni (1 isolate), Diaporthe cf. brasiliensis (4 isolates) and Phomopsis cf. tuberivora (7 isolates). All the Phomopsis/Diaporthe strains antagonized A. rabiei strain AR2 with a mean of inhibition (% I) of 86.59 ± 1.49% in dual cultures. The metabolic characterization of the Phomopsis/Diaporthe strains showed groups in three clusters which were in agreement with the taxonomic identification. Bioautographic evaluation of organic extracts showed that those of D. cf. brasiliensis and D. infecunda were better as inhibitors. Strain Po 45 was one of the most active (cluster 1, 96.87% I), and its ethyl acetate extract inhibited A. rabiei growth in a bioautographic assay until at least 10 µg/mm applied showing a specific chromatographic band as the responsible of the A. rabiei inhibition.

Development and validation of an extended database for yeast identification by MALDI-TOF MS in Argentina.

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has revolutionized the identification of microorganisms in clinical laboratories because it is rapid, relatively simple to use, accurate, and can be used for a wide number of microorganisms. Several studies have demonstrated the utility of this technique in the identification of yeasts; however, its performance is usually improved by the extension of the database. Here we developed an in-house database of 143 strains belonging to 42 yeast species in the MALDI Biotyper platform, and we validated the extended database with 388 regional strains and 15 reference strains belonging to 55 yeast species. We also performed an intra- and interlaboratory study to assess reproducibility and analyzed the use of the cutoff values of 1.700 and 2.000 to correctly identify at species level. The creation of an in-house database that extended the manufacturer's database was successful in view of no incorrect identification was introduced. The best performance was observed by using the extended database and a cutoff value of 1.700 with a sensitivity of .94 and specificity of .96. A reproducibility study showed utility to detect deviations and could be used for external quality control. The extended database was able to differentiate closely related species and it has potential in distinguishing the molecular genotypes of Cryptococcus neoformans and Cryptococcus gattii.

Accuracy of diagnostic tests to detect asymptomatic bacteriuria during pregnancy.

OBJECTIVE: A dipslide is a plastic paddle coated with agar that is attached to a plastic cap that screws onto a sterile plastic vial. Our objective was to estimate the diagnostic accuracy of the dipslide culture technique to detect asymptomatic bacteriuria during pregnancy and to evaluate the accuracy of nitrate and leucocyte esterase dipslides for screening. METHODS: This was an ancillary study within a trial comparing single-day with 7-day therapy in treating asymptomatic bacteriuria. Clean-catch midstream samples were collected from pregnant women seeking routine care. Positive and negative likelihood ratios and sensitivity and specificity for the culture-based dipslide to detect and chemical dipsticks (nitrites, leukocyte esterase, or both) to screen were estimated using traditional urine culture as the "gold standard." RESULTS: : A total of 3,048 eligible pregnant women were screened. The prevalence of asymptomatic bacteriuria was 15%, with Escherichia coli the most prevalent organism. The likelihood ratio for detecting asymptomatic bacteriuria with a positive dipslide test was 225 (95% confidence interval [CI] 113-449), increasing the probability of asymptomatic bacteriuria to 98%; the likelihood ratio for a negative dipslide test was 0.02 (95% CI 0.01-0.05), reducing the probability of bacteriuria to less than 1%. The positive likelihood ratio of leukocyte esterase and nitrite dipsticks (when both or either one was positive) was 6.95 (95% CI 5.80-8.33), increasing the probability of bacteriuria to only 54%; the negative likelihood ratio was 0.50 (95% CI 0.45-0.57), reducing the probability to 8%. CONCLUSION: A pregnant woman with a positive dipslide test is very likely to have a definitive diagnosis of asymptomatic bacteriuria, whereas a negative result effectively rules out the presence of bacteriuria. Dipsticks that measure nitrites and leukocyte esterase have low sensitivity for use in screening for asymptomatic bacteriuria during gestation. CLINICAL TRIAL REGISTRATION: ISRCTN, isrctn.org, 1196608 LEVEL OF EVIDENCE: II.

Growth inhibition of toxigenic fungi by a proteinaceous compound from Streptomyces sp. C/33-6.

A Streptomyces sp. strain named C/33-6, previously isolated from soil, presented a strong and specific antagonistic effect against toxigenic fungi. This action was attributed to a proteinaceous compound (molecular weight estimated to be 14 kDa) present in the supernatant of the culture of strain C/33-6, which was sensitive to proteinases (elastase, pronase E, proteinase K) and prolongated heat treatment (100 degrees C, for 20 min). This compound showed non-chitinolytic fungicidal activity.

Microbiological study of external otitis in Rosario City, Argentina.

Mycological and/or bacteriological studies were performed on 294 samples isolated from the external auditory control (EAC). It was observed that 185 (81.5%) of the mycological analysis were negative while 42 (18.5%) were positive with the following distribution: 22 Candida (9.7%), 15 Aspergillus (6.5%) and five associations of Aspergillus and Candida (2.2%). The bacteriological studies were negative in 52 cases (23.6%) and the frequency of the bacterial agents (75.5%) isolated were as follows: 41 Pseudomonas aeruginosa (18.6%), 24 Proteus mirabilis (10.9%), 24 Staphylococcus aureus (10.9%), and three associations of Ps. aeruginosa and Pr. mirabilis (1.4%). Pseudomonas aeruginosa, which was the most frequent bacterial species isolated, did not present associations with any fungus.

Molecular detection of Histoplasma capsulatum var. capsulatum in human clinical samples.

We developed a seminested PCR for the diagnosis of histoplasmosis that amplifies a portion of the Histoplasma capsulatum H antigen gene. This assay is highly sensitive and specific, being able to detect genomic material corresponding to less than 10 yeast cells without cross-reaction against other bacterial or fungal pathogens.