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.

[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.

Testing of In Vitro Susceptibility of Neisseria gonorrhoeae to Azithromycin: Comparison of Disk Diffusion and Reference Agar Dilution Methods.

Azithromycin in combination with ceftriaxone is recommended as the first-line treatment for uncomplicated gonorrhea in many countries. Therefore, monitoring of azithromycin susceptibility of Neisseria gonorrhoeae isolates is essential. In 2019, the Clinical and Laboratory Standards Institute (CLSI) listed the MIC breakpoint for a susceptible-only category to azithromycin, but breakpoints for disk diffusion are not yet available. In this study, we evaluated the usefulness of disk diffusion for testing the susceptibility of N. gonorrhoeae isolates to azithromycin. A total of 189 clinical isolates susceptible and nonsusceptible to azithromycin were used. Agar dilution MICs were correlated with inhibition zone diameters of azithromycin disks (15-µg) manufactured by BBL and Oxoid. In addition, an interlaboratory study involving two clinical microbiology laboratories was conducted. There was a strong correlation between disk diffusion and agar dilution for BBL disks (r = -0.74; P < 0.001) and Oxoid disks (r = -0.75; P < 0.001). Using a zone diameter breakpoint of ≥27 mm (susceptible) and ≤26 mm (nonsusceptible) yielded good separation between susceptible and nonsusceptible isolates and the least number of discrepancies. Compared to agar dilution, disk diffusion showed high agreement and kappa values of 95.2% and 0.899 (P < 0.001) for BBL disks and 96.8% and 0.933 (P < 0.001) for Oxoid disks, respectively. Major and very major discrepancies were observed in isolates with azithromycin MICs (1 and 2 µg/ml, respectively) near to the breakpoint. These data illustrate that disk diffusion could be a reliable method in clinical laboratories to test susceptibility to azithromycin in N. gonorrhoeae isolates.

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.

Comparison of the identification results of Candida species obtained by BD Phoenix™ and Maldi-TOF (Bruker Microflex LT Biotyper 3.1).

In patients with invasive fungal infections, the accurate and rapid identification of the genus Candida is of utmost importance since antimycotic sensitivity is closely related to the species. The aim of the present study was to compare the identification results of species of the genus Candida obtained by BD Phoenix™ (Becton Dickinson [BD]) and Maldi-TOF MS (Bruker Microflex LT Biotyper 3.1). A total of 192 isolates from the strain collection belonging to the Mycology Network of the Autonomous City of Buenos Aires, Argentina, were analyzed. The observed concordance was 95%. Only 10 strains (5%) were not correctly identified by the BD Phoenix™ system. The average identification time with the Yeast ID panels was 8h 22min. The BD Phoenix™ system proved to be a simple, reliable and effective method for identifying the main species of the genus Candida.

[Performance evaluation of Rapid™ Yeast Plus (Remel) system from two different culture media]. / Evaluación del rendimiento del sistema Rapid™ Yeast Plus (Remel) a partir de 2 medios de cultivo diferentes.

Within the genus Candida, Candida albicans is the most commonly isolated species from clinical samples. Due to the emergence of other species which can show a higher index of antifungal resistance, a fast identification of these species is necessary. The aim of this work was to evaluate the performance of the RapID Yeast Plus system from two different subculture media formulations: Sabouraud dextrose agar adjusted by Emmons (the medium is indicated in the equipment insert) and Sabouraud glucose agar, which is the most frequently used in Buenos Aires City laboratories. One hundred and sixty-six clinical sample strains coming from different hospitals belonging to the Mycology Network of Buenos Aires City were studied. From the obtained results, we conclude that the conditions and culture medium indicated by the manufacturer should be followed.

[Evaluation of Vitek 2 for the identification of Candida yeasts]. / Evaluación del sistema Vitek 2 para la identificación de las principales especies de levaduras del género Candida.

The aim of this investigation was to evaluate the performance of Vitek 2 YST cards (bioMérieux, Inc., Hazelwood, MO, USA) for the identification of yeasts of the genus Candida. A total of 168 isolates were analyzed and the results were compared to those of the API 20 C AUX (24%) o API ID 32 C (76%) kits (bioMérieux, Marcy L'Etoile, France). Each isolate was grown in chromogenic agar and in corn meal agar (Oxoid, UK) to observe its micromorphology. C. albicans and C. dublininesis were identified by additional biochemical and molecular tests. The agreement observed was 98.3%. Only three isolates were incorrectly identified by Vitek 2: one strain of C .tropicalis and one strain of C. krusei were identified as C. parapsilosis by YST while one strain of C. krusei was identified with low discrimination. The average time for obtaining results was 18.25 h. Vitek 2 is a simple, safe and useful system for the identification of significant Candida species.

[Evaluation of the VITEK 2 system (AST-YSO1 cards) for antifungal susceptibility testing against different Candida species]. / Evaluación de las tarjetas AST-YSO1 del sistema Vitek 2 para determinar la sensibilidad a antifúngicos de levaduras del género Candida.

The aim of this investigation was to evaluate the results of antifungal susceptibility for various Candida species using the Vitek 2 semi-automated system (AST-YSO1 cards, bioMérieux), and to compare them with those obtained by the CLSI (Clinical and Laboratory Standards Institute) broth microdilution reference method (Document M27-A3,2008). The essential agreement (EA) was > 90%, except for Candida glabrata against voriconazole (VCZ); and for Candida krusei against fluconazole (FCZ). The overall categorical agreement (CA) was > 90% when FCZ was evaluated and 89.5% at 24h and 80.7% at 48 h for VCZ. The average time for obtaining results was 15.5h. Minor errors were 7.8% at 24h and 6.1% at 48 h for FCZ, and 10.5% at 24h and 19.3% at 48 h for VCZ. There was only one very major error for FCZ against Candida parapsilosis and no major errors were observed. For amphotericin B, only three isolates showed MICs ≥ 2 µg/ml. The Vitek 2 system detected the MIC value for various Candida species and showed excellent agreement with the reference method proposed by the CLSI.

Rapid CD4 cell count determination and Cryptococcus and Histoplasma antigen detection in people living with HIV: Implementation of a package of care strategy in a pilot study, Argentina.

Objectives: Despite advancements in HIV diagnosis and treatment, advanced HIV disease (AHD) is still a significant concern worldwide, especially in countries with a high percentage of undiagnosed cases and late-stage diagnoses. Methods: A prospective pilot study was conducted in Buenos Aires, Argentina to assess the feasibility of implementing a package for people living with HIV, integrating a point-of-care clusters of differentiation (CD4) test, followed by rapid Cryptococcus and Histoplasma antigen (Ag) detection. Results: A total of 105 people living with HIV were enrolled, during June 2021 to October 2021. The VISITECT CD4 Advanced Disease Lateral Flow Assay (CD4-LFA) (Accubio) classified 98 (93%) patients with AHD. Compared with flow cytometry, the CD4-LFA performed with a high sensitivity (100%) but low specificity (19%) and limited accuracy (47%). In the 98 patients classified with AHD using the CD4-LFA, 16 tested positive for any of the rapid Ag used, including 12 patients positive for the Histoplasma Ag test and four positive for Cryptococcus Ag; all four patients with positive Cryptococcus Ag in sera and were diagnosed with meningitis. In the 30-day follow-up, one death was recorded. Conclusions: The CD4-LFA correctly classified all patients with CD4 ≤200 cells/µL by flow cytometry, but a high frequency of patients misclassified with AHD was recorded. We also observed a high prevalence of opportunistic fungal infections, as previously observed in the hospital where this pilot study was conducted; however, in contrast with those previous reports, mortality was lower. The study underscores the importance of scaling up comprehensive care strategies and collaborating with governmental and non-governmental partners to enhance access to essential diagnostic tools and treatments for people living with HIV. Further research with larger sample sizes is needed to validate these findings.

[Bordetella holmesii endocarditis in an asplenic patient]. / Endocarditis por Bordetella holmesii en un paciente asplénico.

The case of a 52-year-old female patient with a history of critical aortic stenosis, hypothyroidism and splenectomy as treatment for her Hodgkin's lymphoma is herein presented. In April 2011, the patient was admitted to the cardiology service due to global heart failure, fever and poor response to diuretic and vasodilator therapy. A transesophageal echocardiogram showed images compatible with vegetations in the aortic, pulmonary, and mitral valves. A diagnosis of infective endocarditis was made. Growth of gram-negative coccobacilli was observed in two blood culture sets. The microorganism was finally identified as Bordetella holmesii. The patient was treated with ceftriaxone 1 g every 12 hours for 28 days with favorable outcome.

Evaluation of the MALDI-TOF mass spectrometry technique for the identification of dermatophytes: Use of an extended database.

BACKGROUND: Identification of dermatophytes is usually performed through morphological analyses. However, it may be hindered due to the discovery of new species and complexes and, with some isolates, by the absence of fructification. Matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) seems to be an option for improving identification. AIMS: To develop a database (DB) for the identification of dermatophytes with MALDI-TOF MS, including 32 isolates from the Red de Micología de la Ciudad Autónoma de Buenos Aires [Mycology Network of the Autonomous City of Buenos Aires] (RMCABA) and one reference isolate (RMCABA DB), and evaluate its performance when added to the DB from the supplier, Bruker (Bruker DB). METHODS: All the isolates in the RMCABA DB were identified based on morphology and sequencing. To evaluate the performance of the extended DB (Bruker DB plus RMCABA DB), 136 clinical isolates were included. RESULTS: The percentages of identification at the species level increased from 45% to 88%, but the identification at the genus level decreased from 23% to 7%. CONCLUSIONS: MALDI-TOF MS yielded better performance in the identification of dermatophytes after including the RMCABA DB, which encompassed local isolates.

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.

[Evaluation of direct susceptibility testing from blood culture bottles. Clinical usefulness]. / Evaluación del antibiograma directo desde el frasco de hemocultivo con el sistema Vitek 2C: su utilidad en la clínica.

A prospective observational study was conducted in two hospitals of Buenos Aires city (Argentina); 191 clinically significant monomicrobial gram-negative bloodstream infections were included in the study, which combined the Bact-Alert System Blood culture machine and the Vitek 2C System. Organism identification and susceptibility results directly from blood culture bottles were compared with those obtained from cards inoculated with a standardized bacterial suspension obtained following subculture on agar. By comparing the results obtained from pure cultures with those by the Vitek 2C System as reference method, the agreement between the reference method and the direct identification from positive blood cultures was 99 %. By antimicrobial susceptibility testing, the overall categorical accuracy was 99 % (0.22 %, very major errors, 0.17 %, major errors and 0.61 %, minor errors). One hundred and eight (56,8 %) bloodstream infections were treated empirically with adequate antibiotics. After the results obtained directly from the bottles were reported, antimicrobial therapy was changed in 116 (60.7 %) of the episodes.

Hemophagocytic lymphohistiocytosis secondary to AIDS-related histoplasmosis and visceral leishmaniasis.

Hemophagocytic Lymphohistiocytosis (HLH) is a rare, highly aggressive syndrome involving dysregulated immune response. Most cases are secondary to underlying diseases including infections, autoimmune disorders and malignancies. The burden of disease of histoplasmosis and leishmaniosis associated with advanced HIV is still significant in low-and-middle income countries (LMIC). We present a case of histoplasmosis and leishmaniasis associated HLH in a man with an AIDS diagnosis.

Validation of a Lateral Flow Assay for Rapid Diagnosis of Histoplasmosis in Advanced HIV Disease, Buenos Aires, Argentina.

Histoplasmosis is a major cause of mortality in individuals with advanced human immunodeficiency virus (HIV) disease (AHD). We evaluated in patients with AHD a lateral flow assay (LFA) developed by MiraVista® Diagnostics (MVD LFA). Histoplasmosis was defined based on the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) case definitions. We also compared the results of this LFA with those obtained using a commercial enzyme immunoassay (EIA) developed by IMMY, Clarus Histoplasma GM EIA, IMMY (HGM EIA). A retrospective observational study was conducted at Hospital Juan A. Fernández, located in Buenos Aires, Argentina. The study included 48 urine specimens from patients aged >18 years with AHD. Urine specimens included 17 patients with disseminated histoplasmosis and 31 specimens from patients without evidence of histoplasmosis. Specimens were tested using the MVD LFA and the HGM EIA. The MVD LFA and the HGM EIA had similar analytical performance, with a sensitivity of 94%, specificity of 100%, positive predictive value of 100%, negative predictive value of 97%, and an accuracy of 98%. Comparison of the MVD LFA with the HGM EIA demonstrated a Kappa agreement index of 0.906. The LFA evaluated in this study had high analytical performance; it provided rapid diagnosis of histoplasmosis with minimal requirements for laboratory training, equipment, and laboratory infrastructure.

[Optimization of screening methodologies for the detection of Streptococcus agalactiae in pregnant women]. / Optimización de metodologías de cribaje para la búsqueda de Streptococcus agalactiae en embarazadas.

Streptococcus agalactiae is a significant worldwide cause of morbidity and mortality in pregnant women and their newborn infants. The objective of this work was to determine the usefulness of bioMerieux chromogenic medium chromID Strepto B (CR) for detecting S. agalactiae in pregnant women from the selective Todd-Hewitt broth (sel-THB ) against the methods proposed by the CDC . A total of 1924 swabs were analyzed, 962 from vaginal introitus and 962 rectal, belonging to 962 women in weeks 35-37 of pregnancy. The swabs were directly seeded in CR. Both swabs were later placed in sel-THB with 15 µg/ml supplement of nalidixic acid and 10 µg/ml colistin. After 24 h of incubation, subcultures in CR medium and agar containing 5% sheep blood (SBA) were performed. The prevalence found was 17.4%. Sensitivity, specificity, positive and negative predictive values of sel-THB subcultures with CR supplement and 48 h incubation were: 98.8, 100, 100 and 99.7%, respectively. The corresponding values of direct harvest of the sample were 57.8, 100, 100, and 90%, respectively. Sensitivity of sel-THB in SBA was 85%. Sel-THB subculture performance in CR was outstanding in comparison with the method proposed by the CDC.

[Presumptive identification of Candida spp. and other clinically important yeasts: usefulness of Brilliance Candida Agar]. / Identificación presuntiva de Candida spp. y de otras levaduras de importancia clínica: utilidad de Brilliance Candida Agar.

Fungal infections caused by yeasts have increased during the last decades and invasive forms represent a serious problem for human health. Candida albicans is the species most frequently isolated from clinical samples. However, other emerging yeast pathogens are increasingly responsible for mycotic infections, and some of them are resistant to some antifungal drugs. Consequently, it is necessary to have methods that can provide a rapid presumptive identification at species level. Numerous chromogenic agar media have been shown to be of value as diagnostic tools. We have compared a chromogenic medium, Brilliance Candida Agar, with CHROMagar Candida, the chromogenic medium most used in our country. A multicentre study was conducted in 16 Hospitals belonging to the Mycology Net of Buenos Aires City Government. A total of 240 yeast isolates were included in this research. The new chromogenic agar showed results very similar to those obtained with CHROMagar Candida.

[Catheter- associated bacteremia caused by Ochrobactrum anthropi]. / Bacteriemia relacionada a catéter por Ochrobactrum anthropi.

Ochrobactrum anthropi is a non-glucose fermentative, aerobic gram-negative bacillus, formerly known as Achromobacter sp or CDC group Vd. It has been isolated from the environment and from infections in usually immunocompromised human beings. The documented infections frequently involved catheter related bacteremia whereas endophthalmitis, urinary infections, meningitis, endocarditis, hepatic abscess, osteochondritis, pelvic abscess and pancreatic abscess were rarely involved. Here it is presented the case of a male patient aged 69 years with sustained hypotension, four day febrile syndrome, chill, lavish perspiration and sensorium deterioration. He had type 2 diabetes and antecedent of cerebrovascular accident. A double-lumen dialysis catheter was present due to chronic renal insufficiency. An episode of catheter-related bloodstream infection was documented by using Bact-Alert Blood Culture System and Differential-Time-to-Positivity Method for central venous catheter versus peripheral blood cultures (>120 min). Once removed, it was confirmed through Maki semi quantitative technique (>15 FCU). The microorganism was identified by API 20NE and Vitek 1 as Ochrobactrum anthropi.

[Identification of Candida yeasts: Conventional methods and MALDI-TOF MS]. / Identificación de levaduras del género Candida: los métodos convencionales frente a MALDI-TOF MS.

BACKGROUND: Invasive fungal infections are increasing, and Candida yeasts are the main cause. Species other than Candida albicans are becoming more frequent, and some of them may have variable patterns of susceptibility to antifungal agents, making it important to identify them correctly. Conventional identification methods used by most laboratories may present with drawbacks. Mass spectrometry (MALDI-TOF MS) has emerged as an alternative method. AIMS: The aim of this study was to evaluate the concordance of the identification, at species level, by conventional methods (API) and MALDI-TOF MS. METHODS: The following species and number of isolates were studied: Candida parapsilosis (28), Candida glabrata (34), Candida krusei (24), Candida tropicalis (45), Candida guilliermondii (30), C. albicans (28), Candida dubliniensis (6), Candida kefyr (1), and Candida lipolytica (1) from the strain collection of Autonomous City of Buenos Aires Mycology Network (RMCABA). The strains C. parapsilosis 22019, C. glabrata 90030, C. krusei 6258 and C. albicans 68548 from the American Type Culture Collection (ATCC) were also included. Discrepancies were resolved by genotyping. RESULTS AND CONCLUSIONS: The direct concordance between the conventional identification method and MALDI-TOF MS was 92.5% (186/201).