Sporotrichosis in Argentina: clinical and epidemiological analysis

Introduction

Sporotrichosis is an implantation mycosis caused by Sporothrix spp. It is distributed worldwide and can be found in vegetation and soil. The most frequent route of infection is by trauma with elements contaminated with fungal propagules. Since domestic cats are the most affected animals and can transmit this infection to humans, sporotrichosis is considered a zoonosis. Clinical presentations include nodular lymphangitis, fixed cutaneous, pulmonary (rare), and disseminated (exceptional).

Objectives

To analyze the epidemiology of sporotrichosis in Argentina during 2010 and 2022. To describe the clinical presentation, diagnostic methods, and treatment of cases diagnosed during this period. To know the circulating genotypes and to observe possible associations with the geographic location where the infection was acquired.

Materials and methods

Analytical, retrospective, and observational study. We analyzed the medical records of patients with sporotrichosis from 12 health institutions in Argentina, between 2010 and 2022.

Results

We present 54 cases in which the most frequent clinical form was nodular lymphangitis, and the treatment of choice was itraconazole. Conventional diagnosis was made in all cases. Culture of clinical samples was more sensitive than direct examination because it allowed the isolation of Sporothrix spp. in all 54 cases. Molecular identification was performed in 22 cases, with Sporothrix schenkii sensu stricto being the most frequently isolated species.

Conclusions

This study allowed to know the epidemiology of this mycosis in Argentina, as well as the availability of diagnostic methods and the treatment of choice.

Preemptive Therapy in Cryptococcosis Adjusted for Outcomes

Cryptococcosis is one of the most serious opportunistic diseases in patients living with HIV. For this reason, early diagnosis and appropriate treatment are important.

OBJECTIVES

The aim of the study was to understand the development of patients diagnosed with cryptococcosis by detection of Cryptococcus antigen in serum by lateral flow assay (CrAg LFA) without nervous system involvement and with treatment in accordance with the results.

MATERIALS AND METHODS

A retrospective, longitudinal, analytical study was performed. Seventy patients with cryptococcosis initially diagnosed by serum CrAg LFA without meningeal involvement between January 2019 and April 2022 were analyzed for medical records. The treatment regimen was adapted to the results of blood culture, respiratory material, and pulmonary tomography imaging.

RESULTS

Seventy patients were included, 13 had probable pulmonary cryptococcosis, 4 had proven pulmonary cryptococcosis, 3 had fungemia, and 50 had preemptive therapy without microbiological or imaging findings compatible with cryptococcosis. Among the 50 patients with preemptive therapy, none had meningeal involvement or cryptococcosis recurrences to date.

CONCLUSION

Preemptive therapy avoided progression to meningitis in CrAg LFA-positive patients. Preemptive therapy with dose adjustment of fluconazole in patients with the mentioned characteristics was useful despite the use of lower doses than recommended.

[Invasive aspergillosis: definitions, diagnosis, and treatment]

Invasive aspergillosis (IA) is a serious disease with high mortality. There are several risk factors and in-hospital outbreaks related with construction have been described. An entity related to COVID-19 infection, known as COVID-19 associated pulmonary aspergillosis (CAPA), has recently appeared. Early and appropriate treatment is of paramount importance, especially in immunocompromised and critically ill patients. Diagnosis is based on recognition of predisposing factors, clinical signs, imaging, direct examination, culture, histopathology, and biomarkers such as galactomannan. The drug of choice is voriconazole, but alternative therapies must be taken into account given the increasing presence of resistant isolates.

Evaluation of an enzyme immunoassay technique on detecting urinary Histoplasma capsulatum antigen in the diagnosis of disseminated histoplasmosis in Argentina

INTRODUCTION

Histoplasmosis is a systemic mycosis of universal distribution, highly endemic in the Americas. It is caused by a dimorphic fungus Histoplasma capsulatum var. capsulatum. It affects both immunocompetent and immunocompromised individuals where progressive and disseminated forms are observed. A very important risk factor is HIV infection/AIDS, with a mortality rate of 20-40% in Latin America. The diagnosis of this mycosis is made by conventional and molecular methods or by antigen and antibody detection.

METHODS

In this retrospective, longitudinal and analytical study, carried out over a period of 2 years, the sensitivity (S) and specificity (E) of a commercial kit for the detection of Histoplasma antigen by EIA technique (HC-Ag) was evaluated in 50 patients with AIDSassociated histoplasmosis. In addition, its performance was compared with that of other diagnostic techniques routinely used in our laboratory.

RESULTS

HC-Ag had a S of 94%, E 96%, positive likelihood coefficient (CVP): 20.68 and negative likelihood coefficient (CVN): 0.06. The delay time of the results was 4 days, similar to that of antibody detection and n-PCR and much less than that of blood cultures. The combination of methods improved S to 100%; with similar values in E.

CONCLUSION

The HC-Ag method demonstrated its usefulness in the diagnosis of progressive disseminated histoplasmosis and the combination of methods is a good option to increase sensitivity and decrease the time to reach the diagnosis of certainty. This allows improving the strategy in the management of the disease and decreasing its case-fatality rate.

[Clinical problems in Medical Mycology: problem number 55]

A 31-year-old woman, with signs of HIV infection (oral thrush, weight loss, asthenia) presented to our hospital with dyspnea and fever. A rapid HIV test yielded a positive result, and cryptococcal capsular antigen was detected in serum. In the mycological study of the clinical respiratory samples, yeasts compatible with Cryptococcus were observed under light microscope in a wet mount; structures compatible with Pneumocystis jirovecii were also observed in Giemsa stain. Treatment for both pathologies was prescribed but, unfortunately, the patient died 7 days after. The finding of two etiologic agents in the same clinical picture is rare but not exceptional, and it always must be considered in immunocompromised hosts.

Genomic diversity of the human pathogen Paracoccidioides across the South American continent

Paracoccidioidomycosis (PCM) is a life-threatening systemic mycosis widely reported in the Gran Chaco ecosystem. The disease is caused by different species from the genus Paracoccidioides, which are all endemic to South and Central America. Here, we sequenced and analyzed 31 isolates of Paracoccidioides across South America, with particular focus on isolates from Argentina and Paraguay. The de novo sequenced isolates were compared with publicly available genomes. Phylogenetics and population genomics revealed that PCM in Argentina and Paraguay is caused by three distinct Paracoccidioides genotypes, P. brasiliensis (S1a and S1b) and P. restrepiensis (PS3). P. brasiliensis S1a isolates from Argentina are frequently associated with chronic forms of the disease. Our results suggest the existence of extensive molecular polymorphism among Paracoccidioides species, and provide a framework to begin to dissect the connection between genotypic differences in the pathogen and the clinical outcomes of the disease.

Clinical and microbiological characteristics of paracoccidioidomycosis in patients with AIDS in Buenos Aires, Argentina

Paracoccidioidomycosis (Pm) is a systemic disease, endemic in the American continent. There are two different clinical forms, the infant-juvenile or subacute form (PmS) and the chronic adult form (PmC). The human immunodeficiency virus (HIV) associated paracoccidioidomycosis (PmHIV) shares characteristics with both of the previously mentioned forms. The objective of this work was to describe the epidemiological, clinical and laboratory features of the PmHIV and to compare them with the ones of PmS and the PmC. A retrospective analysis of 119 patients with paracoccidioidomycosis was performed. Ninety four suffered the chronic form, 11 the subacute one and 14 were coinfected with HIV. Patients with PmHIV presented a CD4+ T lymphocytes median of 70.5 cells/μl, 71.4% had fever, 64.3% had a miliary pattern on the chest radiography, 64.3% had hepatosplenomegaly, 64.3% had mucosal lesions and 50% had skin lesions. One patient died during his hospitalization. The clinical presentation of Pm in patients with HIV resembled the subacute form with fever, hepatomegaly and skin lesions. However, they also tended to present mucosal lesions, positive serology for Pm and pulmonary parenchyma lesions as usually seen in PmC (9/14 PmHIV patients had overlapping features, while 4/14 PmHIV patients clinically resembled PmS and 1/14 PmC). The incidence of Pm has not changed with the burden of AIDS as it has happened with other fungal infections but it appears clinically different from the classic clinical forms of the disease.

[Histoplasmosis in AIDS patients without tegumentary manifestations]

BACKGROUND

Histoplasmosis is a mycosis with a high prevalence in HIV/AIDS patients. Clinical presentation includes a wide spectrum of manifestations and diagnosis usually takes up to several weeks in patients who do not present cutaneous lesions.

AIM

To determine the clinical and microbiological characteristics as well as some biochemical parameters in patients with AIDS-associated histoplasmosis without tegumentary lesions, in order to develop a guideline which enables an early empiric treatment in cases of difficult diagnosis.

METHODS

Medical records of 86 patients with histoplasmosis were reviewed; 31 patients with diagnosis of AIDS-associated histoplasmosis without cutaneous lesions were analyzed.

RESULTS

Fever was the most frequent symptom (96.7%), lung involvement was observed in 22 patients (70.9%), the most commonly radiological pattern was miliary pattern [(12/22), 54.5%]. Nineteen patients presented with splenomegaly. Blood culture sensitivity was 93.3% (28/30) and serology was positive only in 23.5% of the cases. Eight patients died (25.8%). Patients in which CD4+ T cell lymphocytes count was < 50 cells/μl, albumin levels < 2.5 g/dl and who presented with pancytopenia had an unfavorable outcome.

CONCLUSIONS

In HIV seropositive patients with fever associated to splenomegaly and bilateral miliar pattern in chest radiography, the empiric treatment with amphotericin B must be considered if signs and symptoms of unfavorable outcome are present and due to the time that it takes to arrive at an accurate diagnosis. In order to confirm the diagnosis, all microbiological samples should be collected prior to initiating therapy.

Antifungal Resistance in Clinical Isolates of Aspergillus spp.: When Local Epidemiology Breaks the Norm

Aspergillosis is a set of very frequent and widely distributed opportunistic diseases. Azoles are the first choice for most clinical forms. However, the distribution of azole-resistant strains is not well known around the world, especially in developing countries. The aim of our study was to determine the proportion of non-wild type strains among the clinical isolates of Aspergillus spp. To this end, the minimum inhibitory concentration of three azoles and amphotericin B (used occasionally in severe forms) was studied by broth microdilution. Unexpectedly, it was found that 8.1% of the isolates studied have a diminished susceptibility to itraconazole. This value turned out to be similar to the highest azole resistance rate reported in different countries across the world.

[Clinical problems in medical mycology: Problem number 51]

A 48 year-old immunocompetent woman, who had a nodular lesion in the neck and a dense infiltrate at the lower lobe of the left lung, presented at the Mycology Unit of Muñiz Hospital of Buenos Aires City. The pulmonary infiltrate disappeared spontaneously 3 months later. The histopathological study of the nodular lesion showed capsulated yeasts (mucicarmin and alcian blue positive stains) compatible with Cryptococcus. The mycological study of a new sample, obtained by a nodular puncture, allowed the isolation of yeasts, identified as Cryptococcus gattii (VGII). Latex test for Cryptococcus capsular antigen in serum was positive (1/100). CSF cultures rendered negative results. Fluconazole at a daily dose of 800mg was given during 45 days with partial improvement; as cultures from a new clinical sample were positive for Cryptococcus, the antimycotic was changed to itraconazole 400mg/day for 5 months, with an excellent clinical response.

Cryptococcosis in an Infectious Diseases Hospital of Buenos Aires, Argentina. Revision of 2041 cases: Diagnosis, clinical features and therapeutics

BACKGROUND

Cryptococcosis is still a life-threatening mycosis that continues to be of serious concern in Latin American countries, especially among HIV+positive population. However, there is not any reliable information about the prevalence of this disease in this region.

AIMS

The aim of this study is to report data of 2041 patients with cryptococcosis that were attended at the Infectious Diseases Hospital F. J. Muñiz over a 30 year-period.

METHODS

Information about demographic and clinical data, survival time and the applied treatment, was taken from the Mycology Unit database. Mycological exams from different clinical samples were performed. Cryptococcal capsular antigen in serum and cerebrospinal fluid was detected through the latex agglutination technique. Cryptococcus isolates were phenotypically identified and the genotype was determined in some of them. Susceptibility tests were carried out following M27-A3 document.

RESULTS

Seventy five percent of HIV+positive patients and 50% of the HIV-negative population were males. Mean ages were 34.1 in HIV+positive patients and 44.8 in the HIV-negative. Cryptococcosis was associated with AIDS in 98% of the cases. Meningeal compromise was seen in 90% of the patients. Although cerebrospinal fluid rendered more positive results, blood culture was the first diagnostic finding in some cases. Cryptococcal antigen showed positive results in 96.2% of the sera samples and in the 93.1% of the cerebrospinal fluid samples. Most of the isolates were Cryptococcus neoformans and belonged to genotype VNI. Minimal inhibitory concentration values were mostly below the epidemiological cutoff values.

CONCLUSIONS

We observed that thanks to a high level of clinical suspicion, early diagnosis, combined therapy and intracranial pressure control by daily lumbar punctures, the global mortality rate has markedly decreased through the years in the analyzed period.

[Efficacy of the treatment and secondary antifungal prophylaxis in AIDS-related histoplasmosis. Experience at the Francisco J. Muñiz Infectious Diseases Hospital in Buenos Aires]

BACKGROUND

Classic histoplasmosis is a systemic endemic mycosis due to Histoplasma capsulatum var. capsulatum. A significant reduction in the morbidity and mortality of AIDS-related histoplasmosis has been observed since the introduction of highly active antiretroviral therapy (HAART) and secondary antifungal prophylaxis.

AIMS

The aim of this study was to determine the current state of prognosis and treatment response of HIV-positive patients with histoplasmosis in the Francisco J. Muñiz Infectious Diseases Hospital in Buenos Aires City.

METHODS

A retrospective study was conducted using the demographic, clinical, immunological and treatment data of 80 patients suffering from AIDS-related histoplasmosis.

RESULTS

Of the 80 cases studied 65 were male, the median age was 36 years, with 73.7% of the patients being drug addicts, 82.5% of the patients was not receiving HAART at diagnosis, and 58.7% of the cases had less than 50 CD4+ cells/μl at the beginning of the treatment. The initial phase of treatment consisted of intravenous amphotericin B and/or oral itraconazole for 3 months, with 78.7% of the cases showing a good clinical response. Only 26/63 patients who were discharged from hospital continued with the follow-up of the HAART, secondary prophylaxis with itraconazole or amphotericin B. Secondary prophylaxis was stopped after more than one year of HAART if the patients were asymptomatic, had two CD₄+ cell counts greater than 150cells/μl, and undetectable viral loads. No relapses were observed during a two-year follow up after prophylaxis was stopped.

CONCLUSIONS

The treatment of histoplasmosis in HIV-positive patients was effective in 78.8% of the cases. The combination of HAART and secondary antifungal prophylaxis is safe, well tolerated, and effective. The low adherence of patients to HAART and the lack of laboratory kits for rapid histoplasmosis diagnosis should be addressed in the future. The usefulness of primary antifungal prophylaxis for cryptococcosis and histoplasmosis HIV-positive patients should be studied.

[Performance evaluation of Rapid™ Yeast Plus (Remel) system from two different culture media]

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.

[Clinical problems in medical mycology: Problem number 50]

We present the case of a 34 year-old man, HIV-positive, who had suffered a disseminated histoplasmosis treated with amphotericin B one year before his admission. He was admitted at the Infectious Diseases Muñiz Hospital with a non-lithiasic chlolecystitis. During the clinical examination perigenital skin lesions compatible with tinea cruris, as well as proximal subungual onychomycoses of toenails, were observed. Microsporum gypseum was isolated from both types of lesions. Oral terbinafine led to a good clinical response. Treatment prescription was a big challenge in this patient because he was receiving HAART and itraconazole, and there was scarce experience in the treatment of nail infections due to M. gypseum.

[Yeast urinary tract infections. Multicentre study in 14 hospitals belonging to the Buenos Aires City Mycology Network]

BACKGROUND

Urinary tract infections are a frequent ailment in patients in intensive care units. Candida and other yeasts cause 5-12% of these infections. The value of the finding of any yeast is controversial, and there is no consensus about which parameters are adequate for differentiating urinary infections from colonization or contamination.

AIMS

To analyse the epidemiological characteristics of patients with funguria, to determine potential cut-off points in cultures (to distinguish an infection from other conditions), to identify the prevalent yeast species, and to determine the value of a second urine sample.

METHODS

A multicentre study was conducted in intensive care units of 14 hospitals in the Buenos Aires City Mycology Network. The first and second samples of urine from every patient were cultured. The presence of white cells and yeasts in direct examination, colony counts, and the identification of the isolated species, were evaluated.

RESULTS

Yeasts grew in 12.2% of the samples. There was no statistical correlation between the number of white cells and the fungal colony-forming units. Eighty five percent of the patients had indwelling catheters. Funguria was not prevalent in women or in patients over the age of 65. Candida albicans, followed by Candida tropicalis, were the most frequently isolated yeasts. Candida parapsilosis and Candida glabrata appeared less frequently. The same species were isolated in 70% of second samples, and in 23% of the cases the second culture was negative.

CONCLUSIONS

It was not possible to determine a useful cut-off point for colony counts to help in the diagnosis of urinary infections. As in other publications, C. albicans, followed by C. tropicalis, were the most prevalent species.

[Disseminated histoplasmosis in patients with AIDS. Buenos Aires, 2009-2014]

A retrospective study was carried out on 171 cases of disseminated histoplasmosis diagnosed in HIV/AIDS patients during the period 2009-2014. Although HIV diagnosis rates remained stable over the study period, a sensible increase in the number of histoplasmosis cases was observed in the last three years. Disseminated histoplasmosis was prevalent in males with an average age of 37.8 years. At diagnosis, only 54/171 (31.6%) were receiving HAART, and CD4+ T-lymphocyte counts ranged from 4 to 264 cells/upsilon. Cutaneous lesions, including ulcerated papules or molluscoid plaques, were present in 110/171 (64.3%), with Histoplasma capsulatum being observed in all skin scraping specimens upon Giemsa staining. Respiratory manifestations were second in frequency with bronchoalveolar lavage showing a high diagnostic performance. Radiological findings included milliary patterns, interstitial infiltrates, and focalized condensations. Out of 141 blood cultures performed, H. capsulatum was isolated in 82 (58.2%). No significant difference in diagnostic performance was found between blood cultures and skin scraping (p = 0.6164). Other opportunistic infections were observed in 70/171 (40.9%) prior to or concomitantly with histoplasmosis. Association with Mycobacterium tuberculosis was recorded in 16/171 (9.4%) and one had a multi-drug resistant isolate. The severity of histoplasmosis determined the monotherapy with amphotericin B deoxycholate in 115 (67.3%), itraconazole in 42 (24.5%), and combined therapies in 14 (8.2%). Mortality was 19.9% (34/171). Finally, we emphasize that the higher prevalence in the last three years of the study should prompt the medical community to consider the diagnosis of histoplasmosis to reduce mortality of AIDS patients.

Relevance of intracranial hypertension control in the management of Cryptococcus neoformans meningitis related to AIDS

PURPOSE

To evaluate the relationship between intracranial hyperpressure (HICP) and mortality in patients with cryptococcal meningitis related to AIDS (CMRA).

METHODS

This was an observational retrospective study. Patients were treated according to the Infectious Diseases Society of America recommendations during the evaluation period (days 0, 3, 5 and after hospitalization). High intracranial pressure (HICP) was defined as ICP values of C250 mm H20. The correlation between HICP and mortality at each of the three time points considered was investigated. Statistical analysis on the descriptive parameters and on the probability of a "death" event (odds ratio, OR) at each of those three time points was performed using the statistical software program Epidata.

RESULTS

Eighty patients were included in this study, of whom 53 (66.25 %) were male. The average age of the patients was 37.5 ± 8.1 (range 22–55) years. The median CD4?lymphocyte cell count was 35 (range 0–367) cells/ml. Among the entire patient cohort, 53 patients had a favorable outcome, and the mortality rate was 33.75 %. At baseline (day 0), 57 subjects (71.5 %) presented HICP, and these patients had a higher mortality rate than those with a normal ICP, but the difference did not reach statistical significance[OR 1.65, 95 % confidence interval (CI) 0.56–4.84]. On day 3, 41 of the patients presented HICP, and HICP at this timepoint was significantly associated with an increased risk of mortality (OR 4.35, 95 % CI 1.56–12.09). On day 5, 35(43.5 %) patients presented HICP, and HCIP at this time point was also significantly associated with higher mortality (OR 7.23, 95 % CI 2.53–20.14).

CONCLUSION

The results of this study confirm an association between HICP and mortality in patients with CMRA and indicate that the control of ICP during the first 5 days of hospitalization is more important than managing HICP only at baseline.

[Evaluation of the VITEK 2 system (AST-YSO1 cards) for antifungal susceptibility testing against different Candida species]

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.

[Cryptococcal meningitis in patients with diabetes and AIDS]

INTRODUCTION

Cryptococcal meningitis is a severe AIDS-related infectious disease, with a high mortality rate. Diabetes mellitus (DM) is a metabolic disorder very common worldwide. Infectious diseases in diabetic patients are always more severe than in non-diabetic ones. The aim of this study was to compare the outcome of a group of HIV-positive patients with DM and cryptococcal meningitis with a similar group HIV-positive patients with cryptococcal meningitis, but without DM.

MATERIAL AND METHODS

A total of 182 clinical records of HIV-positive patients suffering cryptococcal meningitis were reviewed, and 28 of them with similar clinical and epidemiological characteristics, were chosen. They included 14 patients with DM (group A) and the remaining 14 who did not suffer this metabolic disorder (group B).

RESULTS

Only 21.4% (3/14 cases) of group A patients had negative CSF cultures after 10 weeks of treatment. In group B patients, 78.5% (11/14 cases) achieved negative CSF cultures before 10 weeks. A higher overall mortality rate was observed in the diabetic patients (85.7%, 12/14 cases) than in the non-diabetic group (21.4%, 3/14 cases). All CSF isolates were identified as Cryptococcus neoformans, and all strains were susceptible in vitro to amphotericin B and fluconazole.

CONCLUSIONS

Cryptococcal meningitis in diabetic patients was associated with a poor clinical outcome and a high mortality rate. A longer treatment induction period is suggested in order to improve the outcome of cryptococcal meningitis in diabetic patients.

[Clinical problems in medical mycology: Problem number 47]

A 66 year-old man, who had lived in Paraguay and was a rural worker, was admitted to Infectious Diseases Hospital F. J. Muñiz in Buenos Aires. He presented fever, loss of body weight, cough, mucopurulent expectoration, wide perianal ulceration, paresthesia and paresis of both legs as well as vesical and anal sphincter dysfunction. He was a heavy smoker and drinker. Thorax X-ray examination showed bilateral micronodular interstitial lesions. With a NMR of the dorsolumbar spine region a nodular lesion outside the spinal cord (which produced compression of this organ) was shown. The diagnosis of disseminated paracoccidiodomycosis was based on the finding of Paracoccidioides brasiliensis in the skin ulcer in histopathology and mycology studies, and on the positive results of serologic tests with paracoccidioidin antigen. The patient was treated with trimethoprim-sulfamethoxazole with good clinical outcome.

[Clinical problems in medical mycology: problem number 45]

A 43 year-old diabetic woman, who suffered chronic cough and brown expectoration, is presented in this clinical problem. X-ray exam and CT thorax scan showed a cavitary lung lesion, located at the upper field of the left lung. This lesion had 5 cm in diameter, with a thick wall and a spherical shadow inside. The diagnosis of chronic cavitary pulmonary coccidioidomycosis was based on the isolation of Coccidioides sp. from cultures of expectoration and bronchoalveolar lavage, and the detection of specific antibodies in immunodiffusion test and counterimmunoelectrophoresis with coccidiodin. Her diabetes was not well controlled. She was treated with intravenous amphotericin B and oral itraconazole, with good clinical response; after four months of treatment the patient abandoned clinical controls. We suppose that the patient presented a coccidioidal fungus ball, inside a chronic cavitary lesion due to pulmonary coccidiodomycosis. She came from an endemic zone of coccidioidomycosis in the Northwest of the Argentine Republic (Catamarca Province).

Kinetics of HIV-1 in cerebrospinal fluid and plasma in cryptococcal meningitis

In order to determine HIV-1 kinetics in cerebrospinal fluid (CSF) and plasma in patients with cryptococcal meningitis (CM), we undertook a prospective collection of paired CSF/plasma samples from antiretroviral therapy-free HIV-infected patients with CM. Samples were obtained at baseline (S1) and at the second (S2) and third (S3) weeks of antifungal therapy. HIV-1 CSF concentrations were significantly lower in both S2 and S3 with respect to S1. Plasma concentrations remained stable. HIV-1 concentrations were higher in plasma than CSF in all cases. Patients who survived the episode of CM (but not those who died) showed a decrease in CSF viral load, what suggests different viral kinetics of HIV-1 in the CSF according to the clinical course of this opportunistic disease.

Standardization and characterization of antigens for the diagnosis of aspergillosis

The aim of this study was to develop and characterize antigens for the diagnosis of aspergillosis. Nine strains of Aspergillus species Aspergillus fumigatus , Aspergillus flavus , and Aspergillus niger were grown in Sabouraud and Smith broth to produce exoantigens. The antigens were tested by immunodiffusion against sera from patients with aspergillosis and other systemic mycoses. The protein fraction of the antigens was detected by SDS–PAGE; Western blot and representative bands were assessed by mass spectrometry coupled to a nano Acquity UltraPerformance LC and analyzed by the Mascot search engine. Concurrently, all sera were tested with Platelia Aspergillus EIA. The most reactive antigens to sera from patients infected by A. fumigatus were produced by A. fumigatus MG2 Sabouraud and pooled A. fumigatus Sabouraud samples, both with a sensitivity of 93% and specificity of 100% and 97%, respectively. Aspergillus niger and A. flavus antigens were reactive against A. niger and A. flavus sera, each one with a sensitivity and specificity of 100%. Two proteins, probably responsible for antigenic activity, β-glucosidase in A. fumigatus and α-amylase in A. niger were attained. The commercial kit had a specificity of 22%, sensitivity of 100%, positive predictive value of 48%, and negative predictive value of 100%. The antigens produced showed high sensitivity and specificity and can be exploited for diagnostics of aspergilloma.

[Disseminated infection due to Penicillium marneffei related to HIV infection: first observation in Argentina]

The first case observed in Argentina of AIDS-related human penicillosis is herein presented. The patient was a six- teen year-old young man coming from a rural area of southern China. He was admitted at the F. J. Muñiz Hospital of Buenos Aires city with severe pneumonia and adult respiratory distress. Penicillium marneffei was isolated from bronchoalveolar lavage fuid and was microscopically observed in a skin cytodiagnosis. P. marneffei identification was confirmed by rRNA amplification and its phenotypic characteristics. The patient suffered an advanced HIV infection and also presented several AIDS-related diseases due to CMV, nosocomial bacterial infections and Pneumocystis jirovecii which led to a fatal outcome.

[Onychomycosis: multicentre epidemiological, clinical and mycological study]

BACKGROUND

Onychomycosis accounts for up to 50% of all nail disorders. They can be caused by: yeasts, dermatophytes and non-dermatophyte moulds.

OBJECTIVES AND METHODS

A multicentre study designed to determine the prevalence, mycological test results, aetiological agents, and clinical presentation of onychomycosis was carried out. All fingernail and toenail samples taken during a one year period at 9 diagnostic centres were included.

RESULTS

A total of 5,961 samples were analysed, of which 82.3% were from toenails and 17.7% from fingernails. The mean age of the patients was 49.7 years, and 66% were females. Direct microscopic examination was positive in 61% of the samples. In adults, 61.2% of toenails were positive using potassium hydroxide (KOH), and 43.7% were positive in cultures. The prevailing aetiological agents belong to the dermatophyte group (82.8%), and distal subungual was the most common clinical form. In fingernails, direct examination showed 59.8% positive samples, and cultures were positive in 52.9%. The prevailing agents were yeasts belonging to Candida species, and onycholysis was the most common lesion.

CONCLUSIONS

Direct mycological examinations were positive in 61%, a higher value than that found in other series. Dermatophytes were prevalent in toenails of both sexes, and in finger nails yeast were prevalent in females, and dermatophytes in males. Non-dermatophyte moulds corresponded to 4.8% of toenail and 2.05% of fingernails isolates.

[Presumptive identification of Candida spp. and other clinically important yeasts: usefulness of 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.

Variables that influence HIV-1 cerebrospinal fluid viral load in cryptococcal meningitis: a linear regression analysis

Background

The central nervous system is considered a sanctuary site for HIV-1 replication. Variables associated with HIV cerebrospinal fluid (CSF) viral load in the context of opportunistic CNS infections are poorly understood. Our objective was to evaluate the relation between: (1) CSF HIV-1 viral load and CSF cytological and biochemical characteristics (leukocyte count, protein concentration, cryptococcal antigen titer); (2) CSF HIV-1 viral load and HIV-1 plasma viral load; and (3) CSF leukocyte count and the peripheral blood CD4+ T lymphocyte count.

Methods

Our approach was to use a prospective collection and analysis of pre-treatment, paired CSF and plasma samples from antiretroviral-naive HIV-positive patients with cryptococcal meningitis and assisted at the Francisco J Muñiz Hospital, Buenos Aires, Argentina (period: 2004 to 2006). We measured HIV CSF and plasma levels by polymerase chain reaction using the Cobas Amplicor HIV-1 Monitor Test version 1.5 (Roche). Data were processed with Statistix 7.0 software (linear regression analysis).

Results

Samples from 34 patients were analyzed. CSF leukocyte count showed statistically significant correlation with CSF HIV-1 viral load (r = 0.4, 95% CI = 0.13-0.63, p = 0.01). No correlation was found with the plasma viral load, CSF protein concentration and cryptococcal antigen titer. A positive correlation was found between peripheral blood CD4+ T lymphocyte count and the CSF leukocyte count (r = 0.44, 95% CI = 0.125-0.674, p = 0.0123).

Conclusion

Our study suggests that CSF leukocyte count influences CSF HIV-1 viral load in patients with meningitis caused by Cryptococcus neoformans.

[Isolation of Candida dubliniensis in different clinical samples. Analysis of phenotypical methods to differentiate it from Candida albicans]

In order to estimate the frequence of Candida dubliniensis in clinical samples in F. J. Muñiz Infectious Diseases Hospital, a total of 388 yeasts from September 2005 to August 2007. There were 212 isolates which presented a green color on CHROMagar Candida medium and produced germ tubes and chlamidoconidiae in milk-agar; so as to distinguish whether they corresponded to Candida albicans or C. dubliniensis, different phenotypical methods were utilized. It was also evaluated the usefulness of each one in order to suggest a simple, economic and reliable identification algorithm. Each isolate was subcultured in two chromogenic media and then, the following determinations were done: chlamidospores production in Staib-agar, tomato-carrot-agar and tobacco-agar, colonies macromorphology was also studied in the last medium; opacity-test in Tween 80-CaCl2 agar (lipase activity), growing capacity at 45 degrees C, and D-xylose assimilation. Thirteen strains (6.1%) corresponded to C. dubliniensis. The difference in color between both species on chromogenic media was not so stressed as it is pointed out in some works. The more specific and sensitive tests were the ability to grow at 45 degrees C, D-xylose assimilation, color and macroscopic appearance in tobacco-agar. Between 11.6% and 15.1% of C. albicans strains produced chlamidoconidiae in the 3 differential media tested. The opacity halo (lipase) was evident in 95.6% of C. albicans isolates but 2 out of 13 C. dubliniensis also presented precipitation halo. We consider that at least 3 different phenotypical methods should be used to distinguish properly these two species since none of the tests is absolutely sensitive or specific.