[Value of direct and indirect diagnostic methods in systemic mycoses associated with AIDS]

Meningeal cryptococcosis and SARS-CoV-2 infection in people living with HIV/AIDS

INTRODUCTION

Fungal infections in patients with COVID-19 was one of the most debated topics during the pandemic.

OBJECTIVES

To analyze the clinical characteristics and evolution of people living with HIV/AIDS and coinfection with cryptococcus and COVID-19 (group A) or without it (group B).

MATERIALS AND METHODS

This is an analytical and retrospective study. We reviewed medical records of patients with meningeal cryptococcosis between April 2020 and May 2021.

RESULTS

We studied 65 people living with HIV/AIDS and with cryptococcosis infection diagnosed from April 2020 to May 2021. Fifteen patients with HIV/AIDS suffered from cryptococcosis and COVID-19, and out of these, 14 presented meningitis (group A), while 28 suffered from meningeal cryptococcosis, but did not have COVID-19 (group B).

CONCLUSIONS

No statistically significant differences were observed between the two groups (A and B) considering: intracranial hypertension, presence of Cryptococcus antigens in cerebrospinal fluid, sensorium deterioration or mortality. The detection of Cryptococcus antigens in serum by lateral flow assay was highly effective to rapidly diagnose cryptococcosis in patients with HIV/AIDS who also developed COVID-19. Patients of both groups consulted for cryptoccocosis sometime after, in comparison with the pre-pandemic cases related to this infection.

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.

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.

Diagnosis of Progressive Disseminated Histoplasmosis in Advanced HIV: A Meta-Analysis of Assay Analytical Performance

Histoplasmosis is an important cause of mortality in people with advanced HIV, especially in countries with limited access to diagnostic assays. Histoplasmosis can be diagnosed using culture, histopathology, and antibody, antigen, and molecular assays. Several factors may affect the analytical performance of these laboratory assays, including sample type, clinical stage of the disease, and previous use of antifungal treatment, among others. Here we describe the results of a systematic literature review, followed by a meta-analysis of the analytical performances of the diagnostic laboratory assays employed. Our initial search identified 1631 references, of which 1559 references were excluded after title and abstract screening, leaving 72 references identified as studies relevant to the validation of histoplasmosis diagnostic assays. After evaluating the full text, 30 studies were selected for final review, including one paper not identified in the initial search. The meta-analysis for assay analytical performance shows the following results for the overall sensitivity (Sen) and specificity (Spe) of the various methods evaluated: Culture, Sen 77% (no data for specificity calculation); antibody detection assays, Sen 58%/Spe 100%; antigen detection assays, Sen 95%/Spe 97%; and DNA detection assays (molecular), Sen 95%/Spe 99%. Of the 30 studies reviewed, nearly half (n = 13) evaluated Histoplasma antigen assays, which were determined to be the most accurate methodology for diagnosis of progressive disseminated histoplasmosis in advanced HIV (inverse of the negative likelihood ratio was 13.2). Molecular assays appear promising for accurate diagnosis of histoplasmosis, but consensus on exact techniques is needed. Cultures showed variable sensitivity related to sample type and laboratory handling. Finally, antibody assays presented high specificity but low sensitivity. This poor sensitivity is most likely due the highly immunosuppressed state of this patient population. Diagnostic assays are crucial for accurate diagnosis of progressive disseminated histoplasmosis (PDH) with advanced HIV disease.

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.

[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.

Correlation of Etest and Neo-Sensitabs diffusion assays on Mueller-Hinton-methylene blue agar with broth microdilution reference method (CLSI-M27-A2) for testing susceptibilities of Cryptococcus neoformans to amphotericin B and fluconazole

Cryptococcus neoformans causes disseminated infection in 7-8% of HIV positive patients admitted to Hospital F. J. Muñiz in Buenos Aires. Meningoencephalitis is the most frequent clinical manifestation and is one of the main causes of death in those patients with AIDS. The standard treatment for this mycosis consists of amphotericin B followed by fluconazole until two successive cultures of CFS are negative. Although resistance to these drugs is infrequent, minimal inhibitory concentrations (MIC) of some antifungals can be high. Since it is important to know the susceptibility levels of this fungus to the antifungal drugs usually employed in our institution, we analyzed the susceptibility test results of C. neoformans with two diffusion methods (Etest and NeoSensitabs tablets) employing Mueller-Hinton agar with 2% glucose and 0.5 microg/ml methylene blue. These results were compared with MICs obtained through the use of the broth microdilution reference method (CLSI). Results showed good agreement with the reference method, with no very major errors and only two major errors for fluconazole using NeoSensitabs tablets. For all the above mentioned, we confirm the usefulness of Mueller-Hinton agar to evaluate C. neoformans susceptibility to amphotericin B and fluconazole with these two agar diffusion methods.

DIAGNOSIS OF HISTOPLASMOSIS

Endemic mycoses can be challenging to diagnose and accurate interpretation of laboratory data is important to ensure the most appropriate treatment for the patients. Although the definitive diagnosis of histoplasmosis (HP), one of the most frequent endemic mycoses in the world, is achieved by direct diagnosis performed by micro and/or macroscopic observation of Histoplasma capsulatum (H. capsulatum), serologic evidence of this fungal infection is important since the isolation of the etiologic agents is time-consuming and insensitive. A variety of immunoassays have been used to detect specific antibodies to H. capsulatum. The most applied technique for antibody detection is immunodiffusion with sensitivity between 70 to 100 % and specificity of 100%, depending on the clinical form. The complement fixation (CF) test, a methodology extensively used on the past, is less specific (60 to 90%). Detecting fungal antigens by immunoassays is valuable in immunocompromised individuals where such assays achieve positive predictive values of 96-98%. Most current tests in diagnostic laboratories still utilize unpurified antigenic complexes from either whole fungal cells or their culture filtrates. Emphasis has shifted, however, to clinical immunoassays using highly purified and well-characterized antigens including recombinant antigens. In this paper, we review the current conventional diagnostic tools, such as complement fixation and immunodiffusion, outline the development of novel diagnostic reagents and methods, and discuss their relative merits and disadvantages to the immunodiagnostic of this mycosis.

Cryptococcosis associated with AIDS in the Muñiz Hospital of Buenos Aires

Some epidemiologic, diagnostic and immunologic aspects of 93 (75 males and 18 women) cases of cryptococcosis (CRY) associated with AIDS, hospitalized in the Muñiz Hospital (MH) in Buenos Aires during 1994, were retrospectively studied. The median age (MA) of the patients under study was 28 years (17-49 y); 30 (17-49) y for males and 23 (22-34) y for women. Intravenous drug addiction (34% of patients) and homo/bisexuality in men (17%) were the most frequent risk factors for HIV infection. The MA of these groups were 27.5 (17-41) y and 34 (25-41) y, respectively. Microscopic CSF examination with India ink and the blood cultures (lysis-centrifugation) achieved the diagnosis of CRY in 67 (72%) and 16 (17%) patients, respectively. At diagnosis, the median titers for Cryptococcus neoformans capsular antigen were 1/1,000, 1/100 and 1/1 in serum, CSF and urine, respectively. Sixty five strains of C. neoformans were insolated from clinical samples; all were identified at variety neoformans employing the culture medium proposed by Salkin & Hurd and the D-proline assimilation test. At diagnosis, CD4+ lymphocytes counts were < 50/microliter in 46 patients (83.63%), and were between 51 and 200/microliter in 9 (16.4%). The CD4+/CD8+ ratio was < 1 in all patients. Most patients were born (83%) and lived at diagnosis (96%) in Buenos Aires (Bs As) city, Bs As outskirts towns and cities located in Bs As province.

Histoplasmosis in the Muñiz Hospital of Buenos Aires

Some epidemiological and immunological characteristics and the methodology of diagnosis of 44 cases of histoplasmosis (HP); 36 (27 males and 9 women) associated with AIDS (HP+AIDS) and 8 (7 males and 1 female) with other predisposing factors (HP+non AIDS), diagnosed in the Muñiz Hospital (MH) during 1994, were retrospectively studied. The median age (MA) of HP+AIDS patients was 28 years; 25.5 (22-40) in the women and 28.5 (20-42) in the men and 50 (22-58) years in the HP+non AIDS patients. The more frequent risk factors for HIV infection were intravenous drug addiction (55%) and homo/bisexuality (19%). The MA of these groups were 28 (20-39) and 41 (26-42) years, respectively. Tobaccoism was a predisposing factor in 83% of HP+non AIDS patients. The muco-cutaneous lesions scraping and blood-cultures established the initial diagnosis in 53% and 36% of HP+AIDS patients, respectively and the muco-cutaneous lesions biopsies in 75% of HP+non AIDS cases. At time of diagnosis, all HP+AIDS patients had < 200 while HP+non AIDS patients had > 200 CD4 + lymphocytes/microliters. Seventy two per cent of HP+AIDS patients were born in Buenos Aires (Bs As) city and 62% of HP+non AIDS patients were born in provinces of Argentina other than Bs As. At moment of diagnosis, 87.5% of HP+AIDS and 62.5% of HP+non AIDS patients lived in Bs As city and Bs As outskirts.

Blood culture as a parameter of treatment effectiveness in experimental histoplasmosis of the hamster

The aim of this study was to determine the value of blood culture as a parameter of treatment effectiveness in experimental histoplasmosis. A total of thirty five hamsters, weighing approximately 120g, were inoculated intracardially with 0.1 ml of a suspension containing 4 x 10(7) cells/ml of the yeast phase of H. capsulatum. Treatments were started one week after the infection and lasted for 3 weeks. The azoles, (itraconazole, saperconazole and fluconazole) were administered once a day by gavage, at a dose of 8 mg/kg; Amphotericin B was given intraperitoneally every other day at a dose of 6mg/kg. Blood samples (1 ml) were obtained by heart punction from the 4th day after infection and were seeded in Sabouraud honey-agar and BHI-agar. The hamsters that survived were killed one week after treatment completion and the following criteria were considered for treatment evaluation: 1) rate of spontaneous death, at the end of the experience; 2) microscopic examination of Giemsa smears from liver and spleen and 3) determination of CFU in spleen cultures. Amphotericin B was the most effective drug, with negative blood cultures at day 20, negative spleen cultures in all cases and all the animals survived until the end of the study. Fluconazole was the less effective drug, blood cultures were positive during the whole experience, spleen cultures showed a similar average of CFU when compared with the control animals and 42.8% of these animals died. Saperconazole and itraconazole showed a similar activity, with survival of all hamsters and negative blood cultures at 23 and 26 days respectively. Blood culture seems to be valuable parameter for treatments' evaluation in experimental histoplasmosis of the hamster.