Capítulo 3: criptococose pulmonar

Macrophages-derived exo-miR-4449 induced by Cryptococcus affects HUVEC permeability and promotes pyroptosis in BEAS-2B via the HIC1 pathway

Macrophages have recently been discovered to assume a significant role in the progression of cryptococcosis. However, the potential involvement of macrophage-derived exosomes in the pathogenesis of cryptococcosis remains uncertain. In this study, we investigated the changes of microRNAs in macrophage exosomes (exo-miRNAs) in cryptococcal infections and the role of markedly altered exo-miRNAs in the modulation of Human Umbilical Vein Endothelial Cells (HUVEC) permeability and ROS accumulation and pyroptosis in Human Bronchial Epithelioid Cells (BEAS-2B). Techniques such as microarray analysis and real-time quantitative PCR were used to detect different exo-miRNAs and to screen for the most highly expressed exo-miRNAs. Then its mimics were transfected into HUVEC to study its effect on the monolayer permeability of HUVEC. Finally, the relationship between this exo-miRNAs and the ROS accumulation and pyroptosis was verified by bioinformatics analysis. The results showed that five exo-miRNAs were overexpressed and two exo-miRNAs were reduced, among which, exo-miR-4449 was expressed at the highest level. Exo-miR-4449 could be internalized by HUVEC and enhanced its monolayer permeability. Moreover, exo-miR-4449 was found to promote ROS accumulation and pyroptosis in BEAS-2B through HIC1 pathway. Thus, exo-miR-4449 plays an important role in the pathogenesis of cryptococcosis and holds promise as a significant biomarker for treatment.

Comparative analysis of diagnostic methods for the detection of Cryptococcus neoformans meningitis

BACKGROUND

Cryptococcosis is a devastating opportunistic infection in immunocompromised individuals, primarily in people living with HIV/AIDS. This study evaluated a protocol for the early diagnosis of meningitis due to C. neoformans, utilizing established molecular techniques from serum and CSF samples.

METHODS

The 18S and 5.8S (rDNA-ITS) sequence-specific nested PCR assays were compared with direct India ink staining and the latex agglutination test for detection of C. neoformans in serum and cerebrospinal fluid (CSF) from 49 Brazilian suspected meningitis patients. Results were validated with samples obtained from 10 patients negative for cryptococcosis and HIV, and by analysis of standard C. neoformans strains.

PRINCIPAL FINDINGS

The 5.8S DNA-ITS PCR was more sensitive (89-100%) and specific (100%) than the 18S rDNA PCR and conventional tests (India ink staining and latex agglutination) for identification of C. neoformans. While the 18S PCR exhibited a sensitivity (72%) similar to that of the latex agglutination assay in serum samples, it was superior to the latex agglutination assay when testing CSF, with a sensitivity of 84%. However, the latex agglutination was superior to the 18SrDNA PCR in specificity in CSF (92%). The 5.8S DNA-ITS PCR yielded the highest levels of accuracy (96-100%) of any test for detection (serological and mycological) of C. neoformans in both serum and CSF.

CONCLUSION

Use of the nested 5.8S PCR was superior to other techniques for the diagnosis of cryptococcosis. The possibility of using serum, a non-invasively collected material, in a targeted 5.8S PCR analysis to identify Cryptococcus spp. is recommended, especially in immunosuppressed patients. Our results indicate that nested 5.8S PCR can increase the diagnostic capability of cryptococcosis, and we suggest its use to monitor patients in the future.

The Spectrum of Infections in Patients with Lung Cancer

Although diagnostic and therapeutic advances in lung cancer (LC) have increased the survival of patients, infection and its complications are still among the most important causes of mortality. The disruption of tissue caused by tumor mass, management of cancer therapy and alteration in the humoral/cellular immune systems due to both cancer itself and therapy considerably increase susceptibility to infection in cancer patients. Particularly, opportunistic microorganisms should be considered, then applying rapid and sensitive diagnostic methods for them. Thus, cancer patients who are already exposed to difficult, long-term and expensive treatments can be prevented from dying from complications related to infections.

Cryptococcal antigen among HIV1-infected individuals in north-central Nigeria

Background and Purpose

The potential for the invasion of the central nervous system by Cryptococcus species is underscored by the presence of this organism in the blood of immunocompromised individuals. Early adoption of sensitive methods for the diagnosis of Cryptococcus species will reduce the high morbidity and mortality associated with this disease. Regarding this, the aim of the present research was to detect cryptococcal antigen among HIV1- infected individuals in north-central Nigeria.

Materials and Methods

This prospective cross-sectional study was carried out on HIV-1 infected individuals accessing care at three health facilities in north-central Nigeria between November 2014 and March 2017. For the purpose of the study, blood samples were collected from 300 HIV1-infected individuals within the age group of 3-65 years. The CD4+ T-cell count was determined, and the samples were analyzed for cryptococcal antigenemia using the methods of lateral flow assay (LFA) and culture technique.

Results

Cryptococcus antigen was detected in 19.67% (59/300) of the patients, and only 25.4% (15/59) of the LFA-positive samples showed Cryptococcus species growth on Sabouraud dextrose agar after 3 days. Furthermore, fungal growth was observed in one of the specimens, which was LFA negative. Additionally, 30 of the 59 LFA-positive patients had cryptococcal antigen in their serum with a CD4+ T-cell count of < 150 cells/mm³.

Conclusion

As the findings of the present study indicated, infection with Cryptococcus species is a problem among HIV-infected patients in the region under study. Therefore, all HIV patients, especially those with a CD4+ T-cell count of < 150 cells/mm³, referring to the HAART clinics in Nigeria, should be screened for cryptococcal antigen.

Clinical significance of the isolation of Candida species from hospitalized patients

In this study, we isolated and phenotypically identified 108 yeast strains from various clinical specimens collected from 100 hospitalized patients at three tertiary hospitals in São Luís-Maranhão, Brazil, from July to December 2010. The isolates were analyzed for their susceptibility to four of the most widely used antifungal agents in the surveyed hospitals, amphotericin B, fluconazole, 5-flucytosine and voriconazole. The species identified were Candida albicans (41.4%), Candida tropicalis (30.1%), C. glabrata (7.4%), Candida parapsilosis (5.5%), Candida krusei (4.6%), Cryptococcus neoformans (4.6%), Trichosporon spp . (3.7%), Candida norvegensis (0.9%), Rhodotorula glutinis (0.9%) and Pichia farinosa (0.9%). A higher isolation rate was observed in the following clinical specimens: urine (54 isolates; 50%), respiratory tract samples (21 isolates; 19.4%) and blood (20 isolates; 18.6%). Candida albicans isolates were 100% sensitive to all antifungal agents tested, whereas Candida krusei and Crytococcus neoformans displayed intermediate resistance to 5-flucytosine, with Minimal Inhibitory Concentration (MIC) values of 8 mg/mL and 16 mg/mL, respectively. Both strains were also S-DD to fluconazole with an MIC of 16 mg/mL. C. tropicalis was resistant to 5-flucytosine with an MIC of 32 μg/mL. This study demonstrates the importance of identifying the yeast species involved in community and nosocomial infections.

Pulmonary cryptococcosis in non-AIDS patients

OBJECTIVE

To investigate the clinical features, management, and prognosis of pulmonary cryptococcosis in non-acquired immunodeficiency syndrome (AIDS) patients.

METHOD

24 cases of pulmonary cryptococcosis with accurate pathological diagnosis were retrospectively studied.

RESULTS

15 male patients and nine female patients were diagnosed at the first affiliated hospital of Sun Yat-sen University from November 1999 to November 2011. The mean age at the time of diagnosis was 44.2±11.3 years (range: 24 to 65 years). Among these patients, 13 had other comorbidities. 15 were symptomatic and the other nine were asymptomatic. The most common presenting symptoms were cough, chest tightness, expectoration, and fever. None had concurrent cryptococcal meningitis. The most frequent radiologic abnormalities on chest computed tomography (CT) scans were solitary or multiple pulmonary nodules, and masses or consolidations, and most lesions were located in the lower lobes. All patients had biopsies for the accurate diagnosis. Among the 24 patients, nine patients underwent surgical resections (eight had pneumonectomy via thoracotomy and one had a pneumonectomy via thoracoscopy). Five of the patients who underwent surgery also received antifungal drug therapy (fluconazole) for one to three months after the surgery. The other 15 only received antifungal drug therapy (fluconazole or voriconazole) for three to six months (five patients are still on therapy). The follow-up observation of 19 patients who had already finished their treatments lasted from two to 11 years, and there was no relapse, dissemination, or death in any of these patients.

CONCLUSION

Non-AIDS patients with pulmonary cryptococcosis have a good prognosis with appropriate management.

Long-term surveillance and treatment of subclinical cryptococcosis and nasal colonization by Cryptococcus neoformans and C. gattii species complex in captive koalas (Phascolarctes cinereus)

Cryptococcosis is an important systemic mycosis caused by members of the Cryptococcus neoformans species complex. This disease is potentially fatal in various animals, including koalas. We describe the long-term surveillance and treatment of subclinical cryptococcosis and nasal colonization of koalas by Cryptococcus neoformans and C. gattii. Of the 15 animals investigated through the use of samples obtained by nasal swabs, antigen titer measurements, and pathologic examination, C. neoformans was found associated with nine koalas and C. gattii with one animal. Nine koalas showed subclinical disease and one clinical infections and antigenemia. Treatment with fluconazole, itraconazole and amphotericin B upon detection of C. neoformans or C. gattii was not effective. The results of the present study showed that C. neoformans was the predominant species isolated from the nasal swab samples and the fungus might have naturally become associated with the koalas' nasal cavities at Kanazawa Zoological Gardens. The unclear treatment effectiveness might have been caused by a shorter treatment period that is routinely used and unstable itraconazole absorption. This investigation also underscores the need for identifying effective treatment regimens for subclinical cryptococcosis and efficient measures for eradicating C. neoformans and C. gattii in koalas.

Concurrent Cryptococcal and Pneumocystis Pneumonia along with Pulmonary Tuberculosis in an HIV-Positive Patient: Lessons Learned for Early Management

Case: We are presenting a 50-year-old patient of pulmonary tuberculosis, on anti-tuberculosis therapy (ATT) for last 2 months who presented with fever, cough, breathlessness, anorexia, and weight loss. The case was found to be HIV reactive. His sputum sample showed Candida albicans and Pneumocystis jirovecii. Fluconazole and cotrimoxazole + sulphamethoxazole were added. The index case did not respond to the treatment and his clinical condition started to deteriorate and he developed headache, vomiting, and dysphagia. Repeat sputum sample and cerebrospinal fluid (CSF) showed Cryptococcus neoformans which was found to be sensitive to Amphotericin B. Amphotericin B was added to the treatment and patient clinically responded to treatment. In conclusion, emphasis should be given to correct etiological identification, allowing appropriate treatment and decreasing the morbidity and mortality in these patients as concomitant opportunistic infections may cause diagnostic problems.