Pulmonary Talaromycosis: A Window into the Immunopathogenesis of an Endemic Mycosis

Novel Insights into the Antimicrobial and Antibiofilm Activity of Pyrroloquinoline Quinone (PQQ); In Vitro, In Silico, and Shotgun Proteomic Studies

Microbial infections pose a significant global health threat, affecting millions of individuals and leading to substantial mortality rates. The increasing resistance of microorganisms to conventional treatments requires the development of novel antimicrobial agents. Pyrroloquinoline quinone (PQQ), a natural medicinal drug involved in various cellular processes, holds promise as a potential antimicrobial agent. In the present study, our aim was, for the first time, to explore the antimicrobial activity of PQQ against 29 pathogenic microbes, including 13 fungal strains, 8 Gram-positive bacteria, and 8 Gram-negative bacteria. Our findings revealed potent antifungal properties of PQQ, particularly against Syncephalastrum racemosum, Talaromyces marneffei, Candida lipolytica, and Trichophyton rubrum. The MIC values varied between fungal strains, and T. marneffei exhibited a lower MIC, indicating a greater susceptibility to PQQ. In addition, PQQ exhibited notable antibacterial activity against Gram-positive and -negative bacteria, with a prominent inhibition observed against Staphylococcus epidermidis, Proteus vulgaris, and MRSA strains. Remarkably, PQQ demonstrated considerable biofilm inhibition against the MRSA, S. epidermidis, and P. vulgaris strains. Transmission electron microscopy (TEM) studies revealed that PQQ caused structural damage and disrupted cell metabolism in bacterial cells, leading to aberrant morphology, compromised cell membrane integrity, and leakage of cytoplasmic contents. These findings were further affirmed by shotgun proteomic analysis, which revealed that PQQ targets several important cellular processes in bacteria, including membrane proteins, ATP metabolic processes, DNA repair processes, metal-binding proteins, and stress response. Finally, detailed molecular modeling investigations indicated that PQQ exhibits a substantial binding affinity score for key microbial targets, including the mannoprotein Mp1P, the transcriptional regulator TcaR, and the endonuclease PvuRTs1I. Taken together, our study underscores the effectiveness of PQQ as a broad-spectrum antimicrobial agent capable of combating pathogenic fungi and bacteria, while also inhibiting biofilm formation and targeting several critical biological processes, making it a promising therapeutic option for biofilm-related infections.

The microbial damage and host response framework: lesson learned from pathogenic survival trajectories and immunoinflammatory responses of Talaromyces marneffei infection

The adverse outcomes of fungal infection in mammalian hosts depend on the complex interactions between the host immune system and pathogen virulence-associated traits. The main clinical problems arise when the host response is either too weak to effectively eliminate the pathogen or overly aggressive, resulting in host tissue damage rather than protection. This article will highlight current knowledge regarding the virulence attributions and mechanisms involved in the dual-sided role of the host immune system in the immunopathogenesis of the thermally dimorphic fungus Talaromyces marneffei through the lens of the damage response framework (DRF) of microbial pathogenesis model.

Metagenomic Next-Generation Sequencing as an Effective Diagnostic Tool for Talaromycosis in HIV-Negative Patients

The diagnosis of Talaromyces marneffei infection in HIV-negative patients remains challenging. There is an urgent need for rapid and convenient methods to diagnose this complicated disease. The aim of this study was to evaluate the diagnostic efficiency of metagenomic next-generation sequencing (mNGS) for talaromycosis in non-HIV-infected patients by comparing mNGS with traditional microbial culture. In total, 66 samples from 57 patients were analyzed via both mNGS and microbial culture. The ROC curve showed a sensitivity for mNGS of 97.22%, which was greater than that of microbial culture (61.11%). Samples from the respiratory tract, infectious skin lesions, and lymph nodes are recommended as routine samples for talaromycosis detection via mNGS. Furthermore, mNGS significantly reduced the diagnostic time compared to microbial culture. Overall, our study demonstrated that mNGS is a promising tool for rapid and accurate pathogenic detection in HIV-negative patients with talaromycosis.

Lung infections due to emerging fungal pathogens

PURPOSE OF REVIEW

This review highlights the epidemiology, pathogenesis and clinical management of pulmonary infections caused by emerging fungal organisms.

RECENT FINDINGS

Emerging fungal infections have arisen as a result of population and environmental changes. An enlarging pool of immunocompromised hosts on triazole antifungal prophylaxis has led to an increased incidence of non- Aspergillus molds, such as Fusarium , Scedosporium and Lomentospora spp. Advances in diagnostic capabilities led to the identification of the Emergomyces genus and non- dermatitidis Blastomyces species, which have a significant disease burden in Africa and the Middle East. Climate change has contributed to changing the distribution of previously confined endemic mycoses, like coccidioidomycosis and talaromycosis. These emerging organisms pose important diagnostic and therapeutic challenges.

SUMMARY

Newly recognized pathogenic fungi and established endemic mycoses with expanding geographic boundaries have become important agents of pulmonary disease. There is a dearth of clinical evidence on the appropriate management of these infections.

Talaromycosis from Wuhan: two-case report and literature review

Background

Talaromycosis is a serious opportunistic infectious disease caused by Talaromyces marneffei, which mostly occurs in immunocompromised patients. The disease is mainly prevalent in tropical countries and regions of Southeast Asia and South Asia, but non-endemic areas also have patients with Talaromycosis. The disease has no characteristic clinical manifestations and is difficult to diagnose. Delayed diagnosis often leads to death.

Case presentation

Both patients had cellular immunodeficiency. Case 1 had a history of acquired immune deficiency syndrome, and case 2 had a history of renal transplantation and glucose-6-phosphate dehydrogenase deficiency. They all had fever, anemia, fatigue, and skin lesions. Case 1 had gastrointestinal bleeding, enlarged lymph nodes, and hepatosplenomegaly. Case 2 had cough and dyspnea. Both patients had thrombocytopenia and hypoalbuminemia; an increased neutrophil ratio, procalcitonin, and C-reactive protein; and abnormal liver function and coagulation dysfunction. Case 1 sputum culture, blood culture, and bronchoalveolar lavage fluid were positive for T. marneffei. T. marneffei was detected in the blood culture of case 2, with infection of Candida parapsilosis and Pneumocystis jirovecii. Chest computed tomography scan mainly showed pulmonary exudative lesions. Although these two patients were actively treated, they died of poor efficacy.

Conclusion

Talaromycosis has an insidious onset, long course, atypical clinical symptoms, imaging performance and laboratory results, difficult diagnosis, and high mortality. Therefore, it is important to promptly consider and treat Talaromycosis in immunocompromised patients upon infection in order to reduce mortality.

Talaromyces marneffei endocarditis initially detected by Next Generation Sequencing: A case report

BACKGROUND

Talaromyces marneffei (T. marneffei) is a thermal dimorphic fungus, which can cause lung or blood stream infection in patients, often life-threatening. However, endocarditis caused by T. marneffei has not been reported. For elderly patients with implanted cardiac devices or artificial valves, the prevention and treatment of infective endocarditis should not be ignored.

METHODS

This is a descriptive study of a T. marneffei endocarditis by joint detection of cardiac ultrasound examination, peripheral blood DNA metagenomics Next Generation Sequencing (mNGS), and in vitro culture.

RESULTS

We describe an 80-year-old female patient with an unusual infection of T. marneffei endocarditis. After intravenous drip of 0.2 g voriconazole twice a day for antifungal treatment, the patient showed no signs of improvement and their family refused further treatment.

CONCLUSION

Infective endocarditis is becoming more and more common in the elderly due to the widely use of invasive surgical procedures and implantation of intracardiac devices. The diagnosis and treatment of T. marneffei endocarditis is challenging because of its rarity. Here, we discussed a case of T. marneffei endocarditis, and emphasized the role of mNGS in early diagnosis, which is of great significance for treatment and survival rate of patients.

Microbiomes Detected by Bronchoalveolar Lavage Fluid Metagenomic Next-Generation Sequencing among HIV-Infected and Uninfected Patients with Pulmonary Infection

Comparison of lung microbiomes between HIV-infected and uninfected patients with pulmonary infection by metagenomic next-generation sequencing (mNGS) has not been described in China. The lung microbiomes detected in bronchoalveolar fluid (BALF) by mNGS among HIV-infected and uninfected patients with pulmonary infection were reviewed in the First Hospital of Changsha between January 2019 and June 2022. In total, 476 HIV-infected and 280 uninfected patients with pulmonary infection were enrolled. Compared with HIV-uninfected patients, the proportions of Mycobacterium (P = 0.011), fungi (P < 0.001), and viruses (P < 0.001) were significantly higher in HIV-infected patients. The higher positive rate of Mycobacterium tuberculosis (MTB; P = 0.018), higher positive rates of Pneumocystis jirovecii and Talaromyces marneffei (all P < 0.001), and higher positive rate of cytomegalovirus (P < 0.001) contributed to the increased proportions of Mycobacterium, fungi, and viruses among HIV-infected patients, respectively. The constituent ratios of Streptococcus pneumoniae (P = 0.007) and Tropheryma whipplei (P = 0.002) in the bacteria spectrum were significantly higher, while the constituent ratio of Klebsiella pneumoniae (P = 0.005) was significantly lower in HIV-infected patients than in HIV-uninfected patients. Compared with HIV-uninfected patients, the constituent ratios of P. jirovecii and T. marneffei (all P < 0.001) in the fungal spectrum were significantly higher, while the constituent ratios of Candida and Aspergillus (all P < 0.001) were significantly lower in HIV-infected patients. In comparison to HIV-infected patients without antiretroviral therapy (ART), the proportions of T. whipplei (P = 0.001), MTB (P = 0.024), P. jirovecii (P < 0.001), T. marneffei (P < 0.001), and cytomegalovirus (P = 0.008) were significantly lower in HIV-infected patients on ART. Significant differences in lung microbiomes exist between HIV-infected and uninfected patients with pulmonary infection, and ART influences the lung microbiomes among HIV-infected patients with pulmonary infection. IMPORTANCE A better understanding of lung microorganisms is conducive to early diagnosis and treatment and will improve the prognosis of HIV-infected patients with pulmonary infection. Currently, few studies have systematically described the spectrum of pulmonary infection among HIV-infected patients. This study is the first to provide comprehensive information on the lung microbiomes of HIV-infected patients with pulmonary infection (as assessed by more sensitive metagenomic next-generation sequencing of bronchoalveolar fluid) compared with those from HIV-uninfected patients, which could provide a reference for the etiology of pulmonary infection among HIV-infected patients.

Impact of pathogen genetics on clinical phenotypes in a population of Talaromyces marneffei from Vietnam

Talaromycosis, a severe and invasive fungal infection caused by Talaromyces marneffei, is difficult to treat and impacts those living in endemic regions of Southeast Asia, India, and China. While 30% of infections result in mortality, our understanding of the genetic basis of pathogenesis for this fungus is limited. To address this, we apply population genomics and genome-wide association study approaches to a cohort of 336 T. marneffei isolates collected from patients who enrolled in the Itraconazole vs Amphotericin B for Talaromycosis trial in Vietnam. We find that isolates from northern and southern Vietnam form two distinct geographical clades, with isolates from southern Vietnam associated with increased disease severity. Leveraging longitudinal isolates, we identify multiple instances of disease relapse linked to unrelated strains, highlighting the potential for multistrain infections. In more frequent cases of persistent talaromycosis caused by the same strain, we identify variants arising over the course of patient infections that impact genes predicted to function in the regulation of gene expression and secondary metabolite production. By combining genetic variant data with patient metadata for all 336 isolates, we identify pathogen variants significantly associated with multiple clinical phenotypes. In addition, we identify genes and genomic regions under selection across both clades, highlighting loci undergoing rapid evolution, potentially in response to external pressures. With this combination of approaches, we identify links between pathogen genetics and patient outcomes and identify genomic regions that are altered during T. marneffei infection, providing an initial view of how pathogen genetics affects disease outcomes.

Rare cases of Talaromyces pneumonia in individuals with underlying cancer and no travel to endemic areas

Introduction

Talaromyces marneffei causes a systemic fungal infection, referred to as talaromycosis, in immunocompromised individuals. Talaromycosis is an AIDS (acquired immunodeficiency syndrome) defining illness for patients living in the Southeast Asian region. Here we present two rarely reported cases of pulmonary talaromycosis in Southern California in patients with active cancer, negative HIV status, and no prior travel history to endemic regions.

Case description

Case 1: A 76-year-old male with a past medical history of emphysema and latent tuberculosis status post rifampin treatment, presented with a necrotic lung mass. He was diagnosed with squamous cell lung carcinoma and bronchoalveolar lavage cultures grew Talaromyces marneffei. He had no animal exposure or prior travel history to Asia. Due to a transfusion reaction to liposomal amphotericin (the mainstay of treatment), he required a transition to posaconazole. He was HIV-negative and expired due to underlying cancer and infection complications.Case2: A 63-year-old male with a past medical history of tuberculosis, diabetes, and cavitary pneumonia with bronchoscopy positive for Talaromyces presented with worsening back pain and was found to have multiple sites of poorly differentiated adenocarcinoma likely originating from gastric adenocarcinoma. He was HIV-negative and expired due to complications from underlying cancer and infection.

Conclusion

We demonstrate that patients with pulmonary Talaromyces are becoming more prominent outside of endemic areas even in the setting of no prior travel. In addition, since patients with this infection are severely immunosuppressed, they require extensive workup for other comorbidities such as possible underlying cancer or tuberculosis.

Impact of pathogen genetics on clinical phenotypes in a population of Talaromyces marneffei from Vietnam

Talaromycosis, a severe and invasive fungal infection caused by Talaromyces marneffei , is difficult to treat and impacts those living in endemic regions of southeast Asia, India, and China. While 30% of infections result in mortality, our understanding of the genetic basis of pathogenesis for this fungus is limited. To address this, we apply population genomics and genome wide association study approaches to a cohort of 336 T. marneffei isolates collected from patients who enrolled in the Itraconazole versus Amphotericin B for Talaromycosis (IVAP) trial in Vietnam. We find that isolates from northern and southern Vietnam form two distinct geographical clades, with isolates from southern Vietnam associated with increased disease severity. Leveraging longitudinal isolates, we identify multiple instances of disease relapse linked to unrelated strains, highlighting the potential for multi-strain infections. In more frequent cases of persistent talaromycosis caused by the same strain, we identify variants arising over the course of patient infections that impact genes predicted to function in the regulation of gene expression and secondary metabolite production. By combining genetic variant data with patient metadata for all 336 isolates, we identify pathogen variants significantly associated with multiple clinical phenotypes. In addition, we identify genes and genomic regions under selection across both clades, highlighting loci undergoing rapid evolution, potentially in response to external pressures. With this combination of approaches, we identify links between pathogen genetics and patient outcomes and identify genomic regions that are altered during T. marneffei infection, providing an initial view of how pathogen genetics affects disease outcomes.

Talaromyces marneffei infection and complicate manifestation of respiratory system in HIV-negative children

BACKGROUND

Respiratory symptoms are the earliest clinical manifestation of Talaromyces marneffei (TM) infection. In this study, we aimed to improve the early identification of TM infection in human immunodeficiency virus (HIV)-negative children with respiratory symptoms as the first manifestation, analyze the risk factors, and provide evidence for diagnosis and treatment.

METHODS

We retrospectively analyzed six cases of HIV-negative children with respiratory system infection symptoms as the first presentation.

RESULTS

All subjects (100%) had cough and hepatosplenomegaly, and five subjects (83.3%) had a fever; other symptoms and signs included lymph node enlargement, rash, rales, wheezing, hoarseness, hemoptysis, anemia, and thrush. Additionally, 66.7% of the cases had underlying diseases (three had malnutrition, one had severe combined immune deficiency [SCID]). The most common coinfecting pathogen was Pneumocystis jirovecii, which occurred in two cases (33.3%), followed by one case of Aspergillus sp. (16.6%). Furthermore, the value of β-D-glucan detection (G test) increased in 50% of the cases, while the proportion of NK decreased in six cases (100%). Five children (83.3%) were confirmed to have the pathogenic genetic mutations. Three children (50%) were treated with amphotericin B, voriconazole, and itraconazole, respectively; three children (50%) were treated with voriconazole and itraconazole. All children were tested for itraconazole and voriconazole plasma concentrations throughout antifungal therapy. Two cases (33.3%) relapsed after drug withdrawal within 1 year, and the average duration of antifungal treatment for all children was 17.7 months.

CONCLUSION

The first manifestation of TM infection in children is respiratory symptoms, which are nonspecific and easily misdiagnosed. When the effectiveness of anti-infection treatment is poor for recurrent respiratory tract infections, we must consider the condition with an opportunistic pathogen and attempt to identify the pathogen using various samples and detection methods to confirm the diagnosis. It is recommended the course for anti-TM disease be longer than one year for children with immune deficiency. Monitoring the blood concentration of antifungal drugs is important.

Clinical Manifestations of Human Exposure to Fungi

Biological particles, along with inorganic gaseous and particulate pollutants, constitute an ever-present component of the atmosphere and surfaces. Among these particles are fungal species colonizing almost all ecosystems, including the human body. Although inoffensive to most people, fungi can be responsible for several health problems, such as allergic fungal diseases and fungal infections. Worldwide fungal disease incidence is increasing, with new emerging fungal diseases appearing yearly. Reasons for this increase are the expansion of life expectancy, the number of immunocompromised patients (immunosuppressive treatments for transplantation, autoimmune diseases, and immunodeficiency diseases), the number of uncontrolled underlying conditions (e.g., diabetes mellitus), and the misusage of medication (e.g., corticosteroids and broad-spectrum antibiotics). Managing fungal diseases is challenging; only four classes of antifungal drugs are available, resistance to these drugs is increasing, and no vaccines have been approved. The present work reviews the implications of fungal particles in human health from allergic diseases (i.e., allergic bronchopulmonary aspergillosis, severe asthma with fungal sensitization, thunderstorm asthma, allergic fungal rhinosinusitis, and occupational lung diseases) to infections (i.e., superficial, subcutaneous, and systemic infections). Topics such as the etiological agent, risk factors, clinical manifestations, diagnosis, and treatment will be revised to improve the knowledge of this growing health concern.

Idiopathic non-cirrhotic portal hypertension in a patient with Talaromyces marneffei infection: a case report

BACKGROUND

The etiopathogenesis of idiopathic non-cirrhotic portal hypertension (INCPH) is so far poorly understood. Altered immunity, blood diseases, infections, congenital defects and drug exposure have been documented in a part of patients with INCPH owing to increased recognition of the disorder in patients with HIV, or various haematological disorders or autoimmune diseases. We aim to discuss the possible etiopathogenesis of INCPH.

CASE PRESENTATION

We reported that a patient with intestinal infection of T. Marneffei and hyper-IgE syndrome, a group of rare primary immunodeficiency disorders, was finally diagnosed with INCPH for gastroesophageal variceal bleeding. The diagnosis was mainly based on histopathological features. Transjugular intrahepatic portosystemic shunt was performed and there was no recurrence of melena during the six-month follow-up.

CONCLUSION

In the context of immunodeficiency, INCPH may associated with intestinal infections. Thus, screening for enterogenic infection and immunological disorders in patients with unexplained portal hypertension is necessary.

Unusual Talaromyces marneffei and Pneumocystis jirovecii coinfection in a child with a STAT1 mutation: A case report and literature review

Talaromyces marneffei and Pneumocystis jirovecii are the common opportunistic pathogens in immunodeficient patients. There have been no reports of T. marneffei and P. jirovecii coinfection in immunodeficient children. Signal transducer and activator of transcription 1 (STAT1) is a key transcription factor in immune responses. STAT1 mutations are predominately associated with chronic mucocutaneous candidiasis and invasive mycosis. We report a 1-year-2-month-old boy diagnosed with severe laryngitis and pneumonia caused by T. marneffei and P. jirovecii coinfection, which was confirmed by smear, culture, polymerase chain reaction and metagenome next-generation sequencing of bronchoalveolar lavage fluid. He has a known STAT1 mutation at amino acid 274 in the coiled-coil domain of STAT1 according to whole exome sequencing. Based on the pathogen results, itraconazole and trimethoprim-sulfamethoxazole were administered. This patient's condition improved, and he was discharged after two weeks of targeted therapy. In the one-year follow-up, the boy remained symptom-free without recurrence.

Loss to follow-up associated factors in patients with chronic pulmonary aspergillosis and its impact on the disease prognosis

Objective

Pulmonary aspergillosis is a rare but challenging pulmonary disease. The conditions of patients with chronic pulmonary aspergillosis (CPA) can be even more complicated. The mortality rate of CPA remains high, and the prognostic factors are not well established due to a high proportion of loss to follow-up. In this study, we aim to explore factors associated with loss to follow-up in CPA patients and their impact on the disease prognosis after withdrawing anti-fungal treatments.

Methods

Patients with confirmed CPA, who were admitted to the Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Guangzhou Medical University from March 2017 to November 2019, were enrolled in this prospective study. The enrolled patients were followed up for 6 months after discharge. For loss to follow-up patients, the reasons for loss to follow-up and their prognosis after withdrawing anti-fungal treatments during loss to follow-up were recorded by telephone communication. Multivariate logistic regression analysis was performed to determine factors associated with loss to follow-up.

Results

The 199 out of 298 screened patients were included in the study. Except for 67 cases with regular follow-up, the rest 132 cases were lost to follow-up. Factors, including age > 60 years (OR = 2.036, P = 0.03), monthly income ≤ $583 (OR = 5.568, P = 0.0001), education ≤ 6 years (OR = 7.474, P = 0.0001), and non-local residence (OR = 5.893, P = 0.0001) were associated with the loss to follow-up according to multivariate logistic regression analysis. The most common reasons for loss to follow-up were economic factors and clinic visit distance. The overall case fatality rate (CFR) within 180 days in patients with regular follow-up and patients who stopped anti-fungal treatment during the loss to follow-up was 0% and 19.65%, respectively.

Conclusion

The proportion of loss to follow-up in CPA patients remained high. Age (>60 years), poor financial status, low education, and non-local residence were the key factors associated with the loss to follow-up in this study. Our study reveals the need to optimize the follow-up procedures and improve the patients understanding about the benefits and limitations of follow-up to reduce the CFR.

Respiratory system Talaromyces marneffei infection in HIV-negative children.. [DOI: 10.21203/rs.3.rs-2294600/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background Respiratory symptoms are the earliest clinical manifestation of Talaromyces marneffei (TM) infection. In this study, we aimed to improve the early identification of TM infection in human immunodeficiency virus (HIV)-negative children with respiratory symptoms as the first manifestation, analyze the risk factors, and provide evidence for diagnosis and treatment. Methods We retrospectively analyzed six cases of HIV-negative children with respiratory system infection symptoms as the first presentation. Results All subjects (100%) had cough and hepatosplenomegaly, and five subjects (83.3%) had a fever; other symptoms included lymph node enlargement, rash, rales, wheezing, hoarseness, hemoptysis, anemia, and thrush. Additionally, 66.7% of the cases had underlying diseases (three had malnutrition, one had severe combined immune deficiency [SCID]). The most common coinfecting pathogen was Pneumocystis carinii, which occurred in two cases (33.3%), followed by one case of Aspergillus (16.6%). Furthermore, the value of β-D-glucan detection (G experimental) increased in 50% of the cases, while the proportion of NK decreased in six cases (100%). Five children (83.3%) were confirmed to have the pathogenic genetic mutations. Three children (50%) were treated with amphotericin B, voriconazole, and itraconazole, respectively; three children (50%) were treated with voriconazole and itraconazole. All children were tested for itraconazole and voriconazole plasma concentrations throughout antifungal therapy. Two cases (33.3%) relapsed after drug withdrawal within 1 year, and the average duration of antifungal treatment for all children was 17.7 months. Conclusion The first manifestation of TM infection in children is respiratory symptoms, which are nonspecific and easily misdiagnosed. When the effectiveness of anti-infection treatment is poor for recurrent respiratory tract infections, we must consider the condition with an opportunistic pathogen and attempt to identify the pathogen using various samples and detection

Neglected mycobiome in HIV infection: Alterations, common fungal diseases and antifungal immunity

Human immunodeficiency virus (HIV) infection might have effects on both the human bacteriome and mycobiome. Although many studies have focused on alteration of the bacteriome in HIV infection, only a handful of studies have also characterized the composition of the mycobiome in HIV-infected individuals. Studies have shown that compromised immunity in HIV infection might contribute to the development of opportunistic fungal infections. Despite effective antiretroviral therapy (ART), opportunistic fungal infections continue to be a major cause of HIV-related mortality. Human immune responses are known to play a critical role in controlling fungal infections. However, the effect of HIV infection on innate and adaptive antifungal immunity remains unclear. Here, we review recent advances in understanding of the fungal microbiota composition and common fungal diseases in the setting of HIV. Moreover, we discuss innate and adaptive antifungal immunity in HIV infection.

Chest Imaging in Systemic Endemic Mycoses

Endemic fungal infections are responsible for high rates of morbidity and mortality in certain regions of the world. The diagnosis and management remain a challenge, and the reason could be explained by the lack of disease awareness, variability of symptoms, and insidious and often overlooked clinical presentation. Imaging findings are nonspecific and frequently misinterpreted as other more common infectious or malignant diseases. Patient demographics and clinical and travel history are important clues that may lead to a proper diagnosis. The purpose of this paper is to review the presentation and differential diagnosis of endemic mycoses based on the most common chest imaging findings.

Clinical performance of metagenomic next-generation sequencing for the rapid diagnosis of talaromycosis in HIV-infected patients

Background

Talaromycosis is an invasive endemic mycosis caused by the dimorphic fungus Talaromyces marneffei (T. marneffei, TM). It mainly affects immunodeficient patients, especially HIV-infected individuals, which causes significant morbidity and mortality. Culture-based diagnosis takes a long turnaround time with low sensitivity, leading to treatment delay. In this study, we aimed to evaluate the performance of Metagenomic Next-Generation Sequencing (mNGS) for the rapid diagnosis of talaromycosis in HIV-infected patients.

Methods

Retrospectively analysis was conducted in HIV-infected cases at Changsha First Hospital (China) from January 2021 to March 2022. Patients who underwent routine microbiological examination and mNGS testing in parallel were enrolled. The clinical final diagnosis was used as a reference standard, and cases were classified into the TM group (60 cases) and the non-TM group (148 cases). The clinical performances of mNGS were compared with culture and serum Galactomannan (GM). The mixed infections detected by mNGS were analyzed. The impact of mNGS detection on treatment was also investigated.

Results

The sensitivity of mNGS test reached 98.3% (95% CI, 89.8-99.9), which was significantly higher than culture (66.7% [95% CI, 53.2-77.9], P < 0.001) and serum GM (83.3% [95% CI, 71.0-91.2], P < 0.05). The specificity of 98.6% (95% CI, 94.7-99.7) was similar to culture (100.0% [95% CI, 96.8-100.0], P = 0.156), and superior to serum GM (91.9% [95% CI, 85.9-95.5], P < 0.05). In bronchoalveolar lavage fluid (BALF) samples, the positive rate of mNGS was 97.6%, which was significantly higher than culture (28.6%, P <0.001). mNGS has excellent performance in the identification of mixed infection in TM group patients. Cytomegalovirus, Epstein-Barr virus and Pneumocystis jirovecii were the most common concurrent pathogens. In summary, 60.0% (36/60) patients were added or adjusted to antimicrobial therapy after mNGS test.

Conclusion

mNGS is a powerful technique with high specificity and sensitivity for the rapid diagnosis of talaromycosis. mNGS of BALF samples may be a good option for early identification of T. marneffei in HIV-infected individuals with manifestations of infection. Moreover, mNGS shows excellent performance in mixed infection, which benefits timely treatment and potential mortality reduction.

Talaromyces marneffei Infection: Virulence, Intracellular Lifestyle and Host Defense Mechanisms

Talaromycosis (Penicilliosis) is an opportunistic mycosis caused by the thermally dimorphic fungus Talaromyces (Penicillium) marneffei. Similar to other major causes of systemic mycoses, the extent of disease and outcomes are the results of complex interactions between this opportunistic human pathogen and a host’s immune response. This review will highlight the current knowledge regarding the dynamic interaction between T. marneffei and mammalian hosts, particularly highlighting important aspects of virulence factors, intracellular lifestyle and the mechanisms of immune defense as well as the strategies of the pathogen for manipulating and evading host immune cells.