Lung Epithelial Cell Line Immune Responses to Pneumocystis

Pneumocystis sp. are fungal pathogens and members of the Ascomycota phylum. Immunocompetent individuals can readily eliminate the fungus, whereas immunocompromised individuals can develop Pneumocystis jirovecii pneumonia (PJP). Currently, over 500,000 cases occur worldwide, and the organism is listed on the recently released WHO fungal priority pathogens list. Overall, the number of PJP cases over the last few decades in developed countries with the use of highly effective antiretroviral therapy has decreased, but the cases of non-HIV individuals using immunosuppressive therapies have significantly increased. Even with relatively effective current anti-Pneumocystis therapies, the mortality rate remains 30-60% in non-HIV patients and 10-20% during initial episodes of PJP in HIV/AIDS patients. Although the role of alveolar macrophages is well studied and established, there is also well-established and emerging evidence regarding the role of epithelial cells in the immune response to fungi. This mini review provides a brief overview summarizing the innate immune response of the lung epithelium and various continuously cultured mammalian cell lines to Pneumocystis.

Increased Hospitalizations Involving Fungal Infections during COVID-19 Pandemic, United States, January 2020-December 2021

Hospitalizations involving fungal infections increased 8.5% each year in the United States during 2019-2021. During 2020-2021, patients hospitalized with COVID-19-associated fungal infections had higher (48.5%) in-hospital mortality rates than those with non-COVID-19-associated fungal infections (12.3%). Improved fungal disease surveillance is needed, particularly during respiratory virus pandemics.

Gaining an Understanding of Pneumocystosis in Wales

Pneumocystis pneumonia (PcP) is a serious complication of many significant immunocompromising conditions. Prior incidence estimates in Wales are based on PcP's presentation in the HIV and transplant populations. The objectives were to describe the incidence of PcP in Wales using laboratory reporting measures and assess the impact of underlying immunosuppression cause on mortality. All positive PCR results for PcP between 2015 and 2018 were identified. The total number of unique positives with clinical and radiological correlation was 159 patients, a mean of 39.75 annually. The healthcare records of these patients were reviewed. The mortality at one month was 35.2% and 49.1% at one year. HIV remains the commonest cause of immunosuppression but has lower mortality than non-HIV conditions (12% vs. 59% at one year, p < 0.00001). Non-HIV conditions were categorised as life-threatening and non-life threatening but had a non-significant mortality (66% vs. 54%; p = 0.149), highlighting the negative impact of PcP. An incidence of PcP in Wales of 1.23-1.26 cases per 100,000 has been identified, 32-35% greater than the upper limit previously estimated. There is high mortality in non-HIV patients regardless of immunosuppression cause. A heightened awareness of PcP in these groups will hasten diagnosis and potentially improve mortality.

Novel Pneumocystis Antigens for Seroprevalence Studies

Pneumocystis jirovecii is the most common cause of fungal pneumonia in children under the age of 2 years. However, the inability to culture and propagate this organism has hampered the acquisition of a fungal genome as well as the development of recombinant antigens to conduct seroprevalence studies. In this study, we performed proteomics on Pneumocystis-infected mice and used the recent P. murina and P. jirovecii genomes to prioritize antigens for recombinant protein expression. We focused on a fungal glucanase due to its conservation among fungal species. We found evidence of maternal IgG to this antigen, followed by a nadir in pediatric samples between 1 and 3 months of age, followed by an increase in prevalence over time consistent with the known epidemiology of Pneumocystis exposure. Moreover, there was a strong concordance of anti-glucanase responses and IgG against another Pneumocystis antigen, PNEG_01454. Taken together, these antigens may be useful tools for Pneumocystis seroprevalence and seroconversion studies.

The Dual Benefit of Sulfasalazine on Pneumocystis Pneumonia-Related Immunopathogenesis and Antifungal Host Defense Does Not Require IL-4Rα-Dependent Macrophage Polarization

Pneumocystis is a respiratory fungal pathogen that is among the most frequent causes of life-threatening pneumonia (PcP) in immunocompromised hosts. Alveolar macrophages play an important role in host defense against Pneumocystis, and several studies have suggested that M2 polarized macrophages have anti-Pneumocystis effector activity. Our prior work found that the immunomodulatory drug sulfasalazine (SSZ) provides a dual benefit during PcP-related immune reconstitution inflammatory syndrome (IRIS) by concurrently suppressing immunopathogenesis while also accelerating macrophage-mediated fungal clearance. The benefits of SSZ were associated with heightened Th2 cytokine production and M2 macrophage polarization. Therefore, to determine whether SSZ improves the outcome of PcP through a mechanism that requires Th2-dependent M2 polarization, RAG2-/- mice lacking interleukin 4 receptor alpha chain (IL-4Rα) on macrophage lineage cells were generated. As expected, SSZ treatment dramatically reduced the severity of PcP-related immunopathogenesis and accelerated fungal clearance in immune-reconstituted RAG2-/- mice. Similarly, SSZ treatment was also highly effective in immune-reconstituted RAG2/IL-4Rα-/- and RAG2/gamma interferon receptor (IFN-γR)-/- mice, demonstrating that neither IL-4Rα-dependent M2 nor IFN-γR-dependent M1 macrophage polarization programs were required for the beneficial effects of SSZ. Despite the fact that macrophages from RAG2/IL-4Rα-/- mice could not respond to the Th2 cytokines IL-4 and IL-13, M2-biased alveolar macrophages were identified in the lungs following SSZ treatment. These data demonstrate that not only does SSZ enhance phagocytosis and fungal clearance in the absence of macrophage IL-4Rα signaling, but also that SSZ promotes M2 macrophage polarization in an IL-4Rα-independent manner. These findings could have implications for the treatment of PcP and other diseases in which M2 polarization is beneficial.

Pneumocystis Exacerbates Inflammation and Mucus Hypersecretion in a Murine, Elastase-Induced-COPD Model

Inflammation and mucus hypersecretion are frequent pathology features of chronic respiratory diseases such as asthma and COPD. Selected bacteria, viruses and fungi may synergize as co-factors in aggravating disease by activating pathways that are able to induce airway pathology. Pneumocystis infection induces inflammation and mucus hypersecretion in immune competent and compromised humans and animals. This fungus is a frequent colonizer in patients with COPD. Therefore, it becomes essential to identify whether it has a role in aggravating COPD severity. This work used an elastase-induced COPD model to evaluate the role of Pneumocystis in the exacerbation of pathology, including COPD-like lung lesions, inflammation and mucus hypersecretion. Animals infected with Pneumocystis developed increased histology features of COPD, inflammatory cuffs around airways and lung vasculature plus mucus hypersecretion. Pneumocystis induced a synergic increment in levels of inflammation markers (Cxcl2, IL6, IL8 and IL10) and mucins (Muc5ac/Muc5b). Levels of STAT6-dependent transcription factors Gata3, FoxA3 and Spdef were also synergically increased in Pneumocystis infected animals and elastase-induced COPD, while the levels of the mucous cell-hyperplasia transcription factor FoxA2 were decreased compared to the other groups. Results document that Pneumocystis is a co-factor for disease severity in this elastase-induced-COPD model and highlight the relevance of STAT6 pathway in Pneumocystis pathogenesis.

Analysis of Pneumocystis Transcription Factor Evolution and Implications for Biology and Lifestyle

Pneumocystis jirovecii kills hundreds of thousands of immunocompromised patients each year. Yet many aspects of the biology of this obligate pathogen remain obscure because it is not possible to culture the fungus in vitro independently of its host. Consequently, our understanding of Pneumocystis pathobiology is heavily reliant upon bioinformatic inferences. We have exploited a powerful combination of genomic and phylogenetic approaches to examine the evolution of transcription factors in Pneumocystis species. We selected protein families (Pfam families) that correspond to transcriptional regulators and used bioinformatic approaches to compare these families in the seven Pneumocystis species that have been sequenced to date with those from other yeasts, other human and plant pathogens, and other obligate parasites. Some Pfam families of transcription factors have undergone significant reduction during their evolution in the Pneumocystis genus, and other Pfam families have been lost or appear to be in the process of being lost. Meanwhile, other transcription factor families have been retained in Pneumocystis species, and some even appear to have undergone expansion. On this basis, Pneumocystis species seem to have retained transcriptional regulators that control chromosome maintenance, ribosomal gene regulation, RNA processing and modification, and respiration. Meanwhile, regulators that promote the assimilation of alternative carbon sources, amino acid, lipid, and sterol biosynthesis, and iron sensing and homeostasis appear to have been lost. Our analyses of transcription factor retention, loss, and gain provide important insights into the biology and lifestyle of Pneumocystis. IMPORTANCE Pneumocystis jirovecii is a major fungal pathogen of humans that infects healthy individuals, colonizing the lungs of infants. In immunocompromised and transplant patients, this fungus causes life-threatening pneumonia, and these Pneumocystis infections remain among the most common and serious infections in HIV/AIDS patients. Yet we remain remarkably ignorant about the biology and epidemiology of Pneumocystis due to the inability to culture this fungus in vitro. Our analyses of transcription factor retentions, losses, and gains in sequenced Pneumocystis species provide valuable new views of their specialized biology, suggesting the retention of many metabolic and stress regulators and the loss of others that are essential in free-living fungi. Given the lack of in vitro culture methods for Pneumocystis, this powerful bioinformatic approach has advanced our understanding of the lifestyle of P. jirovecii and the nature of its dependence on the host for survival.

Targeting β-glucans, vital components of the Pneumocystis cell wall

β-glucan is the most abundant polysaccharide in the cell wall of Pneumocystis jirovecii, which has attracted extensive attention because of its unique immunobiological characteristics. β-glucan binds to various cell surface receptors, which produces an inflammatory response and accounts for its immune effects. A deeper comprehension of the processes by Pneumocystis β-glucan recognizes its receptors, activates related signaling pathways, and regulates immunity as required. Such understanding will provide a basis for developing new therapies against Pneumocystis. Herein, we briefly review the structural composition of β-glucans as a vital component of the Pneumocystis cell wall, the host immunity mediated by β-glucans after their recognition, and discuss opportunities for the development of new strategies to combat Pneumocystis.

Burden of Serious Fungal Infections in India

Background

Fungal disease is frequent in India, but its incidence and prevalence are unclear. This review aims at defining the frequency or burden of various fungal infections in India.

Methods

A systematic review of the literature on the PubMed, Embase, and Web of Science (WOS) databases was conducted using appropriate search strings. Deterministic modeling determined annual incidence and prevalence estimates for multiple life- and sight-threatening infections with significant morbidity.

Results

Literature searches yielded >2900 papers; 434 papers with incidence/prevalence/proportion data were analyzed. An estimated 57 251 328 of the 1 393 400 000 people in India (4.1%) suffer from a serious fungal disease. The prevalence (in millions) of recurrent vulvovaginal candidiasis is 24.3, allergic bronchopulmonary aspergillosis is 2.0, tinea capitis in school-age children is 25, severe asthma with fungal sensitization is 1.36, chronic pulmonary aspergillosis is 1.74, and chronic fungal rhinosinusitis is 1.52. The annual incidence rates of Pneumocystis pneumonia (58 400), invasive aspergillosis (250 900), mucormycosis (195 000), esophageal candidiasis in HIV (266 600), candidemia (188 000), fungal keratitis (1 017 100), and cryptococcal meningitis (11 500) were also determined. Histoplasmosis, talaromycosis, mycetoma, and chromoblastomycosis were less frequent.

Conclusions

India's fungal burden is high and underappreciated in clinical practice.

Anidulafungin Treatment Blocks the Sexual Cycle of Pneumocystis murina and Prevents Growth and Survival without Rescue by an Alternative Mode of Replication

The proposed life cycle of fungi in the genus Pneumocystis has typically included both an asexual cycle via binary fission and a sexual cycle. Until recently, the strategy used for sexual replication was largely unknown, but genomic and functional assays now support a mode known as primary homothallism (self-fertilization). The question of whether an asexual cycle contributes to the growth of these fungi remains. Treatment of Pneumocystis pneumonia in immunosuppressed rodent models with the class of drugs known as echinocandins is challenging the historical concept of asexual replication. The echinocandins target 1,3-β-D-glucan (BG) synthesis resulting in death for most fungi. Because Pneumocystis species have both non-BG expressing life cycle stages (trophic forms) and BG-expressing asci, treatment with anidulafungin and caspofungin resulted in elimination of asci, with large numbers of non-BG expressing organisms remaining in the lungs. Transcriptional analyses of anidulafungin treated Pneumocystis murina-infected lungs indicated that these agents were blocking the sexual cycle. In the present study, we explored whether there was an asexual or alternative method of replication that could rescue P. murina survival and growth in the context of anidulafungin treatment. The effects of anidulafungin treatment on early events in the sexual cycle were investigated by RT-qPCR targeting specific mating genes, including mam2, map3, matMi, matPi, and matMc. Results from the in vivo and gene expression studies clearly indicated there was no rescue by an asexual cycle, supporting these fungi's reliance on the sexual cycle for survival and growth. Dysregulation of mating-associated genes showed that anidulafungin induced effects early in the mating process. IMPORTANCE The concept of a sexually obligate fungus is unique among human fungal pathogens. This reliance can be exploited for drug development and here we show a proof of principle for this unusual target. Most human fungal pathogens eschew the mammalian environment with its battery of immune responses. Pneumocystis appear to have evolved to survive in such an environment, perhaps by using sexual replication to help in DNA repair and to introduce genetic variation in its major surface antigen family because the lung is the primary environment of these pathogens. The concept of primary homothallism fits well into its chosen ecosystem, with ready mating partners expressing both mating type receptors, and a sexual cycle that can introduce beneficial genetic variation without the need for outbreeding.

A therapeutic vaccine strategy to prevent Pneumocystis pneumonia in an immunocompromised host in a non-human primate model of HIV and Pneumocystis co-infection

Introduction

Pneumocystis is a ubiquitous fungal pathogen that causes pneumonia (PCP) and pulmonary sequelae in HIV-infected individuals and other immunocompromised populations. With the success of anti-retroviral therapy for HIV-infected individuals the frequency of PCP in that population has decreased, however, PCP remains a significant cause of morbidity and mortality in individuals with hematologic and solid malignancies, and in individuals treated with immunosuppressive therapies for autoimmune diseases, and following bone marrow and solid organ transplantation. Despite the clinical need, there is no approved vaccine to prevent PCP in vulnerable populations. The ultimate goal of the field is to develop an effective vaccine that can overcome immune deficits in at risk populations and induce long-lasting protective immunity to Pneumocystis. Toward this goal, our laboratory has established a model of PCP co-infection in simian immunodeficiency virus (SIV)-infected non-human primates (NHP) and identified a recombinant protein sub-unit vaccine, KEX1, that induces robust anti-Pneumocystis immunity in immune-competent macaques that is durable and prevents PCP following simian immunodeficiency virus (SIV)-induced immunosuppression. Type I, or invariant natural killer T (iNKT) cells have the potential to provide B cell help under conditions of reduced CD4+ T cell help.

Methods

In the present study, we used the SIV model of HIV infection to address whether therapeutic vaccination with the iNKT cell-activating adjuvant α-galactosylceramide (α-GC) and KEX1 (α-GC+KEX1) can effectively boost anti-Pneumocystis humoral immunity following virus-induced immunosuppression.

Results

Immunization of antigen-experienced NHPs with α-GC+KEX1 during the early chronic phase of SIV-infection significantly boosted anti-Pneumocystis humoral immunity by increasing memory B cells and antibody titers, and enhanced titer durability during SIV-induced immunosuppression. This therapeutic vaccination strategy boosted anti-Pneumocystis immune responses during SIV-infection and contributed to protection against Pneumocystis co-infection in KEX1-vaccinated macaques.

Conclusion

These studies present a novel strategy for stimulating durable anti-Pneumocystis humoral immunity in the context of complex, chronic SIV-induced immunosuppression and may be further applied to immunization of other immunosuppressed populations, and toward other common recall antigens.

End of life decisions in immunocompromised patients with acute respiratory failure

PURPOSE

To identify patient, disease and organizational factors associated with decisions to forgo life-sustaining therapies (DFLSTs) in critically ill immunocompromised patients admitted to the intensive care unit (ICU) for acute respiratory failure.

MATERIAL AND METHODS

We performed a secondary analysis of the international EFRAIM prospective study, which enrolled 1611 immunocompromised patients with acute respiratory failure admitted to 68 ICUs in 16 countries between October 2015 and June 2016. Multivariate logistic analysis was performed to identify independent predictors of DFLSTs.

RESULTS

The main causes of immunosuppression were hematological malignancies (50%) and solid tumor (38%). Patients had a median age of 63 yo (54-71). A pulmonologist was involved in the patient management in 38% of cases. DFLSTs had been implemented in 28% of the patients. The following variables were independently associated with DFLSTs: 1) patient-related: older age (OR 1.02 per one year increase, 95% confidence interval(CI) 1.01-1.03,P < 0.001), poor performance status (OR 2.79, 95% CI 1.98-3.93, P < 0.001); 2) disease-related: shock (OR 2.00, 95% CI 1.45-2.75, P < 0.001), liver failure (OR 1.59, 95% CI 1.14-2.21, P = 0.006), invasive mechanical ventilation (OR 1.79, 95% CI 1.31-2.46, P < 0.001); 3) organizational: having a pulmonologist involved in patient management (OR 1.85, 95% CI 1.36-2.52, P < 0.001), and the presence of a critical care outreach services (OR 1.63, 95% CI 1.11-2.38, P = 0.012).

CONCLUSIONS

A DFLST is made in one in four immunocompromised patient admitted to the ICU for acute respiratory failure. Involving a pulmonologist in patient's management is associated with less non beneficial care.

Fun with fungi: a comprehensive review of common fungal organisms encountered in cytology

The ability to detect and diagnose infection is essential in the practice of cytopathology. The identification of suppurative or granulomatous inflammation should prompt careful evaluation for infection. Many of the most commonly encountered fungal organisms demonstrate characteristic microscopic appearances that allow accurate identification even with routine cytology stains, particularly when considered in the context of clinical factors such as geographic location, social history, patient immune status, and symptoms. Given the vital role cytopathologists play in the accurate diagnosis or presumptive identification of infections, this review explores the epidemiology, clinical manifestations, and morphologic features of common fungal pathogens in addition to their differential diagnoses and ancillary testing methods.

Immunogenicity and protective efficacy of a pan-fungal vaccine in preclinical models of aspergillosis, candidiasis, and pneumocystosis

Invasive fungal infections cause over 1.5 million deaths worldwide. Despite increases in fungal infections as well as the numbers of individuals at risk, there are no clinically approved fungal vaccines. We produced a "pan-fungal" peptide, NXT-2, based on a previously identified vaccine candidate and homologous sequences from Pneumocystis, Aspergillus,Candida, and Cryptococcus. We evaluated the immunogenicity and protective capacity of NXT-2 in murine and nonhuman primate models of invasive aspergillosis, systemic candidiasis, and pneumocystosis. NXT-2 was highly immunogenic and immunized animals had decreased mortality and morbidity compared to nonvaccinated animals following induction of immunosuppression and challenge with Aspergillus, Candida, or Pneumocystis. Data in multiple animal models support the concept that immunization with a pan-fungal vaccine prior to immunosuppression induces broad, cross-protective antifungal immunity in at-risk individuals.

Pneumocystis jirovecii Pneumonia Prophylaxis with Intravenous Pentamidine in Adult Allogeneic Hematopoietic Stem Cell Transplant Patients

The purpose of this single-center retrospective case series was to evaluate the efficacy and safety of 300-mg once-monthly intravenous (IV) pentamidine prophylaxis in 702 adult allogeneic hematopoietic stem cell transplant (HSCT) patients. We observed no cases of Pneumocystis jirovecii pneumonia (PJP) following IV pentamidine administration. Breakthrough Nocardia and Toxoplasma infections were observed in 7 (1%) and 5 (0.7%) patients, respectively. The most commonly reported adverse event was nausea. Monthly IV pentamidine is a reasonable alternative to trimethoprim-sulfamethoxazole (TMP-SMX).

Breathing can be dangerous: Opportunistic fungal pathogens and the diverse community of the small mammal lung mycobiome

Human lung mycobiome studies typically sample bronchoalveolar lavage or sputum, potentially overlooking fungi embedded in tissues. Employing ultra-frozen lung tissues from biorepositories, we obtained fungal ribosomal RNA ITS2 sequences from 199 small mammals across 39 species. We documented diverse fungi, including common environmental fungi such as Penicillium and Aspergillus, associates of the human mycobiome such as Malassezia and Candida, and others specifically adapted for lungs (Coccidioides, Blastomyces, and Pneumocystis). Pneumocystis sequences were detected in 83% of the samples and generally exhibited phylogenetic congruence with hosts. Among sequences from diverse opportunistic pathogens in the Onygenales, species of Coccidioides occurred in 12% of samples and species of Blastomyces in 85% of samples. Coccidioides sequences occurred in 14 mammalian species. The presence of neither Coccidioides nor Aspergillus fumigatus correlated with substantial shifts in the overall mycobiome, although there was some indication that fungal communities might be influenced by high levels of A. fumigatus. Although members of the Onygenales were common in lung samples (92%), they are not common in environmental surveys. Our results indicate that Pneumocystis and certain Onygenales are common commensal members of the lung mycobiome. These results provide new insights into the biology of lung-inhabiting fungi and flag small mammals as potential reservoirs for emerging fungal pathogens.

Targeted NGS-Based Analysis of Pneumocystis jirovecii Reveals Novel Genotypes

Pneumocystis jirovecii is an important etiological agent of pneumonia that is underdiagnosed due to the inability to culture the organism. The 2019 PERCH study identified Pneumocystis as the top fungal cause of pneumonia in HIV-negative children using a PCR cutoff of 104 copies of Pneumocystis per mL of sample in nasopharyngeal/oropharyngeal (NP/OP) specimens. Given that Pneumocystis consists of an environmental ascus form and a trophic from (the latter is the form that attaches to the lung epithelium), it is possible that life-form-specific molecular assays may be useful for diagnosis. However, to accomplish this goal, these assays require genotypic information, as the current fungal genomic data are largely from the US and Europe. To genotype Pneumocystis across the globe, we developed an NGS-based genotyping assay focused on genes expressed in asci as well as trophs using PERCH throat swabs from Africa, Bangladesh, and Thailand, as well as North American samples. The NGS panel reliably detected 21 fungal targets in these samples and revealed unique genotypes in genes expressed in trophs, including Meu10, an ascospore assembly gene; two in mitochondrial gene ATP8, and the intergenic region between COX1 and ATP8. This assay can be used for enhanced Pneumocystis epidemiology to study outbreaks but also permits more accurate RT-CPR- or CRISPR-based assays to be performed to improve the non-bronchoscopic diagnosis of this under-reported fungal pathogen.

Mucosal-Associated Invariant T Cells Accumulate in the Lungs during Murine Pneumocystis Infection but Are Not Required for Clearance

Pneumocystis is a fungal pathogen that can cause pneumonia in immunosuppressed hosts and subclinical infection in immunocompetent hosts. Mucosal-associated invariant T (MAIT) cells are unconventional lymphocytes with a semi-invariant T-cell receptor that are activated by riboflavin metabolites that are presented by the MHC-1b molecule MR1. Although Pneumocystis can presumably synthesize riboflavin metabolites based on whole-genome studies, the role of MAIT cells in controlling Pneumocystis infection is unknown. We used a co-housing mouse model of Pneumocystis infection, combined with flow cytometry and qPCR, to characterize the response of MAIT cells to infection in C57BL/6 mice, and, using MR1^−/− mice, which lack MAIT cells, to examine their role in clearing the infection. MAIT cells accumulated in the lungs of C57BL/6 mice during Pneumocystis infection and remained at increased levels for many weeks after clearance of infection. In MR1^−/− mice, Pneumocystis infection was cleared with kinetics similar to C57BL/6 mice. Thus, MAIT cells are not necessary for control of Pneumocystis infection, but the prolonged retention of these cells in the lungs following clearance of infection may allow a more rapid future response to other pathogens.

Pneumocystis jirovecii pneumonia in HIV-negative patients, a frequently overlooked problem. A case series from a large Italian center

BACKGROUND AND OBJECTIVES

Pneumocystis jirovecii pneumonia (PCP) still has substantial morbidity and mortality. For non-HIV patients, the course of infection is severe, and management guidelines are relatively recent. We collected all PCP cases (European Organization for Research and Treatment of Cancer criteria) diagnosed in HIV-negative adult inpatients in 2019-2020 at our center in northern Italy.

RESULTS

Of 20 cases, nine had microbiologic evidence of probable (real-time polymerase chain reaction, RT-PCR) and 11 proven (immunofluorescence) PCP on respiratory specimens. Half were female; the median age was 71.5 years; 14 of 20 patients had hematologic malignancies, five had autoimmune/hyperinflammatory disorders, and one had a solid tumor. RT-PCR cycle threshold (Ct) was 24-37 for bronchoalveolar lavage (BAL) and 32-39 for sputum; Ct was 24-33 on BAL proven cases. Of 20 cases, four received additional diagnoses on BAL. At PCP diagnosis, all patients were not on anti-pneumocystis prophylaxis. We retrospectively assessed prophylaxis indications: 9/20 patients had a main indication, 5/9 because of prednisone treatment ≥ 20 mg (or equivalents) for ≥4 weeks. All patients underwent antimicrobial treatment according to guidelines; 18/20 with concomitant corticosteroids. A total of 4/20 patients died within 28 days from diagnosis.

CONCLUSION

Despite appropriate treatment, PCP is still associated to high mortality (20%) among non-HIV patients. Strict adherence to prophylaxis guidelines, awareness of gray areas, and prompt diagnosis can help manage this frequently overlooked infection.

Estimated Incidence and Prevalence of Serious Fungal Infections in Morocco

Few data are published from Morocco on fungal disease, although numerous case reports attest to a wide range of conditions in the country. Here, we estimate for the first time the incidence and prevalence of serious fungal diseases in the country. Detailed literature searches in English and French were conducted for all serious fungal infections. Demographic and individual underlying condition prevalence or annual incidence were obtained from UNAIDS (HIV), WHO (TB) and other international sources. Deterministic modelling was then applied to estimate fungal disease burden. Morocco's population in 2021 was 36,561,800. Multiple publications describe various fungal diseases, but epidemiological studies are rare. The most frequent serious fungal infections were tinea capitis (7258/100,000) and recurrent vulvovaginal candidiasis (2794/100,000 females). Chronic pulmonary aspergillosis is also common at a prevalence of 19,290 (53/100,000) because of the relatively high rate of tuberculosis. The prevalence of asthma in adults exceeds one million, of whom fungal asthma (including allergic bronchopulmonary aspergillosis (ABPA)) probably affects 42,150 (115/100,000). Data are scant on candidaemia (estimated at 5/100,000), invasive aspergillosis (estimated at 4.1/100,000), HIV-related complications such as cryptococcal meningitis and Pneumocystis pneumonia and mucormycosis. Fungal keratitis is estimated at 14/100,000). Mycetoma and chromoblastomycosis are probably rare. Fungal disease is probably common in Morocco and diagnostic capacity is good in the teaching hospitals. These estimates need confirmation with methodologically robust epidemiological studies.

Clinical impact of pneumothorax in patients with Pneumocystis jirovecii pneumonia and respiratory failure in an HIV-negative cohort

Background

Pneumocystis jirovecii pneumonia (PCP) with acute respiratory failure can result in development of pneumothorax during treatment. This study aimed to identify the incidence and related factors of pneumothorax in patients with PCP and acute respiratory failure and to analyze their prognosis.

Methods

We retrospectively reviewed the occurrence of pneumothorax, including clinical characteristics and results of other examinations, in 119 non-human immunodeficiency virus patients with PCP and respiratory failure requiring mechanical ventilator treatment in a medical intensive care unit (ICU) at a tertiary-care center between July 2016 and April 2019.

Results

During follow up duration, twenty-two patients (18.5%) developed pneumothorax during ventilator treatment, with 45 (37.8%) eventually requiring a tracheostomy due to weaning failure. Cytomegalovirus co-infection (odds ratio 13.9; p = 0.013) was related with occurrence of pneumothorax in multivariate analysis. And development of pneumothorax was not associated with need for tracheostomy and mortality. Furthermore, analysis of survivor after 28 days in ICU, patients without pneumothorax were significantly more successful in weaning from mechanical ventilator than the patients with pneumothorax (44% vs. 13.3%, p = 0.037). PCP patients without pneumothorax showed successful home discharges compared to those who without pneumothorax (p = 0.010).

Conclusions

The development of pneumothorax increased in PCP patient with cytomegalovirus co-infection, pneumothorax might have difficulty in and prolonged weaning from mechanical ventilators, which clinicians should be aware of when planning treatment for such patients.

Effectiveness of a real-time PCR for diagnosis of Pneumocystis pneumonia in immunocompromised patients - Experience from a tertiary care center, India

Pneumocystis jirovecii pneumonia (PCP) is a life-threatening fungal infection in immunocompromised patients. Traditionally, the laboratory diagnosis of PCP relied on the visualization of organisms by microscopy as Pneumocystis cannot be readily cultured in the laboratory. The polymerase chain reaction (PCR) method is preferred over the conventional microscopic methods as PCR is rapid and found to have higher sensitivity. This retrospective study aimed to analyze the diagnostic value of a real-time PCR (qPCR) for routine diagnosis of PCP in immunocompromised patients with various underlying conditions. The qPCR targets a 121 bp fragment of P.jirovecii mitochondrial large subunit rRNA gene. The study was conducted in a 2600-bed tertiary care hospital between January and December 2019. All patients whose respiratory samples were tested for PCP by qPCR were included. The clinical diagnosis was made for each patient and categorized into PCP and non-PCP based on multi-component clinical criteria by a multi-disciplinary team. The performance characteristics of qPCR were analyzed using clinical diagnosis as the reference. A total of 339 respiratory samples from 289 patients were tested for PCP by qPCR during the study period. The overall sensitivity and specificity of qPCR were 84.75% (95% CI, 73.01% to 92.78%) and 96.1% (95% CI, 92.7 to 98.2), respectively. The sensitivity was slightly higher among HIV-infected patients (91%) than the non- HIV group (81%). The PCR exhibited higher sensitivity in bronchoalveolar lavage (BAL) (94%) than in sputum samples (81%). The colonization can be ruled out with the cycle threshold (C_T) value of below 34 with a sensitivity and specificity of 100% and 78%, respectively. The real-time PCR showed good sensitivity and specificity for routine diagnosis of PCP in patients with various underlying conditions. In addition, a cut-off C_T value (≤ 34) was determined to exclude colonization from active pneumonia.

Comparison of the PneumoGenius® and RealStar® Pneumocystis jirovecii PCR CE-IVD assays with a lab developed test for the detection of Pneumocystis jirovecii

Pneumocystis jirovecii (Pj) is a fungal pathogen that can cause severe and potential fatal pneumonia (Pneumocystis pneumonia, PCP) in immunocompromised patients. Microbiological diagnosis is necessary to confirm PCP, for which mainly real-time PCR assays are used by detecting Pj from bronchoalveolar lavage (BAL) specimens. In this study, we evaluate the performance of the CE-IVD PneumoGenius® assay and CE-IVD RealStar® Pneumocystis jirovecii PCR assay in comparison to the lab developed test (LDT) that is used in routine diagnostics. Comparison was done by including 100 BAL specimens: 25 retrospective specimens, selected based on results obtained with LDT (15 positive/10 negative), and 75 prospectively collected specimens. LDT (targeting MSG) was performed according to local procedures and the PneumoGenius® (targeting mtLSU and DHPS fas) and RealStar® assays (targeting mtLSU) according to manufacturer's instructions. Combining results of retrospective and prospective analysis, sensitivity was 69.7%, 100% and 100% for the LDT, PneumoGenius® and RealStar®, respectively. Specificity was 100% for LDT and Pneumogenius®, whereas RealStar® showed a specificity of 97%. Correlation of fungal loads found with the PneumoGenius® and RealStar® assays was high (R2: 0.98). The PneumoGenius® and RealStar® assays performed comparable, and both showed high sensitivity in comparison to the LDT. For optimal diagnosis of PCP, the LDT has to be replaced by another, more sensitive assay.

Pneumocystis jirovecii pneumonia in breast cancer mimicking SARS-CoV-2 pneumonia during pandemic

Pneumocystis jirovecii pneumonia (PJP) is one of the most common HIV-related opportunistic infection. Apart from HIV patients, subjects treated with an associated therapy of high doses glucocorticoids and immunosuppressive drugs should be considered at risk. SARS-CoV-2 has become worldly known as the responsible of the pandemic that hit the world in late 2019 and that is still ongoing. Italy, and especially Brescia, was one of the area most struck by the pandemic, with a significant number of cases being reported (more than 112,648 as of October 2021). The diagnosis of SARS-CoV-2 is mainly based on RT-PCR assays performed on nasopharyngeal swab, X-ray of the chest and clinical manifestations. We describe two cases of PJP in two immunocompromised patients with breast cancer who were admitted at Spedali Civili of Brescia hospital, Italy, with an initial diagnosis of SARS-CoV-2 pneumonia, despite testing negative to RT-PCR on nasopharyngeal swabs. We also retrospectively reassessed all cases of pneumonia deemed as SARS-CoV-2-related upon admission and then converted to PJP as the final diagnosis. We describe the two following cases to emphasize that clinicians should always be alert about PJP, even during the SARS-CoV-2 pandemic, and avoid focusing on COVID-19 exclusively. PJP should always be considered as a differential diagnosis in patients, particularly if immunosuppressed, with an X-ray or TC of the chest suggestive of interstitial pneumonia and a negative SARS-CoV-2 RT-PCR on nasopharyngeal swabs.

Factors associated with Pneumocystis colonization and circulating genotypes in chronic obstructive pulmonary disease patients with acute exacerbation or at stable state and their homes

Pneumocystis jirovecii colonization is frequent during chronic obstructive pulmonary disease (COPD) and patients constitute potential contributors to its interhuman circulation. However, the existence of an environmental reservoir cannot be excluded. We assessed the prevalence and factors associated with Pneumocystis colonization during COPD, and studied circulation between patients and their domestic environment. Pneumocystis molecular detection and mtLSU genotyping were performed in oro-pharyngeal washes (OPW) sampled in 58 patients with COPD acute exacerbation, and in indoor dust, sampled in patients' homes using electrostatic dust collectors (EDCs). Lung and systemic inflammation was assessed. Pneumocystis carriage was evaluated in 28 patients after 18 months at stable state. Pneumocystis was detected in 11/58 OPWs during exacerbation (19.0%). Colonized patients presented a significantly lower body mass index, and higher serum IL-17 and CD62P. One patient presented positive detection of typable isolates in both OPW and EDC, with both isolates harboring mtLSU genotype 3. Pneumocystis genotype 1 was further detected in EDCs from three non-colonized patients and one colonized patient with non-typable isolate. Genotypes 1 and 2 were predominant in clinical isolates (both 42%), with genotype 3 representing 16% of isolates. Pneumocystis was detected in 3/28 patients at stable state (10.7%). These data suggest that Pneumocystis colonization could be facilitated by a lower BMI and be related to acute alteration of lung function during COPD exacerbation. It also suggests Th17 pathway and platelet activation could be involved in the anti-Pneumocystis response during colonization. Last, Pneumocystis detection in EDCs supports its potential persistence in indoor dust.

LAY SUMMARY

Chronic obstructive pulmonary disease patients tend to be more frequently colonized by Pneumocystis during exacerbation (19.0%) than at stable state (10.7%). Factors associated with colonization include lower BMI, higher IL-17, and CD62P. Pneumocystis detection in patients' dwellings suggests potential persistence in indoor dust.