Outbreak-Causing Fungi: Pneumocystis jirovecii

Pneumocystis jirovecii pneumonia (PCP) is an important cause of morbidity in immunocompromised patients, with a higher mortality in non-HIV than in HIV patients. P. jirovecii is one of the rare transmissible pathogenic fungi and the only one that depends fully on the host to survive and proliferate. Transmissibility among humans is one of the main specificities of P. jirovecii. Hence, the description of multiple outbreaks raises questions regarding preventive care management of the disease, especially in the non-HIV population. Indeed, chemoprophylaxis is well codified in HIV patients but there is a trend for modifications of the recommendations in the non-HIV population. In this review, we aim to discuss the mode of transmission of P. jirovecii, identify published outbreaks of PCP and describe molecular tools available to study these outbreaks. Finally, we discuss public health and infection control implications of PCP outbreaks in hospital setting for in- and outpatients.

Genetic Polymorphisms of Superoxide Dismutase Locus of Pneumocystis jirovecii in Spanish Population

Objective:Pneumocystis pneumonia remains a major opportunistic infection in immunocompromised patients worldwide. Colonization with Pneumocystis jirovecii has recently gained attention as an important issue for understanding the complete cycle of human Pneumocystis infection. P. jirovecii Superoxide Dismutase (SOD) gene could be a molecular target with high clinical relevance, but the epidemiological information about SOD genotypes distribution is scarce. The aim of this work was to provide information about the prevalence of genotypes of Pneumocystis SOD among Spanish patients and to describe possible differences between colonized and Pneumocystis pneumonia patients.

Methods: we developed a cross-sectional study analyzing broncho-alveolar lavage fluid samples from 30 Pneumocystis pneumonia patients, 30 colonized patients, and 20 controls using a nested PCR protocol designed to amplify the sodA gene of P. jirovecii. The diagnostic yield of SOD Nested PCR was evaluated against the routine practice of mtLSUrRNA Nested PCR, which is considered the gold standard.

Results: SOD locus was amplified in 90% of Pneumocystis pneumonia patients, 10% of colonized patients, and none of controls. Genotype SOD1 was observed in 11 cases (52.4%) and genotype SOD2 in 10 cases (47.6%). Genotype SOD2 was observed only in Pneumocystis pneumonia patients while the genotype SOD1 was observed in both colonized and Pneumocystis pneumonia patients.

Conclusions: This study provides epidemiological information about SOD genotypes distribution in Spain, showing a low genetic diversity and a predominant presence of genotype SOD1 in colonized patients. SOP Nested PCR was more sensitive and accurate assay in Pneumocystis pneumonia patients than in colonized individuals.

Pneumocystis jirovecii in Spanish Patients With Heart Failure

Objective:Pneumocystis colonization is frequent in patients with chronic obstructive pulmonary disease (COPD) producing local and systemic inflammation. Heart failure is also a common comorbidity among patients with COPD. Heart failure is a chronic, frequent, and disabling condition with high morbidity and mortality, but with a modifiable course where endothelial dysfunction and pulmonary arterial hypertension have great importance. Animal models have shown that Pneumocystis infection can cause relevant functionally changes in vascular responses in the lung, promoting the development of pulmonary hypertension. Pneumocystis colonization could be a hidden cause of worsening heart failure through it capacity to induce inflammatory response with subsequent endothelial dysfunction and pulmonary hypertension. The aim of the present study was to investigate the prevalence of Pneumocystis jirovecii colonization in heart failure patients and its possible association with reduced or preserved ejection fraction.

Methods: A cross-sectional study was carried out including 36 heart failure patients and 36 control cases. Identification of P. jirovecii colonization was performed by means of molecular techniques in oropharyngeal washing.

Results:Pneumocystis-DNA was identified in oropharyngeal washing in 1 (2.7%) of 36 heart failure patients and in 3 (8.3%) of 36 controls.

Conclusions:Pneumocystis colonization does not seem to have a role in the pathophysiology of heart failure.

Changing Trends in the Epidemiology and Risk Factors of Pneumocystis Pneumonia in Spain

Objective: The information about the epidemiology of Pneumocystis pneumonia (PcP) in Europe is scarce, and in Spain there are only data nationwide on patients with HIV infection. This study has been carried out with the aim of knowing in our country the current epidemiological spectrum and the risk factors of PcP.

Methods: Observational, descriptive transversal study that included all patients admitted in Spain with diagnosis upon discharge of PcP registered in the National Health System's Hospital Discharge Records Database of Spain, between 2008 and 2012.

Results: Four thousand five hundred and fifty four cases of PcP were reported, 1,204 (26.4%) in HIV-negative patients. During the study period, mean annual incidence (cases per million) was 19.4, remaining globally stable, increasing from 4.4 to 6.3 in HIV-negative patients and decreasing from 15.5 to 13.4 among HIV-infected patients. Risk factors were identified in 85.5% of HIV-negative cases, the most frequent being hematological neoplams (29%), chronic lung diseases (15.9%), and non-hematological cancers (14.9%). Mean mortality and hospitalization cost were high (25.5% and 12,000 euros, respectively).

Conclusions: The results of this first nationwide study in Spain allow a change in the misconception that, after the AIDS epidemic, PcP is an infrequent disease, showing that today it is an emerging problem in patients without HIV infection. These findings underlines the need for increased efforts toward a better characterization of risk groups to improve prophylactic strategies and reduce the burden of disease.

Transcriptomic and Proteomic Approaches to Finding Novel Diagnostic and Immunogenic Candidates in Pneumocystis

Pneumocystis pneumonia is the most common serious opportunistic infection in patients with HIV/AIDS. Furthermore, Pneumocystis pneumonia is a feared complication of the immunosuppressive drug regimens used to treat autoimmunity, malignancy, and posttransplantation rejection. With an increasing at-risk population, there is a strong need for novel approaches to discover diagnostic and vaccine targets. There are multiple challenges to finding these targets, however. First, Pneumocystis has a largely unannotated genome. To address this, we evaluated each protein encoded within the Pneumocystis genome by comparisons to proteins encoded within the genomes of other fungi using NCBI BLAST. Second, Pneumocystis relies on a multiphasic life cycle, as both the transmissible form (the ascus) and the replicative form (the trophozoite [troph]) reside within the alveolar space of the host. To that end, we purified asci and trophs from Pneumocystis murina and utilized transcriptomics to identify differentially regulated genes. Two such genes, Arp9 and Sp, are differentially regulated in the ascus and the troph, respectively, and can be utilized to characterize the state of the Pneumocystis life cycle in vivo Gsc1, encoding a β-1,3-glucan synthase with a large extracellular domain previously identified using surface proteomics, was more highly expressed on the ascus form of Pneumocystis GSC-1 ectodomain immunization generated a strong antibody response that demonstrated the ability to recognize the surface of the Pneumocystis asci. GSC-1 ectodomain immunization was also capable of reducing ascus burden following primary challenge with Pneumocystis murina Finally, mice immunized with the GSC-1 ectodomain had limited fungal burden following natural transmission of Pneumocystis using a cohousing model.IMPORTANCE The current report enhances our understanding of Pneumocystis biology in a number of ways. First, the current study provided a preliminary annotation of the Pneumocystis murina genome, addressing a long-standing issue in the field. Second, this study validated two novel transcripts enriched in the two predominant life forms of Pneumocystis These findings allow better characterization of the Pneumocystis life cycle in vivo and could be valuable diagnostic tools. Furthermore, this study outlined a novel pipeline of -omics techniques capable of revealing novel antigens (e.g., GSC-1) for the development of vaccines against Pneumocystis.

Severe hypercalcemia preceding a diagnosis of Pneumocystis jirovecii pneumonia in a liver transplant recipient

Background

Incidence of the opportunistic infection Pneumocystis jirovecii pneumonia (PJP) in solid organ transplant patients ranges from 5 to 15% with a mortality of up to 38%.

Case presentation

We present a liver transplant recipient who developed hypoxemic respiratory failure related to PJP soon after treatment for allograft rejection. His presentation was preceded by severe hypercalcemia of 14.6 mg/dL and an ionized calcium of 1.7 mmol/L which remained elevated despite usual medical management and eventually required renal replacement therapy. As approximately 5% of PJP cases have granulomas, here we review the role of pulmonary macrophages and inflammatory cytokines in the pathophysiology of granuloma-mediated hypercalcemia. We also discuss the interpretation of our patient’s laboratory studies, response to medical therapy, and clinical risk factors which predisposed him to PJP.

Conclusions

It is important for clinicians to consider PJP as an etiology of granulomatous pneumonia and non-parathyroid hormone mediated hypercalcemia in chronically immunosuppressed organ transplant recipients for timely diagnosis and management.

[Study on pathogenicity of Pneumocystis and its association with development of chronic obstructive pulmonary disease]

OBJECTIVE

To investigate the pathogenicity of Pneumocystis and its association with the development of chronic obstructive pulmonary disease (COPD).

METHODS

The rat model of Pneumocystis pneumonia (PCP) was induced by intraperitoneal injection with dexamethasone, which was confirmed by pathogenic detection. The pathologic changes of rat lung specimens were examined using conventional HE staining, and the expression of inflammatory cells were detected by flow cytometry in bron-choalveolar lavage fluid (BALF) and splenic tissues of the rat model of PCP. In addition, the serum levels of matrix metalloproteinase 8 (MMP-8) and MMP-9 were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Fusion and atrophy of alveolar spaces and hyperplasia of lung tissue were seen in the lung specimens of the rat model of PCP, and foam-like alveolar exudates and infiltration of inflammation cells were observed in the alveolar space, while severe infections exhibited consolidation of lung, which was similar to pathological features of COPD. The counts of CD8⁺ T lymphocytes (t = -7.920 and -12.514, P < 0.01), macrophages (t = -7.651 and -14.590, P < 0.01) and granulocytes (t = -10.310 and -16.578, P < 0.01) significantly increased and the counts of CD4⁺ T lymphocytes (t = 6.427 and 18.579, P < 0.01) significantly reduced in the BALF and splenic specimens of the rats with PCP relative to those without PCP. In addition, higher serum MMP-8 (t = -8.689, P < 0.01) and MMP-9 levels (t = -7.041, P < 0.01) were measured in rats with PCP than in those without PCP.

CONCLUSIONS

Pneumocystis infection may be associated with the development and progression of COPD.

Immunization with Pneumocystis recombinant KEX1 induces robust and durable humoral responses in immunocompromised non-human primates

Infection with the opportunistic fungal pathogen, Pneumocystis jirovecii causes life-threatening pneumonia in immunocompromised individuals. In addition to HIV-1 infected patients, individuals at risk of Pneumocystis infection include those receiving immunosuppressive therapies due to transplantation, cancer or autoimmune disease. Antibiotic treatment is not always successful, and it does not prevent obstructive lung disease after clearance of the pathogen. Therefore, it is essential to develop therapeutic alternatives that are more effective against PCP. We reported that Pneumocystis recombinant protein KEX1 induces protective immunity against the development of PCP in a non-human primate model of HIV-induced immunosuppression. In this study, we tested the immunogenicity KEX1 immunization of healthy rhesus macaques and the durability of these responses during drug-induced immunosuppression using tacrolimus (FK506) and methylprednisolone. We observed that vaccination with KEX1 prior to the start of the immunosuppressive regimen generated a robust and long-lasting antibody response that was maintained throughout the immunosuppressive treatment. Furthermore, boosting with KEX1 during immunosuppression induced recall of memory responses against recombinant KEX1. The durability of the anti-KEX1 response and the ability to induce a recall response during immunosuppressive therapy provide a proof-of-concept data supporting further investigation of the KEX1 as a prophylactic vaccine to prevent PCP in drug-induced immunosuppression. This approach provides fundamental knowledge for the elaboration of therapeutic and prophylactic alternatives for PCP in patients undergoing severe immunosuppressive therapy.

Evolutionary history of Pneumocystis fungi in their African rodent hosts

Pneumocystis is a genus of parasitic fungi infecting lung tissues in a wide range of mammal species, displaying a strong host specificity and patterns of co-speciation with their hosts. However, a recent study on Asiatic murids challenged these patterns reporting several Pneumocystis lineages/species shared by different host species or even genera in the Rattini and Murini tribes. Here we screened lung samples of 27 species of African rodents from five families for the presence of Pneumocystis DNA. Using reconstructed multi-locus phylogenies of both hosts and parasites, we tested the hypothesis of their co-evolution. We found that Pneumocystis is widespread in African rodents, detected in all but seven screened host species, with species-level prevalence ranging from 5.9 to 100%. Several host species carry pairs of highly divergent Pneumocystis lineages/species. The retrieved co-phylogenetic signal was highly significant (p = .0017). We found multiple co-speciations, sorting events and two host-shift events, which occurred between Murinae and Deomyinae hosts. Comparison of genetic distances suggests higher substitution rates for Pneumocystis relative to the rodent hosts on neutral loci and slower rates on selected ones. We discuss life-history traits and population dynamics factors which could explain the observed results.

CD4+ T Cell Regulation of Antibodies Cross-Reactive with Fungal Cell Wall-Associated Carbohydrates after Pneumocystis murina Infection

Pneumocystis pneumonia is a life-threatening opportunistic fungal infection observed in individuals with severe immunodeficiencies, such as AIDS. Molecules with the ability to bind β-glucan and signal at Fcγ receptors enhance defense against Pneumocystis f. sp. murina, though it is unclear whether antibodies reactive with fungal cell wall carbohydrates are induced during Pneumocystis infection. We observed that systemic and lung mucosal immunoglobulins cross-reactive with β-glucan and chitosan/chitin are generated after Pneumocystis infection, with increased quantities within the lung mucosal fluid after challenge. While IgG responses against Pneumocystis protein antigens are markedly CD4⁺ T cell dependent, CD4⁺ T cell depletion did not impact quantities of IgG cross-reactive with β-glucan or chitosan/chitin in the serum or mucosa after challenge. Notably, lung mucosal quantities of IgA cross-reactive with β-glucan or chitosan/chitin are decreased in the setting of CD4⁺ T cell deficiency, occurring in the setting of concurrent reduced quantities of active transforming growth factor β, while mucosal IgM is significantly increased in the setting of CD4⁺ T cell deficiency. Interleukin-21 receptor deficiency does not lead to reduction in mucosal IgA reactive with fungal carbohydrate antigens after Pneumocystis challenge. These studies demonstrate differential CD4⁺ T cell-dependent regulation of mucosal antibody responses against β-glucan and chitosan/chitin after Pneumocystis challenge, suggesting that different B cell subsets may be responsible for the generation of these antibody responses, and suggest a potential immune response against fungi that may be operative in the setting of CD4⁺ T cell-related immunodeficiency.

The Contribution of Host Cells to Pneumocystis Immunity: An Update

Pneumocystis is a ubiquitous atypical fungus that is distributed globally. The genus comprises morphologically similar but genetically heterogeneous species that have co-evolved with specific mammalian hosts as obligate intra-pulmonary pathogens. In humans, Pneumocystis jirovecii is the causative organism of Pneumocystis pneumonia (PCP) in immunocompromised individuals, a serious illness frequently leading to life-threatening respiratory failure. Initially observed in acquired immunodeficiency syndrome (AIDS) patients, PCP is increasingly observed in immunocompromised non-AIDS patients. The evolving epidemiology and persistently poor outcomes of this common infection will require new strategies for diagnosis and treatment. A deeper understanding of host immune responses and of the cells that mediate them will improve the chance of developing new treatment strategies. This brief review provides an update on recent studies on the role of host immunity against Pneumocystis.

A case of Pneumocystis pneumonia, with a granulomatous response and vitamin D-mediated hypercalcemia, presenting 13 years after renal transplantation

Vitamin D-mediated hypercalcemia is an uncommon complication of Pneumocystis infection. A granulomatous response resulting from Pneumocystis infection is also atypical. In this report, we describe an exceptional case of granulomatous Pneumocystis pneumonia associated with vitamin D-mediated hypercalcemia, in a patient who presented unusually late after renal transplantation. The patient's hypercalcemia resolved with treatment of the infection.

Site-Directed Mutagenesis of the 1,3-β-Glucan Synthase Catalytic Subunit of Pneumocystis jirovecii and Susceptibility Assays Suggest Its Sensitivity to Caspofungin

The echinocandin caspofungin inhibits the catalytic subunit Gsc1 of the enzymatic complex synthesizing 1,3-β-glucan, an essential compound of the fungal wall. Studies with rodents showed that caspofungin is effective against Pneumocystis asci. However, its efficacy against asci of Pneumocystis jirovecii, the species infecting exclusively humans, remains controversial. The aim of this study was to assess the sensitivity to caspofungin of the P. jirovecii Gsc1 subunit, as well as of those of Pneumocystis carinii and Pneumocystis murina infecting, respectively, rats and mice. In the absence of an established in vitro culture method for Pneumocystis species, we used functional complementation of the Saccharomyces cerevisiae gsc1 deletant. In the fungal pathogen Candida albicans, mutations leading to amino acid substitutions in Gsc1 confer resistance to caspofungin. We introduced the corresponding mutations into the Pneumocystis gsc1 genes using site-directed mutagenesis. In spot dilution tests, the sensitivity to caspofungin of the complemented strains decreased with the number of mutations introduced, suggesting that the wild-type enzymes are sensitive. The MICs of caspofungin determined by Etest and YeastOne for strains complemented with Pneumocystis enzymes (respectively, 0.125 and 0.12 μg/ml) were identical to those upon complementation with the enzyme of C. albicans, for which caspofungin presents low MICs. However, they were lower than the MICs upon complementation with the enzyme of the resistant species Candida parapsilosis (0.19 and 0.25 μg/ml). Sensitivity levels of Gsc1 enzymes of the three Pneumocystis species were similar. Our results suggest that P. jirovecii is sensitive to caspofungin during infections, as are P. carinii and P. murina.

Pneumocystis jiroveci pneumonia in kidney and simultaneous pancreas kidney transplant recipients in the present era of routine post-transplant prophylaxis: risk factors and outcomes

BACKGROUND

The goal of this study was to identify predictors for development of Pneumocystis jirovecii pneumonia (PJP) in kidney and simultaneous kidney and pancreas transplant recipients in the present era of universal primary prophylaxis.

METHODS

We reviewed adult recipients of kidney transplant or simultaneous pancreas and kidney transplant at the University of Wisconsin between January 1, 1994 and December 31, 2016. Patients diagnosed with PJP during this time frame were included. Controls were randomly selected from among those whose post-transplant course was not complicated by PJP, matched on time since transplant through incidence density sampling with a 3:1 ratio.

RESULTS

28 (0.45%) of 6270 recipients developed PJP between 1994 and 2016. Median time since transplant was 4.6 years (interquartile range (IQR): 1.4-9.6 years). Affected recipients were older, had more HLA mismatches, and were more likely to have had BK viremia, CMV viremia and invasive fungal infections than matched controls. CMV viremia remained the only significant risk factor in multivariate analysis, and was a strong predictor (OR 6.27; p = 0.002). Ninety percent of the cases with prior CMV viremia had been diagnosed in the year preceding the diagnosis of PJP; among these, median time from diagnosis of CMV to diagnosis of PJP was 3.4 months (IQR: 1.74-11.5 months) and median peak CMV viral load prior to diagnosis of PJP was 3684.5 IU/mL (IQR: 1034-93,300 IU/mL). Additionally, 88.9% of patients with CMV in the preceding year had active infection at time of PJP diagnosis. Patient and graft survival were significantly worse at 2 years in recipients with PJP than our control group (42.4% vs. 88.5, and 37.9% vs. 79.9%; p < 0.001).

CONCLUSIONS

Despite the low overall incidence of PJP in the era of universal prophylaxis, outcomes are poor. We suggest extending or re-initiating PJP prophylaxis for at least 6 months in the setting of CMV viremia due to the relatively low risk of therapy and potential significant impact on disease prevention.

The Relationship between Pneumocystis Infection in Animal and Human Hosts, and Climatological and Environmental Air Pollution Factors: A Systematic Review

BACKGROUND

Over the past decade, there has been rising interest in the interaction of Pneumocystis with the environment. This interest has arisen in part from the demonstration that environmental factors have important effects on the viability and transmission of microbes, including Pneumocystis. Environmental factors include climatological factors such as temperature, humidity, and precipitation, and air pollution factors including carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate matter.

METHODS

We undertook a systematic review in order to identify environmental factors associated with Pneumocystis infection or PCP, and their effects on human and animal hosts.

RESULTS

The systematic review found evidence of associations between Pneumocystis infection in animal and human hosts, and climatological and air pollution factors. Data from human studies infers that rather than a seasonal association, presentation with PCP appears to be highest when the average temperature is between 10 and 20°C. There was evidence of an association with hospitalization with PCP and ambient air pollution factors, as well as evidence of an effect of air pollution on both systemic and bronchoscopic lavage fluid humoral responses to Pneumocystis. Interpretation of human studies was confounded by possible genetically-determined predisposition to, or protection from infection.

CONCLUSIONS

This systematic review provides evidence of associations between Pneumocystis infection in both animal and human hosts, and climatological and environmental air pollution factors. This information may lead to an improved understanding of the conditions involved in transmission of Pneumocystis in both animal and human hosts. Such knowledge is critical to efforts aimed at prevention.

Chloroquine Analogues as Leads against Pneumocystis Lung Pathogens

The impact of Pneumocystis pneumonia (PcP) on morbidity and mortality remains substantial for immunocompromised individuals, including those afflicted by HIV infection, organ transplantation, cancer, autoimmune diseases, or subject to chemotherapy or corticosteroid-based therapies. Previous work from our group has shown that repurposing antimalarial compounds for PcP holds promise for treatment of this opportunistic infection. Following our previous discovery of chloroquine analogues with dual-stage antimalarial action both in vitro and in vivo, we now report the potent action of these compounds on Pneumocystis carinii in vitro Identification of chloroquine analogues as anti-PcP leads is an unprecedented finding.

The clinical impact of pneumocystis and viral PCR testing on bronchoalveolar lavage in immunosuppressed patients

Introduction

Pulmonary infiltrates in immunosuppressed patients are common. Yields from bronchoscopy with bronchoalveolar lavage (BAL) has been reported to be between 31 and 65%. The clinical impact of pneumocystis and viral Polymerase chain reaction (PCR) testing on BAL has not been extensively evaluated in a mixed immunosuppressed patient population.

Methods

We performed a retrospective chart review of immunosuppressed adults with pulmonary infiltrates who underwent BAL at the University of Rochester Medical Center. Only one BAL per patient was included. We compared the rate of positive PCR testing to conventional testing. We then investigated factors associated with positive PCR testing. Finally, we assessed for changes in antimicrobial therapy after bronchoscopy.

Results

Three hundred and fifty-nine patients underwent BAL with 249 patients having pneumocystis PCR testing and 142 having viral PCR testing. Pneumocystis identification occurred in 43 patients and viral species identification occurred in 56 patients. PCR testing increased pneumocystis identification compared to microscopy, 14% vs. 5%, p = 0.01, and viral identification compared to culture, 25% vs. 6%, p = 0.0001. Of the patients with positive pneumocystis PCR testing 49% had antibiotics stopped, 66% were started on anti-pneumocystis therapy, and only 6% did not receive treatment. There was no difference in the number of patients with antibiotics stopped based on viral PCR testing results.

Discussion

PCR testing increases BAL yield in immunosuppressed patients compared to conventional testing. Pneumocystis identified by PCR only may cause a self-limited infection and may not require antimicrobial therapy. PCR testing should be included in the evaluation of pulmonary infiltrates in immunosuppressed patients.

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Polymerase chain reaction testing has increased bronchoscopy yield.

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Pneumocystis is now being identified in non-HIV/AIDS with negative microscopy.

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Viruses are identified during bronchoscopy that were missed during nasal testing.

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Antimicrobial therapies are being changed based on testing results.

Real-time PCR assay for screening Pneumocystis in free-living wild squirrels and river rats in Italy

We used a real-time PCR (rtPCR) targeting a 150-bp amplicon of the mitochondrial small subunit of ribosomal RNA (mtSSU rRNA) to screen for Pneumocystis DNA in lungs of wild squirrels ( Callosciurus finlaysonii, n = 85) and river rats ( Myocastor coypus, n = 43) in Italy. The rtPCR revealed Pneumocystis DNA in 20 of 85 (24%) squirrels and in 35 of 43 (81%) river rats, and was more sensitive than a nested PCR that targets a portion of the mtSSU rRNA and the mitochondrial large subunit of rRNA (mtLSU rRNA). Phylogenetic analysis based on mtSSU rRNA and mtLSU rRNA sequences showed distinct Pneumocystis sequence types in these rodents. The rtPCR assay should be reliable for screening large populations for this potential pathogen, thereby allowing cost-effective monitoring of the disease in wild animals.

Evaluation of laboratory disturbance risk when adding low-dose cotrimoxazole for PJP prophylaxis to regimens of high-grade glioma patients taking RAAS inhibitors

BACKGROUND

Cotrimoxazole is associated with the development of hyponatremia, hyperkalemia and elevated serum creatinine, especially when combined with inhibitors of the renin-angiotensin-aldosterone system (RAAS). Pneumocystis jirovecii pneumonia (PJP) prophylaxis is the standard of care for high-grade glioma (HGG) patients receiving temozolomide concurrently with radiotherapy, low-dose cotrimoxazole being the preferred agent. Many of these patients are also taking renin-angiotensin-aldosterone system inhibitors, however the risk of significant laboratory disturbance in these patients remains undescribed.

OBJECTIVE

We evaluated whether high-grade glioma patients taking renin-angiotensin-aldosterone system inhibitors receiving low-dose cotrimoxazole for Pneumocystis jirovecii pneumonia prophylaxis are at additional risk of laboratory disturbances in comparison with their non-renin-angiotensin-aldosterone system counterparts.

METHODS

We conducted a retrospective chart review of adult neuro-oncology patients treated for WHO Grade III or IV glioma between 2013 and 2016. Patient serum Na, K, creatinine, and eGFR were compared (renin-angiotensin-aldosterone system vs. non-renin-angiotensin-aldosterone system) using the chi-square test. Binary logistic regression analysis was then performed to account for differences between cohorts.

RESULTS

Of 63 patients (35 non-renin-angiotensin-aldosterone system, 28 renin-angiotensin-aldosterone system), patients in the renin-angiotensin-aldosterone system cohort were more likely to experience a laboratory disturbance (odds ratio=3.17, p = 0.03). Overall, these disturbances were moderate, but were slightly more common and slightly more severe in the renin-angiotensin-aldosterone system cohort.

CONCLUSION

Adding low-dose cotrimoxazole for Pneumocystis jirovecii pneumonia prophylaxis to the regimens of patients with high-grade glioma taking renin-angiotensin-aldosterone system inhibitors increases the risk of laboratory disturbances. While these are generally moderate, some patients are at risk of significant electrolyte abnormalities requiring intervention.

Genetic diversity of Pneumocystis jirovecii from a cluster of cases of pneumonia in renal transplant patients: Cross-sectional study

Pneumocystis jirovecii can cause severe potentially life-threatening pneumonia (PCP) in kidney transplant patients. Prophylaxis of patients against PCP in this setting is usually performed during 6 months after transplantation. The aim of this study is to describe the molecular epidemiology of a cluster of PCP in renal transplant recipients in Brazil. Renal transplant patients who developed PCP between May and December 2011 had their formalin-fixed paraffin-embedded (FFPE) lung biopsy samples analysed. Pneumocystis jirovecii 23S mitochondrial large subunit of ribosomal RNA (23S mtLSU-rRNA), 26S rRNA, and dihydropteroate synthase (DHPS) genes were amplified by polymerase chain reaction (PCR), sequenced, and analysed for genetic variation. During the study period, 17 patients developed PCP (only four infections were documented within the first year after transplantation) and six (35.3%) died. Thirty FFPE samples from 11 patients, including one external control HIV-infected patient, had fungal DNA successfully extracted for further amplification and sequencing for all three genes. A total of five genotypes were identified among the 10 infected patients. Of note, four patients were infected by more than one genotype and seven patients were infected by the same genotype. DNA extracted from FFPE samples can be used for genotyping; this approach allowed us to demonstrate that multiple P. jirovecii strains were responsible for this cluster, and one genotype was found infecting seven patients. The knowledge of the causative agents of PCP may help to develop new initiatives for control and prevention of PCP among patients undergoing renal transplant and improve routine PCP prophylaxis.

Molecular diagnosis of Pneumocystis pneumonia in dogs

Pneumocystis pneumonia (PCP) is a life-threatening fungal disease that can occur in dogs. The aim of this study was to provide a preliminary genetic characterisation of Pneumocystis carinii f.sp.'canis' (P. canis) in dogs and thereby develop a reliable molecular protocol to definitively diagnose canine PCP. We investigated P. canis in a variety of lung specimens from dogs with confirmed or strongly suspected PCP (Group 1, n = 16), dogs with non-PCP lower respiratory tract problems (Group 2, n = 65) and dogs not suspected of having PCP or other lower respiratory diseases (Group 3, n = 11). Presence of Pneumocystis DNA was determined by nested PCR of the large and small mitochondrial subunit rRNA loci and by a real-time quantitative polymerase chain reaction (qPCR) assay developed using a new set of primers. Molecular results were correlated with the presence of Pneumocystis morphotypes detected in cytological/histological preparations. Pneumocystis DNA was amplified from 13/16 PCP-suspected dogs (Group 1) and from 4/76 dogs of control Groups 2 and 3 (combined). The latter four dogs were thought to have been colonized by P. canis. Comparison of CT values in 'infected' versus 'colonized' dogs was consistent with this notion, with a distinct difference in molecular burden between groups (CT ≤ 26 versus CT range (26 <CT < 35), respectively). Phylogenetic analyses showed that P. canis is specifically 'canine' associated, being separated from other mammalian Pneumocystis species, thereby confirming the accuracy of qPCR amplicon for Pneumocystis in dogs. Using qPCR, Pneumocystis DNA can be detected in specimens from the respiratory tract and a CT value can be interpreted to distinguish infection versus colonization.