Outcome of HIV-associated Pneumocystis pneumonia in hospitalized patients from 2000 through 2003

Pulmonary tuberculosis complicated by pneumothorax, and acute respiratory distress syndrome (ARDS) in the settings of advanced HIV disease: A case report

Introduction

A large proportion of the global burden of HIV-associated TB occurs in sub-Saharan Africa; including 74% of new cases of TB and 79% of deaths occurs in this area. Spontaneous pneumothorax occurs more frequently in patients with AIDS than the general population with the estimated incidence to be about 2-5% of overall total cases. Tuberculosis ARDS and septic shock are rare but carries extremely poor prognosis.

Case summary

A 27 year old male with advanced HIV disease with very low CD4 count presented to Wolaita Sodo University comprehensive specialized hospital, Ethiopia on July 6, 2023. The patient diagnosed with spontaneous pneumothorax secondary to drug susceptible tuberculosis after positive urine LF-LAM and sputum gene expert. He was intubated after emergency tube thoracostomy, and subsequently treated with anti-TB, corticosteroid, broad-spectrum IV antibiotics and high dose cotrimoxazole. The patient developed ARDS due to possible tuberculosis related septic shock and died of multi-organ failure.

Discussion

Spontaneous pneumothorax in the setting of HIV raises concern for PCP, though in this case it could be secondary to TB. Tuberculosis related ARDS and septic shock are rare complication but carries poor prognosis especially in setting of AHD. We had limited experience and difficulties in the management of patient with persistent pneumothorax with the concomitant ARDS requiring lung protective management, and this part remain the future area of scientific research.

Conclusion

In patients with advanced HIV disease, who present with signs of respiratory failure, the likelihood of spontaneous pneumothorax, TB-ARDS and septic shock should be anticipated in the differential diagnosis and optimal management plan should be designed.

Spatiotemporal Clusters and Trends of Pneumocystis Pneumonia in Korea

This study determined the recent status and trend of Pneumocystis jirovecii pneumonia (PcP) in the non-human immunodeficiency virus (HIV) (non-HIV-PcP) and HIV (HIV-PcP) infected populations using data from the Health Insurance Review & Assessment Service (HIRA) and the Korea Disease Control and Prevention Agency (KDCA). SaTScan and Joinpoint were used for statistical analyses. Non-HIV-PcP cases showed an upward trend during the study period from 2010 to 2021, with the largest number in 2021 (551 cases). The upward trend was similar until 2020 after adjusting for the population. Seoul had the highest number of cases (1,597) in the non-HIV-PcP group, which was the same after adjusting for the population (162 cases/1,000,000). It was followed by Jeju-do (89 cases/1,000,000). The most likely cluster (MLC) for the non-HIV-PCP group was Seoul (Relative Risk (RR)=4.59, Log Likelihood Ratio (LLR)=825.531), followed by Jeju-do (RR=1.59, LLR=5.431). An upward trend was observed among the non-HIV-PcP group in the Jeju-do/Jeollanam-do/Jeollabuk-do/Gyeongsangnam-do/Busan/Daejeon/Daegu/Ulsan joint cluster (29.02%, LLR=11.638, P<0.001) located in the southern part of Korea. Both women and men in the non-HIV groups showed an overall upward trend of PcP during the study period. Men in the 60-69 age group had the highest annual percentage change (APC 41.8) during 2014-2019. In contrast, the HIV groups showed a falling trend of PcP recently. Men in the 60-69 age group had the most decrease (APC -17.6) during 2018-2021. This study provides an analytic basis for health measures and a nationwide epidemiological surveillance system for the management of PcP.

Preliminary Study on the Combination Effect of Clindamycin and Low Dose Trimethoprim-Sulfamethoxazole on Severe Pneumocystis Pneumonia After Renal Transplantation

Objective

Evaluate the effect of the combination of clindamycin with low-dose trimethoprim-sulfamethoxazole (TMP/SMX) regimen on sever Pneumocystis pneumonia (PCP) after renal transplantation.

Method

20 severe PCP patients after renal transplantation were included in this historical-control, retrospective study. A 10 patients were treated with the standard dose of TMP/SMX (T group), the other 10 patients were treated with the combination of clindamycin and low dose TMP/SMX (CT group).

Results

Although there was no significant difference in the hospital survival between the two groups, the CT protocol improved the PaO2/FiO2 ratio more significantly and rapidly after the 6th ICU day (1.51 vs. 0.38, P = 0.014). CT protocol also ameliorated the pulmonary infiltration and the lactate dehydrogenase level more effectively. Moreover, the CT protocol reduced the incidence of pneumomediastinum (0 vs. 50%, P = 0.008), the length of hospital staying (26.5 vs. 39.0 days, P = 0.011) and ICU staying (12.5 vs. 22.5 days, P = 0.008). Furthermore, more thrombocytopenia (9/10 vs. 3/10, P = 0.020) was emerged in the T group than in the CT group. The total adverse reaction rate was much lower in the CT group than in the T group (8/80 vs. 27/80, P < 0.001). Consequently, the dosage of TMP/SMX was reduced in 8 patients, while only 2 patients in the CT group received TMP/SMX decrement (P = 0.023).

Conclusion

The current study proposed that clindamycin combined with low-dose TMP/SMX was more effective and safer the than single use of TMP/SMX for severe PCP patients after renal transplantation (NCT04328688).

Trends in the Epidemiology and Outcomes of Pneumocystis Pneumonia among Human Immunodeficiency Virus (HIV) Hospitalizations

Introduction: Pneumocystis Pneumonia (PCP) is a common opportunistic infection among people living with the human immunodeficiency virus (HIV). This study’s objective was to assess temporal trends in PCP epidemiology among hospitalized patients with HIV/AIDS in the US and to compare data for hospitalizations with HIV with PCP to those without PCP. Methods: The national inpatient sample (NIS) data were analyzed from 2002−2014. The discharge coding identified hospitalized patients with HIV or AIDS and with or without PCP. Results: We identified 3,011,725 hospitalizations with HIV/AIDS during the study period; PCP was present in 5% of the patients with a diagnosis of HIV. The rates of PCP progressively declined from 6.7% in 2002 to 3.5 % in 2014 (p < 0.001). Overall mortality in patients with HIV was 3.3% and was significantly higher in those with PCP than without PCP (9.9% vs. 2.9%; p < 0.001). After adjusting for demographics and other comorbidities, PCP had higher odds of hospital mortality 3.082 (OR 3.082; 95% CI, 3.007 to 3.159; p < 0.001). Conclusion: From 2002 to 2014, the rate of PCP in HIV patients has decreased significantly in the United States but is associated with substantially higher mortality.

Pneumothorax: Classification and Etiology

Pneumothorax is a common problem worldwide. Pneumothorax develops secondary to diverse aetiologies; in many cases, there may be no recognizable lung abnormality. The pathogenetic mechanism(s) causing spontaneous pneumothorax may be related to an interplay between lung-related abnormalities and environmental factors such as smoking. Tobacco smoking is a major risk factor for primary spontaneous pneumothorax; chronic obstructive pulmonary disease is most frequently associated with secondary spontaneous pneumothorax. This review article provides an overview of the historical perspective, epidemiology, classification, and aetiology of pneumothorax. It also aims to highlight current knowledge and understanding of underlying risks and pathophysiological mechanisms in pneumothorax development.

Pneumocystis in metastatic lung cancer, a pragmatic approach in support of prophylaxis

Lung cancer prognosis has improved in the last decade, including in patients with brain metastasis. However, few of these patients who receive corticosteroids have a primary prophylaxis for Pneumocystis jirovecii pneumonia (PJP). We report the case of an 80-year-old man diagnosed with non-small cell lung cancer and concomitant symptomatic brain metastases, treated with 50 mg/day of prednisolone without any prophylaxis, who presented an acute PJP. After 72 hours of unsuccessful treatment of PJP, the patient died. In our review of this case and the existing literature, we emphasise the importance of a wide use of prophylaxis for PJP, especially in advanced lung cancer treated with corticosteroid therapy. We discuss this issue and report current evidence for primary prophylaxis by trimethoprim–sulfamethoxazole.

CD4+ T cell lymphopenia predicts mortality from Pneumocystis pneumonia in kidney transplant patients

BACKGROUND

Pneumocystis jirovecii pneumonia (PcP) remains a life-threatening opportunistic infection after solid organ transplantation, even in the era of Pneumocystis prophylaxis. The association between risk of developing PcP and low CD4⁺ T cell counts has been well established. However, it is unknown whether lymphopenia in the context of post-renal transplant PcP increases the risk of mortality.

METHODS

We carried out a retrospective analysis of a cohort of kidney transplant patients with PcP (n = 49) to determine the risk factors for mortality associated with PcP. We correlated clinical and demographic data with the outcome of the disease. For CD4⁺ T cell counts, we used the Wilcoxon rank sum test for in-hospital mortality and a Cox proportional-hazards regression model for 60-day mortality.

RESULTS

In univariate analyses, high CRP, high neutrophils, CD4⁺ T cell lymphopenia, mechanical ventilation, and high acute kidney injury network stage were associated with in-hospital mortality following presentation with PcP. In a receiver-operator characteristic (ROC) analysis, an optimum cutoff of ≤200 CD4⁺ T cells/µL predicted in-hospital mortality, CD4⁺ T cell lymphopenia remained a risk factor in a Cox regression model.

CONCLUSIONS

Low CD4⁺ T cell count in kidney transplant recipients is a biomarker for disease severity and a risk factor for in-hospital mortality following presentation with PcP.

Critically Ill Patients With HIV: 40 Years Later

The development of combination antiretroviral therapies (cARTs) in the mid-1990s has dramatically modified the clinical presentation of critically ill, HIV-infected patients. Most cART-treated patients aging with controlled HIV replication are currently admitted to the ICU for non-AIDS-related events, mostly bacterial pneumonia and exacerbation of comorbidities, variably affected by chronic HIV infection (COPD, cardiovascular diseases, or solid neoplasms). Today, Pneumocystis jirovecii pneumonia, cerebral toxoplasmosis, TB, and other severe opportunistic infections only occur in patients with unknown viral status, limited access to cART, viral resistance, or compliance issues. Acute respiratory failure, neurological disorders, and sepsis remain the main conditions that lead HIV-infected patients to the ICU, although admissions for liver diseases or acute kidney injury are increasing. Case fatality dropped substantially over the past decades, reaching figures of HIV-uninfected critically ill patients with similar demographic characteristics, comorbidities, and level of organ dysfunctions. Several other facets of critical care management have evolved in this population, including diagnostic procedures, cART management at the acute phase of critical illness, and ethical considerations. The goal of this narrative review was to depict the current evidence and emerging challenges for the management of critically ill, HIV-infected patients, almost 40 years following the onset of the AIDS epidemic.

A Model to Predict In-Hospital Mortality in HIV/AIDS Patients with Pneumocystis Pneumonia in China: The Clinical Practice in Real World

We aimed to develop and validate a predictive model to evaluate in-hospital mortality risk in HIV/AIDS patients with PCP in China. 1001 HIV/AIDS patients with PCP admitted in the Beijing Ditan hospital from August 2009 to January 2018 were included in this study. Multivariate Cox proportional hazard model was used to identify independent risk factors of death, and a predictive model was devised based on risk factors. The overall in-hospital mortality was 17.3%. The patients were randomly assigned into derivation cohort (801cases) and validation cohort (200 cases) in 8:2 ratio, respectively, in which in derivation cohort we found that 7 predictors, including LDH >350U/L, HR>130 times/min, room air PaO₂ <70mmHg, later admission to ICU, Anemia (HGB≤90g/L), CD4<50cells/ul, and development of a pneumothorax, were associated with poor prognosis in HIV/AIDS patients with PCP and were included in the predictive model. The model had excellent discrimination with AUC of 0.904 and 0.921 in derivation and validation cohort, respectively. The predicted scores were divided into two groups to assess the in-hospital mortality risk: low-risk group (0-11 points with mortality with 2.15-12.77%) and high-risk group (12-21 points with mortality with 38.78%-81.63%). The cumulative mortality rate also indicated significant difference between two groups with Kaplan-Meier curve (p<0.001). A predictive model to evaluate mortality in HIV/AIDS patients with PCP was constructed based on routine laboratory and clinical parameters, which may be a simple tool for physicians to assess the prognosis in HIV/AIDS patients with PCP in China.

Pulmonary co-infections by Pneumocystis jirovecii and Aspergillus fumigatus in non-HIV patients: A report of two cases and literature review

Pneumocystis jirovecii is the causative agent of Pneumocystis pneumonia (PcP), a common and often life-threatening opportunistic infection in HIV-infected patients. However, non-HIV, immunocompromised patients are at risk of PcP as well, whereas the mortality appears to be higher among these patients. Pneumocystis co-infections with other microorganisms are less frequent and only sparse reports of combined PcP and invasive pulmonary fungal infections exist in the literature, especially in the non-HIV patients. Two cases of pulmonary co-infections by P. jirovecii and Aspergillus fumigatus are presented. Both patients were non-HIV infected, the first one was suffering from crescentic IgA nephropathy under immunosuppressive treatment and the second from resistant non-Hodgkin lymphoma under chemotherapy. Both patients were treated with intravenous trimethoprim/sulphamethoxazole (TMP/SMX) combined with voriconazole. The first patient showed gradual clinical improvement while the outcome for the second patient was unfavourable. In addition, a literature review of the previous published cases of co-infection by P. jirovecii and other fungi in non-HIV patients was performed. Our target was to provide comprehensive information on this kind of infections, highlighting the importance of clinical suspicion.

Neither classical nor alternative macrophage activation is required for Pneumocystis clearance during immune reconstitution inflammatory syndrome

Pneumocystis is a respiratory fungal pathogen that causes pneumonia (Pneumocystis pneumonia [PcP]) in immunocompromised patients. Alveolar macrophages are critical effectors for CD4(+) T cell-dependent clearance of Pneumocystis, and previous studies found that alternative macrophage activation accelerates fungal clearance during PcP-related immune reconstitution inflammatory syndrome (IRIS). However, the requirement for either classically or alternatively activated macrophages for Pneumocystis clearance has not been determined. Therefore, RAG2(-/-) mice lacking either the interferon gamma (IFN-γ) receptor (IFN-γR) or interleukin 4 receptor alpha (IL-4Rα) were infected with Pneumocystis. These mice were then immune reconstituted with wild-type lymphocytes to preserve the normal T helper response while preventing downstream effects of Th1 or Th2 effector cytokines on macrophage polarization. As expected, RAG2(-/-) mice developed severe disease but effectively cleared Pneumocystis and resolved IRIS. Neither RAG/IFN-γR(-/-) nor RAG/IL-4Rα(-/-) mice displayed impaired Pneumocystis clearance. However, RAG/IFN-γR(-/-) mice developed a dysregulated immune response, with exacerbated IRIS and greater pulmonary function deficits than those in RAG2 and RAG/IL-4Rα(-/-) mice. RAG/IFN-γR(-/-) mice had elevated numbers of lung CD4(+) T cells, neutrophils, eosinophils, and NK cells but severely depressed numbers of lung CD8(+) T suppressor cells. Impaired lung CD8(+) T cell responses in RAG/IFN-γR(-/-) mice were associated with elevated lung IFN-γ levels, and neutralization of IFN-γ restored the CD8 response. These data demonstrate that restricting the ability of macrophages to polarize in response to Th1 or Th2 cytokines does not impair Pneumocystis clearance. However, a cell type-specific IFN-γ/IFN-γR-dependent mechanism regulates CD8(+) T suppressor cell recruitment, limits immunopathogenesis, preserves lung function, and enhances the resolution of PcP-related IRIS.

Treatment of Pneumocystis pneumonia with intermediate-dose and step-down to low-dose trimethoprim-sulfamethoxazole: lessons from an observational cohort study

Background

The recommended treatment of Pneumocystis jirovecii pneumonia (PCP) is high-dose trimethoprim–sulfamethoxazole (TMP–SMX) in an equivalent of TMP 15–20 mg/kg/day and SMX 75–100 mg/kg/day for 2 or 3 weeks. High rates of adverse events are reported with this dose, which raises the question if lower doses are possible.

Methods

All adult patients diagnosed with PCP in various immune dysfunctions and treated with TMP–SMX between January 1, 2003 and July 1, 2013 in a tertiary university hospital were included. Per institutional protocol, patients initiated treatment on intermediate-dose TMP–SMX (TMP 10–15 mg/kg/day) and could be stepped down to low-dose TMP–SMX (TMP 4–6 mg/kg/day) during treatment. Clinical variables at presentation, relapse rate and mortality rates were compared between intermediate- and step-down treatment groups by uni- and multivariate analyses.

Results

A total of 104 patients were included. Twenty-four patients (23 %) were switched to low-dose TMP–SMX after a median of 4.5 days (IQR 2.8–7.0 days). One relapse (4 %) occurred in the step-down group versus none in the intermediate-dose group. The overall 30-day mortality was 13 %. There was 1 death in the step-down group (4 %) compared to 13 deaths (16 %) in the intermediate-dose group.

Conclusions

We observed high cure rates of PCP by treatment with intermediate-dose TMP–SMX. In addition, a step-down strategy to low-dose TMP–SMX during treatment in selected patients appears to be safe and does not compromise the outcome of treatment.

Epidemiology and long-term survival in HIV-infected patients with Pneumocystis jirovecii pneumonia in the HAART era: experience in a university hospital and review of the literature

As highly active antiretroviral treatment (HAART) is widely available, the incidence of Pneumocystis jirovecii pneumonia (PJP) has decreased significantly but still represents a significant cause of morbidity and mortality in developed countries. We analyzed all the cases with PJP in human immunodeficiency virus (HIV)-infected patients from 2000 to 2013 in a university hospital in Barcelona, Spain, and conducted a systematic literature review to evaluate data regarding incidence, mortality, and long-term survival after PJP in developed settings. One hundred thirty-six episodes of PJP were analyzed. During the study period, the incidence decreased significantly (from 13.4 cases/1000 patients-year to 3.3 cases/1000 patients-year, P < 0.001). Oppositely, median age of the patients increased from 34 years in 2000 to 45 in 2013 (P = 0.024). PJP preceded HIV diagnosis in nearly 50% of the cases. Fifteen (11%) patients died during the PJP episode. The main risk factor for in-hospital mortality in our cohort was age >50 years (odds ratio 4.96, 95% confidence interval [CI] 1.45-15.14). Patients who survived were followed-up during a mean time of 44 months. Overall 5-year survival of patients after hospital discharge was 73%. Survival likelihood was 54% higher (88% [95% CI 81-96]) among HAART-adherent patients. Mean age and the proportion of patients with unknown HIV infection at the time of PJP diagnosis have increased in developed countries in the HAART era. Although the incidence has decreased, in-hospital mortality remains stable in this setting. Long-term survival is very high among HAART-adherent patients.

Classical versus alternative macrophage activation: the Ying and the Yang in host defense against pulmonary fungal infections

Macrophages are innate immune cells that possess unique abilities to polarize toward different phenotypes. Classically activated macrophages are known to have major roles in host defense against various microbial pathogens, including fungi, while alternatively activated macrophages are instrumental in immune-regulation and wound healing. Macrophages in the lungs are often the first responders to pulmonary fungal pathogens, and the macrophage polarization state has the potential to be a deciding factor in disease progression or resolution. This review discusses the distinct macrophage polarization states and their roles during pulmonary fungal infection. We focus primarily on Cryptococcus neoformans and Pneumocystis model systems as disease resolution of these two opportunistic fungal pathogens is linked to classically or alternatively activated macrophages, respectively. Further research considering macrophage polarization states that result in anti-fungal activity has the potential to provide a novel approach for the treatment of fungal infections.

Critical importance of long-term adherence to care in HIV infected patients in the cART era: new insights from Pneumocystis jirovecii pneumonia cases over 2004-2011 in the FHDH-ANRS CO4 cohort

OBJECTIVE

To describe characteristics and outcomes of HIV-infected patients with Pneumocystis jirovecii pneumonia (PCP) over 2004-2011 in France, in particular in those previously enrolled (PE) in the French Hospital Database on HIV (FHDH).

METHODS

PE patients with an incident PCP were compared with patients with an inaugural PCP revealing HIV infection (reference). Adequate adherence to care was defined as a CD4 measurement at least every 6 months. Immune reconstitution (CD4≥200/mm3) and risk of death were studied using Kaplan-Meier estimates and multivariable Cox proportional hazards models.

RESULTS

In a context of a decreasing incidence of PCP, 1259 HIV-infected patients had a PCP diagnosis, and 593 (47%) were PE patients of whom 161 (27%) have had a prior history of AIDS-defining clinical illness (prior ADI). Median time since enrolment was 8 years for PE patients; 74% had received cART. Median proportion of time with adequate adherence to care was 85% (IQR, 66-96) for all FHDH enrollees, but only 45% (IQR, 1-81) for PE patients during the 2 years before PCP. Median CD4 cell count (38/mm3) and HIV viral load (5.2 log10 copies/ml) at PCP diagnosis did not differ between PE patients and the reference group. Three year mortality rate of 25% was observed for PE prior ADI group, higher than in PE non-prior ADI group (8%) and the reference group (9%) (p<0.0001). In the PE prior ADI group, poor prognosis remained even after adjustment for virological control and immune reconstitution (HR, 2.4 [95%CI, 1.5-3.7]).

CONCLUSION

Almost 50% of PCP diagnoses in HIV-infected patients occurred presently in patients already in care, mainly with a previous cART prescription but with waning adherence to care. Having repeated ADI is contributing to the risk of death beyond its impact on immune reconstitution and viral suppression: special efforts must be undertaken to maintain those patients in care.

[Pneumocystis jiroveci pneumonia: Clinical characteristics and mortality risk factors in an Intensive Care Unit]

OBJECTIVE

To describe the epidemiological characteristics of the population with Pneumocystis jiroveci (P. jiroveci) pneumonia, analyzing risk factors associated with the disease, predisposing factors for admission to an intensive care unit (ICU), and prognostic factors of mortality.

DESIGN AND PATIENTS

A retrospective observational study was carried out, involving a cohort of patients consecutively admitted to a hospital in Spain from 1 January 2007 to 31 December 2011, with a final diagnosis of P. jiroveci pneumonia.

SETTING

The ICU and hospitalization service of Hospital del Mar, Barcelona (Spain).

RESULTS

We included 36 patients with pneumonia due to P. jiroveci. Of these subjects, 16 required ICU admission (44.4%). The average age of the patients was 41.3 ± 12 years, and 23 were men (63.9%). A total of 86.1% had a history of human immunodeficiency virus (HIV) infection, and the remaining 13.9% presented immune-based disease subjected to immunosuppressive therapy. Risk factors associated to hospital mortality were age (51.8 vs. 37.3 years, P=.002), a higher APACHE score upon admission (17 vs. 13 points, P=.009), the need for invasive mechanical ventilation (27.8% vs. 11.1%, P=.000), requirement of vasoactive drugs (25.0% vs. 11.1%, P=.000), fungal coinfection (22.2% vs. 11.1%, P=.001), pneumothorax (16.7% vs. 83.3%, P=.000) and admission to the ICU (27.8% vs. 72.2% P=.000).

CONCLUSIONS

The high requirement of mechanical ventilation and vasoactive drugs associated with fungal coinfection and pneumothorax in patients admitted to the ICU remain as risk factors associated with mortality in patients with P. jiroveci pneumonia.

Pneumocystis jirovecii genotype associated with increased death rate of HIV-infected patients with pneumonia

Comorbidities might predict presence of specific fungal genotypes.

STAT4-dependent and -independent Th2 responses correlate with protective immunity against lung infection with Pneumocystis murina

Although it is clear that the loss of CD4(+) T cells is a predisposing factor for the development of Pneumocystis pneumonia, specific Th mechanisms mediating protection are not well understood. Th1, Th2, and Th17 responses have each been implicated in protective responses during infection. As STAT4 may promote Th1 and Th17 development, yet antagonize Th2 development, we investigated its role in Pneumocystis murina host defense. STAT4 was required for Th1 and, unexpectedly, Th2 responses in the lungs of C57BL/6 (BL/6) and BALB/c mice 14 d postchallenge, but only BALB/c Stat4(-/-) mice demonstrated susceptibility to P. murina lung infection. BL/6 Stat4(-/-), but not BALB/c Stat4(-/-), mice maintained an enhanced alternatively activated (M2) macrophage signature in the lungs, which we have previously reported to be associated with enhanced P. murina clearance. In addition, anti-P. murina class-switched Abs were increased in BL/6 Stat4(-/-) mice, but not BALB/c Stat4(-/-) mice. Supporting our experimental observations, plasma from HIV-infected individuals colonized with Pneumocystis jirovecii contained significantly lower levels of the Th2 cytokines IL-4, IL-5, and IL-13 compared with HIV-infected individuals who were not colonized. Collectively, our data suggest that robust local and systemic Th2-mediated responses are critical for immunity to Pneumocystis.

Pneumocystis pneumonia associated with human immunodeficiency virus

Pneumocystis pneumonia (PCP) is caused by the yeastlike fungus Pneumocystis. Despite the widespread availability of specific anti-Pneumocystis prophylaxis and of combination antiretroviral therapy (ART), PCP remains a common AIDS-defining presentation. PCP is increasingly recognized among persons living in Africa. Pneumocystis cannot be cultured and bronchoalveolar lavage is the gold standard diagnostic test to diagnose PCP. Use of adjunctive biomarkers for diagnosis requires further evaluation. Trimethoprim-sulfamethoxazole remains the preferred first-line treatment regimen. In the era of ART, mortality from PCP is approximately 10% to 12%. The optimal time to start ART in a patient with PCP remains uncertain.

Pneumocystis jiroveci pneumonia in immunocompromised patients: delayed diagnosis and poor outcomes in non-HIV-infected individuals

BACKGROUND

Pneumocystis jiroveci pneumonia (PJP) is a life-threatening disease in immunocompromised patients. Improved knowledge about the varied characteristics and management in different populations may guide treatment.

METHODS

We evaluated the clinical characteristics, management, and outcomes of patients with PJP diagnosed by nested polymerase chain reaction at a medical center in southern Taiwan from 2008 to 2011. The risk factors of mortality among non-human immunodeficiency virus (HIV)-infected patients were analyzed.

RESULTS

During the study period, there were 43 cases of PJP, and the common underlying diseases were HIV infection (23 patients, median CD4 count: 19/μl) and malignancy. The HIV-infected patients had a younger age (36.9 ± 13.7 vs. 50.2 ± 16.2 years, p = 0.006), a lower body mass index (19.9 ± 2.3 vs. 22.0 ± 3.7 kg/m(2), p = 0.035), a longer duration of symptoms before admission (24 ± 29 vs. 7 ± 15 days, p = 0.035), and a lower pneumonia severity index (56 ± 25 vs. 99 ± 35, p < 0.001) than non-HIV-infected patients. A delay between admission and starting antimicrobial therapy for PJP (10 ± 10 days vs. 1 ± 3 days, p = 0.004) and a high crude mortality (12/20, 60% vs. 2/23, 9%, p = 0.001) were noted in non-HIV-infected patients. In the univariate analysis, the risk factors for mortality were a low lymphocyte count (p < 0.05) and shock during hospitalization (p = 0.004).

CONCLUSION

A delay in the initiation of antimicrobial therapy for PJP and severe pneumonia were more common in the non-HIV-infected patients and were most likely related to the poor prognosis. The utilization of sensitive diagnostic tools to facilitate early diagnosis and treatment may improve the clinical outcomes of non-HIV-infected patients with PJP.

Colonization by Pneumocystis jirovecii and its role in disease

Although the incidence of Pneumocystis pneumonia (PCP) has decreased since the introduction of combination antiretroviral therapy, it remains an important cause of disease in both HIV-infected and non-HIV-infected immunosuppressed populations. The epidemiology of PCP has shifted over the course of the HIV epidemic both from changes in HIV and PCP treatment and prevention and from changes in critical care medicine. Although less common in non-HIV-infected immunosuppressed patients, PCP is now more frequently seen due to the increasing numbers of organ transplants and development of novel immunotherapies. New diagnostic and treatment modalities are under investigation. The immune response is critical in preventing this disease but also results in lung damage, and future work may offer potential areas for vaccine development or immunomodulatory therapy. Colonization with Pneumocystis is an area of increasing clinical and research interest and may be important in development of lung diseases such as chronic obstructive pulmonary disease. In this review, we discuss current clinical and research topics in the study of Pneumocystis and highlight areas for future research.

Use of the relationship between absolute lymphocyte count and CD4 count to improve earlier consideration of pneumocystis pneumonia in HIV-positive emergency department patients with pneumonia

BACKGROUND

The ability to accurately assess the level of immunosuppression in HIV+ patients in the emergency department (ED) is often limited and can affect management of these patients.

OBJECTIVE

To evaluate the relationship between the absolute lymphocyte count (ALC) and CD4 count in HIV patients admitted through the ED with pneumonia and how utilization of this relationship may affect early consideration and evaluation of Pneumocystis jiroveci pneumonia (PCP).

METHODS

Retrospective multicenter 5-year study of HIV+ patients with an ICD-9 diagnosis of pneumonia. Included patients had an ALC measured on ED presentation and a CD4 count measured in < 24 h. A receiver operator curve (ROC), decision plot analysis, and McNemar test of proportions were used to characterize the relationship between study variables.

RESULTS

Six hundred eighty six patients were enrolled, 23.2% (95% confidence interval [CI] 20.2-26.1) were diagnosed with PCP. The geometric mean CD4 count and ALC were 81 and 1089, respectively. The correlation between ALC and CD4 was r = 0.60 (95% CI 0.55-65, p < 0.01). The ROC was 0.78 (0.75-0.82). An ALC < 1700 cells/mm(3) had a sensitivity of 84% (95% CI 80-87) and specificity of 55% (95% CI 48-70) for a CD4 < 200 cells/mm(3). An ALC threshold of 1700 cells/mm(3) would have identified 86% of patients with PCP but falsely identified 2.5 patients without PCP for every one accurately identified.

CONCLUSION

The ALC threshold of 1700 cells/mm(3) retains significant discriminatory value and would moderately improve identification of patients with a CD4 < 200 cells/mm(3) but is not likely to be reliable as the sole method of early recognition and evaluation of PCP.

A prognostic scoring tool for identification of patients at high and low risk of death from HIV-associated Pneumocystis jirovecii pneumonia

A prognostic scoring tool (PST) was created to aid prediction of outcome from HIV-associated Pneumocystis jirovecii pneumonia (PCP) using data obtained from 577 episodes of PCP among 540 patients presenting to a specialist HIV treatment centre in London, UK. It used risk factors identifiable at/soon after hospitalization, previously identified as being associated with mortality: repeat episode of PCP, patient's age, haemoglobin (Hb) and oxygen partial pressure (PaO2) on admission, presence of medical co-morbidity (Comorb) and of pulmonary Kaposi sarcoma (PKS). The derived PST was 25.5+(age in years/10) + 2 (if a repeat episode of PCP) + 3 (if Comorb present) + 4 (if PKS detected) – PaO2 (kPa) – Hb (g/dL), and produced scores that ranged between 0 and 19. Patients were divided into five groups according to their prognostic score: 0-3.9 = group 1 (0% mortality), 4-7.9 = group 2 (3% mortality), 8-10.9 = group 3 (9% mortality), 11-14.9 = group 4 (29% mortality) and ≥15 = group 5 (52% mortality). This PST facilitates rapid identification of patients early in their hospitalization who have mild or severe HIV-associated PCP and who are at high and low risk of in-hospital death from PCP. The PST may aid assessment of severity of illness and in directing treatment strategies, but requires validation in patient cohorts from other healthcare institutions.

Critical illness in HIV-infected patients in the era of combination antiretroviral therapy

As HIV-infected persons on combination antiretroviral therapy (ART) are living longer and rates of opportunistic infections have declined, serious non-AIDS-related diseases account for an increasing proportion of deaths. Consistent with these changes, non-AIDS-related illnesses account for the majority of ICU admissions in more recent studies, in contrast to earlier eras of the AIDS epidemic. Although mortality after ICU admission has improved significantly since the earliest HIV era, it remains substantial. In this article, we discuss the current state of knowledge regarding the impact of ART on incidence, etiology, and outcomes of critical illness among HIV-infected patients. In addition, we consider issues related to administration of ART in the ICU and identify important areas of future research.

HIV-associated Pneumocystis pneumonia

During the past 30 years, major advances have been made in our understanding of HIV/AIDS and Pneumocystis pneumonia (PCP), but significant gaps remain. Pneumocystis is classified as a fungus and is host-species specific, but an understanding of its reservoir, mode of transmission, and pathogenesis is incomplete. PCP remains a frequent AIDS-defining diagnosis and is a frequent opportunistic pneumonia in the United States and in Europe, but comparable epidemiologic data from other areas of the world that are burdened with HIV/AIDS are limited. Pneumocystis cannot be cultured, and bronchoscopy with bronchoalveolar lavage is the gold standard procedure to diagnose PCP, but noninvasive diagnostic tests and biomarkers show promise that must be validated. Trimethoprim-sulfamethoxazole is the recommended first-line treatment and prophylaxis regimen, but putative trimethoprim-sulfamethoxazole drug resistance is an emerging concern. The International HIV-associated Opportunistic Pneumonias (IHOP) study was established to address these knowledge gaps. This review describes recent advances in the pathogenesis, epidemiology, diagnosis, and management of HIV-associated PCP and ongoing areas of clinical and translational research that are part of the IHOP study and the Longitudinal Studies of HIV-associated Lung Infections and Complications (Lung HIV).

The changing epidemiology of HIV-infected patients in the intensive care unit

With the introduction of highly active antiretroviral therapy (HAART), HIV has become a chronic disease. As HIV-infected patients are aging, they are at increased risk for comorbid diseases. These non-AIDS related diseases account for a growing proportion of intensive care unit (ICU) admissions in HIV-infected patients in recent studies. HIV-infected patients still present to the ICU with HIV-related conditions such as Pneumocystis jirovecii pneumonia (PCP), but these conditions are becoming less common. Respiratory failure remains the most common indication for ICU admission. Immune reconstitution inflammatory response syndrome and toxicities related to HAART may also result in ICU admission. While ICU survival has improved since the earliest era of the HIV epidemic, hospital mortality for HIV-infected patients admitted to the ICU remains around 30%. Risk factors for ICU mortality include poor functional status, weight loss, more than one year between HIV diagnosis and ICU admission, lower serum albumin, higher severity of illness, need for mechanical ventilation, and respiratory failure-particularly if due to PCP and accompanied by pneumothorax. The impact of HAART on ICU outcomes is unclear. HAART administration in the ICU can be challenging due to limited delivery routes, concern for viral resistance and medication toxicities. There are no data to determine the safety or efficacy of HAART initiation in the ICU. Future studies are needed to address the role of age, associated comorbidities and impact of HAART on outcomes of HIV-infected patients admitted to the ICU.

Clinical and translational research in pneumocystis and pneumocystis pneumonia

Pneumocystis pneumonia (PcP) remains a significant cause of morbidity and mortality in immunocompromised persons, especially those with human immunodeficiency virus (HIV) infection. Pneumocystis colonization is described increasingly in a wide range of immunocompromised and immunocompetent populations and associations between Pneumocystis colonization and significant pulmonary diseases such as chronic obstructive pulmonary disease (COPD) have emerged. This mini-review summarizes recent advances in our clinical understanding of Pneumocystis and PcP, describes ongoing areas of clinical and translational research, and offers recommendations for future clinical research from researchers participating in the "First centenary of the Pneumocystis discovery".

Seasonal variation in mortality of Pneumocystis jirovecii pneumonia in HIV-infected patients

A seasonal variation in the presentation of Pneumocystis jirovecii pneumonia (PCP) has been reported and a previous study from this centre noted a seasonal variation in mortality rates. This study examined seasonal influences (including climatic factors) within-host factors (clinical and laboratory-derived variables), the infectious burden of P. jirovecii in bronchoalveolar lavage (BAL) fluid, the presence of dihydropteroate synthase (DHPS) mutations in P. jirovecii, variations in knowledge and skills of junior medical staff, and mortality in 547 episodes of PCP occurring in 494 HIV-infected patients. The overall mortality rate was 13.5%. There was a seasonal variation in mortality: highest in autumn (21.2%) and lowest in spring (9.7%), P = 0.047. After adjustment was made for prognostic factors previously identified as being associated with mortality (increasing patient age, second/third episode of PCP, low haemoglobin, low PaO(2), presence of medical co-morbidity and pulmonary Kaposi sarcoma), there was no seasonal association with mortality, P = 0.249. The quantity of P. jirovecii DNA in BAL fluid showed no evidence of seasonal variation, P = 0.67; DHPS mutations were identified with equal frequency in each season and the mortality rate for February and August (when junior medical staff arrive in new posts) was 16.7%, only slightly greater than for other months (13.0%).

IL-33 and M2a alveolar macrophages promote lung defense against the atypical fungal pathogen Pneumocystis murina

We have recently reported that mice deficient in the myeloid Src-family tyrosine kinases Hck, Fgr, and Lyn (Src triple knockout [TKO]) had augmented innate lung clearance of Pneumocystis murina that correlated with a higher ability of alveolar macrophages (AMs) from these mice to kill P. murina. In this article, we show that despite possessing enhanced killing, AMs from naive Src TKO mice did not demonstrate enhanced inflammatory responses to P. murina. We subsequently discovered that both AMs and lungs from P. murina-infected Src TKO mice expressed significantly greater levels of the M2a markers RELM-α and Arg1, and the M2a-associated chemokines CCL17 and CCL22 than did wild-type mice. IL-4 and IL-13, the primary cytokines that promote M2a polarization, were not differentially produced in the lungs between wild-type and Src TKO mice. P. murina infection in Src TKO mice resulted in enhanced lung production of the novel IL-1 family cytokine IL-33. Immunohistochemical analysis of IL-33 in lung tissue revealed localization predominantly in the nucleus of alveolar epithelial cells. We further demonstrate that experimental polarization of naive AMs to M2a resulted in more efficient killing of P. murina compared with untreated AMs, which was further enhanced by the addition of IL-33. Administration of IL-33 to C57BL/6 mice increased lung RELM-α and CCL17 levels, and enhanced clearance of P. murina, despite having no effect on the cellular composition of the lungs. Collectively, these results indicate that M2a AMs are potent effector cells against P. murina. Furthermore, enhancing M2a polarization may be an adjunctive therapy for the treatment of Pneumocystis.

Pneumocystis jirovecii multilocus gene sequencing: findings and implications

Pneumocystis jirovecii pneumonia (PcP) remains a major cause of respiratory illness among immunocompromised patients, especially patients infected with HIV, but it has also been isolated from immunocompetent persons. This article discusses the application of multilocus genotyping analysis to the study of the genetic diversity of P. jirovecii and its epidemiological and clinical parameters, and the important concepts achieved to date with these approaches. The multilocus typing studies performed until now have shown that there is an important genetic diversity of stable and ubiquitous P. jirovecii genotypes; infection with P. jirovecii is not necessarily clonal, recombination between some P. jirovecii multilocus genotypes has been suggested. P. jirovecii-specific multilocus genotypes can be associated with severity of PcP. Patients infected with P. jirovecii, regardless of the form of infection they present with, are part of a common human reservoir for future infections. The CYB, DHFR, DHPS, mtLSU rRNA, SOD and the ITS loci are suitable genetic targets to be used in further epidemiological studies focused on the identification and characterization of P. jirovecii haplotypes correlated with drug resistance and PcP outcome.

Severity and outcomes of Pneumocystis pneumonia in patients newly diagnosed with HIV infection: an observational cohort study

It is unclear whether patients who are unaware of their HIV infection have different severity or outcomes of Pneumocystis pneumonia (PCP) compared to patients who have been previously diagnosed with HIV. In this retrospective observational cohort study of consecutive HIV-infected patients with microscopically diagnosed PCP at San Francisco General Hospital between 1997 and 2006, 121 of 522 patients (23%) were unaware of their HIV infection prior to their diagnosis of PCP. The proportion of patients with concurrently diagnosed HIV and PCP each year remained unchanged during the study period. Patients with newly diagnosed HIV had a significantly higher alveolar-arterial oxygen gradient at presentation (median 51 vs 45 mm Hg, p =0.03), but there were no differences in mortality, frequency of mechanical ventilation, or admission to intensive care compared to patients with previously diagnosed HIV infection. In multivariate analysis, patients who reported a sexual risk factor for HIV infection were more likely to be newly diagnosed with HIV than patients who reported injection drug use as their only HIV risk factor (odds ratio = 3.14, 95% CI 1.59-6.18, p=0.001). This study demonstrates a continued need for HIV education and earlier HIV testing, particularly in patients with high-risk sexual behavior.

Echinocandin treatment of pneumocystis pneumonia in rodent models depletes cysts leaving trophic burdens that cannot transmit the infection

Fungi in the genus Pneumocystis cause pneumonia (PCP) in hosts with debilitated immune systems and are emerging as co-morbidity factors associated with chronic diseases such as COPD. Limited therapeutic choices and poor understanding of the life cycle are a result of the inability of these fungi to grow outside the mammalian lung. Within the alveolar lumen, Pneumocystis spp., appear to have a bi-phasic life cycle consisting of an asexual phase characterized by binary fission of trophic forms and a sexual cycle resulting in formation of cysts, but the life cycle stage that transmits the infection is not known. The cysts, but not the trophic forms, express β -1,3-D-glucan synthetase and contain abundant β -1,3-D-glucan. Here we show that therapeutic and prophylactic treatment of PCP with echinocandins, compounds which inhibit the synthesis of β -1,3-D-glucan, depleted cysts in rodent models of PCP, while sparing the trophic forms which remained in significant numbers. Survival was enhanced in the echincandin treated mice, likely due to the decreased β -1,3-D-glucan content in the lungs of treated mice and rats which coincided with reductions of cyst numbers, and dramatic remodeling of organism morphology. Strong evidence for the cyst as the agent of transmission was provided by the failure of anidulafungin-treated mice to transmit the infection. We show for the first time that withdrawal of anidulafungin treatment with continued immunosuppression permitted the repopulation of cyst forms. Treatment of PCP with an echinocandin alone will not likely result in eradication of infection and cessation of echinocandin treatment while the patient remains immunosuppressed could result in relapse. Importantly, the echinocandins provide novel and powerful chemical tools to probe the still poorly understood bi-phasic life cycle of this genus of fungal pathogens.

Differences in the clinical characteristics of Pneumocystis jirovecii pneumonia in immunocompromized patients with and without HIV infection

BACKGROUND AND OBJECTIVE

The incidence of Pneumocystis jirovecii pneumonia (PCP) in patients with predisposing immunodeficiencies other than AIDS is growing. Knowing the different characteristics and outcomes of PCP according to HIV status would help physicians manage and treat patients with PCP.

METHODS

The medical charts of all patients with a proven first episode of PCP, diagnosed between 1997 and 2007 were retrospectively reviewed, and clinical and laboratory data abstracted.

RESULTS

Of the 35 patients with PCP, 18 were HIV-positive and 17 were HIV-negative with other immunosuppressive conditions. HIV-negative patients were significantly older than HIV-positive patients. The WCC (10 952 +/- 5669 vs 9750 +/- 3133/microL; P = 0.015), neutrophil counts (9631 +/- 5421 vs 5680 +/- 2628/microL; P = 0.01) and CD4+ lymphocyte counts (329 +/- 502 vs 47 +/- 50/microL; P < 0.001) were significantly higher in HIV-negative patients. Six of the 17 HIV-negative patients had a CD4+ lymphocyte count >300/microL. Serum IgG levels were lower in HIV-negative patients (943 +/- 379 vs 1635 +/- 657 mg/dL; P = 0.017). Mortality was higher in HIV-negative (52.9%) than in HIV-positive patients (0%). On univariate analysis, risk factors for mortality from PCP were the presence of underlying pulmonary disease (odds ratio 4.000, 95% CI: 1.501-10.658) and HIV-negative status (odds ratio 2.125, 95% CI: 1.283-3.518).

CONCLUSIONS

The characteristics and outcomes of PCP differ significantly depending on HIV status. The existence of underlying pulmonary diseases may be associated with the prognosis of HIV-negative patients with PCP.

Predicting mortality from HIV-associated Pneumocystis pneumonia at illness presentation: an observational cohort study

BACKGROUND

Although the use of antiretroviral therapy has led to dramatic declines in AIDS-associated mortality, Pneumocystis pneumonia (PCP) remains a leading cause of death in HIV-infected patients.

OBJECTIVES

To measure mortality, identify predictors of mortality at time of illness presentation and derive a PCP mortality prediction rule that stratifies patients by risk for mortality.

METHODS

An observational cohort study with case note review of all HIV-infected persons with a laboratory diagnosis of PCP at San Francisco General Hospital from 1997 to 2006.

RESULTS

451 patients were diagnosed with PCP on 524 occasions. In-hospital mortality was 10.3%. Multivariate analysis identified five significant predictors of mortality: age (adjusted odds ratio (AOR) per 10-year increase, 1.69; 95% CI 1.08 to 2.65; p = 0.02); recent injection drug use (AOR 2.86; 95% CI 1.28 to 6.42; p = 0.01); total bilirubin >0.6 mg/dl (AOR 2.59; 95% CI 1.19 to 5.62; p = 0.02); serum albumin <3 g/dl (AOR 3.63; 95% CI 1.72-7.66; p = 0.001); and alveolar-arterial oxygen gradient >or=50 mm Hg (AOR 3.02; 95% CI 1.41 to 6.47; p = 0.004). Using these five predictors, a six-point PCP mortality prediction rule was derived that stratifies patients according to increasing risk of mortality: score 0-1, 4%; score 2-3, 12%; score 4-5, 48%.

CONCLUSIONS

The PCP mortality prediction rule stratifies patients by mortality risk at the time of illness presentation and should be validated as a clinical tool.

Pneumocystis pneumonia: current concepts in pathogenesis, diagnosis, and treatment

Pneumocystis pneumonia (PCP) is an infection of the lungs caused by the opportunistic fungal genus Pneumocystis. In humans, PCP is a serious and potentially life-threatening infection occurring in immunocompromised individuals, particularly those who have AIDS, or following immune suppression from malignancy, organ transplantation, or therapies for inflammatory diseases. Several recent studies have contributed to understanding of the biology and pathogenesis of the organism yielding new diagnostic approaches and therapeutic targets. Although trimethoprim-sulfamethoxazole remains the mainstay of prophylaxis and treatment, ongoing concerns for emerging Pneumocystis resistance supports the continuing investigation for novel therapeutic agents.