High prevalence of Pneumocystis jiroveci colonization among young HIV-infected patients

Diagnosing Pneumocystis jirovecii pneumonia: A review of current methods and novel approaches

Pneumocystis jirovecii can cause life-threatening pneumonia in immunocompromised patients. Traditional diagnostic testing has relied on staining and direct visualization of the life-forms in bronchoalveolar lavage fluid. This method has proven insensitive, and invasive procedures may be needed to obtain adequate samples. Molecular methods of detection such as polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), and antibody-antigen assays have been developed in an effort to solve these problems. These techniques are very sensitive and have the potential to detect Pneumocystis life-forms in noninvasive samples such as sputum, oral washes, nasopharyngeal aspirates, and serum. This review evaluates 100 studies that compare use of various diagnostic tests for Pneumocystis jirovecii pneumonia (PCP) in patient samples. Novel diagnostic methods have been widely used in the research setting but have faced barriers to clinical implementation including: interpretation of low fungal burdens, standardization of techniques, integration into resource-poor settings, poor understanding of the impact of host factors, geographic variations in the organism, heterogeneity of studies, and limited clinician recognition of PCP. Addressing these barriers will require identification of phenotypes that progress to PCP and diagnostic cut-offs for colonization, generation of life-form specific markers, comparison of commercial PCR assays, investigation of cost-effective point of care options, evaluation of host factors such as HIV status that may impact diagnosis, and identification of markers of genetic diversity that may be useful in diagnostic panels. Performing high-quality studies and educating physicians will be crucial to improve the rates of diagnosis of PCP and ultimately to improve patient outcomes.

Pneumocystis pneumonia in the twenty-first century: HIV-infected versus HIV-uninfected patients

Introduction: Pneumocystis pneumonia (PcP) has classically been described as a serious complication in patients infected with the human immunodeficiency virus (HIV). However, the emerging number of conditions associated with immunosuppression has led to its appearance in other patient populations. Areas covered: This article reviews the most recent publications on PcP in the HIV-infected and HIV-uninfected population, focusing on epidemiology, diagnostic, therapy and prevention. The data discussed here were mainly obtained from a non-systematic review using Medline and references from relevant articles including randomized clinical trials, meta-analyses, observational studies and clinical reviews. Expert opinion: The growing incidence of Pneumocystis infection in the HIV-uninfected population suggests the need for new global epidemiological studies in order to identify the true scale of the disease in this population. These data would allow us to improve diagnosis, therapeutic strategies, and clinical management. It is very important that both patients and physicians realize that HIV-uninfected patients are at risk of PcP and that rapid diagnosis and early initiation of treatment are associated with better prognosis. Currently, in-hospital mortality rates are very high: 15% for HIV-infected patients and 50% in some HIV-uninfected patients. Therefore, adequate preventive measures should be implemented to avoid the high mortality rates seen in recent decades.

Development and Characterization of Dapsone Cocrystal Prepared by Scalable Production Methods

In this study, the formation of caffeine/dapsone (CAF/DAP) cocrystals by scalable production methods, such as liquid-assisted grinding (LAG) and spray drying, was investigated in the context of the potential use of processed cocrystal powder for pulmonary delivery. A CAF/DAP cocrystal (1:1 M ratio) was successfully prepared by slow evaporation from both acetone and ethyl acetate. Acetone, ethyl acetate, and ethanol were all successfully used to prepare cocrystals by LAG and spray drying. The powders obtained were characterized by X-ray diffractometry (XRD), differential scanning calorimetry (DSC), thermogravimetry (TGA), and Fourier transform infrared spectroscopy (FTIR). Laser diffraction analysis indicated a median particle size (D₅₀) for spray-dried powders prepared from acetone, ethanol, and ethyl acetate of 5.4 ± 0.7, 5.2 ± 0.1, and 5.1 ± 0.0 μm respectively, which are appropriate sizes for pulmonary delivery by means of a dry powder inhaler. The solubility of the CAF/DAP cocrystal in phosphate buffer pH 7.4, prepared by spray drying using acetone, was 506.5 ± 31.5 μg/mL, while pure crystalline DAP had a measured solubility of 217.1 ± 7.8 μg/mL. In vitro cytotoxicity studies using Calu-3 cells indicated that the cocrystals were not toxic at concentrations of 0.1 and of 1 mM of DAP, while an in vitro permeability study suggested caffeine may contribute to the permeation of DAP by hindering the efflux effect. The results obtained indicate that the CAF/DAP cocrystal, particularly when prepared by the spray drying method, represents a possible suitable approach for inhalation formulations with applications in pulmonary pathologies.

Effect of sulfasalazine use on the presence of Pneumocystis organisms in the lung among patients with rheumatoid arthritis: A test-negative design case-control study with PCR tests

OBJECTIVE

To evaluate the effect of sulfasalazine (SSZ) on the presence of Pneumocystis jirovecii (P. jirovecii) in the lungs of rheumatoid arthritis (RA) patients.

METHODS

We retrospectively studied episodes of suspected P. jirovecii pneumonia (PJP) which were examined for P. jirovecii with polymerase chain reaction (PCR). We employed a test negative design case-control study; the cases were episodes of suspected PJP that were positive for PCR, and the controls were episodes of suspected PJP that were negative for PCR. The odds ratio for the positive PCR result associated with SSZ use was estimated by Firth's logistic regression.

RESULTS

Between 2003 and 2017, 36 cases and 83 controls were identified. While none of the cases received SSZ before the episode, 18 of the controls received the drug. In the primary analysis involving all the episodes, SSZ use was negatively associated with PCR positivity (adjusted odds ratio, 0.087; confidence interval, <0.001-0.789). The sensitivity analysis, excluding those who received PJP prophylaxis, showed the same association as the primary analysis (adjusted odds ratio 0.085, 95% CI <0.001-0.790).

CONCLUSION

This study demonstrated that SSZ use is associated with the absence of P. jirovecii in the lung, suggesting the preventive efficacy of the drug against PJP.

Development of Novel Chitosan Microcapsules for Pulmonary Delivery of Dapsone: Characterization, Aerosol Performance, and In Vivo Toxicity Evaluation

Pneumocystis carinii pneumonia (PCP) is a major opportunistic infection that affects patients with human immunodeficiency virus. Although orally administered dapsone leads to high hepatic metabolism, decreasing the therapeutic index and causing severe side effects, this drug is an effective alternative for the treatment of PCP. In this context, microencapsulation for pulmonary administration can offer an alternative to increase the bioavailability of dapsone, reducing its adverse effects. The aim of this work was to develop novel dapsone-loaded chitosan microcapsules intended for deep-lung aerosolized drug delivery. The geometric particle size (D 4,3) was approximately 7 μm, the calculated aerodynamic diameter (d aero) was approximately 4.5 μm, and the mass median aerodynamic diameter from an Andersen cascade impactor was 4.7 μm. The in vitro dissolution profile showed an efficient dapsone encapsulation, demonstrating the sustained release of the drug. The in vitro deposition (measured by the Andersen cascade impactor) showed an adequate distribution and a high fine particles fraction (FPF = 50%). Scanning electron microscopy of the pulmonary tissues demonstrated an adequate deposition of these particles in the deepest part of the lung. An in vivo toxicity experiment showed the low toxicity of the drug-loaded microcapsules, indicating a protective effect of the microencapsulation process when the particles are microencapsulated. In conclusion, the pulmonary administration of the novel dapsone-loaded microcapsules could be a promising alternative for PCP treatment.

Pneumocystis Pneumonia in Solid-Organ Transplant Recipients

Pneumocystis pneumonia (PCP) is well known and described in AIDS patients. Due to the increasing use of cytotoxic and immunosuppressive therapies, the incidence of this infection has dramatically increased in the last years in patients with other predisposing immunodeficiencies and remains an important cause of morbidity and mortality in solid-organ transplant (SOT) recipients. PCP in HIV-negative patients, such as SOT patients, harbors some specificity compared to AIDS patients, which could change the medical management of these patients. This article summarizes the current knowledge on the epidemiology, risk factors, clinical manifestations, diagnoses, prevention, and treatment of Pneumocystis pneumonia in solid-organ transplant recipients, with a particular focus on the changes caused by the use of post-transplantation prophylaxis.

Use of Oropharyngeal Washes to Diagnose and Genotype Pneumocystis jirovecii

Pneumocystis jirovecii is a symbiotic respiratory fungus that presents in 2 clinical forms: pneumonia in immunocompromised patients or colonization, defined by the presence of the organism without associated clinical symptoms. Currently, diagnosis requires invasive bronchoscopy, which may not be available in some settings and is inappropriate for detecting colonization in healthy individuals. Noninvasive diagnostic techniques and molecular strain typing tools that can be used on these samples are critical for conducting studies to better understand transmission. We evaluated 2 real-time polymerase chain reaction (PCR) assays targeting dihydropteroate synthase and the major surface glycoprotein for detection in 77 oropharyngeal washes (OPWs) from 43 symptomatic human immunodeficiency virus-infected patients who underwent bronchoscopy. We also evaluated the ability of a new microsatellite (MS) genotyping panel to strain type infections from these samples. Each PCR used individually provided a high sensitivity (>80%) for detection of pneumonia but a modest specificity (<70%). When used in combination, specificity was increased to 100% with a drop in sensitivity (74%). Concentration of organisms by PCR in the OPW tended to be lower in colonized individuals compared with those with pneumonia, but differences in concentration could not clearly define colonization in symptomatic individuals. Oropharyngeal wash samples were genotyped using 6 MSs with ≥4 alleles successfully genotyped in the majority of colonized patients and ≥5 alleles in patients with pneumonia. The MS profile was consistent over time within patients with serial OPWs analyzed. Microsatellite genotyping on noninvasive samples may aid in studying the molecular epidemiology of this pathogen without requiring invasive diagnostic techniques.

Trimethoprim-sulfamethoxazole treatment does not reverse obstructive pulmonary changes in pneumocystis-colonized nonhuman primates with SHIV infection

BACKGROUND

Despite antiretroviral therapy and trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis, Pneumocystis pneumonia remains an important serious opportunistic infection in HIV-infected persons. Pneumocystis (Pc) colonization in HIV-infected individuals and in HIV-uninfected smokers is associated with chronic obstructive pulmonary disease (COPD). We previously developed a nonhuman primate model of HIV infection and Pc colonization and demonstrated that Pc colonization correlated with COPD development. In the present study, we examined kinetics of COPD development in non-human primate and tested the effect of Pc burden reduction on pulmonary function by TMP-SMX treatment.

METHODS

Cynomolgus macaques (n = 16) were infected with simian/human immunodeficiency virus (SHIV89.6P), and natural Pc colonization was examined by nested polymerase chain reaction of serial bronchoalveolar lavage fluid and anti-Pc serology.

RESULTS

Eleven of 16 monkeys became Pc colonized by 16 weeks post simian-human immunodeficiency virus (SHIV) infection. Pc colonization of SHIV-infected monkeys led to progressive declines in pulmonary function as early as 4 weeks after Pc detection. SHIV-infected and Pc-negative monkeys maintained normal lung function. At 25 weeks post-SHIV infection, TMP-SMX treatment was initiated in 7 Pc-positive (Pc+) (TMP: 20 mg/kg and SMX: 100 mg/kg, daily for 48 weeks) and 5 Pc-negative (Pc-) monkeys. Four SHIV+/Pc+ remained untreated for the duration of the experiment. Detection frequency of Pc in serial bronchoalveolar lavage fluid (P < 0.001), as well as plasma Pc antibody titers (P = 0.02) were significantly reduced in TMP-SMX-treated macaques compared with untreated.

CONCLUSIONS

Reduction of Pc colonization by TMP-SMX treatment did not improve pulmonary function, supporting the concept that Pc colonization results in early, permanent obstructive changes in the lungs of immunosuppressed macaques.

Pneumocystis pneumonia in South African children diagnosed by molecular methods

Background

Pneumocystis pneumonia (PCP) is an important cause of hospitalization and mortality in HIV-infected children. However, the incidence of PCP has been underestimated due to poor sensitivity of diagnostic tests. The use of polymerase chain reaction (PCR) for pneumocystis has enabled more reliable diagnosis. This study describes the incidence, clinical features and outcome of PCP in South African children diagnosed using PCR.

Methods

A prospective study of children hospitalised in South Africa with suspected PCP was done from November 2006 to August 2008. Clinical, laboratory and radiological information were collected. Lower respiratory tract specimens were obtained for PCP immunofluorescence (IF), real- time PCR for pneumocystis, bacterial and mycobacterial culture. Nasopharyngeal aspirates were taken for immunofluorescence (IF), real-time PCR for pneumocystis and PCR for respiratory viruses. A blood specimen for bacterial culture and for cytomegalovirus PCR was taken. Children were followed for the duration of their hospitalisation and the outcome was recorded.

Results

202 children [median (interquartile range, IQR) age 3.2 (2.1– 4.6) months] were enrolled; 124 (61.4%) were HIV infected. PCP was identified in 109 (54%) children using PCR, compared to 43 (21%) using IF and Grocott staining (p < 0.0001). Most PCP cases (88, 81%) occurred in HIV-infected children. All 21 cases (19%) occurring in HIV- negative children had another risk factor for PCP. On logistic regression, predictive factors for PCP were HIV infection, lack of fever, high respiratory rate and low oxygen saturation whilst cotrimoxazole prophylaxis was protective (OR 0.24; 95% CI 0.1 to 0.5; p < 0.002). The case fatality of children with PCP was higher than those without PCP (32.1% versus 17.2%; relative risk 1.87; 95% confidence interval (CI) 1.11 – 3.15). Amongst HIV-infected children, a CD4 less than 15% was the only independent predictor of mortality.

Conclusions

The diagnostic yield for PCP is more than 2.5 times higher on PCR than other detection methods. PCP is a very common cause of severe hypoxic pneumonia and is associated with high mortality in HIV-infected African infants.

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.