Evaluation of Toluidine Blue O Staining for the Diagnosis of Pneumocystis jiroveci in Expectorated Sputum Sample and Bronchoalveolar Lavage from HIV-infected Patients in a Tertiary Care Referral Center in Ethiopia

The Burden of Pneumocystis Pneumonia Infection among HIV Patients in Ethiopia: A Systematic Review

Pneumocystis pneumonia (PCP) is a leading cause of death among patients with AIDS worldwide, but its burden is difficult to estimate in low- and middle-income countries, including Ethiopia. This systematic review aimed to estimate the pooled prevalence of PCP in Ethiopia, the second most densely populated African country. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were used to review published and unpublished studies conducted in Ethiopia. Studies that reported on the prevalence of PCP among HIV-infected patients were searched systematically. Variations between the studies were assessed by using forest plot and I-squared heterogeneity tests. Subgroup and sensitivity analyses were carried out when I2 > 50. The pooled estimate prevalence with 95% CI was computed using a random-effects model of analysis. Thirteen articles, comprising studies of 4847 individuals living with HIV, were included for analysis. The pooled prevalence of PCP was 5.65% (95% CI [3.74-7.56]) with high heterogeneity (I2 = 93.6%, p < 0.01). To identify the source of heterogeneity, subgroup analyses were conducted by study design, geographical region, diagnosis methods, and year of publication. PCP prevalence differed significantly when biological diagnostic methods were used (32.25%), in studies published before 2010 (32.51%), in cross-sectional studies (8.08%), and in Addis Ababa (14.05%). PCP prevalence differences of 3.25%, 3.07%, 3.23%, and 2.29% were recorded in studies based on clinical records, published since 2017, follow-up studies, and north-west Ethiopian studies, respectively. The prevalence of PCP is probably underestimated, as the reports were mainly based on clinical records. An expansion of biological diagnostic methods could make it possible to estimate the exact burden of PCP in Ethiopia.

Non-invasive diagnosis of Pneumocystis jirovecii pneumonia: a systematic review and meta-analysis

BACKGROUND

Pneumocystis jirovecii pneumonia (PCP) is an opportunistic infection commonly affecting immunocompromised people. Diagnosis usually requires invasive techniques to obtain respiratory specimens. Minimally invasive detection tests have been proposed, but their operating characteristics are poorly described.

OBJECTIVES

To systematically review and meta-analyse the performance of minimally invasive PCP detection tests to inform diagnostic algorithms.

DATA SOURCES

Medline, Embase, Cochrane Library (inception to 15 October 2020).

STUDY ELIGIBILITY CRITERIA

Studies of minimally invasive PCP detection tests were included if they contained a minimum of ten PCP cases.

PARTICIPANTS

Adults at risk of PCP.

TESTS

Non-invasive PCP detection tests.

REFERENCE STANDARD

Diagnosis using the combination of clinical and radiographical features with invasive sampling.

ASSESSMENT OF RISK BIAS

Using the QUADAS-2 tool.

METHODS

We used bivariate and, when necessary, univariate analysis models to estimate diagnostic test sensitivity and specificity.

RESULTS

Fifty-two studies were included; most studies (40) comprised exclusively human immunodeficiency virus (HIV) -infected individuals; nine were mixed (HIV and non-HIV), two were non-HIV and one study did not report HIV status. Sampling sites included induced sputum, nasopharyngeal aspirate, oral wash and blood. The four testing modalities evaluated were cytological staining, fluorescent antibody, PCR and lactate dehydrogenase. Induced sputum had the most data available; this modality was both highly sensitive at 99% (95% CI 51%-100%) and specific at 96% (95% CI 88%-99%). Induced sputum cytological staining had moderate sensitivity at 50% (95% CI 39%-61%) and high specificity at 100% (95% CI 100%-100%), as did fluorescent antibody testing with sensitivity 74% (95% CI 62%-87%) and specificity 100% (95% CI 91%-100%).

CONCLUSION

There are several promising minimally invasive PCP diagnostic tests available, some of which may reduce the need for invasive respiratory sampling. Understanding the operating characteristics of these tests can augment current diagnostic strategies and help establish a more confident clinical diagnosis of PCP. Further studies in non-HIV infected populations are needed.

Using Routine Laboratory Markers and Immunological Indicators for Predicting Pneumocystis jiroveci Pneumonia in Immunocompromised Patients

Background

Pneumocystis jiroveci pneumonia (PJP) is the most common opportunistic infection in immunocompromised patients. The accurate prediction of PJP development in patients undergoing immunosuppressive therapy remains challenge.

Methods

Patients undergoing immunosuppressive treatment and with confirmed pneumocystis jiroveci infection were enrolled. Another group of matched patients with immunosuppressant treatment but without signs of infectious diseases were enrolled to control group.

Results

A total of 80 (40 PJP, 40 non-PJP) participants were enrolled from Tongji Hospital. None of the patients were HIV positive. The routine laboratory indicators, such as LYM, MON, RBC, TP, and ALB, were significantly lower in PJP patients than in non-PJP patients. Conversely, LDH in PJP patients was significantly higher than in non-PJP controls. For immunological indicators, the numbers of T, B, and NK cells were all remarkably lower in PJP patients than in non-PJP controls, whereas the functional markers such as HLA-DR, CD45RO and CD28 expressed on CD4⁺ or CD8⁺ T cells had no statistical difference between these two groups. Cluster analysis showing that decrease of host immunity markers including CD3⁺, CD4⁺ and CD8⁺ T cells, and increase of tissue damage marker LDH were the most typical characteristics of PJP patients. A further established model based on combination of CD8⁺ T cells and LDH showed prominent value in distinguishing PJP from non-PJP, with AUC of 0.941 (95% CI, 0.892-0.990).

Conclusions

A model based on combination of routine laboratory and immunological indicators shows prominent value for predicting the development of PJP in HIV-negative patients undergoing immunosuppressive therapy.

Pneumocystis jirovecii Pneumonia in Children with Hematological Malignancies: Diagnosis and Approaches to Management

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection that mostly affects children with suppressed cellular immunity. PJP was the most common cause of infectious death in children with acute lymphoblastic leukemia prior to the inclusion of cotrimoxazole prophylaxis as part of the standard medical care in the late 1980s. Children with acute leukemia, lymphomas, and those undergoing hematopoietic stem cell transplantation, especially allogeneic transplantation, are also at high risk of PJP. Persistent lymphopenia, graft versus host disease, poor immune reconstitution, and lengthy use of corticosteroids are significant risk factors for PJP. Active infection may be due to reactivation of latent infection or recent acquisition from environmental exposure. Intense hypoxemia and impaired diffusing capacity of the lungs are hallmarks of PJP, while computerized tomography of the lungs is the diagnostic technique of choice. Immunofluorescence testing with monoclonal antibodies followed by fluorescent microscopy and polymerase chain reaction testing of respiratory specimens have emerged as the best diagnostic methods. Measurement of (1-3)-β-D-glucan in the serum has a high negative predictive value in ruling out PJP. Oral cotrimoxazole is effective for prophylaxis, but in intolerant patients, intravenous and aerosolized pentamidine, dapsone, and atovaquone are effective alternatives. Ιntravenous cotrimoxazole is the treatment of choice, but PJP has a high mortality even with appropriate therapy.

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.

The Burden of Fungal Infections in Ethiopia

The burden of severe fungal infections (FIs) is not well addressed in Ethiopia. We have estimated the burden of FIs from multiple demographic sources and by searching articles from PubMed. Opportunistic FIs were estimated using modelling and 2017 national HIV data. The burdens of chronic pulmonary aspergillosis (CPA) and allergic bronchopulmonary aspergillosis (ABPA) were estimated by using the prevalence of asthma, chronic obstructive pulmonary disease, and annual the incidence of tuberculosis. Of the 105,000,000 estimated Ethiopian population, 610,000 are thought to have HIV infection. Our estimation of HIV-related FIs were: 9900 cryptococcal meningitis (CM), 12,700 Pneumocystis jirovecii pneumonia (PCP), 76,300 oral and 56,000 oesophageal candidiasis cases. A remarkable 7,051,700 4–14-year-olds probably have tinea capitis and 1,469,000 women probably have recurrent Candida vaginitis. There were 15,200 estimated CPA cases (prevalence) and 11,500 invasive aspergillosis (IA) cases (incidence). Data are scant, but we estimated 5300 candidaemia and 800 Candida peritonitis cases. In conclusion, approximately 8% of Ethiopians suffer from FIs annually, mostly schoolchildren with tinea capitis. IA, CM and PCP are the major causes of fungal deaths. The absence of CD4 count is challenging the identification of HIV patients at risk of opportunistic FIs. There is a pressing need to improve FI diagnosis, probably including national surveillance.

Copy Number Variation of Mitochondrial DNA Genes in Pneumocystis jirovecii According to the Fungal Load in BAL Specimens

Pneumocystis jirovecii is an unculturable fungus and the causative agent of Pneumocystis pneumonia, a life-threatening opportunistic infection. Although molecular diagnosis is often based on the detection of mtLSU rRNA mitochondrial gene, the number of copies of mitochondrial genes had not been investigated. We developed and optimized six real-time PCR assays in order to determine the copy number of four mitochondrial genes (mtSSU rRNA, mtLSU rRNA, NAD1, and CYTB) in comparison to nuclear genome (DHPS and HSP70) and tested 84 bronchoalveolar fluids of patients at different stages of the infection. Unexpectedly, we found that copy number of mitochondrial genes varied from gene to gene with mtSSU rRNA gene being more represented (37 copies) than NAD1 (23 copies), mtLSU rRNA (15 copies) and CYTB (6 copies) genes compared to nuclear genome. Hierarchical clustering analysis (HCA) allowed us to define five major clusters, significantly associated with fungal load (p = 0.029), in which copy number of mitochondrial genes was significantly different among them. More importantly, copy number of mtLSU rRNA, NAD1, and CYTB but not mtSSU rRNA differed according to P. jirovecii physiological state with a decreased number of copies when the fungal load is low. This suggests the existence of a mixture of various subspecies of mtDNA that can harbor different amplification rates. Overall, we revealed here an unexpected variability of P. jirovecii mtDNA copy number that fluctuates according to P. jirovecii’s physiological state, except for mtSSU that is the most stable and the most present mitochondrial gene.

ECIL guidelines for the diagnosis of Pneumocystis jirovecii pneumonia in patients with haematological malignancies and stem cell transplant recipients

The Fifth European Conference on Infections in Leukaemia (ECIL-5) convened a meeting to establish evidence-based recommendations for using tests to diagnose Pneumocystis jirovecii pneumonia (PCP) in adult patients with haematological malignancies. Immunofluorescence assays are recommended as the most sensitive microscopic method (recommendation A-II: ). Real-time PCR is recommended for the routine diagnosis of PCP ( A-II: ). Bronchoalveolar lavage (BAL) fluid is recommended as the best specimen as it yields good negative predictive value ( A-II: ). Non-invasive specimens can be suitable alternatives ( B-II: ), acknowledging that PCP cannot be ruled out in case of a negative PCR result ( A-II: ). Detecting β-d-glucan in serum can contribute to the diagnosis but not the follow-up of PCP ( A-II: ). A negative serum β-d-glucan result can exclude PCP in a patient at risk ( A-II: ), whereas a positive test result may indicate other fungal infections. Genotyping using multilocus sequence markers can be used to investigate suspected outbreaks ( A-II: ). The routine detection of dihydropteroate synthase mutations in cases of treatment failure is not recommended ( B-II: ) since these mutations do not affect response to high-dose co-trimoxazole. The clinical utility of these diagnostic tests for the early management of PCP should be further assessed in prospective, randomized interventional studies.

[Pneumocystis pneumonia biological diagnosis at Fann Teaching Hospital in Dakar, Senegal]

BACKGROUND

Data relative to Pneumocystis pneumonia in sub-Saharan Africa are not well known. Weakness of the technical material and use of little sensitive biological tools of diagnosis are among the evoked reasons. The objective of this study is to update the data of the disease at the Fann Teaching Hospital in Dakar and to estimate biological methods used in diagnosis.

MATERIALS AND METHODS

A descriptive longitudinal study was carried out from January 5th, 2009 to October 31st, 2011 in the parasitology and mycology laboratory of the Fann Teaching Hospital in Dakar. The bronchoalveolar lavages received in the laboratory were examined microscopically for Pneumocystis jirovecii by indirect fluorescent assay or after Giemsa or toluidine blue O staining.

RESULTS

One hundred and eighty-three bronchoalveolar lavages withdrawn from 183 patients were received in the laboratory. Sixteen were positive for P. jirovecii at 9% frequency. Four among these patients were HIV positive. Indirect fluorescent assay allowed finding of P. jirovecii among 16 patients while Giemsa staining discovered P. jirovecii only in a single patient. No case was diagnosed by toluidine blue O staining.

CONCLUSION

Pneumocystis pneumonia in Parasitology and Mycology Laboratory of Fann Teaching Hospital at Dakar was mainly diagnosed among HIV patients.

Three cases of presumed pneumocystis pneumonia in patients receiving bortezomib therapy for multiple myeloma

INTRODUCTION

This paper presents three probable cases of pneumocystis pneumonia in patients receiving bortezomib therapy for multiple myeloma.

PRESENTATION OF CASES

Three patients receiving bortezomib therapy for multiple myeloma presented with dyspnoea, non-productive cough, and fevers. These patients deteriorated despite receiving broad-spectrum antibiotic therapy with piperacillin + tazobactam and azithromycin and an assortment of other antimicrobials but promptly responded to sulfamethoxazole + trimethoprim therapy. Only one of the patients exhibited a positive Pneumocystis jirovecii PCR test but testing was sub-optimal.

DISCUSSION

Although only one of the patients exhibited a positive sputum P. jirovecii PCR test, the diagnosis of PCP in these three patients is supported by their; clinical and radiological features consistent with PCP, deterioration despite receiving broad-spectrum antibiotic therapy, and prompt responses to sulfamethoxazole + trimethoprim therapy. In the patients with negative P. jirovecii PCR bronchoalveolar lavage specimens were not obtained as these patients were deemed too high risk to undergo the procedure. Although the three patients were also receiving dexamethasone therapy, the doses and durations were at the threshold of those expected to cause PCP.

CONCLUSION

26S proteosome inhibitor therapy for multiple myeloma may be a risk factor for PCP and clinicians should adopt a high level of suspicion for PCP in patients receiving these medications until conclusive evidence is obtained.

Pneumocystis jirovecii pneumonia in developing countries

Pneumocystis pneumonia (PcP) is a serious fungal infection among immunocompromised patients. In developed countries, the epidemiology and clinical spectrum of PcP have been clearly defined and well documented. However, in most developing countries, relatively little is known about the prevalence of pneumocystosis. Several articles covering African, Asian and American countries were reviewed in the present study. PcP was identified as a frequent opportunistic infection in AIDS patients from different geographic regions. A trend to an increasing rate of PcP was apparent in developing countries from 2002 to 2010.

Cost-effectiveness analysis of diagnostic options for pneumocystis pneumonia (PCP)

Background

Diagnosis of Pneumocystis jirovecii pneumonia (PCP) is challenging, particularly in developing countries. Highly sensitive diagnostic methods are costly, while less expensive methods often lack sensitivity or specificity. Cost-effectiveness comparisons of the various diagnostic options have not been presented.

Methods and Findings

We compared cost-effectiveness, as measured by cost per life-years gained and proportion of patients successfully diagnosed and treated, of 33 PCP diagnostic options, involving combinations of specimen collection methods [oral washes, induced and expectorated sputum, and bronchoalveolar lavage (BAL)] and laboratory diagnostic procedures [various staining procedures or polymerase chain reactions (PCR)], or clinical diagnosis with chest x-ray alone. Our analyses were conducted from the perspective of the government payer among ambulatory, HIV-infected patients with symptoms of pneumonia presenting to HIV clinics and hospitals in South Africa. Costing data were obtained from the National Institutes of Communicable Diseases in South Africa. At 50% disease prevalence, diagnostic procedures involving expectorated sputum with any PCR method, or induced sputum with nested or real-time PCR, were all highly cost-effective, successfully treating 77–90% of patients at $26–51 per life-year gained. Procedures using BAL specimens were significantly more expensive without added benefit, successfully treating 68–90% of patients at costs of $189–232 per life-year gained. A relatively cost-effective diagnostic procedure that did not require PCR was Toluidine Blue O staining of induced sputum ($25 per life-year gained, successfully treating 68% of patients). Diagnosis using chest x-rays alone resulted in successful treatment of 77% of patients, though cost-effectiveness was reduced ($109 per life-year gained) compared with several molecular diagnostic options.

Conclusions

For diagnosis of PCP, use of PCR technologies, when combined with less-invasive patient specimens such as expectorated or induced sputum, represent more cost-effective options than any diagnostic procedure using BAL, or chest x-ray alone.

Evidence for high prevalence of Pneumocystis jirovecii exposure among Cameroonians

Cameroon lacks the capacity for routine Pneumocystis pneumonia (PcP) diagnosis, thus, the prevalence of Cameroonian exposure to this microbe is unknown. It is known that Pneumocystis infecting different mammalian host species represent diverse phylogenetic backgrounds and are now designated as separate species. The highly sensitive nature of ELISA and the specificity afforded by using human-derived P. jirovecii Msg peptides has been shown to be useful for serological analysis of human sera. Thus, sera from patients in Yaoundé, the capital city of Cameroon, were analyzed for anti-P. jirovecii antibodies by enzyme-linked immunosorbent assay (ELISA) using three recombinant major surface glycoprotein (Msg) peptide fragments, MsgA1, MsgB, and MsgC1. Based on serum recognition of one or more of the three fragments, 82% of the total samples analyzed was positive for antibodies to P. jirovecii Msg, indicating high prevalence of P. jirovecii infection or colonization among Cameroonians. Different Msg fragments appear to be recognized more frequently by sera from different geographic regions of the globe. Antibodies in the Cameroonian serum samples recognized MsgA1>MsgC1>MsgB, suggesting that different P. jirovecii strains exist in different parts of the world and/or human populations differ in their response to P. jirovecii. Also, HIV(+) patients diagnosed with respiratory infections (such as TB and pneumonia) and maintained on trimethoprim/sulfamethoxazol prophylaxis had relatively lower anti-Msg titers. Whether PcP prophylaxis has significant effects on the quality of life among HIV(+) patients in Cameroon warrants further investigation.