Usefulness Of Oropharyngeal Washings For Identifying Pneumocystis jirovecii Carriers

Is It Possible to Differentiate Pneumocystis jirovecii Pneumonia and Colonization in the Immunocompromised Patients with Pneumonia?

Respiratory sample staining is a standard tool used to diagnose Pneumocystis jirovecii pneumonia (PjP). Although molecular tests are more sensitive, their interpretation can be difficult due to the potential of colonization. We aimed to validate a Pneumocystis jirovecii (Pj) real-time PCR (qPCR) assay in bronchoscopic bronchoalveolar lavage (BAL) and oropharyngeal washes (OW). We included 158 immunosuppressed patients with pneumonia, 35 lung cancer patients who underwent BAL, and 20 healthy individuals. We used a SYBR green qPCR assay to look for a 103 bp fragment of the Pj mtLSU rRNA gene in BAL and OW. We calculated the qPCR cut-off as well as the analytical and diagnostic characteristics. The qPCR was positive in 67.8% of BAL samples from the immunocompromised patients. The established cut-off for discriminating between disease and colonization was Ct 24.53 for BAL samples. In the immunosuppressed group, qPCR detected all 25 microscopy-positive PjP cases, plus three additional cases. Pj colonization in the immunocompromised group was 66.2%, while in the cancer group, colonization rates were 48%. qPCR was ineffective at diagnosing PjP in the OW samples. This new qPCR allowed for reliable diagnosis of PjP, and differentiation between PjP disease and colonization in BAL of immunocompromised patients with pneumonia.

Huertas C, Calderón EJ, Eritja R, Lechuga LM. Fast and Accurate Pneumocystis Pneumonia Diagnosis in Human Samples Using a Label-Free Plasmonic Biosensor

Pneumocystis jirovecii is a fungus responsible for human Pneumocystis pneumonia, one of the most severe infections encountered in immunodepressed individuals. The diagnosis of Pneumocystis pneumonia continues to be challenging due to the absence of specific symptoms in infected patients. Moreover, the standard diagnostic method employed for its diagnosis involves mainly PCR-based techniques, which besides being highly specific and sensitive, require specialized personnel and equipment and are time-consuming. Our aim is to demonstrate an optical biosensor methodology based on surface plasmon resonance to perform such diagnostics in an efficient and decentralized scheme. The biosensor methodology employs poly-purine reverse-Hoogsteen hairpin probes for the detection of the mitochondrial large subunit ribosomal RNA (mtLSU rRNA) gene, related to P. jirovecii detection. The biosensor device performs a real-time and label-free identification of the mtLSU rRNA gene with excellent selectivity and reproducibility, achieving limits of detection of around 2.11 nM. A preliminary evaluation of clinical samples showed rapid, label-free and specific identification of P. jirovecii in human lung fluids such as bronchoalveolar lavages or nasopharyngeal aspirates. These results offer a door for the future deployment of a sensitive diagnostic tool for fast, direct and selective detection of Pneumocystis pneumonia disease.

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.

Airborne acquisition of Pneumocystis in bronchoscopy units: a hidden danger to healthcare workers

The possible presence of Pneumocystis in a bronchoscopy unit of a tertiary-hospital was examined by detecting Pneumocystis-specific DNA by polymerase chain reaction in prospectively obtained samples of oropharyngeal wash from seven healthcare workers (HCWs) and air from three areas of the unit at different time points (baseline, days +15,+30,+60,+90 after initiation of the study). Positive samples were genotyped at two genetic loci: the mitochondrial large subunit ribosomal RNA (mtLSUrRNA) fragment by direct sequencing and the gene for dihydropteroate synthase (DHPS) by restriction fragment-length polymorphism. Pneumocystis DNA was identified in 13/24 samples from HCWs, in 4/14 air samples and also in two patients with Pneumocystis pneumonia (PcP) and another with a Pneumocystis-associated disease subjected to bronchoscopy on days +15 and +60 after initiation of the study. The HCWs harbored a high rate of mtLSU-rRNA genotypes 1 and 3 and samples from air and patients with only genotype 3. DHPS mutations related to sulpha resistance were detected in three samples from HCWs and in one from air; 65% of the positive samples showed genotypic concordance. The study demonstrates that HCWs of bronchoscopy units represent a new dynamic reservoir and a possible source of infection for human Pneumocystis species, including DHPS genotypes related to sulpha resistance that could be transmitted within hospitals to immunosuppressed hosts in whom a PcP can develop. The results provide the first evidence of the risk of Pneumocystis transmission in the bronchoscopy units and arguments to improve prevention and control of this infection in nosocomial setting.

Detection of Pneumocystis jirovecii by quantitative real-time PCR in oral rinses from Pneumocystis pneumonia asymptomatic human immunodeficiency virus patients

Pneumocystis pneumonia (PCP) is a potentially life-threatening fungal infection usually seen in immunocompromised patients. Pneumocystis jirovecii can be easily detected from oral rinse samples in HIV patients with suspected PCP. In this study, a quantitative real-time PCR assay was used to establish the frequency of detection of P. jirovecii in oral rinses from HIV patients without respiratory symptoms or suspicion of PCP. Two saline oral rinses were collected from 100 ambulant HIV patients and from 60 COPD patients (comparator group). Four HIV patients were positive for P. jirovecii. In three patients, the first sample was positive and in one the second one was positive. One of these patients was on PCP prophylaxis and had a CD4⁺ count of 76 cells/mm³. The mean CD4⁺ count for all patients was 527 cells/mm³. All qRT-PCR test results for the COPD patients were negative. No patient developed PCP at six months follow-up. The qRT-PCR assay can be used to detect P. jirovecii DNA in oral rinse samples from HIV patients without evident clinical symptoms, however the oral carriage of this fungus was rare in our cohort of patients. In conclusion, although rare, a positive oral rinse P. jirovecii result may reflect colonisation, in particular in patients with HIV. This needs to be kept in mind when using oral rinses and qRT-PCR in the diagnosis of P. jirovecii infection.

High prevalence of Pneumocystis jirovecii colonization among HIV-positive patients in southern Brazil

A high prevalence of Pneumocystis jirovecii colonization was observed in patients positive for the human immunodeficiency virus (HIV) admitted to a tertiary hospital in southern Brazil between August 2012 and December 2012. Amplification of the mitochondrial large subunit ribosomal RNA gene in oropharyngeal samples through nested polymerase chain reaction identified P. jirovecii colonization in 26 of 58 (44.8%) HIV-positive patients admitted for causes other than Pneumocystis pneumonia. Colonization was more frequent among patients with an absolute CD4 count ≤200 cells/μl. These findings suggest that the HIV-infected population is a major reservoir and source of P. jirovecii infection and that identification of such individuals may contribute to future strategies for improving management of HIV-infected patients.

Use of nasopharyngeal aspirate for diagnosis of pneumocystis pneumonia

Quantitative PCR on nasopharyngeal aspirate (NPA) can achieve high sensitivity and specificity in diagnosing Pneumocystis pneumonia (PCP) compared to microscopic examination of bronchoscopic specimens in a population with low HIV prevalence. Since NPA is a minimally invasive procedure, it is ideal as a screening test for PCP.

Pneumocystis jirovecii colonization in patients treated with infliximab

BACKGROUND

Infliximab, a chimeric antitumour necrosis factor (TNF) monoclonal antibody, has become an established effective therapy for inflammatory rheumatic disease. However, TNF is a critical factor in host defence, and the suppression of its biological activity may be associated with the increased risk of opportunistic infections. The frequent use of infliximab in clinical practice has identified Pneumocystis jirovecii pneumonia (PcP) as a serious complication. Individuals colonized with Pneumocystis may be at high risk of development of PcP when they have undergone immunosuppression. Hence, we addressed the question of the frequency of Pneumocystis colonization among patients treated with infliximab.

DESIGN

We examined 125 oropharyngeal washes collected from 78 individuals with rheumatoid arthritis, 30 with ankylosing spondylitis and 17 with psoriatic arthritis, half of them underwent infliximab therapy, using a real-time polymerase chain reaction assay that employs specific primers from a portion of the mitochondrial large-subunit rRNA gene of P. jirovecii.

RESULTS

Pneumocystis jirovecii colonization was detected in 32 (25·6%) patients. In a multivariate regression model, only duration of infliximab treatment for more than 3 years and use of corticosteroid were significantly and independently associated with risk of Pneumocystis colonization. However, the effect of corticosteroid on P. jirovecii colonization rate was not linearly dose dependent as showed other logistic regression analysis.

CONCLUSIONS

There is a high rate of P. jirovecii colonization among patients with rheumatologic diseases treated with infliximab. The identification of patients colonized by P. jirovecii before starting the treatment with infliximab could be a strategy for PcP prevention.

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

BACKGROUND

Pneumocystis colonization in young HIV-infected patients has been poorly studied. The aim of this study was to analyze the prevalence of P jiroveci colonization in a cohort of young HIV-infected patients.

MATERIAL AND METHODS

We designed a basal cross-sectional study in 20 young HIV-infected patients to determine the prevalence of P jiroveci colonization in oropharyngeal wash samples studied by nested polymerase chain reaction (PCR). Subsequently, patients were followed up during 50 weeks to observe the development of Pneumocystis pneumonia (PCP).

RESULTS

P jiroveci colonization was detected in eight (40%) of the 20 oropharyngeal wash samples. Genotype 85C/248C was the most frequent. After 50 weeks of follow-up, one colonized patient with advanced immunodepression developed PCP.

CONCLUSIONS

We have found a high prevalence of P jiroveci colonization in young HIV-infected patients with a major prevalence of genotype 1 (85C/248C). Further studies are necessary to clarify if Pneumocystis colonization could be a potential risk factor of developing PCP in young HIV infected patients.

Pulmonary diseases associated with inflammatory bowel diseases

Among the extra-intestinal manifestations of inflammatory bowel diseases, those involving the lung are relatively rare. However, there is a wide array of such manifestations, spanning from drug-related pathologies to airway disease, fistulas, granulomatous diseases, autoimmune and thromboembolic disorders. Although infrequent, people dealing with inflammatory bowel diseases must be aware of these conditions, sometimes life-threatening, to avoid further impairment of the health status of the patients and to alleviate their symptoms by prompt recognition and treatment.