Pneumocystis jirovecii pneumonia in people living with HIV: a review.

Pneumocystis jirovecii is a ubiquitous opportunistic fungus that can cause life-threatening pneumonia. People with HIV (PWH) who have low CD4 counts are one of the populations at the greatest risk of Pneumocystis jirovecii pneumonia (PCP). While guidelines have approached the diagnosis, prophylaxis, and management of PCP, the numerous studies of PCP in PWH are dominated by the 1980s and 1990s. As such, most studies have included younger male populations, despite PCP affecting both sexes and a broad age range. Many studies have been small and observational in nature, with an overall lack of randomized controlled trials. In many jurisdictions, and especially in low- and middle-income countries, the diagnosis can be challenging due to lack of access to advanced and/or invasive diagnostics. Worldwide, most patients will be treated with 21 days of high-dose trimethoprim sulfamethoxazole, although both the dose and the duration are primarily based on historical practice. Whether treatment with a lower dose is as effective and less toxic is gaining interest based on observational studies. Similarly, a 21-day tapering regimen of prednisone is used for patients with more severe disease, yet other doses, other steroids, or shorter durations of treatment with corticosteroids have not been evaluated. Now with the widespread availability of antiretroviral therapy, improved and less invasive PCP diagnostic techniques, and interest in novel treatment strategies, this review consolidates the scientific body of literature on the diagnosis and management of PCP in PWH, as well as identifies areas in need of more study and thoughtfully designed clinical trials.

Rapid phenotypic testing for detection of carbapenemase- or extended-spectrum ß-lactamase-producing Enterobacterales directly from blood cultures: a systematic review and meta-analysis.

BACKGROUND: Early identification of extended-spectrum ß-lactamase (ESBL) and carbapenemase-producing Enterobacterales (CP-CRE) is critical for timely therapy. Rapid phenotypic tests identifying these resistance mechanisms from pure bacterial colonies have been developed. OBJECTIVES: To determine the operating characteristics of available rapid phenotypic tests when applied directly to positive blood cultures. METHODS OF DATA SYNTHESIS: Bivariate random effects models were used unless convergence was not achieved where we used separate univariate models for sensitivity and specificity. DATA SOURCES: MEDLINE, CENTRAL, Embase, BIOSIS, and Scopus from inception to 16 March 2021. STUDY ELIGIBILITY CRITERIA: Studies using any rapid phenotypic assay for detection of ESBL or CP-CRE directly from blood cultures positive for Enterobacterales, including those utilizing spiked blood cultures. Case reports/series, posters, abstracts, review articles, those with ≤5 resistant isolates, and studies lacking data or without full text were excluded. PARTICIPANTS: Consecutive patient samples (main analysis) or spiked blood cultures (sensitivity analysis). TESTS: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry assays (MALDI-TOF) and commercially available chromogenic or immunogenic assays. REFERENCE STANDARD: Conventional laboratory methods and/or polymerase chain reaction (PCR). ASSESSMENT OF RISK OF BIAS: Quality Assessment of Diagnostic Accuracy Studies Version 2 (QUADAS-2). RESULTS: For detection of the ESBL phenotype the respective pooled sensitivities and specificities for consecutive clinical samples were as follows: 94% (95% CI 93-99%) and 97% (95% CI 95-100%) for MALDI-TOF/mass spectrometry (n = 1); and 98% (95% CI 92-100%) and 100% (95% CI 96-100%) for chromogenic assays (n = 7). For the CP-CRE phenotype the respective pooled sensitivity and specificities for consecutive clinical samples were as follows: 100% (95% CI 99-100%) and 100% (95% CI 100-100%) for MALDI-TOF (n = 2); 96% (95% CI 77-99%) and 100% (95% CI 81-100%) for chromogenic assays (n = 4); and 98% (95% CI 96-100%) and 100% (95% CI 100-100%) for immunogenic testing (n = 2). CONCLUSIONS: Rapid phenotypic assays that can be directly applied to positive blood cultures to detect ESBL and carbapenemase production from Enterobacterales exist and, although clinical studies are limited, they appear to have high sensitivity and specificity. Their potential to facilitate patient care through timely identification of bacterial resistance should be further explored.

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.

Characteristics and outcomes of patients with COVID-19 admitted to hospital and intensive care in the first phase of the pandemic in Canada: a national cohort study.

BACKGROUND: Clinical data on patients admitted to hospital with coronavirus disease 2019 (COVID-19) provide clinicians and public health officials with information to guide practice and policy. The aims of this study were to describe patients with COVID-19 admitted to hospital and intensive care, and to investigate predictors of outcome to characterize severe acute respiratory infection. METHODS: This observational cohort study used Canadian data from 32 selected hospitals included in a global multisite cohort between Jan. 24 and July 7, 2020. Adult and pediatric patients with a confirmed diagnosis of COVID-19 who received care in an intensive care unit (ICU) and a sampling of up to the first 60 patients receiving care on hospital wards were included. We performed descriptive analyses of characteristics, interventions and outcomes. The primary analyses examined in-hospital mortality, with secondary analyses of the length of hospital and ICU stay. RESULTS: Between January and July 2020, among 811 patients admitted to hospital with a diagnosis of COVID-19, the median age was 64 (interquartile range [IQR] 53-75) years, 495 (61.0%) were men, 46 (5.7%) were health care workers, 9 (1.1%) were pregnant, 26 (3.2%) were younger than 18 years and 9 (1.1%) were younger than 5 years. The median time from symptom onset to hospital admission was 7 (IQR 3-10) days. The most common symptoms on admission were fever, shortness of breath, cough and malaise. Diabetes, hypertension and cardiac, kidney and respiratory disease were the most common comorbidities. Among all patients, 328 received care in an ICU, admitted a median of 0 (IQR 0-1) days after hospital admission. Critically ill patients received treatment with invasive mechanical ventilation (88.8%), renal replacement therapy (14.9%) and extracorporeal membrane oxygenation (4.0%); 26.2% died. Among those receiving mechanical ventilation, 31.2% died. Age was an influential predictor of mortality (odds ratio per additional year of life 1.06, 95% confidence interval 1.03-1.09). INTERPRETATION: Patients admitted to hospital with COVID-19 commonly had fever, respiratory symptoms and comorbid conditions. Increasing age was associated with the development of critical illness and death; however, most critically ill patients in Canada, including those requiring mechanical ventilation, survived and were discharged from hospital.

On the Treatment of Pneumocystis jirovecii Pneumonia: Current Practice Based on Outdated Evidence.

Pneumocystis jirovecii pneumonia (PCP) is a common opportunistic infection causing more than 400000 cases annually worldwide. Although antiretroviral therapy has reduced the burden of PCP in persons with human immunodeficiency virus (HIV), an increasing proportion of cases occur in other immunocompromised populations. In this review, we synthesize the available randomized controlled trial (RCT) evidence base for PCP treatment. We identified 14 RCTs that were conducted 25-35 years ago, principally in 40-year-old men with HIV. Trimethoprim-sulfamethoxazole, at a dose of 15-20 mg/kg per day, is the treatment of choice based on historical practice rather than on quality comparative, dose-finding studies. Treatment duration is similarly based on historical practice and is not evidence based. Corticosteroids have a demonstrated role in hypoxemic patients with HIV but have yet to be studied in RCTs as an adjunctive therapy in non-HIV populations. The echinocandins are potential synergistic treatments in need of further investigation.

Radiographic features in investigated for Pneumocystis jirovecii pneumonia: a nested case-control study.

BACKGROUND: Pneumocystis jirovecii pneumonia (PJP) can be challenging to diagnose, often requiring bronchoscopy. Since most patients suspected of PJP undergo imaging, we hypothesized that the findings of these studies could help estimate the probability of disease prior to invasive testing. METHODS: We created a cohort of patients who underwent bronchoscopy specifically to diagnose PJP and conducted a nested case-control study to compare the radiographic features between patients with (n = 72) and without (n = 288) pathologically proven PJP. We used multivariable logistic regression to identify radiographic features independently associated with PJP. RESULTS: Chest x-ray findings poorly predicted the diagnosis of PJP. However, multivariable analysis of CT scan findings found that "increased interstitial markings" (OR 4.3; 95%CI 2.2-8.2), "ground glass opacities" (OR 3.3; 95%CI 1.2-9.1) and the radiologist's impression of PJP being "possible" (OR 2.0; 95%CI 1.0-4.1) or "likely" (OR 9.3; 95%CI 3.4-25.3) were independently associated with the final diagnosis (c-statistic 0.75). CONCLUSIONS: Where there is clinical suspicion of PJP, the use of CT scan can help determine the probability of PJP. Identifying patients at low risk of PJP may enable better use of non-invasive testing to avoid bronchoscopy while higher probability patients could be prioritized.