Pneumococcal urinary antigen test: diagnostic yield and impact on antibiotic treatment: Pneumococcal antigen test in clinical practice

Derivation and external validation of a prediction model for pneumococcal urinary antigen test positivity in patients with community-acquired pneumonia

Objective

Derive and externally validate a prediction model for pneumococcal urinary antigen test (pUAT) positivity.

Methods

Retrospective cohort study of adults admitted with community-acquired pneumonia (CAP) to 177 U.S. hospitals in the Premier Database (derivation and internal validation samples) or 12 Cleveland Clinic hospitals (external validation sample). We utilized multivariable logistic regression to predict pUAT positivity in the derivation dataset, followed by model performance evaluation in both validation datasets. Potential predictors included demographics, comorbidities, clinical findings, and markers of disease severity.

Results

Of 198,130 Premier patients admitted with CAP, 27,970 (14.1%) underwent pUAT; 1962 (7.0%) tested positive. The strongest predictors of pUAT positivity were history of pneumococcal infection in the previous year (OR 6.99, 95% CI 4.27-11.46), severe CAP on admission (OR 1.76, 95% CI 1.56-1.98), substance abuse (OR 1.57, 95% CI 1.27-1.93), smoking (OR 1.23, 95% CI 1.09-1.39), and hyponatremia (OR 1.35, 95% CI 1.17-1.55). Negative predictors included IV antibiotic use in past year (OR 0.65, 95% CI 0.52-0.82), congestive heart failure (OR 0.72, 95% CI 0.63-0.83), obesity (OR 0.71, 95% CI 0.60-0.85), and admission from skilled nursing facility (OR 0.60, 95% CI 0.45-0.78). Model c-statistics were 0.60 and 0.67 in the internal and external validation cohorts, respectively. Compared to guideline-recommended testing of severe CAP patients, our model would have detected 23% more cases with 5% fewer tests.

Conclusion

Readily available data can identify patients most likely to have a positive pUAT. Our model could be incorporated into automated clinical decision support to improve test efficiency and antimicrobial stewardship.

Diagnostic accuracy of urinary antigen tests for pneumococcal pneumonia among patients with acute respiratory failure suspected pneumonia: a systematic review and meta-analysis

BACKGROUND/OBJECTIVES

Urinary antigen tests have been used for the rapid identification of Streptococcus pneumoniae infection in patients with pneumonia, thereby leading to earlier targeted therapy than when using conventional diagnostic culture methods. This study aimed to update the knowledge on the diagnostic accuracy of urinary antigen tests for S. pneumoniae among patients with acute respiratory failure suspected of pneumonia based on a systematic review and meta-analysis.

METHODS

A systematic search was performed using MEDLINE and the Cochrane Central Register of Controlled Trials for studies published up to 3 June 2020. Prospective and retrospective cohort studies (in English) that reported on the diagnostic performance of urinary antigen tests versus culture or smear diagnostic methods in adult patients with clinically diagnosed pneumonia were selected and analysed. The QUADAS-2 tool was used to assess the risk of bias, and a bivariate random effects model was applied to perform a meta-analysis of the selected studies.

RESULTS

A total of 2179 studies were screened, of which 30 met the eligibility criteria for quality assessment and meta-analysis. Overall, data from 12 366 patients, including 1548 patients (12.5%) with the target condition and suspected pneumococcal pneumonia, were included in the analysis. The overall quality of the included studies was determined to be serious. The calculated pooled sensitivity and specificity were of 0.66 (95% CI 0.62 to 0.69) and 0.90 (95% CI 0.85 to 0.93), respectively.

CONCLUSIONS

The urinary antigen test is useful for achieving a definitive diagnosis of S. pneumoniae infection in patients with pneumonia.

ARDS Clinical Practice Guideline 2021

BACKGROUND

The joint committee of the Japanese Society of Intensive Care Medicine/Japanese Respiratory Society/Japanese Society of Respiratory Care Medicine on ARDS Clinical Practice Guideline has created and released the ARDS Clinical Practice Guideline 2021.

METHODS

The 2016 edition of the Clinical Practice Guideline covered clinical questions (CQs) that targeted only adults, but the present guideline includes 15 CQs for children in addition to 46 CQs for adults. As with the previous edition, we used a systematic review method with the Grading of Recommendations Assessment Development and Evaluation (GRADE) system as well as a degree of recommendation determination method. We also conducted systematic reviews that used meta-analyses of diagnostic accuracy and network meta-analyses as a new method.

RESULTS

Recommendations for adult patients with ARDS are described: we suggest against using serum C-reactive protein and procalcitonin levels to identify bacterial pneumonia as the underlying disease (GRADE 2D); we recommend limiting tidal volume to 4-8 mL/kg for mechanical ventilation (GRADE 1D); we recommend against managements targeting an excessively low SpO2 (PaO2) (GRADE 2D); we suggest against using transpulmonary pressure as a routine basis in positive end-expiratory pressure settings (GRADE 2B); we suggest implementing extracorporeal membrane oxygenation for those with severe ARDS (GRADE 2B); we suggest against using high-dose steroids (GRADE 2C); and we recommend using low-dose steroids (GRADE 1B). The recommendations for pediatric patients with ARDS are as follows: we suggest against using non-invasive respiratory support (non-invasive positive pressure ventilation/high-flow nasal cannula oxygen therapy) (GRADE 2D), we suggest placing pediatric patients with moderate ARDS in the prone position (GRADE 2D), we suggest against routinely implementing NO inhalation therapy (GRADE 2C), and we suggest against implementing daily sedation interruption for pediatric patients with respiratory failure (GRADE 2D).

CONCLUSIONS

This article is a translated summary of the full version of the ARDS Clinical Practice Guideline 2021 published in Japanese (URL: https://www.jsicm.org/publication/guideline.html ). The original text, which was written for Japanese healthcare professionals, may include different perspectives from healthcare professionals of other countries.

ARDS clinical practice guideline 2021

BACKGROUND

The joint committee of the Japanese Society of Intensive Care Medicine/Japanese Respiratory Society/Japanese Society of Respiratory Care Medicine on ARDS Clinical Practice Guideline has created and released the ARDS Clinical Practice Guideline 2021.

METHODS

The 2016 edition of the Clinical Practice Guideline covered clinical questions (CQs) that targeted only adults, but the present guideline includes 15 CQs for children in addition to 46 CQs for adults. As with the previous edition, we used a systematic review method with the Grading of Recommendations Assessment Development and Evaluation (GRADE) system as well as a degree of recommendation determination method. We also conducted systematic reviews that used meta-analyses of diagnostic accuracy and network meta-analyses as a new method.

RESULTS

Recommendations for adult patients with ARDS are described: we suggest against using serum C-reactive protein and procalcitonin levels to identify bacterial pneumonia as the underlying disease (GRADE 2D); we recommend limiting tidal volume to 4-8 mL/kg for mechanical ventilation (GRADE 1D); we recommend against managements targeting an excessively low SpO₂ (PaO₂) (GRADE 2D); we suggest against using transpulmonary pressure as a routine basis in positive end-expiratory pressure settings (GRADE 2B); we suggest implementing extracorporeal membrane oxygenation for those with severe ARDS (GRADE 2B); we suggest against using high-dose steroids (GRADE 2C); and we recommend using low-dose steroids (GRADE 1B). The recommendations for pediatric patients with ARDS are as follows: we suggest against using non-invasive respiratory support (non-invasive positive pressure ventilation/high-flow nasal cannula oxygen therapy) (GRADE 2D); we suggest placing pediatric patients with moderate ARDS in the prone position (GRADE 2D); we suggest against routinely implementing NO inhalation therapy (GRADE 2C); and we suggest against implementing daily sedation interruption for pediatric patients with respiratory failure (GRADE 2D).

CONCLUSIONS

This article is a translated summary of the full version of the ARDS Clinical Practice Guideline 2021 published in Japanese (URL: https://www.jrs.or.jp/publication/jrs_guidelines/). The original text, which was written for Japanese healthcare professionals, may include different perspectives from healthcare professionals of other countries.

Pneumococcal urinary antigen testing for antimicrobial guidance in community-acquired pneumonia: a register-based cohort study

OBJECTIVES

To evaluate the effect of pneumococcal urinary antigen test (UAT) usage on broad-spectrum antibiotic treatment in community-acquired pneumonia (CAP).

METHODS

Patients admitted to 32 Swedish hospitals between 2011-2014 were retrospectively included from the Swedish National Quality Register of CAP. Using propensity score matched data, stratified by CRB-65 score, we studied the effect of performing UAT and of positive test results on treatment with broad-spectrum β-lactam monotherapy (BSBM) and antibiotics with coverage for atypical bacteria compared to narrow-spectrum β-lactam monotherapy (NSBM).

RESULTS

UAT was performed for 4,995/14,590 (34.2%) patients, 603/4,995 (12.1%) of whom had positive test results. At day three, performing UAT was not associated with decreased use of BSBM (OR 1.07, 95% CI 0.94-1.23) but was associated with increased atypical coverage among patients with CRB-65 score 2 (OR 1.47, 95% CI 1.06-2.02). A positive UAT was associated with decreased BSBM use (OR 0.39, 95% CI 0.25-0.60) and decreased atypical coverage (OR 0.25, 95% CI 0.16-0.37), predominantly in non-severe CAP. At day one, performing UAT was associated with atypical coverage among patients with CRB-65 scores 2 (OR 2.60, 95% CI 1.69-3.98) and 3-4 (OR 3.69, 95% CI 1.55-8.79), and a positive test reduced the odds of BSBM treatment among CRB-65 score 3-4 patients (OR 3.49, 95% CI 1.02-12.0).

CONCLUSIONS

Performing UAT had no overall effect on decreasing the use of BSBM treatment by day three of hospitalization, yet non-severely ill patients with positive UAT results were less likely to be treated with BSBM and antibiotics with atypical coverage.

Urinary Antigen Testing for Respiratory Infections: Current Perspectives on Utility and Limitations

Pneumonia is a leading cause of hospitalization and death due to infection worldwide. Streptococcus pneumoniae and Legionella pneumophila remain among the most commonly identified bacterial pathogens. Unfortunately, more than half of all pneumonia cases today lack an etiologic diagnosis due to limitations in traditional microbiological methods like blood and sputum cultures, which are affected by poor sample collection, prior antibiotic administration, and delayed processing. Urinary antigen tests (UATs) for S. pneumoniae and L. pneumophila have emerged as powerful tools for improving the diagnosis of bacterial respiratory infections, enabling physicians to administer early directed therapy and improve antimicrobial stewardship. UATs are simple, rapid, and non-invasive diagnostic tests with high specificity (>90%) and moderate sensitivity (<80%). The potential impact of urinary antigen testing is especially significant for respiratory infections caused by Legionella. While all recommended community-acquired pneumonia (CAP) therapies are adequate for treating pneumococcal pneumonia, only certain antibiotics are effective against Legionella. Delayed therapy for Legionella is associated with worse clinical outcomes, which underscores the importance of rapid diagnostic methods like UATs. Despite their potential impact, current American Thoracic Society and Infectious Diseases Society of America (ATS/IDSA) guidelines argue against the routine use of urinary antigen testing for S. pneumoniae and L. pneumophila, except in patients with severe CAP and those with epidemiological risk factors for Legionella. Further research is necessary to evaluate the impact of early targeted treatment due to positive UAT results, as well as optimal strategies for UAT utilization. The purpose of this review is to summarize the UATs available for bacterial respiratory infections, describe current guidelines on their usage, and assess their impact on clinical outcomes and targeted therapy.

A positive pneumococcal urinary antigen test promotes narrow spectrum antibiotic use in patients with non-invasive pneumococcal pneumonia

BACKGROUND

We compared changes in antibiotics in patients diagnosed with noninvasive pneumococcal pneumonia (NPP) by pneumoccocal urinary antigen tests or respiratory cultures.

METHODS

We compared patients diagnosed by pneumococcal urinary antigen tests or respiratory cultures that grew Streptococcus pneumoniae. We assessed the time from sample receipt to final result and antibiotic regimens, including an Antibiotic Spectrum Index (ASI).

RESULTS

Seventy-two cases of NPP were diagnosed by pneumococcal urinary antigen and 87 by respiratory cultures, with a median time from sample receipt to final result of 0.21 days (interquartile range (IQR) 0.17-1.17) and 3.21 days (IQR 3.17-4.21 days), respectively. Among 123 cases without antibiotic allergies, between days 0 and 2, the ASI decreased in 36% (18/50) of cases diagnosed by urinary antigen compared to 10% (7/73) of cases diagnosed by respiratory culture (P < 0.01).

CONCLUSIONS

Positive pneumococcal urinary antigen tests lead to early deescalation of antibiotics more frequently than respiratory cultures.

Feasibility of a quantitative polymerase chain reaction assay for diagnosing pneumococcal pneumonia using oropharyngeal swabs

Streptococcus pneumoniae is the most important pathogen causing community-acquired pneumonia (CAP). The current diagnostic microbial standard detects S. pneumoniae in less than 30% of CAP cases. A quantitative polymerase chain reaction (PCR) targeting autolysin (lytA) is able to increase the rate of detection. The aim of this study is validation of this quantitative PCR in vitro using different available strains and in vivo using clinical samples (oropharyngeal swabs). The PCR autolysin (lytA) was validated by testing the intra- and inter-run variability. Also, the in vitro specificity and sensitivity, including the lower limit of detection was determined. In addition, a pilot-study was performed using samples from patients (n = 28) with pneumococcal pneumonia and patients (n = 28) with a pneumonia without detection of S. pneumoniae with the current diagnostic microbial standard, but with detection of either a viral and or another bacterial pathogen to validate this test further. The intra- and inter-run variability were relatively low (SD's ranging from 0.08 to 0.96 cycle thresholds). The lower limit of detection turned out to be 1-10 DNA copies/reaction. In-vitro sensitivity and specificity of the tested specimens (8 strains carrying lytA and 6 strains negative for lytA) were both 100%. In patients with pneumococcal and non-pneumococcal pneumonia a cut-off value of 6.000 copies/mL would lead to a sensitivity of 57.1% and a specificity of 85.7%. We were able to develop a quantitative PCR targeting lytA with good in-vitro test characteristics.

Urinary antigen testing in community-acquired pneumonia in adults: an update

INTRODUCTION

Community-acquired pneumonia (CAP) continues to be a leading cause of hospitalization and mortality worldwide. Streptococcus pneumoniae and Legionella pneumophila remain the major etiological agents and are responsible for a significant proportion of CAP mortality. Among diagnostic tests for CAP, urine antigen detection of S. pneumoniae and L. pneumophila is widely accepted due to the simplicity of collection and the rapidity of the test results. Areas covered: This comprehensive review outlines the urinary antigen tests available, discusses their sensitivity and specificity, and assesses the usefulness of their results as the basis for targeted therapy. Expert commentary: There have been advances in urine antigen detection tests for patients with CAP. New methodologies show greater sensitivity, detect S. pneumoniae and L. pneumophila in a single test, and also detect pneumococcal serotypes. In addition, urine antigen detection tests have shown a high specificity, which means that a positive result practically indicates the causative pathogen of CAP. Therefore, a positive result can lead to a targeted therapy that is likely to improve patient outcomes and reduce the risk of resistance and adverse events. However, well-designed studies are needed to evaluate the usefulness of urine antigen detection tests with regard to clinical outcomes.

Principles of antibiotic application in children with lobar pneumonia: Step-up or step-down

In order to provide a scientific basis for rational use of antibiotics, we studied and compared the therapeutic effects of step-down and step-up antibiotic treatment schemes in children with lobar pneumonia. Eighty cases of children with lobar pneumonia were enrolled in this study and were randomly divided into two groups: The observation group and the control group, with 40 cases in each group. In the observation group, there were 23 cases with mild and 17 cases with severe lobar pneumonia, and in the control group, 25 were mild and 15 were severe cases. Patients in the control group were treated with antibiotics using step-up therapy method, while patients in the observation group were treated using step-down antibiotic therapy. Our results showed no significant differences in white blood cell (WBC) reduction rate, the course of antibiotic treatment, disappearance time of pulmonary rales and total efficiency in children with mild lobar pneumonia in the observation group after 72 h of treatment. The level of high-sensitivity C-reactive protein (hs-CRP) and procalcitonin (PCT) in the observation group were significantly lower. After 72 h of treatment of children with severe lobar pneumonia in the observation group, the rate of WBC reduction accelerated significantly. Compared to the patients in the control group, the course of antibiotic treatment and disappearance time of pulmonary rales were shortened significantly, while the total efficiency of treatment was improved considerably in the observation group. Also in the observation group, hs-CRP and PCT levels were significantly lower than that in the control group. In severe cases, step-down therapy showed a better result in relieving the inflammatory reactions. The disappearance time of pulmonary rales and the effective rate of treatment was significantly higher than those of step-up therapy. It was obvious that for children with severe lobar pneumonia, step-down therapy produced better results in relieving the inflammatory reaction.