Rapid urine antigen testing for Streptococcus pneumoniae in adults with community-acquired pneumonia: clinical use and barriers

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.

Comparative characteristics of the background and blood test findings in adults with pneumococcal pneumonia and invasive pneumococcal disease: A retrospective study

INTRODUCTION

Invasive pneumococcal disease (IPD) is often fatal, requiring prompt diagnosis and treatment. To evaluate the factors associated with IPD in adults, we retrospectively investigated its characteristics compared to pneumococcal pneumonia without confirmation of invasion (PP).

METHODS

Patients >18 years with PP (n = 79) and IPD (n = 53) from whom Streptococcus pneumoniae was isolated were enrolled from two hospitals between 2011 and 2017. Clinical backgrounds, blood test results at admission, initial antimicrobials administered, isolate serotypes, and outcomes were compared between the PP and IPD groups.

RESULTS

Patients with IPD exhibited higher mortality (28.3%) than those with PP (2.5%) (p<0.001), regardless of the type of antimicrobials first administered. The majority (80.0%) of fatal cases of IPD were due to vaccine serotypes. Almost all patients with PP (97.4%) and IPD (88.7%) had underlying disease. C-reactive protein (CRP) ≥17.0 mg/dL (odds ratio [OR], 7.1; 95% CI, 2.7-19.0; p<0.001), white blood cell counts <11.0 × 10³/μL (OR, 3.2; 95% CI, 1.3-8.4; p = 0.016), and platelet (PLT) counts <16.2 × 10⁴/μL (OR, 2.8; 95% CI, 1.1-7.4; p = 0.036) were significantly more common in IPD. Moreover, 89.5% of cases with both CRP ≥23.8 mg/dL and PLT <18.5 × 10⁴/μL were diagnosed with IPD.

CONCLUSION

Laboratory blood test findings at admission, particularly high CRP and low PLT values, are useful early indicators of IPD in adults. These results could be used to initiate rapid and intensive treatment and improve prognosis.

Plummer M. The evolution of rapid antigen detection systems and their application for COVID-19 and other serious respiratory infectious diseases

Making the correct diagnosis of a patient seeking medical attention is the ultimate goal of a practicing physician, irrespective of whether the cause of the patient's condition is infectious or non-infectious. Antigen detection tests can be used to aid in the diagnosis of various infectious-related disorders including COVID-19 where it has become especially important due to the serious nature of this disease and its worldwide prevalence. These tests closely mimic one of the earliest prototypes - the urine pregnancy test - and as a result they have gained wide acceptance based on their overall simplicity, low cost and relative accuracy. In some situations, especially as a screening test, they can be used instead of the more technically demanding and complex molecular and serologic assays that are still useful and helpful under many different circumstances. Antigen detection systems are based on finding a particular immunogenic component, typically a protein or polysaccharide molecule, that is both unique and an integral part of the pathogen or other biological entity. Because these tests generally provide only qualitative results, they often need to be supplemented with other and sometimes more sophisticated laboratory-based diagnostic procedures to corroborate the initial test result. In this review, we first describe general background information on antigen-detection methods, including any unique aspects of their overall design, and then follow with an extensive description on the merits and limitations of these tests for detecting COVID-19 and, to a lesser extent, for other serious respiratory diseases caused by three common bacterial pathogens - Streptococcus pyogenes, Streptococcus pneumoniae and Legionella pneumophila.

Pneumococcal Urinary Antigen Testing in United States Hospitals: A Missed Opportunity for Antimicrobial Stewardship

BACKGROUND

The Infectious Diseases Society of America recommends pneumococcal urinary antigen testing (UAT) when identifying pneumococcal infection would allow for antibiotic de-escalation. However, the frequencies of UAT and subsequent antibiotic de-escalation are unknown.

METHODS

We conducted a retrospective cohort study of adult patients admitted with community-acquired or healthcare-associated pneumonia to 170 US hospitals in the Premier database from 2010 to 2015, to describe variation in UAT use, associations of UAT results with antibiotic de-escalation, and associations of de-escalation with outcomes.

RESULTS

Among 159 894 eligible admissions, 24 757 (15.5%) included UAT performed (18.4% of intensive care unit [ICU] and 15.3% of non-ICU patients). Among hospitals with ≥100 eligible patients, UAT proportions ranged from 0% to 69%. Compared to patients with negative UAT, 7.2% with positive UAT more often had a positive Streptococcus pneumoniae culture (25.4% vs 1.9%, P < .001) and less often had resistant bacteria (5.2% vs 6.8%, P < .05). Of patients initially treated with broad-spectrum antibiotics, most were still receiving broad-spectrum therapy 3 days later, but UAT-positive patients more often had coverage narrowed (38.4% vs 17.0% UAT-negative and 14.6% untested patients, P < .001). Hospital rate of UAT was strongly correlated with de-escalation following a positive test. Only 3 patients de-escalated after a positive UAT result were subsequently admitted to ICU.

CONCLUSIONS

UAT is not ordered routinely in pneumonia, even in ICU. A positive UAT result was associated with less frequent resistant organisms, but usually did not lead to antibiotic de-escalation. Increasing UAT and narrowing therapy after a positive UAT result are opportunities for improved antimicrobial stewardship.

Blind Spots of Traditional Microbiological Tests for Severe Community-Acquired Pneumonia in Adults and Availability of Nonculture Techniques: A Nationwide Survey of Physicians in China

BACKGROUND

In China, no national survey has been conducted to evaluate physicians' attitudes and compliance with guidelines in the management of adult patients with community-acquired pneumonia (CAP). Therefore, this study aimed to evaluate physicians' awareness of the use of microbiological tests in the management of severe CAP (SCAP) and to investigate the availability of nonculture tests in China.

METHODS

A nationwide electronic questionnaire survey was conducted among Chinese physicians between March and July 2018, which assessed their viewpoints concerning the issues in the management of SCAP.

RESULTS

A total of 6333 physicians completed this survey, evenly covering all career stages. Among these, 3208 (50.6%) and 1936 (30.6%) had blind spots in the application of blood and sputum cultures in the management of SCAP, respectively. Nonteaching hospital, nonrespirologists, and junior career stage were independently associated with misunderstandings. Regarding nonculture methods, 52.7% of the facilities had no access to polymerase chain reaction-based pathogen detection tests. The accessibility of urinary antigen tests for Streptococcus pneumoniae (42.5%) and Legionella pneumophila (38.5%) was also low. The main barriers were inland and remote region, lower hospital level, and nonteaching hospital.

CONCLUSIONS

Insufficient use of sputum and blood cultures, together with low accessibility of major nonculture techniques, were noticeable barriers to achieving microbiological diagnosis of SCAP in China. To help curb the overuse of broad-spectrum antibiotics, further measures should be taken to raise awareness among nonspecialists and promote rapid nonculture tests, especially in nonteaching hospitals and developing regions.

Evaluation of the pneumococcal urinary antigen test (PUT): a retrospective study

OBJECTIVES

To determine the usefulness of the pneumococcal urinary antigen test (PUT) and to describe the characteristics of pneumococcal pneumonia.

METHODS

In this retrospective study, we examined the effects of prior antibiotic treatment, pneumonia onset period, and sputum quality on the results of PUT. Clinical information was collected via medical records from all adult patients who were hospitalized at the Fujita Health University Bantane Hospital with "pneumonia" as a new diagnosis from April 2015 to March 2018.

RESULTS

A total of 482 patients with pneumonia were included, of whom 103 had pneumococcal pneumonia. The frequency of PUT positivity did not differ significantly in patients with a pneumonia onset period of ≥3 days compared with those with a period of ≤2 days (P=0.514). Patients with a history of prior antimicrobial therapy had a significantly lower rate of positive sputum culture vs those with no such history (P=0.005); however, PUT positivity in the two groups did not differ significantly (P=0.367).

CONCLUSIONS

Our results showed that urinary antigen testing for pneumococcal pneumonia is useful for diagnosis regardless of prior antibiotic treatment and time since symptom onset.

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.

Rapid Streptococcus Pneumonia Antigen Detection on Postmortem Urine in a Death Due to Pneumococcal Meningitis

Streptococcus pneumoniae is the leading cause of adult bacterial meningitis. Differing from Neisseria meningitidis (the second most common cause of acute bacterial meningitis), contact tracing and chemoprophylaxis are not required. At postmortem, the differentiation between S. pneumoniae and N. meningitidis is traditionally done by culture and polymerase chain reaction performed on blood or cerebrospinal fluid, but may take hours, if not days, to analyze. We present a death from bacterial meningitis in a 73-year-old woman in which a rapid urinary pneumococcal antigen testing was able to identify S. pneumoniae as the causative organism within 1 hour. This was confirmed by subsequent brain swab culture. The rapid urinary pneumococcal antigen test in the case prevented the need for contact tracing and chemoprophylaxis. This case highlights the potential use of this test to rapidly identify the culprit organism at postmortem examination when acute bacterial meningitis is detected.

Streptococcus pneumoniae's Virulence and Host Immunity: Aging, Diagnostics, and Prevention

Streptococcus pneumoniae is an infectious pathogen responsible for millions of deaths worldwide. Diseases caused by this bacterium are classified as pneumococcal diseases. This pathogen colonizes the nasopharynx of its host asymptomatically, but overtime can migrate to sterile tissues and organs and cause infections. Pneumonia is currently the most common pneumococcal disease. Pneumococcal pneumonia is a global health concern and vastly affects children under the age of five as well as the elderly and individuals with pre-existing health conditions. S. pneumoniae has a large selection of virulence factors that promote adherence, invasion of host tissues, and allows it to escape host immune defenses. A clear understanding of S. pneumoniae's virulence factors, host immune responses, and examining the current techniques available for diagnosis, treatment, and disease prevention will allow for better regulation of the pathogen and its diseases. In terms of disease prevention, other considerations must include the effects of age on responses to vaccines and vaccine efficacy. Ongoing work aims to improve on current vaccination paradigms by including the use of serotype-independent vaccines, such as protein and whole cell vaccines. Extending our knowledge of the biology of, and associated host immune response to S. pneumoniae is paramount for our improvement of pneumococcal disease diagnosis, treatment, and improvement of patient outlook.

Serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae isolates from adult patients in Jakarta, Indonesia

Currently, the data on pneumococcal invasive disease in the Indonesian population are limited. In this study, we investigated the serotype distribution and antimicrobial susceptibility of Streptococcus pneumoniae. These samples were isolated from the sputum of adult patients with non-specific clinical symptoms aged 18-87 years in Jakarta, Indonesia, from August to October 2014. Of the 349 sputum specimens, thirteen isolates were identified as S. pneumoniae strains (4%), with two strains each for serotype 19F, 3, and 15A, and one strain each for serotype/serogroup 13, 23A, 6, 34, 17F, 16F, and untypeable. Resistance to tetracycline was most common with only 5 of 13 strains being susceptible. In conclusion, these data provide an initial in the surveillance of invasive pneumococcus in the Indonesia population.

Influence of Antibiotics on the Detection of Bacteria by Culture-Based and Culture-Independent Diagnostic Tests in Patients Hospitalized With Community-Acquired Pneumonia

BACKGROUND

Specimens collected after antibiotic exposure may reduce culture-based bacterial detections. The impact on culture-independent diagnostic tests is unclear. We assessed the effect of antibiotic exposure on both of these test results among patients hospitalized with community-acquired pneumonia (CAP).

METHODS

Culture-based bacterial testing included blood cultures and high-quality sputum or endotracheal tube (ET) aspirates; culture-independent testing included urinary antigen testing (adults) for Streptococcus pneumoniae and Legionella pneumophila and polymerase chain reaction (PCR) on nasopharyngeal and oropharyngeal (NP/OP) swabs for Mycoplasma pneumoniae and Chlamydia pneumoniae. The proportion of bacterial detections was compared between specimens collected before and after either any antibiotic exposure (prehospital and/or inpatient) or only prehospital antibiotics and increasing time after initiation of inpatient antibiotics.

RESULTS

Of 4678 CAP patients, 4383 (94%) received antibiotics: 3712 (85%) only inpatient, 642 (15%) both inpatient and prehospital, and 29 (<1%) only prehospital. There were more bacterial detections in specimens collected before antibiotics for blood cultures (5.2% vs 2.6%; P < .01) and sputum/ET cultures (50.0% vs 26.8%; P < .01) but not urine antigen (7.0% vs 5.7%; P = .53) or NP/OP PCR (6.7% vs 5.4%; P = .31). For all diagnostic testing, bacterial detections declined with increasing time between inpatient antibiotic administration and specimen collection.

CONCLUSIONS

Bacteria were less frequently detected in culture-based tests collected after antibiotics and in culture-independent tests that had longer intervals between antibiotic exposure and specimen collection. Bacterial yield could improve if specimens were collected promptly, preferably before antibiotics, providing data for improved antibiotic selection.

Evaluating the utility of Binax NOW Streptococcus pneumoniae urinary antigen test in adults with community acquired pneumonia in China

INTRODUCTION

Binax NOW rapid immunochromatographic membrane test (ICT), a rapid method for detection of Streptococcus pneumoniae antigen, has been used widely in Europe and America, but rarely in China.

OBJECTIVE

Our aim is to evaluate the utility of the ICT among adult patients with community acquired pneumonia (CAP) in China.

METHODS

Adult patients with CAP were prospectively recruited from 12 general hospitals. ICT tests were done in all patients and clinical data were recorded. Qualified sputum culture was used as the standard for determining the diagnostic usefulness of ICT test.

RESULT

Thousand hundred fifty four CAP patients were enrolled in analysis, with median (IQR) age of 48 (35) years. 276 (23.9%) patients had underling diseases, 770 (66.7%) had received antibiotics before ICT test. Overall, the positive rate of ICT test was 3.3%, with sensitivity and specificity 57.9% and 96.6%, respectively. Disease severity, chronic obstructive pulmonary disease (COPD), increased age; respiratory rate (RR), neutrophil ratio, blood urea nitrogen (BUN), procalcitonin (PCT) and the decreased oxygenation index were associated with positive results of ICT tests. Patients with BUN >7 mmol/L, CURB-65 3-5, PCT > 2ng/mL were the top three groups with highest positive rate of ICT test (22.6%, 22.2% and 21.1% respectively).

CONCLUSION

ICT test has a moderate sensitivity and high specificity in adults with CAP in China. Patients classified as sever pneumonia, or those with BUN > 7 mmol/L, or PCT > 2 ng/mL are more likely to have positive results.

Usefulness of pneumococcal antigen urinary testing in the intensive care unit?

OBJECTIVES

The use of pneumococcal antigen urinary tests is substantially increasing and is associated with a significant cost. The relevant use of this test in the intensive care unit (ICU) should be better defined. Our aim was to define the role of this test in relation to other microbiological tests. We described a series of patients admitted to the ICU for an invasive pneumococcal disease (IPD).

PATIENTS AND METHODS

We conducted a retrospective and descriptive study of the microbiological tests used to diagnose IPD in patients admitted to the ICU of the University Hospital in Bordeaux. Our aim was to measure the sensitivity of these bacteriological tests and of the BinaxNOWS. pneumoniae test.

RESULTS

Between 2009 and 2013, 148 patients were admitted for an IPD. A lower respiratory tract infection was diagnosed in 96.6% of them (143 patients). The overall ICU case fatality rate was 17.6%. The sensitivity of the pneumococcal antigen urinary test, sputum bacteriological examination, and blood cultures was respectively 83%, 37.6%, and 29.7%. S. pneumoniae was isolated from at least one bacteriological sample in 48.6% of patients, but in 51.4%, the diagnosis was only based on the results of the pneumococcal antigen urinary test.

CONCLUSION

We suggest performing a pneumococcal antigen urinary test when an IPD is suspected, only if the bacteriological tests are still negative after 48hours. This strategy would result in a substantial cost saving. Patients would not face any additional risks as the result of the pneumococcal antigen urinary test does not have any impact on the initially prescribed antibiotic therapy.

[Urine antigen testing: Indication and contribution to the treatment of community-acquired pneumonia]

Urinary antigen tests are quick and simple tests helping to provide an etiological diagnosis in community-acquired pneumonia. However, their prescription is sometimes excessive and performed in unjustified situations. The therapeutic benefit is limited. Indeed, studies show that appropriate antibiotic therapy based on the result of urinary antigen tests does not improve the cost and the patient survival compared to empirical antibiotic therapy. One must be careful before antibiotic therapy reduction based on the sole negative result of urinary antigen test. Legionella urinary antigen test is the most commonly method used for the diagnosis of legionellosis but must be prescribed in a specific clinical context. Streptococcus pneumoniae urinary antigen test is especially interesting in the epidemiological surveillance of pneumococcal community-acquired pneumonia.

Hepatitis C Management and the Infectious Diseases Physician: A Survey of Current and Anticipated Practice Patterns

This query of North American infectious diseases physicians reviews current and anticipated practice patterns related to hepatitis C virus (HCV) care. Less than 20% of survey respondents evaluated and/or treated >10 HCV-infected individuals in the past year. We review HCV practice patterns, barriers to management, and education among infectious diseases physicians.