Rapid urinary antigen test for diagnosis of pneumococcal community-acquired pneumonia in adults

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.

Identification of Potential Urinary Metabolite Biomarkers of Pseudomonas aeruginosa Ventilator-Associated Pneumonia

Introduction:

Ventilator-associated pneumonia (VAP) caused by Pseudomonas aeruginosa is a major cause of morbidity and mortality in hospital intensive care units (ICU). Rapid identification of P. aeruginosa-derived markers in easily accessible patients’ samples can enable an early detection of P. aeruginosa VAP (VAP-PA), thereby stewarding antibiotic use and improving clinical outcomes.

Methods:

Metabolites were analysed using liquid chromatography-mass spectrometry (LC-MS) in prospectively collected urine samples from mechanically ventilated patients admitted to the Antwerp University Hospital ICU. Patients were followed from the start of mechanical ventilation (n = 100 patients) till the time of clinical diagnosis of VAP (n = 13). Patients (n = 8) in whom diagnosis of VAP was further confirmed by culturing respiratory samples and urine samples were studied for semi-quantitative metabolomics.

Results:

We first show that multivariate analyses highly discriminated VAP-PA from VAP–non-PA as well as from the pre-infection groups (R² = .97 and .98, respectively). A further univariate analysis identified 58 metabolites that were significantly elevated or uniquely present in VAP-PA compared to the VAP–non-PA and pre-infection groups (P < .05). These comprised both a known metabolite of histidine as well as a novel nicotine metabolite. Most interestingly, we identified 3 metabolites that were not only highly upregulated for, but were also highly specific to, VAP-PA, as these metabolites were completely absent in all pre-infection timepoints and in VAP–non-PA group.

Conclusions:

Considerable differences exist between urine metabolites in VAP-PA compared to VAP due to other bacterial aetiologies as well to non-VAP (pre-infection) timepoints. The unique urinary metabolic biomarkers we describe here, if further validated, could serve as highly specific diagnostic biomarkers of VAP-PA.

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.

Non-bacteremic pneumococcal pneumonia: general characteristics and early predictive factors for poor outcome

Purpose: Nowadays, most cases of pneumococcal community-acquired pneumonia (PCAP) are diagnosed by positive urinary antigen. Our aims were to analyse process of care in patients hospitalised with non-bacteremic PCAP (NB-PCAP) and identify factors associated with poor outcome (PO) in this population.Methods: We conducted a prospective study, including patients hospitalised for NB-PCAP (positive urinary antigen and negative blood culture) over a 15 year period. We performed multivariate analysis of predisposing factors for PO, defined as need for mechanical ventilation and/or shock and/or in-hospital death.Results: Of the 638 patients included, 4.1% died in hospital and 12.8% had PO. Host-related factors were similar in patients with and without PO, but patients with PO had higher illness severity on admission. Adjusted analysis revealed the following independent factors associated with PO: being a nursing home resident (OR: 6.156; 95% CI: 1.827-20.750; p = .003), respiratory rate ≥30 breaths/min (OR: 3.030; 95% CI: 1.554-5.910; p = .001), systolic blood pressure <90 mmHg (OR: 4.789; 95% CI: 1.967-11.660; p = .001), diastolic blood pressure <60 mmHg (OR: 2.820; 95% CI: 1.329-5.986; p = .007), pulse rate ≥125 beats/min (OR: 3.476; 95% CI: 1.607-7.518; p = .002), pH <7.35 (OR: 9.323; 95% CI: 3.680-23.622; p < .001), leukocytes <4000/µL (OR: 10.007; 95% CI: 2.960-33.835; p < .001), and severe inflammation (OR: 2.364; 95% CI 1.234-4.526; p = .009). The area under the curve for predicting PO was 0.890 (95% CI: 0.851-0.929).Conclusions: Since patients with PO seem different and had worse in-hospital course, we identified eight independent risk factors for PO measurable on admission.

The Use of Inappropriate Antibiotics in Patients Admitted to Intensive Care Units with Nursing Home-Acquired Pneumonia at a Korean Teaching Hospital

Background

Use of appropriate antibiotics for the treatment of pneumonia is integral in patients admitted to intensive care units (ICUs). Although it is recommended that empirical treatment regimens should be based on the local distribution of pathogens in patients with suspected hospital-acquired pneumonia, few studies observe patients admitted to ICUs with nursing home–acquired pneumonia (NHAP). We found factors associated with the use of inappropriate antibiotics in patients with pneumonia admitted to the ICU via the emergency room (ER).

Methods

We performed a retrospective cohort study of 83 pneumonia patients with confirmed causative bacteria admitted to ICUs via ER March 2015–May 2017. We compared clinical parameters, between patients who received appropriate or inappropriate antibiotics using the Mann-Whitney U, Pearson's chi-square, and Fisher's exact tests. We investigated independent factors associated with inappropriate antibiotic use in patients using multivariate logistic regression.

Results

Among 83 patients, 30 patients (36.1%) received inappropriate antibiotics. NHAP patients were more frequently treated with inappropriate antibiotics than with appropriate antibiotics (47.2% vs. 96.7%, p<0.001). Methicillin-resistant Staphylococcus aureus was more frequently isolated from individuals in the inappropriate antibiotics–treated group than in the appropriate antibiotics–treated group (7.5% vs. 70.0%, p<0.001). In multivariate analysis, NHAP was independently associated with the use of inappropriate antibiotics in patients with pneumonia admitted to the ICU via ER.

Conclusion

NHAP is a risk factor associated with the use of inappropriate antibiotics in patients with pneumonia admitted to the ICU via the ER.

Evaluation of the Sofia S. pneumoniae FIA for Detection of Pneumococcal Antigen in Patients with Bloodstream Infection

The usefulness of pneumococcal urinary antigen tests (UATs) in severe pneumococcal infection relies heavily on the performance in bacteremic patients. Fluorescence technology and automatic reading of test results may improve UAT performance. We evaluated the automatically read Sofia S. pneumoniae FIA for diagnosing pneumococcal bloodstream infection (BSI) in hospitalized adult patients. First, the Sofia FIA was evaluated on 97 patients with pneumococcal (n = 47) and nonpneumococcal (n = 50) BSI and compared with results by the visually read BinaxNOW S. pneumoniae immunochromatographic test (ICT) and ImmuView S. pneumoniae and Legionella pneumophila ICT. In four cases (4.1%), the Sofia FIA showed invalid test results, three of which showed invalid results by the ImmuView ICT previously. Based on 93 valid cases, the Sofia FIA showed similar sensitivity (for both comparisons: 68% versus 62%; P = 0.45) and specificity (for both comparisons: 91% versus 93%; P = 1.00) as the visually read UATs. Second, the Sofia FIA was prospectively evaluated on 82 consecutive nonfrozen urine samples, detecting pneumococcal antigen in 10 of 14 (sensitivity, 71%) pneumococcal BSI patients, similarly to the visually and automatically read BinaxNOW ICT (both 12 of 14; sensitivity, 86%; P = 0.50). Of five nonpneumococcal BSI cases, the Sofia FIA showed an invalid test result in one case, but no positive UAT results were obtained. Thus, the sensitivity and specificity of the Sofia FIA were similar to the performance rates of other UATs in patients with BSI, but invalid test results are of concern for the usefulness in pneumococcal BSI.

Pathogenesis and prevention of risk of cardiovascular events in patients with pneumococcal community-acquired pneumonia

It is now well recognized that cardiovascular events (CVE) occur quite commonly, both in the acute phase and in the long-term, in patients with community-acquired pneumonia (CAP). CVE have been noted in up to 30% of patients hospitalized with all-cause CAP. One systematic review and meta-analysis of hospitalized patients with all-cause CAP noted that the incidence rates for overall cardiac events were 17.7%, for incident heart failure were 14.1%, for acute coronary syndromes were 5.3% and for incident cardiac arrhythmias were 4.7%. In the case of pneumococcal CAP, almost 20% of patients studied had one or more of these cardiac events. Recent research has provided insights into the pathogenesis of the acute cardiac events occurring in pneumococcal infections. With respect to the former, key involvements of the major pneumococcal protein virulence factor, pneumolysin, are now well documented, whilst systemic platelet-driven neutrophil activation may also contribute. However, events involved in the pathogenesis of the long-term cardiovascular sequelae remain largely unexplored. Emerging evidence suggests that persistent antigenaemia may predispose to the development of a systemic pro-inflammatory/prothrombotic phenotype underpinning the risk of future cardiovascular events. The current manuscript briefly reviews the occurrence of cardiovascular events in patients with all-cause CAP, as well as in pneumococcal and influenza infections. It highlights the close interaction between influenza and pneumococcal pneumonia. It also includes a brief discussion of mechanisms of the acute cardiac events in CAP. However, the primary focus is on the prevalence, pathogenesis and prevention of the longer-term cardiac sequelae of severe pneumococcal disease, particularly in the context of persistent antigenaemia and associated inflammation.

Pneumococcal pneumonia prevalence among adults with severe acute respiratory illness in Thailand - comparison of Bayesian latent class modeling and conventional analysis

BACKGROUND

Determining the etiology of pneumonia is essential to guide public health interventions. Diagnostic test results, including from polymerase chain reaction (PCR) assays of upper respiratory tract specimens, have been used to estimate prevalence of pneumococcal pneumonia. However limitations in test sensitivity and specificity and the specimen types available make establishing a definitive diagnosis challenging. Prevalence estimates for pneumococcal pneumonia could be biased in the absence of a true gold standard reference test for detecting Streptococcus pneumoniae.

METHODS

We conducted a case control study to identify etiologies of community acquired pneumonia (CAP) from April 2014 through August 2015 in Thailand. We estimated the prevalence of pneumococcal pneumonia among adults hospitalized for CAP using Bayesian latent class models (BLCMs) incorporating results of real-time polymerase chain reaction (qPCR) testing of upper respiratory tract specimens and a urine antigen test (UAT) from cases and controls. We compared the prevalence estimate to conventional analyses using only UAT as a reference test.

RESULTS

The estimated prevalence of pneumococcal pneumonia was 8% (95% CI: 5-11%) by conventional analyses. By BLCM, we estimated the prevalence to be 10% (95% CrI: 7-16%) using binary qPCR and UAT results, and 11% (95% CrI: 7-17%) using binary UAT results and qPCR cycle threshold (Ct) values.

CONCLUSIONS

BLCM suggests a > 25% higher prevalence of pneumococcal pneumonia than estimated by a conventional approach assuming UAT as a gold standard reference test. Higher quantities of pneumococcal DNA in the upper respiratory tract were associated with pneumococcal pneumonia in adults but the addition of a second specific pneumococcal test was required to accurately estimate disease status and prevalence. By incorporating the inherent uncertainty of diagnostic tests, BLCM can obtain more reliable estimates of disease status and improve understanding of underlying etiology.

Decreased relative risk of pneumococcal pneumonia during the last decade, a nested case-control study

Background

Streptococcus pneumoniae (SP) is one of the most common pathogens of Community-Acquired Pneumonia (CAP), but recent reports suggest that its incidence may be declining in relation to the use of the conjugate 13-valent pneumococcal vaccine in children. We compared the result of the immunochromatographic SP urinary antigen test (SPUAT) and clinical outcomes in patients with CAP admitted in two periods of time: 2001–2002(CAP1) and 2015–2016(CAP2).

Methods

This was a matched nested case-control study of two prospectively recorded cohorts of patients admitted with CAP, with SPUAT and blood culture performed in all patients. CAP2 cases and CAP1 controls were matched for age ± 4 years, sex, and Pneumonia Severity Index (PSI) score ± 10 points. Odds ratios (OR) for having SPUAT positive was estimated by conditional logistic regression. A multivariate model assessed the contribution of individual variables.

Results

Four hundred ninety-eight patients were recruited; 307 during the CAP1 and 191 during the CAP2 periods. Comparing both periods we observed differences, in age, PSI score, and the percentage of smokers, outpatients, previously immunized with pneumococcal vaccine, and positive SPUAT. On the other hand, mortality, admission from nursing homes, pneumococcal bacteremia and hospital admission were not different. After matching, pneumonia due to SP per the SPUAT was observed in 34(23.4%) of CAP1 and in 12(8.3%) of CAP2 patients (p < 0.001), and 6/145 CAP1 vs 33/145 CAP2 patients had received pneumococcal immunization before their admission (p < 0.001). A multivariate analysis confirmed that, independent of falling into PSI class 5, having not received the pneumococcal vaccine and having not survived the episode of pneumonia, there were two factors that increased the probability of having SPUAT positive: developing pneumonia during the CAP1 period (OR = 1.23) and having pneumococcal bacteremia (OR = 2.66).

Conclusion

We observed a reduction of the role of SP as pathogen, along with an increase in the number of patients who received pneumococcal immunization before admission, in 2015-2016 compared to 2001-2002. In addition, the use of conjugate 13-valent vaccine, starting in 2012 for childhood immunization, could be an additional factor contributing to these changes, as a result of early herd immunity in adults pneumonia.

Management of community-acquired pneumonia in immunocompetent adults: updated Swedish guidelines 2017

Based on expert group work, Swedish recommendations for the management of community-acquired pneumonia in adults are here updated. The management of sepsis-induced hypotension is addressed in detail, including monitoring and parenteral therapy. The importance of respiratory support in cases of acute respiratory failure is emphasized. Treatment with high-flow oxygen and non-invasive ventilation is recommended. The use of statins or steroids in general therapy is not found to be fully supported by evidence. In the management of pleural infection, new data show favourable effects of tissue plasminogen activator and deoxyribonuclease installation. Detailed recommendations for the vaccination of risk groups are afforded.

Invasive Disease vs Urinary Antigen-Confirmed Pneumococcal Community-Acquired Pneumonia

BACKGROUND

The burden of pneumococcal disease is measured only through patients with invasive pneumococcal disease. The urinary antigen test (UAT) for pneumococcus has exhibited high sensitivity and specificity. We aimed to compare the pneumococcal pneumonias diagnosed as invasive disease with pneumococcal pneumonias defined by UAT results.

METHODS

A prospective observational study of consecutive nonimmunosuppressed patients with community-acquired pneumonia was performed from January 2000 to December 2014. Patients were stratified into two groups: invasive pneumococcal pneumonia (IPP) defined as a positive blood culture or pleural fluid culture result and noninvasive pneumococcal pneumonia (NIPP) defined as a positive UAT result with negative blood or pleural fluid culture result.

RESULTS

We analyzed 779 patients (15%) of 5,132, where 361 (46%) had IPP and 418 (54%) had NIPP. Compared with the patients with IPP, those with NIPP presented more frequent chronic pulmonary disease and received previous antibiotics more frequently. Patients with IPP presented more severe community-acquired pneumonia, higher levels of inflammatory markers, and worse oxygenation at admission; more pulmonary complications; greater extrapulmonary complications; longer time to clinical stability; and longer length of hospital stay compared with the NIPP group. Age, chronic liver disease, mechanical ventilation, and acute renal failure were independent risk factors for 30-day crude mortality. Neither IPP nor NIPP was an independent risk factor for 30-day mortality.

CONCLUSIONS

A high percentage of confirmed pneumococcal pneumonia is diagnosed by UAT. Despite differences in clinical characteristics and outcomes, IPP is not an independent risk factor for 30-day mortality compared with NIPP, reinforcing the importance of NIPP for pneumococcal pneumonia.

Sensitivity, Specificity, and Positivity Predictors of the Pneumococcal Urinary Antigen Test in Community-Acquired Pneumonia

RATIONALE

Detection of the C-polysaccharide of Streptococcus pneumoniae in urine by an immune-chromatographic test is increasingly used to evaluate patients with community-acquired pneumonia.

OBJECTIVES

We assessed the sensitivity and specificity of this test in the largest series of cases to date and used logistic regression models to determine predictors of positivity in patients hospitalized with community-acquired pneumonia.

METHODS

We performed a multicenter, prospective, observational study of 4,374 patients hospitalized with community-acquired pneumonia.

MEASUREMENTS AND MAIN RESULTS

The urinary antigen test was done in 3,874 cases. Pneumococcal infection was diagnosed in 916 cases (21%); 653 (71%) of these cases were diagnosed exclusively by the urinary antigen test. Sensitivity and specificity were 60 and 99.7%, respectively. Predictors of urinary antigen positivity were female sex; heart rate≥125 bpm, systolic blood pressure<90 mm Hg, and SaO2<90%; absence of antibiotic treatment; pleuritic chest pain; chills; pleural effusion; and blood urea nitrogen≥30 mg/dl. With at least six of all these predictors present, the probability of positivity was 52%. With only one factor present, the probability was only 12%.

CONCLUSIONS

The urinary antigen test is a method with good sensitivity and excellent specificity in diagnosing pneumococcal pneumonia, and its use greatly increased the recognition of community-acquired pneumonia due to S. pneumoniae. With a specificity of 99.7%, this test could be used to direct simplified antibiotic therapy, thereby avoiding excess costs and risk for bacterial resistance that result from broad-spectrum antibiotics. We also identified predictors of positivity that could increase suspicion for pneumococcal infection or avoid the unnecessary use of this test.

Evaluation of urine pneumococcal antigen test performance among adults in Western Kenya

When used in an area of rural western Kenya, the BinaxNOW® urine antigen test had a sensitivity of 67% (95% Confidence Interval [CI]: 43-85%) among 21 adults ≥15 years old with acute respiratory illnesses and pneumococcal bacteremia and a specificity of 98% (95% CI: 96-99%) among 660 adults ≥15 years old without fever or cough. The specificity of the test was not significantly affected by pneumococcal colonization, regardless of patients' HIV status, age, or sex. Use of the pneumococcal urine antigen test in clinical assessments of adults in Africa with acute respiratory illness is a viable option regardless of whether a patient is colonized by pneumococci, even among HIV-infected adults, although the moderate sensitivity of the urine antigen test indicates that the test is probably best used clinically as part of a panel with other tests that can detect pneumococci.

A cohort study of the impact and acquisition of naspharyngeal carriage of Streptococcus pneumoniae during the Hajj

BACKGROUND

The annual Muslim pilgrimage attracts over two million pilgrims who gather in a limited time and space. The pilgrimage carries the potential risk of increase risk of the acquisition of Streptococcus pneumonia. In this cohort study, we evaluate the effect of the Hajj on the prevalence of pneumococcal serotype nasopharyngeal carriage in the Hajj pilgrim population. The secondary objective is to evaluate the effects of the mass gathering on carriage of invasive pneumococcal serotypes.

METHODS

This is a prospective cohort study with two data collection periods: at the beginning and at the end of the Hajj. Nasopharyngeal samples were taken via a standardized swabbing method.

RESULTS

A total of 1175 pilgrims were enrolled at the beginning of the study and 1155 (98.3%) were included at the second part of the study. The pre-Hajj samples were obtained at a mean of 0 days and the post-Hajj sampling occurred at a mean of 15 days after arrival to Saudi Arabia. The overall carriage rate of Streptococcus pneumoniae in the pre- and post-Hajj was 1.8% and 7.1% (P = 0.0016). The potential coverage of the 7-valent pneumococcal conjugate vaccine (PCV7), PCV10 and PCV13 were 15.5%, 19.1%; and 35.5%, respectively. The coverage for the 23-valent pneumococcal polysaccharide vaccine (PPV23) was 40%.

CONCLUSION

Although there was an increase in the acquisition of S. pneumoniae, its magnitude is low which does not support public health recommendations for general pneumococcal vaccination of pilgrims except those at risk.

Evaluation of the BinaxNOW® Streptococcus pneumoniae antigen test on fresh, frozen and concentrated urine samples in elderly patients with and without community-acquired pneumonia

We evaluated the BinaxNOW® urine antigen test in elderly. For fresh un-concentrated urine samples, the sensitivity for pneumococcal pneumonia was 63% and specificity 97%. After freezing and concentration, the results comparable to positive control line in intensity at 60 min gave high sensitivity (81%) with no loss in specificity (96%).

Incidence of Pneumococcal Pneumonia Among Adults in Rural Thailand, 2006-2011: Implications for Pneumococcal Vaccine Considerations

The incidence of pneumococcal pneumonia among adults is a key driver for the cost-effectiveness of pneumococcal conjugate vaccine used among children. We sought to obtain more accurate incidence estimates among adults by including results of pneumococcal urine antigen testing (UAT) from population-based pneumonia surveillance in two Thai provinces. Active surveillance from 2006 to 2011 identified acute lower respiratory infection (ALRI)-related hospital admissions. Adult cases of pneumococcal pneumonia were defined as hospitalized ALRI patients aged ≥ 18 years with isolation of Streptococcus pneumoniae from blood or with positive UAT. Among 39,525 adult ALRI patients, we identified 481 pneumococcal pneumonia cases (105 by blood culture, 376 by UAT only). Estimated incidence of pneumococcal pneumonia hospitalizations was 30.5 cases per 100,000 persons per year (2.2 and 28.3 cases per 100,000 persons per year by blood culture and UAT, respectively). Incidence varied between 22.7 in 2007 and 43.5 in 2010, and increased with age to over 150 per 100,000 persons per year among persons aged ≥ 70 years. Viral coinfections including influenza A/B, respiratory syncytial virus (RSV), and adenovirus occurred in 11% (44/409) of pneumococcal pneumonia cases tested. Use of UAT to identify cases of pneumococcal pneumonia among adults in rural Thailand substantially increases estimates of pneumococcal pneumonia burden, thereby informing cost-effectiveness analyses and vaccine policy decisions.

[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.

The Uni-Gold™ Streptococcus pneumoniae urinary antigen test: an interassay comparison with the BinaxNOW® Streptococcus pneumoniae test on consecutive urine samples and evaluation on patients with bacteremia

The performance of the recently commercialized Uni-Gold™ Streptococcus pneumoniae test for the detection of pneumococcal antigen in urine was studied in a multicenter study. First, we studied the interassay agreement between Uni-Gold™ and the BinaxNOW® S. pneumoniae urinary antigen test on 337 consecutive urine samples sent to the laboratory for the detection of pneumococcal antigen. The two tests performed similarly (κ = 0.82): both tests positive in 27 cases, both tests negative in 299 cases, and with divergent test results in 11 cases. Secondly, the tests were run on urine samples from 203 patients with bacteremia, including 51 patients with pneumococcal bacteremia. The sensitivities and specificities were 67 and 86 % for Uni-Gold™, and 57 % and 94 % for BinaxNOW®, respectively. The false-positivity rate was significantly higher for Uni-Gold™ compared with BinaxNOW® in patients with Escherichia coli bacteremia (15 vs. 2.1 %, p = 0.04), and tended to be higher in patients with bacteremia with alpha-hemolytic streptococci (32 vs. 11 %, p = 0.13). When cases with E. coli and alpha-hemolytic streptococci were excluded from the analysis, the overall false-positivity rate was 9/85 (11 %) for Uni-Gold™ and 6/85 (7.1 %) for BinaxNOW®. In conclusion, the study showed that Uni-Gold™ was not inferior to BinaxNOW® for the detection of pneumococcal urinary antigen in patients with pneumococcal bacteremia. The specificity of Uni-Gold™ was suboptimal due to false-positive results in cases with E. coli and alpha-hemolytic streptococci bacteremia. However, in patient populations usually subjected to testing for pneumococcal urinary antigen, such as pneumonia and meningitis patients, bacteremia with these pathogens is uncommon. The diagnostic usefulness of the Uni-Gold™ test should be further evaluated.

Sensitivity and specificity of the Streptococcus pneumoniae urinary antigen test for unconcentrated urine from adult patients with pneumonia: a meta-analysis

Studies on the sensitivity and specificity of the Binax Now Streptococcus pneumonia urinary antigen test (index test) show considerable variance of results. Those written in English provided sufficient original data to evaluate the sensitivity and specificity of the index test using unconcentrated urine to identify S. pneumoniae infection in adults with pneumonia. Reference tests were conducted with at least one culture and/or smear. We estimated sensitivity and two specificities. One was the specificity evaluated using only patients with pneumonia of identified other aetiologies ('specificity (other)'). The other was the specificity evaluated based on both patients with pneumonia of unknown aetiology and those with pneumonia of other aetiologies ('specificity (unknown and other)') using a fixed model for meta-analysis. We found 10 articles involving 2315 patients. The analysis of 10 studies involving 399 patients yielded a pooled sensitivity of 0.75 (95% confidence interval: 0.71-0.79) without heterogeneity or publication bias. The analysis of six studies involving 258 patients yielded a pooled specificity (other) of 0.95 (95% confidence interval: 0.92-0.98) without no heterogeneity or publication bias. We attempted to conduct a meta-analysis with the 10 studies involving 1916 patients to estimate specificity (unknown and other), but it remained unclear due to moderate heterogeneity and possible publication bias. In our meta-analysis, sensitivity of the index test was moderate and specificity (other) was high; however, the specificity (unknown and other) remained unclear.

[Which samples to obtain in the emergency department for the microbiological diagnosis of community-acquired pneumonia in the immunocompetent patient?]

Current diagnostic methods allow microbial identification in 50% of patients admitted with severe community-acquired pneumonia (CAP). Guidelines derived from epidemiological data help physicians to start empirical antimicrobial therapy. Definitive microbial diagnosis is useful to guide further pathogen-directed therapy. Blood cultures, cultures of respiratory specimens and urine antigen tests are recommended to determine the causative bacterial pathogen. Positive blood cultures range from 15 to 25% of CAP patients according to severity. Whether sputum specimens represent or not lower respiratory secretions determines its accuracy in CAP microbial diagnosis. In intubated patients, endotracheal aspirates are often of interest. Detection of positive pneumococcal or legionella urinary antigen is often associated with CAP severity. The sensitivity of this test is not decreased in patients who have received antibiotics prior to sampling. Viral pneumonia account for 10 to 40% of severe CAP. Nasal swabs are recommended for influenza identification using polymerase chain reaction (PCR) in order to deliver oseltamivir treatment. In the emergency department, atypical pneumonia serology is less useful than respiratory specimens obtained using fiberoptic bronchoscopy. Serum PCR to diagnose bacterial CAP is not superior to the other usual methods.

Streptococcus pneumoniae antigen in urine: diagnostic usefulness and impact on outcome of bacteraemic pneumococcal pneumonia in a large series of adult patients

BACKGROUND AND OBJECTIVE

Urinary pneumococcal antigen detection provides good results in the diagnosis of pneumococcal pneumonia but has rarely been used in bacteraemic pneumococcal pneumonia and it is not known whether it is associated with outcome in this type of pneumonia. Our objectives were to assess the usefulness of an immunochromatographic technique for detecting the pneumococcal antigen in urine in a large prospective study of patients with bacteraemic pneumococcal pneumonia and explore any potential association with outcomes.

METHODS

This study, carried out over 8 years, included all adult immunocompetent patients admitted for bacteraemic pneumococcal pneumonia. An immunochromatographic test for the Streptococcus pneumoniae antigen in urine was performed in the first 24 h. The sensitivity of test was assessed and patients were divided into two groups according to test results to explore differences on admission and during the course of the illness using logistic regression models.

RESULTS

Of the 350 patients with bacteraemic pneumococcal pneumonia included, 261 (74.6%) were positive for the antigen. Patient characteristics were very similar on admission and differences in severity (Pneumonia Severity Index) were not statistically significant. In the adjusted analysis, antigen-positive patients had a higher risk of intensive care unit admission, treatment failure and adverse outcome.

CONCLUSIONS

The sensitivity of the immunochromatographic urinary antigen test was 74.6% and positive results were associated with poorer clinical outcome. We therefore recommend systematic use of this test when pneumonia is diagnosed in the emergency department.

Urine antigen tests for the diagnosis of respiratory infections: legionellosis, histoplasmosis, pneumococcal pneumonia

Urinary antigen testing has grown in popularity for several significant respiratory infections, particularly Legionella pneumophila, Streptococcus pneumoniae, and Histoplasma capsulatum. By capitalizing on the concentration of shed antigen from a variety of pathogens in the kidneys for excretion in the urine, urinary antigen testing can be used to obtain rapid test results related to respiratory infection, independent of an invasive collection such as a bronchoalveolar lavage. This article describes the 3 aforementioned organisms, their role in respiratory disease, and the current status of urinary antigen testing in their respective diagnosis.

Diagnosis of pneumococcal pneumonia: current pitfalls and the way forward

Streptococcus pneumoniae is the most common cause of community-acquired pneumonia. However, it can also asymptomatically colonize the upper respiratory tract. Because of the need to distinguish between S. pneumoniae that is simply colonizing the upper respiratory tract and S. pneumoniae that is causing pneumonia, accurate diagnosis of pneumococcal pneumonia is a challenging issue that still needs to be solved. Sputum Gram stains and culture are the first diagnostic step for identifying pneumococcal pneumonia and provide information on antibiotic susceptibility. However, these conventional methods are relatively slow and insensitive and show limited specificity. In the past decade, new diagnostic tools have been developed, particularly antigen (teichoic acid and capsular polysaccharides) and nucleic acid (ply, lytA, and Spn9802) detection assays. Use of the pneumococcal antigen detection methods along with biomarkers (C-reactive protein and procalcitonin) may enhance the specificity of diagnosis for pneumococcal pneumonia. This article provides an overview of current methods of diagnosing pneumococcal pneumonia and discusses new and future test methods that may provide the way forward for improving its diagnosis.

Pneumococcal urinary antigen positivity in healthy colonized children: is it age dependent?

BACKGROUND

Pneumococcal urinary antigen test is a valuable tool for diagnosing pneumococcal pneumonia and meningitis in adults. Its use in children is generally not accepted because of nonspecificity at this age. It is frequently positive in asymptomatic nasopharyngeal carriers. The aim of our study was to assess the age limit from which the test is no longer positive in asymptomatic healthy carriers.

METHODS

A total of 197 children aged 36-83 months attending 9 day care centers in Prague were enrolled during February and March 2010. Nasopharyngeal swab specimens were collected from each participant and selectively cultivated. The presence of pneumococcal antigen in urine was detected by BinaxNOW® S. pneumoniae kit.

RESULTS

Streptococcus pneumoniae was cultivated in 53.3 % of healthy children with the highest colonization rate (59.3 %) in children aged 48-59 months. The most frequently colonizing serotypes were: 19F, 23F, 3, 19A, 6B and 4. The presence of pneumococcal antigen in urine decreased with age from 39.0 % in 36-47 months to 17.9 % in 72-83 months old (p = 0.031). The antigen positivity was serotype-dependent and more frequent in nonvaccinated children.

CONCLUSION

We demonstrated age-dependent linear decrease of pneumococcal antigen excretion into urine in healthy children. The positivity rate of the test in children aged 72-83 months was similar to that referred in healthy adults, irrespective of colonization. To confirm this age limit for use of this test in diagnostics of pneumococcal diseases, further study in school-age children is justified.

Pneumococcal pneumonia - Are the new severity scores more accurate in predicting adverse outcomes?

INTRODUCTION

The site-of-care decision is one of the most important factors in the management of patients with community-acquired pneumonia. The severity scores are validated prognostic tools for community-acquired pneumonia mortality and treatment site decision. The aim of this paper was to compare the discriminatory power of four scores - the classic PSI and CURB65 ant the most recent SCAP and SMART-COP - in predicting major adverse events: death, ICU admission, need for invasive mechanical ventilation or vasopressor support in patients admitted with pneumococcal pneumonia.

METHODS

A five year retrospective study of patients admitted for pneumococcal pneumonia. Patients were stratified based on admission data and assigned to low-, intermediate-, and high-risk classes for each score. Results were obtained comparing low versus non-low risk classes.

RESULTS

We studied 142 episodes of hospitalization with 2 deaths and 10 patients needing mechanical ventilation and vasopressor support. The majority of patients were classified as low risk by all scores - we found high negative predictive values for all adverse events studied, the most negative value corresponding to the SCAP score. The more recent scores showed better accuracy for predicting ICU admission and need for ventilation or vasopressor support (mostly for the SCAP score with higher AUC values for all adverse events).

CONCLUSIONS

The rate of all adverse outcomes increased directly with increasing risk class in all scores. The new gravity scores appear to have a higher discriminatory power in all adverse events in our study, particularly, the SCAP score.

Viral and bacterial aetiology of community-acquired pneumonia in adults

BACKGROUND

Modern molecular techniques reveal new information on the role of respiratory viruses in community-acquired pneumonia. In this study, we tried to determine the prevalence of respiratory viruses and bacteria in patients with community-acquired pneumonia who were admitted to the hospital.

METHODS

Between April 2008 and April 2009, 408 adult patients (aged between 20 and 94 years) with community-acquired pneumonia were tested for the presence of respiratory pathogens using bacterial cultures, real-time PCR for viruses and bacteria, urinary antigen testing for Legionella and Pneumococci and serology for the presence of viral and bacterial pathogens.

RESULTS

Pathogens were identified in 263 (64·5%) of the 408 patients. The most common single organisms in these 263 patients were Streptococcus pneumoniae (22·8%), Coxiella burnetii (6·8%) and influenza A virus (3·8%). Of the 263 patients detected with pathogens, 117 (44·5%) patients were positive for one or more viral pathogens. Of these 117 patients, 52 (44·4%) had no bacterial pathogen. Multiple virus infections (≥2) were found in 16 patients.

CONCLUSION

In conclusion, respiratory viruses are frequently found in patients with CAP and may therefore play an important role in the aetiology of this disease.

Systematic review and meta-analysis of a urine-based pneumococcal antigen test for diagnosis of community-acquired pneumonia caused by Streptococcus pneumoniae

Standard culture methods for diagnosis of Streptococcus pneumoniae pneumonia take at least 24 h. The BinaxNOW urine-based test for S. pneumoniae (BinaxNOW-SP) takes only 15 min to conduct, potentially enabling earlier diagnosis and targeted treatment. This study was conducted to assess whether the use of BinaxNOW-SP at the time of hospital admission would provide adequate sensitivity and specificity for diagnosis of community-acquired pneumonia (CAP) in adult patients. We searched PubMed, EMBASE/OVID, Cochrane Collaboration, Centre for Reviews and Dissemination, INAHTA, and CADTH for diagnostic or etiologic studies of hospitalized predominately adult patients with clinically defined CAP that reported the diagnostic performance of BinaxNOW-SP versus cultures. Two authors independently extracted study details and diagnostic two-by-two tables. We found that 27 studies met our inclusion criteria, and three different reference standards were used between them. A bivariate meta-analysis of 12 studies using a composite of culture tests as the reference standard estimated the sensitivity of BinaxNOW-SP as 68.5% (95% credibility interval [CrI], 62.6% to 74.2%) and specificity as 84.2% (95% CrI, 77.5% to 89.3%). A meta-analysis of all 27 studies, adjusting for the imperfect and variable nature of the reference standard, gave a higher sensitivity of 74.0% (CrI, 66.6% to 82·3%) and specificity of 97.2% (CrI, 92.7% to 99.8%). The analysis showed substantial heterogeneity across studies, which did not decrease with adjustment for covariates. We concluded that the higher pooled sensitivity (compared to culture) and high specificity of BinaxNOW-SP suggest it would be a useful addition to the diagnostic workup for community-acquired pneumonia. More research is needed regarding the impact of BinaxNOW-SP on clinical practice.

Estimating the burden of pneumococcal pneumonia among adults: a systematic review and meta-analysis of diagnostic techniques

Background

Pneumococcal pneumonia causes significant morbidity and mortality among adults. Given limitations of diagnostic tests for non-bacteremic pneumococcal pneumonia, most studies report the incidence of bacteremic or invasive pneumococcal disease (IPD), and thus, grossly underestimate the pneumococcal pneumonia burden. We aimed to develop a conceptual and quantitative strategy to estimate the non-bacteremic disease burden among adults with community-acquired pneumonia (CAP) using systematic study methods and the availability of a urine antigen assay.

Methods and Findings

We performed a systematic literature review of studies providing information on the relative yield of various diagnostic assays (BinaxNOW® S. pneumoniae urine antigen test (UAT) with blood and/or sputum culture) in diagnosing pneumococcal pneumonia. We estimated the proportion of pneumococcal pneumonia that is bacteremic, the proportion of CAP attributable to pneumococcus, and the additional contribution of the Binax UAT beyond conventional diagnostic techniques, using random effects meta-analytic methods and bootstrapping. We included 35 studies in the analysis, predominantly from developed countries. The estimated proportion of pneumococcal pneumonia that is bacteremic was 24.8% (95% CI: 21.3%, 28.9%). The estimated proportion of CAP attributable to pneumococcus was 27.3% (95% CI: 23.9%, 31.1%). The Binax UAT diagnosed an additional 11.4% (95% CI: 9.6, 13.6%) of CAP beyond conventional techniques. We were limited by the fact that not all patients underwent all diagnostic tests and by the sensitivity and specificity of the diagnostic tests themselves. We address these resulting biases and provide a range of plausible values in order to estimate the burden of pneumococcal pneumonia among adults.

Conclusions

Estimating the adult burden of pneumococcal disease from bacteremic pneumococcal pneumonia data alone significantly underestimates the true burden of disease in adults. For every case of bacteremic pneumococcal pneumonia, we estimate that there are at least 3 additional cases of non-bacteremic pneumococcal pneumonia.

Clinical application of sepsis biomarkers

Sepsis is one of the leading causes of death in the critically ill. Early diagnosis is important to avoid delay in instituting appropriate treatment. However, diagnosis can be delayed because of difficulty in interpreting clinical features. Sepsis biomarkers can aid early diagnosis. This article reviews the application of readily available biomarkers for diagnosis of sepsis, for predicting prognosis, and for antibiotic stewardship. 178 biomarkers are described in the literature--ranging from specimen cultures, which lack sensitivity and specificity for early diagnosis of sepsis, to biomarkers such as C-reactive protein, procalcitonin, and genetic biomarkers, which have their own limitations. Future research will mainly focus on use of more than one biomarker, but the main problem in sepsis biomarker research seems to be a lack of a recommended biomarker.

[Multidisciplinary guidelines for the management of community-acquired pneumonia]

Community-acquired pneumonia (CAP) is an infectious respiratory disease with an incidence that ranges from 3 to 8 cases per 1,000 inhabitants per year. This incidence increases with age and comorbidities. Forty per cent of CAP patients require hospitalization and around 10% of these patients are admitted in an Intensive Care Unit (ICU). Several studies have suggested that the implementation of clinical guidelines has a positive impact in the outcome of patients including mortality and length of stay. The more recent and used guidelines are those from Infectious Diseases Society of America/American Thoracic Society, published in 2007, the 2009 from the British Thoracic Society, and that from the European Respiratory Society/European Society of Clinical Microbiology and Infectious Diseases, published in 2010. In Spain, the most recently released guideline is the Sociedad Española de Neumología y Cirugía Torácica-2011 guideline. The present guidelines GNAC are designed to be used by the majority of health-care professionals that can participate in the care of CAP patients including diagnosis, decision of hospital and ICU admission, treatment and prevention. The Centro Cochrane Iberoamericano (CCIB) has participated in summarizing the previous guidelines and in the bibliography search. For each one of the following sections the panel of experts has developed a table with recommendations classified according to its evidence, strength and practical applicability using the Grading of Recommendations of Assessment Development and Evaluations (GRADE) system: 1. Epidemiology, microbiological etiology and antibiotic resistances.2. Clinical and microbiological diagnosis.3. Prognostic scales and decision of hospital admission.4. ICU admission criteria. 5. Empirical and definitive antibiotic treatment.6. Treatment failure. 7. Prevention.

Evaluation of a rapid test for the diagnosis of pneumococcal pneumonia

We evaluated the usefulness of a rapid immunochromatographic pneumococcal urinary antigen test (UAT) for the diagnosis of pneumonia over a period of five years. The UAT was positive in 32 (2.3%) urine samples obtained from 1414 patients. In 46 of these 1414 patients results of UAT and/or sputum/pleural fluid culture and/or blood culture and/or procalcitonin levels were available and therefore the study was concentrated on these patients. A concordance between UAT positivity and the presence of Streptococcus pneumoniae in the sputum was observed in only 4 of 46 (8.7%) patients for which both urine and sputum samples were analyzed. A discordant result (UAT positive and absence of S. pneumoniae in sputum samples) was recorded in 8 of 46 (17.4 %) patients. UAT negative results with sputum culture positive for S. pneumoniae were recorded in 28.3% of patients. In 20 patients, UAT tested positive but sputum culture was not performed. A concordance between UAT positivity and the isolation of S. pneumoniae from blood was seen in 2 of 46 patients whereas a discordant result (UAT positive and blood culture negative) was seen in 12 (26.1%) patients. A concordance between the UAT and high levels (≥2ng/ml) of procalcitonin was observed in 4 out of 46 patients, whereas a positive UAT result and a procalcitonin negative result were observed in 2 patients. In our experience the UAT allows the detection of the etiological agent of pneumonia, and also when sputum and/or blood cultures are negative for S. pneumoniae, when the clinical picture is suggestive of alveolar pneumonia.

Diagnostic usefulness of ribosomal protein l7/l12 for pneumococcal pneumonia in a mouse model

The capsular antigen detection (CAD) kit is widely used in clinics to detect Streptococcus pneumoniae infection from urine, because it is rapid, convenient, and effective. However, there are several disadvantages, including false-positive results in children colonized with S. pneumoniae and prolonged positive readings even after the bacteria have been cleared. RP-L7/L12 is a component of the 50S ribosome that is abundant in all bacteria and is specific for each bacterial species. We investigated whether RP-L7/L12 could be used to accurately diagnose pneumococcal pneumonia infection in mouse models of pneumonia and colonization generated by infecting CBA/JN or CBA/N mice, respectively, with S. pneumoniae strain 741. RP-L7/L12 detection by enzyme-linked immunosorbent assay accurately assessed active lung infection, as RP-L7/L12 levels decreased simultaneously with the bacterial lung burden after imipenem administration in the pneumonia mouse model. Based on the data, antibodies detecting RP-L7/L12 were applied to rapid immunochromatographic strips (ICS) for urine sample testing. When we compared the ICS test with the CAD kit in the pneumonia model, the results correlated well. Interestingly, however, when the lung bacterial burden became undetectable after antibiotic treatment, the ICS test was correspondingly negative, even though the same samples tested by the CAD kit remained positive. Similarly, while the ICS test exhibited negative results in the nasal colonization model, the CAD kit demonstrated positive results. Bacterial RP-L7/L12 may be a promising target for the development of new methods to diagnose infectious disease. Further studies are warranted to determine whether such a test could be useful in children.

Swedish guidelines on the management of community-acquired pneumonia in immunocompetent adults--Swedish Society of Infectious Diseases 2012

This document presents the 2012 evidence based guidelines of the Swedish Society of Infectious Diseases for the in- hospital management of adult immunocompetent patients with community-acquired pneumonia (CAP). The prognostic score 'CRB-65' is recommended for the initial assessment of all CAP patients, and should be regarded as an aid for decision-making concerning the level of care required, microbiological investigation, and antibiotic treatment. Due to the favourable antibiotic resistance situation in Sweden, an initial narrow-spectrum antibiotic treatment primarily directed at Streptococcus pneumoniae is recommended in most situations. The recommended treatment for patients with severe CAP (CRB-65 score 2) is penicillin G in most situations. In critically ill patients (CRB-65 score 3-4), combination therapy with cefotaxime/macrolide or penicillin G/fluoroquinolone is recommended. A thorough microbiological investigation should be undertaken in all patients, including blood cultures, respiratory tract sampling, and urine antigens, with the addition of extensive sampling for more uncommon respiratory pathogens in the case of severe disease. Recommended measures for the prevention of CAP include vaccination for influenza and pneumococci, as well as smoking cessation.

Urine as a specimen to diagnose infections in twenty-first century: focus on analytical accuracy

Urine as a clinical specimen to diagnose infections has been used since ancient times. Many rapid technologies to assist diagnosis of infections are currently in use. Alongside traditional enzyme immunoassays (EIA), new technologies have emerged. Molecular analysis of transrenal DNA to diagnose infections is also a rapidly growing field. The majority of EIAs utilize the detection of excreted sugar compounds of the outer microbial cell-wall shed into the bloodstream and excreted into the urine. This mini-review focuses on current knowledge on rapid urinary antigen detection tests to diagnose most common infections, and highlights their diagnostic utility. The past and the future of urinalysis are also briefly discussed. The analysis of the literature shows that some methods are not quantitative, and analytical sensitivity may remain suboptimal. In addition, the performance criteria and technical documentation of some commercial tests are insufficient. Clinical microbiologists and physicians should be alert to assay limitations.

Evaluation of a rapid immunochromatographic ODK-0901 test for detection of pneumococcal antigen in middle ear fluids and nasopharyngeal secretions

Since the incidence of penicillin-resistant Streptococcus pneumoniae has been increasing at an astonishing rate throughout the world, the need for accurate and rapid identification of pneumococci has become increasingly important to determine the appropriate antimicrobial treatment. We have evaluated an immunochromatographic test (ODK-0901) that detects pneumococcal antigens using 264 middle ear fluids (MEFs) and 268 nasopharyngeal secretions (NPSs). A sample was defined to contain S. pneumoniae when optochin and bile sensitive alpha hemolytic streptococcal colonies were isolated by culture. The sensitivity and specificity of the ODK-0901 test were 81.4% and 80.5%, respectively, for MEFs from patients with acute otitis media (AOM). In addition, the sensitivity and specificity were 75.2% and 88.8%, respectively, for NPSs from patients with acute rhinosinusitis. The ODK-0901 test may provide a rapid and highly sensitive evaluation of the presence of S. pneumoniae and thus may be a promising method of identifying pneumococci in MEFs and NPSs.

Guidelines for the management of adult lower respiratory tract infections--summary

This document is an update of Guidelines published in 2005 and now includes scientific publications through to May 2010. It provides evidence-based recommendations for the most common management questions occurring in routine clinical practice in the management of adult patients with LRTI. Topics include management outside hospital, management inside hospital (including community-acquired pneumonia (CAP), acute exacerbations of COPD (AECOPD), acute exacerbations of bronchiectasis) and prevention. The target audience for the Guideline is thus all those whose routine practice includes the management of adult LRTI.

A retrospective analysis of 111 cases of pneumococcal pneumonia: clinical features and prognostic factors

OBJECTIVE

Streptococcus pneumoniae is an important and common pathogen of acute pneumonia. The urinary pneumococcal antigen test has been increasingly used for the diagnosis of pneumococcal pneumonia, but there have been few studies on pneumococcal pneumonia after this test became prevalent. The present study was conducted to characterize the clinical features of pneumococcal pneumonia after the introduction of the urinary antigen test.

METHODS

We retrospectively analyzed 111 cases from 105 patients with pneumococcal pneumonia in our hospital between 2007 and 2010, and collected data regarding background characteristics, laboratory data, isolated bacteria, and clinical courses.

RESULTS

The cases analysed included 77 of community-acquired pneumonia (CAP), 21 of healthcare-associated pneumonia (HCAP), and 13 of hospital-acquired pneumonia (HAP). Penicillin-resistant Streptococcus pneumoniae was isolated in 12.5 and 55.6% of non-HAP and HAP cases, respectively. When the cases were divided into 5 groups according to A-DROP scores (0, 1, 2, 3 and 4 points), critical events occurred at 0, 0, 8.7, 15.4, and 75.0% in groups of cases of 0, 1, 2, 3, and 4 points, respectively. Similarly, critical events occurred at 66.7, 4.7, 3.8, and 9.1% in groups of cases according to WBC counts of <4,000, 4,000-9,999, 10,000-19,999, and ≥20,000 cells/µL, respectively.

CONCLUSION

Most of the pneumococcal pneumonia cases occurred as CAP and were treated successfully. HAP cases were frequently penicillin resistant. Elevated A-DROP scores and decreased WBC counts were found to be predictive of critical events.

Guidelines for the management of adult lower respiratory tract infections--full version

This document is an update of Guidelines published in 2005 and now includes scientific publications through to May 2010. It provides evidence-based recommendations for the most common management questions occurring in routine clinical practice in the management of adult patients with LRTI. Topics include management outside hospital, management inside hospital (including community-acquired pneumonia (CAP), acute exacerbations of COPD (AECOPD), acute exacerbations of bronchiectasis) and prevention. Background sections and graded evidence tables are also included. The target audience for the Guideline is thus all those whose routine practice includes the management of adult LRTI.