Diagnosis Of Pneumococcal Pneumonia Research Articles

Misdiagnosis Due to False-Positive Detection of Pneumococcal Urinary Antigen.

IntroductionThe detection of pneumococcal antigens in urine is an alternative to gram staining, and their culture is central to the diagnosis of pneumococcal pneumonia. We present a case of the false-positive detection of urinary Streptococcus species pneumococcal antigen with a BinaxNOW test. This resulted in delayed diagnosis of a liver abscess.Case descriptionA 70-year-old woman presented to the emergency department with a 1-day history of chills and difficulty walking. She had a fever and her physical examination was normal. Non-contrast chest computed tomography (CT) revealed a slight ground-glass opacity in the left lower lobe. Laboratory tests revealed liver injury and elevated C-reactive protein levels. A urinary pneumococcal antigen test was positive, and she was diagnosed with acute bronchopneumonia caused by Streptococcus pneumoniae. She was treated with ceftriaxone. However, abdominal contrast-enhanced CT performed the next day revealed portal vein thrombus and a left lobe liver abscess. Streptococcus constellatus was detected in a puncture specimen of the liver abscess. It was concluded that the positive urinary pneumococcal antigen test was a false-positive owing to Streptococcus infection.DiscussionFalse-positive results might be explained by the presence of C-polysaccharide antigens in the cell wall of S. pneumoniae. The positive urinary antigen test together with the finding of slight ground-glass opacity in the left lung on chest CT initially led to misdiagnosis. False positives may result in misdiagnosis and unnecessary antimicrobial therapy.ConclusionThe overuse of the pneumococcal urinary antigen tests can lead to false positives and misdiagnosis.LEARNING POINTSFalse-positive pneumococcal urinary antigen results may lead to the misdiagnosis of pneumococcal pneumonia caused by Streptococcus pneumoniae and unnecessary antimicrobial therapy.False-positive results can occur in patients with infections caused by other Streptococcus species (e.g., liver abscess caused by Streptococcus constellatus).The optimal use of pneumococcal urinary antigen tests needs to be studied in clinical practice settings.

Pneumococcal pneumonia among shipyard workers: Inside the features of disease onset

BackgroundSeveral outbreaks of pneumococcal pneumonia among shipyard workers have been described. In this study, following a previous report of grouped cases, we aimed to elucidate the features of disease onset. MethodsWe compared the population characteristics of shipyard workers with a confirmed diagnosis of pneumococcal pneumonia (N = 38) to those of workers without pneumonia (N = 53). We compared nine S. pneumoniae strains isolated from patients with pneumonia by capsular serotyping, multi-locus sequence typing, and whole genome sequencing. ResultsShipyard workers with Streptococcus pneumoniae pneumonia were more frequently from Italy (P = 0.016), had at least one underlying condition (P = 0.024), lived on-board the ship (P = 0.009). None of these factors was independent by multivariate analysis. While capsular serotyping enabled us to identify four different serotypes: 4 (n = 5), 8 (n = 2), 9 N (n = 1), and 3 (n = 1), by sequence typing, we distinguished five sequence types (STs): ST801 (n = 4), ST205 (n = 2), ST1220 (n = 1), ST1280 (n = 1), and ST66 (n = 1). Whole genome sequencing confirmed the results obtained by MLST. Genomes of isolates of the same sequence type were similar with ≤80 single-nucleotide polymorphisms. ConclusionsWe confirmed that the onset of pneumococcal infection among shipyard workers was attributable to both a person-to-person spread of single strains of S. pneumoniae and a shift of different strains from commensal to pathogen under favourable conditions (professional exposure, viral infections). Control measures should therefore be implemented by taking into account these features.

Improvement of pneumococcal pneumonia diagnosis using quantitative real-time PCR targeting lytA in adult patients: a prospective cohort study

ObjectivesThe aim of the study was to assess the performance of real-time PCR targeting the lytA gene (rtPCR-lytA) in plasma, urine and nasopharyngeal (NP) samples for the diagnosis of pneumococcal community-acquired pneumonia (P-CAP). MethodsProspective observational study including all consecutive adults with CAP from November 2015 to May 2017. P-CAP was defined if pneumococcus was identified using conventional methods (CM) and/or a positive rtPCR-lytA was detected in blood, urine or NP samples (NP cut-off ≥8000 copies/mL). Diagnostic performance of each test was calculated. ResultsA total of 133 individuals with CAP were included. Of these, P-CAP was diagnosed in 62 (46.6%). The proportion of P-CAP diagnosed by rtPCR-lytA methods was significantly higher than that diagnosed by CM (87.1% versus 59.7%, p 0.005). The rtPCR-lytA identified Streptococcus pneumoniae in 25 patients (40.3% of all individuals with P-CAP) whose diagnosis would have been missed by CM. NP-rtPCR-lytA allowed diagnosis of 62.3% of P-CAP. A nasopharyngeal colonization density ≥2351 copies/mL predicted P-CAP diagnosis (area under the curve = 0.82, sensitivity 83.3%, specificity 80.9%). There was a positive correlation between increasing bacterial load in blood and CURB-65 score (Spearman correlation coefficient r = 0.4, p 0.001), pneumonia severity index (r = 0.3, p 0.02) and time to clinical stability (r = 0.33, p 0.01). Median bacterial load in blood was higher in P-CAP patients with bacteraemia (0.65 × 103 versus 0 × 103 copies/mL, p 0.002), intensive care unit admission (0.68 × 103 versus 0 × 103 copies/mL, p 0.04) or mechanical ventilation (7.45 × 103 versus 0 × 103 copies/mL, p 0.04). ConclusionsThe use of rtPCR-lytA methods significantly increased the diagnosis of P-CAP compared with CM. Nasopharyngeal swabs rtPCR-lytA detection, with an accurate cut-off value, was the most promising among molecular methods for the diagnosis of P-CAP.

Diagnostic and Management Errors in an Immunodeficient Patient with Pneumococcal Pneumonia with Bacteraemia due to Incorrect Assessment of the Patient's Immune Status.

Knowing the immune status of patients with infectious disease is vital for accurate clinical decision-making.Patients are sometimes unaware of their immunodeficiency despite having signs indicating indolent immunodeficiency, such as a history of recurrent osteomyelitis.Inferring and clarifying the immunodeficiency behind the patient's history was the turning point in this diagnosis.

Diagnostic and Management Errors in an Immunodeficient Patient with Pneumococcal Pneumonia with Bacteraemia due to Incorrect Assessment of the Patient’s Immune Status

A 79-year-old woman presented with fever and pleural chest pain. Based on the assessment of mild community pneumonia in an immunocompetent patient, outpatient follow-up was planned. However, the patient was admitted several hours later with a diagnosis of pneumococcal pneumonia with bacteraemia. In addition, selective immunoglobulin M deficiency was detected. In this case, although a history of recurrent osteomyelitis was provided, the physicians overlooked the information suggesting immunodeficiency, which led to an incorrect diagnostic and management decision. Obtaining the past medical history is essential, but utilizing it is even more important to avoid clinical decision-making errors.

Detection of Streptococcus pneumoniae antigen in pleural fluid: usefulness of an immunofluorescence-based lateral flow assay for the diagnosis of pneumococcal pneumonia

The performance of an immunofluorescence-based Streptococcus pneumoniae antigen detection test in pleural fluid (IF-PF) was evaluated. For proven and possible pneumococcal pneumonias global sensitivity and specificity were 92.6 (95 CI 76.6–97.9) and 80 (95 CI 62.7–90.5), respectively, with no significant differences between children and adults. Global diagnostic accuracy of IF-PF was 86% (74.2–93.7), and a substantial k index of concordance with culture/RT-PCR of 0.716 (0.535–0.896). IF-PF might be useful as a rapid complementary test for the etiologic diagnosis of pneumococcal pneumonia.

Performance of pneumococcal urinary antigen test in patients with community-onset pneumonia: a propensity score-matching study.

Background/AimsAlthough pneumococcal urinary antigen tests (PUATs) have universally been used for the diagnosis of pneumococcal pneumonia, data on the efficacy of these exams are limited. The objective of our study was to investigate the clinical impact of the PUAT in patients with community-onset pneumonia (CO-pneumonia).MethodsWe conducted a retrospective cohort study of patients diagnosed with CO-pneumonia. Patients were classified according to their PUAT results and were matched using the propensity score-matching method. The primary outcome was 30-day mortality.ResultsA total of 1,257 patients were identified and 163 (13.0%) demonstrated positive PUAT results. The sensitivity and specificity values of PUAT for overall pneumococcal pneumonia were 56.5% and 91.4%, respectively. In the full cohort, there were no significant differences in 30-day mortality between the two groups (6.1% in the positive PUAT group vs. 8.2% in the negative PUAT group, p = 0.357). However, in the propensity-matched cohort, the 30-day mortality rates were lower in the positive PUAT group (5.6% vs. 17.4%, p = 0.001). With respect to secondary outcomes, the proportion of patients with potentially drug-resistant pathogens, changes in antibiotics, and failure rates of initial antibiotic therapy were significantly lower in the positive PUAT group than in the negative PUAT group of the propensity-matched cohort.ConclusionsWe found that the sensitivity of the index test was low and specificity was high in this clinical setting. And our findings suggest that positive PUAT results may be associated with favorable clinical outcomes in patients with CO-pneumonia.

Assessment of an Antibody-in-Lymphocyte Supernatant Assay for the Etiological Diagnosis of Pneumococcal Pneumonia in Children.

New diagnostic tests for the etiology of childhood pneumonia are needed. We evaluated the antibody-in-lymphocyte supernatant (ALS) assay to detect immunoglobulin (Ig) G secretion from ex vivo peripheral blood mononuclear cell (PBMC) culture, as a potential diagnostic test for pneumococcal pneumonia. We enrolled 348 children with pneumonia admitted to Patan Hospital, Kathmandu, Nepal between December 2015 and September 2016. PBMCs sampled from participants were incubated for 48 h before harvesting of cell culture supernatant (ALS). We used a fluorescence-based multiplexed immunoassay to measure the concentration of IgG in ALS against five conserved pneumococcal protein antigens. Of children with pneumonia, 68 had a confirmed etiological diagnosis: 12 children had pneumococcal pneumonia (defined as blood or pleural fluid culture-confirmed; or plasma CRP concentration ≥60 mg/l and nasopharyngeal carriage of serotype 1 pneumococci), and 56 children had non-pneumococcal pneumonia. Children with non-pneumococcal pneumonia had either a bacterial pathogen isolated from blood (six children); or C-reactive protein <60 mg/l, absence of radiographic consolidation and detection of a pathogenic virus by multiplex PCR (respiratory syncytial virus, influenza viruses, or parainfluenza viruses; 23 children). Concentrations of ALS IgG to all five pneumococcal proteins were significantly higher in children with pneumococcal pneumonia than in children with non-pneumococcal pneumonia. The concentration of IgG in ALS to the best-performing antigen discriminated between children with pneumococcal and non-pneumococcal pneumonia with a sensitivity of 1.0 (95% CI 0.73–1.0), specificity of 0.66 (95% CI 0.52–0.78) and area under the receiver-operating characteristic curve (AUROCC) 0.85 (95% CI 0.75–0.94). Children with pneumococcal pneumonia were older than children with non-pneumococcal pneumonia (median 5.6 and 2.0 years, respectively, p < 0.001). When the analysis was limited to children ≥2 years of age, assay of IgG ALS to pneumococcal proteins was unable to discriminate between children with pneumococcal pneumonia and non-pneumococcal pneumonia (AUROCC 0.67, 95% CI 0.47–0.88). This method detected spontaneous secretion of IgG to pneumococcal protein antigens from cultured PBMCs. However, when stratified by age group, assay of IgG in ALS to pneumococcal proteins showed limited utility as a test to discriminate between pneumococcal and non-pneumococcal pneumonia in children.

Influence of Older Age and Other Risk Factors on Pneumonia Hospitalization in Switzerland in the Pneumococcal Vaccine Era.

Background: Pneumococcal pneumonia is a disease of the extremes of age. However, as other traditional risk factors for pneumococcal pneumonia also increase with older age, it is unclear if older age itself should be an indication for pneumococcal vaccination. Therefore, we assessed the effect of age on risk for hospitalization for pneumonia and for pneumococcal pneumonia.Methods: Using a national hospitalization dataset, all patients ≥16 years hospitalized in a Swiss hospital with a diagnosis of pneumonia or pneumococcal pneumonia between 2002 and 2015 were included. Multivariable logistic regression analysis was used to test the association between age (≥50 or ≥65 years) and hospitalization for pneumonia or pneumococcal pneumonia after adjusting for pneumococcal vaccine indications. Similar analyses were performed for effect of age on length of stay (LOS) and mortality.Results: Among a total of 17,619,016 hospitalizations a diagnosis of pneumonia was present in 421,760 (2.4%) and a diagnosis of pneumococcal pneumonia in 21,610 (0.12%). Age ≥50 years (OR: 3.52 and 2.12, respectively; p for both <0.001) and age ≥65 years (OR: 2.98 and 1.80, respectively; p for both <0.001) as well as most Swiss pneumococcal vaccine indications were independent predictors of hospitalization with a pneumonia and pneumococcal pneumonia diagnosis, respectively. Older age with both age cut-offs were associated with increased LOS (≥50 years: aRR: 1.19 and 1.24, respectively; age ≥65 years: aRR: 1.60 and 1.20, respectively; p < 0.001 for all) and mortality (≥50 years: aOR: 4.73 and 2.84, respectively; age ≥65 years: aOR: 2.38 and 2.69, respectively, p < 0.001 for all) in patients with a pneumonia and pneumococcal pneumonia diagnosis, respectively. The effects of pneumococcal vaccine indications decreased with older age. The incidences of hospitalizations with a pneumonia diagnosis and a pneumococcal pneumonia diagnosis increased significantly from the pre-vaccine era to the PCV7 era and the PCV13 era (p for trend for both analyses <0.001).Conclusion: This study confirms the Swiss indications for pneumococcal vaccination as independent risk factors for pneumonia hospitalizations. Older age itself should be considered as an additional vaccine indication. Pneumonia and pneumococcal pneumonia in adults have increased despite pneumococcal vaccination in children.

Treatment and Prevention of Pneumococcal Infection.

Streptococcus pneumoniae, a gram-positive diplococcus, is the most common cause of bacterial pneumonia. The diagnosis of pneumococcal pneumonia is usually confirmed by chest x-ray and gram stain. The most appropriate antibiotics for treatment pneumococcal infection are macrolides, beta-lactams, and quinolones. Two vaccines, PPSV23 and PCV13, are highly effective in preventing infection.

Pneumococcal pneumonia and invasive pneumococcal disease: immunopathogenesis and diagnosis

Abstract Streptococcus pneumoniae is the most common aetiology of community-acquired pneumonia (CAP). It has many virulence factors, the most important being a polysaccharide capsule (Cps). There are 97 different serotypes of pneumococcal based on Cps which include both colonization and invasive serotypes. Pneumococcal pneumonia may exist as a result of either aspiration of bacteria in the nasopharynx or inhalation of droplet nuclei which contains bacteria until they reach the lower respiratory tract. This condition will activate both innate and adaptive immune system. The diagnosis of pneumococcal pneumonia is established in a patient who has the signs and symptoms of pneumonia, accompanied by the detection of S. pneumoniae in microbiology examination. Pneumococcus may also penetrate into a normally sterile site such as bloodstream, meninges, and pleural cavity, and infection of pneumococcus in those sites are defined as an invasive pneumococcal disease (IPD). High bacterial load, dysfunction of the immune system, and co-colonization of another microorganism may also lead to IPD.

Detection rate of Pneumococcal Pneumonia using the Urine Antigen Kit BinaxNow Streptococcus Pneumoniae Test: a Prospective Cohort Study in a Tertiary Hospital in Malaysia

Background: Pneumococcal pneumonia is the commonest type of bacterial pneumonia worldwide. In Malaysia, the reported incidence of pneumococcal pneumonia is low. This may be due to poor sensitivity of conventional methods. The use of BinaxNOW, a urinary antigen test for Streptococcus pneumoniae can aid in the diagnosis of pneumococcal pneumonia. Objective: To determine the detection rate of pneumococcal pneumonia using BinaxNOW kit and to compare this with the conventional culture method for blood and sputum. Methods: This was a prospective cohort study involving patients 18 year-old and above admitted for community-acquired pneumonia (CAP) or health-care associated pneumonia (HCAP) to UKMMC between December 2011 and June 2012. BinaxNOW test, serology for Mycoplasma, Legionella and Chlamydia and cultures from blood/sputum/other respiratory tract samples and other routine investigations were performed. Results: A total of 102 patients were recruited; 89 (87.3%) with CAP, 13 (12.7%) with HCAP. 57 (55.9%) had pneumonia of unknown aetiology, 11 patients (10.8%) had positive blood cultures, 8 patients (7.8%) had a positive urine BinaxNOW test and 6 patients (5.9%) had positive sputum cultures. Streptococcus pneumoniae was the commonest isolate accounting for 9 cases (8.8%) followed by Klebsiella pneumoniae in 7 cases (6.9%). 8 out of 9 patients with positive urine BinaxNOW test had negative cultures for Streptococcus pneumoniae. One patient grew Streptococcus pneumoniae from the tracheal aspirate however the urine BinaxNOW test was negative. Conclusion: The use of urine BinaxNOW kit in UKMMC increased the detection rate of pneumococcal pneumonia in hospitalized patients.

Detection of Pneumococcal DNA in Blood by Polymerase Chain Reaction for Diagnosing Pneumococcal Pneumonia in Young Children From Low- and Middle-Income Countries.

Background.We investigated the performance of polymerase chain reaction (PCR) on blood in the diagnosis of pneumococcal pneumonia among children from 7 low- and middle-income countries.Methods.We tested blood by PCR for the pneumococcal autolysin gene in children aged 1–59 months in the Pneumonia Etiology Research for Child Health (PERCH) study. Children had World Health Organization–defined severe or very severe pneumonia or were age-frequency–matched community controls. Additionally, we tested blood from general pediatric admissions in Kilifi, Kenya, a PERCH site. The proportion PCR-positive was compared among cases with microbiologically confirmed pneumococcal pneumonia (MCPP), cases without a confirmed bacterial infection (nonconfirmed), cases confirmed for nonpneumococcal bacteria, and controls.Results.In PERCH, 7.3% (n = 291/3995) of cases and 5.5% (n = 273/4987) of controls were blood pneumococcal PCR-positive (P < .001), compared with 64.3% (n = 36/56) of MCPP cases and 6.3% (n = 243/3832) of nonconfirmed cases (P < .001). Blood pneumococcal PCR positivity was higher in children from the 5 African countries (5.5%–11.5% among cases and 5.3%–10.2% among controls) than from the 2 Asian countries (1.3% and 1.0% among cases and 0.8% and 0.8% among controls). Among Kilifi general pediatric admissions, 3.9% (n = 274/6968) were PCR-positive, including 61.7% (n = 37/60) of those with positive blood cultures for pneumococcus.Discussion.The utility of pneumococcal PCR on blood for diagnosing childhood pneumococcal pneumonia in the 7 low- and middle-income countries studied is limited by poor specificity and by poor sensitivity among MCPP cases.

Density of Upper Respiratory Colonization With Streptococcus pneumoniae and Its Role in the Diagnosis of Pneumococcal Pneumonia Among Children Aged

Previous studies suggested an association between upper airway pneumococcal colonization density and pneumococcal pneumonia, but data in children are limited. Using data from the Pneumonia Etiology Research for Child Health (PERCH) study, we assessed this potential association. PERCH is a case-control study in 7 countries: Bangladesh, The Gambia, Kenya, Mali, South Africa, Thailand, and Zambia. Cases were children aged 1-59 months hospitalized with World Health Organization-defined severe or very severe pneumonia. Controls were randomly selected from the community. Microbiologically confirmed pneumococcal pneumonia (MCPP) was confirmed by detection of pneumococcus in a relevant normally sterile body fluid. Colonization density was calculated with quantitative polymerase chain reaction analysis of nasopharyngeal/oropharyngeal specimens. Median colonization density among 56 cases with MCPP (MCPP cases; 17.28 × 106 copies/mL) exceeded that of cases without MCPP (non-MCPP cases; 0.75 × 106) and controls (0.60 × 106) (each P < .001). The optimal density for discriminating MCPP cases from controls using the Youden index was >6.9 log10 copies/mL; overall, the sensitivity was 64% and the specificity 92%, with variable performance by site. The threshold was lower (≥4.4 log10 copies/mL) when MCPP cases were distinguished from controls who received antibiotics before specimen collection. Among the 4035 non-MCPP cases, 500 (12%) had pneumococcal colonization density >6.9 log10 copies/mL; above this cutoff was associated with alveolar consolidation at chest radiography, very severe pneumonia, oxygen saturation <92%, C-reactive protein ≥40 mg/L, and lack of antibiotic pretreatment (all P< .001). Pneumococcal colonization density >6.9 log10 copies/mL was strongly associated with MCPP and could be used to improve estimates of pneumococcal pneumonia prevalence in childhood pneumonia studies. Our findings do not support its use for individual diagnosis in a clinical setting.

The Evaluation of the Sputum Antigen Kit in the Diagnosis of Pneumococcal Pneumonia.

Objective A previously developed sputum antigen detection kit for Streptococcus pneumoniae enabled the early diagnosis of pneumococcal pneumonia using sputum samples. We conducted a prospective study to compare the sensitivity of the sputum and urinary antigen kits. Methods Pneumonia patients who were treated from April 2014 to September 2015 were recruited for the present study. Patients with pneumococcal pneumonia who could not participate in the prospective arm of the study were analyzed in the retrospective arm. Results Nine of the 69 participants in the prospective study had pneumococcal pneumonia. The sputum antigen kit results correlated well with the sputum culture results. The sensitivity of the sputum antigen kit was 88.9% (8/9), which was higher than that of the urinary antigen kit (5/9; 55.6%). When patients from the retrospective arm of the study were included, the sensitivity of the sputum culture was 93.5% (29/31), which was significantly higher than that of the urinary antigen kit (19/31; 60.6%). False positives were obtained using the sputum antigen kit in four cases. Three of the four false positives were suspected to have resulted from the administration of antibiotics prior to the use of the kit; the remaining case likely occurred due to a false reaction to S. milleri-induced pyothorax. Conclusion Collectively, our findings suggest that the sputum antigen kit has a higher sensitivity for detecting S. pneumoniae than the urinary antigen kit. However, the prior administration of antibiotics can render the sputum culture results negative or lead to a false-positive result.

Evaluation of the rapid immunochromatographic ODK0501 assay for Streptococcus pneumoniae antigen detection with nasopharyngeal swabs: preliminary report.

BackgroundEarly identification and control of pathogenic bacteria are important in the treatment of pneumonia. Currently, two rapid antigen detection kits for pneumococcal pneumonia are available: one uses urine samples and the other, named RAPIRUN® S. pneumoniae, uses sputum samples. RAPIRUN® has shown high sensitivity with nasopharyngeal swab samples from pediatric patients. In this study, we investigated the performance of RAPIRUN® with nasopharyngeal swabs from adult patients.MethodsAll adult patients diagnosed with pneumonia from November 2011 to April 2012 in St. Luke’s International hospital were included in this cross-sectional study. Single sputum, nasopharyngeal swab, and urine samples obtained from patients were investigated using a rapid antigen detection kit. Sputum and blood cultures were also evaluated. We compared the characteristics of pneumococcal pneumonia patients diagnosed using RAPIRUN with a nasopharyngeal swab to those patients diagnosed using other methods. Sensitivity and specificity were also calculated.ResultsSeventeen out of 60 patients with pneumonia were diagnosed with pneumococcal pneumonia. In 4 out of the 17 cases, a positive test result was obtained using RAPIRUN with a nasopharyngeal swab. The sensitivity and specificity were 23.5 and 100 %, respectively.ConclusionRAPIRUN performed with nasopharyngeal swabs from adult patients exhibited lower sensitivity for the diagnosis of pneumococcal pneumonia than the other compared methods. The causative pathogen of pneumonia should be identified using not only sputum cultures or rapid antigen detection kits but also clinical features or gram staining of sputum.

Evaluation of the rapid immunochromatographic ODK0501 assay for Streptococcus pneumoniae antigen detection with nasopharyngeal swabs: preliminary report

Background: Early identification and control of pathogenic bacteria are important in the treatment of pneumonia. Currently, two rapid antigen detection kits for pneumococcal pneumonia are available: one uses urine samples and the other, named RAPIRUN® S. pneumoniae, uses sputum samples. RAPIRUN® has shown high sensitivity with nasopharyngeal swab samples from pediatric patients. In this study, we investigated the performance of RAPIRUN® with nasopharyngeal swabs from adult patients. Methods: All adult patients diagnosed with pneumonia from November 2011 to April 2012 in St. Luke’s International hospital were included in this cross-sectional study. Single sputum, nasopharyngeal swab, and urine samples obtained from patients were investigated using a rapid antigen detection kit. Sputum and blood cultures were also evaluated. We compared the characteristics of pneumococcal pneumonia patients diagnosed using RAPIRUN with a nasopharyngeal swab to those patients diagnosed using other methods. Sensitivity and specificity were also calculated. Results: Seventeen out of 60 patients with pneumonia were diagnosed with pneumococcal pneumonia. In 4 out of the 17 cases, a positive test result was obtained using RAPIRUN with a nasopharyngeal swab. The sensitivity and specificity were 23.5 and 100 %, respectively. Conclusion: RAPIRUN performed with nasopharyngeal swabs from adult patients exhibited lower sensitivity for the diagnosis of pneumococcal pneumonia than the other compared methods. The causative pathogen of pneumonia should be identified using not only sputum cultures or rapid antigen detection kits but also clinical features or gram staining of sputum.

A Pneumococcal Protein Array as a Platform to Discover Serodiagnostic Antigens Against Infection

Pneumonia is one of the most common and severe diseases associated with Streptococcus pneumoniae infections in children and adults. Etiological diagnosis of pneumococcal pneumonia in children is generally challenging because of limitations of diagnostic tests and interference with nasopharyngeal colonizing strains. Serological assays have recently gained interest to overcome some problems found with current diagnostic tests in pediatric pneumococcal pneumonia. To provide insight into this field, we have developed a protein array to screen the antibody response to many antigens simultaneously. Proteins were selected by experimental identification from a collection of 24 highly prevalent pediatric clinical isolates in Spain, using a proteomics approach consisting of "shaving" the cell surface with proteases and further LC/MS/MS analysis. Ninety-five proteins were recombinantly produced and printed on an array. We probed it with a collection of sera from children with pneumococcal pneumonia. From the set of the most seroprevalent antigens, we obtained a clear discriminant response for a group of three proteins (PblB, PulA, and PrtA) in children under 4 years old. We validated the results by ELISA and an immunostrip assay showed the translation to easy-to-use, affordable tests. Thus, the protein array here developed presents a tool for broad use in serodiagnostics.

Clinical usefulness of pneumococcal urinary antigen test, stratified by disease severity and serotypes.

Early diagnosis of pneumococcal pneumonia facilitates appropriate antibiotic therapy. The urinary antigen test (UAT) is known to be useful for the diagnosis of pneumococcal pneumonia. This study aimed to evaluate the usefulness of UAT in the 13-valent pneumococcal conjugated vaccine (PCV13) era. Community-acquired pneumonia (CAP) cases aged ≥19 years were reviewed retrospectively. This study evaluated the utility of Streptococcus pneumoniae UAT (BinaxNOW® assay) for diagnosis of pneumococcal CAP, and the relation of the UAT positive rate to age, comorbidities, pneumonia severity, and pneumococcal serotypes. Among 752 microbiologically identified CAP cases, S. pneumoniae (36.7%) was the most common isolate, and of those cases, 56.4% were positive for UAT. UAT positivity varied by pneumococcal serotype (serotype 3, 50%; 9V/9A, 85%; 11A/11E, 54%; 14, 36.4%; 19A, 50%; and 23F, 37.5%), and was significantly increased since 2012, two years after introduction of PCV13. The positive rate of UAT was significantly related to CRP level (P = 0.007) and lobar pneumonia (P = 0.006), but not to age, co-morbidities or prior antibiotic therapy. In conclusion, urinary antigen detection varied depending on the S. pneumoniae serotype. In the PCV13 era, the serotype distribution of pneumococcal pneumonia may be changing, and the clinical usefulness of UAT needs to be monitored. The positive rate of UAT may be influenced by a localized bacterial burden and host reactions.

Pneumococcal pneumonia infection is associated with end-stage renal disease in adult hospitalized patients

Pneumococcal disease leads to renal complications ranging from persistent proteinuria to end-stage renal disease (ESRD) in pediatric patients. However, long-term renal effects after pneumococcal pneumonia infection in adult patients remains largely unknown. To evaluate this we conducted a population-based retrospective cohort study consisting of 18,733 adult patients at the time of pneumococcal pneumonia diagnosis, using claims data from Taiwan's National Health Insurance Research Database (NHIRD) with a comparison cohort of 73,409 age- and gender-matched patients without pneumococcal pneumonia. The overall incidence rate ratio of ESRD was 23% higher in those with pneumococcal pneumonia than in those without pneumococcal pneumonia (5.26 vs. 3.10 per 1000 person-years), with an adjusted hazard ratio of 1.14 (95% confidence interval 1.01-1.29). In addition, the risk of developing ESRD was associated with covariates including age, gender, chronic kidney disease, diabetes mellitus, hypertension, hyperlipidemia, chronic obstructive pulmonary disease, and heart failure. The ESRD cumulative incidence curve showed a considerably higher risk of ESRD in those with pneumococcal pneumonia than in those without pneumococcal pneumonia (significant by log-rank test). Thus, pneumococcal pneumonia may be associated with an increased risk of ESRD in adult patients. A long-term follow-up of renal function is recommended for adult hospitalized patients with pneumococcal pneumonia infection.