Rapid diagnosis of bacteremic pneumococcal infections in adults by using the Binax NOW Streptococcus pneumoniae urinary antigen test: a prospective,controlled clinical evaluation

The diagnosis of severe pneumococcal infections is inadequate, relying heavily on culture of Streptococcus pneumoniae from blood or other normally sterile fluids, and is severely limited by prior administration of antibiotics. We evaluated prospectively the Binax NOW S. pneumoniae urinary antigen test, a rapid immunochromatographic assay, for the diagnosis of bacteremic pneumococcal infections in hospitalized adult patients. Antigen was detected in 88 of 107 cases overall, resulting in a test sensitivity of 82% (95% confidence interval [95% CI], 74 to 89%). Antigen detection was greater in those with pneumonia (67 of 77 [87%]) than in those without pneumonia (21 of 30 [70%]) (P = 0.04). Urinary antigen was also detected in 3 of 106 adult patients with community-acquired septicemic infections caused by other organisms, giving a test specificity of 97% (95% CI, 92 to 99%). For 45 pneumococcal bacteremia patients with a positive test on treatment day 1, urinary antigen excretion was monitored for the first week of antibiotic treatment. Antigen was still detectable in 83% (29 of 35 tested; 95% CI, 66 to 93%) on treatment day 3. Detection of urinary antigen is a valuable, sensitive, and rapid test for the early diagnosis of bacteremic pneumococcal infections in adult patients, even after antibiotic treatment has commenced.     

Detection of Streptococcus pneumoniae antigen in bronchoalveolar lavage fluid samples by a rapid immunochromatographic membrane assay

We conducted a retrospective study to evaluate an immunochromatographic membrane test (ICT), applied to bronchoalveolar lavage (BAL) fluid samples obtained in patients with suspected pneumonia, for the detection of Streptococcus pneumoniae antigen. The NOW Streptococcus pneumoniae test was assessed on 96 BAL fluid samples. Sensitivity was tested in 20 samples obtained from patients diagnosed as having pneumococcal pneumonia (growth of S. pneumoniae in blood cultures and/or in BAL fluid samples of > or =10(4) CFU/ml). Specificity was tested in BAL fluid samples of nonpneumococcal etiology (n = 41) and in samples with no respiratory pathogen and a total bacterial count of <10(4) CFU/ml (n = 35). Using the ICT, pneumococcal antigen was detected in 29 (30.2%) BAL fluid samples, with a sensitivity of 95.0% (95% confidence interval [CI], 90.6% to 99.4%) and a specificity of 86.8% (95% CI, 80.1% to 93.8%). The ICT was easy to perform and revealed unequivocal and reproducible results. No interference was observed with high cell counts, red blood cells, or elevated protein levels. Four out of 10 false-positive readings occurred in samples with S. pneumoniae counts below the 10(4) CFU/ml threshold limit of pneumonia. In BAL fluid samples obtained after pneumococcal bacteremia, positive test results were found for up to 35 days after bacteremia. The ICT test applied to BAL fluid specimens is reproducible and accurate in the diagnosis of pneumococcal antigen. Further studies are required to establish the impact of the ICT on patient care.     

Rapid identification of pneumococcal antigenes in urines by the Now Streptococcus pneumoniae Binax test

Streptococcus pneumoniae is responsible for many infectious conditions but probably with an underestimated incidence especially because of the fragility of the bacteria. The present study has evaluated a new test which detects a pneumococcal antigen in urine (Now S.p Binax). Urine samples from 181 children and 40 adults have been tested. All the patients presented with typical clinical signs of pneumococcal infection. Sensitivity = 91.7 %; specificity = 54.2 %; positive predictive value = 50 %; and negative predictive value = 92.9 % have been observed. Although the sensitivity and specificity were lower than those announced by the manufacturer, the test is easy to handle and provides a rapid argument for the diagnosis of pneumococcal infection, especially in the case of invasive infections like meningitis and bacteraemia.     

New technique (the NOW test) for rapid detection of Streptococcus pneumoniae in the nasopharynx

Although the NOW test was originally introduced as a rapid pneumococcal antigen detection test for use with urine samples, it was successfully adapted to nasopharyngeal samples in the present study. The sensitivity, specificity, positive predictive value, and negative predictive value of the test were 92.2, 97.7, 95.9, and 95.5%, respectively. These results demonstrate that nasopharyngeal colonization with Streptococcus pneumoniae can be documented within 15 min of sample collection.     

Performance of the Binax NOW Streptococcus pneumoniae urinary antigen assay for diagnosis of pneumonia in children with underlying pulmonary diseases in the absence of acute pneumococcal infection

The performance of the Binax NOW immunochromatographic test for detecting Streptococcus pneumoniae antigen in urine specimens from 103 children presenting underlying pulmonary diseases with no recent pneumococcal infection was assessed. Our data indicate that this assay is unlikely to be useful for discriminating between children with and without pneumococcal pneumonia.     

Characterization of a new mouse model of empyema and the mechanisms of pleural invasion by Streptococcus pneumoniae

Although empyema affects more than 65,000 people each year in the United States and in the United Kingdom, there are limited data on the pathogenesis of pleural infection. We investigated the pathogenesis of empyema using animal and cell culture models of Streptococcus pneumoniae infection. The pathological processes during the development of empyema associated with murine pneumonia due to S. pneumoniae (strain D39) were investigated. Lungs were examined using histology, and pleural fluid and blood bacterial colony-forming units, cytokine levels, and cellular infiltrate were determined over time. Bacterial migration across mesothelial monolayers was investigated using cell culture techniques, flow cytometry, and confocal microscopy. After intranasal inoculation with 10(7) S. pneumoniae D39 strain, mice developed pneumonia associated with rapid bacterial invasion of the pleural space; raised intrapleural IL-8, VEGF, MCP-1, and TNF-α levels; and caused significant intrapleural neutrophilia followed by the development of fibrinous pleural adhesions. Bacterial clearance from the pleural space was poor, and in vitro assays demonstrated that S. pneumoniae crossed mesothelial layers by translocation through cells rather than by a paracellular route. This study describes key events during the development of S. pneumoniae empyema using a novel murine model of pneumonia-associated empyema that closely mimics human disease. The model allows for future assessment of molecular mechanisms involved in the development of empyema and evaluation of potential new therapies. The data suggest that transmigration of bacteria through mesothelial cells could be important in empyema development. Furthermore, upon entry the pleural cavity offers a protected compartment for the bacteria.     

Detection of Streptococcus pneumoniae carriage by the Binax NOW test with nasal and nasopharyngeal swabs in young children

The rapid detection of carriage of Streptococcus pneumoniae could assist in the management of pneumococcal infection, such as acute otitis media. We evaluated the reliability of the Binax NOW test in the exclusion and detection of pneumococcal carriage by nasal samples from 139 children and using nasopharyngeal samples from 250 children (aged 6–35 months) with respiratory infection with or without acute otitis media. The Binax NOW test results were compared with culture-based detection of carriage of S. pneumoniae. The Binax NOW test from the nasal samples had a sensitivity of 95%, a specificity of 78%, and the positive and negative predictive values were 83 and 93%, respectively; and for the nasopharyngeal samples the corresponding numbers were 88%, 95%, 96%, and 87%. When rapid knowledge of the carriage status of S. pneumoniae is needed, the Binax NOW test is a reliable method for the exclusion of carriage using nasal sampling, and in the detection of carriage using nasopharyngeal sampling.     

Evaluation of a rapid immunochromatographic test for detection of Streptococcus pneumoniae antigen in urine samples from adults with community-acquired pneumonia

Streptococcus pneumoniae is the most common cause of community-acquired pneumonia but is undoubtedly underdiagnosed. Isolation of S. pneumoniae from blood is specific but lacks sensitivity, while isolation of S. pneumoniae from sputum may represent colonization. We evaluated a new immunochromatographic test (NOW S. pneumoniae urinary antigen test; Binax, Portland, Maine) that is simple to perform and that can detect S. pneumoniae antigen in urine within 15 min. Urine samples from 420 adults with community-acquired pneumonia and 169 control patients who did not have pneumonia were tested. Urine from 315 (75%) of the pneumonia patients and all controls was tested both before and after 25-fold concentration, while the remaining 105 samples were only tested without concentration. S. pneumoniae urinary antigen tests were positive for 120 (29%) patients with pneumonia and for none of the controls. Of the urine samples tested with and without concentration, 96 were positive, of which 6 were positive only after concentration. S. pneumoniae antigen was detected in the urine from 16 of the 20 (80%) patients with blood cultures positive for S. pneumoniae and from 28 of the 54 (52%) patients with sputum cultures positive for S. pneumoniae. The absence of S. pneumoniae antigen in the urine from controls suggests that the specificity is high. Concentration of urine prior to testing resulted in a small increase in yield. The NOW S. pneumoniae urinary antigen test should be a useful adjunct to culture for determining the etiology of community-acquired pneumonia in adults.     

Evaluation of a rapid immunochromatographic test in the diagnosis of dengue fever

Serology is the mainstay of diagnosis in Dengue virus infection. Various rapid tests for antibody detection have been developed. They can prove to be important diagnostic tools especially in the field set up due to technical simplicity. We evaluated a Rapid immunochromatographic assay The rapid test was performed on acute phase sera collected from patients suspected to be suffering from Dengue fever/DHF. These samples were then tested by Dengue Duo Capture ELISA and compared The rapid test showed a good sensitivity for the detection of secondary dengue infection and thus can be a good screening tool.     

Performance of an immunochromatographic test for the rapid diagnosis of malaria

The immunochromatographic test (ICT) for the rapid diagnosis of malaria has been marketed for several years. In a study in which three Centres of Tropical Medicine participated and data were pooled, performance of the test varied considerably when comparing the results between each centre. The sensitivity of ICT in 2,343 patients tested in our services was 100% and the specificity 99.74%. Moreover, two patients with a positive ICT would initially have been missed by expert microscopy, with Plasmodium falciparum malaria being confirmed microscopically some hours later. The principal reasons for the better performance of the test in our series appear to be blood collection in EDTA vials and considerable experience with handling and interpreting the ICT test.     

Modified TB rapid test by proteinase K for rapid diagnosis of pleural tuberculosis

The diagnosis of pleural tuberculosis continues to be a challenge due to the low sensitivity of traditional diagnostic methods. Better and more rapid tests are needed for diagnosis of pleural TB. In this study, pleural fluids were tested with rapid test to determine Mycobacterium tuberculosis (MTB antigen). Affinity chromatography was used to purify specific polyclonal antibodies against MTB antigen. Pleural samples after decontamination were treated with proteinase K. Rapid test for pleural fluids was prepared by specific antibody. Rapid test was performed on 85 pleural fluid patients. The patients had a mean age of 46.55 ± 15.96 years and 38 were men. The performance of rapid test, using proteinase K, was found to be the most impressive: sensitivity 93%, specificity 94%, PPV 90%, and NPV 96% compared with adenosine deaminase test (ADA), PCR, smear, and culture. The present study did demonstrate that modified TB rapid test can substantially improve the diagnosis of extrapulmonary TB.     

Assessment of a rapid immunochromatographic test for the diagnosis of norovirus gastroenteritis

Noroviruses are the leading cause of acute gastroenteritis in people of all ages. Since the viruses are highly infectious, rapid and early diagnosis is important to prevent and control the disease. The present study aimed to evaluate the commercial immunochromatographic test RIDA? QUICK Norovirus for the detection of norovirus in stool samples from patients with acute gastroenteritis in Thailand. As compared with reference RT-PCR results, the RIDA? QUICK Norovirus assay provided a sensitivity of 48.2 and 83.3% with a specificity of 87.5%. False positive results were observed in 12.5% of norovirus-negative stool samples. Based on commercial quantitative real-time RT-PCR, the RIDA? QUICK Norovirus assay revealed a highly significant association, p-value <0.001, and good agreement (kappa?=?0.6). The assay could detect norovirus in stool samples ranging from 3.22?×?10(6) to 3.26?×?10(8) copies/ml. False negative results occurred in the stool samples containing 5.9?×?10(6) copies/ml of norovirus GI or 1.85?×?10(4)?-?4.28?×?10(5) copies/ml of GII. The immunochromatographic RIDA? QUICK Norovirus assay may be useful for rapid screening of norovirus infections in patients with acute gastroenteritis in both developed and developing countries where the RT-PCR method has not been established for routine diagnosis.     

Evaluation of the immunochromatographic CORIS Giardia-Strip test for rapid diagnosis of Giardia lamblia

The aim of this study was to evaluate the performance of the CORIS Giardia-Strip test (CORIS Bioconcept, Gembloux, Belgium) as a rapid initial method for the routine diagnosis of giardiasis. Compared to a commercial ELISA-coproantigen test (ProSpect Giardia-ELISA-microplate assay; Remel, Lenexa, KS, USA), the commercial strip test had a sensitivity of 58%, a specificity of 99%, a positive predictive value of 93% and a negative predictive value of 93% (n=158). These results are comparable to those obtained using microscopy of direct wet-mounted stool. Since the CORIS Giardia-Strip test is simpler to perform, it can replace direct wet-mounted stool microscopy for the rapid diagnosis of giardiasis; however, its sensitivity is inferior to that of other immunochromatographic antigen detection tests and fresh stool samples are required for its use. Nevertheless, the results suggest that a positive CORIS Giardia-Strip test outcome does not need confirmation, while samples with negative results should be re-examined using another, more sensitive, test.     

Usefulness of urinary antigen detection by an immunochromatographic test for diagnosis of pneumococcal pneumonia in children

We evaluated an immunochromatographic assay detecting pneumococcal antigen in urine samples from children diagnosed with pneumococcal pneumonia. The sensitivity and specificity of the immunochromatographic test with nonconcentrated urine (NCU) were 86.7 and 62.9%, respectively; with concentrated urine (CU), they were 100 and 11.7%, respectively. Pneumococcal antigen was also detected in 42.5% of NCU and 87.1% of CU samples from nasopharyngeal carriers. This is a nonspecific test for the diagnosis of pneumococcal pneumonia in children, particularly the very young.     

Rapid and simple diagnosis of Chlamydophila pneumoniae pneumonia by an immunochromatographic test for detection of immunoglobulin M antibodies

To evaluate a newly developed immunochromatographic test (the MySet test) for the detection of Chlamydophila pneumoniae-specific immunoglobulin M antibodies, the results obtained by the MySet test were compared with those obtained by two serological tests. The sensitivity and specificity of the MySet test were 100% and 92.9%, respectively. The MySet test is rapid and simple to use and is thought to be a useful tool for the selection of appropriate antibiotic therapy.     

A convenient immunochromatographic test strip for rapid diagnosis of yellow head virus infection in shrimp

A simple yellow head virus (YHV) “strip test” was developed using monoclonal antibody Y19 (against the p20 structural protein) conjugated with colloidal gold as the detector antibody. Rabbit anti-recombinant p20 (rp20) protein antibody was used as a capture antibody at the test line (T) and goat anti-mouse IgG antibody (GAM) was used as the capture antibody at the control line (C). The ready-to-use strip was housed in a plastic case for convenient application and stored in the desiccated plastic bag. A sample volume of 100 μl of either haemolymph or gill or appendage homogenates in application buffer was applied to the sample chamber at one end of the strip and allowed to flow by chromatography through the nitrocellulose membrane to the other end. In test samples containing YHV, the virus would bind to colloidal gold conjugated monoclonal antibody and the resulting complex would be captured by the rabbit anti-rp20 antibody at the test line to give a reddish-purple band. Any unbound monoclonal antibody conjugated with colloidal gold moved across the test line to be captured by the GAM to form a band at the control line (C). In the sample without YHV or below the limit of detection for the kit, only the control line was demonstrated. This method was about 500 times less sensitive than that of one-step RT-PCR, but slightly more sensitive than dot blotting. Therefore, it could be used for primary screening of individual shrimp or pooled shrimp samples to confirm high levels of YHV infection or YHV disease outbreaks. This kit can be used to detect gill associated virus (GAV) infection as well since the monoclonal antibody used in this kit cross-reacted well with GAV. The beneficial features of this kit are that simple, convenient, and rapid results that can be obtained without the requirement of sophisticated tools or special skills.     

Identification of Streptococcus pneumoniae by the Phadebact coagglutination test.

The Phadebact Pneumococcus Test is a coagglutination slide test for the serological identification of Streptococcus pneumoniae. Of 200 alpha-hemolytic streptococcal isolates, coagglutination test results agreed with those of optochin susceptibility and bile solubility in 189 cases, 105 of which were identified as S. pneumoniae by all three methods. The Phadebact test was 100% (113 of 113) sensitive and 98% (85 of 87) specific and was more sensitive than counterimmunoelectrophoresis in detecting the presence of pneumococcal antigen in cerebrospinal fluid. In fluids seeded with known amounts of pneumococcal antigen, it consistently detected lower levels than did counterimmunoelectrophoresis. The test provides a rapid and simple method for the definitive identification of S. pneumoniae.