Comparative molecular and microbiological diagnosis of 19 infective endocarditis cases in which causative microbes were identified by PCR-based DNA sequencing from the excised heart valves.

Infective endocarditis (IE) is traditionally diagnosed by microbiological analysis of blood cultures, following which therapeutic antibiotics are chosen based on antimicrobial sensitivity tests. However, such conventional techniques do not always lead to an accurate etiological diagnosis. Recently, PCR analysis of the 16S rRNA gene has been employed to identify organisms isolated from excised heart valves. In this study, we analyzed 19 valve samples from patients with confirmed IE, as identified by Duke's criteria. Using broad-range PCR amplification, followed by direct gene sequencing, pathological agents were identified in all samples. Although blood cultures yielded negative results in 4 cases, PCR analysis of valve samples showed positive identification of causative organisms. In 3 cases, there was a difference between blood culture and PCR in identification of pathological agents, which are likely to be misidentified by the conventional method based on the phenotypic database. Postoperative antibiotics were chosen considering the severity of lesions and the results of PCR, Gram staining, and valve cultures. All patients were cured without relapse. The broad-range PCR method was therefore beneficial for the management of IE because it enabled us to identify pathogens directly from the site of infection, even organisms that were difficult to culture or likely to be misidentified by the conventional culture method. Identification of the agents provided precise knowledge of the microbiological spectrum involved in the cases of IE.

Prediction of the pathogens that are the cause of pneumonia by the battlefield hypothesis.

Commensal organisms are frequent causes of pneumonia. However, the detection of these organisms in the airway does not mean that they are the causative pathogens; they may exist merely as colonizers. In up to 50% cases of pneumonia, the causative pathogens remain unidentified, thereby hampering targeting therapies. In speculating on the role of a commensal organism in pneumonia, we devised the battlefield hypothesis. In the "pneumonia battlefield," the organism-to-human cell number ratio may be an index for the pathogenic role of the organism. Using real-time PCR reactions for sputum samples, we tested whether the hypothesis predicts the results of bacteriological clinical tests for 4 representative commensal organisms: Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas spp., and Moraxella catarrhalis. The cutoff value for the organism-to-human cell number ratio, above which the pathogenic role of the organism was suspected, was set up for each organism using 224 sputum samples. The validity of the cutoff value was then tested in a prospective study that included 153 samples; the samples were classified into 3 groups, and each group contained 93%, 7%, and 0% of the samples from pneumonia, in which the pathogenic role of Streptococcus pneumoniae was suggested by the clinical tests. The results for Haemophilus influenzae, Pseudomonas spp., and Moraxella catarrhalis were 100%, 0%, and 0%, respectively. The battlefield hypothesis enabled legitimate interpretation of the PCR results and predicted pneumonia in which the pathogenic role of the organism was suggested by the clinical test. The PCR reactions based on the battlefield hypothesis may help to promote targeted therapies for pneumonia. The prospective observatory study described in the current report had been registered to the University Hospital Medical Information Network (UMIN) registry before its initiation, where the UMIN is a registry approved by the International Committee of Medical Journal Editors (ICMJE). The UMIN registry number was UMIN000001118: A prospective study for the investigation of the validity of cutoff values established for the HIRA-TAN system (April 9, 2008).

[Examination about utility of a Streptococcus pneumoniae capsular antigen swiftness search kit urine in a pneumonia patient].

We investigated the usefullness of Binax NOW urine antigen test, an immunochromatographic assay that binds any soluble Streptococcus pneumoniae antigen (C polysaccharide) for the diagnosis of penumoniae form September 2003 to March 2005. We used 372 samples form the patinets with pneumoniae diagnosed for blood or sputum cultuter or gram-stained sputum smear. Out of 24 culture positive specimens, Binax NOW urine antigen test, showed positive in 18 (75%) specimens. The sensitivity of sputum and blood culture was 71.7% and 83.3%, respectively. Binax NOW urine antigen test was seemed false positives in 55 samples, false negatives in 6 samples. The specificity of Binax NOW urine antigen test was evaluated 84.1%. Overall agreement among tests was 83.6%. When compared to culture, false negative urine antigen may be the result of colonizing S. pneumoniae in sputum or pneumonia caused by an agent other than S. pneumoniae. CRP values for cases were both urine antigen and culture were positive ranged from 40 mg/dl to 10 mg/dl while urine antigen and culture negative cases were predominantly less than 10 mg/dl. Positive blood and pleural fluid culture cases were consistently associated with strongly positive urine antigen tests. Non-agreement between urine antigen, culture, and microscopy may be the result of specimen quality, labile nature of S. pneumoniae and antimicrobial therapy.

[Comparison of a rapid antigen test and cultures for diagnosis of meningitis in children].

Fourteen pediatric patients diagnosed as bacterial meningitis between August 1997 and April 2002 were enrolled in this study. Both rapid antigen detection test, Slidex Meningite 5 Kit (Biomerieux) and culture were performed using cerebrospinal fluids (CSF). H. influenzae was isolated from 11 samples and was the most frequently isolated bacteria, followed by S. pneumoniae from 4 samples and enteric bacteriae from 2 samples. Five out of six samples with positive result by culture were also positive by the rapid antigen test. Gram-negative rod was identified in smear specimens of CSF from all these 5 samples. Significance of the rapid antigen test should be recognized under drug resistance of those bacteriae are increasing.