[Usefulness of urinary antigen and sputum Gram stain for rapid diagnosis of pneumococcal respiratory infections].

We evaluated the usefulness of a rapid urinary antigen detection kit (Binax NOW) to detect Streptococcus pneumoniae in the early diagnosis of pneumococcal respiratory tract infections in 313 patients with presumptive respiratory tract infections. We compared results of this test with those of sputum Gram staining. Urinary antigen and sputum Gram staining were respectively positive in 37 and 36 of 57 patients with pneumococcal respiratory infections. The urinary antigen showed moderate positive rate of 64.9% and low false positive rate of 2.3%. The sputum Gram staining also showed moderate positive rate of 64.3% and low false positive rate of 3.5%. Pneumococcal antigen was more frequently detected in patients with severe pneumococcal infections (6/6) than those with mild (5/10) and moderate (26/41) infections. Of the 9 patients who had received antibiotics before testing, antigen was detected in 8 but positive results of sputum Gram stain were in 4. In conclusion, urinary antigen test is a useful test for early diagnosis of pneumococcal respiratory infections especially in adult patients with moderate or severe infections for whom demonstrative results of a sputum Gram stain is unavailable, even after commencement of antibiotic treatment.

[Pathogenesis of beta-lactam-resistant Haemophilus influenzae isolated from sputum].

Haemophlus influenzae persists in the respiratory tract and sometimes causes respiratory tract infections. To evaluate the pathogenesis of beta-lactam-resistant Haemophilus influenzae, we classified 193 Haemophilus influenzae strains isolated from sputum of patients with respiratory tract disease in 24 beta-lactamase positive (BLP) strains, 65 beta-lactamase negative ampicillin resistant (BLNAR) strains and 104 beta-lactamase negative ampicillin sensitive (BLNAS) strains and reviewed the pathogenesis of the strains. The pathogenesis of the strains was evaluated as definite pathogen, presumptive pathogen, colonization and contamination. It was judged to be the definite pathogen that many bacteria isolated from high quality sputum of the patients with respiratory tract infections. Presumptive pathogen was considered to be the bacteria provided from the patient with respiratory infections when the quality of the sputum or quantity of bacteria did not satisfy superscription basis. We considered the bacteria to be colonization or contamination isolated from patients without infections. The breakdown of definite pathogen/presumptive pathogen/colonization/contamination in each by groups was BLP (8/4/8/4), BLNAR (26/14/15/10), BLNAS (36/20/31/17). The ratio of definite or presumptive pathogen was 50% in BLP, 62% in BLNAR and 54% in BLNAS and the significant difference was not recognized in these. Pathogenesis of beta-lactam-resistant Haemophilus influenzae is estimated to be equal with beta-lactam-sensitive Haemophilus influenzae.

[Sudden onset of EDTA-dependent pseudothrombocytopenia in a patient scheduled for open heart surgery].

A 60-year-old woman scheduled for mitral and aortic valve replacement had sudden onset of thrombocytopenia without clinical symptoms. The platelet count was found to decrease after the sampling. Microscopic examinations confirmed platelet aggregations. Changing anticoagulant added to blood samples from EDTA to heparin resolved such platelet aggregations. This phenomenon was diagnosed as demonstrating EDTA-dependent pseudothrombocytopenia and the operation was performed as scheduled without platelet transfusion. Postoperative course was almost uneventful and the patient was discharged on 26th day after surgery. EDTA-dependent pseudothrombocytopenia must be ruled out when patients have thrombocytopenia without certain causes such as infections, drugs, or autoimmune diseases.