Streptococcus pneumoniae isolated in various parts of Japan from a total of 590 patients with identified or putative pneumococcal infections were typed using type-specific antisera during the three years from April, 1980 to March, 1983.The results obtained were as follows:1) The 590 identified isolates belonged to 43 Danish types and the rank order of isolates was: Type 3 (12.7%), 19 F (9.3%), 23 F (6.8%), 6 B (5.9%), 6 A (5.9%), 14 (4.9%), 11 A (4.1%), 19 A (3.7%), 9 V (3.6%), 22 F (3.1%) and others.2) A total of 430 isolates (72.9%) belonged to one of the 23 pneumococcal types to be included in the commercial 23-valent pneumococcal polysaccharide vaccine and 160 isolates (27.1%) were types not be included in the vaccine. The rates of isolation of vaccine-type pneumococci were 76.2% for blood, CSF, transtracheal aspirate (TTA) and others, 66.9% for sputum and throat swabs, 90.5% for middle ear effusions, 79.1% for meningitis and septicemia, 66.9% for respiratory tract infections, and 89.3% for otitis media.When the nonvaccine-type 6 A which is known to cross-react with type 6 B antibody in humans is included, the total number of vaccine-type pneumococcal isolates was 465 (78.8%), and the rates of isolation of vaccine-type pneumococci were 83.3% for blood, CSF, TTA and others, 73.3% for sputum and throat swabs, 91.9% for middle ear effusions, 87.0% for meningitis and septicemia, 71.9% for respiratory tract infections, and 92.0% for otitis media.It seems that there is no variation depending on the distribution by type of the pneumococcal isolates according to age and region.
The Showa disk susceptibility test using two penicillinase-resistant penicillins, oxacillin and methicillin, was evaluated to discriminate between the strains of Staphylococcus aureus resistant to methicillin (MRSA) and those susceptible (MSSA) in the multi-center trials. The study included 651 clinical isolates of S. aureus, comprising of 329 MRSA and 322 MSSA isolates. The inhibitory zone diameters by Showa disks to oxacillin and methicillin highly correlated with minimum inhibitory concentrations (MICs) determined by standard agar dilutions with 0.961 and 0.930 correlation coefficients, respectively. Of 651 duplicate MIC determinations, 79.9% (oxacillin) and 80.3% (methicillin) were within +/- 1 log2 dilutions with each other. When Showa oxacillin and methicillin disks were incubated at 35 degrees C, sensitivity and specificity of oxacillin to detect MRSA were 95.4% and 98.1%, and those of methicillin were 94.8% and 95.2%. When tested on agar plates supplemented with 5% NaCl, sensitivity and specificity markedly improved to > 97%. Also, when incubated at 30 degrees C, sensitivity and specificity became to nearly 100%. Of 329 MRSA isolates, the interpretive criteria combined with incubation at 30 degrees C and testing onto 5% NaCl supplemented agar plates could correctly identify 324 (98.5%) and 329 (100%) isolates, respectively. In conclusion, when the Showa oxacillin and methicillin disk susceptibility tests were employed exactly according to the manufacturer's instruction, the test performances to detect MRSA were enough reliable to screen MRSA isolates in clinical microbiology laboratories.
The antibiotic activity demonstrated by P. aeruginosa (Bacillus pyocyaneus) has been reported more than one hundred years ago by Emmerich et al (1899). Studies on such bacterial interference between P. aeruginosa and other pathogenic bacteria or fungi have not been extensively reported in recent years. In this paper, we report on the anti MRSA activity and anti Candida activity demonstrated by clinical isolates of P. aeruginosa (34 strains). The antibiotic activity was tested by reversed agar plate method, as previously reported, and the degree of the activity was expressed as the diameter of the zone of growth inhibition. The stability of both anti MRSA activity and anti Candida activity was evaluated at the time after 24 and 48-hr incubation. Also the effect of agar plate with or without 5% sheep blood on antibiotic activity was evaluated. Strong anti MRSA activity and anti Candida activity was shown at the time after 24-hr incubation. At the time after 48-hr incubation, anti MRSA activities were significantly suppressed but anti Candida activities were persisted. The inhibitory activity was correlated with dye production of P. aeruginosa. Some strains having non or weak dye production, showed the inhibitory activity by 48-hr incubation. Result from these strains without suppression of anti Candida activity by additional blood may suggest that the existence of a new factor produced by P. aeruginosa. Because of frequent isolation of MRSA or Candida from clinical materials, we must consider bacterial flora and bacterial interference against pathogenic bacteria at the time of the antibiotic choice for the patients infected or colonized with P. aeruginosa.
