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We analyzed non-serotype b encapsulated Haemophilus influenzae (non-b Hi) isolated from pediatric patients at Chiba Children's Hospital during 2000-2012. Among 3,532 clinical isolates of H. influenzae, there were 57 (1.6%) strains of non-b Hi, 152 (4.3%) of serotype b H. influenzae (Hib), and 3,323 (94.1%) of non-typeable H. influenzae (NTHi). Fifty-seven strains of non-b Hi were serotyped useing the slide agglutination test and PCR. Twenty-nine strains were identified as type e (Hie) and 28 as type f (Hif), and the results according to the slide agglutination test and PCR were completely identical. Whereas 52 of 57 strains (91.2%) were isolated from respiratory specimen, only one Hif strain (1.8%) was isolated from a sterile site. There were 47 (82.4%) β-lactamase-non-producing ampicillin (ABPC)-sensitive strains (BLNAS), 5 (8.8%) β-lactamase-producing strains (BLP), and only 1 (1.8%) β-lactamase-non-producing ABPC-resistant strain (BLNAR). Thus the frequency of non-b Hi was lower than that of Hib. The source of non-b Hi was similar to that of NTHi, which was mainly isolated from respiratory specimen. Antimicrobial resistant pattern of non-b Hi was different from that of Hib in which the frequency of BLP was relatively high, and NTHi in which that of BLNAR was high. An increase of invasive H. influenzae infections caused by NTHi, Hie, and Hif was reported in the countries where Hib vaccine had been widely used. Because it is assumed that invasive non-Hib infection will be predominant in the near future in Japan, serotyping of invasive strains is crucial. Continuous monitoring of distribution of non-b Hi in the clinical isolates of H. influenzae is also important.

Haemophilus influenzae type b (Hib) vaccine has been included in the national Immunization Program in more than 120 countries around the world and its effectiveness and safety have been confirmed. In Japan, Hib vaccine was recently licensed in December 2008. Because it has included in the category of voluntary vaccine and the burden of out-of-pocket expense is a major concern for caregivers, payment coverage through the local government funded by the temporal national budget has been initiated since November 2010. It is important to make an effort to fill the "vaccine gap" between Japan and other developed countries and increase a vaccine coverage rate including Hib vaccine to decrease vaccine preventable diseases in Japanese children.

We investigated the antibody response to a 23-valent pneumococcal polysaccharide vaccine (23PSV), in 151 patients (average age: 70 years old) with chronic respiratory disease. Serotype-specific IgG antibodies to 4 pneumococcal capsular polysaccharides (6B, 14, 19F, and 23F) were analyzed by ELISA before, and one month after, 23PSV vaccination in all patients. Patients showed a significant increase in specific IgG levels to Streptococcus pneumoniae after 23PSV vaccination (5.5 times-20.9 times). Even patients aged over 80, patients with respiratory failure, and patients receiving corticosteroid therapy developed a significant immunologic response to 23PSV. Local pain or induration occurred in 9.1-14.3% and fatigue or chills occurred in 0.7-6.5% of patients. All adverse reactions disappeared in 2 or 3 days and there was no severe adverse events. Further studies are needed to confirm the exact protective antibody level and to examine the decline of antibody level after vaccination.

A portion of the neuS gene concerning Escherichia coli K1, was amplified by the PCR to detect the K1 antigen among extraintestinal infection with E. coli. The correlation between K1 antigen and O:H serotype was investigated. The predominant serotypes were O7:H-, O16:H6, O18ac:H7 from cerebrospinal fluid with meningitis, O16:H6 from blood with septicemia, O1 : H7, O7:H-, O16:H6, O18ac:H7, O75 : H- from urine with cystitis. The same O:H serotypes tended to be found frequently irrespective of source. K1 antigen was found O1:H7, O7:H-, O16:H6, O18ac:H7, and almost all the strains possessed to H6 or H7.

One hundred and one strains of enterotoxemic Escherichia coli (ETEEC) O-group 139 isolated from swine with edema disease were investigated for their adherence to HEp-2 cells in the presence of D-mannose. All strains adhered in large numbers to the cells (21 to 60 bacteria/cell). No correlation was found between the presence of F107 fimbria on the organisms and the adherence to the cells. Adhesion-inhibition tests showed that anti-K12 serum inhibited the adhesion ETEEC O-group 139 (an inhibition rate of 63 to 65%), but anti-F107 or anti-O139 sera did not. These results indicate that the capsular K12 antigen may be one of the pathogenic factors of ETEEC O-group 139.

Eight strains of Staphylococcus epidermidis were isolated from clinical specimens and were subjected to the tests for encapsulation, slime-production, mouse-virulence, capsular-typing and adherence to the plastic surface, the renal cells and the bladder epithelial cells. With the intraperitoneal injection of these strains into mice, three encapsulated strains were observed in mouse-virulent, while two slime-producing and three unencapsulated strains were mouse-avirulent. In ultra-thin sections of mouse-virulent strains, capsules were demonstrated by electron microscopy, however no capsule was seen around the walls of mouse-avirulent strains. On the other hand, slime-producing strains were shown to have higher adherence rate to plastic surface, compared to encapsulated strains. The direct adherence rate to the bladder epithelial cells was greater in the encapsulated strains than the slime-producing strains, although there was no difference to the renal cells. Also, cell suspension containing 10(7) colony forming units of these strains were injected intravenously or intravesically into mice. Of these encapsulated strains showed kidney and bladder lodgement with in 28 and 21 days after intravesical injection, respectively, although slime-producing and unencapsulated strains could only be obtained for 7 days in the kidney and 3 days in the bladder. However, there was no difference in the internal organs lodgement of the strains after intravenous injection into mice. These experimental results suggested that the encapsulation of the strains would be an important factor for bladder lodgement, however, significant effects were not observed with the slime-producing and unencapsulated strains.

In this study, role of capsular polysaccharide (CPS) and lipopolysaccharide (LPS) of Klebsiella pneumoniae was investigated in experimental mice pneumonia model. Inoculation with K. pneumoniae mucoid strain DT-S into mice lung induced expansive, voluminous lethal pneumonia characterized with thickening of the alveolar septa caused by infiltration of inflammatory cell and packing of bacteria within alveolar spaces. On the other hand, mice lung inoculated with K. pneumoniae DT-X, which was non-mucoid mutant isolated from DT-S during natural passage, showed infiltration of inflammatory cell into alveolar spaces but there was no death of mice during the course of this pneumonia. Inoculation of CPS 100 micrograms of DT-S strain into mice lung induced lesser extent of accumulation of inflammatory cell than that of LPS 4 micrograms of this strain. Stimulation of alveolar and peritoneal macrophage with CPS, even at a concentration of 100 micrograms/ml, induced weaker Interleukin-1 (IL-1) activity than stimulation with LPS 4 micrograms/ml. These results suggest that since CPS of K. pneumoniae DT-S encapsulate bacteria including LPS, CPS may inhibit chemotaxis of inflammatory cell and IL-1 production of macrophage to be induced by LPS during course of pneumonia. It is speculated that existence of CPS have important role in modulating host response to bacterial LPS, and this effect of CPS may be related with difference of pathological findings of lung and lethality between K. pneumoniae DT-S and DT-X.

The phagocytic and killing activities of human pulmonary alveolar macrophages (PAM) and polymorphonuclear leukocytes (PMN), and superoxide (O2-) production in phagocytizing PAM and PMN were studied by using a strongly and weakly virulent strains of Cryptococcus neoformans (C. neoformans) in mice. The strongly virulent strain was encapsulated with a thick capsule while the other had a thin one. The phagocytic and killing activities of PAM and PMN against the strongly virulent strain were lower than against the weakly virulent one. There was no significant difference between PAM and PMN in terms of phagocytic or killing activities and O2- production. It seems likely that O2- plays no defensive role in the intracellular killing of C. neoformans by PAM and PMN because no correlation was found between the killing activity and O2- production. These results indicate that human PAM and PMN play an effective role in host defense against the weakly virulent strain of C. neoformans encapsulated with a thin capsule but are not effective against the strongly virulent strain encapsulated with a thick capsule.