MRSA has been a major causative agent of nosocomial infection. However, recently MRSA has become increasingly isoated from community-associated infections. We summarized here up to date information about community-associated MRSA (C-MRSA) infections and characteristics of C-MRSA strains based on molecular analysis. By using the SCCmec typing, strong evidence was provided for the independent derivation of healthcare-associated MRSA and C-MRSA clones.

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Influenza C virus (Inf. C) is one of pathogens of human respiratory tract infection and prevalent throughout the world at an early stage in life. However, Inf. C has been isolated only accidentally and there have been few reports on its clinical and epidemiological features. From November 1999 to March 2000, Inf. C was isolated from clinical specimens (throat swabs) of 4 pediataric patients with respiratory tract illness at Hiroshima Prefectural Hospital and was isolated in 4 peditaric patients at the other medical institutions in Hiroshima prefecture. There were no differences in clinical features including duration of illness, duration of fever, maximum body temperature between 4 patients with Inf. C infection and patients with influenza A (H1N1 and H3N2) and influenza B infection from 1992 to 2000. We investigated geographical distribution of patients with inf. C infection and analyzed for antigenic characteristics with a set of monoclonal antibodies against hemagglutinin-esterase glycoproteins. The data suggested that at least two antigenically different inf. C prevalented in a region during winter from 1999 to 2000.

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A reassortant influenza A H1N2 virus was isolated from a returning traveller arriving at Nagoya International Airport, Japan from Indonesia in May, 2002.
A Hemagglutination inhibition test revealed that the virus was similar to a vaccine strain of A/NewCaledonia/20/99. A phylogenetic analysis demonstrated that the virus forms a cluster with other influenza A H1N2 viruses isolated in other countries. The reassortment event was theoretically assumed to have occurred between the 1999/2000 and 2000/2001 influenza seasons. Neither A H1N2 nor A H3N1 virus was detected from 256 isolates of AH1 or 177 of AH3 influenza viruses isolated in Aichi Prefecture, Japan between the 1999/2000 and 2001/2002 influenza seasons. This finding suggests the importance of influenza surveillance at an airport quarantine office to detect promptly a novel influenza virus penetrating to Japan.

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The aims of this study are to investigate the antimicrobial susceptibility of bacteria isolated from children and clarify the risk factors for the carriage of the resistant strains. We examined the minimum inhibitory concentrations (MICs) of antimicrobial agents against 949 strains of Streptcoccus pneumoniae (S. pneumoniae) and 791 strains of Haemophilus influenzae (H. influenzae) isolated at our department between September, 2001 and May, 2003. Of those, 226 S. pneumoniae strains and 115 H. influenzae strains were analysed for the resistance genes. Also we retrospectively reviewed the profiles of 1, 359 patients with either S. pneumoniae, H. influenzae, or both in nasopharynx. From the view point of MICs, PSSP strains were 185 (19%), PISP strains were 443 (47%), and PRSP strains were 321 (34%) in 949 S. pneumoniae strains, and BLNAS strains were 545 (69%), low-BLNAR strains were 104 (13%), BLNAR strains were 81 (11%), and BLPAR strains were 61 (8%) in 791 H. influenzae strains. The results of gene analysis showed that all resistant strains by MICs such as PISP, PRSP, BLNAR, and BLPAR had resistant genes and that 55% of and 21% of susceptible strains of S. pneumoniae (PSSP) and H. influenzae (BLNAS), respectively, had resistant genes. From the investigation for profiles of 1, 359 patients, age less than 3 years old, day nursery, and use of antimicrobial agents in last 3 month, seemed to be the risk factors for carriage of resistant strains. To prevent the resistant bacteria from disseminating we should re-consider how to use the antimicobial agents and nurse the young children.

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Identification of pathogens in childhood community-acquired pneumonia (CAP) is not easy. However, it is believed that nasopharyngeal colonization of pathogenic bacteria leads to childhood CAP, so the etiology is inferred by the isolates obtained from nasopharynx of children with CAP.
Among the pathogens of childhood CAP, Streptococcus pneumoniae (SP) is the most important agent and macrolides resistant SP (MRSP) is increasingly reported.
We investigated the characterization of the mechanism of macrolide resistance in isolates of MRSP by the presence of the ermB gene or the mefA gene and clindamycin (CLDM) resistance. In addition, we also assessed the efficacy of azithromycin (AZM) in children with CAP who were isolated MRSP from nasopharynx.
During a 6 month period between January and June in 2002, children with CAP who were treated with a 3 day regimen of AZM and isolated SP from nasopharynx were enrolled. Clinical outcome was based on assessment of fever on the fourth day of treatment. MIC measurements were obtained by broth microdilution and interpreted according to NCCLS criteria.
53 patients were enrolled and MRSP were isolated in 41 children. Of 41 MRSP isolates, 25 isolates were identified CLDM resistance. The AZM MIC₉₀ of CLDM resistant MRSP isolates was 128μg/ml. On the other hand, that of CLDM sensitive MRSP isolates was 8μg/ml. However, AZM was effective in 20 children isolated CLDM resistant MRSP and 15 out of 16 children isolated CLDM sensitive MRSP.
On this background, despite high rates of MRSP in Japan, AZM continues to be clinically effective for the treatment of childhood CAP.

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Since October 2000, Mycoplasma pneumonia has been a recurring epidemic in Japan. To become clear the importance of Mycoplasma pneumoniae infection in children, we investigated cross-sectionally M. pneumoniae infection by serology in the hospitalized children age under seven years with acute pneumonia retrospectively reviewing pediatric patients of the four studies about lower respiratory tract infection which we had been treated during 2001 to 2003.
Firstly, we found M. pneumoniae infection in 75 patients (33.8%) among a total of 222 patients with asthma exacerbation and acute pneumonia in 2001. Second, we had evaluated a total of 46 hospitalized children with acute pneumonia for M. pneumoniae infection in November 2002 and 18 patients (39.1%) were found. Thirdly, we found M. pneumoniae infection in 8 patients (34.8%) among 23 patients with respiratory syncitial virus and acute pneumonia age under two years during October 2002 to April 2003. Fourthly, we found M. pneumoniae infection in 19 patients (35.8%) among 53 patients with asthma exacerbation and acute pneumonia during January from June in 2003.
Even only among the patients age under two years M. pneumoniae infection was found to be 24.3% (16/70), 27.8% (5/8), 34.8% (8/23) and 33.3% (7/21), respectively.
These findings demonstrate that M. pneumoniae is common pathogen of acute pneumonia even in infants and young children under Mycoplasma epidemic. Not only typical bacteria and but also M. pneumoniae should be considered as important pathogens in the treatment of acute pneumonia ininfants and young children under Mycoplasma epidemic.

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Previously, we found that collaboration of reactive nitrogen intermediates (RNI) and free fatty acids (FFA) plays crucial roles in the expression of macrophage (MΦ) antimicrobial activity against Mycobacterium tuberculosis (MTB). Phospholipase A₂ (PLA₂) families hydrolyze phospholipids and release FFA from their sn-2 position. In the present study, we examined profiles of the mRNA expression of PLA₂ families by MΦs stimulated with MTB by using RT-PCR method, and the following results were obtained. First, the expression of type IV cytosolic PLA₂ (cPLA₂), which is highly specific to arachidnic acid moiety, was significantly up-regulated by MTB stimulation of MΦs. Second, the expression of type IIa secretory PLA₂ (sPLA₂) was not observed for MΦs with or without MTB stimulation.Third, the profile of mRNA expression of type V sPLA₂ was nearly the same as that of type IV cPLA₂ for MΦs before and after MTB stimulation. These findings suggest that type IV cPLA₂ and type V sPLA₂ both play important roles in the FFA-mediated Mφ Cap antimicrobial activity against MTB organisms.

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Resistance genes were determinded for 81 strains of Streptococcus pneumoniae isolated from Ehime University hospital, during 2002 and 2003 by various clinical material. In penicillin-binding proteins of mutation, there were 74 strains; pbp2x mutation 23 strains (28.4%), pbp2b mutation one strain (12%), pbp1a+pbp2x mutations 5 strains (6.2%), pbp2x+pbp2b mutations 18 strains (22.2%) and all mutations 27 strains (33.3%). As for the result of macrolide resistance genes, there were 67strains; mefA gene 20 strains (24.7%), ermB gene 46 strains (56.8%) and both gene one strain (1.2%).In the analysis of gyrA gene and parC gene, 3 strains (3.7%) had both gene mutations, and 26 strains (32.1%) had only parC gene mutation. There was more of an increase than before in isolates, two or more mutation strains with PBPs gene, ermB gene holding strains and the levofloxacin resistance strain. These results suggest that the gyrA gene or parC gene mutation strains hold PBPs gene mutation and macrolide resistance genes in a high rate, and there will be more drug resistance in the future.

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A 53-year-old male was admitted to our hospital complaining of high fever with chillness, cough and dyspnea after traveling to Arizona in the United States. The chest X-ray films taken on admission showed consolidation in the right middle lung field and bilateral nodular shadows. The laboratory data revealed an increase in white blood cell counts with eosinophilia, and a rise in erythrocyte sediment rate and serum C-reactive protein. The biopsied lung specimen by video-assisted thoracoscopic surgery showed granulomatous inflammation consisting of eosinophils and giant cells. In addition, typical spherules filled with endopores were detected in the specimen. The diagnosis of primary pulmonary coccidioidomycosis was made. After the treatment of a three months' regimen with itraconazole at the daily dosage of 200mg, the patient's symptoms, laboratory data and radiological findings markedly improved.

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[in Japanese]

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