Japanese Journal of Infectious Diseases
Online ISSN : 1884-2836
Print ISSN : 1344-6304
ISSN-L : 1344-6304
Volume 65, Issue 6
Displaying 1-19 of 19 articles from this issue
Invited Review
  • Toshihiro Mita, Kazuyuki Tanabe
    Article type: Invited Review
    2012 Volume 65 Issue 6 Pages 465-475
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Malaria is a protozoan disease transmitted by the bite of the Anopheles mosquito. Among five species that can infect humans, Plasmodium falciparum is responsible for the most severe human malaria. Resistance of P. falciparum to chloroquine and pyrimethamine/sulfadoxine, conventionally used antimalarial drugs, is already widely distributed in many endemic areas. As a result, artemisinin-based combination therapies have been rapidly and widely adopted as first-line antimalarial treatments since the mid-2000s. Recent population and evolutionary genetic analyses have proven that the geographic origins of parasite lineages resistant to the conventional drugs are considerably limited. Almost all resistance emerged from either Southeast Asia or South America. The Greater Mekong subregion in Southeast Asia is probably the most alarming source of resistance, from which P. falciparum resistant to chloroquine and pyrimethamine/sulfadoxine dispersed to Africa. The emergence of artemisinin resistance has also recently been confirmed in the Greater Mekong. The WHO Global Malaria Programme has recently launched a “Global Plan for Artemisinin Resistance Containment,” which aims to prevent the spread of artemisinin resistance while also stopping the emergence of novel resistance. However, an inadequate understanding of a mechanism of artemisinin resistance and the lack of reliable genetic markers to monitor artemisinin resistance make it difficult to survey the spread of resistance. Elucidation of such markers would substantially contribute to the design of an effective policy for the containment of artemisinin resistance.
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Review
  • Ying-Hui Shi
    Article type: Review
    2012 Volume 65 Issue 6 Pages 476-482
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Hepatitis B virus (HBV) has been classified into 10 genotypes (A–J) according to genome sequence divergence. HBV genotypes have a distinct geographical distribution. As chronic HBV infection is endemic in the Asian region, genotypes B and C prevail there, and genotypes A and D are mainly found in the western world and Europe. Genotypes A, B, C, and D have been studied most extensively. In Europe and Asia, most patients with genotypes A and B have acute hepatitis B; however, some mutants may tend to cause fulminant hepatitis B. Many studies have indicated that the severity and outcomes of chronic hepatitis B infections are more serious in patients with genotypes C and D than in those with genotypes A and B. Cirrhosis and hepatocellular carcinoma (HCC) are more frequently diagnosed in carriers of genotypes C and D than in those of genotypes A and B. Accumulating evidence indicated that higher plasma HBV DNA levels, infection with HBV genotype C, as well as mutations at 1653T, 1753V, and A1762T/G1764A are independently associated with the risk of HCC in Asian men. However, the therapeutic responses differ with regard to the different HBV genotypes. For example, the response to interferon-α treatment in patients with genotypes A and B was better than that in patients with genotypes C, D, and mixed genotypes. Some studies have shown seroconversion after treatment, i.e., genotypes A and C may switch to genotypes D and B, respectively. Some reports indicated a correlation between the emergence of the hepatitis B e antigen-negative variant in patients with genotypes C and D and worsening of liver injury without sustained response. In order to provide better treatment options for these poorly responding patients, further studies, e.g, novel immunomodulatory therapies, are required. Many studies have shown that HBV genotypes have remarkable clinical and epidemical differences; however, HBV sub-genotypes, mixed genotype infections, and the effect of different genotypes on the treatment of HBV infections require further studies.
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Original Article
  • Taketo Otsuka, Hassan Zaraket, Koyata Fujii, Yasuko Masuda, Kenichi Ko ...
    Article type: Original Article
    2012 Volume 65 Issue 6 Pages 483-488
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Sado Island in Japan is an area with low antimicrobial pressure. A total of 41 community-onset methicillin-resistant Staphylococcus aureus (MRSA) isolates were obtained from pediatric outpatients and healthy children between August 2009 and January 2012, and genotyping and antimicrobial susceptibility testing of the MRSA isolates were performed. Additionally, the sources of MRSA isolated from healthy 1-month-old neonates were assessed. All isolates were negative for the Panton-Valentine leukocidin genes. Our data showed a lower prevalence of staphylococcal cassette chromosome (SCC)mecII on Sado Island (31.7% in total and 46.7% in healthy carriage) than that in the other areas of Japan, suggesting that a low level of antimicrobial use may be related to a low SCCmecII carriage rate in the community. To our knowledge, this is the first report of sequence type (ST)81/SCCmecIVg strains as well as the novel ST strain (ST2180/SCCmecIVa) in Japan. In addition, we detected an arginine catabolic mobile element (ACME)-arcA-positive ST764/SCCmecIIa clone that could disseminate successfully in the community. Intrafamilial transmission was observed in neonates identified with the SCCmecIV MRSA strains, and these strains were genetically typed as community-associated MRSA; the transmission routes of the remaining SCCmecIIa MRSA (genetically typed as healthcare-associated MRSA) strains could not be defined. In this study, we have shown that multiple MRSA strains can circulate in a community even under low antimicrobial pressure.
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  • Hideki Kusunoki, Kazu Okuma, Isao Hamaguchi
    Article type: Original Article
    2012 Volume 65 Issue 6 Pages 489-494
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    For national regulatory testing in Japan, the Lowry method is used for the determination of total protein content in vaccines. However, many substances are known to interfere with the Lowry method, rendering accurate estimation of protein content difficult. To accurately determine the total protein content in vaccines, it is necessary to identify the major interfering substances and improve the methodology for removing such substances. This study examined the effects of high levels of lactose with low levels of protein in freeze-dried, cell culture-derived Japanese encephalitis vaccine (inactivated). Lactose was selected because it is a reducing sugar that is expected to interfere with the Lowry method. Our results revealed that concentrations of ≥0.1 mg/mL lactose interfered with the Lowry assays and resulted in overestimation of the protein content in a lactose concentration-dependent manner. On the other hand, our results demonstrated that it is important for the residual volume to be ≤0.05 mL after trichloroacetic acid precipitation in order to avoid the effects of lactose. Thus, the method presented here is useful for accurate protein determination by the Lowry method, even when it is used for determining low levels of protein in vaccines containing interfering substances. In this study, we have reported a methodological adjustment that allows accurate estimation of protein content for national regulatory testing, when the vaccine contains interfering substances.
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  • Murat Sayan, Caner Cavdar, Cengiz Dogan
    Article type: Original Article
    2012 Volume 65 Issue 6 Pages 495-501
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    The aim of this study was to assess the frequencies and patterns of naturally occurring genotypic resistance to nucleos(t)ide analogues (NUCs) and typical hepatitis B surface antigen (HBsAg) amino acid substitutions in naive hemodialysis (HD) patients with chronic hepatitis B. In order to achieve this, the genotypic resistance to NUCs and HBsAg amino acid substitutions were classified into primary/compensatory resistance mutation and antiviral drug-associated potential vaccine-escape mutation (ADAPVEM)/typical HBsAg amino acid substitution, respectively. Direct sequencing of polymerase (pol) gene of hepatitis B virus (HBV) was performed on DNA samples obtained from 248 HBsAg-positive Turkish patients. Overall, 38% (n = 94) of HBsAg-positive HD patients had detectable HBV DNA in their serum. Naturally occurring primary and compensatory resistance mutations to NUCs were detected in 30% (n = 28) and 52% (n = 49) of HD patients, respectively. However, 6 types of ADAPVEMs and 48 types of typical HBsAg amino acid substitutions were found in 10.6% (n = 10) and 46% (n = 43) of the HD patients, respectively. Our study suggests that every HD patient diagnosed with chronic hepatitis B, who is a potential candidate for NUCs treatment, should also be monitored for the baseline pol gene sequence changes before the initial treatment, for a more effective management of future treatment options. Further, a relatively higher frequency of ADAPVEMs variants needs to be addressed as a public health problem.
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  • King Ting Lim, Chew Chieng Yeo, Zarizal Suhaili, Kwai Lin Thong
    Article type: Original Article
    2012 Volume 65 Issue 6 Pages 502-509
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Staphylococcus aureus is a persistent human pathogen responsible for a variety of infections ranging from soft-tissue infections to bacteremia. The objective of this study was to determine genetic relatedness between methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) strains. We isolated 35 MRSA and 21 MSSA strains from sporadic cases at the main tertiary hospital in Terengganu, Malaysia, screening them for the presence of virulence genes. Their genetic relatedness was determined by accessory gene regulator (agr) types, PCR-restriction fragment length polymorphism (RFLP) of the coa gene, pulsed-field gel electrophoresis (PFGE), S. aureus protein A (spa), and multilocus-sequence typing (MLST). We found that 57% of MRSA and 43% of MSSA strains harbored enterotoxin genes. The majority (87.5%) of the strains were agr type I. PCR-RFLP and PFGE genotyping of the coa gene revealed that MRSA strains were genetically related, whereas MSSA strains had higher heterogeneity. The combined genotype, MLST-spa type ST239-t037, was shared among MRSA and MSSA strains, indicating that MRSA strains could have evolved from MSSA strains. Two combined MLST-spa types were present in MRSA strains, whereas 7 different MLST-spa types were detected in MSSA strains, including 2 combined types (ST779-t878 and ST1179-t267) that have not been reported in Malaysia. In conclusion, enterotoxin genes were more prevalent in MRSA than in MSSA strains in the Terengganu hospital. The MSSA strains were genetically more diverse than the MRSA strains.
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  • Xiao-Bing Zhang, Shuang-Jiang Yu, Jun-Xiao Yu, Ya-Li Gong, Wei Feng, F ...
    Article type: Original Article
    2012 Volume 65 Issue 6 Pages 510-515
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    The incidence of candidemia has increased in recent years. This paper reports a retrospective analysis of 270 cases of candidemia occurring from January 2000 to December 2009 at a teaching hospital in China. Demographic and clinical data were collected from patient medical records and the hospital's laboratory database. Candida albicans (35.9%) was the most prevalent species isolated, followed by C. tropicalis (21.8%) and C. glabrata (13.0%). Antifungal susceptibilities to fluconazole, flucytosine, and amphotericin B tended to decline over the study period. The most common risk factors were the presence of central venous catheters, endotracheal intubation, hypoproteinemia, renal failure, and concurrent bacteremia. In the 181 (67.0%) patients who died during hospitalization, endotracheal intubation, hypoproteinemia, and C. albicans were the major factors associated with mortality. This study highlights the importance of considering the possibility of invasive Candida infection in patients exposed to these risk factors.
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  • Hiroyuki Ueno, Yoshihiko Yamamoto, Akiko Yamamichi, Koji Kikuchi, Sumi ...
    Article type: Original Article
    2012 Volume 65 Issue 6 Pages 516-521
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Streptococcus agalactiae (group B streptococcus; GBS) is a common cause of neonatal sepsis and meningitis. Intrapartum antibiotic prophylaxis is effective in reducing neonatal GBS disease. Penicillin is recommended for intrapartum antibiotic prophylaxis; however, other antibiotics are administered to pregnant women with penicillin allergy. Serotyping and antibiotic susceptibility testing were performed on 376 GBS isolates collected from vaginal swabs in Saitama City. Of the 376 isolates, 328 (87.2%) were obtained from obstetrics and gynecology clinics. Although approximately 80% of the isolates (299/376) were from women of reproductive age (age, 15–49 years), no definite information on their pregnancy status was obtained. The most frequent serotype was V (19.1%) followed by Ib (18.6%), III (16.2%), VI (14.9%), and Ia (14.6%). None of the isolates were resistant to penicillins and cephalosporins. Isolates that were resistant to erythromycin (12.8%), clindamycin (9.0%), ofloxacin (19.4%), levofloxacin (18.4%), and tetracycline (46.5%) were detected. There was a high prevalence of resistance to erythromycin (39.3%) and clindamycin (27.9%) in serotype III. In addition, almost all serotype Ib isolates were resistant to ofloxacin and levofloxacin (both, 91.4%). Pulsed-field gel electrophoresis analysis on certain GBS isolates (serotype Ib, III, and V) indicated that there was genetic diversity among the resistant isolates obtained from a limited area of Japan. In conclusion, present intrapartum antibiotic prophylaxis with penicillins would be effective in Japan; however, performing susceptibility testing before administering other antibiotics is important in order to ensure activity against the relevant isolate.
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  • Norihito Tarumoto, Yuki Kinjo, Keigo Ueno, Akiko Okawara, Hiroshi Wata ...
    Article type: Original Article
    2012 Volume 65 Issue 6 Pages 522-526
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Candida albicans is a major cause of invasive fungal infections. Mortality attributable to candidemia is very high, even when patients are treated with adequate antifungal agents. Therefore, it is important to investigate the mechanisms of immune response to C. albicans. Invariant natural killer T (iNKT) cells, innate lymphocytes that express an invariant T cell receptor α chain, participate in the response to various microbes, including two fungal pathogens, Aspergillus fumigatus and Cryptococcus neoformans. However, it is unknown whether iNKT cells play a role in the immune response to C. albicans. In this study, we have investigated the role of iNKT cells in the host defense against systemic C. albicans infection in mice. We compared the survival and fungal clearance between control mice and Jα18KO mice, which specifically lack iNKT cells, after intravenous C. albicans infection. There was no difference in the survival and fungal burden in the kidneys of the control and Jα18KO mice. Furthermore, production of inflammatory cytokines in several organs during C. albicans infection did not significantly differ between these two groups. These results suggest that iNKT cells play a minor role in controlling systemic C. albicans infections in mice.
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  • Chaiyaporn Chaisatit, Chanwit Tribuddharat, Chaiwat Pulsrikarn, Surang ...
    Article type: Original Article
    2012 Volume 65 Issue 6 Pages 527-534
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    We assessed contamination by antibiotic-resistant bacteria in chicken meat obtained from supermarkets in Bangkok, Thailand. The prevalence of Salmonella enterica and Escherichia coli was 18.7% (14/75) and 53% (106/200), respectively. Most probable number (MPN) analysis showed that 56.7% of the samples (34/60) were in violation of the limit of allowable coliform bacteria in chicken meat, for which the maximum is 46,000 MPN/g. Multidrug-resistant phenotypes of both S. enterica and E. coli were found. The presence of class 1 integrons was demonstrated by polymerase chain reaction (PCR) and dot-blot hybridization. PCR showed that class 1 integrons were present in 42.9% (6/14) and 37.7% (40/106) of S. enterica and E. coli isolates, respectively. Resistance genes identified in this study were aadA2, aadA4, aadA22, and aadA23 (for aminoglycoside resistance); dfrA5 (for trimethoprim resistance), and lnuF (for lincosamide resistance). Four S. enterica isolates underwent multilocus sequence typing and the results were sequence type (ST) 50, ST 96, ST 1543, and ST 1549, which matched well with strains from many countries and reflected an international spread. Our study revealed that class 1 integrons have spread into community sources and might play an important role in horizontal antibiotic resistance gene transfer.
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Short Communication
  • Hiroto Akaike, Naoyuki Miyashita, Mika Kubo, Yasuhiro Kawai, Takaaki T ...
    Article type: Short Communication
    2012 Volume 65 Issue 6 Pages 535-538
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Macrolide-resistant Mycoplasma pneumoniae is emerging in several countries, and it is mainly observed in children. To our knowledge, we conducted the first multicenter prospective epidemiological study of macrolide-resistant M. pneumoniae in order to investigate regional differences in the susceptibility of macrolide-resistant M. pneumoniae to antibacterial agents. The in vitro activities of 11 antimicrobial agents against macrolide-resistant M. pneumoniae isolates from 5 different areas of Japan were investigated. Among 190 M. pneumoniae isolates from pediatric patients, 124 (65.2%) isolates showed macrolide resistance and possessed an A2063G transition in domain V of the 23S rRNA. These isolates showed high resistance to erythromycin, clarithromycin, and azithromycin with minimum inhibitory concentrations (MICs) ≥16 μg/ml. Conversely, quinolones such as garenoxacin, moxifloxacin, tosufloxacin, and levofloxacin exhibited potent antimycoplasmal activity. No regional differences were observed with respect to the MICs among the 5 areas in Japan.
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  • Fazel Pourahmad, Hasan Shojaei, Parvin Heidarieh, Azardokht Khosravi, ...
    Article type: Short Communication
    2012 Volume 65 Issue 6 Pages 539-541
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Herein, we report repeated isolation of Mycobacterium europaeum from the sputum samples of an Iranian human immunodeficiency virus-infected patient and a cystic fibrosis patient with chronic pulmonary disease. To our knowledge, this is the first isolation of M. europaeum from human clinical specimens in Asia to be reported.
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  • Kentaro Tohma, Akira Suzuki, Kanako Otani, Michiko Okamoto, Nao Nukiwa ...
    Article type: Short Communication
    2012 Volume 65 Issue 6 Pages 542-544
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Influenza has a significant impact on public health when a natural disaster occurs during the influenza season. However, the epidemiological characteristics of influenza following natural disasters have not been well documented due to the difficulty of implementing laboratory-based influenza surveillance in such situations. The Great East Japan Earthquake occurred on March 11, 2011, when influenza was already circulating. Since routine influenza surveillance was not performed in Miyagi Prefecture, we initiated an ad hoc laboratory-based monitoring system immediately after the earthquake. From March 15 to May 19, we tested 277 samples for influenza virus collected around Sendai City and from evacuation centers in Miyagi Prefecture. Influenza A (H3N2) was detected in 112 cases, influenza A (H1N1) 2009 in one case, and influenza B in 92 cases. The H3N2 virus was dominant until the 14th week. However, a sudden increase in the number of influenza B cases occurred after schools were reopened. According to phylogenetic analysis, a major clade switch of the H3N2 virus took place after the earthquake. The Yamagata lineage of influenza B was detected in one patient from western Japan, indicating the importing of viruses into the affected area.
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  • Ayaka Shima, Atsushi Hinenoya, Masahiro Asakura, Akira Nagita, Shinji ...
    Article type: Short Communication
    2012 Volume 65 Issue 6 Pages 545-547
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    In the present study, we examined the prevalence of Providencia spp. strains among children with diarrhea in Japan. We developed a Providencia genus-specific polymerase chain reaction (PCR) method, and the specificity and sensitivity was evaluated to be 100% with various bacterial strains including 7 genera and 13 species. Five of 345 samples (1.4%) were positive by PCR using a Providencia genus-specific primer targeting the 16S rRNA gene. The single species Providencia rettgeri was isolated from 4 stool samples of children with diarrhea. The prevalence of Providencia spp. in children with diarrhea in Japan is lower than that previously reported for Japanese travelers abroad with diarrhea.
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  • Kisei Minami, Yasuhiro Shoji, Masashi Kasai, Yoshifumi Ogiso, Tomohiko ...
    Article type: Short Communication
    2012 Volume 65 Issue 6 Pages 548-550
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Extended-spectrum β-lactamase (ESBL)-producing-Enterobacteriaceae strains were detected in 12% (6 out of 50) of fecal samples collected from the inpatients of a Japanese pediatric hospital. All the ESBLs belonged to the CTX-M-1 group. The proportion of carriage of ESBL producers was higher among patients who had received antibiotics within the past 3 months and among those who had cardiologic diseases.
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  • Tetsuo Asai, Mototaka Hiki, Kotaro Baba, Masaru Usui, Kanako Ishihara, ...
    Article type: Short Communication
    2012 Volume 65 Issue 6 Pages 551-552
    Published: 2012
    Released on J-STAGE: November 21, 2012
    JOURNAL FREE ACCESS
    Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is mainly associated with swine and is capable of causing zoonotic infections. The methicillin-resistant S. aureus (MRSA) multilocus sequence type (ST) 398 of swine origin is predominant in Europe and North America, whereas ST9 is predominant in Asia. To evaluate the possible emergence of MRSA in swine, we examined the ST and spa type of 15 methicillin-susceptible S. aureus (MSSA) isolates obtained from swine in 8 different prefectures from north to south Japan between 2003 and 2009. Sequence analyses revealed that 6 porcine MSSA isolates belonged to ST398; 6 to ST9; and 1 each to ST5, ST97, and ST705. Of the 6 MSSA ST398 strains, 4 were classified as spa type t034. This study illustrated that there is a reservoir in Japanese swine of livestock-associated MSSA types.
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Laboratory and Epidemiology Communications
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