Naruhiko Ishiwada

Detection of influenza virus RNA by reverse transcription-PCR and proinflammatory cytokines in influenza-virus-associated encephalopathy.

Eleven children with acute encephalopathy associated with an influenza virus infection were treated during the 1997–1998 influenza season. Reverse transcription‐polymerase chain reaction (RT‐PCR) assay was used to detect the viral genome in peripheral blood and cerebrospinal fluid (CSF) samples. The results were compared with those of control influenza patients without neurological complications. Viral RNA was detected only in the peripheral blood mononuclear cells of one patient with influenza‐virus‐associated encephalopathy (1 of 9; 11%) and in the CSF of another patient (1 of 11; 9%). RT‐PCR was negative in the blood of all the controls, but the percentage of RT‐PCR‐positive samples in the two groups was not significantly different. Cytokines and soluble cytokine receptors in plasma and CSF were then quantified using an enzyme‐linked immunosorbent assay. The CSF concentrations of soluble tumor necrosis factor receptor‐1 were elevated in two patients and interleukin‐6 (IL‐6) was elevated in one patient with influenza‐virus‐associated encephalopathy. On the other hand, the plasma concentrations of IL‐6 were elevated in four of nine patients. The number of encephalopathy patients who had elevated plasma concentrations of IL‐6 100 pg/ml was significantly higher than that of controls (P = .01). In conclusion, the infrequent detection of the viral genome in the CSF and blood showed that direct invasion of the virus into the central nervous system was an uncommon event. Proinflammatory cytokines and soluble cytokine receptors may mediate the disease. The high plasma concentration of IL‐6 could be an indicator of the progression to encephalopathy. J. Med. Virol. 58:420–425, 1999.

The burden of childhood pneumonia in the developed world: A review of the literature

Background: Estimates of the disease burden from childhood pneumonia are available for most developed countries, but they are based mainly on models. Measured country-specific pneumonia burden data are limited to a few nations and differ in case definitions and case ascertainment methods. This review describes pneumonia disease burden in developed countries. Methods: We reviewed studies describing childhood pneumonia incidence in North America, Europe, Australia, New Zealand and Japan. Available estimates suggest that each year in developed countries there are up to 2.6 million cases of pneumonia, including 1.5 million hospitalized cases and around 3000 pneumonia deaths (compared with approximately 640 annual deaths from meningitis) in children <5 years of age. Results: Data to inform policy decisions would be improved by information on burden and etiology of severe pneumonia, population-based incidence of ambulatory visits and hospitalizations and prevalence of complications and sequelae.

Nationwide population-based surveillance of invasive pneumococcal disease in Japanese children: Effects of the seven-valent pneumococcal conjugate vaccine.

BACKGROUND In Japan, the seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2010. PCV13 has replaced PCV7 since November 2013. METHODS The effectiveness of PCV7 in protecting against invasive pneumococcal disease (IPD) in children aged <5 years was evaluated in a nationwide active population-based surveillance of IPD in 2008-2013 in 10 prefectures in Japan. RESULTS 1181 cases were identified; 711 pneumococcal strains were analyzed for serotyping and antimicrobial resistance. Compared with the baseline IPD incidence (25.0 per 100,000), a 98% decline in IPD caused by PCV7 serotypes was found after the introduction of PCV7. This was partially offset by an increased incidence of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes, resulting in a 57% decline in overall IPD incidence. Absolute increases in the incidence rates of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes were 2.1 and 2.8 per 100,000 during the study period, respectively. The proportion of meropenem-nonsusceptible strains, especially with serotypes 19A and 15A, increased significantly after PCV7 introduction. CONCLUSIONS Our data confirmed a 98% decline in IPD incidence caused by PCV7 serotypes in children aged <5 years and serotype replacement after PCV7 introduction. This shows the importance of continuing surveillance of serotypes responsible for IPD and their antimicrobial resistance in Japan.

Incidence of childhood pneumonia and serotype and sequence-type distribution in Streptococcus pneumoniae isolates in Japan.

The 7-valent pneumococcal conjugate vaccine (PCV7) is reported to decrease the incidence of community-acquired pneumonia (CAP) in children. To determine the annual incidence of CAP before the introduction of PCV7, we counted the number of children hospitalized with CAP between 2008 and 2009 in Chiba City, Japan. We investigated serotype and multilocus sequence typing (MLST) for Streptococcus pneumoniae isolates in CAP cases. The annual incidence of hospitalized CAP in children aged <5 years was 17.6 episodes/1000 child-years. In 626 episodes, S. pneumoniae was dominant in 14.7% and 0.8% of sputum and blood samples, respectively. The most common serotypes were 6B, 23F and 19F. The coverage rates of PCV7 were 66.7% and 80% in sputum samples and blood samples, respectively. MLST analysis revealed 37 sequence types. Furthermore, 54.1% of the sputum isolates and 40% of the blood isolate were related to international multidrug-resistant clones.

The incidence of pediatric invasive Haemophilus influenzae and pneumococcal disease in Chiba prefecture, Japan before and after the introduction of conjugate vaccines.

The Haemophilus influenzae type b (Hib) vaccine and the heptavalent pneumococcal conjugate vaccine (PCV7) were introduced in Japan in 2008 and 2010, respectively. In 2011, immunization with these two vaccines was encouraged throughout Japan through a governmental program. Children treated in Chiba prefecture for culture-proven invasive H. influenzae disease (IHiD) and invasive Streptococcus pneumoniae disease (IPD) were identified in a prefectural surveillance study from 2008 to 2013. The incidence rate ratio (IRR) and its confidence interval (CI) were calculated to compare the 3 years before and after governmental financial support for vaccination. The average number of IHiD and IPD cases among children <5 years of age in 2011-2013 decreased 84% (IRR: 0.16, 95% CI: 0.09-0.26, p<0.0001) and 51% (IRR: 0.49, 95% CI: 0.37-0.63, p<0.0001) compared with those occurring in 2008-2010. The most common non-PCV7 serotype encountered in 2011 and 2013 was 19A. After governmental subsidization of Hib and PCV7 vaccination, IHiD and IPD decreased in Chiba prefecture, Japan. Continuous surveillance is necessary to determine the effectiveness of these two vaccines and for detection of emerging invasive serotypes.

First adult case of Helicobacter cinaedi meningitis

Helicobacter cinaedi, a gram-negative spiral bacillus that inhabits the intestinal tracts of rodents and primates, is associated with gastroenteritis in humans. H. cinaedi infection has been commonly reported in immunocompromised individuals such as human immunodeficiency virus-infected patients, but rarely in immunocompetent individuals. Prior contact with animals has attracted attention as a possible source of H. cinaedi infection. We report a case of meningitis in an immunocompetent 34-year-old woman who had daily contact with a kitten for a month. She developed acute headaches, fevers, and chills. Neurological examination revealed neck stiffness and her cerebrospinal fluid (CSF) exhibited polymorphonuclear pleocytosis and a decreased concentration of glucose. Blood and CSF cultures were negative; however, the pathogen responsible for her condition was identified as H. cinaedi by polymerase chain reaction in CSF. This is the first adult case of meningitis caused by H. cinaedi. Thus, this bacillus should be considered a possible causative agent of bacterial meningitis in healthy adults.

The incidence of pediatric invasive pneumococcal disease in Chiba prefecture, Japan (2003–2005)

OBJECTIVES The purpose of the study is to evaluate the incidence, spectrum of clinical manifestations and outcome of invasive pneumococcal disease (IPD) in children in Chiba prefecture, Japan. METHODS To determine the precise incidence of IPD in Chiba prefecture, we implemented a retrospective survey of the period from 2003 to 2005. A written questionnaire was sent to 45 hospitals that have pediatric wards, and information was obtained from all hospitals. The questionnaire included the clinical diagnosis, patients age, underlying disease, prognosis and antimicrobial susceptibility of the isolated strains. RESULTS During the 3 study years, 130 patients were diagnosed with IPD. The mean annual incidence rates of IPD among children <2 and <5 years were 19.5-23.8 and 12.6-13.8 per 100,000, respectively. Among 130 patients with systemic infection, 66 patients had bacteremia, 39 had pneumonia and 16 had meningitis. Five patients had neurological sequelae and 2 patients died. Seventy-four out of 115 isolates (64.3%) exhibited resistance to penicillin G. CONCLUSIONS The annual incidence of pediatric IPD has remained constant during the study period. Two-third of isolated strains were at least partially resistant to penicillin G. Establishment of appropriate antibiotic therapy against IPD due to penicillin-resistant strains and the introduction of pneumococcal conjugate vaccines are emergent issues in Japan.

Low opsonic activity to the infecting serotype in pediatric patients with invasive pneumococcal disease.

Serotype-specific protective immunity in pediatric patients with invasive pneumococcal disease (IPD) has not been fully investigated. To determine the protective immunity to the infecting serotype, the serotype-specific immunoglobulin G (IgG) levels and opsonization indices (OIs) were examined in 24 Japanese pediatric patients whose serum was collected within one month of an IPD episode between May 2008 and June 2011. The median age (range) of IPD patients was 17 (10-108) months and 63% were boys. In all 17 patients tested, the levels of serotype-specific IgG to the infecting serotype were higher than 0.2 μg/ml, but the OIs to the infecting serotype were <8. The avidities of 19F- or 6B-specific IgG in patients with levels higher than 5.0 μg/ml, but with undetectable OIs, were confirmed to be lower than those in patients with high OIs. Our data demonstrated that although the levels of serotype-specific IgG to the infecting serotype were higher than 0.2 μg/ml in sera of pediatric patients with IPD, the OIs were low one month after the IPD episode. Low opsonic activities in these patients may, in part, be explained by the low avidity of serotype-specific IgG.

Recurrent meningitis associated with a petrous apex cephalocele.

We present the case of a 6-year-old girl with recurrent bacterial meningitis and cerebrospinal fluid (CSF) rhinorrhea associated with a petrous apex cephalocele (PAC). We diagnosed her by means of three-dimensional computed tomography (CT) and heavily T2-weighted magnetic resonance imaging (MRI). Petrous apex cephaloceles are usually an asymptomatic incidental finding in adults; however, they should be considered as a possible cause of CSF rhinorrhea, otorrhea, and recurrent meningitis in children. (J Child Neurol 2005;20:168—170).

New Successful Treatment with Disinfectant for Atopic Dermatitis

For the treatment of atopic dermatitis, a variety of therapies are used including folk medicine. At present, there is no single treatment which is effective to cure the symptoms of atopic dermatitis completely in all patients. We are drawing attention to the high isolation rate of Staphylococcus aureus when starting disinfectant treatment combined with topical steroid therapies for the purpose of killing S. aureus. As a result, we examined many patients in whom almost a complete remission was obtained even after short periods of therapy, though it had been difficult to obtain improvement by conventional treatments. In many patients, IgE values and reagin antibody titer decrease dramatically soon after starting treatment. As a disinfectant, 10% povidone-iodine solution was used. We investigated also the effect of iodine contained in the povidone-iodine solution on the thyroid gland.