Guidelines for the Management of Respiratory Infectious Diseases in Children in Japan 2022

The members of the Japanese Society for Pediatric Infectious Diseases and the Japanese Society of Pediatric Pulmonology have developed Guidelines for the Management of Respiratory Infectious Diseases in Children with the objective of facilitating appropriate diagnosis, treatment and prevention of respiratory infections in children. The first edition was published in 2004 and the fifth edition was published in 2022. The Guideline 2022 consists of 2 parts, clinical questions and commentary, and includes general respiratory infections and specific infections in children with underlying diseases and severe infections. This executive summary outlines the clinical questions in the Guidelines 2022, with reference to the Japanese Medical Information Distribution Service Manual. All recommendations are supported by a systematic search for relevant evidence and are followed by the strength of the recommendation and the quality of the evidence statements.

Acute and Postacute Clinical Characteristics of Coronavirus Disease 2019 in Children in Japan

BACKGROUND

The clinical features of coronavirus disease 2019 (COVID-19) in children have been changing because of the emergence and rapid spread of variants of concern (VOC). The increase in cases infected with VOC has brought concern with persistent symptoms after COVID-19 in children. This survey aimed to analyze the clinical manifestations and persistent symptoms of pediatric COVID-19 cases in Japan.

METHODS

We analyzed the clinical manifestations of pediatric COVID-19 cases reported between February 2020 and April 2022 in Japan, using a dedicated database updated voluntarily by the members of the Japan Pediatric Society. Using the same database, we also analyzed persistent symptoms after COVID-19 in children who were diagnosed between February 2020 and November 2021.

RESULTS

A total of 5411 and 1697 pediatric COVID-19 cases were included for analyzing clinical manifestations and persistent symptoms, respectively. During the Omicron variant predominant period, the percentage of patients with seizures increased to 13.4% and 7.4% in patient groups 1-4 and 5-11 years of age, respectively, compared with the pre-Delta (1.3%, 0.4%) or Delta period (3.1%, 0.0%). Persistent and present symptoms after 28 days of COVID-19 onset were reported in 55 (3.2%).

CONCLUSIONS

Our survey showed that the rate of symptomatic pediatric COVID-19 cases increased gradually, especially during the Omicron variant predominant period, and a certain percentage of pediatric cases had persistent symptoms. Certain percentages of pediatric COVID-19 patients had severe complications or prolonged symptoms. Further studies are needed to follow such patients.

Clinical evaluation of a new rapid immunochromatographic test for detection of Bordetella pertussis antigen

A more rapid and less complicated test to diagnose pertussis is required in clinical settings. We need to detect Bordetella pertussis, which mainly causes pertussis, as early as possible, because pertussis is more likely to become severe in infants, and people around them can easily become a source of infection due to its strong infectivity. Nevertheless, methods that can detect B. pertussis rapidly and efficiently are lacking. Therefore, we developed a new immunochromatographic antigen kit (ICkit) for the early diagnosis of pertussis. The ICkit detects B. pertussis antigens in a nasopharyngeal swab without equipment and provides the result in about 15 min with a simple procedure. Additionally, a prospective study to evaluate the ICkit was conducted in 11 medical institutions, involving 195 cases with suspected pertussis. Compared with the real-time polymerase chain reaction (rPCR), the sensitivity and specificity of the ICkit were 86.4% (19/22) and 97.1% (168/173), respectively. The ICkit detected the antigen in both children and adults. Furthermore, the ICkit detected the antigen until the 25th day from the onset of cough, when rPCR detected the antigen. Thus, the ICkit demonstrated a high correlation with rPCR and would help diagnose pertussis more rapidly and efficiently.

Introduction of the Japanese Society for Pediatric Infectious Diseases

The Pediatric Infectious Disease Journal became an official English journal of the Japanese Society for Pediatric Infectious Diseases starting from 2022. Japanese Society for Pediatric Infectious Diseases, with a history of more than 50 years and more than 3200 members in Japan, would like to contribute to the enhancement of child health and well-being in the field of pediatric infectious diseases by collaborating academic societies and organizations worldwide through the Pediatric Infectious Disease Journal.

The clinical characteristics of pediatric coronavirus disease 2019 in 2020 in Japan

BACKGROUND

The COVID-19 pandemic has affected the lives of people of all ages. Most reports on pediatric cases suggest that children experience fewer and milder symptoms than do adults. This is the first nationwide study in Japan focusing on pediatric cases reported by pediatricians, including cases with no or mild symptoms.

METHODS

We analyzed the epidemiological and clinical characteristics and transmission patterns of 840 pediatric (<16 years old) COVID-19 cases reported between February and December 2020 in Japan, using a dedicated database which was maintained voluntarily by members of the Japan Pediatric Society.

RESULTS

Almost half of the patients (47.7%) were asymptomatic, while most of the others presented mild symptoms. At the time of admission or first outpatient clinic visit, 84.0% of the cases were afebrile (<37.5°C). In total, 609 cases (72.5%) were exposed to COVID-19-positive household members. We analyzed the influence of nationwide school closures that were introduced in March 2020 on COVID-19 transmission routes among children in Japan. Transmission within households occurred most frequently, with no significant difference between the periods before and after declaring nationwide school closures (70.9% and 74.5%, respectively).

CONCLUSIONS

COVID-19 symptoms in children are less severe than those in adults. School closure appeared to have a limited effect on transmission. Controlling household transmission from adult family members is the most important measure for prevention of COVID-19 among children.

Characteristics and etiology of infection in febrile infants aged ≤90 days

BACKGROUND

Infants ≤90 days old can exhibit non-specific signs of infection, even in cases of serious bacterial infection (SBI).

METHODS

This prospective study included infants aged ≤90 days hospitalized for fever from June 2017 to August 2019. Nasopharyngeal swabs were tested using multiplex real-time polymerase chain reaction (PCR) tests and 16S ribosomal RNA analysis of whole blood to determine causative microorganisms. Data pertaining to inflammatory markers, maximum body temperature (BT), and respiratory symptoms of infants and their cohabiting families were collected at admission.

RESULTS

A total of 110 infants were enrolled (age range, 9-90 days), 17 (15.5%) of whom presented with SBIs. White blood cell (WBC) count and absolute neutrophil count (ANC) were significantly higher in patients with SBIs than in those without, although maximum BT did not significantly differ between the SBI and non-SBI groups (n = 93). One or more viruses were detected in 82 infants (74.5%). Viruses were detected more frequently in infants with respiratory symptoms than in those without respiratory symptoms (P = 0.038), and patients with SBIs experienced significantly less respiratory symptoms than those without SBIs (P = 0.049). Moreover, viruses were more often detected in infants from cohabiting families with respiratory symptoms than in those whose family members did not exhibit respiratory symptoms (P = 0.0018).

CONCLUSION

White blood cell count, and ANC were significantly higher, and respiratory symptoms were less in infants ≤90 days old with SBIs than in those without SBIs. Microorganisms from nasopharyngeal by multiplex real-time PCR swabs could not be judged as SBI or non-SBI.

Epidemiology of urinary tract infections in children: Causative bacteria and antimicrobial therapy

BACKGROUND

Urinary tract infections (UTIs) are the most common bacterial infections in children. This study aimed to review characteristics of causative bacteria and the effectiveness of antimicrobial therapy in children with febrile UTIs.

METHODS

Clinical records of 108 patients (130 episodes) with febrile UTIs admitted to the Kawasaki Medical School Hospital between July 2009 and October 2016 were retrospectively reviewed. The characteristics of the causative bacteria, antibacterial therapy, and therapeutic effect were verified.

RESULTS

Patients were aged between 0 and 183 months (median age: 3 months). Seventy-three (67.6%) were males. Sixty-three episodes (48.5%) were diagnosed with complicated UTIs. Forty-seven episodes (36.2%) were observed in patients aged <3 months; 15 of them had complicated UTIs. Escherichia coli (E. coli) was the most common pathogen, followed by Enterococcus faecalis (E. faecalis). Blood cultures were positive in three episodes. Among the 130 episodes, 62 (47.7%) were treated with a combination of ampicillin and third-generation cephalosporins, followed by third-generation cephalosporins (31 episodes, 23.8%) and sulbactam sodium / ampicillin sodium (15 episodes, 11.5%). In case of patients with uncomplicated/complicated UTIs and patients aged <3 and ≥3 months, the most common pathogen was E. coli, followed by E. faecalis. There was no difference in therapeutic effects between "combination ampicillin and third-generation cephalosporins" and "third-generation cephalosporin monotherapy" administered for the treatment of UTIs caused by E. coli.

CONCLUSIONS

Escherichia coli is the most common pathogen among pediatric UTIs. For antibacterial therapy, third-generation cephalosporin monotherapy is effective and may not require combination therapy with ampicillin.

Understanding confidence in the human papillomavirus vaccine in Japan: a web-based survey of mothers, female adolescents, and healthcare professionals

Vaccine confidence reflects social, individual, and political factors indicating confidence in vaccines and associated health systems. In Japan, the government ceased proactive recommendation of the human papillomavirus (HPV) vaccine in June 2013, only several months after the recommendation had begun. Seven years later, as of October 2020, the suspension persists and vaccine coverage has precipitously declined, resulting in many young women being continually exposed to the risk of preventable HPV-related diseases. Accordingly, understanding stakeholder opinions on HPV vaccination issues is critical for informing strategies to improve HPV vaccine confidence and acceptance. In October 2019, we performed a nationwide, web-based survey of 1646 mothers of HPV-vaccination–eligible girls, 562 female adolescents aged 15–19 years, and 919 healthcare professionals (HCPs) in Japan. This survey captured key elements of vaccine confidence (i.e., importance, effectiveness, and safety of the HPV vaccine), awareness, and the willingness to receive (in HPV-vaccination–eligible girls) or recommend (in HCPs) the HPV vaccine, and the factors responsible for these decisions. HPV vaccine confidence was generally higher among HCPs than among mothers or female adolescents. Nearly half of all stakeholders were neutral regarding their willingness to receive/recommend the HPV vaccine. The seriousness of cervical cancer and the HPV vaccine’s effectiveness or safety were important deciding factors for receiving/recommending the HPV vaccine. Besides these factors, sufficient information and free vaccination were crucial. Our results suggest several factors that could help shape public policy and communication strategies to improve HPV vaccine confidence and acceptance in Japan.

Study of normal flora in the pharynx of healthy children

To improve our current understanding of normal flora in children, we investigated bacterial isolates from pharynx and nasopharynx of 173 and 233 healthy children, respectively. The bacterial isolation rates were compared among three age groups: infants (<1 year), toddlers (1-5 years), and school-age children (6-15 years). Gram-positive cocci (GPC) were the predominant bacteria in the pharynx (Streptococcus mitis/oralis, 87.3%; Streptococcus salivarius, 54.3%; Rothia mucilaginosa, 41.6%; Staphylococcus aureus, 39.3%). Among infants, Streptococcus salivarius and Neisseria subflava, which are related to the development of teeth, were significantly lower than in the other age groups (p<0.0001, S. salivarius; p<0.01, N. subflava). Gram-negative rods (GNR) predominated the nasopharynx (Moraxella catarrhalis, 32.1%; and Moraxella nonliquefaciens, 28.3%) except for Corynebacterium pseudodiphtheriticum (44.2%) of gram-positive rods. Among toddlers, Moraxella catarrhalis and Streptococcus pneumoniae, which are the most common pathogens in acute otitis media, were significantly higher than in the infant group (p<0.05 for both). Among bacterial species implicated in pediatric respiratory infection, Streptococcus pyogenes was isolated in 3.5% of pharyngeal samples. S. pneumoniae and Haemophilus influenzae were isolated in 22.3% and 17.2% of nasopharyngeal samples, respectively. In conclusion, normal flora of the respiratory tract differs not only by sampling site but also by age group.

Analysis of risk factors for multidrug-resistant pathogens and appropriate treatment indications for pneumonia in children with neurologic impairment

INTRODUCTION

The features of pneumonia in children with neurologic impairment (NI) resemble those of healthcare-associated pneumonia is defined as pneumonia occurring in the community associated with healthcare risk factors. There are currently no guidelines for the treatment of pneumonia in children with NI. Here, we assessed whether the guidelines applicable for treating pneumonia in adults could be applied to children with NI.

METHODS

Between 2008 and 2019, we enrolled children with NI who developed pneumonia and were treated in the pediatric ward of Kawasaki Medical School Hospital. We evaluated patient characteristics, the frequency of isolation of multidrug-resistant (MDR) pathogens, and clinical outcomes.

RESULTS

MDR pathogens were more frequently isolated from patients receiving tube feeding (TF) and/or with tracheostomy than from patients without these risk factors. Other risk factors, including a history of antibiotic therapy and methicillin-resistant Staphylococcus aureus isolation, recent hospitalization, residence in a nursing home or extended care facility, and low-dose, long-term macrolide therapy, did not significantly affect the frequency of MDR pathogen isolation. In patients receiving TF and/or with tracheostomy, treatment success was achieved in all cases treated with broad-spectrum antibiotics and 72.2% of cases treated with non-broad-spectrum antibiotics (P = 0.007). Conversely, among patients without these risk factors, no such difference was observed.

CONCLUSIONS

Our findings indicate that the guideline to select antibiotics for treating pneumonia in children with NI should be simpler and more useful than the current guidelines for adult pneumonia, based on risk factor assessment for MDR pathogens.

Nationwide surveillance of bacterial pathogens isolated from children conducted by the surveillance committee of Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2017: General overview of pathogenic antimicrobial susceptibility

A nationwide surveillance of the antimicrobial susceptibility of pediatric patients to bacterial pathogens was conducted by Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in Japan in 2017. The isolates were collected from 18 medical facilities between March 2017 and May 2018 by the three societies. Antimicrobial susceptibility testing was conducted at the central laboratory (Infection Control Research Center, Kitasato University, Tokyo) according to the methods recommended by the Clinical Laboratory Standards Institute. Susceptibility testing was evaluated in 926 strains (331 Streptococcus pneumoniae, 360 Haemophilus influenzae, 216 Moraxella catarrhalis, 5 Streptococcus agalactiae, and 14 Escherichia coli). The ratio of penicillin-resistant S. pneumoniae was 0% based on CLSI M100-ED29 criteria. However, three meropenem or tosufloxacin resistant S. pneumoniae isolates were obtained. Among H. influenzae, 13.1% of them were found to be β-lactamase-producing ampicillin resistant strains, while 20.8% were β-lactamase non-producing ampicillin-resistant strains. No capsular type b strains were detected. In M. catarrhalis, 99.5% of the isolates were β-lactamase-producing strains. All S. agalactiae and E. coli strains were isolated from sterile body sites (blood or cerebrospinal fluid). The ratio of penicillin-resistant S. agalactiae was 0%, while that of extended spectrum β-lactamase-producing E. coli was 14.3%.

Recent acute reduction in macrolide-resistant Mycoplasma pneumoniae infections among Japanese children

INTRODUCTION

Mycoplasma pneumoniae contributes to numerous pneumonia cases among children and young adults. Therefore, this study aimed to investigate the prevalence of M. pneumoniae infections among Japanese children, occurring since 2008.

METHODS

Nasopharyngeal swab specimens were obtained from all cases, following which real-time PCR was performed to identify M. pneumoniae. Further, the p1 genotypes of isolates were determined using the PCR restriction fragment length polymorphism typing method.

RESULTS

The annual rate of macrolide-resistant M. pneumoniae (MRMP) infections peaked at 81.8% in 2012 and decreased annually until 2015. Although the infection rate increased to 65.3% in 2016, it decreased again to 14.3% in 2018. Although >90% of isolates harbored the type 1 genotype until 2012, this rate decreased, and approximately 80% harbored p1 genotypes other than type 1 in 2018. Furthermore, the occurrence rate of MRMP among the type 1 isolates was very high (82.4%), whereas that among p1 genotypes other than type 1 was very low (6.5%).

CONCLUSIONS

MRMP occurrence potentially decreased owing to changes in not only antibiotic usage but also in the distribution of p1 genotype among isolates.

Multi-season analyses of causative pathogens in children hospitalized with asthma exacerbation

BACKGROUND

Respiratory viral and mycoplasma infections are associated with childhood asthma exacerbations. Here, we explored epidemiologic profile of causative pathogens and possible factors for exacerbation in a single center over a three-year period.

METHODS

Hospitalized asthmatic children with attack aged 6 months-17 years were recruited between 2012 and 2015 (n = 216). Nasopharyngeal mucosa cell samples were collected from the participants and examined by reverse transcription-polymerase chain reaction to detect rhinovirus (RV), respiratory syncytial virus (RSV), enterovirus (EV), parainfluenza virus (PIV), Mycoplasma pneumoniae, and others. Clinical features, laboratory data, asthma exacerbation intensity, and asthma severity were compared among participants. Epidemiologic profile of causative pathogens and possible factors for exacerbation were explored.

RESULTS

Viruses and/or Mycoplasma pneumoniae were detected in 75% of the participants. Rhinovirus (48%) was the most commonly detected virus in the participants with single infection, followed by RSV (6%). The median age at admission in the RV group was significantly higher than that in the RSV group. Insufficient asthma control and allergen sensitization were significantly related to RV-associated asthma exacerbation. There was no seasonality of pathogen types associated with asthma exacerbation although a sporadic prevalence of EV-D68 was observehinovirud. Rhinovirus were repeatedly detected in multiple admission cases.

CONCLUSION

Our three-year analysis revealed that patients with RV infection were significantly prone to repeated RV infection in the subsequent exacerbation and good asthma control could prevent RV-associated asthma development and exacerbation. Multiple-year monitoring allowed us to comprehend the profile of virus- and/or mycoplasma-induced asthma exacerbation.

Novel USP9X variants in two patients with X-linked intellectual disability

USP9X variants have been reported in patients with X-linked intellectual disability. Here, we report two female patients with intellectual disability and pigment abnormalities along Blaschko lines. Targeted resequencing identified two novel heterozygous variants, c.4068_4072del (p. (Leu1357Tyrfs*12)) and c.1201C>T (p. (Arg401*)), in USP9X. Our findings provide further evidence that USP9X variants cause intellectual disability.

Regulatory aspects of quality and safety for live recombinant viral vaccines against infectious diseases in Japan

Recombinant viral vaccines expressing antigens of pathogenic microbes (e.g., HIV, Ebola virus, and malaria) have been designed to overcome the insufficient immune responses induced by the conventional vaccines. Our knowledge of and clinical experience with the new recombinant viral vaccines are insufficient, and a clear regulatory pathway is needed for the further development and evaluation of recombinant viral vaccines. In 2018, the research group supported by the Ministry of Health, Labour and Welfare, Japan (MHLW) published a concept paper to address the development of recombinant viral vaccines against infectious diseases. Herein we summarize the concept paper-which explains the Japanese regulatory concerns about recombinant viral vaccines-and provide a focus of discussion about the development of recombinant viral vaccines.

A case of acute encephalophathy with residual neurological sequelae induced by immunoglobulin A vasculitis

Immunoglobulin A vasculitis (IgAV) occasionally induces central nervous system (CNS) involvement, which is usually transient with no sequelae except for hemorrhagic stroke. It is thought to be useful to measure serum and cerebrospinal fluid (CSF) cytokine levels for better understanding the pathological condition in encephalopathy, but there have been no reports in acute encephalopathy with IgAV. We describe an 8-year-old boy with IgAV who had neurological sequelae after complication of acute encephalopathy, focusing on the cytokine profiles and unique biphasic findings of magnetic resonance imaging. He presented with status epilepticus and mildly intensified area in the occipital lobe on the fluid-attenuated inversion recovery view. Arterial spin labeling (ASL) revealed the reduction of cerebral blood flow in the left hemisphere. On day 5 of illness, these abnormal findings disappeared, but delayed hyperintensity lesions on diffusion-weighted images newly emerged. Furthermore, CSF interleukin (IL)-6 levels markedly increased without elevated levels of IL-10 during the acute phase of disease. He suffered from long-lasting hemiparesis and intellectual impairment. In conclusion, acute encephalopathy with IgAV could cause neurological sequelae by prolonged seizure, and elevated IL-6 in CSF and laterality of cerebral blood flow in ASL might be useful to predict the prognosis of CNS dysfunction of IgAV.

Acute rheumatic fever associated with tenosynovitis and a unique cytokine profile

Acute rheumatic fever (ARF), caused by group A β-hemolytic streptococcus infection, is characterized by inflammation affecting several organs. There are few reports on magnetic resonance imaging (MRI) findings in patients with ARF. An 8-year-old Japanese boy presented with a prolonged fever of unknown cause and swelling of his right hand. MRI of his hand revealed tenosynovitis. Migratory arthritis and erythema marginatum appeared following the hand swelling. We diagnosed him as having ARF based on the clinical course and serological testing for group A β-hemolytic streptococcus. His serum interleukin-18 levels were lower than those typically seen in cases of systemic juvenile idiopathic arthritis (sJIA). After treatment with naproxen, his symptoms improved immediately. In conclusion, MRI findings of tenosynovitis may be useful for the diagnosis of not only sJIA but also ARF in patients presenting with a fever of unknown origin. Subsequently, the diagnosis of ARF can be confirmed with specific serological tests. Serum interleukin-18 levels may be helpful in the differential diagnosis of ARF and sJIA. Although ARF is rare in developed countries, including Japan, early diagnosis and appropriate treatment are important to prevent rheumatic heart disease.

Efficacy of primary treatment with immunoglobulin plus ciclosporin for prevention of coronary artery abnormalities in patients with Kawasaki disease predicted to be at increased risk of non-response to intravenous immunoglobulin (KAICA): a randomised controlled, open-label, blinded-endpoints, phase 3 trial

BACKGROUND

Genetic studies have indicated possible involvement of the upregulated calcium-nuclear factor of activated T cells pathway in the pathogenesis of Kawasaki disease. We aimed to assess safety and efficacy of ciclosporin, an immunosuppressant targeting this pathway, for protection of patients with Kawasaki disease against coronary artery abnormalities.

METHODS

We did a randomised, open-label, blinded endpoints trial involving 22 hospitals in Japan between May 29, 2014, and Dec 27, 2016. Eligible patients predicted to be at higher risk for intravenous immunoglobulin (IVIG) resistance were randomly assigned to IVIG plus ciclosporin (5 mg/kg per day for 5 days; study treatment) or IVIG (conventional treatment) groups, stratified by risk score, age, and sex. The primary endpoint was incidence of coronary artery abnormalities using Japanese criteria during the 12-week trial, assessed in participants who received at least one dose of study drug and who visited the study institution at least once during treatment. This trial is registered to Center for Clinical Trials, Japan Medical Association, number JMA-IIA00174.

FINDINGS

We enrolled 175 participants. One patient withdrew consent after enrolment and was excluded and one patient (in the study treatment group) was excluded from analysis because of lost echocardiography data. Incidence of coronary artery abnormalities was lower in the study treatment group than in the conventional treatment group (12 [14%] of 86 patients vs 27 [31%] of 87 patients; risk ratio 0·46; 95% CI 0·25-0·86; p=0·010). No difference was found in the incidence of adverse events between the groups (9% vs 7%; p=0·78).

INTERPRETATION

Combined primary therapy with IVIG and ciclosporin was safe and effective for favourable coronary artery outcomes in Kawasaki disease patients who were predicted to be unresponsive to IVIG.

FUNDING

Japan Agency for Medical Research and Development (grant CCT-B-2503).

LAMP-based assay can rectify the diagnosis of Yersinia pseudotuberculosis infections otherwise missed by serology

BACKGROUND

Despite being a well-known but seldom encountered zoonotic pathogen, diagnosis of Yersinia pseudotuberculosis is not necessarily easy. Infected patients occasionally present with various symptoms resembling Kawasaki disease; thus discriminating the two in the acute phase is challenging. In addition to bacterial culture and serology, novel detection methods based on loop-mediated isothermal amplification (LAMP) are reported in the literature. However, the clinical utility of LAMP-based methods in comparison with the other methods is scarcely documented in the literature.

AIM

To clarify the clinical utility of a LAMP-based method in the diagnosis of Yersinia pseudotuberculosis infection.

METHODOLOGY

Inpatients admitted due to suspected Yersinia pseudotuberculosis infection during April 2008 through March 2015 were enrolled. Results of the LAMP-based method as well as culture and serology were collected and compared.

RESULTS

Among 16 eligible cases, serology proved positive in 13 (81.3 %) cases, LAMP in eight (50 %) cases, and bacterial culture in four (25 %) cases. No significant difference among the three methods could be proved statistically. Although serology was the most sensitive method, it is known to miss cases such as young patients, whereas LAMP could complement all three cases missed by serology. Furthermore, LAMP can return the test result within a few hours from specimen receipt, whereas serology and bacterial culture requires days to weeks of time.

CONCLUSION

Although second to serology in sensitivity, the LAMP-based method proved its utility in making rapid diagnosis, and serving a complementary role to serology.

The effects of teriparatide on acceleration of bone healing following atypical femoral fracture: comparison between daily and weekly administration

We compared the effectiveness of promoting bone healing between two teriparatide preparations for atypical femoral fracture (AFF). A total of 45 AFFs were included in this study, and we compared the duration of bone union. Teriparatide administered by daily injection enhanced bone union more than weekly administration in complete AFFs.

INTRODUCTION

The efficacy of teriparatide for atypical femoral fracture (AFF) has been recently reported. Although two different teriparatide preparations can be used to treat osteoporosis in Japan, daily or weekly injection, all previous reports on the effectiveness of teriparatide for AFF only examined daily injection formulations. Therefore, we compared the promotion of bone healing between the two teriparatide preparations for AFF.

METHODS

A total of 45 consecutive AFFs in 43 Japanese patients were included in this study. They received either a daily 20-μg teriparatide injection (daily group; n = 32) or a once-a-week 56.5-μg teriparatide injection (weekly group; n = 13). We compared the clinical background and duration of bone union between these two groups.

RESULTS

When all patents were included, the fracture healing time was not significantly different between the two groups. Only patients with complete AFFs had significantly fewer daily bisphosphonate or denosumab injections than the weekly group (P < 0.05). The fracture healing time in the daily group (6.1 ± 4.1 months) was significantly shorter than that in the weekly group (10.1 ± 4.2 months) (P < 0.05). Even if the influence of bisphosphonate or denosumab usage was excluded, a similar significant difference was observed in the fracture healing time (P < 0.05). There was no significant difference between the two groups among patients with incomplete AFFs.

CONCLUSIONS

Daily teriparatide injections enhance bone union more than weekly injections in complete AFF patients.

A Safety and Immunogenicity Study of a Single Dose of a Meningococcal (Groups A, C, W, and Y) Polysaccharide Diphtheria Toxoid Conjugate Vaccine (MEN-ACWY-D) in Healthy Japanese Participants

Meningococcal disease can cause significant disability and mortality. The quadrivalent meningococcal polysaccharide diphtheria toxoid conjugate vaccine (Men-ACWY-D) protects against invasive meningococcal disease caused by serogroups A, C, W, and Y. This phase III, open-label, single-arm, multicenter study evaluated the safety and immunogenicity of a single vaccine dose in healthy Japanese adults. The study enrolled 200 participants between 2 and 55 years of age. Immunogenicity was assessed by quantifying the seroprotection rates (the proportion of participants with antibody titers ≥ 1:128 against the capsular polysaccharide from all 4 serogroups measured 28 days after vaccination). Safety endpoints included occurrence, nature, time to onset, duration, intensity, relationship to vaccination, and outcome of solicited and unsolicited adverse events (AEs) and serious AEs (SAEs). Participants included 194 adults, 2 adolescents, and 4 children. Among adults, the seroprotection rates for serogroups A, C, W, and Y were 91.2%, 80.2%, 89.1%, and 93.8%, respectively. Seroconversion rates (the proportion of participants with pre-vaccination titers of < 1:4 and a ≥ 4-fold rise from baseline) were 87.3%, 83.0%, 94.4%, and 96.4%, respectively. No immediate AEs, adverse reactions, SAEs, or deaths were reported for any age group. Men-ACWY-D is well tolerated and immunogenic, eliciting antibodies against capsular polysaccharides from all 4 serogroups in Japanese adults.

Macrolide-Resistant Mycoplasma pneumoniae Infection, Japan, 2008-2015

We evaluated isolates obtained from children with Mycoplasma pneumoniae infection throughout Japan during 2008–2015. The highest prevalence of macrolide-resistant M. pneumoniae was 81.6% in 2012, followed by 59.3% in 2014 and 43.6% in 2015. The prevalence of macrolide-resistant M. pneumoniae among children in Japan has decreased.

Cellular and humoral immunity after vaccination or natural mumps infection

BACKGROUND

This study measured cell-mediated immunity (CMI) and serum antibody to clarify the basis of breakthrough after vaccination and reinfection after mumps.

METHODS

From a pool of 54 college students, 17 seronegative subjects and 14 subjects with intermediate level of antibodies against mumps were vaccinated with a monovalent mumps vaccine, and CMI was assessed using interferon-γ release assay.

RESULTS

CMI positivity according to pre-existing antibody level, defined as titer <2.0 index units, negative; 2.0-3.9 index units, intermediate; and ≥4.0 index units, positive, was 8/17 (47.1%), 9/14 (64.3%) and 19/23 (82.6%) before vaccination, respectively. Of the 17 seronegative subjects, seven (41.2%) had a history of vaccination and/or natural infection, four (57.1%) of whom were CMI positive or intermediate. Ten (71%) of 14 subjects with intermediate antibody level had a history of vaccination or natural infection, eight (80%) of whom were CMI positive or intermediate. After vaccination the interferon (IFN)-γ and antibody titers increased significantly, but seven (41.2%) of the 17 seronegative subjects and 13 (92.9%) of the 14 intermediate-level subjects tested positive for both antibody and CMI. In a comparison of the natural infection group (confirmed as IgG seropositive and/or CMI positive without vaccination) versus the vaccination group, IgG antibody titer (mean ± SD) was 14.4 ± 8.0 versus 3.6 ± 2.4 index units (P < 0.01) and IFN-γ was 122.7 ± 90.0 pg/mL versus 59.5 ± 37.8 pg/mL (P > 0.05), respectively.

CONCLUSION

Vaccination or even natural mumps infection did not always induce both cellular and humoral immunity.

Changes in Rotavirus Genotypes before and after Vaccine Introduction: a Multicenter, Prospective Observational Study in Three Areas of Japan

In Japan, monovalent and pentavalent rotavirus (RV) vaccines were approved in 2011 and 2012, respectively. To monitor changes in the RV genotypes before and after vaccine introduction, we performed a prospective observational study among children (＜ 5 years) with gastroenteritis who tested RV-positive on antigen rapid tests. Stool samples were collected from 3 different sites in Japan: Tsu City, Mie Prefecture; Kurashiki City, Okayama Prefecture; and Isumi City, Chiba Prefecture. RV genotypes were determined using reverse transcription-polymerase chain reaction. In Tsu City, G3P[8] was dominant (61.0-77.1%) before vaccine introduction, but decreased after introduction. Meanwhile, in an inverse proportion to the decrease in G3P[8], G1P[8] increased until the 2013/14 season, when a sudden predominance of G2P[4] (100%) occurred. A similar trend was observed in Kurashiki City in terms of the extent of reduction in G3P[8] and the emergence of G2P[4]. In Isumi City, G1P[8] was dominant (70.3%) before vaccine introduction, and G9P[8] became predominant (83.3%) in the 2013/14 season. To determine whether the genotype changes are attributable to vaccines or natural epidemiological changes, ongoing continuous monitoring of the RV genotypes is required.

Chlamydia pneumoniae CPj0783 interaction with Huntingtin-protein14

Chlamydia pneumoniae is a Gram-negative, obligate intracellular pathogen that causes community-acquired respiratory infections. After C. pneumoniae invades host cells, it disturbs the vesicle transport system to escape host lysosomal or autophagosomal degradation. By using a yeast mis-sorting assay, we found 10 C. pneumoniae candidate genes involved in aberrant vesicular trafficking in host cells. One of the candidate genes, CPj0783, was recognized by antibodies from C. pneumoniae-infected patients. The expression of CPj0783 was detected at mid to late-cycle time points and increased during the inclusion maturation. Two-hybrid screening in yeast cells revealed that CPj0783 interacted with Huntingtin-interacting protein 14 (HIP14). The specific interaction between CPj0783 and HIP14 could be demonstrated by an in vivo co-immunoprecipitation assay and an in vitro GST pull-down assay. It was also demonstrated that HIP14 was localized in the Golgi apparatus and colocalized with CPj0783. HIP14 has a palmitoyl transferase activity that is involved in the palmitoylation-dependent vesicular trafficking of several acylated proteins. These findings suggest that CPj0783 might cause abnormal vesicle-mediated transport by interacting with HIP14. [Int Microbiol 18(4):225-233 (2015)].

Pediatric community-acquired pneumonia treated with a three-day course of tebipenem pivoxil

We evaluated the efficacy and safety of a 3-day treatment regimen of tebipenem pivoxil for pediatric community-acquired pneumonia. Tebipenem pivoxil was administered to 49 patients, and its effectiveness was evaluated in 36 patients 2-4 days after initiation of treatment. Thirty-two patients were cured 7-15 days after initiation of treatment. Body temperature was significantly lower on the day following initial administration (median 38.8 to 37.0 °C, n = 33). Leukocyte counts and C-reactive protein levels were significantly reduced by Day 2-4 of treatment (median 16,100 to 7800 white blood cells/μL, and 5.6 to 1.5 mg/dL, respectively; n = 28). Six of the 49 patients had mild diarrhea. Thus, we concluded that 3-day treatment with tebipenem pivoxil was safe and efficacious for treating pediatric community-acquired pneumonia.

A case of sitosterolemia due to compound heterozygous mutations in ABCG5: clinical features and treatment outcomes obtained with colestimide and ezetimibe

Sitosterolemia is a rare, autosomal recessively inherited disorder of lipid metabolism caused by mutations in the “ATP-binding cassette, subfamily G” member 5 and 8 proteins (encoded by the ABCG5 and ABCG8 genes, respectively), which play critical roles in the intestinal and biliary excretion of plant sterols. We report the clinical features and treatment outcomes of an 18-month-old Japanese girl with sitosterolemia, who presented with multiple linear and intertriginous xanthomas around the joint areas. Serum lipid analyses revealed elevated levels of total cholesterol (T-Chol: 866 mg/dL), low density lipoprotein-cholesterol (LDL-C: 679 mg/dL), and plant sterols (sitosterol: 24.6 mg/dL, campesterol: 19.2 mg/dL, stigmasterol: 1.8 mg/dL). Compound heterozygous mutations (p.R419H and p.R389H) were identified in ABCG5. The patient was placed on a low cholesterol/low plant sterol diet and treated with colestimide (a bile acid sequestrant) and ezetimibe (an NPC1L1 inhibitor). Serum T-Chol and LDL-C levels decreased to normal within 2 mo, and plant sterol levels decreased by 30% within 4 mo. The xanthomas regressed gradually, and almost completely disappeared after 1.5 yr of treatment. No further reductions of plant sterol levels were observed. Long-term follow-up is important to verify appropriate therapeutic goals to prevent premature atherosclerosis and coronary artery disease.

Numerous intertriginous xanthomas in infant: A diagnostic clue for sitosterolemia

Sitosterolemia is a very rare autosomal recessive lipoprotein metabolic disorder caused by homozygous or compound heterozygous mutations in one of the two adenosine triphosphate-binding cassette transporter genes, ABCG5 and ABCG8. Sitosterolemia is clinically characterized by xanthomas and atherosclerosis, arthritis, fever, hemolysis and macrothrombocytopenia even in early childhood. We described a 16-month-old girl, who had numerous yellowish-brown intertriginous xanthomas along the skin creases on the extremities with severe hypercholesterolemia and elevated plant sterol levels. Histopathologically, xanthoma showed aggregation of foam cells in the dermis with a zone of mucin deposits in the dermal papilla. Electron microscopy showed numerous membrane-bound lipid droplets and multivesicular lipid bodies in the foam cells, a round cell containing lipid droplets in the basal cell layer and abundant mucin deposits just beneath the basal lamina. Diagnosis of sitosterolemia was confirmed by DNA sequencing showing compound heterozygosity for previously reported missense mutations in exon 9 of ABCG5. Infants presenting with multiple xanthomas should be investigated for sitosterolemia, if there is no family history of dyslipidemia.

Rubella specific cell-mediated and humoral immunity following vaccination in college students with low antibody titers

OBJECTIVE

This study measured cell-mediated immunity (CMI) and antibodies to clarify the basis of rubella reinfection after vaccination.

METHODS

In a pool of 65 college students, 39 who exhibited hemagglutination-inhibition (HI) antibody titers against rubella of ≤ 1:16 were vaccinated with a rubella vaccine. The CMI was assessed with interferon-gamma release assay.

RESULTS

There was low correlation (r = 0.24) between the antibody titers and interferon-gamma levels at pre-vaccination status. Preexisting interferon-gamma levels were low in some subjects with low HI antibody titers of 1:8 and 1:16. Fifty-seven percent (4/7) of the subjects who were antibody-negative with past history of rubella vaccination at entry onto the study exhibited CMI. And 57% (4/7) of the subjects remained antibody-negative following a second vaccination, despite exhibiting CMI. HI antibody titers increased significantly after vaccination, whereas post-vaccination interferon-gamma levels did not exhibit significant increases. When subjects were divided (based on their past history of vaccination and antibody values) into natural infection and vaccination groups, HI antibody titers (mean ± SD) increased to 1:2(4.4 ± 1.4) from 1: 2(3.2 ± 0.4) (p = 0.065) in the natural infection group and to 1:2(4.4 ± 1.0) from 1:2(3.0 ± 0.8) (p < 0.00001) in the vaccination group following vaccination. The same classification revealed that interferon-gamma values did not increase significantly in either group following vaccination, but the interferon-gamma values at pre- and post-vaccination in the natural infection group were significantly higher than those at pre- and post-vaccination in the vaccination group (p < 0.05 and p < 0.05, respectively).

CONCLUSION

Pre-vaccination interferon-gamma levels in each HI antibody titer group were similar. And there were some subjects with antibody-positive exhibited CMI-negative. These data may explain why rubella reinfection can occur in vaccinated seropositive individuals.

Detection failure rate of chest radiography for the identification of nursing and healthcare-associated pneumonia

AIM

To clarify the detection failure rate of chest radiography for the identification of nursing and healthcare-associated pneumonia (NHCAP), we compared high-resolution computed tomography (HRCT) with chest radiography simultaneously for patients with clinical symptoms and signs leading to a suspicion of NHCAP.

METHODS

We analyzed 208 NHCAP cases and compared them based on four groups defined using NHCAP criteria, patients who were: Group A) resident in an extended care facility or nursing home; Group B) discharged from a hospital within the preceding 90 days; Group C) receiving nursing care and had poor performance status; and Group D) receiving regular endovascular treatment.

RESULTS

Chest radiography was inferior to HRCT for the identification of pneumonia (149 vs 208 cases, p < 0.0001). Among the designated NHCAP criteria, chest radiography identified pneumonia cases at a significantly lower frequency than HRCT in Group A (70 vs 97 cases, p = 0.0190) and Group C (86 vs 136 cases, p < 0.0001). The detection failure rate of chest radiography differed among NHCAP criteria; 27.8% in Group A, 26.5% in Group B, 36.7% in Group C and 5.8% in Group D. Cerebrovascular disease and poor functional status were significantly more frequent in patients in Groups A and C compared with those in Groups B and D.

CONCLUSIONS

Physicians may underestimate pneumonia shadow in chest radiographs in patients with NHCAP, and the detection failure rate of chest radiography differed among NHCAP criteria. Poor functional status may correlate with the low accuracy of chest radiography in diagnosing pneumonia.

Antibody responses of Chlamydophila pneumoniae pneumonia: Why is the diagnosis of C. pneumoniae pneumonia difficult?

The ELNAS Plate Chlamydophila pneumoniae commercial test kit for the detection of anti-C. pneumoniae-specific immunoglobulin M (IgM), IgA and IgG antibodies has become available in Japan recently. To determine the optimum serum collection point for the ELNAS plate in the diagnosis of C. pneumoniae pneumonia, we analyzed the kinetics of the antibody response in patients with laboratory-confirmed C. pneumoniae pneumonia. We enrolled five C. pneumoniae pneumonia cases and collected sera from patients for several months. The kinetics of the IgM and IgG antibody responses were similar among the five patients. Significant increases in IgM and IgG antibody titer between paired sera were observed in all patients. IgM antibodies appeared approximately 2-3 weeks after the onset of illness, reached a peak after 4-5 weeks, and were generally undetectable after 3-5 months. IgG antibodies developed slowly for the first 30 days and reached a plateau approximately 3-4 months after the onset of illness. The kinetics of IgA antibody responses were different among the five patients, and significant increases in IgA antibody titer between paired sera were observed in only two patients. Although the sample size was small, the best serum collection time seemed to be approximately 3-6 weeks after onset of illness when using a single serum sample for the detection of IgM antibodies. Paired sera samples should be obtained at least 4 weeks apart. IgA antibody analysis using ELNAS may not be a useful marker for acute C. pneumoniae pneumonia.

Diagnostic sensitivity of a rapid antigen test for the detection of Mycoplasma pneumoniae: Comparison with real-time PCR

A rapid antigen kit for the detection of the Mycoplasma pneumoniae ribosomal protein L7/L12 using an immunochromatographic assay, Ribotest Mycoplasma, became available in Japan in 2013. To determine the sensitivity of Ribotest compared with real-time polymerase chain reaction (PCR), we prospectively performed these two tests simultaneously in adolescent and adult patients with community-acquired pneumonia (CAP). In addition, we retrospectively analyzed the theoretical sensitivity of Ribotest using M. pneumoniae PCR-positive specimens from previous studies. In prospective study, 118 CAP cases were enrolled, and 16 cases were diagnosed as M. pneumoniae pneumonia; eight cases were PCR-positive, one case was culture positive, and all cases demonstrated a four-fold increase in antibody titer. Ribotest was positive in 15 cases; five cases were PCR positive and 10 cases were PCR negative. For the PCR was control test, the sensitivity, specificity, and overall agreement with Ribotest were 62.5%, 90.9%, and 88.9%, respectively. In the retrospective study, we used 1110 M. pneumoniae PCR-positive specimens, which are collected from pediatric patients with respiratory tract infection who visited 65 institutions throughout Japan. Using a cut-off level for the Ribotest of 8.3 × 10(4) copy/mL in transport medium, 667 (60.0%) specimens were theoretically positive. In conclusion, our prospective and retrospective results demonstrated that the diagnostic sensitivity of Ribotest compared with PCR was not high, at approximately 60%. Thus, treatment decisions about M. pneumoniae pneumonia should be based on clinical findings such as Japanese Respiratory Society scoring system and not on Ribotest results alone.

Setting a standard for the initiation of steroid therapy in refractory or severe Mycoplasma pneumoniae pneumonia in adolescents and adults

Serum interleukin (IL)-18 level was thought to be a useful as a predictor of refractory or severe Mycoplasma pneumoniae pneumonia, and steroid administration is reported to be effective in this situation. The serum levels of IL-18 correlated significantly with those of lactate dehydrogenase (LDH). The purpose of this study was to set a standard for the initiation of steroid therapy in M. pneumoniae pneumonia using a simple serum marker. We analyzed 41 adolescent and adult patients with refractory or severe M. pneumoniae pneumonia who received steroid therapy, and compared them with 108 patients with M. pneumoniae pneumonia who responded to treatment promptly (control group). Serum LDH levels were significantly higher in the refractory and severe group than in the control group at the initiation of steroid therapy (723 vs 210 IU/L, respectively; p < 0.0001). From receiver operating characteristic curve analysis, we calculated serum LDH cut-off levels of 364 IU/L at initiation of steroid therapy and 302 IU/L at 1-3 days before the initiation of steroid therapy. The administration of steroids to patients in the refractory and severe group resulted in the rapid improvement of symptoms and a decrease in serum LDH levels in all patients. Serum LDH level can be used as a useful parameter to determine the initiation of steroid therapy in refractory or severe M. pneumoniae pneumonia. A serum LDH level of 302-364 IU/L seems to be an appropriate criterion for the initiation of steroid therapy.

Detection of bacteria and fungi in blood of patients with febrile neutropenia by real-time PCR with universal primers and probes

Febrile neutropenia is the main treatment-related cause of mortality in cancer patients. During June 2012 to April 2014, 97 blood culture samples were collected from patients receiving chemotherapy for hematological malignancy and cancer with febrile neutropenia episodes (FNEs). The samples were examined for the presence of bacteria and fungi using real-time PCR amplification and sequencing of 16S and 18S rRNA genes. Bacteria were identified in 20 of 97 samples (20.6%) by the real-time PCR assay and in 10 of 97 (10.3%) samples by blood culture. In 6 blood culture-positive samples, the real-time PCR assay detected the same type of bacteria. No fungi were detected by the real-time PCR assay or blood culture. During antibiotic therapy, all samples were negative by blood culture, but the real-time PCR assay yielded a positive result in 2 cases of 2 (100%). The bacterial DNA copy number was not well correlated with the serum C-reactive protein titer of patients with FNEs. We conclude that a real-time PCR assay could provide better detection of causative microbes' in a shorter time, and with a smaller blood sample than blood culture. Using a real-time PCR assay in combination with blood culture could improve microbiological documentation of FNEs.

[Effect of new oral antimicrobial agents in outpatient treatment of pneumonia in children]

In November 2004, "Guidelines for the Management of Respiratory Infectious Diseases in Children in Japan" was published ahead of the rest of the world, by Japanese Society of Pediatric Pulmonology/Japanese Society for Pediatric Infectious Diseases, based on the data on causative organisms in the lower respiratory tract. In its 2011 version, classification of the severity of pneumonia was renewed based on the latest information. As a result, many types of pneumonia in children are now classified as mild or moderate. This means that many patients who might have conventionally required hospital treatment can now be managed on an outpatient basis. The reason for realization of the wider range of outpatient treatment is the availability of two new oral antimicrobial agents, tebipenem pivoxil and tosufloxacin tosilate hydrate, for the treatment of infections in children. Analysis of data on medical expenses shows a decreased rate of hospitalization due to pneumonia year by year after launch of these two drugs, suggesting that these drugs have contributed to wider range of outpatient treatment. This manuscript discusses the effect of tebipenem pivoxil and tosufloxacin tosilate hydrate in the treatment of pneumonia.

[Long effect of a booster on rubella antibodies from each original HI titer following vaccination]

This study was performed to clarify which titers of a pre-existing antibody could be efficiently boosted by vaccination and to assess the persistence of the antibodies. Two hundred healthy volunteer students with HI antibody titers of < or = 1:32 were enrolled. There were 6-16% of subjects with the negative HI antibody who had B-cell memory against rubella, because the EIA-IgM antibody remained negative and/or the avidity of the EIA-IgG antibody was high after vaccination. Furthermore most of them had already been vaccinated just once before. The ratio of those in whom the antibody levels increased significantly at one month after vaccination were 98%, 87%, 67% and 32% in subjects with an HI antibody titer of <1:8, < or =1: 8, < or =1:16 and < or =1:32 at pre-vaccination, respectively. The titers decreased significantly at two years after vaccination, however the ratio of decrease under each original level being 4%, 21.9%, 42.6% and 73.5% in each group of <1:8, < or =1: 8, < or =1:16 and < or = 1: 32, respectively. In comparison with the numbers of the subjects with <1: 8, the ones with < or = 1: 8, < or = 1:16 and < or = 1:32 increased 1.5-, 2.5- and 4.7-fold, respectively. Therefore, the recommendation of an HI antibody titer < or = 1:16 for vaccination in Japan is thought to be loose, although this is to decrease the risk of congenital rubella syndrome. We think that a new assay for cellular immunity for rubella should be developed in the future in order to ascertain whether congenital rubella syndrome will be prevented or not.