Invasive pneumococcal disease caused by non-vaccine Streptococcus pneumoniae serotype 24B in an immunocompetent child

Invasive pneumococcal disease typically occurs in immunocompromised patients, although some vaccine strains of Streptococcus pneumoniae have been reported to cause invasive pneumococcal disease in immunocompetent vaccine recipients. In this study, we presented a case of a 16-month-old immunocompetent patient with lung abscess and empyema caused by nonvaccine S. pneumoniae serotype 24B. A consolidation occupying the right upper lobe in the chest computed tomography results, as observed at presentation, changed to thick-walled cavitary lesions at the end of a month of intravenous antibiotics, and antibiotics were continued for a total of two months. To the best of our knowledge this is the first report that focuses on the risk of invasive pneumococcal disease caused by S. pneumoniae serotype 24B in an immunocompetent child.

Catheter-associated urinary tract infection and urinary tract abnormalities in young children: A retrospective study

INTRODUCTION

Studies investigating the role of urinary tract abnormalities in the development of catheter-associated urinary tract infections (CAUTI) in young children are limited. Thus, in the present study, we aimed to determine whether there is an association between CAUTI and urinary tract abnormalities.

METHODS

We performed abdominal imaging studies on all patients aged <6 years with CAUTI admitted to the pediatric intensive care units (PICU) and high care unit (HCU) at Keio university or Fukuoka Children's Hospital from April 1, 2018 to July 31, 2022. Among 40 children who developed CAUTI, 13 (33 %) had abnormal urogenital images. Further, two case-control studies were conducted before and after propensity score matching, and the groups were compared using multivariable logistic regression models to analyze the effects of various factors on CAUTI development.

RESULTS

In the multivariate logistic regression models, abnormal urogenital images (OR 5.30 [95 % CI, 2.40-11.7] and OR 3.44 [95 % CI, 1.16-9.93]) and duration of catheterization >10 days (OR 2.76 [95 % CI, 1.28-5.96] and OR 3.44 [95 % CI, 1.16-9.93]) were found to be significantly associated with development of CAUTI, both before (39 cases, 459 controls) and after propensity score matching (36 cases, 72 controls). Further, CAUTI in young children in the PICU or HCU was significantly associated with imaging abnormalities of the urinary tract.

CONCLUSIONS

These results suggest that not only the presence of catheters, but also urinary tract malformations may contribute to the development of CAUTI in young children.

Cost-effectiveness analysis of 20-valent pneumococcal conjugate vaccine for routine pediatric vaccination programs in Japan

BACKGROUND

The Japanese National Immunization Program currently includes the pediatric 13 valent pneumococcal conjugate vaccine (PCV13) to prevent pneumococcal infections. We aimed to evaluate the cost-effectiveness of 20-valent PCV (PCV20) as a pediatric vaccine versus PCV13.

METHODS

A decision-analytic Markov model was used to estimate expected costs, quality-adjusted life-years (QALYs), and prevented cases and deaths caused by invasive pneumococcal disease, pneumonia, and acute otitis media over a ten-year time horizon from the societal and healthcare payer perspectives.

RESULTS

PCV20 was dominant, i.e. less costly and more effective, over PCV13 (gained 294,599 QALYs and reduced Japanese yen [JPY] 352.6 billion [2.6 billion United States dollars, USD] from the societal perspective and JPY 178.9 billion [USD 1.4 billion] from the payer perspective). Sensitivity and scenario analyses validated the robustness of the base scenario results. When comparing PCV20 with PCV13, the threshold analysis revealed an incremental cost-effectiveness ratio that was within the threshold value (JPY 5 million/QALY) at a maximum acquisition cost of JPY 74,033 [USD 563] (societal perspective) and JPY 67,758 [USD 515] (payer perspective).

CONCLUSIONS

As a pediatric vaccine, PCV20 was dominant over PCV13 regardless of the study perspective.

Pneumocystis jirovecii pneumonia after CD4+ T-cell recovery subsequent to CD19-targeted chimeric antigen receptor T-cell therapy: A case report and brief review of literature

BACKGROUND

CD19-targeted chimeric antigen receptor (CAR)-T cell therapy involves administration of patient-derived T cells that target B cells, resulting in B-cell depletion and aplasia. In immunity against Pneumocystis jirovecii (Pj), CD4+ T cells and, more recently, B cells, are generally considered important. Antigen presentation by B cells to CD4+ T cells is particularly important. Trimethoprim-sulfamethoxazole (TMP/SMX) for Pj pneumonia (PJP) prophylaxis is generally discontinued when the CD4+ T-cell count is >200/μL. Here we report the first case, to our knowledge, of PJP in a patient with a CD4+ T cell count of >200/μL after CAR-T cell therapy.

CASE

A 14-year-old girl developed hemophagocytic lymphohistiocytosis (HLH) after cord blood transplantation (CBT) for relapsed precursor B-cell acute lymphoblastic leukemia (B-ALL). Twenty-one months after CBT, she was diagnosed with combined second relapse in the bone marrow and central nervous system. The patient was treated with CD19-targeted CAR-T cell therapy for the relapse. After CAR-T cell therapy, the patient remained in remission and continued to receive TMP/SMX for PJP prophylaxis. Seven months after CAR-T cell therapy, CD4+ T cells recovered and TMP/SMX was discontinued. The B-cell aplasia persisted. Ten months after CAR-T cell therapy, the patient developed PJP. The patient was also considered to have macrophage hyperactivation at the onset of PJP. Treatment with immunoglobulin, TMP/SMX, and prednisolone was initiated, and the patient's symptoms rapidly ameliorated.

CONCLUSION

The patient in the present case developed PJP despite a CD4+ T-cell count of >200/μL after CAR-T cell therapy, probably because of inadequate CD4+ T-cell activation caused by B-cell depletion after CAR-T cell therapy and repeated abnormal macrophage immune responses after CBT. It is important to determine the duration of TMP/SMX for prophylaxis after CAR-T cell therapy according to each case, as well as the CD4+ T-cell count.

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.

Distinct association between chronic Epstein-Barr virus infection and T cell compartments from pediatric heart, kidney, and liver transplant recipients

Chronic Epstein-Barr virus (EBV) infection after pediatric organ transplantation (Tx) accounts for significant morbidity and mortality. The risk of complications, such as posttransplant lymphoproliferative disorders, in high viral load (HVL) carriers is the highest in heart Tx recipients. However, the immunologic signatures of such a risk have been insufficiently defined. Here, we assessed the phenotypic, functional, and transcriptomic profiles of peripheral blood CD8+/CD4+ T cells, including EBV-specific T cells, in 77 pediatric heart, kidney, and liver Tx recipients and established the relationship between memory differentiation and progression toward exhaustion. Unlike kidney and liver HVL carriers, heart HVL carriers displayed distinct CD8+ T cells with (1) up-regulation of interleukin-21R, (2) decreased naive phenotype and altered memory differentiation, (3) accumulation of terminally exhausted (TEX PD-1+T-bet-Eomes+) and decrease of functional precursors of exhausted (TPEX PD-1intT-bet+) effector subsets, and (4) transcriptomic signatures supporting the phenotypic changes. In addition, CD4+ T cells from heart HVL carriers displayed similar changes in naive and memory subsets, elevated Th1 follicular helper cells, and plasma interleukin-21, suggesting an alternative inflammatory mechanism that governs T cell responses in heart Tx recipients. These results may explain the different incidences of EBV complications and may help improve the risk stratification and clinical management of different types of Tx recipients.

Effectiveness of inactivated influenza and COVID-19 vaccines in hospitalized children in 2022/23 season in Japan - The first season of co-circulation of influenza and COVID-19

We have analyzed the inactivated vaccine effectiveness (VE)for preventing influenza hospitalization by test-negative design in the 2022/23 season. This is the first season of co-circulation of influenza and COVID-19, and a unique period because all inpatients received COVID-19 screening. Among 536 children hospitalized with fever, none were positive for both influenza and SARS-CoV-2. The adjusted VE for preventing influenza A for all children, the 6-12-year-old group, and those with underlying diseases was 34 % (95 ％CI, -16 %-61 %, n = 474), 76 % (95 ％ CI, 21 %-92 %, n = 81), and 92 % (95 ％ CI, 30 %-99 %, n = 86), respectively. Only 1 out of 35 hospitalized cases with COVID-19, and 42 out of 429 controls, had been immunized with COVID-19 vaccine. This is the first report showing influenza VE by age group in children in this limited season. We still recommend the inactivated influenza vaccine for children based on the significant VE in subgroup analysis.

Be aware of Extended-spectrum β-lactamase-producing Escherichia coli in neonates and Listeria monocytogenes in young children with bacterial meningitis in Japan

Nationwide surveillance of pediatric bacterial meningitis in Japan from 2019 to 2021 revealed two uncommon situations not covered by the recommended empiric treatment that were not rare in Japan, namely, extended-spectrum β-lactamase-producing-producing Escherichia coli in neonates and Listeria monocytogenes in children older than 1 month.

Trends in effectiveness of inactivated influenza vaccine in children by age groups in seven seasons immediately before the COVID-19 era

Background

Methods

Results

Conclusions

High success rate of nocturnal enuresis treatment during the stay-home period for COVID-19

OBJECTIVES

To clarify whether enuresis treatment was more effective during the stay-home period for the coronavirus disease 2019 pandemic, when restrictions on activities enabled patients to concentrate on treatment.

METHODS

We performed a retrospective, nonrandomized cohort study for monosymptomatic enuresis during the coronavirus disease 2019 pandemic (March-June 2020) and a 2-year comparator period (March-June 2018 and March-June 2019). Primary outcome was treatment response, defined as a change in the number of wet nights per week within 6 months following enrollment. The time-dependent occurrence of treatment response was evaluated with the Kaplan-Meier method and the log-rank test. The Cox proportional hazards regression model was used to identify risk factors for treatment response. The range of appropriate sample sizes for this primary outcome was 39-48.

RESULTS

Of our 41 enrolled patients, 28 (68%) were male and mean age was 8.8 years. The complete response rate was 73% during the coronavirus disease 2019 pandemic period and 27% during the comparator period. Log-rank tests showed a higher cumulative incidence of complete response in the pandemic period (P = 0.020). Cox regression analysis identified treatment during the coronavirus disease 2019 pandemic (hazard ratio 2.533; 95% confidence interval 1.069-6.006) and dinner before 19:00 (hazard ratio 4.184; 95% confidence interval 1.56-11.252) as significantly associated with treatment response.

CONCLUSIONS

The rate of enuresis treatment response was uncommonly high during the stay-home period for the coronavirus disease 2019 pandemic. Restrictions on daily life may provide opportunities to concentrate on treatments for chronic illnesses, leading to more success.

Digestive Decolonization of Colorectal Carriage of Vancomycin-resistant Enterococcus faecium in a Japanese Adult

Patients with vancomycin-resistant Enterococcus (VRE) colonization should be managed in an isolation room with contact precautions. We herein report a patient whose colorectal carriage of VRE was successfully decolonized using concomitant bowel irrigation with polyethylene glycol, probiotics, and oral antimicrobials, linezolid and orally-administered daptomycin, for release from isolation and contact precautions. We therefore would like to suggest a potential strategy for managing patients with VRE colonization.

The first case report of pediatric acute appendicitis caused by "Candidatus Actinobaculum timonae"

A 14-year-old boy presented to the hospital with pain in the right lower abdomen. His condition was diagnosed as acute appendicitis. An emergency operation was performed, and histopathological examination revealed an actinomycete-related organism in the excised appendicitis specimen. On 16S rRNA gene sequence analysis, "Candidatus Actinobaculum timonae" was identified, which is the first known case in a pediatric patient.

Lack of persisting antibody in a post-transplant patient after vaccine-strain varicella

BACKGROUND

LAVV have historically been avoided in children after solid organ transplantation. However, it has been reported that post-transplant, children without severe immunosuppression can generate anti-varicella antibody after immunization but the duration of the response is not clear. Furthermore, the origin of the varicella virus in immunosuppressed patients who develop varicella after vaccination is often unclear.

CLINICAL PROGRESS

A female child received LAVV 30 months after a living donor liver transplant at the age of 2 months. Varicella rash appeared on the trunk 16 days after vaccination and gradually spread over the body. The patient was treated with intravenous acyclovir followed by oral therapy and recovered fully. The virus detected in blisters was derived from the vaccine-type strain. Paired sera before and after the onset of varicella showed an increase in antibody titer. However, 2 years after onset, the antibody titer decreased to undetectable again.

CONCLUSIONS

This was an informative case of varicella due to vaccine strain attenuated virus. Antibody levels were not maintained over many years. Although varicella was caused by the vaccine-type strain, repeated vaccinations may be necessary for post-transplant patients who develop varicella.

Risk factors in pediatric hospitalization for influenza A and B during the seven seasons immediately before the COVID-19 era in Japan

INTRODUCTION

The risk factors in pediatric influenza immediately before the COVID-19 era are not well understood. This study aims to evaluate the risk factors for hospitalization in pediatric influenza A and B for the recent seasons.

METHODS

Children with a fever of ≥38 °C and laboratory-confirmed influenza at 20 hospitals in outpatient settings in Japan in the 2013/14 to 2019/20 seasons were retrospectively reviewed. Possible risk factors, including gender, age, comorbidities, nursery school or kindergarten attendance, earlier diagnosis, no immunization, lower regional temperature, earlier season, and period of onset, were evaluated using binary logistic regression methods.

RESULTS

A total of 13,040 (type A, 8861; B, 4179) children were evaluated. Significant risk factors (p < 0.05) in multivariate analyses were young age, lower regional temperature, earlier season, respiratory illness (adjusted odds ratio [aOR]:2.76, 95% confidence interval [CI]:1.84-4.13), abnormal behavior and/or unusual speech (aOR:2.78, 95% CI:1.61-4.80), and seizures at onset (aOR:16.8, 95% CI:12.1-23.3) for influenza A; and young age, lower regional temperature, respiratory illness (aOR:1.99, 95% CI:1.00-3.95), history of febrile seizures (aOR:1.73, 95% CI:1.01-2.99), and seizures at onset (aOR:9.74, 95% CI:5.44-17.4) for influenza B.

CONCLUSIONS

In addition to previously known factors, including young age, seizures, and respiratory illness, abnormal behavior and/or unusual speech and lower regional temperature are new factors. Negative immunization status was not a risk factor for hospitalization. A better understanding of risk factors may help improve the determination of indications for hospitalization during the future co-circulation of influenza and COVID-19.

Influenza vaccine effectiveness against influenza A in children based on the results of various rapid influenza tests in the 2018/19 season

During influenza epidemics, Japanese clinicians routinely conduct rapid influenza diagnostic tests (RIDTs) in patients with influenza-like illness, and patients with positive test results are treated with anti-influenza drugs within 48 h after the onset of illness. We assessed the vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) in children (6 months-15 years old, N = 4243), using a test-negative case-control design based on the results of RIDTs in the 2018/19 season. The VE against influenza A(H1N1)pdm and A(H3N2) was analyzed separately using an RIDT kit specifically for detecting A(H1N1)pdm09. The adjusted VE against combined influenza A (H1N1pdm and H3N2) and against A(H1N1)pdm09 was 39% (95% confidence interval [CI], 30%-46%) and 74% (95% CI, 39%-89%), respectively. By contrast, the VE against non-A(H1N1)pdm09 influenza A (presumed to be H3N2) was very low at 7%. The adjusted VE for preventing hospitalization was 56% (95% CI, 16%-77%) against influenza A. The VE against A(H1N1)pdm09 was consistently high in our studies. By contrast, the VE against A(H3N2) was low not only in adults but also in children in the 2018/19 season.

Comparison of 0.5% chlorhexidine gluconate alcohol with 10% povidone-iodine for skin disinfection in children to prevent blood culture contamination

INTRODUCTION

Various disinfectants, such as povidone iodine (PVI)¹, alcohol preparations, and chlorhexidine gluconate ethanol (CHG-ALC), are used for disinfection prior to blood sampling for culture.

METHODS

This retrospective cohort study compared the usefulness and effectiveness of CHG-ALC and PVI in pediatric venipuncture. We applied 0.5% w/v CHG-ALC or 10% PVI as an antiseptic for phlebotomies on pediatric outpatients and inpatients with suspected bacterial infection between November 2017 and April 2019. We conducted logistic regression analysis to define the differences associated with the choice of disinfectant, collection site, and the staff member collecting the blood sample (explanatory variables) and the presence of contamination (objective variable). Based on these results, we performed propensity score matching.

RESULTS

The total number of specimens was 1460. The propensity score matching indicated that CHG-ALC reduced the incidence of blood culture contamination more effectively than PVI (0.4%, 2/479 cultures versus 2.5%, 12/479 cultures; relative risk, 0.163 [95% confidence interval, 0.036 to 0.733]; P = 0.012). There were no differences in the contamination rates between cultures of blood drawn from a vascular catheter and those of blood obtained percutaneously. Higher contamination rates were found when junior residents performed the venipuncture.

CONCLUSIONS

Compared with PVI, CHG-ALC dries rapidly with no pigmentation and has a long-lasting antiseptic effect. Overall, CHG-ALC skin preparations were more efficacious than the PVI preparations for blood sampling in children.

Pertussis Epidemic in Lower-Grade Schoolchildren Without Preschool Vaccination Boosters

We investigated the characteristics of patients with pertussis who did not receive preschool vaccination boosters. Fifteen patients with laboratory-confirmed pertussis and 29 pertussis-negative patients were compared. All pertussis-positive patients, but only 17% of pertussis-negative patients, were elementary school age and older. There is a need to study the utility of routine preschool pertussis vaccine booster in Japan.

Herbal Medicine-Induced Seizures in Children: Single-Center Experience Over 18 Months

Many common household herbal preparations may have seizurogenic ingredients. We report 15 children with seizures following exposure to such compounds: oral ingestion of liquid preparation in 13, and local application of balm and Eucalyptus oil ingestion in one each. All children, except one, had generalized seizures. This study highlights the need to address this history during evaluation of first seizure, and increase awareness of seizurogenic potential of such preparations.

Recent trends in pediatric bacterial meningitis in Japan, 2016-2018 - S. agalactiae has been the most common pathogen

BACKGROUND

Haemophilus influenzae type b (Hib) vaccine and pneumococcal conjugated vaccine (PCV) have been widely used since 2010 in Japan. The overall incidence of bacterial meningitis decreased thereafter. Streptococcus agalactiae has become the main organism.

OBJECTIVES

The purpose of the present study was to investigate the incidence rate per 1000 admissions of bacterial meningitis and the change in causative organisms in subsequent years.

METHODS

A cross-sectional, multicenter, non-interventional retrospective study regarding pediatric bacterial meningitis was conducted in Japan in 2019. We analyzed the epidemiological and clinical data for 2016-2018, and compared the information obtained in our previous nationwide survey database. We also investigated the risk factors for disease outcome.

RESULTS

In the 2016-2018 surveys, 197 patients from 153 hospitals from all prefectures were evaluated. S. agalactiae (0-3 months, 39%), Streptococcus pneumoniae (2-112 months, 20%), and E. coli (0-136 months, 13%) were the main organisms. The total number of patients hospitalized with bacterial meningitis per 1000 admissions decreased from 1.00 to 1.68 in 2000-2010 to 0.38 in 2013-2015, bu remained stable thereafter (0.35-0.40 in 2016-2018). Only one case with Neisseria meningitidis was reported. Nine cases with death were reported, including four cases with S. agalactiae. Risk factors for death and sequelae were consciousness disturbance, duration of convulsion, low CSF glucose levels, and disuse of dexamethasone (p < 0.05).

CONCLUSIONS

The incidence in pediatric bacterial meningitis remained low, and S. agalactiae remains the most common cause of bacterial meningitis in Japan since 2012. S. pneumoniae is the most common cause after 3 months of age.

Effectiveness of inactivated influenza vaccine in children by vaccine dose, 2013-18

OBJECTIVES

We assessed the vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) by vaccine dose in children aged 6 months to 12 years for whom two doses are recommended in Japan to ascertain the appropriate vaccine doses.

METHODS

VE was assessed according to a test-negative case-control design based on rapid influenza diagnostic test (RIDT) results. Children aged 6 months to 12 years with a fever ≥38 °C who had received an RIDT in outpatient clinics of 24 hospitals were enrolled for all five seasons since 2013/14. VE by vaccine dose (none vs. once or twice, and once vs. twice) was analyzed.

RESULTS

In the dose analysis, 20,033 children were enrolled. Both one- and two-dose regimens significantly reduced cases in preventing any influenza, influenza A, and influenza B, but there was no significant difference in adjusted VE between one- and two-dose regimens overall (adjusted OR, 0.560 [95% CI, 0.505-0.621], 0.550 [95% CI, 0.516-0.586]), 0.549 [95% CI, 0.517-0.583], and 1.014 [95% CI, 0.907-1.135], for none vs. once, none vs. twice, none vs. once or twice, and once vs. twice for any influenza, respectively). Both one- and two-dose regimens significantly reduced cases with any influenza and influenza A every season. Also, both regimens significantly reduced cases of any influenza, influenza A, and influenza B among children aged 1-12 years, especially among those aged 1-5 years. In the 2013/14, 2015/16, and 2016/17 seasons, however, only the two-dose regimen was significantly effective in preventing influenza B. Both one- and two-dose regimens significantly reduced cases involving hospitalization due to any influenza and influenza A.

CONCLUSIONS

Both one- and two-doses regimens of IIV were effective in preventing influenza for children aged 6 months to 12 years. The two-dose regimen was more effective against influenza B in some seasons.

Nosocomial infection by human bocavirus and human rhinovirus among paediatric patients with respiratory risks

BACKGROUND

Nosocomial infections by respiratory viruses undetected by rapid tests are not often diagnosed. For paediatric patients with background diseases, nosocomial infection could be fatal.

AIM

To determine the relationship between developing symptoms by respiratory viruses undetectable by rapid tests and respiratory risks and to improve the management of infection control.

METHODS

Two episodes of nosocomial infection by human bocavirus (HBoV) and human rhinovirus (HRV) were retrospectively investigated in a tertiary hospital paediatric ward in Japan. Viruses were identified by polymerase chain reaction to determine infection control management. When viruses of the same species were detected from different patients, the virus homology was investigated. The relationship between respiratory risks and developing symptoms was statistically investigated.

FINDINGS

Three and four patients with respiratory risks in the HBoV and HRV outbreaks, respectively, developed respiratory symptoms. The nucleotide sequences of two patients in the HBoV outbreak and all four patients in the HRV outbreak were phylogenetically close. In both outbreaks, the patients with respiratory risks developed significantly more symptoms than those without any risk (P = 0.035 and 0.018, respectively). After the patients with respiratory infection were separated from those with respiratory risks, no additional nosocomial infection occurred.

CONCLUSION

Patients with respiratory risks easily develop respiratory symptoms and acquire severe symptoms of nosocomial infection by those viruses. In a paediatric ward, we should adopt not only standard precautions but also isolation management of the patients with respiratory symptoms, even if they have negative results in rapid tests.

Round pneumonia due to Chlamydia pneumoniae in a child

Round pneumonia is a disease commonly recognized in the pediatric age group, especially under the age of 8 years. Streptococcus pneumoniae is the most common agent causing this characteristic type of pneumonia. We herein report a case of a 6-year-old boy with only mild cough and low-grade fever who was then diagnosed with round pneumonia due to Chlamydia pneumoniae. He had multiple round opacities in the right lower lung field, and the symptoms subsided soon after oral administration of antibiotics.

Effectiveness of inactivated quadrivalent influenza vaccine in the 2015/2016 season as assessed in both a test-negative case-control study design and a traditional case-control study design

Both traditional case-control studies (TCCSs) and test-negative case-control studies (TNCCSs) are commonly used to assess influenza vaccine effectiveness (VE). To compensate for the fact that observational studies are susceptible to bias, we combined both methods to assess VE in one geographical area during the 2015/2016 season, when influenza A (H1N1)pdm was dominant. Our TNCCS covered 331 children aged 6 months to 15 years who visited our hospital with fever, including 182 with influenza, and our TCCS covered 812 pediatric outpatients aged 6 months to 15 years, including 214 with influenza. Influenza infection and vaccination history were reviewed, and VE was calculated as (1 - odds ratio) × 100. In the TNCCS, VE against influenza A was 68% (95% CI 47-81) overall, and 70% (48-83) for those given two doses; against influenza B, VE was 37% (- 12-64) overall and 49% (2-74) for two doses. In the TCCS, VE against influenza A was 44% (15-63) overall and 44% (13-64) for two doses, and VE against influenza B was 24% (- 19-52) overall and 41% (3-64) for two doses.

CONCLUSION

Both studies confirmed significant VE against influenza A, significant two-dose VE against influenza B, and better two-dose VE than one-dose VE. What is Known: • Influenza vaccine effectiveness (VE) varies from year to year. • Observational studies are conventionally used for VE assessment. However, they are inherently susceptible to bias and confounding. What is New: • This is the first report of influenza VE assessment using more than one observational study and performed in a specific area during the same season. • VE estimates obtained in our traditional case-control study were lower than those in our test-negative case-control study, but both studies found significant VE against influenza.

Purulent lymphadenitis caused by Staphylococcus argenteus, representing the first Japanese case of Staphylococcus argenteus (multilocus sequence type 2250) infection in a 12-year-old boy

Staphylococcus argenteus is a novel species separated from a strain of coagulase-positive, non-pigmented S. aureus. Although S. argenteus has been reported to occur globally, multilocus sequence type (ST) 2250 is mainly found in Northeastern Thailand. Because conventional biochemical testing misidentifies this pathogen as S. aureus, multilocus sequence typing (MLST) or nucA sequencing is recommended to distinguish between S. argenteus and S. auereus. The patient was a previously healthy 12-year-old boy who was admitted because of right inguinal lymphadenitis and cellulitis. Although intravenous cefazolin was administered, his lymphadenitis worsened and formed an abscess on day 6 of hospitalization. Incision and drainage were performed on day 7 of hospitalization. Cefazolin was changed to oral cefaclor, and the patient was successfully treated over a period of 5 weeks. No recurrence was observed throughout 12-months of follow-up. He had a history of right axillary lymph node abscess 2 months before this admission, which was successfully treated with incision, drainage, and antibiotic therapy. He has lived in Japan since birth and never traveled abroad. He had no opportunity to interact with foreigners. His immune function, especially neutrophil function, was tested and we did not find any dysfunction. First, methicillin-sensitive S. aureus was misidentified from the abscess culture. Subsequently, the causative agent was re-identified as S. argenteus ST2250 based on MLST. To our knowledge, this is the first case of S. argenteus ST2250 infection in Japan. This pathogen should be taken into consideration in the diagnosis if the patient has atypical non-pigmented S. aureus.

Successful discontinuation of immunoglobulin G replacement at age 10 in a patient with immunoglobulin G2 deficiency

CONTEXT

Immunoglobulin G2 deficiency that persists beyond the age of 6 years is likely to be permanent.

CASE REPORT

We report on a young Japanese female, diagnosed as having immunoglobulin G2 deficiency and low anti-pneumococcal immunoglobulin G2 antibody levels when 3 years old, with a subsequent medical history of frequent respiratory infections and asthma. Monthly intravenous immunoglobulin replacement therapy was started at 4 years of age. After 8 years of age, an anti-pneumococcal immunoglobulin G2 trough level could be maintained with administration intervals longer than 6 weeks, and after 9 years and 10 months of age, therapy was discontinued. The frequency of hospital admissions was reduced by the introduction of the replacement therapy (from 8.4 times/year before the introduction to 1.1 times/year during the therapy). The patient was also able to discontinue daily medications for asthma, and serum immunoglobulin G2 was maintained at a normal level even after the cessation of replacement therapy.

CONCLUSION

Termination of immunoglobulin replacement therapy in a patient with a symptomatic immunoglobulin G2 deficiency is possible, even for a child older than 6 years.

Trivalent inactivated influenza vaccine effective against influenza A(H3N2) variant viruses in children during the 2014/15 season, Japan

The 2014/15 influenza season in Japan was characterised by predominant influenza A(H3N2) activity; 99% of influenza A viruses detected were A(H3N2). Subclade 3C.2a viruses were the major epidemic A(H3N2) viruses, and were genetically distinct from A/New York/39/2012(H3N2) of 2014/15 vaccine strain in Japan, which was classified as clade 3C.1. We assessed vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) in children aged 6 months to 15 years by test-negative case–control design based on influenza rapid diagnostic test. Between November 2014 and March 2015, a total of 3,752 children were enrolled: 1,633 tested positive for influenza A and 42 for influenza B, and 2,077 tested negative. Adjusted VE was 38% (95% confidence intervals (CI): 28 to 46) against influenza virus infection overall, 37% (95% CI: 27 to 45) against influenza A, and 47% (95% CI: -2 to 73) against influenza B. However, IIV was not statistically significantly effective against influenza A in infants aged 6 to 11 months or adolescents aged 13 to 15 years. VE in preventing hospitalisation for influenza A infection was 55% (95% CI: 42 to 64). Trivalent IIV that included A/New York/39/2012(H3N2) was effective against drifted influenza A(H3N2) virus, although vaccine mismatch resulted in low VE.

The first case of recurrent ultra late onset group B streptococcal sepsis in a 3-year-old child

Group B streptococcus (GBS) is a commonly recognized cause of sepsis and meningitis in neonatal and young infants. Invasive GBS infection is classified into early onset GBS disease (EOD, day 0-6), late onset GBS disease (LOD, day 7-89) and ultra late onset GBS disease (ULOD, after 3 months of age). ULOD is uncommon and recurrence is especially rare. We present the first recurrent case of ULOD GBS sepsis in 3-year-old girl with a past medical history of hydrops fetalis and thoracic congenital lymphatic dysplasia. The first episode presented as sepsis at 2 years 8 months of age. The second episode occurred as sepsis with encephalopathy at 3 years 1 months of age. During each episode, the patient was treated using intravenous antimicrobials and her condition improved. Serotype examination was not performed in the first episode, but GBS type V was serotyped in the second episode. ULOD over 1 year of age is quite rare and may recur.

Utility of fractional excretion of urea in the differential diagnosis of acute kidney injury in children

INTRODUCTION

The fractional excretion of sodium (FENa) has been used as an index for the differential diagnosis of acute tubular necrosis (ATN) and prerenal acute kidney injury (AKI). The reliability of this index, however, decreases with the use of the diuretic agent furosemide. The fractional excretion of urea nitrogen (FEUN) has been shown to be useful in such settings in adults. The objective of this study was to examine whether FEUN is also useful in these settings in children.

METHODS

We assessed 102 episodes of AKI in 74 children, classifying these into three groups based on history, physical examination, urine examination and subsequent clinical course: (1) prerenal AKI without furosemide (N = 37), (2) prerenal AKI with furosemide (N = 32) and (3) ATN (N = 33).

RESULTS

Of the 37 prerenal AKI episodes without furosemide, 35 showed low FENa of <1 %, with an overall average of 0.35 ± 0.11 %, whereas prerenal AKI with furosemide (1.63 ± 0.37 %) and ATN (8.76 ± 2.11 %) were associated with a higher FENa. FEUN in the clinical setting of prerenal AKI was lower than that in ATN (27.9 ± 2.1 vs. 51.6 ± 3.8 %, respectively) and, in contrast to FENa, not significantly different between the categories of prerenal AKI with and without furosemide (29.2 ± 3.1 vs. 25.1 ± 2.9, respectively). The sensitivity of FEUN <35 % was 75 % in prerenal AKI with furosemide, whereas that of FENa was 53 %.

CONCLUSIONS

FEUN is useful in detecting prerenal AKI in children administered furosemide.

Effectiveness of Trivalent Inactivated Influenza Vaccine in Children Estimated by a Test-Negative Case-Control Design Study Based on Influenza Rapid Diagnostic Test Results

We assessed vaccine effectiveness (VE) against medically attended, laboratory-confirmed influenza in children 6 months to 15 years of age in 22 hospitals in Japan during the 2013-14 season. Our study was conducted according to a test-negative case-control design based on influenza rapid diagnostic test (IRDT) results. Outpatients who came to our clinics with a fever of 38 °C or over and had undergone an IRDT were enrolled in this study. Patients with positive IRDT results were recorded as cases, and patients with negative results were recorded as controls. Between November 2013 and March 2014, a total of 4727 pediatric patients (6 months to 15 years of age) were enrolled: 876 were positive for influenza A, 66 for A(H1N1)pdm09 and in the other 810 the subtype was unknown; 1405 were positive for influenza B; and 2445 were negative for influenza. Overall VE was 46% (95% confidence interval [CI], 39-52). Adjusted VE against influenza A, influenza A(H1N1)pdm09, and influenza B was 63% (95% CI, 56-69), 77% (95% CI, 59-87), and 26% (95% CI, 14-36), respectively. Influenza vaccine was not effective against either influenza A or influenza B in infants 6 to 11 months of age. Two doses of influenza vaccine provided better protection against influenza A infection than a single dose did. VE against hospitalization influenza A infection was 76%. Influenza vaccine was effective against influenza A, especially against influenza A(H1N1)pdm09, but was much less effective against influenza B.

Catheter-related blood stream infection caused by Dermacoccus barathri, representing the first case of Dermacoccus infection in humans

A 7-year-old boy undergoing home parenteral nutrition with totally implantable central venous access device for chronic intestinal pseudo-obstruction experienced repeated episodes of fever with a temperature above 39.0 °C despite the antibiotic treatment. The fever was considered to be catheter-related blood stream infections, as no other etiology could be justified. Repeated blood culture tests revealed negative after 1-week incubation, whereas some samples of blood collected from the central venous catheter yielded positive and gram-positive rods were detected. These bacteria were detected repeatedly, then the central venous access device was removed with consideration for the possibility of this bacteria being a pathogen. Thereafter, the fever did not recur and the blood culture tests were negative. The causative agent was identified as Dermacoccus barathri based on the 16S rRNA gene sequence and phylogenetic analysis of 6118-bp concatenated sequences of 4 housekeeping genes. Genus Dermacoccus are one form of Actinomycetes isolated from human skin and water, but human infection with Dermacoccus spp. has not been previously reported and the pathogenicity of the bacteria remains unclear. To our knowledge, this is the first reported case of Dermacoccus infection in humans.

High rate of inducible clindamycin resistance in Staphylococcus aureus isolates--a multicenter study in Tokyo, Japan

The resistance of Staphylococcus aureus (S. aureus) to antibiotics is an increasing problem. Clindamycin has been used as empiric therapy for the rising incidence of community-acquired methicillin-resistant S. aureus (MRSA). As such, the local rate of inducible resistance against clindamycin is an important consideration. This multicenter study was conducted to identify the incidence of inducible clindamycin resistance of S. aureus isolates in Tokyo, the most populous city in Japan. A total of 2408 adult and pediatric samples were collected from a university hospital and two pediatric hospitals between January 2011 and December 2011. Among the 2341 samples analyzed, the incidence of inducible clindamycin resistance in erythromycin-resistant and clindamycin-susceptible/intermediate isolates was found to be 91% (n = 585), a figure much higher compared to most reports from other countries. In conclusion, we found a very high rate of inducible clindamycin resistance in macrolide-resistant S. aureus isolates in our geographic area.

Clinical features of bacteremia due to Campylobacter jejuni

OBJECTIVE

The clinical features of bacteremia due to Campylobacter jejuni (C. jejuni) have yet to be fully elucidated.

METHODS AND RESULTS

The cases of C. jejuni bacteremia were retrospectively reviewed during a twelve-year period in a single institute. C. jejuni was identified in 7 patients through blood cultures, and disease onset occurred between June and October. Except for 2 previously healthy individuals, 5 patients had underlying diseases (chronic liver diseases, n=3; hematological malignancies, n=2). All patients were febrile, but 2 patients did not present with gastrointestinal symptoms. C. jejuni isolates were susceptible to gentamicin and macrolides, but about half of them were resistant to fluoroquinolones. Disease outcomes were favorable, and no deaths related to C. jejuni bacteremia were observed.

CONCLUSION

These results suggest that C. jejuni bacteremia could occur primarily or secondarily to gastroenteritis with a seasonal peak and that prognosis would be favorable regardless of the underlying diseases.

Safety and efficacy of linezolid in 16 infants and children in Japan

Linezolid, an oxazolidinone antibiotic, exhibits a broad spectrum of activity against Gram-positive bacteria. It has been licensed for adult use in Japan since 2006 for MRSA infections, and has also been used off-label for pediatric patients. At our university hospital, a total of 16 infants and children (including one non-Japanese Asian) were administered linezolid owing to infection with multidrug-resistant Gram-positive bacteria, after consent had been provided. All patients had severe underlying diseases or indications for surgery. Eighty-eight percent of the causal microorganisms were methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-resistant coagulase-negative Staphylococcus and all were sensitive to linezolid. Linezolid was administered because the antecedent anti-MRSA medications were ineffective or contraindicated, or intravenous-to-oral switch therapy was requested owing to cardiac or orthopedic surgical-site infections. The median duration of administration was 13 days (range 3-31 days). The overall efficacy was 91 % (10/11) in those for whom efficacy could be evaluated. Only two patients (both teen-aged) encountered linezolid-related adverse effects (13 %, 2/16). One patient showed elevation of liver enzymes (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]), requiring that administration be withdrawn, but enzyme levels returned to normal after the patient had been switched to vancomycin. The other patient showed transiently decreased platelet counts. Linezolid is considered generally safe and effective for children in Japan, especially for those who cannot use other anti-MRSA medications or those who require oral antibiotics for infections with multidrug-resistant Gram-positive bacteria.

Influenza-related mortality trends in Japanese and American seniors: evidence for the indirect mortality benefits of vaccinating schoolchildren

BACKGROUND

The historical Japanese influenza vaccination program targeted at schoolchildren provides a unique opportunity to evaluate the indirect benefits of vaccinating high-transmitter groups to mitigate disease burden among seniors. Here we characterize the indirect mortality benefits of vaccinating schoolchildren based on data from Japan and the US.

METHODS

We compared age-specific influenza-related excess mortality rates in Japanese seniors aged ≥65 years during the schoolchildren vaccination program (1978-1994) and after the program was discontinued (1995-2006). Indirect vaccine benefits were adjusted for demographic changes, socioeconomics and dominant influenza subtype; US mortality data were used as a control.

RESULTS

We estimate that the schoolchildren vaccination program conferred a 36% adjusted mortality reduction among Japanese seniors (95%CI: 17-51%), corresponding to ∼1,000 senior deaths averted by vaccination annually (95%CI: 400-1,800). In contrast, influenza-related mortality did not change among US seniors, despite increasing vaccine coverage in this population.

CONCLUSIONS

The Japanese schoolchildren vaccination program was associated with substantial indirect mortality benefits in seniors.

Effective and safe immunizations with live-attenuated vaccines for children after living donor liver transplantation

Immunizations using live-attenuated vaccines are not recommended for post-liver transplant children due to its theoretical risks. However, they will encounter vaccine-preventable viral diseases upon returning to real-life situations. We performed a total of 70 immunizations with four individual live-attenuated vaccines to 18 pediatric post-living donor liver transplant (LDLT) recipients who fulfilled a clinical criteria including humoral and cell-mediated immunity. The seroconversion rates at the first dose for measles (strain AIK-C), rubella (strain TO-336), varicella (strain Oka), and mumps (strains Hoshino) were 100% (15/15), 100% (15/15), 82% (9/11), and 82% (9/11), respectively. During observed period (-5 years 11 months), a few cases with waning immunity (antibodies were once produced but the levels fell over time) were seen except after rubella immunization. Clinical diseases after seroconversion or definite serious adverse effects due to immunization were not observed. Immunizations using selected live-attenuated vaccines were safe and effective for post-LDLT children who were not severely immunosuppressed.

[Effect of post-exposure prophylaxis with oseltamivir for those in contacts with influenza patients in pediatric wards]

During the influenza season, outbreaks of influenza may occur in the pediatric wards due to spread from the patients hospitalized with influenza, or from those hospitalized during the latency period and develop influenza afterwards. Post-exposure prophylaxis with neuraminidase inhibitors has been reported to be effective in preventing outbreaks among household members and nursing home residents. However, for nosocomial spread, its effectiveness and possible adverse effects are to be determined. During the 2002/2003 influenza season, we experienced a total of 3 nosocomial outbreaks of influenza in the pediatric wards in two hospitals in the Kanto district, Japan. Since the number of contacts who developed influenza had been increasing despite the isolation precaution implemented, post-exposure prophylaxis with oseltamivir (2 mg/kg/dose, maximum 75 mg/dose, once a day for 7-10 days) was implemented with a permission from the parents to terminate the outbreaks. In the outbreaks (one with influenza A, two with influenza B), a total of 29 inpatients had contact with influenza patients: among those 29, 13 were given post-exposure prophylaxis, 16 were not. Out of 16 patients who did not receive post-exposure prophylaxis, 11 (69%) developed influenza: out of 13 with post-exposure prophylaxis, none developed influenza. Those patients who developed influenza were given oseltamivir (2 mg/kg/dose, maximum 75 mg/dose, twice a day for 5 days) and accommodated in a private room or a room with other patients with influenza of the same type. No significant adverse effects due to oseltamivir were observed among those who were enrolled in this study.