[Results of Booster Vaccination in Children with Primary Vaccine Failure after Initial Varicella Vaccination].

In October 2014, the varicella vaccination policy in Japan was changed from a single voluntary inoculation to two routine inoculations. This paper reports the results of booster vaccination in children who did not show seroconversion after initial vaccination (i.e., primary vaccine failure : PVF) over a 7-year period prior to the introduction of routine varicella vaccination. Between November 2007 and May 2014, 273 healthy children aged between 1.1 and 14.5 years (median : 1.7 years) underwent varicella vaccination. Before and 4 to 6 weeks after vaccination, the antibody titers were measured using an immune adherence hemagglutination (IAHA) assay and a glycoprotein-based enzyme-linked immunosorbent assay (gpELISA). In addition, side reactions were examined during the four-week period after vaccination. Children who did not show IAHA seroconversion (PVF) were recommended to receive a booster vaccination, and the measurement of antibody titers and an assessment of side reactions were performed after the booster dose. In May 2015, a questionnaire was mailed to each of the 273 participants to investigate whether they had developed varicella and/or herpes zoster after vaccination. After initial vaccination, the IAHA seroconversion rate was 75% and the mean antibody titer (Log2) with seroconversion was 4.7, while the gpELISA seroconversion rate was 84% and the mean antibody titer (Log10) with seroconversion was 2.4. Among children with PVF, 54 received booster vaccination within 81 to 714 days (median : 139 days) after the initial vaccination. After booster vaccination, the IAHA seroconversion rate was 98% and the mean antibody titer (Log2) with seroconversion was 5.8. Both the seroconversion rate and the antibody titer were higher compared with the values after the initial vaccination (p < 0.01). After booster vaccination, the gpELISA seropositive rate was 100% and the mean positive antibody titer (Log 10) was 3.6 ; similar results were obtained for the IAHA assay, with a significantly higher, antibody response than that after the initial vaccination (p < 0.01). Side reactions were generally minor, including fever (≥ 37.5 degrees C), rash at the injection site, and rash at other sites. There were no significant differences in the incidences of side reactions between the initial and booster vaccinations. A total of 185 participants responded to the questionnaire (response rate : 68%), and the period between receiving the initial vaccination and their response to the questionnaire ranged from 1.0 to 7.5 years (median : 4.0 years). The prevalence of breakthrough varicella after the initial vaccination was 17% among seroconverters who did not receive booster vaccination and 14% among non-seroconverters who received booster vaccination, showing no significant difference between the two groups. In conclusion, there are no safety issues regarding the administration of a booster vaccination to children with PVF after an initial varicella vaccination, and,a good antibody response can be expected.

Evaluation of varicella zoster virus-specific cell-mediated immunity by using an interferon-γ enzyme-linked immunosorbent assay.

BACKGROUND: Administration of the varicella vaccine induces both varicella-zoster virus (VZV)-specific humoral and cell-mediated immunity (CMI). OBJECTIVE: To assess VZV-CMI, we developed an interferon γ enzyme-linked immunosorbent assay (IFN-γ ELISA) that measures the quantity of total IFN-γ in culture supernatants of human peripheral blood mononuclear cells. STUDY DESIGN: We evaluated this method by comparing the pre- and post-vaccination immune response in peripheral blood mononuclear cells of 30 healthy children who were administered an initial varicella vaccination at Konan Kosei hospital. RESULTS: IFN-γ ELISA showed well-validated results; CMI was not detectable pre-immunization but became detectable post-immunization. Seroconversion was detected in 92.6% of subjects by the immune adherence hemagglutination test; however, half of the subjects did not display an increase in CMI levels. We also compared the incidence of breakthrough varicella and herpes zoster development between CMI post-positive and post-negative vaccinees at 1-2years after the last VZV vaccination. Eight subjects had a history of varicella or herpes zoster exposure post-VZV vaccination. Two of them with post-negative CMI contracted breakthrough varicella 15-16months after the last vaccination, even though they had sufficient VZV-specific antibody levels to be considered seropositive and seroprotected. Conversely, the others with post-positive CMI did not contract breakthrough varicella, despite experiencing extensive VZV exposure through casual contact with playmates and family. CONCLUSIONS: The CMI data generated by this IFN-γ ELISA may accurately reflect real-world immune status, and CMI may be closely related to immunoprotection against breakthrough varicella development.

Assessment of the loop-mediated isothermal amplification assay for rapid diagnosis of Mycoplasma pneumoniae in pediatric community-acquired pneumonia.

Rapid diagnosis of Mycoplasma pneumoniae pneumonia is required for timely treatment with effective antibiotics; however, PCR-based methods are often too expensive and technologically intensive for general use in clinical practice. In this study, the efficacy of the loop-mediated isothermal amplification (LAMP) assay for diagnosis of M. pneumoniae pneumonia in clinical practice was prospectively evaluated. From July 2011 to March 2012, 531 children hospitalized for community-acquired pneumonia were enrolled. In all patients, throat swabs were obtained on admission for the detection of M. pneumoniae DNA, and paired serum samples were obtained to assay M. pneumoniae particle agglutination (PA) antibody titers. M. pneumoniae pneumonia was diagnosed by either a positive LAMP assay or an increase of 4-fold or greater in the PA titer. Overall, 271 children (51.0% of the patients with pneumonia) were diagnosed with M. pneumoniae pneumonia. Among these, 258 (95.2%) and 248 (91.5%) were identified by the LAMP assay and serological tests, respectively. When the results of serological tests were considered as standard, the sensitivity, specificity, and positive and negative predictive values of the LAMP assay were 94.8%, 91.9%, and 91.1% and 95.2%, respectively. The median duration of pharyngeal carriage, as measured by the LAMP assay, was 9.5 days. Thus, the LAMP assay is useful in the rapid diagnosis of M. pneumoniae pneumonia.

[Immunogenicity of additional varicella vaccination 3-5 years after the initial vaccination].

Additional varicella vaccination was carried out targeting 16 subjects who had immune adherence hemagglutination (IAHA) seroconversion following the initial varicella vaccination and did not contract breakthrough varicella after the initial vaccination. The median ages at the initial and additional vaccination were 2.1 (1.1-6.9) years old and 6.1 (4.4-10.5) years old, respectively. The mean interval between the initial and additional vaccination was 4.0 (3.2-5.2) years. IAHA and glycoprotein-based enzyme-linked immunosorbent assay (gpELISA) antibody titers were measured just before and 4-6 weeks after the additional vaccination. Side reaction was surveyed at four weeks after the additional vaccination, and compared with the results at the initial vaccination. IAHA and gpELISA seroconversion rates at the initial vaccination were 100% and 88% respectively. Prior to the additional vaccination, IAHA antibody titers significantly decreased in 50% of the subjects, and became negative in 38% of the subjects. On the other hand, a significant increase in IAHA antibody titers was observed in 25% of the subjects, and this is assumed to be the result of a subclinical infection after the initial vaccination. The positive rate of both antibodies after the additional vaccination was 100%, the mean IAHA antibody titer (Log2) after the initial/additional vaccination in seropositive subjects was 4.6/6.5, and the mean gpELISA antibody titer (Log10) was 2.3/4.0. The mean IAHA and gpELISA antibody titers were higher after the additional vaccination than after the initial vaccination (p < 0.01, p < 0.01). This is considered to be the booster effect due to the additional vaccination. At 0-2 days after the additional vaccination, a rash at the injection site was observed in 56% of the subjects, higher than the incidence after the initial vaccination (13%) (p < 0.05), but no severe systemic side reactions were observed at either the initial or the additional vaccination. In conclusion, an additional varicella vaccination 3-5 years after the initial vaccination is thought to have greater immunogenicity and is considered effective.

[Multicenter surveillance of Pseudomonas aeruginosa strains for antimicrobials in Aichi prefecture in 2009].

We investigated the susceptibility to antimicrobials of 204 Pseudomonas aeruginosa strains isolated from 21 hospitals in Aichi prefecture from September to November 2009. MIC distributions of various antimicrobials were analyzed in terms of geographic region of isolation, patient status (outpatient or inpatient), and type of specimens that the strain was isolated from. The results were as follows. 1. Although more than 90% of strains were susceptible to all aminoglycosides and colistin, 80-90% of them were susceptible to beta-lactams and fluoroquinolones. MIC distributions of all antimicrobials measured were not significantly different between regions. 2. Only 1 strain (0.5%) was multi-drug resistant Pseudomonas aeruginosa (MDRP). Thirteen strains (6.4%) showed imipenem MIC > or = 16 microg/mL, and 16 strains (7.8%) showed ciprofloxacin MIC > or = 4 microg/mL. These strains tended to be more isolated from urine, respiratory tract specimens, or surgical specimens. 3. The MICs of tazobactam/piperacillin, panipenem, meropenem, doripenem, biapenem, sulbactam/cefoperazone, cefepime, and aztreonam were significantly higher in strains isolated from inpatients than in those from outpatients. MIC distributions of antimicrobials other than beta-lactams were not significantly different between situations where strains were isolated. 4. MIC distributions of piperacillin, all carbapenems, cefepime, gentamicin, and all fluoroquinolones were significantly different among samples from which strains were isolated. The strains isolated from blood showed lower MICs against all antimicrobials than those from other samples. No difference was found in MIC distributions when categorized according to bacteremic origin. The MICs were apparently elevated against beta-lactams, fluoroquinolones, and gentamicin in strains isolated from respiratory tract specimens, and against beta-lactams, and fluoroquinolones in strains isolated from urine. It was suggested that in P. aeruginosa surveillance, the results should be reported by stratifying with patient status, and type of specimens that the strain was isolated from and that regional surveillance should be useful with such stratification to establish antibiograms for empirical antimicrobial choice.

Detection of Mycoplasma pneumoniae by loop-mediated isothermal amplification (LAMP) assay and serology in pediatric community-acquired pneumonia.

Rapid diagnosis of Mycoplasma pneumoniae pneumonia is required for treatment with effective antimicrobial agents without delay; however, this capacity has not yet been established in clinical practice. Recently, a novel nucleic acid amplification method termed loop-mediated isothermal amplification (LAMP) has been used to rapidly diagnose various infectious diseases. In this study, we prospectively evaluated the efficacy of the LAMP assay to rapidly diagnose M. pneumoniae pneumonia in clinical practice. Three hundred sixty-eight children (median age, 3.8 years; range, 0.1-14.3 years) admitted to our hospital between April 2009 and March 2010 for community-acquired pneumonia were enrolled in this study. We obtained throat swabs on admission to detect M. pneumoniae DNA and paired serum samples on admission and at discharge to assay M. pneumoniae antibody titers. M. pneumoniae pneumonia was diagnosed by either a positive LAMP assay or a fourfold or greater increase in antibody titer. Overall, 46 children (12.5% of the patients with pneumonia) were diagnosed with M. pneumoniae pneumonia; of these, 27 (58.7%) were aged less than 6 years. Of the aforementioned 46 children, 38 (82.6%) and 37 (80.4%) were identified by LAMP and serology, respectively. When the results of serology were taken as the standard, the sensitivity and specificity and positive and negative predictive values of the LAMP assay were 78.4%, 97.3%, 76.3%, and 97.6%, respectively. We concluded the LAMP assay may be useful for rapid diagnosis of M. pneumoniae pneumonia.

[A study for the necessity of virus titer of varicella vaccine presently used].

Recently available varicella vaccine titers are several dozen times higher than the formulation standard in accompanying information, i.e., > or = 1,000 PFU/dose. We investigated changes in immunogenicity associated with vaccination using a reduced dose whose virus titer was close to that used when the vaccine was developed, and examined the need for the virus titer presently used. In a non blinded study of 43 children with no history of varicella infection, we administered 0.1 mL of varicella vaccine (1/5 of the normal dose) to 20 children 1 year 0 month to 4 years 5 months old (median: 1 year 5 months) and the standard 0.5mL dose to 23 children 1 year 2 months to 3 years 7 months old (median: 1 year 9 months). We measured IAHA and gpELISA antibody titer before vaccination and 4 to 6 weeks after vaccination. We defined "positive" as > or = 2 fold of IAHA titer and > or = 50 U of gpELISA antibody titer. We administered an additional 0.5mL of varicella vaccine to children whose IAHA titer failed to show seroconversion and remeasured antibody titer 4 to 6 weeks after revaccination. IAHA seroconversion was 25.0% (5/20) and gpELISA seroconversion 55.0% (11/20) in the 0.1 mL vaccination group, which was lower than that of 76.2% (16/21) and 87.0% (20/23), IAHA p < 0.01, gpELISA p < 0.05, in the 0.5 mL vaccination group. We administered an additional vaccination to 19 children--15 in the 0.1 mL vaccination group and 4 in the 0.5 mL vaccination group-with 100% seroconversion for both methods. Mean antibody titer after revaccination in the 0.1 mL vaccination group (IAHA 2 (6.0), gpELISA 10 (3.7)) was higher than those in the 0.5mL vaccination group who seroconverted following initial vaccination (IAHA 2(4.5), gpELISA 10(2.6)) (p < 0.01). We also measured virus titer in the remaining vaccine following vaccination of 0.1 mL (n = 20), and estimated virus titer administered to the 0.1 mL vaccination group to be 2,600-6,400 PFU/ dose. Varicella vaccine immunogenicity decreased if dosage was reduced to 1/5 of the standard dose, indicating that the present virus titer is necessary to maintain adequate immunogenicity. An additional administration of the standard dose to children who failed to seroconvert after initial 0.1 mL administration produced high antibody titers thought to constitute a booster effect.

[Phases 3 and 4 immunization immunogenicity with combined measles-rubella vaccine].

A two-phase combined measles-rubella vaccine (MR) immunization schedule was introduced for age 1 and prior to primary school entry in Japan in April 2006. Further immunization was also introduced for 13 (Phase 3) and 18-year-old (Phase 4) cohorts for the 5-year period from April 2008 to March 2013. We surveyed Phases 3 and 4 MR immunization immunogenicity and safety. From August 2007 to December 2009, we conducted 3 Phase 3 and 15 Phase 4 immunizations. We then took paired serum samples (pre- and 4-6 weeks post-immunization), and measured measles antibody titers using hemagglutination inhibition (HI) and neutralizing test (NT), and rubella antibody titers using HI. Pre-positive measles HI antibody titer (> or = 8) was 72% (13/18) and pre-positive measles NT antibody titer (> or = 2) was 100% (18/18). Post-positive measles HI and NT antibody titers were 94% (17/18) and 100% (18/18). Mean post-immunization measles HI and NT antibody titers were significantly higher than pre-titers, with four-fold or greater increases seen in 9 (50%) and 6 (33%) subjects. Pre-positive rubella HI antibody titer (> or = 8) was 94% (17/18), and post-positive rubella HI antibody titer 100% (18/18). Mean post-immunization rubella HI antibody titer was significantly higher than pre-titer, with four-fold or greater increases seen in 8 subjects (44%). Paired HI antibody titers were measured in pre- and post-Phase 1 immunization for measles in 3 subjects and for rubella in 2 subjects. Those with post-Phase 1 measles HI antibody titers of 32, 64, and 128 yielded titers of 16, 8, and < 8 pre-Phase 3 or Phase 4 immunization, showing antibody reduction or seronegative conversion. Those with post-Phase 1 rubella HI antibody titers of 128 and 256 yielded titers of 64 and 32 in pre-Phase 4 immunization, showing antibody reduction. Seroconversion or four-fold or greater increases in titer were seen post-immunization in 60% (3/5) of these subjects. A clinical reaction survey of all subjects 4 weeks post-immunization, showed only 1 case of mild fever and no local or systemic adverse reactions such as generalized urticaria or anaphylaxis. In conclusion, Phases 3 and 4 MR immunogenicity was satisfactory.

Community-acquired Acinetobacter baumannii meningitis in a previously healthy 14-month-old boy.

We report a previously healthy 14-month-old boy who developed community-acquired Acinetobacter baumannii meningitis. He had no history of immunodeficiency, and was brought to Konan Kosei Hospital with a high fever and vomiting. His consciousness was clear, but neck stiffness was noted. Examination of the cerebrospinal fluid (CSF) revealed a cell count of 10 112/microl; protein, 216 mg/dl; and glucose, 9 mg/dl. A CSF test kit for bacterial capsular antigens (Pastorex Meningitis; Bio-Rad Laboratories) was positive for Haemophilus influenzae type b antigen. On day 3 of admission, the microorganism isolated by CSF culture was identified as A. baumannii. Therefore, his treatment was changed to meropenem hydrate from the initial therapy with panipenem/betamipron and ceftriaxone sodium hydrate. Because the CSF cell count remained elevated, meropenem hydrate was administered for a total of 19 days. The meningitis resolved with no sequelae.

T serotypes and antimicrobial susceptibilities of group A streptococcus isolates from pediatric pharyngotonsillitis.

Group A streptococcus (GAS) is a major cause of pediatric pharyngotonsillitis. In this study we determined the T serotype and antimicrobial susceptibility of GAS isolates from Japanese children. From January to December 2006, a total of 438 isolates of GAS were obtained from pharyngeal swabs of 438 children with pharyngotonsillitis. The commonest T serotype was type 1 (110 strains, 25.1%), followed by type 12 (107, 24.4%) and type 4 (77, 17.6%). All GAS isolated from pharyngeal swabs were susceptible to beta-lactams (benzylpenicillin, amoxicillin, cefotaxime, ceftriaxone, imipenem, panipenem, and cefditoren) and vancomycin, but 19.6, 19.6, 3.2, 11.6, and 27.6% were resistant to erythromycin, clarithromycin, clindamycin, minocycline, and norfloxacin, respectively. Resistance varied considerably with the T serotype. In particular, type 4 isolates had the highest resistance (67.5, 67.5, 26.0, and 53.2% were resistant to erythromycin, clarithromycin, minocycline, and norfloxacin, respectively).

DNA sequence analysis of varicella-zoster virus gene 62 from subclinical infections in healthy children immunized with the Oka varicella vaccine.

A live attenuated varicella vaccine, the Oka vaccine strain (vOka), is routinely administered to children in Japan and other countries, including the United States. vOka consists of a mixture of genotypically distinct variants, but little is known about the growth potential of each variants in vivo. We isolated varicella-zoster virus (VZV) DNA sequences from the peripheral blood mononuclear cells (PBMCs) of asymptomatic healthy children immunized with the Oka varicella vaccine. VZV gene 62 DNA fragments were detected in 5 of 166 (3.0%) PBMC samples by nested PCR within 5 weeks of the vaccination. Sequence analysis of VZV DNA from these five PBMC samples indicated that multiple viral clones in the vaccine could infect vaccinees and replicate in vivo. We also provide evidence that a nonsynonymous substitution at position 105356 may affect viral replication in vivo.

Five-day oral cefditoren pivoxil versus 10-day oral amoxicillin for pediatric group A streptococcal pharyngotonsillitis.

We prospectively compared the efficacy of oral cefditoren-pivoxil and conventional oral amoxicillin for pharyngotonsillitis caused by group A streptococcus in children. Either oral cefditoren-pivoxil (3 mg/kg t.i.d. for 5 days) or amoxicillin (10 mg/kg t.i.d. for 10 days) was administered to patients with group A streptococcal pharyngotonsillitis attending the pediatric outpatient clinic of Showa Hospital (Konan, Japan) between January and December 2006. Diagnosis was based on isolation of bacteria from a pharyngeal swab. Culture was always done to confirm eradication, and urinalysis and follow-up were performed at least once weekly for 4 weeks. Among 258 patients, 103 (aged 5.5 +/- 2.3 years) received cefditoren-pivoxil and 155 (aged 5.2 +/- 2.0 years) received amoxicillin. There were no significant between-group differences in age, sex, or symptoms. Eradication was confirmed in 99% (102/103) of the cefditoren-pivoxil group and 100% of the amoxicillin group. Recurrence within 4 weeks occurred in 8 and 15 patients in the cefditoren-pivoxil and amoxicillin groups, respectively, showing no significant difference in the recurrence rate, and all isolates had the same serotypes as before. There were no clinically significant adverse reactions or complications. The 50%/90% minimum inhibitory concentrations (microg/ml) of cefditoren-pivoxil and amoxicillin for the 258 isolates were < or =0.03/< or =0.03 and < or =0.03/0.06, respectively, so all isolates were susceptible to both agents. Because the efficacy for pediatric group A streptococcus pharyngotonsillitis was similar between oral cefditoren-pivoxil for 5 days and amoxicillin for 10 days, the shorter treatment period may make the former regimen preferable.

Utility of a rapid diagnosis kit for Mycoplasma pneumoniae pneumonia in children, and the antimicrobial susceptibility of the isolates.

We evaluated a kit for the rapid diagnosis of Mycoplasma pneumoniae infection and investigated the antimicrobial susceptibility of the isolates. A total of 194 otherwise healthy children, aged 0.3-14.9 years, were diagnosed as having pneumonia by chest X-ray findings between December 2003 and November 2004, and were admitted to Showa Hospital. Isolation of M. pneumoniae was attempted from a throat swab obtained on admission, and the complement fixation titer was measured in paired serum samples obtained at admission and at the convalescent stage. We also used a rapid diagnosis kit (ImmunoCard Mycoplasma) for the detection of specific immunoglobulin M antibody in paired sera. Pneumonia due to M. pneumoniae was defined by isolation of this microorganism, or by seroconversion, or a >or=4-fold increase in the antibody titer. Using each isolate, we determined the minimum inhibitory concentrations for five antimicrobial agents by the broth dilution method. M. pneumoniae pneumonia was diagnosed in 45 children (23.2%). The ImmunoCard had a sensitivity of 31.8% using admission serum and 88.6% using paired sera, while the specificity was 78.1% and 70.5%, respectively. M. pneumoniae was isolated from 14 of the 45 patients (31.1%). The 50%/90% minimum inhibitory concentration (microg/ml) of erythromycin, clarithromycin, azithromycin, minocycline, and levofloxacin was 0.006/0.012,

[Systemic infection of Aspergillus flavus in a patient with acute lymphoblastic leukemia].

A 57-year-old woman with acute lymphoblastic leukemia (ALL) developed an antibiotics-resistant fever after remission induction therapy. Chest X-ray and computed tomography scan revealed multiple consolidations and cavities. Successively, numerous subcutaneous nodules and a thyroid mass emerged. Aspergillus flavus (A. flavus) was cultured from both sites. Despite the patient's granulocyte recovery, the fever persisted and multiorgan function deteriorated rapidly. However, she was successfully treated with intensive supportive therapy including continuous hemodialysis and filtration. Prolonged use of amphoterin B and itraconazole failed to cure her aspergillosis, but the illness remained indolent thereafter.