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.

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.

Low prevalence of Chlamydia pneumoniae infections during the Mycoplasma pneumoniae epidemic season: Results of nationwide surveillance in Japan.

OBJECTIVE: Chlamydia pneumoniae and Mycoplasma pneumoniae are both common causes of atypical pneumonia. We conducted an annual national survey of Japanese children to screen them for C. pneumoniae infections during the M. pneumoniae epidemic season. METHODS: Nasopharyngeal swab specimens were collected from children aged 0-15 years with suspected acute lower respiratory tract infection due to atypical pathogens, at 85 medical facilities in Japan from June 2008 to March 2018. Specimens were tested for infection using real-time polymerase chain reaction assays. RESULTS: Of 5002 specimens tested, 1822 (36.5%) were positive for M. pneumoniae alone, 42 (0.8%) were positive for C. pneumoniae alone, and 20 (0.4%) were positive for both organisms. In children with C. pneumoniae infection, the median C. pneumoniae DNA copy number was higher in those with single infections than in those with M. pneumoniae coinfection (p = 0.08); however it did not differ significantly according to whether the children had received antibiotics prior to sample collection (p = 0.34). CONCLUSIONS: The prevalence of C. pneumoniae infection was substantially lower than that of M. pneumoniae infection during the study period. The change in prevalence of C. pneumoniae was not influenced by that of M. pneumoniae. Children with single C. pneumoniae infection are likely to have had C. pneumoniae infection, while those with coinfection are likely to have been C. pneumoniae carriers.

Comparing Antimicrobial Susceptibilities among Mycoplasma pneumoniae Isolates from Pediatric Patients in Japan between Two Recent Epidemic Periods.

We compared the antimicrobial susceptibility of Mycoplasma pneumoniae isolates from pediatric patients in Japan in 2011-2012 and 2015-2016, when epidemics occurred. The antimicrobial activity of macrolides and tetracyclines against M. pneumoniae infection tended to be restored in 2015-2016. There was no change in the antimicrobial activity of quinolones against M. pneumoniae infection.

Novel neuroblastoma amplified sequence (NBAS) mutations in a Japanese boy with fever-triggered recurrent acute liver failure.

Biallelic mutations in the neuroblastoma amplified sequence (NBAS) gene have been reported to cause two different clinical spectra: short stature with optic nerve atrophy and Pelger-Huët anomaly (SOPH) syndrome and infantile liver failure syndrome 2 (ILFS2). Here, we describe a case of a 3-year-old Japanese boy who presented with fever-triggered recurrent acute liver failure (ALF). The clinical characteristics were considerable elevation of liver enzymes, severe coagulopathy, and acute renal failure. In addition to the liver phenotype, he had short stature and Pelger-Huët anomaly in the peripheral granulocytes. Whole-exome and Sanger sequencing of the patient and his parents revealed that he carried novel compound heterozygous missense mutations in NBAS, c.1018G>C (p.Gly340Arg) and c.2674 G>T (p.Val892Phe). Both mutations affect evolutionarily conserved amino acid residues and are predicted to be highly damaging. Immunoblot analysis of the patient's skin fibroblasts showed a normal NBAS protein level but a reduced protein level of its interaction partner, p31, involved in Golgi-to-endoplasmic reticulum retrograde vesicular trafficking. We recommend NBAS gene analysis in children with unexplained fever-triggered recurrent ALF or liver dysfunction. Early antipyretic therapy may prevent further episodes of ALF.

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.

Incidence of Viremia With DNA Viruses in Oncology Patients With Febrile Neutropenia.

BACKGROUND: Although febrile neutropenia (FN) is one of the most common adverse events produced by chemotherapy, its microbiological etiology is determined for only 15% to 30% of cases. OBJECTIVES: We investigated the rate of viremia with common DNA viruses in patients with FN. STUDY DESIGN: From June 2012 to April 2014, 72 blood samples from 24 patients receiving chemotherapy, who experienced FN episodes, were examined for the presence of herpes viruses and other DNA viruses. We used real-time polymerase chain reaction assays to detect herpes simplex virus type 1 and 2, varicella zoster virus, Epstein-Barr virus, cytomegalovirus, human herpes virus types 6 and 7, BK virus and human parvovirus B19 (B19). RESULTS: Viruses were identified in 14 of 72 samples (19.4%). The detected etiological agents were BK virus (5 episodes), human herpes virus type 6 (4 episodes), B19 (4 episodes), Epstein-Barr virus (2 episodes), and cytomegalovirus (1 episode). CONCLUSIONS: Our results indicate that viral infections are common causes in patients with FN. Therefore, viruses may be responsible for FN in a large proportion of patients in whom a causative microorganism could not be identified, and this viral etiology may explain their poor response to antibiotic therapy.

Cancer Management in Kabuki Syndrome: The First Case of Wilms Tumor and a Literature Review.

A 3-year-old Japanese girl treated for hypoplastic left heart syndrome and Dandy-Walker syndrome was diagnosed with Kabuki syndrome (KS) with a mutation of KMT2D; c.13285C>T:p.Q4429*. Concurrently, macrohematuria portended the diagnosis of Wilms tumor. Postoperative chemotherapy has achieved complete remission despite a prolonged and reduced regimen due to liver dysfunction and convulsions. Cancer predisposition has been suggested for KS due to oncogenic mutations in KMT2D or KDM6A. The first case of nephroblastoma exemplified the treatability of malignancies in KS patients, as shown in the 9 cases reviewed. Active screening and intervention are recommended for the cure of malignancy in KS children.

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.

Clinical efficacy of cycling empirical antibiotic therapy for febrile neutropenia in pediatric cancer patients.

BACKGROUND: Febrile neutropenia (FN) is the main treatment-related cause of mortality among children with cancer, as the prolonged use of broad-spectrum antibiotics can lead to antibiotic resistance in these patients. Antibiotic cycling has been reported to limit the emergence of antibiotic-resistant bacteria among adult patients. However, no studies have evaluated pediatric patients with FN. METHODS: Between September 2011 and February 2014, 126 pediatric cancer patients were admitted to our center for chemotherapy and/or hematopoietic stem cell transplantation and were included in this study. Retrospective and prospective data collection were performed before and after antibiotic cycling, respectively. Between September 2011 and November 2012 (before antibiotic cycling was implemented), intravenous cefpirome was used as the empirical therapy for FN. Between December 2012 and February 2014 (after antibiotic cycling was implemented), the monthly antibiotic cycling involved intravenous piperacillin-tazobactam (PIPC/TAZ), intravenous meropenem or ciprofloxacin (CPFX), and intravenous cefepime in that order. For children aged ≥13 years, the monthly cycling involved intravenous PIPC/TAZ, and CPFX was administered. RESULTS: The detection rates for extended-spectrum ß-lactamase producers in blood and stool culture samples decreased significantly after the implementation of antibiotic cycling (0.33/1000 patient-days vs 0/1000 patient-days, p = 0.03; 1.00/1000 patient-days vs 0/1000 patient-days, p < 0.01; respectively). CONCLUSION: Antibiotic cycling was associated with a decreased emergence of multidrug-resistant microbes.

Activated phosphoinositide 3-kinase δ syndrome presenting with gut-associated T-cell lymphoproliferative disease.

A 13-year-old boy was admitted to our hospital because of persistent diarrhea, abdominal pain, and bloody stools. The patient had experienced repeated hospitalizations for the treatment of respiratory infections since early childhood. Colonoscopic and pathological studies led to a diagnosis of gut-associated T-cell lymphoproliferative disease (T-cell LPD). Laboratory data showed T-lymphocytopenia (492/µl), increased serum IgG levels (1,984 mg/dl), and low serum antibody titers for specific pathogens. Combined immunodeficiency accompanied by T-LPD suggested the diagnosis of activated PI3Kδ syndrome (APDS). Genetic analyses identified a heterozygous mutation of the PIK3CD gene (c.1573 G to A p.Glu525Lys). Although prednisolone and cyclosporine therapy has controlled the T-cell LPD, this patient awaits allogeneic hematopoietic cell transplantation to achieve a complete cure of his APDS.

Rapid diagnostic method for the identification of Mycoplasma pneumoniae respiratory tract infection.

Rapid diagnostic tests are useful tools in the early diagnosis of respiratory tract infections (RTIs) caused by a specific pathogens. We investigated the sensitivity and specificity of a rapid and simple antigen test for the detection of Mycoplasma pneumoniae, Ribotest Mycoplasma(®) in adolescent and adult patients with RTIs. In addition, we evaluated the accuracy of clinical and laboratory findings for the early presumptive diagnosis of M. pneumoniae RTI. We compared 55 cases with laboratory-confirmed M. pneumoniae infection using serology, culture, and polymerase chain reaction (PCR) and 346 cases without laboratory-confirmed M. pneumoniae infection. Pneumonia cases were excluded in this study. Among patients with M. pneumoniae infection, the incidences of cough, sore throat, and sputum production were high, with rates of 98%, 61%, and 67%, respectively, but the specificity was low. The prevalence of nasal symptoms was significantly lower in patients with M. pneumoniae infection (9%) than in non-M. pneumoniae infection (70%; p < 0.0001). When PCR was used as the control test, the sensitivity, specificity, and overall agreement rates with Ribotest(®) were 71%, 89%, and 87%, respectively. Clinical symptoms and laboratory data were of limited value in making the diagnosis of M. pneumoniae RTI in adolescent and adult patients. Our results suggested that Ribotest(®) may be helpful in distinguishing M. pneumoniae RTI patients from those without the disease. Physicians should consider the use of Ribotest(®) when patients have a persistent cough without nasal symptoms.

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.

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.

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.

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.