MicroRNAs in infectious diseases: potential diagnostic biomarkers and therapeutic targets.

MicroRNAs (miRNAs) are conserved, short, non-coding RNAs that play a crucial role in the post-transcriptional regulation of gene expression. They have been implicated in the pathogenesis of cancer and neurological, cardiovascular, and autoimmune diseases. Several recent studies have suggested that miRNAs are key players in regulating the differentiation, maturation, and activation of immune cells, thereby influencing the host immune response to infection. The resultant upregulation or downregulation of miRNAs from infection influences the protein expression of genes responsible for the immune response and can determine the risk of disease progression. Recently, miRNAs have been explored as diagnostic biomarkers and therapeutic targets in various infectious diseases. This review summarizes our current understanding of the role of miRNAs during viral, fungal, bacterial, and parasitic infections from a clinical perspective, including critical functional mechanisms and implications for their potential use as biomarkers and therapeutic targets.

Invasive Aspergillosis in Liver Transplant Recipients in The Current Era.

Invasive aspergillosis (IA) is a rare but fatal disease among liver transplant recipients (LiTRs). We performed a multi-center 1:2 case-control study comparing LiTRs diagnosed with proven/probable IA and controls with no invasive fungal infection. We included 62 IA cases and 124 matched controls. Disseminated infection occurred only in eight cases (13%). 12-week all-cause mortality of IA was 37%. In multivariate analyses, systemic antibiotics usage (adjusted odds ratio [aOR], 4.74; p=0.03) and history of pneumonia (aOR, 48.7; p=0.01) were identified as independent risk factors associated with the occurrence of IA. Moreover, reoperation (aOR, 5.99; p=0.01), systemic antibiotics usage (aOR, 5.03; p=0.04), and anti-mold prophylaxis (aOR, 11.9; p=0.02) were identified as independent risk factors associated with the occurrence of early IA. Among IA cases, Aspergillus colonization (adjusted hazard ration [aHR], 86.9; p<0.001), ICU stay (aHR, 3.67; p=0.02), disseminated IA (aHR, 8.98; p<0.001), and dialysis (aHR, 2.93; p=0.001) were identified as independent risk factors associated with 12-week all-cause mortality; while recent receipt of tacrolimus (aHR, 0.11; p=0.001) was protective. Mortality among LiTRs with IA remains high in the current era. The identified risk factors and protective factors may be useful for establishing robust targeted anti-mold prophylactic and appropriate treatment strategies against IA.

Predictive scoring system for distinguishing Stenotrophomonas maltophilia bacteremia from Pseudomonas aeruginosa bacteremia in patients with hematological malignancies.

Difficulties in immediately distinguishing Stenotrophomonas maltophilia (SM) bacteremia from Pseudomonas aeruginosa (PA) bacteremia in the clinical setting can lead to treatment delay. We aimed to develop a scoring system to immediately distinguish SM bacteremia from PA bacteremia using clinical indicators. We enrolled cases of SM and PA bacteremia in adult patients with hematological malignancies between January 2011 and June 2018. The patients were randomized into derivation and validation cohorts (2:1), and a clinical prediction tool for SM bacteremia was developed and verified. In total, 88 SM and 85 PA bacteremia cases were identified. In the derivation cohort, the following independent predictors of SM bacteremia were identified: no evidence of PA colonization, antipseudomonal ß-lactam breakthrough bacteremia, and central venous catheter insertion. We scored each of the three predictors according to their regression coefficient (2, 2, and 1, respectively). Receiver operating characteristic curve analysis confirmed the score's predictive performance, with an area under the curve of 0.805. The combined sensitivity and specificity (0.655 and 0.821) was highest with a cut-off value of 4 points. Positive and negative predictive values were 79.2% (19/24) and 69.7% (23/33), respectively. This novel predictive scoring system is potentially useful for distinguishing SM bacteremia from PA bacteremia, which would facilitate immediate administration of appropriate antimicrobial therapy.

Clinical and Microbiological Characteristics of Proven Invasive Aspergillosis Due to Rare/Cryptic Species in Allogeneic Hematopoietic Stem Cell Transplant Recipients.

There are few reports on the clinical course of proven invasive aspergillosis (IA) due to rare/cryptic species in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. We retrospectively reviewed the electronic medical records of patients who underwent allo-HSCT between January 2012 and December 2018. Of 934 allo-HSCT recipients, 10 were diagnosed with proven IA and 61 were diagnosed with probable IA. DNA sequencing was performed in cases of proven IA, and Aspergillus could be identified to the species level in 8 of the 10 cases. Three were due to A. fumigatus, and 5 were due to rare/cryptic Aspergillus species, namely, A. turcosus, A. felis, A. viridinutans, A. nidulans, and A. calidoustus. In these 8 patients, no patients with IA due to A. fumigatus died, whereas 3 of the 5 with IA due to rare/cryptic species died within 12 weeks. The 2 surviving cases of IA due to rare/cryptic species were treated with surgical resection and antifungal treatment. Susceptibility testing for cryptic species in 4 cases showed an amphotericin B MIC > 1 mg/L in 3 cases, itraconazole MIC > 1 mg/L in 2 cases, and voriconazole MIC > 1 mg/L in 2 cases. In conclusion, more than half of the causative pathogens of proven IA were rare/cryptic species, so it is important to accurately identify the Aspergillus species. In addition, surgical treatment might be an important option in cases of proven IA, given the possibility that the causative organisms are azole-resistant A. fumigatus or rare/cryptic species.

Factors Associated with Breakthrough Fungemia Caused by Candida, Trichosporon, or Fusarium Species in Patients with Hematological Disorders.

Limited data are available on breakthrough fungemia, defined as fungemia that develops on administration of antifungal agents, in patients with hematological disorders. We reviewed the medical and microbiological records of adult patients with hematological diseases who had breakthrough fungemia between January 2008 and July 2019 at Toranomon Hospital and Toranomon Hospital Kajigaya in Japan. A total of 121 cases of breakthrough fungemia were identified. Of the 121 involved patients, 83, 11, 5, and 22 were receiving micafungin, voriconazole, itraconazole, and liposomal amphotericin B, respectively, when the breakthrough occurred. Of the 121 causative breakthrough fungal strains, 96 were Candida species, and the rest were 13 cases of Trichosporon species, 7 of Fusarium species, 2 of Rhodotorula mucilaginosa, and 1 each of Cryptococcus neoformans, Exophiala dermatitidis, and Magnusiomyces capitatus. The crude 14-day mortality rate of breakthrough fungemia was 36%. Significant independent factors associated with the crude 14-day mortality rate were age of ≥60 years (P = 0.011), chronic renal failure (P = 0.0087), septic shock (P < 0.0001), steroid administration (P = 0.0085), and liposomal amphotericin B breakthrough fungemia (P = 0.0011). An absolute neutrophil count of >500/µL was significantly more common in candidemia in the multivariate analysis (P = 0.0065), neutropenia and nonallogeneic hematopoietic stem cell transplants were significantly more common in Trichosporon fungemia (P = 0.036 and P = 0.033, respectively), and voriconazole breakthrough fungemia and neutropenia were significantly more common in Fusarium fungemia (P = 0.016 and P = 0.016, respectively). The epidemiological and clinical characteristics of breakthrough fungemia of patients with hematological disorders were demonstrated. Some useful factors to predict candidemia, Trichosporon fungemia, and Fusarium fungemia were identified.

Clinical characteristics and drug susceptibility patterns of Corynebacterium species in bacteremic patients with hematological disorders.

The aim of this study was to clarify the clinical and microbiological characteristics of Corynebacterium bacteremia in hematological patients. We retrospectively reviewed the medical records of patients with Corynebacterium bacteremia from April 2013 to June 2018. The causative Corynebacterium species were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Drug susceptibility tests were performed using the broth microdilution method recommended by the Clinical and Laboratory Standards Institute. In total, 147 cases of Corynebacterium bacteremia were identified during the study period. Corynebacterium striatum was the most frequent pathogen. Catheter-related bloodstream infection was diagnosed in 19.7% of all patients, and moderate/severe oral or severe gastrointestinal mucosal impairment was detected in 19.7%. Polymicrobial infection was found in about 20% of cases, with Enterococcus faecium being the most frequent isolate. The overall 30-day mortality was 34.7% (51/147). Multivariate analysis showed that E. faecium co-infection (odds ratio (OR) 9.3; 95% confidence interval (CI) 2.1-40), systemic corticosteroids (OR 3.6; 95% CI 1.4-8.9), other immunosuppressive drugs (OR 0.32; 95% CI 0.13-0.76), and a Pitt bacteremia score ≥4 (OR 12; 95% CI 3.9-40) were significant risk factors for overall 30-day mortality. The drug susceptibility rates for beta-lactam antimicrobial agents were quite low. All isolates were susceptible to glycopeptides and linezolid. However, some C. striatum isolates were resistant to daptomycin. Corynebacterium bacteremia can occur in the presence of several types of mucosal impairment. Our drug susceptibility data indicate that Corynebacterium bacteremia in hematological patients could be treated by glycopeptides or linezolid.

Characteristics of gram-negative bacteremia during febrile neutropenia among allogeneic hematopoietic stem cell transplant recipients on levofloxacin prophylaxis.

The aim of this study is to clarify the characteristics of gram-negative bacteremia (GNB), including extended-spectrum ß-lactamase (ESBL)-producing pathogens, among allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients on levofloxacin (LVFX) prophylaxis. A retrospective analysis on GNB at the first episode of febrile neutropenia (FN) was conducted among allo-HSCT recipients (age ≥ 20 years) on 500 mg/day of oral LVFX prophylaxis. Epidemiological and microbiological features of GNB were investigated and compared between the inappropriate and appropriate empiric therapy groups. In total, FN occurred in 414 allo-HSCT cases, and bacteremia at the first episode of FN occurred in 169 cases. Overall, 29 GNB cases were documented, and the causative organisms identified were Escherichia coli in 21 cases (including 10 ESBLs), Klebsiella pneumoniae in 2, Pseudomonas aeruginosa in 2, and other in 4. The crude 30-day mortality rate was not significantly different among cases of GNB (6.9%), gram-positive bacteremia (GPB) (7.1%), or non-bacteremia (5.4%; P = 0.78). Cefepime (CFPM) was administered in all cases in the inappropriate empiric therapy group, and all causative organisms were ESBL-producing E. coli (ESBL-EC). All patients in the inappropriate empiric therapy group had a low Pitt bacteremia score (≤ 2). Thirty-day mortality did not differ significantly between the inappropriate and appropriate empiric therapy groups (1/10 vs. 1/15, P = 0.61). In conclusion, GNB was not a significant cause of death. In LVFX breakthrough ESBL-EC bacteremia among allo-HSCT recipients, the administration of CFPM as empiric therapy did not lead to significantly poor prognosis. Empiric CFPM administration might be an acceptable strategy.

Safety of bronchoscopy in patients with malignant hematologic disorders.

BACKGROUND: Factors affecting the safety of bronchoscopy in patients with malignant hematologic disorders have not been well described. We evaluated the safety of bronchoscopy and describe factors affecting its complication rate in such patients. METHODS: Between January 2009 and December 2018, 316 bronchoscopies in 282 patients with malignant hematologic disorders and pulmonary infiltrates were performed at our institution. The bronchoscopic procedure used and its complications were evaluated. RESULTS: The most common underlying disease was acute myeloid leukemia (134/282 patients, 47.5%). Platelet transfusion was performed the day before or the day of bronchoscopy in 42.4%, supplemental oxygen was administered before the procedure in 23.1%, and midazolam was used in 74.4%. Thirty-five bronchoscopies (11.1%) were complicated by hemoptysis and 7 patients developed pneumothorax, 4 of whom required thoracic drainage. Two patients (0.6%) were intubated within 48 h of the procedure and prolonged oxygen desaturation (> 48 h) occurred in 3.8%. Multivariate analysis showed that only use of midazolam significantly reduced the risk of prolonged oxygen desaturation (hazard ratio 0.28, 95% confidence interval 0.09-0.85, p = 0.03). Transbronchial lung biopsy significantly increased the risk of hemoptysis (hazard ratio 10.40, 95% confidence interval 4.18-25.90, p = 0.00), while use of midazolam significantly reduced the risk (hazard ratio 0.31, 95% confidence interval 0.14-0.73, p = 0.01). CONCLUSIONS: Bronchoscopy is relatively safe in patients with malignant hematologic disorders. Caution and judicious use of sedatives may improve the patient's procedural tolerance and lower complications.

Cryptococcal meningitis following umbilical cord blood transplantation, association between the occurrence of cryptococcal infection and tacrolimus discontinuation among allogeneic hematopoietic stem cell recipients.

Few cases of cryptococcal infection following umbilical cord blood transplantation (UCBT) have been reported. We report a case, where cryptococcal infection occurred soon after rapidly reducing the dose of tacrolimus in a UCBT recipient who received micafungin prophylaxis during the early phase of transplantation. The etiology of cryptococcal infection following allogeneic hematopoietic stem cell transplantation (allo-HSCT), including UCBT, might be associated with rapid dose-reduction of calcineurin inhibitors, such as tacrolimus during early phase of allo-HSCT. To our knowledge, this is the first English-language report to describe in detail a case of cryptococcal meningitis with fungemia during early phase of UCBT.

Risk Factors for Recurrent Helicobacter cinaedi Bacteremia and the Efficacy of Selective Digestive Decontamination With Kanamycin to Prevent Recurrence.

Background: Previous studies suggest that Helicobacter cinaedi can cause recurrent bacteremia. In this study, we elucidated the risk factors for recurrent H. cinaedi bacteremia and explored the efficacy of selective digestive decontamination (SDD) as a preventive measure. Methods: We retrospectively reviewed the medical records of patients with H. cinaedi bacteremia between March 2009 and December 2016 at 2 Japanese hospitals. Results: We identified 168 patients with H. cinaedi bacteremia. Bacteremia recurred in 34 patients. The 100-day cumulative incidence rate of recurrent bacteremia was 18.7%. In univariate analysis of factors associated with recurrent bacteremia, anticancer chemotherapy (hazard ratio [HR], 3.75; 95% confidence interval [CI], 1.86-7.58; P < .001), systemic steroids (HR, 3.79; 95% CI, 1.70-8.45; P = .0011), and hematological malignancy (HR, 3.18; 95% CI, 1.64-6.19; P < .001) were detected. Multivariate analysis indicated that anticancer chemotherapy (HR, 2.47; 95% CI, 1.19-5.12; P = .015) and systemic steroids (HR, 2.40; 95% CI, 1.03-5.61; P = .044) were the independent risk factors. Of the 168 patients, 47 received SDD. According to Gray's test, SDD might have reduced the rate of recurrence but this was not statistically significant (HR, 0.46; 95% CI, 0.18-1.18; P = .11). However, in a proportional hazard modeling analysis, SDD reduced the rate of recurrence (HR, 0.36; 95% CI, 0.13-1.00; P = .050). Conclusions: The 100-day cumulative incidence of recurrent H. cinaedi bacteremia was 18.7%. Anticancer chemotherapy and systemic steroids were independent risk factors for recurrent bacteremia. SDD is a potential strategy for reducing the recurrence.

Clinical and Microbiological Characteristics of Candida guilliermondii and Candida fermentati.

A total of 46 clinical isolates of Candida guilliermondii and Candida famata were reidentified genetically, resulting in 27 C. guilliermondii and 12 Candida fermentati strains. The majority of C. guilliermondii strains, but not C. fermentati strains, were isolated from blood cultures. C. fermentati was more sensitive to antifungals, hydrogen peroxide, and killing by murine macrophages than was C. guilliermondii The C. guilliermondii isolates were echinocandin susceptible in vitro but resistant to micafungin in a murine model of invasive candidiasis.

Micafungin Breakthrough Fungemia in Patients with Hematological Disorders.

Limited data are available on micafungin breakthrough fungemia (MBF), fungemia that develops on administration of micafungin, in patients with hematological disorders. We reviewed medical and microbiological records of patients with hematological disorders who developed MBF between January 2008 and June 2015. A total of 39 patients with MBF were identified, and Candida (30 strains) and non-Candida (9 strains) fungal species were recognized as causative strains. Among 35 stored strains, Candida parapsilosis (14 strains), Trichosporon asahii (7 strains), Candida glabrata (5 strains), and other fungal species (9 strains) were identified by sequencing. Neutropenia was identified as an independent predictor of non-Candida fungemia (P = 0.023). T. asahii was the most common causative strain (7/19) during neutropenia. The 14-day crude mortality rate of patients treated with early micafungin change (EMC) to other antifungal agents was lower than that of the patients not treated with EMC (14% versus 43%, P = 0.044). Most of the stored causative Candida strains were susceptible (80%) or showed wild-type susceptibility (72%) to micafungin. The MICs of voriconazole for T. asahii were low (range, 0.015 to 0.12 µg/ml), whereas the MICs of amphotericin B for T. asahii were high (range, 2 to 4 µg/ml). MBF caused by non-Candida fungus should be considered, especially in patients with neutropenia. EMC could improve early mortality. Based on epidemiology and drug susceptibility profiling, empirical voriconazole-containing therapy might be suitable for treating MBF during neutropenia to cover for T. asahii.

First evidence of bacterial translocation from the intestinal tract as a route of Helicobacter cinaedi bacteremia.

BACKGROUND: The route of Helicobacter cinaedi bacteremia has not yet been clarified. Although bacterial translocation from the intestinal tract into the circulation has been suggested, it has not been demonstrated thus far. The objective of this study was to investigate the port of entry of this bacterium. MATERIAL AND METHODS: We conducted a retrospective study on patients with H. cinaedi bacteremia between March 2009 and May 2013. Records of patients in whom H. cinaedi was detected in both blood and stool cultures were extracted. H. cinaedi was identified using gyrB-targeted PCR. Pulse-field gel electrophoresis was used to investigate the consistency of the genotypes. RESULTS: Seventy-one patients were diagnosed with H. cinaedi bacteremia during the study period. H. cinaedi was detected in both blood and stool samples of 21 patients. Pulse-field gel electrophoresis was used to investigate the consistency of the genotypes in 18 evaluable strains (from 9 patients). The pulse-field gel electrophoresis patterns of the stool- and blood-derived strains of H. cinaedi were consistent among all 9 patients. Most of the 9 patients analyzed were immunocompromised and being treated with anticancer drugs or steroids, which suggests reduced intestinal immunity. CONCLUSIONS: This is the first study to demonstrate that bacterial translocation from the intestinal tract could represent one route of H. cinaedi bacteremia.

Clinical and Microbiological Characteristics of Breakthrough Candidemia in Allogeneic Hematopoietic Stem Cell Transplant Recipients in a Japanese Hospital.

Few data on breakthrough candidemia (BC), defined as candidemia that develops on administration of antifungal agents (AFAs), in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients are available. The medical and microbiological records of recipients of an allo-HSCT obtained between December 2008 and December 2014 were reviewed. Of 768 allo-HSCT cases, 26 developed BC. Among the 26 causative strains, 22 strains were stored and identified by sequencing. The following species were isolated: Candida parapsilosis (9 strains), C. glabrata (4 strains), C. guilliermondii (3 strains), and other Candida species (6 strains). The AFAs being used when BC developed were micafungin (17 cases), liposomal amphotericin B (5 cases), itraconazole (2 cases), and voriconazole (2 cases). All 17 cases who developed BC during micafungin administration were administered 150 mg/day of micafungin. The susceptibilities of the causative Candida species to the administered AFAs when breakthrough occurred ranged from susceptible to resistant. Especially, 85% of the Candida species that caused BC during micafungin administration were susceptible to micafungin. Additionally, 75% of the strains were wild type for susceptibility to the administered AFAs when breakthrough occurred. Systemic steroid administration and a longer severe neutropenic phase (≥5 days) were independent risk factors for BC (P = 0.016 and P = 0.015, respectively). BC developed in allo-HSCT recipients even when they received a sufficient dose of AFA, including micafungin, to which the causative Candida species were susceptible and/or had wild-type susceptibility in vitro Systemic steroid administration and a longer severe neutropenic phase were host-based factors associated with BC.

Successful Treatment of Pulmonary Mucormycosis Caused by Cunninghamella bertholletiae with High-Dose Liposomal Amphotericin B (10 mg/kg/day) Followed by a Lobectomy in Cord Blood Transplant Recipients.

Infection caused by Cunninghamella bertholletiae carries one of the highest mortality rates among mucormycosis, and there are no reported cases that survived from the infection in allogeneic hematopoietic stem cell transplantation recipients occurring before neutrophil engraftment. Here, we present two cases of pulmonary mucormycosis caused by C. bertholletiae occurring before neutrophil engraftment after cord blood transplantation. Both were successfully treated with high-dose liposomal amphotericin B (10 mg/kg/day) combined with micafungin, which was then followed by neutrophil recovery, reduction in immunosuppressive agents, and a subsequent lobectomy. The intensive antifungal therapy immediately administered upon suspicion of mucormycosis greatly suppressed the infection in its early stage and was well tolerated despite its prolonged administration and simultaneous use of nephrotoxic agents after transplantation. Although the synergic effect of micafungin remains unclear, these cases highlight the importance of prompt administration of high-dose lipid polyene when suspecting mucormycosis in highly immunocompromised patients, which enables subsequent diagnostic and therapeutic interventions, resulting in a favorable outcome.

[Investigation of the Pathophysiology and Diagnostic Methods Through a Case of Acute HIV Infection in which the Western Blot Method Remained Negative Over the Long Term and the 4th Generation Screening Assay Became Negative for a Certain Period of Time after Initiating Antiretroviral Therapy].

Confirmatory tests using Western blot (WB) and HIV-1 nucleic acid testing (HIV-1 RNA) following a positive screening test are required for the diagnosis of HIV-1 infection according to the current Japanese guidelines for HIV-1/2 diagnosis. We report herein on a rare case in a patient who remained negative for WB over 10 months in spite of being positive by fourth-generation immunoassays (4thGIA) and who subsequently seroreverted by 4thGIA for three months after initiating antiretroviral therapy. Case: A man in his early twenties previously visited a hospital because of fever in October 2012. Laboratory data revealed leukocytopenia, thrombocytopenia and increased serum ferritin, suggesting hemophagocytic syndrome (HPS). During that visit, he tested positive for a 4thGIA, but negative for HIV-1 WB and his result of HIV-1 RNA result was detected invalid because of the presence of some inhibitory material in his RNA preparation. Thereafter, he was diagnosed as having cytomegalovirus-associated HPS treatment was for which initiated. In January 2013, he developed Pneumocystis jirovecii pneumonia, and his HIV-1 RNA viral load was 7.7 × 105 copies/mL in February 2013. Acute HIV infection was suspected, because the HIV-1 WB remained negative. He was started on antiretroviral therapy in April 2013. His 4thGIA was converted to negative in May 2013 and was reconverted to positive in August 2013. HIV-1 WB, however, continued to be indeterminant until February 2014, in which it turned positive for the first time according to the CDC criteria. Methods and Results: The genetic analyses of HIV-1 were done on the gag, env, nef and pol region of the HIV-1 gene from the patient. There was no clear element to delay antibody production on the virus side. Preserved specimens of the patient were measured with eight kinds of HIV screening assay. It was thought that the fourth generation assay was positive only by the presence of the antigen until March 2013 because the antibody had not been detected. Discussion: We encountered a case of acute HIV infection in which the WB result was negative for 10 months after the first positive response of the 4thGIA. The 4thGIA is essential for the early diagnosis and early treatment of HIV infection; therefore, the 4thGIA should be strictly recommended to avoid the use of older generations of immunoassay in the diagnostic guidelines. The role of the WB test should be examined closely from various aspects for use as a confirmatory test under recent laboratory situations in which highly sensitive and specific methods, e.g. the 4th GIA, have become available. In addition, unnecessary confusion due to the diversities of antibody formation should be avoided. The antibody detection tests for HIV are still necessary and indispensable for the confirmation of the disease or the diagnosis of the acute infection stage. Therefore development of a newer antibody measuring method which could achieve an easier operation and should have a higher sensitivity and specificity for HIV confirmation is strongly expected.

Breakthrough viridans streptococcal bacteremia in allogeneic hematopoietic stem cell transplant recipients receiving levofloxacin prophylaxis in a Japanese hospital.

BACKGROUND: Breakthrough viridans streptococcal bacteremia (VSB) in patients with hematological malignancy receiving levofloxacin prophylaxis is a major blood stream infection (BSI) occurring during febrile neutropenia. However, clinical data focused on VSB in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients are lacking. METHODS: The medical records of allo-HSCT recipients who received oral levofloxacin prophylaxis between January 2011 and August 2013 at Toranomon Hospital were reviewed to evaluate breakthrough VSB. Stored viridans streptococcal (VGS) species were identified by using sodA gene sequencing, and were assessed for drug susceptibility. RESULTS: Among the 184 allo-HSCT recipients on levofloxacin prophylaxis, 28 (15.2 %) experienced breakthrough VSB. All of the 28 recipients with VSB were treated with a cefepime-based or piperacillin/tazobactam-based regimen. The susceptibility rates of the VGS strains for levofloxacin, cefepime, piperacillin/tazobactam, meropenem, and vancomycin were 0 %, 95 %, 100 %, 100 %, and 100 %, respectively. Both the MIC50 (minimum inhibitory concentration) and the MIC90 of ceftazidim (0.5 µg/mL and 2 µg/mL, respectively) were higher than the MIC90 of all the other anti-pseudomonal beta-lactams (APBLs). Only 1 VGS strain had a penicillin MIC ≥ 2 µg/mL by the Etest (3.6 %). There were no cases with acute respiratory distress syndrome (ARDS) that was associated with VSB, although the rate of viridans group streptococcal shock syndrome was high (26 %). The crude 30-day mortality rate in the VSB group (10.7 %) did not differ significantly from that in the BSI without VSB group (9.3 %) or non-BSI group (7.0 %) (P = 0.77). Also, VSB was not a risk factor for all-cause mortality up to 60 days following allo-HSCT (P = 0.43). CONCLUSIONS: APBL with increased anti-VGS activity (APBL-VA) monotherapy would typically be optimal for treating the VGS strains in this setting. Indication of adding an empiric anti-gram-positive agent to APBL-VA for treating VSB should depend on local factors, such as the susceptibility results. In addition, breakthrough VSB is probably not a major cause of death in allo-HSCT settings, where beta-lactam non-susceptible VGS and the ARDS are rare.

Clinical characteristics of bacteremia caused by Helicobacter cinaedi and time required for blood cultures to become positive.

The aim of this study was to clarify the clinical characteristics of patients with Helicobacter cinaedi bacteremia and the time required for blood cultures to become positive. The medical records of all patients with H. cinaedi bacteremia at Toranomon Hospital and Toranomon Hospital Kajigaya between March 2009 and March 2013 were retrospectively reviewed. Sixty-three patients, 34 men and 29 women with a median age of 67 years (range, 37 to 88 years), were diagnosed with H. cinaedi bacteremia. A total of 51,272 sets of blood cultures were obtained during the study period, of which 5,769 sets of blood cultures were positive for some organism and 126 sets were H. cinaedi positive. The time required for blood cultures to become positive for H. cinaedi was ≤5 days in 69 sets (55%) and >5 days in 57 sets (45%). Most patients had an underlying disease, including chronic kidney disease (21 cases), solid tumor (19 cases), hematological malignancy (13 cases), diabetes mellitus (8 cases), chronic liver disease (6 cases), and postorthopedic surgery (3 cases). Only 1 patient had no apparent underlying disease. The clinical symptoms included cellulitis in 24 cases, colitis in 7 cases, and fever only in 27 cases, including 7 cases of febrile neutropenia. The 30-day mortality rate of H. cinaedi bacteremia was 6.3%. In conclusion, most cases of H. cinaedi bacteremia occurred in immunocompromised patients. We might have overlooked nearly half of the H. cinaedi bacteremia cases if the duration of monitored blood culture samples had been within 5 days. Therefore, when clinicians suspect H. cinaedi bacteremia, the observation period for blood cultures should be extended.

Serum (1,3)-beta-D-glucan is an inefficient marker of breakthrough candidemia.

The aim of this study was to evaluate the usefulness of serum (1,3)-beta-D-glucan (BDG) for earlier detection of breakthrough candidemia. We reviewed the medical records of patients with candidemia from January 2008 to March 2013. Serum BDG was measured by Wako turbidimetric assay. During the study period, a total of 147 cases of candidemia were identified, and 31 patients met the criteria for breakthrough candidemia. Serum BDG levels were measured in 25 patients with breakthrough candidemia and 67 patients with nonbreakthrough candidemia. Almost all of the patients with breakthrough candidemia had hematological malignancies. More candidemia were caused by non-C. albicans Candida in the breakthrough group than in the nonbreakthrough group (92.0% vs. 61.8%, p = .005). The median BDG value was significantly lower in breakthrough episodes than in non-breakthrough episodes (18.5 pg/ml vs. 90.4 pg/ml, p = .01). Moreover, BDG values under the cutoff was significantly higher in patients with breakthrough candidemia than in those with nonbreakthrough candidemia (44% vs. 19%, p = .03). In summary, BDG alone was insufficient to detect breakthrough candidemia, and candidemia could occur in patients being treated with antifungal agents, even when the BDG value was under the cutoff value.

Aeromonas caviae is the most frequent pathogen amongst cases of Aeromonas bacteremia in Japan.

BACKGROUND: Aeromonas species can cause various infections including bacteremia, gastroenteritis, cholangitis, and wound infections. To date, most studies on Aeromonas species have been reported from countries other than Japan. The aim of this study, therefore, was to evaluate Aeromonas bacteremia in Japan. METHODS: We reviewed the medical records of patients with Aeromonas bacteremia from January 1994 to December 2010 in Toranomon Hospital, Tokyo, and Toranomon Hospital Kajigaya, Kanagawa, Japan. RESULTS: Thirty-six cases of Aeromonas bacteremia were identified. Of these 36 strains, 18 were Aeromonas caviae, 13 were Aeromonas hydrophila, and 5 were Aeromonas veronii biovar sobria. The underlying diseases were solid tumor (21 cases), chronic hepatic disease (13 cases), diabetes mellitus (9 cases), hematological malignancies (4 cases), autosomal dominant polycystic kidney disease (2 cases), and aplastic anemia (2 cases). Patients with a solid tumor more frequently presented with A. caviae bacteremia than non-A. caviae bacteremia (14/18 vs 7/18; p = 0.041). Additionally, 16 of the 36 episodes were polymicrobial, and of these, 12 had stenosis or stasis of the bile duct or pancreatic duct (75%). The overall 30-day mortality was 19%. CONCLUSIONS: To the best of our knowledge, this is the first report to identify A. caviae as the most frequent causative pathogen of Aeromonas bacteremia in Japan. Additionally, compared with previous studies, most patients in our study had solid tumors. These findings suggest that the characteristics of Aeromonas bacteremia vary among study populations.