Yoji Nagasaki

High incidence of false-positive Aspergillus galactomannan test in multiple myeloma†

Invasive aspergillosis (IA) remains one of the most significant causes of morbidity and mortality in patients with hematological malignancies undergoing chemotherapy and hematopoietic stem cell transplantation (HSCT), mainly due to the difficulty in its early diagnosis. Monitoring of galactomannan (GM) antigen, an exoantigen of Aspergillus, in the blood by sandwich ELISA is a useful and noninvasive method for early diagnosis of IA. The GM test has a sensitivity of 67-100% with a specificity of 81-99% in neutropenic patients and allogeneic transplant recipients [1-3]. Although it has been widely used as a diagnostic criterion for IA [4,5], one of the major limitations of this assay is false-positivity, particularly in pediatric patients [1], patients with graft-versus-host disease (GVHD) [6,7], and those taking dietary GM [8,9] or fungus-derived antibiotics, such as piperacillin-tazobactam (PIPC/TAZ) [10-12].

Clonal spread in Eastern Asia of ciprofloxacin-resistant Escherichia coli serogroup O25 strains, and associated virulence factors

A significant problem in the field of infectious diseases is the increase in fluoroquinolone (FQ)-resistant Escherichia coli. Although mutation of strains and clonal dissemination are supposed to be the cause of this increase, little is known about the prevalence of this organism. We investigated 219 FQ-resistant E. coli strains in Japan and nine Asian countries by serotyping and genotyping. Seventy-one strains (32.4%) were serogroup O25, which was prevalent in South Korea, China and Japan, especially in the southwest part of Japan. Aerobactin, a virulence factor in uropathogenic and avian pathogenic E. coli, was associated with the presence of FQ-resistant O25 strains of E. coli. Seven of the seventy-one FQ-resistant E. coli O25 had extended-spectrum beta-lactamase genes (six CTX-M-14 and one SHV-12), however, we were unable to find any E. coli O25-ST131 clone that produced CTX-M-15, which was previously reported to have emerged across continents. These data demonstrate that a clonal group of FQ-resistant and virulent E. coli recently became prevalent at least in East Asia and suggest that this might become a public health problem because the strains may acquire resistance to other antimicrobial agents.

Combination therapy with micafungin and amphotericin B for invasive pulmonary aspergillosis in an immunocompromised mouse model

OBJECTIVES Antifungal monotherapy with polyenes, azoles or echinocandins is not always effective for invasive pulmonary aspergillosis (IPA). The main purpose of this study was to evaluate the efficacy of a combination of micafungin and amphotericin B for the primary treatment of IPA in an immunocompromised mouse model. METHODS Female ICR mice were used in all experiments. An immunosuppressive state was induced in mice by an intraperitoneal injection of cyclophosphamide. Mice were intratracheally inoculated with Aspergillus fumigatus conidia, treated with micafungin, amphotericin B or both for 7 days, and were tested for their survival 20 days after the Aspergillus inoculation. Fungal burden in lungs, serum galactomannan index (GMI) and histopathology of lungs, spleen and kidneys were also evaluated. RESULTS Combination therapy with micafungin and amphotericin B gave excellent survival of infected mice compared with monotherapy with micafungin or amphotericin B alone. Combined therapy reduced the fungal burden in the lungs and the serum GM levels compared with monotherapy or untreated controls, resulting in a significant histological improvement with disappearance of fungi in the lungs. CONCLUSIONS These findings suggest that combination therapy with micafungin and amphotericin B is more effective compared with monotherapy with either of them alone for IPA treatment.

Antimicrobial susceptibility and molecular epidemiological analysis of clinical strains of Pseudomonas aeruginosa

Three hundred and seventy-one strains of Pseudomonas aeruginosa were isolated at the laboratory of Kyushu University Hospital in Japan from May 2002 through January 2003. Large proportions of isolated strains were resistant to carbapenems: 37.5% to imipenem, 21.3% to biapenem, and 18.3% to meropenem. A survey of injectable antibacterial agents used in our hospital during the corresponding period showed that carbapenems were most frequently used. Multidrug-resistant P. aeruginosa (MDRP) strains and metallo-β-lactamase producing strains were isolated at frequencies of 1.6% (6 strains) and 0.81% (3 strains), respectively. By molecular epidemiological analysis, neither MDRP nor metallo-β-lactamase producing strains were molecularly related, whereas some imipenem-resistant strains appeared to be epidemic strains, suggesting a possibility that they might spread by nosocomial infection. To control nosocomial infection, it is important to know a trend in drug-resistant P. aeruginosa and to prevent the spread of not only MDRP and metallo-β-lactamase producing strains but also imipenem-resistant P. aeruginosa strains.

A dramatic increase in the positive blood culture rates of Helicobacter cinaedi: the evidence of differential detection abilities between the Bactec and BacT/Alert systems

In our hospital, positive blood culture rates of Helicobacter cinaedi dramatically increased after introducing the Bactec system. A simulated culture model of H. cinaedi bacteremia demonstrated no positive signals using the BacT/Alert system, despite efficient growth in bottles. Clinically suspected H. cinaedi bacteremia should be monitored more closely when using the BacT/Alert system, preferably with subcultivation after 7days of incubation.

Myeloid/natural killer cell blast crisis representing an additional translocation, t(3;7)(q26;q21) in Philadelphia-positive chronic myelogenous leukemia

We encountered a patient in blast crisis (BC) with chronic myelogenous leukemia (CML) who showed immunophenotypic features similar to those previously described in acute myeloid/natural killer (NK) cell precursor leukemia. The blasts were positive for CD7, CD33, CD34, and CD56. Cytogenetic analysis disclosed a Philadelphia chromosome (Ph) and t(3;7)(q26;q21). Molecular analysis did not detect any EVI1/CDK6 chimeric transcript generated by t(3;7)(q26;q21), but did indicate overexpression of EVI1, which occurs frequently in progression to myeloid BC in CML. Three cases of myeloid/NK cell precursor BC in CML have been reported, but this case is the first to present with Ph and EVI1 abnormality. These observations suggested that a myeloid/NK cell precursor might have been involved in the Ph-positive clone and have been a target for blastic transformation of CML, although EVI1 expression is not specific for transformation to BC from myeloid/NK lineage.

Longstanding Remission of Adult Onset Still’s Disease Under Imatinib Therapy in a Patient with Chronic Myelogenous Leukemia

To the Editor: Imatinib mesylate is a potent and selective inhibitor of tyrosine kinases such as Bcr-Abl, platelet-derived growth factor (PDGF) receptor, and c-Kit, and it is widely used to treat chronic myeloid leukemia (CML) and c-Kit-positive gastrointestinal stromal tumors. Imatinib also exerts potent immunomodulatory effects in vitro and in vivo 1. Recent reports described the efficacy of imatinib in treating patients with various autoimmune and inflammatory diseases such as rheumatoid arthritis (RA), systemic scleroderma, pulmonary arterial hypertension, and lupus nephritis2–5. We describe a patient with steroid-resistant adult onset of Stills disease (AOSD), who incidentally developed CML. Treatment with imatinib induced hematological remission of CML as well as improvement of symptoms of AOSD. Immunosuppressants were tapered and discontinued 2 years after the initial imatinib treatment. The patient has maintained remission of AOSD for 5 years under imatinib treatment. In August 2000, a 25-year-old Japanese man was admitted to the Department of GeneralMedicine, Kyushu University Hospital, due to fever of unknown origin. He exhibited symptoms of pharyngitis, arthralgia, typical rash, leukocytosis, high level of C-reactive protein (CRP; 33.0 mg/dl), and hyperferritinemia (19,777 ng/ml). A diagnosis of AOSD was made based on his symptoms and these results. He was treated with prednisolone (PSL; 1 mg/kg daily). … Address reprint requests to Dr. T. Miyamoto, Center for Cellular and Molecular Medicine, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Japan 812-8582. E-mail: toshmiya{at}intmed1.med.kyushu-u.ac.jp

Gastrointestinal Graft-versus-Host Disease Is a Risk Factor for Postengraftment Bloodstream Infection in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Bloodstream infection (BSI) is a well-known cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients. Here, we conducted a retrospective study to assess the morbidity, etiology, risk factors, and outcomes of BSI in the postengraftment period (PE-BSI) after allo-HSCT. Forty-three of 316 patients (13.6%) developed 57 PE-BSI episodes, in which 62 pathogens were isolated: Gram-positive bacteria, gram-negative bacteria, and fungi, respectively, accounted for 54.8%, 35.5%, and 9.7% of the isolates. Multivariate analysis revealed methylprednisolone use for graft-versus-host disease (GVHD) prophylaxis (odds ratio [OR], 6.49; 95% confidence interval [CI], 1.49 to 28.2; P = .013) and acute gastrointestinal GVHD (GI-GVHD) (OR, 8.82; 95% CI, 3.99 to 19.5; P < .0001) as risk factors for developing PE-BSI. This finding suggested that GI-GVHD increases the risk of bacterial translocation and subsequent septicemia. Moreover, among patients with GI-GVHD, insufficient response to corticosteroids, presumably related to an intestinal dysbiosis, significantly correlated with this complication. Patients with PE-BSI presented worse outcome compared with those without (3-year overall survival, 47.0% versus 18.6%; P < .001). Close microbiologic monitoring for BSIs and minimizing intestinal dysbiosis may be crucial to break the vicious cycle between GI-GVHD and bacteremia and to improve transplant outcomes especially in patients who require additional immunosuppressants.

Invasive meningococcal disease due to a non-capsulated Neisseria meningitidis strain in a patient with IgG4-related disease

BackgroundInvasive Meningococcal Disease (IMD) is a rare and critical disease in Japan. Most of these cases are caused by capsulated Neisseria meningitidis strains. Non-capsulated (non-typable) strains are considered relatively low-pathogenic and can colonize in the nasopharynx of healthy children and young adults. As far as could be ascertained, only twelve IMD cases due to non-capsulated strains have been reported in the literature. No clear risk factors could be identified in a literature review (unknown or immunocompetent, seven cases; C6 deficiency, three cases).Case presentationWe report a Japanese male taxi driver with bacteremia and meningitis due to non-capsulated N. meningitidis. He had a fever and shaking chills. Ceftriaxone was administered, and the patient finally recovered. During the clinical course, relative adrenal insufficiency occurred and was treated with hydrocortisone. A hidden co-morbidity, immunoglobulin G4 (IgG4)-related disease, was revealed in the past surgical history (a resection of bilateral orbital tumors), which included symptoms (swelling lachrymal glands and lymph nodes), elevated IgG4, immunoglobulin E, and hypocomplementemia. He recovered finally and no recurrence was observed.ConclusionsOur IMD case is the first reported in Japan, where IMD is not considered pandemic. The patient had a history of IgG4-related disease, although we could not establish a clear relationship between the patient’s IMD and co-morbidity. A collection of further clinical cases might establish the risk factors and characteristics of IMD that could be caused by this neglected pathogen, non-capsulated N. meningitidis.