Aureobasidium melanigenum catheter-related bloodstream infection: a case report.

BACKGROUND: Aureobasidium melanigenum is a ubiquitous dematiaceous fungus that rarely causes invasive human infections. Here, we present a case of Aureobasidium melanigenum bloodstream infection in a 20-year-old man with long-term catheter use. CASE PRESENTATION: A 20-year-old man receiving home care with severe disabilities due to cerebral palsy and short bowel syndrome, resulting in long-term central venous catheter use, was referred to our hospital with a fever. After the detection of yeast-like cells in blood cultures on day 3, antifungal therapy was initiated. Two identification tests performed at a clinical microbiological laboratory showed different identification results: Aureobasidium pullulans from matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and Cryptococcus albidus from a VITEK2 system. Therefore, we changed the antifungal drug to liposomal amphotericin B. The fungus was identified as A. melanigenum by DNA sequence-based analysis. The patient recovered with antifungal therapy and long-term catheter removal. CONCLUSION: It is difficult to correctly identify A. melanigenum by routine microbiological testing. Clinicians must pay attention to the process of identification of yeast-like cells and retain A. melanigenum in cases of refractory fungal infection.

Protothecosis in the mucosa of the pharynx mimicking pharyngeal cancer in an immunocompetent individual: a case report.

BACKGROUND: Protothecosis is a rare infection in humans and animals caused by the achlorophyllic algae Prototheca species. More than half of the protothecosis cases are cutaneous infections, and most cases are observed in immunocompromised individuals. CASE PRESENTATION: We report a case of Prototheca wickerhamii infection in the mucosa of the pharynx in a 53-year-old immunocompetent woman with an incidentally found mass lesion at the left tongue base. Histopathological findings of the mass lesion suggested cryptococcosis, but P. wickerhamii was identified from the oropharynx scrape culture based on DNA sequencing. After surgical resection, fosfluconazole treatment was initiated, and subsequently, treatment was switched to topical amphotericin B. The residual mass lesion did not deteriorate during the 4-month antifungal treatment and 1-year observational period. CONCLUSIONS: Prototheca species can be easily misdiagnosed as yeasts because of their morphological and pathological similarities. Prototheca, in addition to Cryptococcus should be considered if slow-growing, large Gram-positive organisms are encountered. Lactophenol cotton blue staining of the colony helps distinguish these organisms. Further study is needed to determine the appropriate treatment according to the infection focus.

Successful treatment of pneumonia caused by multidrug-resistant Pseudomonas aeruginosa after allogeneic hematopoietic stem cell transplantation with colistin and amikacin inhalation therapy.

Pseudomonas aeruginosa is a Gram-negative bacillus that often causes severe infections during immunosuppression in patients with hematologic malignancies. P. aeruginosa can easily acquire drug resistance, and often develops into multidrug-resistant P. aeruginosa (MDRP). Although many antibiotics are used in combination to treat MDRP infections, colistin and amikacin are less likely to be transferred to the lungs, and inhalation therapy may be used. Herein, we report a Case of pneumonia caused by MDRP after allogeneic hematopoietic stem cell transplantation (HSCT) treated with inhaled colistin and amikacin. This 61-year-old female patient was diagnosed with myelodysplastic syndromes and underwent allogeneic HSCT from an 8/8 HLA-matched unrelated donor after reduced-intensity conditioning. On the day of the stem cell infusion, the patient's sputum culture was found to be positive for MDRP. The patient subsequently developed bacteremia, pneumonia, and lung abscess caused by MDRP, and we administered multidrug antibiotic therapy including colistin and amikacin inhalation therapy. The patient's blood cultures were subsequently turned negative, and the lung abscess disappeared. To our knowledge, this is the first case of MDRP pneumonia after HSCT in which colistin and amikacin inhalation therapy was effective.

Neisseria meningitidis serogroup W135 in a traveler visiting Japan from Argentina, 2019.

Invasive meningococcal disease (IMD) can occur in travelers returning from mass-gathering events or endemic regions. We present a 60-year-old Argentine traveler to Tokyo who developed IMD by Neisseria meningitidis Serogroup W135 during her stay in Japan. N. meningitidis serogroup W135 infection has become common in Argentina, whereas IMD less commonly occurs in Japan. Considering the prevalence, the patient most likely acquired the infection in Argentina, and it developed in Japan. Air travel enables passengers to reach the four corners of the world within a few days. IMD should be considered in travelers due to its potential to induce rapid clinical deterioration and transmission.

Human abdominal abscess caused by Necropsobacter rosorum and tips for its identification: A case report.

Necropsobacter rosorum is a gram-negative facultative anaerobe, which was reclassified from the family Pasteurellaceae in 2011. It has been detected in the gastrointestinal and respiratory tracts of mammals; however, reports of infection in humans are scarce. We report a case of an abdominal abscess in which N. rosorum was detected; it was successfully treated with drainage and antimicrobial therapy. Routine laboratory testing such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and an identification system using biochemical phenotypes could not identify N. rosorum. Instead, it was misidentified as other Pasteurellaceae species, including Aggregatibacter spp. or Pasteurella spp. Sequencing of 16S rRNA was required to identify N. rosorum. We suggest the application of simple methods, such as indole production, oxidase, and catalase tests, to differentiate N. rosorum from genetically similar species.

Prevalence and clinical characteristics of patients with biologically false-positive reactions with serological syphilis testing in contemporary practice: 10-year experience at a tertiary academic hospital.

OBJECTIVES: Biologically false positive (BFP) reactions are well described in early literature. However, only a few recent reports described the incidence and clinical characteristics of patients with BFP reactions. We reviewed the serological test results of patients tested for syphilis in our hospital in the past decade and described the clinical characteristics of patients with BFP reactions. METHODS: This is a retrospective study of patients tested for syphilis in a tertiary academic hospital. All serological results were retrieved from the clinical laboratory database. We calculated the incidence of BFP reactions. Clinical characteristics and laboratory data of patients with BFP reactions were reviewed manually. RESULTS: Among 94 462 subjects, 588 patients had BFP reactions (0.62%). Most BFP reactions were observed in patients aged over 60 years, with a history of malignancy and autoimmune diseases. Eighty-five per cent of patients had low rapid plasma reagin (RPR) titre (≤1:4), but two patients had extremely high RPR titre (≥1:256). BFP reactions were more likely to persist beyond 6 months among patients with RPR titre of ≥1:8. There was no statistically significant correlation between RPR titre and total protein albumin gap, surrogate of immunoglobulin levels among patients with BFP reactions. CONCLUSION: There was a low incidence of BFP reactions in the last decade. A minority of BFP reactions had high non-treponemal antibody titre and persisted longer than 6 months. In the era of re-emergence of syphilis, this information could help clinicians interpret the results of well-established diagnostic tests for syphilis.

Change in hepatitis C virus positivity among needle-stick injury source patients: a 10-year experience in a Japanese tertiary hospital.

BACKGROUND: As a blood-borne pathogen, hepatitis C virus (HCV) has long been a major threat associated with needle-stick injuries (NSIs) mainly because no vaccine is available for HCV. Following an NSI, we usually test the source patient for HCV antibody (HCV-Ab). Since HCV-Ab positivity does not necessarily indicate current infection, HCV RNA is further examined in patients positive for HCV-Ab. Direct-acting antivirals (DAAs) have enabled us to treat most HCV-infected patients; therefore, we speculate that the rate of HCV RNA positivity among HCV-Ab-positive patients decreased after the emergence of DAAs. This cross-sectional study was performed to investigate the change in the actual HCV RNA positivity rate in source patients before and after the interferon (IFN)-free DAA era. METHODS: This was a cross-sectional study of NSI source patients at a tertiary academic hospital in Japan from 2009 to 2019. IFN-free DAA regimens were first introduced in Japan in 2014. Accordingly, we compared HCV status of NSI source patients that occurred between 2009 and 2014 (the era before IFN-free DAAs) with those that occurred between 2015 and 2019 (the era of IFN-free DAAs) in a tertiary care hospital in Japan. RESULTS: In total, 1435 NSIs occurred, and 150 HCV-Ab-positive patients were analyzed. The proportion of HCV RNA-positive patients significantly changed from 2009 through 2019 (p = 0.005, Cochran-Armitage test). Between 2009 and 2014, 102 source patients were HCV-Ab-positive, 78 of whom were also positive for HCV RNA (76.5%; 95%CI, 67.4-83.6%). Between 2015 and 2019, 48 patients were HCV-Ab-positive, 23 of whom were also positive for HCV RNA (47.9%; 95%CI, 34.5-61.7%; p = 0.0007 compared with 2009-2014). In the era of IFN-free DAAs, 9 of 23 HCV RNA-negative patients (39.1%) and 2 of 22 HCV RNA-positive patients (9.1%) were treated with an IFN-free combination of DAAs (p = 0.0351). Regarding the departments where NSIs occurred, HCV RNA-negative patients were predominant in departments not related to liver diseases in the era of IFN-free DAAs (p = 0.0078, compared with 2009-2014). CONCLUSIONS: Actual HCV RNA positivity in source patients of NSIs decreased after the emergence of IFN-free DAAs. IFN-free DAAs might have contributed to this reduction, and HCV RNA-negative patients were predominant in departments not related to liver diseases in the era of IFN-free DAAs.

First human case of catheter-related blood stream infection caused by Staphylococcus schleiferi subspecies coagulans: a case report and literature review.

BACKGROUND: Staphylococcus schleiferi is a gram-positive pathogenic coccus which causes canine skin and ear infections. Only four cases of human infection caused by Staphylococcus schleiferi subspecies coagulans have been reported. Herein, we present the first case of catheter-related bloodstream infection caused by S. schleiferi subspecies coagulans. CASE PRESENTATION: A 62-year-old Japanese man was admitted to our hospital for examination of sigmoid colon tumor. During hospitalization, he had fever, shaking chills, and swelling at the peripheral venous catheter insertion site. Two sets of blood cultures were positive for S. schleiferi subspecies coagulans which was confirmed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), 16S ribosomal RNA sequencing and the coagulase test. The patient was successfully treated without relapse. CONCLUSION: To our knowledge, this is the first report of catheter-related bloodstream infection caused by S. schleiferi subspecies coagulans. S. schleiferi subsp. coagulans can be pathogenic in humans, and MALDI-TOF MS can contribute to accurate identification of S. schleiferi subspecies coagulans.

Dynamic changes in fibrinogen and D-dimer levels in COVID-19 patients on nafamostat mesylate.

Critical illnesses associated with coronavirus disease 2019 (COVID-19) are attributable to a hypercoagulable status. There is limited knowledge regarding the dynamic changes in coagulation factors among COVID-19 patients on nafamostat mesylate, a potential therapeutic anticoagulant for COVID-19. First, we retrospectively conducted a cluster analysis based on clinical characteristics on admission to identify latent subgroups among fifteen patients with COVID-19 on nafamostat mesylate at the University of Tokyo Hospital, Japan, between April 6 and May 31, 2020. Next, we delineated the characteristics of all patients as well as COVID-19-patient subgroups and compared dynamic changes in coagulation factors among each subgroup. The subsequent dynamic changes in fibrinogen and D-dimer levels were presented graphically. All COVID-19 patients　were classified into three subgroups: clusters A, B, and C, representing low, intermediate, and high risk of poor outcomes, respectively. All patients were alive 30 days from symptom onset. No patient in cluster A required mechanical ventilation; however, all patients in cluster C required mechanical ventilation, and half of them were treated with venovenous extracorporeal membrane oxygenation. All patients in cluster A maintained low D-dimer levels, but some critical patients in clusters B and C showed dynamic changes in fibrinogen and D-dimer levels. Although the potential of nafamostat mesylate needs to be evaluated in randomized clinical trials, admission characteristics of patients with COVID-19 could predict subsequent coagulopathy.

Changing trends in lipid profile and biomarkers of renal function and bone metabolism before and after switching from tenofovir disoproxil fumarate to tenofovir alafenamide: a prospective observational study.

BACKGROUND: Antiretrovirals, including tenofovir, can suppress human immunodeficiency virus (HIV) infection but cannot completely eradicate it. Patients with HIV infection are administered antiretroviral drugs over a long term; thus, managing consequent adverse drug reactions, such as renal dysfunction and bone mineral loss, is important. Currently, highly sensitive biomarkers that can detect adverse drug reactions early have not been well studied. METHODS: This single-center, prospective, observational study explored changes in the biomarkers of renal function, bone metabolism, and lipid profile before and after switching from tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide (TAF) in patients with HIV infection. RESULTS: All 31 enrolled patients had been treated with antiretrovirals for more than 5 years. The rate of proteinuria decreased significantly after starting TAF-containing antiretroviral regimen. The urinary liver-type fatty acid binding protein (L-FABP)/creatinine ratio was significantly decreased at 3 and 6 months after switching to TAF compared with that before switching to TAF (- 0.5 µg/g Cr at 3 months, and - 0.8 µg/g Cr at 6 months; p < 005 for both at 3 and 6 months). The urinary N-terminal telopeptide (NTx)/creatinine ratio decreased over the study period, and the ratios were significantly different between 3 and 6 months (- 11 nmol/mmol Cr at 3 months, - 15.2 nmol/mmol Cr at 6 months; p = 0.0069 at 3 months, p < 0.0001 at 6 months). Low density lipoprotein-cholesterol level significantly increased at 3 (+ 26 mg/dL) and 6 months (+ 13 mg/dL) compared with that at the baseline (p < 0.0001). CONCLUSIONS: Switching from TDF to TAF decreased the levels of renal and bone biomarkers, such as urinary L-FABP and NTx, but increased low density lipoprotein-cholesterol levels. Future studies should evaluate if these biomarkers, such as urinary L-FABP and NTx, truly detect serious adverse drug reactions early.

Microbiological analysis of infectious lymphocele: Case series and literature review.

BACKGROUND: Infectious lymphocele is a rare post-operative complication of abdominal surgery, and few studies have focused on its causative organisms. The aim in this research is to clarify microbiology and appropriate empiric treatment of infective lymphocele. METHODS: We performed a single center, retrospective observational study between April 2000 and March 2018 with a case review and literature search. Data were collected in a chart review. RESULTS: Twenty-four cases were founded in our institution. 153 cases, including 16 cases from our institution, that detected causative organisms was also analyzed. Infectious lymphocele was found to occur post gynecological/urological surgery in cancer patients. We also reported that bacteremia incidence and the mortality rate of infectious lymphocele cases were very low. The major sites of infectious lymphocele were pelvis or inguinal area. Our case series and literature review showed Gram positive cocci were the major causative organisms, with Staphylococcus aureus constituting one third of them (53/153 cases). Streptococcus species (26/153cases) and coagulase negative Staphylococci (17/153 cases) were the second and third most detected organisms. CONCLUSION: In gynecologic and urologic cancer patients, Gram positive cocci were the most common organisms causing lymphocele infection. Gram-positive coverage might be reasonable for empiric therapy in infectious lymphocele.

A rare case of a prostatic abscess, bacteremia and chronic granulomatous disease associated with Klebsiella pneumoniae.

Chronic granulomatous disease (CGD) is a primary immunodeficiency disease characterized by severe recurrent infections such as pneumonia, liver and skin infections. However, prostatic abscesses are rare as only two cases have been reported thus far. We present the case of a 41-year-old patient with CGD who was admitted to the hospital with fever and subsequently, Klebsiella pneumoniae was identified on blood culture. Abdominal computed tomography revealed a prostatic abscess. He improved with intravenous antibiotics and drainage of the abscess. After he was taken off the intravenous antibiotics and started on an oral agent, he was discharged from the hospital. We confirmed a reduction in the prostatic abscess size and continued the antibiotic therapy for 52 days. A prostatic abscess is an uncommon disease being diagnosed at a median age of 49 years. Sometimes it is discovered in patients with fever of unknown origin and might be considered as an infection site of CGD patients.

Pyogenic liver abscess due to hypervirulent Klebsiella pneumoniae in a 14-year-old boy.

A 14-year-old otherwise healthy boy presented with right-sided back pain following high fever. Abdominal computed tomography scan showed a large liver abscess. Klebsiella pneumoniae (KP) was rapidly identified from peripheral blood using the melting temperature mapping (Tm) method, which enables identification of pathogenic microorganisms within four hours after patient sample collection. He was diagnosed with pyogenic liver abscess (PLA) caused by KP on the day of admission. The KP was the hypervirulent (hv) clinical variant (string test positive, serotype K1, sequence type 23, rmpA and magA positive). After intravenous antibiotic therapy and drainage of the abscess, his condition resolved. The highlights of this case report are a healthy child with hypervirulent Klebsiella pneumoniae liver abscess in Japan and the new Tm mapping method for rapid and accurate identification of the pathogenic microorganism.

Three cases of Candida fermentati fungemia following hematopoietic stem cell transplantation.

Bloodstream infection with non-Candida albicans Candida species is one of the serious complications among patients with hematological malignancies who receive long-term prophylactic antifungal agents. Here we describe three cases of Candida fermentati (C. fermentati) candidemia after allogeneic stem cell transplantation for hematological malignancies. Case 1 is fluconazole-breakthrough C. fermentati fungemia, which was well controlled with liposomal amphotericin B. Case 2 and 3 were caspofungin-breakthrough C. fermentati fungemia. In case 2, blood culture turned negative for Candida responding to liposomal amphotericin B. Although in vitro susceptibility data for the isolated pathogen suggested the efficacy of both caspofungin and liposomal amphotericin B in all three cases, clinically liposomal amphotericin B seemed to have been more effective for eradication of the pathogen from blood stream. C. fermentati needs to be considered as a possible cause for breakthrough candidemia among post-transplant patients with prolonged antifungal prophylaxis. Discrepancy between in vitro and in vivo susceptibility to antifungals, especially to echinocandins, might provide a clue for the optimal choice of antifungals for C. fermentati infections.

Bilateral Candida endophthalmitis accompanying Candida lusitaniae bloodstream infection: A case report.

Candida lusitaniae is an uncommon cause of candidiasis in humans. Ocular manifestations of C. lusitaniae infection have not been reported. C. lusitaniae is either intrinsically resistant to amphotericin B or can acquire such resistance. We describe a case of bilateral endophthalmitis due to C. lusitaniae bloodstream infection in a liver transplant patient with rectal cancer. The patient suffered fungemia and endophthalmitis and was treated with liposomal amphotericin B. The isolate was identified as C. lusitaniae by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, the system based on biochemical tests, and sequencing of the internal transcribed spacer region. The minimal inhibitory concentrations were 0.06 µg/mL for amphotericin B and 2.0 µg/mL for fluconazole. Repeat blood cultures were negative and the endophthalmitis improved following treatment with liposomal amphotericin B. However, the treatment was changed to fluconazole due to nephrotoxicity. No recurrence occurred after completion of treatment.

A therapeutic benefit of daptomycin against glycopeptide-resistant gram-positive cocci bloodstream infections under neutropenia.

Antibiotic-resistant infections remain to be a major issue for all over the world. Although appropriate diagnosis and rapid treatment initiation are crucially important particularly in immunocompromised patients, selection of antibiotics without identification of causative bacteria is often challenging. A 44-year-old woman with acute myeloid leukemia (AML) under myelosuppression suffered from teicoplanin-resistant gram-positive cocci bacteremia. Taking severe neutropenia due to chemotherapy and glycopeptide-resistance into account, teicoplanin was empirically substituted with daptomycin, which led to prompt defervescence. This microorganism later turned out to be Leuconostoc lactis (L. Lactis), and daptmycin was continued to use based on antimicrobial susceptibility tests. As a result, empiric use of daptomycin successfully controlled glycopeptide-resistant gram-positive cocci bacteremia under neutropenia. This is the first report of daptomycin treatment for L. lactis bacteremia in a patient with AML under neutropenia. Our findings suggest that daptomycin would be a suitable treatment option for glycopeptide-resistant gram-positive cocci bloodstream infections, especially in myelosuppressive patients.

Catheter-related bloodstream infection caused by Kodamaea ohmeri: A case report and literature review.

Kodamaea ohmeri is a rare yeast pathogen that has recently emerged as an important cause of fungemia in immunocompromised patients. However, appropriate therapy for this infection remains unclear. We report a case of catheter-related blood stream infection caused by K. ohmeri in a 58-year-old patient who improved after removal of the central venous catheter and administration of micafungin. Considering the antibiotic susceptibility of this pathogen and reviewing literature, echinocandins may be the first choice for an empiric therapy for this pathogen.

Novel interferon-based pre-transplantation conditioning in the treatment of a congenital metabolic disorder.

Hematopoietic stem cell (HSC) gene therapy is a potentially curative treatment modality for monogenic hematological diseases and storage disorders. It is necessary, however, to establish pre-bone marrow (BM) transplant conditioning regimens that minimize DNA damage and toxicity. Type I interferon (IFN) signaling activates quiescent HSCs and enables them to be sensitive to 5-fluorouracil (FU)-mediated cytotoxicity, thus implying a molecular basis for improving HSC transplant outcomes. Here we show that type I IFN preconditioning, without irradiation or DNA alkylating agents, significantly enhanced the HSC engraftment efficiency in wild-type (WT) recipient mice. The importance of active type I IFN signaling in HSC recipients was further demonstrated using mice lacking IFN regulatory factor 2 (IRF2), a transcriptional suppressor of type I IFN signaling. In both WT and Irf2(-/-) recipients, active type I IFN signaling greatly enhanced the sensitivity to 5-FU or low-dose irradiation of HSCs. Importantly, IFN-based pre-BM transplant conditioning was also applicable to the treatment of Sly syndrome, a congenital storage disorder with ß-glucuronidase deficiency, in which it restored enzyme expression at the HSC level and reciprocally reduced pathological glycosaminoglycan storage. Our findings suggest type I IFN-based preconditioning, combined with HSC transplantation, as a novel nongenotoxic treatment of some congenital diseases.

Clinical characteristics and antimicrobial susceptibility of Bacillus cereus blood stream infections.

BACKGROUND: Bacillus cereus is one of the pathogens causing nosocomial bloodstream infections (BSIs). However, few reports have documented the antimicrobial susceptibility and clinical characteristics of Bacillus cereus BSI and the importance of empirical therapy. The aim of this study was to investigate the clinical characteristics and antimicrobial susceptibility of B. cereus isolates from patients with BSI and to analyze the impact of appropriate empirical therapy on the outcome of patients with B. cereus BSI. METHODS: All adult cases of bacteremia between April 2003 and March 2012 in a teaching hospital in Tokyo, Japan were reviewed retrospectively. Clinical data were collected from the patients' medical records and charts. Antimicrobial susceptibility testing was performed by broth microdilution method. The patients with B. cereus BSI were divided into an appropriate empirical therapy group and an inappropriate empirical therapy group. The primary outcome was all-cause mortality at 4 weeks after the start of BSI. The secondary outcome was early defervescence within 2 days after starting empirical therapy. RESULTS: There were 29 B. cereus bloodstream infection cases. No vancomycin, gentamicin, and imipenem-resistant isolates were found. However, 65.5 % were resistant to clindamycin and 10.3 % were resistant to levofloxacin. The main etiology was venous catheter-related (69 %). All-cause mortality at 4 weeks was not significantly different between the appropriate empirical therapy group (9 cases) and the inappropriate group (20 cases) in this study. However, early defervescence within 2 days after starting empirical therapy was significantly different (p = 0.032). CONCLUSIONS: The BSI of B. cereus is mostly caused by venous catheter-related infections. Appropriate empirical therapy is important to achieve early clinical resolution in B. cereus BSI. Vancomycin is one of the appropriate selections of empirical therapy for B. cereus BSI.