Kiyofumi Ohkusu

Direct identification of microorganisms from positive blood cultures by MALDI-TOF MS using an in-house saponin method

OBJECTIVESnMatrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a fast and reliable method for the identification of bacteria. A MALDI Sepsityper kit is generally used to prepare samples obtained directly from culture bottles. However, the relatively high cost of this kit is a major obstacle to introducing this method into routine clinical use. In this study, the accuracies of three different preparation methods for rapid direct identification of bacteria from positive blood culture bottles by MALDI-TOF MS analysis were compared.nnnMETHODSnIn total, 195 positive bottles were included in this study.nnnRESULTSnOverall, 78.5%, 68.7%, and 76.4% of bacteria were correctly identified to the genus level (score ≥1.7) directly from positive blood cultures using the Sepsityper, centrifugation, and saponin methods, respectively. The identification rates using the Sepsityper and saponin methods were significantly higher than that using the centrifugation method (Sepsityper vs. centrifugation, p<0.001; saponin vs. centrifugation, p=0.003).nnnCONCLUSIONSnThese results suggest that the saponin method is superior to the centrifugation method and comparable to the Sepsityper method in the accuracy of rapid bacterial identification directly from blood culture bottles, and could be a less expensive alternative to the Sepsityper method.

Recurrence of Disseminated Mycobacterium avium Complex Disease in a Patient with Anti-Gamma Interferon Autoantibodies by Reinfection

ABSTRACT We report a case of recurrent disseminated Mycobacterium avium complex (DMAC) disease with anti-gamma interferon autoantibodies. To our knowledge, this is the first reported case caused by reinfection with a separate isolate of M. avium. DMAC disease activity was monitored using serum IgG antibody titers against lipid antigens extracted from a MAC strain.

First case report of infection due to Cupriavidus gilardii in a patient without immunodeficiency: a case report

BackgroundCupriavidus gilardii is an aerobic, Gram-negative, glucose-nonfermenting rod that was first identified in 1999. Because of the difficulty in accurate species identification of C. gilardii, there are few case reports of infection caused by this organism. In previous reports, C. gilardii has been characterized as an organism with low pathogenicity that causes opportunistic infections.Case presentationWe encountered a case of pacemaker-associated bloodstream infection caused by C. gilardii in a 90-year old woman without obvious immunodeficiency. We identified the isolates as C. gilardii by sequencing of the 16S rRNA gene. The patient was treated with removal of the lead and administration of antimicrobial agents. Because of the acquisition of antibiotic resistance during antibiotic treatment, the antimicrobial agent was changed during the course of treatment.ConclusionsTo our knowledge, this is the first report of an infection caused by this organism in a patient without obvious immunodeficiency. Although the true pathogenicity of C. gilardii is unclear, the possibility that it exerts pathogenicity not only in persons with immunodeficiency but also in immunocompetent persons is suggested.

Blood stream infections caused by Acinetobacter baumannii group in Japan – Epidemiological and clinical investigation

Acinetobacter calcoaceticus-Acinetobacter baumannii complex, especially A.xa0baumannii, Acinetobacter pittii and Acinetobacter nosocomialis, constitutes an important group of nosocomial pathogens; however, epidemiological or clinical characteristics and prognosis is limited in Japan. From 2009 to 2013, 47 blood stream infection cases resulting from A.xa0baumannii group were reviewed at the National Defense Medical College, an 800-bed tertiary hospital. To determine the genospecies, further comparative nucleotide sequence analyses of the RNA polymerase b-subunit (rpoB) gene were performed. Sequence analysis of rpoB gene showed that 25 (49.0%), 17 (33.3%) and 5 (9.8%) cases were caused by A.xa0baumannii, A.xa0pittii and A.xa0nosocomialis, respectively. The 30-day and in-hospital mortality rates of A.xa0baumannii were 8.5% and 25.5%, respectively, and there were no significant differences between Acinetobacter species. Clinical characteristics were statistically insignificant. Multidrug-resistant Acinetobacter species were detected in 3 cases (5.9%) with same pulsed-field gel electrophoresis (PFGE) pattern and A.xa0baumannii was less susceptible to amikacin and levofloxacin. In this study, the mortality and clinical characteristics were similar among A.xa0baumannii group isolate cases despite some showing drug resistance. However, identification of Acinetobacter species helps to initiate appropriate antibiotic therapy in earlier treatment phase, because A.xa0baumannii shows some drug resistance.

First case report of fatal sepsis due to Campylobacter upsaliensis

ABSTRACT We encountered a rare case of severe fatal infection in a 70-year-old woman due to Campylobacter upsaliensis, identified by PCR amplification and sequencing analysis of the 16S rRNA gene using DNA extracted from the isolates. To our knowledge, fatal sepsis due to this organism has never been described to date.

Seven cases of localized invasive sino-orbital aspergillosis

PurposeTo describe the clinical manifestations and prognoses in 7 patients with invasive sino-orbital aspergillosis (ISOA).MethodsThis was a retrospective study of consecutive patients who were diagnosed as having ISOA at the Gifu University Hospital and Gifu Municipal Hospital between January 1993 and December 2015. Data were collected on demographics, initial manifestations, examination findings, treatments, clinical course, and outcomes.ResultsThe median age of the 7 patients with ISOA was 68xa0years; 5 of them had diabetes. The initial symptoms were reduced blurred vision (57%), unilateral headaches (43%), unilateral abnormal sensations or numbness of the periorbital area (43%), and external ophthalmoplegia (43%). The medical department that the patients first visited was the ophthalmology department in 57% of the cases. The initial CT showed bone destruction in 71% and calcification in 14% of the patients. Six of the 7 cases were misdiagnosed. The definitive diagnosis of ISOA was made by histopathologic examinations of the biopsy specimens, with an average of 2.6 biopsies. All patients received aggressive antifungal treatments after the diagnosis. However, the final visual outcome was no light perception in 86% and death related to the ISOA in 43% of the patients. Patients who were older at the onset had lower survival rates.ConclusionsThe prognosis for patients with ISOA is poor in terms of both vision and life. Ophthalmologists are often the first examiner. ISOA should be considered in the differential diagnosis for patients with a gradually progressive orbital mass, unilateral headaches, numbness of the periorbital area, and a decrease in visual acuity of unknown origin.

The first case report of cerebral cyst infection due to Helicobacter cinaedi.

We report the first case of cerebral cyst infection by Helicobacter cinaedi, a fastidious spiral-shaped gram-negative rod bacterium. A 70-year-old man visited Tokyo Medical University Hospital with persisting fever since 2 weeks. He underwent surgery and radiotherapy for parapharyngeal space squamous cell carcinoma 10 years ago. The radiotherapy resulted in a cerebral cyst as a side effect, and an Ommaya reservoir was inserted into the cyst. Blood culture and analysis of the brain cyst fluid revealed the presence of spiral-shaped gram-negative rod bacteria, which were identified as H. cinaedi by polymerase chain reaction. Initially, we administered clarithromycin (400 mg per day). After H. cinaedi infection was confirmed, the treatment was changed to meropenem (MEPM 6 g per day). The patient was treated for 43 days in the hospital with intravenous meropenem, and his clinical course was satisfactory. On the 44th day, he was discharged and prescribed oral minocycline (MINO 200 mg per day). After discharge, the patients H. cinaedi infection did not recur. Our case illustrated the wide clinical spectrum of H. cinaedi as well as the effectiveness of antibiotic therapy comprising MERM and MINO for treating central nervous system infection by this organism.

Disseminated Mycobacterium genavense infection in patient with adult-onset immunodeficiency

We report a case of disseminated Mycobacterium genavense infection resulting from neutralizing anti–interferon-γ autoantibodies in the patient. We identified M. genavense targeting the hsp65 gene in an aspiration specimen of the lymph node. Adult-onset immunodeficiency caused by neutralizing anti–interferon-γ autoantibodies, in addition to HIV infection, can lead to disseminated nontuberculous mycobacterial infection.

Phanerochaete sordida as a cause of pulmonary nodule in an immunocompromised patient: a case report

BackgroundPhanerochaete sordida is a species of wood rotting fungus, which can degrade lignin, cellulose and hemicellulose contained in wood and other hard-to-biodegrade organic substances. However, to date, there have been no other reports demonstrating that P. sordida can infect humans.Case presentationA 66-year-old Japanese man presented for a mass increasing in size on his left thigh. He had been suffering from rheumatoid arthritis for 18xa0years and chronic obstructive pulmonary disease for 20xa0years, for which he was being treated with 5xa0mg/day prednisolone and 8xa0mg/week methotrexate. The mass resection was performed two months later, and was diagnosed as malignant fibrous histiocytosis. However, a computed tomography examination for tumor recurrence after surgery showed a newly emergent pulmonary nodule. We therefore decided to resect the nodule by thoracoscopic procedure. Histopathological examination of the excised specimen showed that the lesion was a granuloma, with necrotic tissue and clumping of Aspergillus-like hyphae. Therefore, the nodule was diagnosed as a fungal infection and tissue specimens were cultured microbiologically. However, fungal growth was not observed. We consequently performed genetic analysis using a broad-range polymerase chain reaction. The 28S rRNA sequence demonstrated 100% homology with P. sordida using the NCBI BLAST program against the GenBank DNA databases.ConclusionsUsing broad-range polymerase chain reaction, we identified P. sordida as the causative agent of a pulmonary nodule. These findings indicate that P. sordida may be an additional opportunistic causative organism of pulmonary infection in immunocompromised patients.

Case of late-onset bleb associated endophthalmitis caused by Rothia mucilaginosa

Rothia mucilaginosa is a gram-positive coagulase-negative coccus of the family Micrococcaceae. Although R.xa0mucilaginosa forms part of the oropharyngeal microflora, it has only recently been isolated in ocular infections. We report a case of a 41-year-old man who developed late-onset bleb-related endophthalmitis (BRE). He had undergone glaucoma surgery 21 years earlier and had a thin-walled cystic bleb prior to the development of endophthalmitis in his right eye. He immediately received intravitreal injections of ceftazidime and vancomycin, topical levofloxacin and cefmenoxime, and intravenous cefozopran. Culture of the aqueous humor specimen identified R. mucilaginosa by 16S rRNA sequence analysis. To our knowledge, this is the first report of late-onset BRE caused by R.xa0mucilaginosa. Our case indicates that R.xa0mucilaginosa can be a cause of late-onset BRE, and that molecular analysis is an accurate method to identify R.xa0mucilaginosa.