Clostridium difficile 関連下痢症（C.difficile-associated diarrhea : CDAD）の診断には，糞便中のtoxin A のみならずtoxinA および/あるいはtoxinB の両毒素検出キットが用いられるようになった．我々は，市販検出キットとしてtoxinA および/あるいはtoxinB の両毒素検出キットであるC.difficile TOX A/B II test （TOX A/BII）ならびにtoxin A 検出キットであるクロストリジウムトキシンA 検出キット「ユニクイック」（ユニクイック）の性能を確認する目的で，①精製されたtoxin A を用いた検出感度試験，②toxin A およびtoxin B を産生，toxin A は産生しないがtoxin B を産生，および両毒素とも産生しないC.difficile 菌株，およびC.difficile 以外の菌株を用いた特異度試験，③臨床検体を用いた感度ならびに特異度試験を実施した．その結果，TOX A/BII ならびにユニクイックにおけるtoxin A 検出感度は，各々0.35ng/mL，0.7ng/ mL であった．また，前述の毒素産生パターンの異なるC.difficile 菌株およびC.difficile 以外の菌株培養上清を用いた特異度評価より，ユニクイックはtoxin A 産生を，またTOX A/BII はtoxin A，toxin B の両毒素あるいはそれぞれ単独の毒素を特異的に検出できることが確認された．臨床検体を用いた感度，特異度試験では，toxin B 産生性C.difficile 分離同定法により当該菌の存在が確認された43 検体ならびに分離されなかった56 検体に対するTOX A/BII のsensitivity，specificity，positive predictive value，negative predictive value はそれぞれ95.3％，98.2％，97.6％および96.5％であり，ユニクイックのそれ（76.7％，98.2％，97.1％および84.6％）に比べ検出感度が高かった．以上の成績より，TOX A/BII による検査結果は毒素産生性C. difficile 分離培養検査結果とよく一致し，CDAD の診断のために有用であることが示唆された．しかしながら，臨床検体からの毒素検出検査のみに頼らず，培養検査を併用することも重要であると考えられた．
We report a rare case of toxoplasmic encephalitis in a non-AIDS patient. A 62-year-old man undergoing hemodialysis for seven months and corticosteroid therapy for rapidly progressive glomerulonephritis and admitted for generalized convulsions was found in cranial magnetic resonance imaging (MRI) to have multiple ring-enhanced lesions. Antibodies against Toxoplasma gondii, and in Sabin-Feldman dye test were extremely high, yielding a diagnosis of toxoplasmic encephalitis. He was also diagnosed as having cytomegaloviral retinitis. Anti-HIV antibody was negative. Treatment with pyrimethamine and clindamycin was effective and intracerebral lesions disappeared. Physicians encounting a similar situation should consider toxoplasmic encephalitis as a differential diagnosis, even in non-HIV patients, and implement confirmational examination.
A 78-year-old man administered prednisolone and cyclosporin A for bullous pemphigoid and found in computed tomography (CT) to have a left-lung nodule was suspected of having a fungal infection due to elevated blood (1→3)-β-D-glucan. Despite empirical antifungal therapy, however, the nodule grew, followed by new nodules in both lungs. Disseminated nocardiosis was eventually diagnosed based on sputum, blood, and skin cultures growing Nocardia sp. Antinocardial treatment with imipenem/cilastatin and amikacin was started. The patient then developed pneumocystis pneumonia for which pentamidine was added. He had recovered completely when antimicrobial therapy was completed. A wide variety of microorganisms may infect patients with impaired cellular immunity, simultaneously involving multiple organisms in some cases. Definitive microbiological diagnosis with culture or biopsy specimens is therefore crucial for appropriate management.
Streptococcus suis, a major global porcine pathogen, is an emerging zoonosis in Southeast Asia that triggered a 2005 outbreak in China. S. suis causes meningitis, sepsis, and endocarditis in both pigs and humans and involves significant mortality. We report the case of a previously healthy 50-year-old dairy farmer who developed S. suis type 2 endocarditis complicated by pulmonary embolism and spondylitis. He experienced a high fever, chills, fatigue, and worsening low back pain in the 6 weeks prior to admission. On physical examination, he had lumbar spine tenderness and weakness of the left leg. Blood culture identified penicillin sensitive S. suis type 2. Echocardiography showed vegetation on the tricuspid valve, and magnetic resonance imaging (MRI) showed signs of spondylitis. The man reported sudden chest pain several days after admission, which computed tomography (CT) showed what was diagnosed as a septic pulmonary embolism. He was treated with penicillin G for 4 weeks and gentamicin for the first 2 weeks, followed by 2 weeks of oral amoxicillin, after which his symptoms gradually improved. The infection source was probably his dairy herd, since calves often bit his fingers while feeding and S. suis was found in their oral mucus. Over 400 cases of human S. suis infection have been reported globally, but this is, to our knowledge, the first known case of bovine transmission. All of Japanʼs 8 other cases involved occupational swine exposure, 5 of whom had injuries to their fingers. This emerging situation should be made known to all possibly involved in unprotected direct contact with swine and cattle, particularly when the skin could be compromised by cuts or abrasions.
A 40-year-old man undergoing allo-hematopoietic stem cell transplantation for chronic myelogenous leukemia and developing diarrhea was administered prophylactic antibiotics including levofloxacin, fluconazole, cotrimoxazole, and vancomycin. Stool specimens were positive for toxin A in enzyme immunoassay but negative for toxin B in cell culture assay with a neutralization test, indicating that toxin A detection was false-positive. Stool culture yielded enterotoxin producing Clostridium perfringens, not Clostridum difficile. Polymerase chain reaction (PCR) detected the gene encoding C. perfringens enterotoxin in DNA extracted from stool specimens, but not the toxin B gene. Laboratory tests for enterotoxic C. perfingens may therefore be necessary for diagnosing antibiotic-associated diarrhea when culture for C. difficile is negative.
Shewanella algae is an aquatic gram-negative bacterium, rarely recovered from human clinical samples. Case reports of human Shewanella infection are, however, slowly increasing, and a Shewanella infection outbreak was reported at a South Korean hospital. We report the case of an 89-year-old man admitted for back pain and fever after eating raw marine fish. Sulbactam/cefoperazone was started under a tentative diagnosis of gall bladder inflammation with gallstones based on ultrasonographic findings. His persistent back pain,however, necessitated vertebral magnetic resonance imaging (MRI), which showed thoracic vertebral osteomyelitis and discitis. Two sets of blood culture on admission yielded a gram-negative bacillus identified as “Shewanella putrefaciens”by automated identification. Ceftriaxone administration for 3 weeks followed by oral levofloxcin for 5 weeks cured the vertebral osteomyelitis and discitis. 16S rRNA sequence analysis showed that “S. putrefacien”was, in fact, S. algae-incorrectly detected because semi-automated and automated identification did not include S. algae in their database. It should thus be kept in mind that consuming raw-fish may cause Shewanella bacteremia and osteomyelitis in patients with hepatobiliary disease and that genetic analysis is required to precisely determine the occurrence of Shewanella spp.
Domestic animals are the main reservoirs of Pasteurella species for human zoonosis due to bites and scratches. Pasterurella multocida may cause serious soft-tissue infection and, less commonly, sepsis or septic shock, particularly in insufficient initial therapy and an immunocompromised host. We report a case of catscratch-induced P. multocida infection, presenting with disseminated intravascular coagulation and acute renal failure. A febrile 83-year-old woman with consciousness disturbance and a subcutaneous left-foot abscess due to a scratch from a pet cat. She was successfully treated with antibiotic piperacillin and clindamycin therapy and aggressive wound drainage.
Ventriculo-atrial shunt infection (VASI) may lead to sepsis and/or nephritis, making early diagnosis critical. VASI is usually diagnosed by cerebrospinal fluid culture conducted after ventricular puncture or shunt removal, both of which are invasive. Non-invasive attempts at diagnosis, however, present a nonspecific clinical picture unless shunt dysfunction is present. A 57-year-old woman treated with ventriculo-atrial shunt 10 months earlier due to hydrocephalus following subarachnoid hemorrhage developed a fever but evidenced no infected organs in general examination although Staphylococcus epidermidis was isolated several times upon blood culture. Enhanced brain computed tomography (CT) showed neither abnormal findings nor changes in ventricular size and no shunt dysfunction was demonstrated clinically. In cerebrospinal fluid examination, the protein level was 137mg?dL and cell count and bacteriological findings were normal. 10 days later, however, the cell count and bacteriological findings were normal but protein was 180mg/dL. The cerebrospinal fluid protein increase indicated VASI, and the shunt was removed. The womanʼs fever was immediately alleviated and Staphylococcus epidermidis was detected in the cerebrospinal fluid culture of the specimen from the shunt tip and its periphery. Blood culture is useful for identifying bacterial etiology of VASI if neither cerebrospinal fluid cell count increases nor abnormal bacteriological findings are observed, provided that cerebrospinal fluid protein in crease are observed in serial measurement.