Rapid tumor progression complicated with liver abscess in a patient with gastric cancer receiving nivolumab therapy.

Immune checkpoint inhibitors have been approved for treating various cancer types. However, several studies reported rapid tumor progression, a condition known as hyperprogressive disease, after treatment with immune checkpoint inhibitors. We present the case of a 73-year-old man diagnosed with recurrent gastric cancer with liver and lymph node metastases detected in the presence of obstructive jaundice. Concomitant administration of nivolumab with cytotoxic chemotherapy as first-line chemotherapy effectively controlled the tumor. Nevertheless, once cytotoxic chemotherapy was discontinued and nivolumab monotherapy was initiated to treat liver abscess complications, the tumor rapidly progressed, ultimately leading to the patient's death. This is the first report on rapid tumor growth observed during subsequent treatment with nivolumab after initial antitumor effects were confirmed. This case report describes the possibility of rapid tumor growth in patients receiving immune checkpoint inhibitor therapy, including in cases where this therapy showed antitumor efficacy in the initial therapeutic evaluation. Therefore, patients receiving immune checkpoint inhibitor therapy need to be monitored.

Vertebral Osteomyelitis Caused by Mycobacterium arupense Mimicking Tuberculous Spondylitis: First Reported Case and Literature Review.

Mycobacterium arupense is a slow-growing, nontuberculous mycobacterium widely found in the environment and is known to cause tenosynovitis and osteomyelitis, mainly in the hands and wrists. We present the first case of vertebral osteomyelitis caused by M arupense in a 78-year-old man with renal cell carcinoma. The patient had a history of tuberculous pleuritis in childhood. Although the nucleic acid amplification test of the vertebral tissue for Mycobacterium tuberculosis was negative, we initiated tuberculosis treatment based on the history and pathological findings of auramine-rhodamine-positive organisms and epithelioid cell granulomas. Subsequently, the isolated mycobacterium was identified as M arupense by genome sequencing. Accordingly, the treatment regimen was changed to a combination of clarithromycin, ethambutol, and rifabutin. Owing to a subsequent adverse event, rifabutin was switched to faropenem, and the patient was treated for a total of 1 year. In previous literature, we found 15 reported cases of bone and soft tissue infections caused by M arupense, but none of them had vertebral lesions. Physicians should be aware that M arupense can cause vertebral osteomyelitis mimicking tuberculous spondylitis. In addition, molecular testing of isolated mycobacteria is essential for diagnosis, even if tuberculous spondylitis is suspected.

A Challenging Case of Streptococcus pneumoniae Meningitis in a 64-Year-Old Woman Who Presented with Symptoms of Cerebellar Hemorrhage.

BACKGROUND There is a recognized association between bacterial meningitis and intracranial hemorrhage. However, acute neurological symptoms at presentation, with confirmation of hemorrhage on imaging, may delay further investigations, including blood culture for diagnosing an infection. This report presents a challenging case of Streptococcus pneumoniae meningitis in a 64-year-old woman who presented with symptoms of cerebellar hemorrhage. CASE REPORT This report describes a 64-year-old woman who had a medical history of untreated diabetes mellitus. She was brought to our hospital with headache and impaired consciousness, complicated with fever. Based on the hemorrhage in the left cerebellar hemisphere detected in the head CT findings, the patient was initially diagnosed with cerebellar hemorrhage. However, a positive blood culture after 12 hours of admission made the physician consider a central nervous system infection as the cause of the hemorrhage and perform a lumbar puncture. Therefore, the patient was diagnosed with acute bacterial meningitis caused by Streptococcus pneumoniae, and antibiotic treatment was started immediately. Although her general condition improved after antibiotic treatment, her mental status did not improve completely. CONCLUSIONS This report highlights that the clinicians should be aware that bacterial meningitis may result in intracranial hemorrhage. Patients with symptoms of a hemorrhagic stroke should be thoroughly investigated to avoid a delay in the treatment of infection.

Ecthyma gangrenosum caused by Staphylococcus aureus in hematological malignancies: Case reports and literature review.

RATIONALE: Ecthyma gangrenosum (EG) is a potentially life-threatening, systemic infection generally caused by Pseudomonas aeruginosa. Data on EG caused by Staphylococcus aureus in patients with hematological malignancies are scarce. The present case report aimed to describe the clinical features of EG caused by S. aureus in patients with hematological malignancies and to provide a comprehensive review of previous studies on the topic. PATIENT CONCERNS: The first patient was a 61-year-old man with acute myeloid leukemia who presented fever and multiple lesions during chemotherapy. The second patient was a 47-year-old man with myelodysplastic syndrome who developed progressive erythematous necrotic plaques on his extremities and face. DIAGNOSIS: Both cases were diagnosed as EG caused by S. aureus. While the first patient had concurrent methicillin-resistant S. aureus (MRSA) bacteremia, the second patient had positive results only for tissue culture of the skin lesion isolated methicillin-sensitive S. aureus. INTERVENTIONS: Vancomycin was initiated with critical care to the first patient. Cefazolin was administered to the second patient for 3 weeks, followed by cephalexin for 1 week. OUTCOMES: The first patient died of a brain hemorrhage and multiple organ failure. The second patient was cured without relapse. LESSONS: Of 18 patients in the previous and current studies with EG caused by S. aureus, 6 (33%) had an underlying hematological malignancy, and 10 (56%) had EG caused by MRSA. While 28% of the patients had positive blood cultures, all tissue cultures were positive. All 3 fatalities had concurrent bacteremia (MRSA caused two). EG caused by MRSA with concurrent bacteremia can be fatal, especially in patients with hematological malignancies. Although S. aureus-associated EG in patients with hematological malignancies is relatively uncommon, tissue cultures with an initial gram stain smear are essential for selecting appropriate empirical antimicrobials, including the coverage of S. aureus.

Streptococcus gallolyticus subspecies pasteurianus bacteremia accompanied by acute pancreatitis.

INTRODUCTION: While Streptococcus gallolyticus subsp. gallolyticus has a well-known association with colorectal cancer, an epidemiological association between S. gallolyticus subsp. pasteurianus (SGSP) and hepatobiliary diseases has been suggested. Here we described a case of gallstone pancreatitis and SGSP bacteremia in which species-identification by Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) helped to diagnose the biliary etiology. CASE REPORT: A 61-year-old Japanese man without history of alcohol consumption was hospitalized for acute pancreatitis. His past medical history included endoscopically treated familial adenomatous polyposis. A blood culture grew gram-positive cocci, identified to be SGSP by MALDI-TOF MS. A contrast-enhanced computed tomography scan showed pancreatic enlargement and increased fatty tissue concentration around the perirenal and pararenal space. He was diagnosed with acute pancreatitis and subsequently recovered after appropriate antimicrobial therapy and supportive care. Subsequent magnetic resonance cholangiopancreatography showed gallstones in the gallbladder neck, suggesting the cause of the acute pancreatitis. Seven months after admission, cholecystectomy was performed for cholelithiasis. CONCLUSION: This case highlights that the identification of subspecies enabled by MALDI-TOF MS supports the diagnosis of the underlying etiology from the microbiological point of view.

Impact of antibiotic timing relative to percutaneous aspiration on culture positivity rate and clinical outcomes: A retrospective study of patients with pyogenic liver abscess.

The optimal timing of antibiotic administration relative to liver abscess aspiration is debatable. This retrospective cohort study investigated whether the timing affects the abscess culture positivity rate and clinical outcomes. Twenty-nine patients with 30 percutaneously drained liver abscess cases were analyzed. Antibiotics were administered before aspiration (pre-aspiration antibiotics) in 22 cases and following aspiration (post-aspiration antibiotics) in 8 cases (i.e., 1 patient underwent aspiration twice, both before and following antibiotics). Both groups demonstrated similar patient characteristics, short time to aspiration, and high antibiotic appropriateness. Most patients were immunocompetent and non-septic. Pre-aspiration antibiotics did not reduce the culture yield (95% with pre-aspiration antibiotics vs. 100% with post-aspiration antibiotics; p = 1). Post-aspiration antibiotics were not associated with higher mortality, longer length of hospitalization, or an increased rate of clinical deterioration following aspiration. With appropriate antibiotic and aspiration, antibiotics timing can be either before or after aspiration without compromising the culture positivity rate and clinical outcomes.

Current antimicrobial prescription at outpatient dentistry centers and clinics in tertiary-care hospitals in Tokyo, Japan: A multicenter cross-sectional study.

Background: Antimicrobial administration is necessary before specific dental procedures to prevent postprocedural infections and complications and antimicrobials are sometimes indicated for the treatment of odontogenic infections. However, antimicrobials are commonly misused by dentists. Methods: This cross-sectional study was conducted at 4 public, tertiary-care hospitals in Tokyo, Japan, from June to July 2019. We included patients who received an antimicrobial prescription at the outpatient dentistry center or clinic at each participating hospital. The indications for antimicrobial prescription were (1) antimicrobial prescriptions for prophylaxis (APPs) or (2) antimicrobial prescriptions for treatment (APTs). Prescribing patterns were described in terms of antimicrobial choice, timing, and dosages for APPs and APTs. Results: During the study period, 1,772 patients received an antimicrobial prescription. Among them 1,439 (81.2%) were APPs and 333 (18.8%) were APTs. The most common aim of APP was to prevent local infections and complications following tooth extraction (n = 1,244, 86.4%). The proportion of appropriate APPs was only 0.8% (12 of 1,439). Among 1,439 total APPs, 171 (11.9%) were unnecessary, 32 (2.2%) were inappropriate, and 1,224 (85.1%) were suboptimal. Whereas 101 (30.3%) of 333 APTs were appropriate, the remaining 97 instances (29.1%) were unnecessary, 86 (26.7%) were inappropriate, and 46 (13.8%) were suboptimal. Conclusion: Inappropriate antimicrobial prescriptions were common among dentists in Japan. Understanding the differences in the current antimicrobial prescribing patterns for prophylaxis and treatment is critically important for implementing an effective antimicrobial stewardship program in dentistry.

Nontuberculous mycobacterial bloodstream infections after allogeneic hematopoietic stem cell transplantation.

Non-tuberculous mycobacteria (NTM) bacteremia following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is rare, and limited data exist. We described the features of NTM bacteremia following allo-HSCT recipients in our hospital with a comprehensive review of the literature. Among the four cases of NTM bacteremia after allo-HSCT recipients in our hospital, two were catheter-related bloodstream infections (CRBSI), one was disseminated, and one was an unknown source of infection. Based on our report and the past literature, the incidence rate of NTM bacteremia was 0.1-1.3%. CRBSI (57%) was more common than disseminated infection (29%). Most cases with CRBSI were caused by rapidly growing mycobacteria (88%) and showed good prognoses under appropriate antimicrobial therapies. In contrast, slowly growing mycobacteria (71%) was more common than rapidly growing mycobacteria in disseminated NTM bacteremia. Although disseminated NTM bacteremia can remain stable with appropriate long-term management, three out of seven cases died of multi-organ failure. Background immunodeficiency after allo-HSCT and transplant-related comorbidities may be attributable to subsequent poor prognosis.