A case of prosthetic valve endocarditis and aortic abscess due to Bacillus cereus.

Bacillus cereus (B. cereus) is commonly found in the environment and is often considered a blood culture contaminant. However, in patients with specific risk factors such as intravenous drug use, central venous access catheters, immunosuppression, or prosthetic valves, B. cereus can cause severe infections. Herein, we present a case of prosthetic valve endocarditis (PVE) caused by B. cereus in an 84-year-old woman with a history of aortic valve replacement for aortic stenosis five years earlier. She presented with anorexia, and her physical examination revealed tenderness in the left upper quadrant of the abdomen. Blood culture grew B. cereus, and a CT scan showed splenic infarction, raising suspicion of PVE. Transesophageal echocardiogram (TEE) revealed an abscess around the left coronary cusp of the aortic valve and a 15 mm vegetation. Due to the patient's high risk for post-operative complications and her unwillingness to undergo surgery, the surgery was deferred. Instead, she was successfully treated with six weeks of intravenous vancomycin and discharged home. Follow-up TEE demonstrated resolution of the vegetation and valvular abscess. At her six-month post-discharge evaluation, no signs of active infection were noted including fever or worsening heart failure. Although surgery is typically recommended for most cases of PVE, conservative treatment can be considered as an alternative option for selected patients.

Clinical and microbiological characteristics of Ruminococcus gnavus bacteremia and intra-abdominal infection.

OBJECTIVES: Ruminococcus gnavus is a rare human pathogen, and clinical data on R. gnavus infection are insufficient. This retrospective study aimed to investigate the clinical characteristics of R. gnavus infections. METHODS: This study included 13 cases of bacteremia and three cases of non-bacteremia infections caused by R. gnavus. We evaluated the patient data, infection source, clinical outcomes, and antimicrobial susceptibility of R. gnavus isolates for these cases. RESULTS: The median age of patients was 75 years (range 47-95), and eight patients were female. Twelve cases were presumed to have an intra-abdominal infection source, and the remaining four cases had an unknown infection source. The most common underlying conditions were immunosuppression (seven cases), solid tumors (seven cases), and history of gastrointestinal surgery (five cases). Thirteen patients exhibited gastrointestinal problems (dysfunction, bleeding, intra-abdominal infection, or inflammation). Multiple pathogens were observed in six cases, and fatal outcomes were recorded in three cases. Antimicrobial susceptibility data were available for eight isolates, all of which exhibited low minimum inhibitory concentrations to penicillin (≤0.03 µg/mL), ampicillin-sulbactam (≤0.5 µg/mL), piperacillin-tazobactam (≤4 µg/mL), and metronidazole (≤0.5-1 µg/mL). CONCLUSION: Ruminococcus gnavus is frequently associated with an intra-abdominal infection source, and treatment strategies should consider the possibility of multiple pathogens.

Immunogenicity and safety of influenza vaccine in patients with lung cancer receiving immune checkpoint inhibitors: A single-center prospective cohort study.

INTRODUCTION: Patients with lung cancer have a high risk of influenza complications. International guidelines recommend annual influenza vaccination for patients with cancer. Immune checkpoint inhibitors (ICIs) are progressively used to treat lung cancer. Data regarding immunogenicity and safety of influenza vaccine are limited in patients with lung cancer receiving ICIs; therefore, we conducted this single-center, prospective observational study in the Japanese population. METHODS: Patients with lung cancer receiving ICIs and influenza immunization were enrolled. Blood samples were collected from patients for serum antibody titer measurement pre- and 4 ± 1 weeks post-vaccination. The primary endpoint was seroprotection rate (sP) at 4 ± 1 weeks post-vaccination. The secondary endpoints were geometric mean titer (GMT), mean fold rise, seroresponse rate (sR), seroconversion rate (sC), and immune-related adverse events (irAEs), defined as adverse effects caused by ICI administration, 6 months post-vaccination. RESULTS: Influenza vaccination in the 23 patients included in the immunogenicity analyses significantly increased GMT for all strains, and sP, sR, and sC were 52%-91%, 26%-39%, and 26%-35%, respectively. In the 24 patients included in the safety analyses, 7 (29%) and 5 (21%) patients exhibited systemic and local reactions, respectively. Only one patient (4%) (hypothyroidism, grade 2) showed post-vaccination irAEs. CONCLUSIONS: Overall, influenza vaccination in patients with lung cancer receiving ICIs showed acceptable immunogenicity and safety, thus supporting annual influenza vaccination in this population.

Immunogenicity and safety of COVID-19 vaccine in lung cancer patients receiving anticancer treatment: A prospective multicenter cohort study.

This study assessed the immunogenicity and safety of the BNT162b2 mRNA vaccine in lung cancer patients receiving anticancer treatment. We enrolled lung cancer patients receiving anticancer treatment and non-cancer patients; all participants were fully vaccinated with the BNT162b2 vaccine. Blood samples were collected before the first and second vaccinations and 4 ± 1 weeks after the second vaccination. Anti-severe respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein S1 subunit receptor-binding domain antibody titers were measured using the Architect SARS-CoV-2 IgG II Quant and Elecsys Anti-SARS-CoV-2 S assays. Fifty-five lung cancer patients and 38 non-cancer patients were included in the immunogenicity analysis. Lung cancer patients showed significant increase in the geometric mean antibody concentration, which was significantly lower than that in the non-cancer patients after the first (30 vs. 121 AU/mL, p < .001 on Architect; 4.0 vs 1.2 U/mL, p < .001 on Elecsys) and second vaccinations (1632 vs. 3472 AU/mL, p = .005 on Architect; 213 vs 573 A/mL, p = .002 on Elecsys). The adjusted odds ratio (aOR) for seroprotection was significantly lower (p < .05) in lung cancer patients than that in non-cancer patients. Analysis of the anticancer treatment types showed that the aOR for seroprotection was significantly lower (p < .05) in lung cancer patients receiving cytotoxic agents. They showed no increase in adverse reactions. BNT162b2 vaccination in lung cancer patients undergoing anticancer treatment significantly increased (p < .05) antibody titers and showed acceptable safety. Immunogenicity in these patients could be inadequate compared with that in non-cancer patients.

Catheter-related bloodstream Mycobacterium wolinskyi infection in an umbilical cord blood transplant recipient: a case report.

BACKGROUND: Catheter-related bloodstream infection (CRBSI), caused by rapidly growing mycobacteria (RGM), is a rare infectious complication in hematopoietic stem cell transplant (HSCT) recipients and can often be misdiagnosed as Gram-positive rod (GPR) bacteremia. CASE PRESENTATION: We present a case of CRBSI caused by Mycobacterium wolinskyi, a rare RGM, in a 44-year-old female patient who received an umbilical cord blood transplant. CONCLUSIONS: Rapidly growing mycobacteria can stain as GPRs and may grow in routine blood culture media after 3-4 days of incubation. These features are not widely known to clinicians, and acid-fast staining is therefore recommended when unidentifiable GPRs are detected in blood cultures, especially in immunocompromised patients, such as those with hematologic malignancies or intravascular devices.

Efficacy and Safety of Endobronchial Ultrasonography with a Guide-sheath for Acute Pulmonary Lesions in Patients with Haematological Diseases.

Objective Acute pulmonary lesions (APLs), defined as an acute infiltrate or nodular lung field, are a major complication in patients with haematological diseases. Recently, endobronchial ultrasonography with a guide-sheath (EBUS-GS) was established as a useful technique for diagnosing pulmonary lesions. This study aimed to evaluate the efficacy and safety of EBUS-GS for managing APLs in patients with haematological diseases. Methods Our single-centre, retrospective, observational, single-arm, descriptive study enrolled 22 consecutive adult (>20-year-old) patients with haematological diseases and concomitant APL who underwent EBUS-GS between January 2011 and June 2016 at Kameda Medical Center, Chiba, Japan. The primary endpoint was the contribution of EBUS-GS to clinical decision-making. Secondary endpoints were an adequate tissue collection rate, diagnostic yield, complication rate, and 30-day mortality. Results The median patient age was 70 years old, and 63.6% were men. Acute myeloid leukaemia was the most frequent underlying disease, accounting for 54.5% of patients. The contribution of EBUS-GS to clinical decision-making was recognised in 11 (50.0%) patients. Adequate tissue collection was achieved in 21 (95.5%) patients. The aetiology of the APL was identified in 9 (40.9%) patients. No complications, including severe haemorrhaging and pneumothorax, were observed in any patients, and the 30-day mortality rate was 0%. Conclusion EBUS-GS may be a suitable diagnostic option for APL in patients with haematological diseases. Further larger-scale and randomised controlled trials are needed to confirm our results.

Antibody response to COVID-19 vaccination in patients with lymphoma.

Patients with lymphoma are at increased risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); therefore, evaluation of SARS-CoV-2 vaccination efficacy is essential. We conducted a prospective observational study to monitor the antibody response in 500 patients with lymphoma after SARS-CoV-2 vaccination. Antibody levels increased in a stepwise manner after the first and second dose of the vaccine. After completion of the two-dose series, anti-S antibody was negative in 109 patients (21.8%), and below clinically protective levels (anti-S ≥ 264 U/mL) in 236 patients (47.2%). The median anti-S titers at 0-6 months, 7-12 months, 13-24 months, and 24 months after treatment completion were 0.4 U/mL, 3.8 U/mL, 270 U/mL, and 650 U/mL, respectively. Multivariate analysis showed that receiving the vaccine < 6 months since completing treatment, white blood cell count < 5050/µL, percentage of CD19 + cells < 10%, CD4 + cells < 27%, immunoglobulin (Ig) A < 195 mg/dL, IgM < 50 mg/dL, serum soluble interleukin 2 receptor > 600 U/mL, and presence of lymphoma cells in the peripheral blood were significantly correlated with anti-S < 264 U/mL. Lymphoma patients had variably impaired antibody response to the SARS-CoV-2 vaccine. We identified various factors to predict COVID-19 vaccine effectiveness in lymphoma patients that may help tailoring possible vaccine boosters.

Low clinical protective response to SARS-CoV-2 mRNA COVID-19 vaccine in patients with multiple myeloma.

We conducted a prospective, three-center, observational study in Japan to evaluate the prevalence of seropositivity and clinically protective titer after coronavirus disease 2019 vaccination in patients with plasma cell dyscrasia(PCD). Two-hundred sixty-nine patients with PCD [206 symptomatic multiple myeloma (MM)] were evaluated. Seropositivity was observed in 88.7% and a clinically protective titer in 38.3% of MM patients, both of which were significantly lower than those of healthy controls. Patients receiving anti-CD38 antibodies had much lower antibody titers, but antibody titers recovered in those who underwent a wash-out period before vaccine administration. Older age (≥65), anti-CD38 antibody administration, immunomodulatory drugs use, lymphopenia (<1000/µL), and lower polyclonal IgG (<550 mg/dL) had a negative impact for the sufficient antibody production according to multivariate analysis. Patients with clinically protective titer had a significantly higher number of CD19+ lymphocytes than those with lower antibody responses (114 vs. 35/µL, p = 0.016). Our results suggested that patients with PCD should be vaccinated, and that the ideal protocol is to temporarily interrupt anti-CD38 antibody therapy for a "wash-out" period of a few months, followed by a (booster) vaccine after the B-cells have recovery.

A case of Salmonella osteomyelitis mimicking a malignant tumor of the humerus in an immunocompetent adult patient identified using broad-range polymerase chain reaction with sequencing of a biopsied specimen.

BACKGROUND: Salmonella infections are associated with gastroenteritis, enteric fever, bacteremia, focal infection, and chronic carrier state. Cases of Salmonella osteomyelitis are uncommon and mainly occur in individuals with immunosuppressive conditions. Herein, we report a case of Salmonella osteomyelitis that required differentiation from malignancy in an immunocompetent adult patient. CASE PRESENTATION: A 31-year-old previously healthy male truck driver presented with a 2-week history of pain in his left upper arm. He had fallen off the back of a truck 2 months previously and injured the left side of his body. He also had bloody diarrhea and fever. Computed tomography and magnetic resonance imaging revealed a lesion that appeared to be a bone tumor in the left humerus, and the patient was referred to our cancer center from another clinic. Culture of a biopsy specimen of the left humerus was negative; however, the consensus sequence in broad-range polymerase chain reaction (PCR) showed the highest similarity to the 16S rRNA gene of Salmonella enterica subspecies enterica. Curettage of the left humerus was performed, and the patient was administered levofloxacin for 6 weeks. He recovered left arm function and had no recurrence during 2 months of follow-up. CONCLUSIONS: When the culture of blood or biopsy specimens is negative in situations wherein a specific infection is suspected, broad-range PCR with sequencing should be considered to determine the causative organism.

Early diagnosis of Cryptococcus neoformans var. grubii meningitis using multiplex PCR assay in an immunocompetent patient.

Cryptococcosis is an invasive fungal infection that mainly affects the lungs and central nervous system. While patients with cell-mediated immunodeficiency are at high risk of developing cryptococcosis, there have been increasing reports of cryptococcosis in immunocompetent individuals with no underlying conditions. Herein, we report a case of cryptococcal meningitis in a 55-year-old apparently immunocompetent man with a history of heavy alcohol consumption. Although the patient was initially treated for tuberculous meningitis and varicella-zoster virus induced vasculopathy due to a history of exposure to tuberculosis and a presence of stroke, a multiplex polymerase chain reaction (PCR) assay of cerebrospinal fluid (CSF) identified Cryptococcus species unexpectedly, enabling swift treatment and a favorable clinical outcome. The multiplex PCR assay, which can identify multiple pathogens simultaneously and instantly, may lead to early diagnosis and treatment by detecting unanticipated pathogens. Furthermore, the strain was identified through multilocus sequence typing (MLST) analysis as Cryptococcus neoformans var. grubii, Sequence Type 5, molecular type: VNI. Although simplified microbial identification techniques such as mass spectrometry have recently been developed, molecular biological assays are still essential for the accurate identification of infectious strains.

Catheter-related bloodstream infection by Microbacterium paraoxydans in a pediatric patient with B-cell precursor acute lymphocytic leukemia: A case report and review of literature on Microbacterium bacteremia.

Microbacterium species are coryneform gram-positive rods that are widely distributed in the environment and have been recently recognized as rare pathogens in humans. However, information about the epidemiologic and clinical characteristics of Microbacterium species is scarce. We herein reported an 11-year-old girl with acute leukemia who was found to have catheter-related bloodstream infection in her neutropenic phase. Gram-positive bacilli repeatedly grew on the blood cultures and were later confirmed by 16S rRNA analysis as Microbacterium paraoxydans. A literature review found available clinical courses in 21 cases (7 pediatric cases) of Microbacterium spp. bacteremia. Our case and those in literature suggested that Microbacterium spp. bacteremia often occurs in patients with indwelling central venous catheters; the literature review further suggested that removal of central venous catheters is required in most cases and that 16S rRNA sequence was useful in identifying in detail the species of Microbacterium.

Lactococcus lactis cholangitis and bacteremia identified by MALDI-TOF mass spectrometry: A case report and review of the literature on Lactococcus lactis infection.

Lactococcus lactis is a rare causative organism in humans. Cases of L. lactis infection have only rarely been reported. However, because it is often difficult to identify by conventional commercially available methods, its incidence may be underestimated. We herein report the case of a 70-year-old man with cholangiocarcinoma who developed L. lactis cholangitis and review previously reported cases of L. lactis infection. Our case was confirmed by matrix-assisted desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). This case shows L. lactis is a potential causative pathogen of cholangitis and that MALDI-TOF MS can be useful for the rapid and accurate identification of L. lactis infection. We searched the literature for published case reports on cholangitis and any other infections caused by L. lactis, and thereby identified 36 cases, including our case. At least 66.7% (n = 24) of the cases had significant underlying conditions; 15 of the cases involved patients with an immunocompromised status. At least 41.7% (n = 15) had a significant food consumption history, such as the consumption of unpasteurized dairy products. The clinical sources of L. lactis were diverse and endocarditis was the most common diagnosis (n = 8), followed by hepatobiliary infection (n = 6), central nervous system infection (n = 5), and peritonitis (n = 4). The prognosis was favorable in most cases.

Vertebral Osteomyelitis Caused by Helicobacter cinaedi Identified Using Broad-range Polymerase Chain Reaction with Sequencing of the Biopsied Specimen.

A 65-year-old man presented with gradually exacerbating low back pain. Magnetic resonance imaging revealed vertebral osteomyelitis in the Th11-L2 vertebral bodies and discs. The patient showed negative findings on conventional cultures. Direct broad-range polymerase chain reaction (PCR) with sequencing of the biopsied specimen had the highest similarity to the 16S rRNA gene of Helicobacter cinaedi. This case suggests that direct broad-range PCR with sequencing should be considered when conventional cultures cannot identify the causative organism of vertebral osteomyelitis, and that this method may be particularly useful when the pathogen is a fastidious organism, such as H. cinaedi.

Legionella pneumonia appeared during hospitalization in a patient with hematological malignancy confirmed by sputum culture after negative urine antigen test.

Legionella pneumophila is recognized as a common causative organism for community-acquired pneumonia, but it is rarely a causative organism for hospital-acquired pneumonia, except in cases of hospital outbreak. Recently, most of the Legionella cases have been diagnosed using the urine antigen test. However, this test can reliably detect only L. pneumophila serogroup 1. Here we report a 63-year-old male patient who was recently diagnosed with acute leukemia and treated with chemotherapy and who developed pneumonia on hospital day 8 during the nadir phase. He was later diagnosed with Legionella pneumonia by culture despite a negative urine antigen test. This case suggests that Legionella pneumonia is an important differential diagnosis for pneumonia in inpatients in the early phase of hospitalization and that when Legionella infection is clinically suspected, culture using selective media or molecular tests should be performed even if the urine antigen test is negative.

Pyelonephritis with bacteremia caused by Listeria monocytogenes: A case report.

Listeria monocytogenes is a well-known cause of meningitis, colitis, and bacteremia; however, obstructive pyelonephritis caused by L. monocytogenes has never been reported. We herein report on a 90-year-old Japanese woman with obstructive pyelonephritis and bacteremia due to uterus carcinoma invading the ureter. She was admitted to our hospital complaining of fever and chills, and her physical examination revealed left costovertebral angle tenderness. Computed tomography showed hydronephrosis and complete ureteral obstruction due to tumor invasion. Blood and urine cultures upon nephrostomy revealed the growth of L. monocytogenes. We treated the patient with two weeks of intravenous ampicillin and an additional one-week treatment of oral sulfamethoxazole/trimethoprim. This case shows the importance to recognize L. monocytogenes as a potential causative agent of urinary tract infection.

Immunogenicity of trivalent influenza vaccine in patients with lung cancer undergoing anticancer chemotherapy.

Lung cancer is a leading cause of cancer-related death, and patients with lung cancer are a priority group for influenza vaccination. However, few studies have assessed the immunogenicity of the influenza vaccine in these patients. Here, we performed a prospective study to evaluate the immunogenicity of the influenza vaccine in patients with lung cancer undergoing anticancer chemotherapy. Twenty-five patients with lung cancer undergoing anticancer chemotherapy and 26 patients with chronic obstructive pulmonary disease (COPD) as controls were enrolled. A trivalent influenza vaccine containing inactivated A/California/7/2009 (H1N1) pdm09, A/Texas/50/2012 (H3N2), and B/Massachusetts/2/2012 was administered as a single subcutaneous injection. Serum samples were collected before vaccination, and at 4-6 weeks after vaccination. Levels of serum antibody to hemagglutinin were measured. Among patients with lung cancer, the seroprotection rate (postvaccination titer > 1:40) was 84% for both A(H1N1) and A(H3N2), similar to the levels observed in patients with COPD. However, the seroprotection rate for the B strain was significantly lower in patients with lung cancer than in patients with COPD (64% versus 92%). Even after adjustment for potential confounders, patients with lung cancer had a significantly lower odds ratio for seroprotection against the B strain than patients with COPD. Moreover, in patients with lung cancer, those receiving the platinum doublet treatment tended to exhibit a lower seroprotection rate than those receiving a single agent. Thus, patients with lung cancer undergoing anticancer chemotherapy showed acceptable immune responses to a trivalent influenza vaccine, supporting the recommendation for annual influenza vaccination in these patients.

Bloodstream infections caused by Streptococcus anginosus group bacteria: A retrospective analysis of 78 cases at a Japanese tertiary hospital.

OBJECTIVES: To investigate the characteristics of Streptococcus anginosus group (SAG) bacteremia in recent years, we conducted a retrospective cohort study and compared its findings with the data from previous studies. METHODS: All patients with positive blood cultures from May 2005 to September 2014 in a tertiary care center with 925 beds were included. RESULTS: There were 78 cases of SAG bacteremia (51 cases men; median age, 68 years) during the study period. The most common comorbidities were solid tumors in 32.1% of the patients. The most common infection source was hepatobiliary in one-third of all cases. Other infection sites included the following: intra-abdominal (12.8%), thoracic (10.3%), musculoskeletal (9%), urinary tract (7.7%), soft tissues (7.7%), and cervicofacial (6.4%). Susceptibility to penicillin, clindamycin and erythromycin were 100% (78/78), 95% (70/74) and 85% (39/46), respectively. Surgery along with systemic antibiotic treatment was administered in 53% of the cases. In-hospital mortality was 14.1%. CONCLUSION: The clinical sources of the SAG bacteria were diverse, and hepatobiliary infection was the most common source of infection. In more than half of the patients, surgical treatment was performed. Susceptibility to penicillin was 100%, but susceptibility to erythromycin was lower than that reported in previous studies.

Cytomegalovirus Colitis in a Critically Ill Patient Following Severe Legionella Pneumonia with Multiple Organ Failure.

A 68-year-old man visited an emergency department complaining of dyspnea. He was diagnosed to have Legionella pneumonia with multiple organ failure. Although his multiple organ failure improved, he suffered from persistent abdominal pain and diarrhea with continuous minor bleeding. Colonoscopy revealed a longitudinal ulcer of the rectum, below the peritoneal reflection. He was diagnosed with cytomegalovirus (CMV) colitis. Antiviral therapy with ganciclovir was initiated. He finally underwent a colostomy after a bowel stricture caused an intestinal outlet obstruction, which made oral intake impossible. Based on the present case, we believe that CMV colitis must be considered as one of the differential diagnoses when critically ill patients develop continuous diarrhea and abdominal pain.