Rapid screening of positive blood cultures for extended-spectrum ß-lactamases and metallo-ß-lactamases using a drug susceptibility testing microfluidic method.

OBJECTIVES: An increasing number of drug-resistant bacteria have been identified recently. In particular, drug-resistant bacteria have been linked to unfavorable prognoses in patients with bacteremia, highlighting the need for rapid testing. Our previous studies have focused on the utility of a drug susceptibility testing microfluidic (DSTM) method using microfluidic channels. A system with this DSTM method for screening for ß-lactamases can rapidly detect extended-spectrum ß-lactamases (ESBLs) and metallo-ß-lactamases (MBLs). In this study, we have evaluated the clinical utility of pre-treatment for screening positive blood cultures using the DSTM method. METHODS: A total of 178 positive blood cultures and five simulated samples of MBL-producing bacteria were prepared at Kochi University Hospital, Japan. The pretreatment consisted of a two-step centrifugation. The obtained sediments were screened with the DSTM method for the production of ß-lactamase based on morphological changes in the bacteria after 3 h of incubation. RESULTS: The pretreatment functioned properly for all samples. Of the 25 ESBL samples, 21 were positive for ESBLs. Four false-negative samples, all obtained from the same patient, contained CTX-M-2 enzyme-producing Proteus mirabilis and showed insusceptibility to an ESBL inhibitor. The simulated samples prepared for MBL screening were positive for MBLs. CONCLUSIONS: When combined with a method for rapidly identifying bacterial species, DSTM may enable patients with bloodstream infections to start receiving appropriate treatment within 4 h after positive blood cultures are screened.

Unveiling the role of preceding seasonal influenza in the development of bacteremic pneumococcal pneumonia in older adults before the COVID-19 pandemic in Japan.

OBJECTIVE: We aimed to investigate the impact of preceding seasonal influenza on the clinical characteristics of adult patients with invasive pneumococcal disease (IPD) in Japan. METHODS: Data for 1722 adult patients with IPD were analyzed before (2017-2019) and during the COVID-19 pandemic (2020-2022). RESULTS: The seasonal influenza epidemic disappeared soon after the emergence of the pandemic. Compared with that before the pandemic (66.7%), we observed a lower bacteremic pneumonia proportion in patients with IPD during the pandemic (55.6%). The clinical presentations of IPD cases significantly differed between those with and without preceding influenza. The proportion of bacteremic pneumonia was higher in IPD patients with preceding influenza than in those without in both younger (44.9% vs 84.2%) and older adults (65.5% vs 87.0%) before the pandemic. The case fatality rate was significantly higher in IPD patients with preceding influenza (28.3%) than in those without (15.3%) in older adults before the pandemic (P = 0.020). Male and aging are high risk factors for death in older patients with IPD who had preceding influenza. CONCLUSION: Our study reveals that preceding seasonal influenza plays a role in the development of bacteremic pneumococcal pneumonia, increasing the risk of death in older adults.

Clinical evaluation of a modified SARS-CoV-2 rapid molecular assay, ID NOW ™ COVID-19 2.0.

In the diagnosis of coronavirus disease 2019 (COVID-19), several types of instruments and reagents for SARS-CoV-2 nucleic acid testing have been introduced to meet clinical needs. We evaluated the clinical performances of ID NOW™ COVID-19 2.0 (ID NOW™ 2.0), which is capable of detecting SARS-CoV-2 within 12 min as part of point-of-care testing (POCT). Patients who displayed COVID-19 related symptoms, and who were tested for screening purposes, were recruited to this study. Two nasopharyngeal swabs were collected and tested using the ID NOW™ 2.0 test. Reference testing was performed using the cobas 8800 or 6800 (reagents: cobas SARS-CoV-2 and Flu A/B). A total of 38 samples and 46 samples were tested positive and negative, respectively, by the reference test. The ID NOW™ 2.0 showed a sensitivity of 94.7% (95% CI: 82.3-99.4) and a specificity of 100% (95% CI: 92.3-100). Samples that were positive by reference testing had cycle threshold (Ct) values ranging from 11.90 to 35.41. Among these reference positive samples, two samples were negative by ID NOW™ 2.0 with Ct values of 35.25 and 35.41. For samples with Ct values < 35, the sensitivity of ID NOW™ 2.0 was 100%. In Japan, the restrictions related to COVID-19 have been relaxed, however the COVID-19 epidemic still continues. ID NOW™ 2.0 is expected to be used as a rapid and reliable alternative to laboratory-based RT-PCR methods.

Distinguishing sterile inflammation from graft infection.

We describe the case of a 68-year-old man who underwent ascending aortic replacement and thoracic endovascular aortic repair. Four years later, the patient developed neck pain on the right side and chest computed tomography showed expansion of fluid in the mediastinum which had extended to the neck. Echocardiography revealed advanced severity of aortic regurgitation and decreased ejection fraction. Given the progression of aortic regurgitation, decreased cardiac function, and rapidly expanding fluid accumulation causing neck pain, reoperation was indicated. All microbiological test including polymerase chain reaction were negative indicating absence of any infection. The patient is being followed-up without antibiotics and CT has not shown peri-graft fluid 2 years postoperatively. Since infection cannot be excluded completely, it is important to assess the condition with selective medium, extended culture periods, genetic testing, and consultations with microbiology laboratories when normal culture tests for general bacteria, and fungi are negative which can help avoid drug-resistant bacteria count, elevated medical costs, and drug side effects due to the improper use of antibiotics through proper diagnosis.

Unilateral lymphadenitis caused by community-associated methicillin-resistant Staphylococcus aureus ST834 strain.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a global concern, primarily as a cause of skin and soft tissue infections, particularly in young people. Here, we describe a case of unilateral multiple lymphadenitis caused by the CA-MRSA sequence type (ST) 834 strain. A previously healthy 15-year-old girl was referred to our hospital with fever and swollen lymph nodes in the right axillary, cubital, and groin regions. Imaging examinations revealed enlargement of the lymph nodes in these areas but no swelling in any other lymph nodes. The patient had self-destructive lymph nodes in her groin. MRSA was detected in all swollen lymph node samples. Antimicrobial susceptibility tests showed that MRSA was susceptible to clindamycin and levofloxacin, leading to the suspicion of CA-MRSA. Genetic analysis revealed that all strains were ST834 and carried the staphylococcal cassette chromosome mec IV and the toxic shock syndrome toxin-1 gene but not the Panton-Valentine leukocidin gene. The patient was treated with linezolid followed by oral clindamycin. This was a rare case of unilateral multiple lymphadenitis caused by ST834 CA-MRSA. Although ST834 strains are rarely reported, lymphadenitis has been frequently reported and is considered more likely to cause lymphadenitis than other CA-MRSA strains.

First case of bacteremia caused by Cetobacterium somerae following necrotizing cholecystitis.

Cetobacterium somerae, a gram-negative anaerobic rod, first identified in the feces of children with autism, also colonize freshwater fish intestinal tract. However there have been no reports of human C. somerae infection. Here, we describe the first case of C. somerae bacteremia in a patient with necrotizing cholecystitis. A 72-year-old male presented to the emergency department with chills, vomiting, and fever and was diagnosed with acute necrotizing cholecystitis. An emergency cholecystectomy was performed and the following day, two sets of blood culture were positive for gram-negative bacilli. Identification of C. somerae from the biochemical profile was difficult but possible by mass spectrometry and 16s rRNA sequence.

COVID-19 Cluster in the Hematology/Respirology Ward of a University Hospital during the Seventh Wave of the SARS-CoV-2 Pandemic in Japan: A Descriptive Study.

Objective Patients with hematological malignancies and solid organ tumors reportedly tend to have a more severe coronavirus disease 2019 (COVID-19) trajectory than do those with other diseases. We studied the clinical features and outcomes of nosocomial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the seventh wave of the pandemic. Methods This study retrospectively described the characteristics of COVID-19 clusters involving patients in the hematology/respirology ward of Kochi Medical School Hospital during the seventh wave of the pandemic of SARS-CoV-2. Patients A total of 40 individuals, including 25 patients and 15 healthcare workers, were studied. The diagnosis of SARS-CoV-2 infection was based on reverse transcription polymerase chain reaction performed on nasopharyngeal samples. Results Eleven patients had hematological diseases, and 14 had respiratory diseases. Most patients presented with a fever (n=19) and/or sore throat (n=10). Lower respiratory tract symptoms and pneumonia were rather infrequent, occurring in two patients. All patients received antivirals. The maximal severities were mild in 21 patients and moderate in 2. Two asymptomatic patients with SARS-CoV-2 infection did not develop symptoms of COVID-19. Cycle threshold values in nasopharyngeal samples were significantly lower in patients with COVID-19 than in those who were asymptomatic at the time of the diagnosis with SARS-CoV-2 infection. All SARS-CoV-2-infected inpatients recovered or did not develop symptoms of COVID-19. Conclusion COVID-19 vaccination, early or preemptive treatment with antivirals, and intrinsic changes in SARS-CoV-2 may have contributed to the more favorable outcomes in our series than in previously reported nosocomial clusters.

Psoas and Mediastinal Abscesses during Intravenous Tocilizumab Treatment in Multicentric Castleman Disease.

Tocilizumab has been used to treat idiopathic multicentric Castleman disease (iMCD). As tocilizumab prevents interleukin-6 from exerting pro-inflammatory effects, there is some concern about a delayed diagnosis of severe infections during tocilizumab treatment. Although serious infections during tocilizumab therapy have been previously described in patients with rheumatoid arthritis, they have not been reported in iMCD. We herein report a case of disseminated Staphylococcus aureus infection after a superficial skin wound followed by psoas and mediastinal abscesses with pyogenic spondylodiscitis in an iMCD patient with diabetes. Physicians should be alert for the occurrence of disseminated S. aureus infection after even minor skin injury during tocilizumab therapy.

Serum Cytokine Profiles of Rapid Recovery Patients with COVID-19: Series of 6 Cases.

COVID-19 patients reveal various clinical manifestations; however, the specific mechanisms and factors contributing to rapid recovery remain unclear. We performed serum cytokine profiling using a bead-based immunoassay in six COVID-19 patients with mild symptoms who experienced rapid recovery. All patients had fever that resolved within 4 days. During the study, the interferon gamma-related protein 10 (IP-10) level rapidly increased initially, and then rapidly decreased in all six patients. Similarly, the interferon (IFN)-λ 2/3 levels rapidly increased initially, and then decreased in five of the six patients. IP-10 and IFN-λ2/3 may play a key role in the rapid recovery of mild COVID-19.

Massive surge of mRNA expression of clonal B-cell receptor in patients with COVID-19.

BACKGROUND: Antibody production is one of the primary mechanisms for recovery from coronavirus disease 2019 (COVID-19). It is speculated that massive clonal expansion of B cells, which can produce clinically meaningful neutralizing antibodies, occurs in patients who recover on the timing of acquiring adaptive immunity. METHODS: To evaluate fluctuations in clonal B cells and the size of the clones, we chronologically assessed the B-cell receptor (BCR) repertoire in three patients with COVID-19 who recovered around 10 days after symptom onset. RESULTS: We focused on the three dominant clonotypes (top 3) in each individual. The percentage frequencies of the top 3 clonotypes increased rapidly and accounted for 27.8 % on day 9 in patient 1, 10.4 % on day 12 in patient 2, and 10.8 % on day 11 in patient 3, respectively. The frequencies of these top 3 clonotypes rapidly decreased as the patients' clinical symptoms improved. Furthermore, BCR network analysis revealed that accumulation of clusters composed of similar complementarity-determining region 3 (CDR3) sequences were rapidly formed, grew, and reached their maximum size around 10 days after symptom onset. CONCLUSIONS: BCR repertoire analysis revealed that a massive surge of some unique BCRs occurs during the acquisition of adaptive immunity and recovery. The peaks were more prominent than expected. These results provide insight into the important role of BCRs in the recovery from COVID-19 and raise the possibility of developing neutralizing antibodies as COVID-19 immunotherapy.

Impact of Infectious Disease Consultation on Management and Outcomes of Infective Endocarditis.

BACKGROUND: Infective endocarditis (IE) is associated with significant morbidity and mortality, and successful management requires expertise in both cardiac surgery and infectious disease (ID). However, the impact of ID consultation on the clinical outcomes of IE is not clear. METHODS: The present study was a quasi-experimental, interrupted time series analysis of the clinical outcomes of patients with IE before (April 1998-April 2008) and after (May 2008-March 2019) the establishment of an ID department at a tertiary care hospital in Japan. The primary outcome was clinical failure within 90 days, defined as a composite of all-cause mortality, unplanned cardiac operation, new-onset embolic events, and relapse of bacteremia caused by the original pathogen. RESULTS: Of 238 IE patients, 59 (25%) were treated in the preintervention period, and 179 (75%) were treated in the postintervention period. Establishment of an ID department was associated with a 54% reduction in clinical failure (relative risk, 0.46; 95% confidence interval, 0.21-1.02; P = .054) and a 79% reduction in new-onset embolic events (relative risk, 0.21; 95% confidence interval, 0.07-0.71; P = .01). In addition, the rate of inappropriate IE management significantly decreased (relative risk, 0.06; 95% confidence interval, 0.02-0.22; P < .01). CONCLUSIONS: Establishment of an ID department at a tertiary care hospital was associated with improved management, better clinical outcomes, and reduced embolic events in patients with IE admitted to the hospital.

Young adult onset systemic Epstein-Barr virus-positive T-cell lymphoproliferative disorders of childhood.

A 20-year-old woman had a fever, pancytopenia, and liver failure, and was suspected to be suffering from chronic active Epstein-Barr virus (EBV) infection, based on the detection of high EBV-DNA and EBV antibody titers at another hospital. At our institution one month later, clinical manifestations had diminished, and antibody titers had decreased but remained elevated relative to normal levels. Four days later, the patient required hospitalization due to fever, liver damage, and cervical lymphadenopathy. Bone marrow examination and lymph node biopsy results showed EBV-positive cytotoxic T-cells that were predominantly CD4-positive. The disease followed a fulminant course and the patient died of multiple organ failure on hospitalization day 11. Because complicated chromosomal aberrations and T-cell receptor gene rearrangements were identified, we diagnosed her as having systemic EBV-positive T-cell lymphoproliferative disorder of childhood. This disease type includes a lymphoproliferative disorder that is associated with chronic active EBV infection. However, it is clinically different from the type following acute EBV infection. We consider distinguishing between these two types to be important for selecting an early diagnostic procedure and the optimal therapy.

Recombinant human soluble thrombomodulin safely and effectively rescues acute promyelocytic leukemia patients from disseminated intravascular coagulation.

We treated individuals for disseminated intravascular coagulation (DIC) caused by acute promyelocytic leukemia (APL) (n=9) using human soluble thrombomodulin (rTM) in combination with all-trans retinoic acid (ATRA) and chemotherapy, and compared the clinical outcomes with historical control patients (n=8) treated with ATRA and/or chemotherapy. Two control patients developed intracranial vascular incidents. On the other hand, no bleeding related mortality was noted in rTM-treated patients. Notably, treatment with rTM rescued patients from DIC earlier than historical controls (log rank test, p=0.019). These results suggest that administration of rTM should be considered for the treatment of individuals with DIC associated with APL.