Thyroid abscess associated with thyrotoxicosis caused by Yersinia enterocolitica subsp. palearctica in a patient with follicular adenoma of the thyroid gland.

BACKGROUND: Yersinia enterocolitica is a gram-negative zoonotic bacterial pathogen that is typically transmitted via the fecal-oral route. The most common clinical manifestation of a Y. enterocolitica infection is self-limited gastroenteritis. Although various extraintestinal manifestations of Y. enterocolitica infection have been reported, there are no reports of thyroid abscesses. CASE PRESENTATION: An 89-year-old Japanese man with follicular adenoma of the left thyroid gland was admitted to our hospital with a 2-day history of fever and left neck pain. Laboratory tests revealed low levels of thyroid stimulating hormone and elevated levels of free thyroxine 4. Contrast-enhanced computed tomography showed low-attenuation areas with peripheral enhancement in the left thyroid gland. He was diagnosed with thyroid abscess and thyrotoxicosis, and treatment with intravenous piperacillin-tazobactam was initiated after collecting blood, drainage fluid, and stool samples. The isolated Gram-negative rod bacteria from blood and drainage fluid cultures was confirmed to be Y. enterocolitica. He was diagnosed with thyroid abscess and thyrotoxicosis due to be Y. enterocolitica subsp. palearctica. The piperacillin-tazobactam was replaced with levofloxacin. CONCLUSION: We report a novel case of a thyroid abscess associated with thyrotoxicosis caused by Y. enterocolitica subsp. palearctica in a patient with a follicular thyroid adenoma.

Risk Factors for Teicoplanin-Associated Acute Kidney Injury in Patients with Hematological Malignancies: Focusing on Concomitant Use of Tazobactam/Piperacillin.

Patients with hematological malignancies (HM) often receive tazobactam/piperacillin (TAZ/PIPC) and glycopeptide antibiotics for febrile neutropenia. The effect of concomitant use of TAZ/PIPC on risk of teicoplanin (TEIC)-associated acute kidney injury (AKI) remains unclear. We investigated the impact of concomitant TAZ/PIPC use on TEIC-associated AKI in HM patients and identified the risk factors. In this retrospective, single-center, observational cohort study, 203 patients received TEIC, 176 of whom satisfied the selection criteria and were divided into TEIC cohort (no TAZ/PIPC; n = 118) and TEIC + TAZ/PIPC cohort (n = 58). AKI was defined as serum creatinine increase ≥0.3 mg/dL within 48 h or ≥50% from baseline. Incidence of AKI in TEIC cohort before and after propensity score matching was 9.3 and 5.9%, respectively, and that in TEIC + TAZ/PIPC cohort was 10.3 and 11.8%. AKI incidence and risk were not significantly different between two cohorts before (p = 0.829; odds ratio (OR) 1.122, 95% confidence interval (CI) 0.393-3.202) and after matching (p = 0.244; OR 2.133, 95% CI 0.503-9.043). Logistic regression analysis with factors clinically or mechanistically potentially related to TEIC-associated AKI, including concomitant TAZ/PIPC use, as independent variables identified baseline hemoglobin level as the only significant risk factor for TEIC-associated AKI (p = 0.011; OR 0.484, 95% CI 0.276-0.848). In HM patients treated with TEIC, concomitant TAZ/PIPC use did not increase AKI risk whereas lower hemoglobin levels had higher risk for TEIC-associated AKI development, suggesting the necessity to monitor serum creatinine when using TEIC in patients with anemia.

Factors associated with changes in activities of daily living from admission to discharge among older patients with pneumonia.

INTRODUCTION: It has not been fully elucidated that nutritional parameters affect the change of activities of daily living (ADL) during pneumonia treatment. This study assessed the impact of nutritional status, including erector spinae muscle (ESM) size on ADL changes from admission to discharge among older patients with community-acquired pneumonia (CAP). METHODS: We retrospectively included patients (age: ≥65 years) who were admitted to the hospital for CAP and underwent chest computed tomography (CT) on admission. ADL was evaluated using the Barthel index, and patients were divided into the maintained or improved ADL group and the declined ADL group from admission through discharge. The ESM cross-sectional area was measured on a single-slice CT image. Logistic regression models were applied for assessing factors associated with changes in ADL. RESULTS: A total of 523 patients hospitalized for CAP (median age 86 years) were evaluated. The declined group had significantly higher ADL levels on admission, a greater frequency of smoking history and malignancy, and a lower frequency of cerebrovascular disease and dementia. No significant difference in ESM size was observed between the groups. Multivariate analysis revealed that higher ADL levels on admission (odds ratio 1.034, interquartile range 1.026-1.043) and malignancy (3.002, 1.150-7.836) were associated with a decline in ADL, whereas cerebrovascular disease (0.579, 0.373-0.900) was related to improvement or maintenance of ADL. CONCLUSIONS: Although nutritional status might not affect the change of ADL among older patients hospitalized with pneumonia, a cerebrovascular disease history may be a good predictor for ADL improvement.

Validity of reducing blood culture incubation time for the BD BACTEC FX blood culture system considering microbiological and clinical aspects.

INTRODUCTION: A blood culture (BC) test is vital for diagnosing bacteremia in clinical practice. Although incubation time varies among automated BC systems, 4-5 days is deemed to be sufficient time for the BD BACTEC FX blood culture system. This study compared the clinical and microbiological characteristics of true-positive BC samples on day 5 with those within 4 days to reduce missed true bacteremia cases. METHODS: We conducted a retrospective study of blood cultures from hospitalized patients between April 2020 and April 2023 at a tertiary care hospital in Japan. RESULTS: In total, 12,342 BC sets were collected from 6,567 patients. Gram-positive bacilli other than Bacillus spp. and Corynebacterium spp., non-albicans Candida, and yeasts other than Candida spp. were detected more frequently in BC-positive patients on day 5 than in those within 4 days. The gastrointestinal tract was the portal of entry more frequently on day 5 than within 4 days (25 % vs. 4 %, p = 0.006). CONCLUSION: A 4-day incubation period is sufficient for the BD BACTEC FX blood culture system under routine conditions. However, a 5-day incubation period may be warranted when low pathogenicity is suspected or the gastrointestinal tract is suspected as the portal of entry.

Seroprevalence kinetics of SARS-CoV-2 antibodies in pediatric patients visiting a hospital during COVID-19 pandemic in Japan.

Children infected with SARS-CoV-2 are often asymptomatic or have mild symptoms. The studies on the seroprevalence kinetics of SARS-CoV-2 antibodies in children are limited. We conducted a cross-sectional survey of the positive rate of the SARS-CoV-2 IgG in pediatric patients without suspected COVID-19 infection between January 2007 and March 2022. We defined the serum samples from the pre-pandemic and pandemic groups (1st-6th waves). Totally, 2557 samples were collected and no samples from the pre-pandemic group or the 1st-4th waves were positive for IgG. There were 4/661 and 16/373 positives at the 5th and 6th waves, respectively. At the 5th wave, the prevalence of IgG was 1.3% in children aged 1-4 years. At the 6th wave, in children <1 year of age, the prevalence was 4.0%, and 2.4%, 5.3%, 5.2% and 10% in age groups 1-4, 5-9, 10-14 and 15-18 years, respectively. In conclusions, the pre-pandemic samples were negative, and the IgG positivity increased during the later period of the pandemic.

Antibody Avidity Maturation Following Recovery From Infection or the Booster Vaccination Grants Breadth of SARS-CoV-2 Neutralizing Capacity.

BACKGROUND: Cross-neutralizing capacity of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants is important in mitigating (re-)exposures. Role of antibody maturation, the process whereby selection of higher affinity antibodies augments host immunity, to determine SARS-CoV-2 neutralizing capacity was investigated. METHODS: Sera from SARS-CoV-2 convalescents at 2, 6, or 10 months postrecovery, and BNT162b2 vaccine recipients at 3 or 25 weeks postvaccination, were analyzed. Anti-spike IgG avidity was measured in urea-treated ELISAs. Neutralizing capacity was assessed by surrogate neutralization assays. Fold change between variant and wild-type neutralization inferred the breadth of neutralizing capacity. RESULTS: Compared with early-convalescent, avidity indices of late-convalescent sera were significantly higher (median, 37.7 [interquartile range 28.4-45.1] vs 64.9 [57.5-71.5], P < .0001). Urea-resistant, high-avidity IgG best predicted neutralizing capacity (Spearman r = 0.49 vs 0.67 [wild-type]; 0.18-0.52 vs 0.48-0.83 [variants]). Higher-avidity convalescent sera better cross-neutralized SARS-CoV-2 variants (P < .001 [Alpha]; P < .01 [Delta and Omicron]). Vaccinees only experienced meaningful avidity maturation following the booster dose, exhibiting rather limited cross-neutralizing capacity at week 25. CONCLUSIONS: Avidity maturation was progressive beyond acute recovery from infection, or became apparent after the booster vaccine dose, granting broader anti-SARS-CoV-2 neutralizing capacity. Understanding the maturation kinetics of the 2 building blocks of anti-SARS-CoV-2 humoral immunity is crucial.

Bacillus subtilis Bacteremia from Gastrointestinal Perforation after Natto Ingestion, Japan.

We report a case of Bacillus subtilis variant natto bacteremia from a gastrointestinal perforation in a patient who ingested natto. Genotypic methods showed the bacteria in a blood sample and the ingested natto were the same strains. Older or immunocompromised patients could be at risk for bacteremia from ingesting natto.

Comparison of Incidence of Hyponatremia between Linezolid and Vancomycin by Propensity Score Matching Analysis.

Several cases of severe hyponatremia induced by linezolid (LZD) were reported. However, severe infections could also cause hyponatremia by increasing vasopressin secretion. To prove that hyponatremia is associated with LZD rather than infection, we compared the incidence and risk of developing hyponatremia between patients receiving LZD and those receiving vancomycin (VCM). A retrospective, single-center, observational cohort study was conducted in patients aged 18 years or older who received intravenous LZD or VCM for 7 d or longer. Hyponatremia was defined as serum sodium level lower than 134 mEq/L and more than 5% decrease from baseline after treatment initiation. The incidence and risk of developing hyponatremia were analyzed between LZD and VCM groups using chi-square test. Four hundred and fifty patients who satisfied the selection criteria were divided into LZD (n = 97) and VCM groups (n = 353). Significant differences in patient characteristics between LZD and VCM groups were observed before propensity score matching, but no significant differences were found after matching. LZD group showed a significantly higher incidence and risk of developing hyponatremia compared to VCM group both before (LZD: 16.5%, VCM: 5.4%; p < 0.001, odds ratio 3.472 [95% confidence interval (CI) 1.711-7.048]) and after (LZD: 17.8%, VCM: 5.5%; p = 0.020, odds ratio 3.738 [95% CI 1.157-12.076]) propensity score matching. In conclusion, propensity score analyses suggest that the risk of hyponatremia associated with LZD is approximately 3.7-fold higher than that associated with VCM, regardless of patient background.

Prevalence of antimicrobial resistant genes in Bacteroides spp. isolated in Oita Prefecture, Japan.

INTRODUCTION: Bacteroides spp. are the most common anaerobic bacteria isolated from the human gastrointestinal tract. Several resistant genes are present in Bacteroides spp. However, most studies have focused on the prevalence of the cfiA gene in Bacteroides fragilis alone. We assessed the susceptibility to antimicrobial agents and the prevalence of cepA, cfiA, cfxA, ermF, nim, and tetQ genes in Bacteroides strains isolated from clinical specimens in our hospital. METHODS: We isolated 86 B. fragilis and 58 non-fragilis Bacteroides strains from human clinical specimens collected from January 2011 to November 2021. Resistance against piperacillin (PIPC), cefotaxime (CTX), cefepime (CFPM), meropenem (MEPM), clindamycin, and minocycline was determined. RESULTS: The resistant rates of penicillins and cephalosporins in non-fragilis isolates were significantly higher than those in B. fragilis isolates. In B. fragilis isolates, the resistant rates of PIPC, CTX, and CFPM in cfxA-positive isolates were significantly higher than those in cfxA-negative isolates (71% vs. 16%, 77% vs. 19%, and 77% vs. 30%, respectively). Thirteen B. fragilis isolates harbored the cfiA gene, two of which were resistant to MEPM. Six of the 13 cfiA-positive B. fragilis isolates were heterogeneously resistant to MEPM. CONCLUSION: It is important to evaluate the use of MEPM as empirical therapy for Bacteroides spp. infections, considering the emergence of carbapenem resistance during treatment, existence of MEPM-resistant strains, and heterogeneous resistance.

Impact of Pseudomonas aeruginosa coverage on the prognosis of elderly patients with community-acquired pneumonia.

BACKGROUND: Although the 2019 American Thoracic Society and Infectious Diseases Society of America guidelines for community-acquired pneumonia (CAP) recommend the use of antibiotics with Pseudomonas aeruginosa coverage for patients with prior sputum isolation of P. aeruginosa, further research is needed to confirm its clinical outcomes. This study aimed to assess the impact of the use of antibiotics with P. aeruginosa coverage on mortality in elderly CAP patients with sputum isolation of P. aeruginosa. METHODS: We retrospectively included consecutive elderly patients who were hospitalized for CAP and P. aeruginosa-positive sputum culture. The association between the use of antibiotics with P. aeruginosa coverage and 28-day mortality was assessed based on propensity score to reduce selection bias. RESULTS: A total of 216 patients were included, and 68 (31%) of them were treated with antibiotics with P. aeruginosa coverage. The number of patients treated with antibiotics with P. aeruginosa coverage was significantly higher among nonsurvivors than among survivors. After adjustment using propensity score, the association between the use of antibiotics with P. aeruginosa coverage and the 28-day mortality was found to be statistically nonsignificant (odds ratio 2.182, 95% confidence interval 0.732-6.508, p = 0.162). CONCLUSIONS: The use of antibiotics with P. aeruginosa coverage in elderly CAP patients with sputum isolation of P. aeruginosa did not improve their prognosis. A randomized control study is required to identify cases that should be treated with antibiotics covering P. aeruginosa.

Factors associated with acid-fast bacillus isolation in patients with noncystic fibrosis bronchiectasis: A cross-sectional study.

INTRODUCTION: Acid-fast bacillus (AFB) is a major pathogen that causes noncystic fibrosis bronchiectasis requiring multidrug chemotherapy. Bronchoscopic bronchial wash is performed to determine the causative pathogens of bronchiectasis; but, predictive factors for AFB isolation have not been fully elucidated. This study aimed to determine the factors associated with AFB isolation from bronchial wash samples. METHODS: This was a single-center, cross-sectional study. Patients undergoing bronchoscopic bronchial wash for bronchiectasis were included, whereas those who did not undergo high-resolution computed tomography (HRCT); had acute pneumonia, interstitial lung disease, and a positive polymerase chain reaction result but a negative culture result for AFB; or in whom a guide sheath was used for suspected lung cancer were excluded. Binomial logistic regression was used to analyze the factors associated with a positive culture for AFB. RESULTS: Of the 96 included cases, AFB isolation was observed in the bronchial wash fluid of 26 patients (27%). No smoking history, a positive result for antiglycopeptidolipid (GPL)-core IgA antibody, and the presence of tree-in-bud appearance, multiple granular and nodular images on HRCT were more commonly observed in patients with AFB isolation than in those without. In the multivariate analysis, the tree-in-bud appearance (odds ratio, 4.223; 95% CI, 1.046-17.052) and anti-GPL core IgA antibody (odds ratio, 9.443; 95% CI, 2.206-40.421) were significantly associated with AFB isolation. CONCLUSIONS: The tree-in-bud appearance on HRCT is likely to predict AFB isolation independent of anti-GPL core IgA antibody results. Bronchoscopic bronchial wash should be recommended for bronchiectasis with multiple granulomas on HRCT.

Association of Vancomycin Trough Concentration and Clearance With Febrile Neutropenia in Pediatric Patients.

BACKGROUND: Febrile neutropenia promotes renal drug excretion. Adult and pediatric patients with febrile neutropenia exhibit a lower vancomycin concentration/dose (relative to bodyweight) ratio than those with other infections. In pediatric patients, renal function relative to bodyweight varies depending on age, and vancomycin clearance is age dependent. This study aimed to analyze the effects of febrile neutropenia on the pharmacokinetics of vancomycin in age-stratified pediatric patients. METHODS: This retrospective, single-center, observational cohort study analyzed 112 hospitalized pediatric patients who met the selection criteria and intravenously received vancomycin at the Department of Pediatrics of the Oita University Hospital between April 2011 and October 2019. RESULTS: The febrile neutropenia (n = 46) cohort exhibited a significantly higher estimated glomerular filtration rate than the nonfebrile neutropenia (n = 66) cohort. Compared with those in the nonfebrile neutropenia cohort, the daily vancomycin dose relative to bodyweight and vancomycin clearance were significantly higher, and the vancomycin trough concentration and vancomycin concentration/dose ratio were significantly lower in the febrile neutropenia cohort. In the age groups of 1-6 and 7-12 years, compared with those in the nonfebrile neutropenia cohort, the vancomycin concentration/dose ratio was significantly lower, and vancomycin clearance was significantly higher in the febrile neutropenia cohort. Univariate and multivariate analyses identified febrile neutropenia as the independent factor influencing vancomycin concentration/dose ratio and clearance only in pediatric patients aged 1-6 years. CONCLUSIONS: Increased initial dosage and therapeutic drug monitoring-guided dose optimization are critical for the therapeutic efficacy of vancomycin in pediatric patients with febrile neutropenia, especially in those aged 1-6 years.

Association between sputum conversion and in-hospital mortality in elderly patients with pulmonary tuberculosis: a retrospective study.

BACKGROUND: Non-conversion of sputum culture or smear within 2 months after the start of treatment is a known poor prognostic factor of pulmonary tuberculosis. In elderly patients, sputum conversion may be delayed because of the age-related decline in immune competence. This study aimed to assess how a long interval to sputum conversion predicts in-hospital mortality in elderly patients with pulmonary tuberculosis. METHODS: Consecutive elderly patients (age > 65 years) who were admitted to our institution for bacteriologically confirmed pulmonary tuberculosis were included. The association between sputum conversion within 30, 60, 90, or 120 days from the start of treatment and in-hospital mortality were analyzed by Cox proportional-hazards regression after adjustment for other potential variables. RESULTS: This study included 262 patients, and 74 patients (28%) died during hospitalization. Multivariate analyses showed that sputum non-conversion within 90 days (adjusted hazard ratio 0.424, 95% CI 0.252-0.712, p = 0.001) or 120 days (0.333, 0.195-0.570, p < 0.001) was independently associated with in-hospital mortality, whereas that within 60 days was not (p = 0.890). CONCLUSIONS: In elderly patients with tuberculosis, 2 months may be insufficient when evaluating sputum conversion as a prognostic factor. Sputum non-conversion within 90 days or longer may predict in-hospital mortality more accurately.

Impact of Inflammation on Intra-individual Variation in Trough Voriconazole Concentration in Patients with Hematological Malignancies.

The pharmacokinetics of voriconazole shows large intra-individual and inter-individual variability and is affected by various factors. Recently, inflammation has been focused as a significant factor affecting the variability. This study aimed to compare the influence of C-reactive protein (CRP) and other clinical laboratory parameters on intra-individual variability in trough voriconazole concentration and examine the impact of inflammation in patients with hematological malignancies. We conducted a retrospective, single-center, observational cohort study. Forty-two patients with hematological malignancy who received oral voriconazole for prophylaxis against deep mycosis and underwent multiple measurements of trough plasma voriconazole concentration were recruited. Quantitative changes in pharmacological and clinical laboratory parameters (Δ) were calculated as the difference between the current and preceding measurements. Voriconazole concentration/maintenance dose per weight (C/D) was found to correlate positively with CRP level (n = 202, rs = 0.314, p < 0.001). Furthermore, ΔC/D correlated positively with ΔCRP level (n = 160, rs = 0.442, p < 0.001), and ΔCRP showed the highest correlation coefficient among the laboratory parameters. Univariate and multivariate analyses identified ΔCRP (p < 0.001) and Δgamma-glutamyl transpeptidase (γGTP) (p = 0.019) as independent factors associated with ΔC/D. Partial R2 were 0.315 for ΔCRP and 0.024 for ΔγGTP, suggesting markedly greater contribution of ΔCRP to ΔC/D. In conclusion, since clinical laboratory parameters other than CRP had little influence on trough plasma voriconazole concentration, therapeutic drug monitoring and dose adjustment considering fluctuation in CRP level would be important for proper use of voriconazole in patients with hematological malignancies.

Methicillin-resistant Staphylococcus aureus among elderly patients with community-acquired pneumonia.

INTRODUCTION: The 2019 American Thoracic Society/Infectious Diseases Society of America guidelines for community-acquired pneumonia (CAP) recommend methicillin-resistant Staphylococcus aureus (MRSA) coverage for patients with prior sputum isolation of MRSA. This study aimed to determine the impact of MRSA coverage on in-hospital mortality in elderly patients with CAP among whom MRSA was isolated. METHODS: Consecutive elderly patients who were admitted for CAP and had positive sputum culture for MRSA were retrospectively included, and the association between MRSA coverage and in-hospital mortality was analyzed. RESULTS: Twenty (18%) of 111 patients received MRSA coverage. Although patients who received MRSA coverage tended to have more frequent prior isolation of MRSA compared to those who did not, no significant difference in in-hospital mortality was observed between both groups (2/20, 10% vs. 8/91, 9%). MRSA coverage was not associated with in-hospital mortality (odds ratio: 1.15; 95% CI: 0.23-5.89, p = 0.864); however, advanced age, hemoglobin level, a high A-DROP score, and C-reactive protein levels were associated with in-hospital mortality. MRSA coverage may not improve the prognosis of elderly patients with CAP who had positive sputum culture for MRSA. CONCLUSIONS: A randomized control study is required to determine the efficacy of MRSA coverage on the management of CAP in elderly patients.

Efficacy of extracorporeal membrane oxygenation for acute respiratory failure with interstitial lung disease: a case control nationwide dataset study in Japan.

BACKGROUND: Whether acute respiratory failure in patients with interstitial lung disease is reversible remains uncertain. Consequently, indications for extracorporeal membrane oxygenation in these patients are still controversial, except as a bridge to lung transplantation. The objective of this study was to clarify in-hospital mortality and prognostic factors in interstitial lung disease patients undergoing extracorporeal membrane oxygenation. METHODS: In this case-control study using the Japanese Diagnosis Procedure Combination database, hospitalized interstitial lung disease patients receiving invasive mechanical ventilation and extracorporeal membrane oxygenation from 2010 to 2017 were reviewed. Patients' characteristics and treatment regimens were compared between survivors and non-survivors to identify prognostic factors. To avoid selection biases, patients treated with extracorporeal membrane oxygenation as a bridge to lung transplantation were excluded. RESULTS: A total of 164 interstitial lung disease patients receiving extracorporeal membrane oxygenation were included. Their in-hospital mortality was 74.4% (122/164). Compared with survivors, non-survivors were older and received high-dose cyclophosphamide, protease inhibitors, and antifungal drugs more frequently, but macrolides and anti-influenza drugs less frequently. On multivariate analysis, the following factors were associated with in-hospital mortality: advanced age (odds ratio [OR] 1.043; 95% confidence interval [CI] 1.009-1.078), non-use of macrolides (OR 0.305; 95% CI 0.134-0.698), and use of antifungal drugs (OR 2.416; 95% CI 1.025-5.696). CONCLUSIONS: Approximately three-quarters of interstitial lung disease patients undergoing extracorporeal membrane oxygenation died in hospital. Moreover, advanced age, non-use of macrolides, and use of antifungal drugs were found to correlate with a poor prognosis.

Re-expansion pulmonary edema following a pneumothorax drainage in a patient with COVID-19.

BACKGROUND: Re-expansion pulmonary edema is an uncommon complication following drainage of a pneumothorax or pleural effusion. While pneumothorax is noted to complicate COVID-19 patients, no case of COVID-19 developing re-expansion pulmonary edema has been reported. CASE REPRESENTATION: A man in his early 40 s without a smoking history and underlying pulmonary diseases suddenly complained of left chest pain with dyspnea 1 day after being diagnosed with COVID-19. Chest X-ray revealed pneumothorax in the left lung field, and a chest tube was inserted into the intrathoracic space without negative pressure 9 h after the onset of chest pain, resulting in the disappearance of respiratory symptoms; however, 2 h thereafter, dyspnea recurred with lower oxygenation status. Chest X-ray revealed improvement of collapse but extensive infiltration in the expanded lung. Therefore, the patient was diagnosed with re-expansion pulmonary edema, and his dyspnea and oxygenation status gradually improved without any intervention, such as steroid administration. Abnormal lung images also gradually improved within several days. CONCLUSIONS: This case highlights the rare presentation of re-expansion pulmonary edema following pneumothorax drainage in a patient with COVID-19, which recovered without requiring treatment for viral pneumonia. Differentiating re-expansion pulmonary edema from viral pneumonia is crucial to prevent unnecessary medication for COVID-19 pneumonia and pneumothorax.

A solitary pulmonary nodule caused by Mycobacterium tuberculosis var. BCG after intravesical BCG treatment: a case report.

BACKGROUND: Intravesical instillation of bacillus Calmette-Guérin (BCG) as a treatment for superficial bladder cancer rarely causes pulmonary complications. While published cases have been pathologically characterized by multiple granulomatous lesions due to disseminated infection, no case presenting as a solitary pulmonary nodule has been reported. CASE PRESENTATION: A man in his 70 s was treated with intravesical BCG for early-stage bladder cancer. After 1 year, he complained of productive cough with a solitary pulmonary nodule at the left lower lobe of his lung being detected upon chest radiography. His sputum culture result came back positive, with conventional polymerase chain reaction (PCR) identifying Mycobacterium tuberculosis complex. However, tuberculosis antigen-specific interferon-gamma release assay came back negative. Considering a history of intravesical BCG treatment, multiplex PCR was conducted, revealing the strain to be Mycobacterium tuberculosis var. BCG. The patient was then treated with isoniazid, ethambutol, levofloxacin, and para-aminosalicylic acid following an antibiotic susceptibility test showing pyrazinamide resistance, after which the size of nodule gradually decreased. CONCLUSION: This case highlights the rare albeit potential radiographic presentation of Mycobacterium tuberculosis var. BCG, showing a solitary pulmonary nodule but not multiple granulomatous lesions, after intravesical BCG treatment. Differentiating Mycobacterium tuberculosis var. BCG from Mycobacterium tuberculosis var. tuberculosis is crucial to determine whether intravesical BCG treatment could be continued for patients with bladder cancer.

A retrospective test for a possible relationship between linezolid-induced thrombocytopenia and hyponatraemia.

WHAT IS KNOWN AND OBJECTIVE: Thrombocytopenia is one of the typical adverse events caused by linezolid (LZD). Recently, some cases of severe hyponatraemia occurring while receiving LZD have been reported. This study investigated a possible relationship between LZD-induced hyponatraemia and thrombocytopenia and identified the risk factors for hyponatraemia and/or thrombocytopenia. METHODS: In this retrospective, single-centre, observational cohort study, 63 hospitalized patients aged over 18 years who received intravenous injection of LZD for more than seven consecutive days in Oita University Hospital between April 2015 and March 2018 were analysed. RESULTS: Thrombocytopenia occurred in 25 (39.7%) patients and hyponatraemia in 11 (17.5%) patients. Seven of 11 patients with hyponatraemia had concurrent thrombocytopenia. Although both serum sodium level and platelet count declined in most patients who developed hyponatraemia, no significant association between thrombocytopenia and hyponatraemia was found. Creatinine clearance level (Ccr) was significantly lower not only in the thrombocytopenia (vs no-thrombocytopenia) but also in the hyponatraemia group (vs no-hyponatraemia group). Univariate and multivariate logistic regression analyses identified different risk factors for thrombocytopenia and/or hyponatraemia (thrombocytopenia: Ccr and administration period; hyponatraemia: serum albumin; thrombocytopenia and hyponatraemia: administration period and serum albumin). WHAT IS NEW AND CONCLUSION: In conclusion, this study found no significant relationship between LZD-induced thrombocytopenia and hyponatraemia and identified some possible risk factors associated with onset of the two adverse events. These require further validation.

Multicenter surveillance of the epidemiology of gram-negative bacteremia in Japan.

This study investigated the epidemiology of adult patients with bacteremia caused by seven major gram-negative bacteria during a year at four university hospitals in Japan. Of the 438 cases included, Escherichia coli (247 patients) was the most frequently isolated pathogen, followed by Klebsiella species (89 patients), Enterobacter species (31 patients), Pseudomonas aeruginosa (29 patients), Bacteroides species (19 patients), Acinetobacter species (12 patients) and Stenotrophomonas maltophilia (11 patients). The overall, crude in-hospital mortality was 16.4%, ranging from 9.7% with Enterobacter species to 54.5% with S. maltophilia. Community- and hospital-acquired bacteremia accounted for 52.5% and 47.5%, respectively. Enterobacteriaceae were isolated from 93.0% of patients with community-acquired bacteremia, whereas non-fermenting bacteria were isolated from 21.6% of patients with hospital-acquired bacteremia. Of the 423 patients analyzed, 86.8% and 13.2% were monomicrobial and polymicrobial infections, respectively, and their in-hospital mortalities were 13.9% and 30.4%, respectively. Although carbapenem-resistant Enterobacteriaceae were not detected, extended-spectrum ß-lactamase (ESBL) production was seen in 24.3% of E. coli and 6.7% of Klebsiella species, respectively. E. coli producing ESBL showed high resistance rates to fluoroquinolones (approximately 90%), in contrast to non-producing-E. coli (approximately 21%). The susceptibilities to carbapenems and fluoroquinolones were approximately 80% for P. aeruginosa, whereas all Acinetobacter species were susceptible to these antibiotics. Bacteroides species showed 100% susceptibility to piperacillin/tazobactam and carbapenems, but only 47.4% were susceptible to clindamycin. Further studies, as well as continued surveillance, are required to determine the appropriate therapeutic strategy for gram-negative bacteremia.