Journal of Infection and Chemotherapy最新文献

Legionella pneumonia is an important cause of community-acquired pneumonia (CAP). The Japanese Respiratory Society (JRS) pneumonia guideline 2024 proposed use of the Legionella Diagnostic Prediction Score for the management of CAP in adults. The committee for the JRS pneumonia guideline is required to verify the validity of the Legionella Diagnostic Prediction Score for the next revision. In addition, it is necessary to determine appropriate cutoff scores by examining all pneumonia cases. In the present study, we validated the usefulness of the Legionella Diagnostic Prediction Score using SARS-CoV-2 Omicron CAP. We analyzed 116 patients with L. pneumophila CAP and 947 patients with SARS-CoV-2 Omicron CAP. Among Omicron cases, the median Legionella Diagnostic Prediction Score was identical among BA.1, BA.2, BA.5, XBB lineage, BA.2.86 and JN.1 subvariants. The median Legionella Diagnostic Prediction Score was significantly higher in the L. pneumophila CAP group than the SARS-CoV-2 Omicron CAP group (4 vs 1, p<0.0001). When targeting all 947 patients with Omicron subvariants, the diagnostic sensitivity and specificity for the presumptive diagnosis of L. pneumophila CAP were 90.5% and 90.8%, respectively, when a total score ≥ 3 points was set as the cutoff level. When the cutoff score was ≥ 4 points, the diagnostic sensitivity and specificity for presumptive diagnosis of L. pneumophila CAP were 76.7% and 99.6%, respectively. Our results demonstrated that the Legionella Diagnostic Prediction Score had good diagnostic ability during the SARS-CoV-2 Omicron variant epidemic period. To set optimal indicators and cutoff values for the Legionella Diagnostic Prediction Score, the policy of the committee for the JRS pneumonia guideline is to continue testing for all pneumonia types.

Introduction: The bacterium Corynebacterium urealyticum produces urease and can cause encrusted pyelitis, a condition characterized by calcifications of the renal pelvis and ureteral wall, which may obstruct the urinary tract. We describe a case of encrusted pyelitis caused by C. urealyticum in a kidney transplant patient presenting with altered consciousness due to hyperammonemia.

Case presentation: An 81-year-old woman with a history of cadaveric kidney transplantation, thirty years prior, presented with acute altered consciousness during hospitalization. Laboratory findings showed acute renal failure and hyperammonemia, and urinalysis revealed high pH (>9.0) and pyuria. Abdominal non-contrast computed tomography revealed calcification of the renal pelvis and hydronephrosis. C. urealyticum was isolated from both blood and urine cultures. A diagnosis of encrusted pyelitis and hyperammonemia caused by C. urealyticum was made, and intravenous vancomycin was administered. Following the initiation of vancomycin and the temporary hemodialysis, her hyperammonemia and altered consciousness rapidly improved. Treatment with vancomycin resulted in a reduction of the urinary tract encrustation.

Conclusion: This case highlights C. urealyticum as a urinary pathogen that can lead to encrusted pyelitis, hyperammonemia, and altered consciousness in renal transplant patients.

Introduction: Teicoplanin (TEIC) is typically administered as a loading dose over 36-48 h. Achieving an effective concentration quickly is expected to treat severe infections, such as sepsis and methicillin-resistant Staphylococcus aureus infections. We aimed to identify the TEIC loading dose to be completed within 24 h, targeting the concentration of 15-30 μg/mL and factors affecting the loading dose by utilizing the decision tree (DT) model.

Methods: Patients treated with TEIC between January 2017 and December 2022 who met the 24-h loading dose regimen were enrolled. A LD_22.5 (corrected TEIC loading dose targeting concentration of 22.5 μg/mL) was determined, factors affecting the concentration were extracted, and a DT model was constructed. The validity of the DT was assessed using the coefficient of determination (R²) in the DT and population pharmacokinetics (PopPK) models for LD_22.5.

Result: A total of 149 patients were divided into training (n = 104, 70 %) and test groups (n = 45, 30 %). We indicated an average of 14.5 mg/kg for LD_22.5 and extracted four factors (estimated glomerular filtration rate, age, albumin, and C-reactive protein) from the DT model. The R² values were 0.724, 0.695, 0.681, and 0.653 for the DT models (training and test groups) and two PopPK models, respectively.

Conclusion: We established a 24-h loading dose regimen targeting the TEIC concentration of 15-30 μg/mL and identified four factors affecting the loading dose by using DT. By following the indicated DT algorithm flowchat, optimal decisions regarding the loading dose could be made for TEIC therapy.

Background: Prolonged installation of a nephrostomy tube causes colonization of various microorganisms within the lumen of the tube, leading to the development of nephrostomy tube-associated pyelonephritis (NTAP). Patients with malignancy, often necessitating long-term installation of a nephrostomy tube, are susceptible to NTAP. However, information regarding the characteristics of NTAP in this population is limited.

Methods: We reviewed 43 NTAP cases of patients with malignancy in a cancer center and examined causative and non-causative microorganisms among those detected in urine culture. Causative microorganisms were defined as (1) those detected simultaneously in urine and blood cultures or (2) those detected in monomicrobial urine culture and to which physicians administered active antimicrobials for ≥5 days. Non-causative microorganisms were defined as those to which active antimicrobials were given for a total of <5 days.

Results: Patients in 42 of the 43 NTAP cases recovered with antimicrobial therapy for ≥7 days. Causative microorganisms were identified in 25 cases, where Escherichia coli and Klebsiella pneumoniae were most frequent. All enterococci other than Enterococcus faecalis, Corynebacterium species, and Candida species other than Candida albicans and most of Stenotrophomonas maltophilia detected in urine culture were considered non-causative of NTAP.

Conclusion: E. coli was a common organism causing NTAP of this population. Several microorganisms resistant to cephalosporin were non-causative of NTAP, for which administration of antimicrobials may be unnecessary even if detected in urine culture.

Background: Multiple myeloma (MM) is a common hematologic malignancy and immune dysfunction is a hallmark of the disease. It leads to an increased infection risk, which is still a major cause of mortality. The infection spectrum and characteristics have evolved with the introduction of novel agents. An understanding of risk factors that increasing susceptibility to infection is critical in fighting them. This retrospective study aimed to identify risk factors associated with infection and develop nomogram to qualify the risk of infection.

Methods: We retrospectively reviewed the data of patients who were diagnosed with MM between April 1, 2018 and December 31, 2021 in our department. Independent predictors for infection were determined by the univariate and multivariate logistic regression analysis. Nomogram was established and evaluated by receiver operating characteristic (ROC) curve, calibration curve and decision curve analysis (DCA).

Results: A total of 230 MM patients who were diagnosed or treated in our department were included. Infections were identified in 37.4% of MM patients in the first treatment course. The most common infection was the pulmonary infection. The first treatment course had the highest infection rate. With three or more comorbidities, anemia, high LDH level and high β2-MG level were independent risk factors for infection in MM patients during the induction period. The area under the curve (AUC) of nomogram was 0.746 (95% CI: 0.679-0.814). The calibration curve and DCA indicated the good performance of the nomogram.

Conclusion: Multiple myeloma patients with one or more of these mentioned risk factors should be monitored with particular care in order to decrease the incidence and severity of infective complications. Nomogram was established to predict the incidence of infection in MM patients. Nomogram has satisfactory accuracy, and clinical utility may benefit for clinical decision-making.

Background: Invasive group A Streptococcus (iGAS) infections are rare but potentially fatal. Although the number of invasive group A Streptococcus (iGAS) infections decreased during the coronavirus disease (COVID-19) pandemic, it sharply increased worldwide following the pandemic due to the emergence of M1_UK strains. In Japan, non-fluminant iGAS infections have not been included in the national survey notification system. Therefore, the clinical and microbiological characteristics of iGAS infection are unknown. In this study, we aimed to clarify the clinical and microbiological characteristics of pediatric iGAS infections.

Methods: We conducted a case-series analysis of children aged 0-15 years with positive Streptococcus pyogenes cultures from otherwise sterile sites, diagnosed between July 2018 and June 2024. Clinical data were extracted from the electronic medical records. Samples of clinical isolates were sent to the Public Health Research Institute for further analysis.

Results: We identified 11 patients (median age, 5 years [interquartile range 1-8.5 years]; 6 girls). The incidence rate of the iGAS infections was highest in 2024, with 3 cases in 6 months. Primary bacteremia without focal infection was the predominant diagnosis, followed by skin and soft tissue infections with bacteremia. Among the 11 iGAS infections, 9 isolates were available for additional microbiological tests. M12 and M1 strains were predominant (four cases each). Three of the four M1 isolates were M1_UK strains.

Conclusions: In the present study, the increasing incidence of iGAS infection and clinical diagnoses are similar to those reported in other countries; however, M12 strains as well as M1 strains are predominant.

Introduction: Ruminococcus gnavus is a microbiota-forming, gram-positive coccus reportedly associated with several diseases, such as Crohn's disease. The number of in vitro studies on it is increasing. However, its clinical information is lacking in the literature, with only a few case reports published to date. To elucidate the significance of this organism, we describe its clinical characteristics in this study.

Methods: During the study period (2013-2022), we identified 11 patients with R. gnavus bacteremia and conducted a retrospective chart review. Cases identified to be contaminated were excluded. We found 11 reports of R. gnavus bacteremia on PubMed and reviewed their clinical characteristics.

Results: Eleven R. gnavus bloodstream infection cases were identified in our facility. The median age of the patients was 83 years (interquartile range: 73.75-87.25). Seven cases had at least one documented intestinal lesion including three with malignancy cases, and two cases had uncompensated cirrhosis. In most cases, bacterial translocation was suspected as the entry mechanism. Among the 11 R. gnavus bloodstream infections, 7 (63.6 %) were associated with intestinal lesions, and 2 (18.2 %) had a history of suspected bacterial translocation without documented intestinal lesions.

Conclusion: To the best of our knowledge, this is the largest cohort study on R. gnavus bloodstream infections. Intestinal entry was suspected in more than 80 % of cases in both our cohort and the literature review cohort. For cases of bacteremia with an unknown etiology due to R. gnavus, a thorough examination of gastrointestinal lesions should be performed.

Objectives: There are limited information that need to do appropriate treatment including duration of antibiotic treatments, timing of urinary drainage and pathogenesis of bacteria in calculous pyelonephritis. In the present study, we investigated real-world data on clinical features and succeeded treatment strategies in calculous pyelonephritis cases in our hospital, then, aimed to make predictive model estimating duration of intravenous antibiotics treatment.

Methods: Participants were 163 consecutive patients diagnosed with calculous pyelonephritis who underwent antibiotics treatments between 2017 and 2023 in our in-patients' clinic. Candidates for explanatory variables that may affect duration of antibiotic treatments were age, gender, body mass index, stone location, stone size, septic status, blood culture, urine drainage, indwelling urethral catheter, diabetes mellitus and steroid intake.

Results: Duration of intravenous antibiotics treatment was 6 days in median (IQR: 4-8 days). Indwelling DJ stent or percutaneous nephrostomy were undergone in 74 (45.4 %) patients. Multiple regression analysis revealed that gender, age, indwelling urethral catheter, septic status and management of urine drainage independently affected essential duration of intravenous antibiotics treatment and regression coefficient estimates of those factors respectively were 0.998, 0.890, 2.487, 1.462, 1.293 with constant of 2.464.

Conclusions: Our preliminary multiple regression models for predicting duration of intravenous antibiotics treatment may be useful to judge the timing of changing treatment strategies for patients who would not improve at around estimated intravenous antibiotics treatment periods. If vital signs were stable, it may be acceptable to judge urine drainage from above the urinary stone at around two days after intravenous antibiotic treatments.

Introduction: Staphylococcus aureus bacteremia (SAB), especially when caused by methicillin-resistant S. aureus (MRSA), is of considerable clinical importance. In recent years, the proportion of MRSA among S. aureus has decreased, and a relative increase in the proportion of methicillin-susceptible S. aureus (MSSA) has been observed. It is therefore necessary to consider both MRSA and MSSA when assessing the microbiological and clinical significance of SAB.

Materials and methods: We included SAB cases from the Nara Medical University Hospital between January 2015 and February 2017. We performed drug susceptibility testing, toxicity gene analysis, multilocus sequence typing (MLST), and polymerase chain reaction-based open reading frame typing (POT) of stored strains to integrate clinical and bacteriological characteristics.

Results: There were 90 cases during the experimental period (42 MRSA and 48 MSSA), with 30-day mortality rates of 19 % for MRSA and 10.4 % for MSSA. Deaths were more frequently complicated by septic shock and disseminated intravascular coagulation. MLST studies showed that ST8, ST764, ST1, and ST15 were prevalent in the MRSA group, whereas ST5, ST188, and ST12 were prevalent in MSSA. Infective endocarditis cases had a long time from onset to the initiation of effective antimicrobials and were all MSSA. MLST and POT results correlated well, and POT appeared to have better discriminatory power.

Conclusions: The severity and mortality of SAB, along with the microbiological characteristics of causative isolates, vary by location and time. Continued studies integrating clinical and microbiological investigations are thus needed.