Comparative characteristics of the background and blood test findings in adults with pneumococcal pneumonia and invasive pneumococcal disease: A retrospective study.

INTRODUCTION: Invasive pneumococcal disease (IPD) is often fatal, requiring prompt diagnosis and treatment. To evaluate the factors associated with IPD in adults, we retrospectively investigated its characteristics compared to pneumococcal pneumonia without confirmation of invasion (PP). METHODS: Patients >18 years with PP (n = 79) and IPD (n = 53) from whom Streptococcus pneumoniae was isolated were enrolled from two hospitals between 2011 and 2017. Clinical backgrounds, blood test results at admission, initial antimicrobials administered, isolate serotypes, and outcomes were compared between the PP and IPD groups. RESULTS: Patients with IPD exhibited higher mortality (28.3%) than those with PP (2.5%) (p<0.001), regardless of the type of antimicrobials first administered. The majority (80.0%) of fatal cases of IPD were due to vaccine serotypes. Almost all patients with PP (97.4%) and IPD (88.7%) had underlying disease. C-reactive protein (CRP) ≥17.0 mg/dL (odds ratio [OR], 7.1; 95% CI, 2.7-19.0; p<0.001), white blood cell counts <11.0 × 103/µL (OR, 3.2; 95% CI, 1.3-8.4; p = 0.016), and platelet (PLT) counts <16.2 × 104/µL (OR, 2.8; 95% CI, 1.1-7.4; p = 0.036) were significantly more common in IPD. Moreover, 89.5% of cases with both CRP ≥23.8 mg/dL and PLT <18.5 × 104/µL were diagnosed with IPD. CONCLUSION: Laboratory blood test findings at admission, particularly high CRP and low PLT values, are useful early indicators of IPD in adults. These results could be used to initiate rapid and intensive treatment and improve prognosis.

The Seasonality of Peripheral Venous Catheter-Related Bloodstream Infections.

INTRODUCTION: Although the seasonality of infectious diseases has been widely reported, the seasonality of peripheral venous catheter-related bloodstream infection (PV-CRBSI) has not been investigated. This study investigated the seasonality of PV-CRBSI and its relationship with meteorological conditions. METHODS: A retrospective cohort study of PV-CRBSI at Tokyo Medical University Hospital (Tokyo, Japan), from 2009 to 2019, provided the data for descriptive and time series analyses used to evaluate the number of PV-CRBSI cases per 1000 admissions that occurred each month for each causative organism. By performing univariate and multivariate analyses, the researchers investigated the seasonality of cases and the relationships between meteorological conditions, other external factors, and PV-CRBSIs. RESULTS: This study included a total of 184 PV-CRBSI cases. The mean numbers of PV-CRBSI cases per 1000 admissions caused by all organisms, Bacillus cereus, Gram-positive cocci, and Gram-negative rods were 0.67, 0.15, 0.37, and 0.16 per month, respectively, during the study period. The time series analysis showed that the incidences of PV-CRBSI cases associated with B. cereus and Gram-negative rods were significantly different in the winter/spring from those in the summer/autumn (P < 0.05). The incidence of PV-CRBSI cases caused by B. cereus peaked during summer. The incidence of PV-CRBSI cases caused by B. cereus was significantly positively associated with average monthly temperature, whereas the incidence of PV-CRBSIs caused by Gram-negative rods was significantly negatively associated with average daylight hours. CONCLUSION: The incidence of PV-CRBSIs caused by B. cereus showed seasonality, peaking during the summer, and a significant correlation was found between PV-CRBSIs caused by B. cereus and average monthly temperature.

Use of a toxicity factor to explain differences in nephrotoxicity and myelosuppression among the platinum antitumour derivatives cisplatin, carboplatin and nedaplatin in rats.

The platinum antitumour drugs cisplatin, carboplatin and nedaplatin differ in their toxicity. The relationships between the pharmacokinetics of these drugs and developed parameters for predicting their nephrotoxicity and myelosuppression were investigated. The drugs were administered to male Wistar rats by intravenous bolus or infusion, and linearity of pharmacokinetics, total clearance and the apparent ratio of tissue concentrations of unchanged drug to plasma concentration (Kp app) at steady state were determined. Apparent hydrolysis rates of each drug were determined in-vitro. Nephrotoxicity and myelosuppression were estimated by blood urea nitrogen (BUN) and platelet count, respectively. Tissue exposure to platinum was estimated as the product of the area under the plasma concentration-time curve for unchanged drug (AUC p), Kp app and the apparent hydrolysis rate constant (k hydrolysis), and toxicity factor was defined as the product of Kp app x k hydrolysis as an intrinsic drug parameter. The relationship between AUC p x toxicity factor and BUN fitted well to an Emax model. In bone marrow, this function was also correlated with platelet count. In summary, the product of AUC p x toxicity factor is a factor determining the pharmacokinetics of platinum drug-induced nephrotoxicity and myelosuppression in rats, and this toxicity factor may be a useful parameter for predicting the degree of toxicity of platinum antitumour compounds.