Streptococcus pneumoniae is an opportunistic Gram-positive pathogen that can cause invasive disease. Recent studies have shown that S. pneumoniae is able to invade the myocardium and kill cardiomyocytes, with one-in-five adults hospitalized for pneumococcal pneumonia having a pneumonia-associated adverse cardiac event. Furthermore, clinical reports have shown up to a 10-year increased risk of adverse cardiac events in patients formerly hospitalized for pneumococcal bacteremia. In this study, we investigated the ability of nine S. pneumoniae clinical isolates, representing eight unique serotypes, to cause cardiac damage in a mouse model of invasive disease. Following intraperitoneal challenge of C57BL/6 mice, four of these strains (D39, WU2, TIGR4, and 6A-10) caused high-grade bacteremia, while CDC7F:2617–97 and AMQ16 caused mid- and low-grade bacteremia, respectively. Three strains did not cause any discernible disease. Of note, only the strains capable of high-grade bacteremia caused cardiac damage, as inferred by serum levels of cardiac troponin-I. This link between bacteremia and heart damage was further corroborated by Hematoxylin & Eosin and Trichrome staining which showed cardiac cytotoxicity only in D39, WU2, TIGR4, and 6A-10 infected mice. Finally, hearts infected with these strains showed varying histopathological characteristics, such as differential lesion formation and myocytolysis, suggesting that the mechanism of heart damage varied between strains.

Background There are two conventional modalities used to perform therapeutic plasma exchange (TPE): centrifuge TPE (cTPE) or membrane TPE (mTPE). There is limited data on complications with mTPE. Objective We sought to better understand the patient and machine complications of mTPE compared to cTPE. We hypothesize that our protocol for mTPE using heparin anticoagulation is well‐tolerated. Methods In this retrospective cohort study of children <21 years of age, we evaluated differences in patient and machine characteristics and complications between cTPE (with citrate anticoagulation) vs mTPE (with heparin anticoagulation). Results Of the 105 patients who met inclusion/exclusion criteria, 63 received cTPE and 42 mTPE via Prismaflex. Those who used mTPE were younger (4.8 ± 2.8 years vs 15.2 ± 3.7 years, P = .0001) and weighed less (19.5 ± 10.6 vs 71.7 ± 28.5 kg, P = .0001). There were no significant differences in patient‐related complications or indications for TPE between the two modalities. Of the 1031 therapies performed,1003 therapies were analyzed (646 using cTPE and 357 using mTPE) due to exclusion criteria. No significant difference in patient complications were detected between groups. Machine‐related complications were infrequent in both approaches. More circuits clotted during mTPE than during cTPE (6.7% [24/357] vs 0% [0/646]; P < 0.001). Conclusion Although we use mTPE in smaller children, we showed low rates of complications that were not statistically different from cTPE performed in older children. While the overall rate of circuit clotting using mTPE was low, it occurred more commonly than with cTPE.