Evidence for intracellular Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a significant cause of global morbidity and mortality. Although it is often regarded as an extracellular pathogen toward human cells, numerous investigations report its ability to survive and replicate within host cells, and additional studies demonstrate specific mechanisms enabling it to adopt an intracellular lifestyle. This ability of P. aeruginosa remains less well-investigated than that of other intracellular bacteria, although it is currently gaining attention. If intracellular bacteria are not killed after entering host cells, they may instead receive protection from immune recognition and experience reduced exposure to antibiotic therapy, among additional potential advantages shared with other facultative intracellular pathogens. For this review, we compiled studies that observe intracellular P. aeruginosa across strains, cell types, and experimental systems in vitro, as well as contextualize these findings with the few studies that report similar observations in vivo. We also seek to address key findings that drove the perception that P. aeruginosa remains extracellular in order to reconcile what is currently understood about intracellular pathogenesis and highlight open questions regarding its contribution to disease.

Initial Experience with Exoscopic-Based Intraoperative Indocyanine Green Fluorescence Video Angiography in Cerebrovascular Surgery: A Preliminary Case Series Showing Feasibility, Safety, and Next-Generation Handheld Form-Factor.

BACKGROUND: Native vessel patency and residual lesion are primary sources of morbidity in cerebrovascular surgery (CVS) that require real-time visualization to inform surgical judgment, as is available in endovascular procedures. Micro Doppler and microscopy-based indocyanine green (ICG) fluorescence are promising evolutions compared with intraoperative angiography (IA), and digital subtraction angiography (DSA) remains the gold standard. Exoscopic visualization in CVS is emerging; however, the feasibility of exoscopic-based ICG (ICG-E) for CVS has not yet been reported. To objective of the study was to provide initial experience with ICG-E video angiography in CVS. METHODS: Retrospective study in which 2 ICG-E form-factors (exoscopic-coupled or self-contained handheld imager) were used to determine native vessel patency and residual and compared with DSA. RESULTS: Eleven patients (8 aneurysms, 3 arteriovenous malformations [AVMs]) were included. ICG-E was feasible in all, providing real-time information leading to operative decisions affecting surgical judgment. For aneurysms, discordance of IA with ICG-E and DSA was 12%. In 1 patient, IA showed non-flow-restrictive branch stenosis; however, both ICG and DSA showed patency. All AVMs were fully obliterated, with 100% concordance among all modalities. ICG averaged 4.2 mg dose/run (1-4 doses/case); 1.25 mg was the lowest dose allowing visualization with no advantage with escalating dosages. There were no intraoperative/perioperative complications. CONCLUSIONS: In this preliminary study, ICG-E was safe and feasible, providing real-time visualization informing surgical decision making. The last 4 cases (2 aneurysms and 2 AVMs) evolved toward a portable handheld device, a readily accessible real-time modality providing contextual anatomic and flow visualization. Larger studies are needed to assess broader safety, dose escalation, and efficacy.