Aeromonas hydrophila Community-Acquired Bacterial Pneumonia With Septic Shock in a Chronic Lymphocytic Leukemia Patient Due to Absolute Neutropenia and Lymphopenia.

Aeromonas hydrophila is a gram-negative (GN) bacillus with an opportunistic potential in immunocompromised patients. They are ubiquitary in fresh and brackish water capable of infecting healthy and immunosuppressed patients. Clinical manifestations vary in healthy hosts compared to immunocompromised patients. Community-acquired bacterial pneumonia (CABP) is an infrequent clinical presentation of A. hydrophila infection, even in immunosuppressed patients. It is also an uncommon cause of nosocomial and drowning-related pneumonia. Although a rare cause of CABP, the clinical course is fulminant with higher mortality due to lower clinical suspicion. Here, we present an immunocompromised 63-year-old Caucasian male with chronic lymphocytic leukemia (CLL) presenting with acute A. hydrophila CABP with septic shock due to absolute neutropenia and lymphopenia.

Bone marrow adipose tissue does not express UCP1 during development or adrenergic-induced remodeling.

Adipocytes within the skeleton are collectively termed bone marrow adipose tissue (BMAT). BMAT contributes to peripheral and local metabolism, however, its capacity for cell-autonomous expression of uncoupling protein 1 (UCP1), a biomarker of beige and brown adipogenesis, remains unclear. To overcome this, Ucp1-Cre was used to drive diphtheria toxin expression in cells expressing UCP1 (Ucp1Cre+/DTA+). Despite loss of brown adipose tissue, BMAT volume was not reduced in Ucp1Cre+/DTA+ mice. Comparably, in mTmG reporter mice (Ucp1Cre+/mTmG+), Ucp1-Cre expression was absent from BMAT in young (3-weeks) and mature (16-weeks) male and female mice. Further, ß3-agonist stimulation failed to induce Ucp1-Cre expression in BMAT. This demonstrates that BMAT adipocytes are not UCP1-expressing beige/brown adipocytes. Thus, to identify novel and emerging roles for BMAT adipocytes in skeletal and whole-body homeostasis, we performed gene enrichment analysis of microarray data from adipose tissues of adult rabbits. Pathway analysis revealed genetic evidence for differences in BMAT including insulin resistance, decreased fatty acid metabolism, and enhanced contributions to local processes including bone mineral density through candidate genes such as osteopontin. In sum, this supports a paradigm by which BMAT adipocytes are a unique subpopulation that is specialized to support cells within the skeletal and hematopoietic niche.