The impact of direct inoculation of ascites into blood culture bottles on ascites culture positivity.

Objective: Assess whether direct inoculation of ascites into blood culture bottles would improve ascites culture yield. Design: Pre-post-study. Setting: The study was performed at a quaternary academic medical center in Houston, Texas, including all inpatient and emergency department encounters. Patients: Ascites cultures collected from November 2020 to December 2022 were reviewed and screened for spontaneous bacterial peritonitis. Patients were excluded if a prior ascites culture from the same patient was already included in the study or if there was evidence of secondary bacterial peritonitis. Intervention: In the pre-intervention period, ascites cultures were collected into a sterile container and inoculated onto/into solid and liquid media. In the post-intervention period, ascites cultures were instead directly inoculated into bioMérieux© blood culture bottles at the bedside. Results: 114 patients met inclusion and exclusion criteria, 61 pre-intervention and 53 post-intervention. Overall ascites culture positivity was 15.8% (18/114), 11.5% (7/61) pre-intervention vs 20.8% (11/53) post-intervention. After adjusting for confounders, the intervention had a trend toward a significant effect on ascites culture positivity (P = 0.077). No significant differences were seen in time to positivity, hospital length of stay, or 30-day readmission. Conclusions: Direct inoculation of ascitic fluid into blood culture bottles led to a small increase in culture yield but lacked statistical significance. This lack of significance may be due to the study being underpowered. Further studies are required to investigate if this is due to procedural inefficiencies (eg, inadequate inoculation volumes) or pragmatic clinical practice considerations (ie, high rates of pre-culture antibiotics).

Acute and Chronic Infectious Prostatitis in Older Adults.

Acute and chronic bacterial prostatitis are clinically significant entities that can be difficult to diagnose and appropriately treat. Herein, we review when to suspect these clinical conditions, how to diagnose them, and how to effectively treat them based on the extant literature. Our aim was to equip the practicing clinician with the ability to proficiently diagnose and manage acute and chronic bacterial prostatitis, particularly in older patients.

IRF6 Regulates Alternative Activation by Suppressing PPARγ in Male Murine Macrophages.

Aberrant proinflammatory and suppressed anti-inflammatory (alternative; M2) macrophage activation underlies the chronic inflammation associated with obesity and other metabolic disorders. This study demonstrates a critical role for interferon regulatory factor 6 (IRF6) in regulating macrophage M2 activation by suppressing peroxisome proliferator-activated receptor-γ (PPARγ) expression, a critical regulator of alternative macrophage polarization. The data demonstrate suppression of IRF6 in both M2 macrophages and obese adipose tissue macrophages. Using gain- and loss-of-function strategies, we confirmed that IRF6 knockdown enhanced M2 activation, whereas IRF6 overexpression dramatically attenuated M2 activation. Computational target prediction analysis coupled with chromatin immunoprecipitation indicated that IRF6 suppresses PPARγ through binding IRF recognition sites located upstream of the PPARγ coding region. Taken together, our results suggest that an IRF6/PPARγ regulatory axis suppresses anti-inflammatory responses in bone marrow-derived macrophages and provides references for future study addressing dysregulated metabolic and immunologic homeostasis of obese adipose tissue.

miR-150 regulates obesity-associated insulin resistance by controlling B cell functions.

Adipose tissue resident B cells account for more than 20% of stromal cells within visceral adipose tissues; however, their functions in the adipose tissue niche are poorly elucidated. Here we report that miR-150 modulates adipose tissue function by controlling activation of B cells and their interactions with other immune cells. miR-150KO mice displayed exacerbated obesity-associated tissue inflammation and systemic insulin resistance, which is recapitulated by adoptive transfer of B cells, but not purified immunoglobulin, into obese B(null) mice. Using purified cell populations, we found that enhanced proinflammatory activation of adipose tissue T cells and macrophages was due to miR-150KO B cells action but not cell-autologous mechanisms. miR-150KO B cells displayed significantly enhanced antigen presentation upon stimulation, ultimately leading to elevated inflammation and insulin resistance, compared to wild type B cells. Knockdown of identified miR-150 target genes, Elk1, Etf1 or Myb attenuated B cell action by altering B cell receptor pathways and MHCII cell surface presentation. Our results demonstrate a critical role for miR-150 in regulating B cell functions in adipose tissue which ultimately regulate both metabolic and immunologic homeostasis in the adipose tissue niche.

MicroRNA-223 is a crucial mediator of PPARγ-regulated alternative macrophage activation.

Polarized activation of adipose tissue macrophages (ATMs) is crucial for maintaining adipose tissue function and mediating obesity-associated cardiovascular risk and metabolic abnormalities; however, the regulatory network of this key process is not well defined. Here, we identified a PPARγ/microRNA-223 (miR-223) regulatory axis that controls macrophage polarization by targeting distinct downstream genes to shift the cellular response to various stimuli. In BM-derived macrophages, PPARγ directly enhanced miR-223 expression upon exposure to Th2 stimuli. ChIP analysis, followed by enhancer reporter assays, revealed that this effect was mediated by PPARγ binding 3 PPARγ regulatory elements (PPREs) upstream of the pre-miR-223 coding region. Moreover, deletion of miR-223 impaired PPARγ-dependent macrophage alternative activation in cells cultured ex vivo and in mice fed a high-fat diet. We identified Rasa1 and Nfat5 as genuine miR-223 targets that are critical for PPARγ-dependent macrophage alternative activation, whereas the proinflammatory regulator Pknox1, which we reported previously, mediated miR-223-regulated macrophage classical activation. In summary, this study provides evidence to support the crucial role of a PPARγ/miR-223 regulatory axis in controlling macrophage polarization via distinct downstream target genes.