Differential distribution of cholesterol pools across arteries under high-cholesterol diet.

Excessive cholesterol constitutes a major risk factor for vascular disease. Within cells, cholesterol is distributed in detergent-sensitive and detergent-resistant fractions, with the largest amount of cholesterol residing in cellular membranes. We set out to determine whether various arteries differ in their ability to accumulate esterified and non-esterified cholesterol in detergent-sensitive versus detergent-resistant fractions throughout the course of a high-cholesterol diet. Male Sprague-Dawley rats were placed on 2 % cholesterol diet while a control group was receiving iso-caloric standard chow. Liver, aorta, and pulmonary, mesenteric, and cerebral arteries were collected at 2-6, 8-12, 14-18, and 20-24 weeks from the start of high-cholesterol diet. After fraction separation, esterified and free non-esterified cholesterol levels were measured. In all arteries, largest cholesterol amounts were present in detergent-sensitive fractions in the non-esterified form. Overall, cholesterol in aorta and cerebral arteries was elevated during 14-18 weeks of high-cholesterol diet. Cerebral arteries also exhibited increase in esterified cholesterol within detergent-sensitive domains, as well as increase in cholesterol level in the detergent-resistant fraction at earlier time-points of diet. Pulmonary artery and mesenteric artery were largely resistant to cholesterol accumulation. Quantitative polymerase chain reaction (qPCR) analysis revealed up-regulation of low-density lipoprotein receptor (Ldlr) and low-density lipoprotein receptor-related protein 1 (Lrp1) gene expression in cerebral arteries when compared to mesenteric and pulmonary arteries, respectively. In summary, we unveiled the differential ability of arteries to accumulate cholesterol over the course of a high-cholesterol diet. The differential accumulation of cholesterol seems to correlate with the up-regulated gene expression of proteins responsible for cholesterol uptake.

Short-duration treatment for catheter-associated urinary tract infections in critically ill trauma patients.

BACKGROUND: The optimal treatment duration for catheter-associated urinary tract infection (CA-UTI) in critically ill patients is unclear. The Infectious Diseases Society of America recommends up to 14 days of therapy; however, short-duration therapy (SDT) for 3 days to 5 days is often used in trauma intensive care unit (ICU) patients at our center. The efficacy of SDT for CA-UTI has not been studied in this population. The objective was to evaluate the efficacy of SDT for CA-UTI in trauma ICU patients. METHODS: This retrospective study of patients with CA-UTI in a trauma ICU included patients with a urine culture growing bacteria of 100,000 CFU/mL or greater and definitive antibiotic treatment. Urine cultures were collected as part of standard workups for suspected sepsis. Duration of therapy was at the discretion of the trauma team. Exclusion criteria included concomitant infection, renal replacement therapy, or pregnancy. Clinical success and microbiologic success were evaluated. RESULTS: One hundred ninety-two patients were evaluated, and 77 patients with SDT were included. Mean (SD) age was 49 (22) years, median Injury Severity Score (ISS) was 27 (interquartile range, 18-34), and median ICU stay was 17 days (interquartile range, 1-33 days). Mean (SD) duration of CA-UTI therapy was 4 (1) days (range, 3-5 days) with most patients (42%) receiving 5 days. The most common organisms were Escherichia coli, Enterococcus species, and Pseudomonas species. The clinical success rate was 82% (63 of 77), and the microbiologic success rate was 75% (36 of 48). Overall mortality was 4%, but no deaths were CA-UTI related. CONCLUSION: SDT provided an acceptable clinical success rate in critically ill trauma patients, which was similar to studies of CA-UTI in other populations. These results suggest that SDT could be considered an option for treating CA-UTIs in trauma ICU patients. LEVEL OF EVIDENCE: Therapeutic study, level V.

Treatment of Rhizobium radiobacter bacteremia in a critically ill trauma patient.

OBJECTIVE: To report the first case of Rhizobium radiobacter bacteremia in a critically ill trauma patient. CASE SUMMARY: A 36-year-old female trauma patient hospitalized at The Regional Medical Center at Memphis developed bacteremia due to Rhizobium radiobacter on hospital day 9. The central line catheter tip culture from the same hospital day was negative. No source for the R radiobacter bacteremia was identified. Empirical and definitive antibiotic therapy consisted of cefepime 2 g intravenously every 8 hours for at total of 8 days. On completion of antibiotics, the patient demonstrated clinical resolution by immediate defervescence and gradual normalization of her white blood cell count. She demonstrated microbiologic success of therapy with negative blood cultures on hospital days 22, 34, 45, and 61. She was discharged on hospital day 80. DISCUSSION: Rhizobium species are common soil and plant pathogens that rarely cause infections in humans. Previous reports of Rhizobium infections have been in immunocompromised patients; generally those with cancer or HIV infection. Intravenous catheters have commonly been cited as the source of infection. The trauma patient in this case constitutes a unique presentation of R radiobacter bacteremia when compared with other case reports. Her indwelling catheter was not the source of her infection, and her only identifiable risk factor for R radiobacter infection was hospitalization. However, she did possess potential reasons for development of an infection with an unusual organism such as R radiobacter. Potential immune modulating therapies included blood transfusions, opioid analgesics, benzodiazepines, general anesthetics, and surgical procedures. Finally, trauma itself has been associated with some degree of immunosuppression. All these issues may have placed the patient in this case at risk of an opportunistic infection like R radiobacter. CONCLUSION: Based on this case, R radiobacter may be considered a potential pathogen causing bacteremia in critically ill trauma patients.

Treatment of Chryseobacterium indologenes ventilator-associated pneumonia in a critically ill trauma patient.

OBJECTIVE: To report a case of Chryseobacterium indologenes ventilator-associated pneumonia (VAP) in a critically ill trauma patient. CASE SUMMARY: This report describes a 66-year-old critically ill trauma patient who developed VAP, which was caused by C indologenes. The patient was injured in a riding lawn mower accident that trapped him underwater in a pond. The patient required surgery for intra-abdominal injuries and was mechanically ventilated in the trauma intensive care unit. On hospital day 5, the patient developed signs and symptoms of VAP. A diagnosis of C indologenes VAP was confirmed based on a quantitative culture from a bronchoscopic bronchoalveolar lavage. The patient's infection was successfully treated with moxifloxacin for 2 days followed by cefepime for 7 days. DISCUSSION: Formally known as Flavobacterium indologenes, C indologenes is a Gram-negative bacillus normally found in plants, soil, foodstuffs, and fresh and marine water sources. Recently, worldwide reports of C indologenes infections in humans have been increasing, though reports from the United States are still rare. Bacteremia and pneumonia are the most commonly reported infections, and most patients are immunocompromised. The current case differs from most previous reports because this patient was in the United States and did not have any traditional immunocompromised states (eg, transplant, cancer, HIV/AIDS, or corticosteroid use). CONCLUSION: This case report demonstrates that C indologenes can cause VAP in a trauma ICU patient.