76. Validation of Systemic Inflammatory Mediators as Biomarkers for Severity and Adverse Outcomes in Clostridium difficile Infection

Background

Clostridium difficile infection (CDI) can result in severe disease and death. We are currently unable to identify patients at risk for developing adverse outcomes. We previously showed multiple inflammatory mediators were associated with severity and adverse outcomes. Here, we set out to validate these findings in patients and a murine model of CDI.

Methods

CDI was diagnosed by the clinical microbiology laboratory. Sera were collected ≤48 hours after diagnosis from pilot (October 2010–November 2012) and validation (January–September 2016) cohorts. Inflammatory mediators were measured with a custom multiplex assay. IDSA severity was defined as serum creatinine >1.5-fold above baseline or white blood cell count >15,000 cells/mL. The 30-day outcomes were all-cause mortality and disease-related complications (DRCs): ICU admission, colectomy, or death attributed to CDI. We sought to validate our patient findings in a murine model of CDI: 67 antibiotic-treated mice were infected with 630 g (37 mice), a low virulence strain, or VPI 10463 (30 mice), a highly virulent strain. Host responses were assessed with a murine version of the multiplex panel. Unadjusted and adjusted models were built using logistic and L1 regression, respectively.

Results

The pilot cohort had 156 CDI cases; 63 (40%) with IDSA severity. The inflammatory response in IDSA severe cases was distinct based on redundancy analysis of all measured analytes (P = 0.01). In unadjusted analysis, IL-2R, IL-6, and procalcitonin associated with severity (P < 0.001, P = 0.003, and P = 0.003, respectively). The same findings were seen in the validation cohort of 272 cases (Figure 1). Unadjusted analyses revealed several predictors of severity and outcomes (Table 1). Adjusted models performed well (Figure 2) with AUCs of 0.74 [0.67–0.81] (IDSA severity), 0.89 [0.83–0.95] (death), and 0.84 [0.74–0.95] (DRCs). Application of each model to the mouse cohort for high vs. low virulence infections revealed AUCs of 0.59 [0.44–0.74], 0.96 [0.90–1.0], and 0.89 [0.81–0.97] (Figure 3).

Conclusion

In both humans and a murine CDI model, a panel of biomarkers from sera associated with severe CDI and predicted adverse outcomes. Our results support the possibility of a serum-based biomarker panel to inform medical decision-making for patients with CDI.

Disclosures

All Authors: No reported Disclosures.

Metabolism of the Flavonoid Epicatechin by Laccase of Colletotrichum gloeosporioides and Its Effect on Pathogenicity on Avocado Fruits

ABSTRACT During avocado fruit ripening, decreasing levels of the flavonoid epicatechin have been reported to modulate the metabolism of preformed antifungal compounds and the activation of quiescent Colletotrichum gloeosporioides infections. Epicatechin levels decreased as well when C. gloeosporioides was grown in the presence of epicatechin in culture. Extracts of laccase enzyme obtained from decayed tissue and culture media fully metabolized the epicatechin substrate within 4 and 20 h, respectively. Purified laccase protein from C. gloeosporioides showed an apparent MW of 60,000, an isoelectric point at pH 3.9, and maximal epicatechin degradation at pH 5.6. Inhibitors of fungal laccase such as EDTA and thioglycolic acid reduced C. gloeosporioides symptom development when applied to ripening susceptible fruits. Isolates of C. gloeosporioides with reduced laccase activity and no capability to metabolize epicatechin showed reduced pathogenicity on ripening fruits. On the contrary, Mexican isolates with increasing capabilities to metabolize epicatechin showed early symptoms of disease in unripe fruits. Transcript levels of cglac1, encoding C. gloeosporioides laccase, were enhanced during fungal development in the presence of epicatechin at pH 6.0, where avocado fruits are susceptible to fungal attack. But transcript increase was not detected at pH 5.0, where the fruit is resistant to fungal attack. The present results suggest that biotransformation of epicatechin by C. gloeosporioides in ripening fruits is followed by the decline of the preformed antifungal diene compound, resulting in the activation of quiescent infections.

Professionals' perceptions of psychotropic medication in residential facilities for individuals with mental retardation

Professional staff in four state facilities for individuals with mental retardation were surveyed to determine their perceptions, knowledge and opinions regarding the use of psychotropic medication. A large majority of the 377 respondents indicated that the physicians in their facilities were primarily responsible for medication-related decisions. Under ideal conditions, however, all professional staff and parents were seen as having a greater influence in the decision-making process. Aggression, delusions and hallucinations, self-injury, other psychiatric disorders, and anxiety were rated as disorders most likely to result in medication therapy. Behaviour modification was viewed as a suitable alternative to drug treatment for acting out and aggression. The professionals indicated that behavioural observation was the most influential assessment technique in current usage, followed by global impressions and informal diaries. Over 80% of the respondents perceived their preservice and inservice training on issues related to the use of psychotropic medication to treat behaviour problems as inadequate, with 96% of them desiring continuing education. These findings were compared to data from similar studies of populations with other disabilities, and suggestions for modifications in the current decision-making processes related to the use of psychotropic medication in institutionalized individuals with mental retardation are discussed.

Effects of fentanyl administration on respiratory system compliance in infants

OBJECTIVE

To determine if the analgesic doses of fentanyl used in a pediatric intensive care unit (ICU) setting adversely affect dynamic total respiratory system compliance in awake, intubated infants.

DESIGN

Prospective case-control study.

SETTING

Pediatric and pediatric cardiac ICUs of a tertiary university hospital.

PATIENTS

Thirteen awake and mechanically ventilated children < 6 months of age.

INTERVENTIONS

Measurements of dynamic total respiratory system compliance were obtained during steady-state conditions for 6 mins and continued for 10 mins after the rapid, intravenous administration of 4 micrograms/kg of fentanyl. No patient had received a narcotic, benzodiazepine, or muscle relaxant within the previous 4 hrs.

MEASUREMENTS AND MAIN RESULTS

After fentanyl administration, dynamic total respiratory system compliance was unchanged in three patients, improved in nine patients, and deteriorated in one patient. The mean value for the entire group increased from 0.76 mL/cm H2O/kg before infusion to 0.82 mL/cm H2O/kg after infusion (p < .02), representing a 9.6% increase. None of the patients showed oxygen desaturation as assessed by continuous pulse oximeter, or episodes of chest wall rigidity.

CONCLUSIONS

This work corroborates our clinical impression that rapid infusions of fentanyl at the dose tested in small infants do not adversely affect dynamic total respiratory system compliance. To the contrary, the sedating and analgesic effects may improve synchronous breathing and decrease voluntary muscle tone, resulting in improved dynamic total respiratory system compliance.