Ex-vivo mucolytic and anti-inflammatory activity of BromAc in tracheal aspirates from COVID-19

COVID-19 is a lethal disease caused by the pandemic SARS-CoV-2, which continues to be a public health threat. COVID-19 is principally a respiratory disease and is often associated with sputum retention, for which there are limited therapeutic options. In this regard, we evaluated the use of BromAc, a combination of Bromelain and Acetylcysteine (NAC). Both drugs present mucolytic effect and have been studied to treat COVID-19. Therefore, we sought to examine the mucolytic, antiviral, and anti-inflammatory effect of BromAc in tracheal aspirate samples from critically ill COVID-19 patients requiring mechanical ventilation. Method: Tracheal aspirate samples from COVID-19 patients were collected following next of kin consent and mucolysis, rheometry and cytokine storm analysis was performed. Results: BromAc displayed a robust mucolytic effect in a dose dependent manner. BromAc showed anti-inflammatory activity, reducing the action of cytokine storm, chemokines including MIP-1alpha, CXCL8, MIP-1b, MCP-1 and IP-10, and regulatory cytokines IL-5, IL-10, IL-13 IL-1RA and total reduction for IL-9 compared to NAC alone and control. BromAc acted on IL-6, demonstrating a reduction in G-CSF and VEGF-D at concentrations of 125 and 250ug. Conclusion: These results indicate robust mucolytic and anti-inflammatory effect of BromAc in tracheal aspirates from critically ill COVID-19 patients, indicating its potential as a therapeutic strategy to COVID-19.

Microbiological profiles of tracheostomy patients: a single-center experience

Background: This study compared the prevalence of common microorganisms in obstructed and non-obstructed cases across the four quarters on the first post-tracheostomy year.Methods: A retrospective chart review of the microbiological profiles of all adult patients who underwent a tracheostomy was conducted between June 2015 and September 2019 at our hospital. Based on the tracheostomy indications, patients were allocated to obstructed or non-obstructed group. Any patient with at least one positive sample was followed up quarterly for a year. The first culture result obtained was recorded at least one month following the last antibiotic dose in each quarter.Results: Out of the 65 tracheal aspirate results obtained from 58 patients (mean age, 57.5±16.48 years), the most common procedure and indications were surgical tracheostomy (72.4%) and non-obstructed causes (74.1%), respectively. Moreover, 47.7% of the culture results indicated Pseudomonas aeruginosa, which showed significantly different proportions across the quarters (p=0.006). Among obstructed patients, P. aeruginosa was the most common (35%), followed by methicillin-resistant Staphylococcus aureus (MRSA; 23.5%).Conclusions: The most common post-tracheostomy microorganism was P. aeruginosa. MRSA showed a strong association with tracheostomy for obstructive indications.

Pediatric surgical sepsis: diagnostics and intensive therapy

The aim: Optimization of diagnostics and schemes of pathogenetic intensive therapy of surgical sepsis in children based on clinical and laboratory criteria and bacteriological monitoring. Materials and methods: The research period is 2018-2020. The object of the study (n=73) – children with surgical pathology (widespread peritonitis, bacterial destruction of the lungs, post-traumatic brain hematomas, abdominal trauma, etc.). Research methods: microbiological monitoring to determine the sensitivity of the microorganism to antibiotics was carried out before and at the stages of treatment (sputum, urine, wound, bronchoalveolar lavage, tracheal aspirate, blood, contents from drainages, wound surface). Determination of the sensitivity of the isolated strains to antibiotics was carried out by the disk-diffusion method. To determine predictors of sepsis in surgical patients, clinical (mean arterial pressure (mAP), heart rate (HR), respiratory rate (RR), SpO2, etc. and laboratory parameters on days 1–2 (up to 48 hours) of sepsis identification, days 4 and 8 of intensive therapy. Procalcitonin was determined by immunofluorescence on a Triage® MeterPro analyzer (Biosite Diagnostics, USA). Blood gases and electrolytes were analyzed using a Stat Profile CCX analyzer (Nova Biomedical, USA). Results: studies have shown the effectiveness of complex intensive care in 86.3 % of cases. Mortality was found in 13.7 % of cases. Patients with severe surgical pathology died: widespread peritonitis, severe TBI + coma with irreversible neurological disorders, urosepsis against the background of chronic renal failure, after repeated surgical interventions, due to the development of refractory septic shock (SS). Conclusions. Early diagnosis of sepsis, rational early ABT under the control of microbiological monitoring, non-aggressive infusion therapy with early prescription of vasopressors (SS) with constant monitoring of the child's main life support organs contribute to an improvement in sepsis outcomes and a decrease in mortality

Viral loads in nasopharyngeal aspirates and tracheal aspirates among children hospitalized with invasive ventilation for human adenovirus pneumonia

Purpose To evaluate viral loads in children with human adenovirus (HAdV) pneumonia at different stages of disease and compare the viral load between upper and lower respiratory tract samples. Methods We prospectively enrolled children who required invasive ventilation for HAdV pneumonia. Nasopharyngeal aspirate (NPA) and tracheal aspirate (TA) samples were collected throughout the entire period of invasive ventilation. Viral detection and quantification were performed using quantitative real-time polymerase chain reaction. Results Ninety-four children were enrolled. The median age of the children was 12.0 months (IQR: 11.0–24.0), and > ninety percent of patients were aged between 6 and 59 months. Seven hundred and nine paired NPA-TA samples were collected. The median viral loads of the NPA and TA samples were 7.31 log10 and 7.50 log10 copies/mL, respectively. Viral loads generally decreased steadily over time. The median viral load after 1, 2, 3, and > 3 weeks of the disease course was 8.65, 7.70, 6.69, and 5.09 log10 copies/mL, respectively, in NPA samples and 8.67, 7.79, 7.08, and 5.53 log10 copies/mL, respectively, in TA samples. Viral load showed a significant negative correlation with time since symptom onset in both NPA samples (Spearman r = − 0.607, P = 0.000) and TA samples (Spearman r = − 0.544, P = 0.000). The predicted duration of HAdV shedding was 60.17 days in the NPA group and 65.81 days in the TA group. Viral loads in NPA and TA from the same subjects correlated well with each other (R2 = 0.694). HAdV loads in NPA and TA were most comparable during the early phase of infection (95% limits of agreement, − 1.36 to 1.30 log10 copies/mL, R2 = 0.746). Variation increased during the late phase of infection (i.e., in follow-up samples), with viral loads remaining significantly higher in TA than NPA. Conclusions In children with HAdV pneumonia, viral loads in both NPA and TA steadily decreased during the course of the disease, and the predicted duration of viral shedding was more than 2 months. The HAdV DNA load of NPA is highly correlated with that of TA, especially in the initial phase of infection.

Cluster analysis and profiling of airway fluid metabolites in pediatric acute hypoxemic respiratory failure

Hierarchal clustering of amino acid metabolites may identify a metabolic signature in children with pediatric acute hypoxemic respiratory failure. Seventy-four immunocompetent children, 41 (55.4%) with pediatric acute respiratory distress syndrome (PARDS), who were between 2 days to 18 years of age and within 72 h of intubation for acute hypoxemic respiratory failure, were enrolled. We used hierarchal clustering and partial least squares-discriminant analysis to profile the tracheal aspirate airway fluid using quantitative LC–MS/MS to explore clusters of metabolites that correlated with acute hypoxemia severity and ventilator-free days. Three clusters of children that differed by severity of hypoxemia and ventilator-free days were identified. Quantitative pathway enrichment analysis showed that cysteine and methionine metabolism, selenocompound metabolism, glycine, serine and threonine metabolism, arginine biosynthesis, and valine, leucine, and isoleucine biosynthesis were the top five enriched, impactful pathways. We identified three clusters of amino acid metabolites found in the airway fluid of intubated children important to acute hypoxemia severity that correlated with ventilator-free days < 21 days. Further studies are needed to validate our findings and to test our models.

1392. Nontuberculous Mycobacteria Isolated from Wisconsin Residents, 2010-2018

Background Wisconsin is one of a handful of states in which laboratory identification of nontuberculous mycobacteria (NTM) from clinical samples is reportable to public health. The aims of this study were to characterize the demographic features of Wisconsin adults with NTM, assess the relative abundance of NTM species recovered, and describe trends in NTM isolation over the study period. Methods We conducted a retrospective cohort study of Wisconsin residents 18 years of age and older from whom NTM isolates were recovered and reported to the Wisconsin Electronic Disease Surveillance System (WEDSS) between 2010 and 2018. Isolates of M. gordonae were excluded. For the analysis of NTM frequency, multiple reports from the same individual were enumerated as separate isolates when non-identical or collected from different sites. Because NTM were usually reported into WEDSS without clinical data, this study couldn’t discern the clinical significance of the isolates. Results A total of 9,032 NTM isolates from 7,722 adults were analyzed. The average annual number of reported NTM cases was 950 (21.7/100,000 adults) during 2011-2018. Table 1 shows the demographic characteristics of individuals with NTM isolates, stratified by specimen collection site and NTM species. M. avium complex (MAC) accounted for 75.7% of respiratory isolates. An important pathogenic NTM, M. xenopi, accounted for 8.9% of non-MAC respiratory isolates. As shown in Table 2, M. chelonae, a rapidly growing mycobacteria (RGM), was the most common species isolated from skin and soft tissue, head, ears, nose and throat, and eye specimens. MAC was the most common isolate from other tissue sites. Table 1. Demographic characteristics of individuals with NTM isolates. Categorization was based upon the initially recovered sample when multiple samples were obtained from a given individual. “Respiratory” samples included sputum, bronchoalveolar lavage, and tracheal aspirate specimens. IQR, interquartile range. RGM, rapidly growing mycobacteria (M. chelonae and the M. abscessus, M. chelonae-abscessus, and M. fortuitum groups). SST, skin and soft tissue. Table 2. Most common NTM species isolated from non-respiratory sites. *’Respiratory specimens’ was inclusive of sputum, bronchoalveolar lavage, and tracheal aspirate specimens. CNS, central nervous system. HENT, head, ears, nose, or throat. SST, skin and soft tissue. Conclusion Consistent with prior studies, MAC is the predominant NTM isolated from respiratory specimens in Wisconsin. RGM are important minority respiratory pathogens, and predominate as skin and soft tissue NTMs. We highlight M. xenopi as an important pathogen in Wisconsin compared to other parts of the United States. In contrast to recent reports of increasing incidence of NTM disease, we found a stable annual incidence of NTM isolation between 2010 and 2018. Disclosures All Authors: No reported disclosures

1139. Reducing Collection of Tracheal Aspirate Bacterial Cultures: A Diagnostic Test Stewardship Intervention

Background Tracheal aspirate (TA) bacterial cultures are often collected in mechanically ventilated children to evaluate for ventilator-associated infections (VAI), including tracheitis and pneumonia. However, frequent bacterial colonization of tracheal tubes results in poor specificity of positive TA cultures for distinguishing bacterial infection from colonization, which contributes to antibiotic overuse for VAI. We performed a quality improvement project to reduce collection of TA cultures through implementation of a consensus guideline to standardize culture ordering, and measured its impact on antibiotic use in a tertiary PICU. Methods A multidisciplinary team including PICU, pulmonary, and ID clinicians developed the consensus guideline in November 2019-February 2020. The first Plan-Do-Study-Act (PDSA) cycle occurred in August 2020 and included provider education, providing a link to the guideline in the TA culture order, and signs and screensavers highlighting key guideline recommendations. The second PDSA cycle occurred in October-December 2020 and included weekly emails to on service PICU clinicians. Statistical process control charts were used to measure the number of TA cultures collected/100 ventilator days and broad-spectrum antibiotic DOT/100 ventilator days. The number of patients treated for VAI/100 ventilator days and guideline compliance were also measured. Results The baseline rate of TA culture collection was 4.58/100 ventilator days. A centerline shift to 3.33 cultures/100 ventilator days occurred in March 2020. Following PDSA 1 and 2 in October 2020, a second downward centerline shift to 2.22 cultures/100 ventilator days occurred (Figure 1). Broad-spectrum antibiotic days of therapy/100 ventilator days decreased in November 2019 coincident with the start of the project, but no further reductions occurred after PDSA 1 and 2 (Figure 2). The number of patients treated for VAI decreased from a baseline of 1.24/100 ventilator days to 0.66/100 ventilator days. Finally, the proportion of TA cultures ordered that were non-compliant with the guideline recommendations was unchanged throughout the study period (Table 1). Conclusion A consensus guideline reduced collection of TA cultures, with a modest reduction in the rate of antibiotic treatment for VAI. Disclosures All Authors: No reported disclosures

1285. Identification of KPC Omega Loop Variant R163S Conferring Ceftazidime-Avibactam Resistance

Background We report on a 56 year-old male with prolonged COVID-19 pneumonia who initially improved with dexamethasone and intubation but quickly decompensated. Clinical and radiologic features were consistent with VAP. Tracheal aspirate cultures grew carbapenem-resistant Enterobacter cloacae; meropenem (MEM) MIC was &gt;8 ug/ml (resistant) while ceftazidime-avibactam (CZA) MIC was 2/4 ug/ml (susceptible). Lateral flow antigen assay detected a KPC enzyme. The patient was treated with CZA with steady improvement in respiratory function over the next two weeks. He then experienced an episode of tachycardia, prompting repeat culture. At this point the patient had been extubated: sputum culture grew KPC+ E. cloacae that now showed CZA-resistance (MIC &gt;8/4 ug/ml) and paradoxical decrease in MEM MIC (4 ug/ml); meropenem-vaborbactam (&lt; 2/8 ug/ml) was susceptible. Methods The pre- & post-CZA therapy E. cloacae isolates underwent whole genome sequencing using the Illumina 150bp paired end protocol; sequences were quality trimmed and compared. Results A point mutation in the plasmid blaKPC3 gene was identified in the post-CZA therapy isolate, an R163S mutation in the omega loop of the enzyme. ompC and ompF porin genes were analyzed to rule-out decreased influx as a mechanism for CZA-resistance: the pre- and post-CZA isolates had identical porin sequences. Conclusion This case highlights emerging mutations within KPC carbapenemases that lead to resistance to ‘last-line’ antimicrobials like CZA. The presumptive mechanism is increased KPC active site promiscuity due to increased omega loop flexibility, allowing increased ceftazidime binding and hydrolysis, and decreased avibactam binding and beta lactamase inhibition. Paradoxically, MEM susceptibility improves after such omega loop mutations, likely due to decreased active site binding affinity, a ‘seesaw’ effect between MEM and CZA. While authors have reported MEM MICs falling into the ‘susceptible’ category after an omega loop variant, these bacteria invariably develop secondary mutations leading to MEM treatment failure. Fortunately, given our patient’s improved respiratory status, the post-CZA E. cloacae isolate was felt to reflect colonization and the patient was discharged home without antimicrobial therapy. Disclosures Romney Humphries, PhD D(ABMM), Accelerate Diagnostics (Individual(s) Involved: Self): Consultant, Shareholder; IHMA (Individual(s) Involved: Self): Consultant; Melinta (Individual(s) Involved: Self): Consultant; Momentum (Individual(s) Involved: Self): Grant/Research Support; Pattern (Individual(s) Involved: Self): Consultant; QPex (Individual(s) Involved: Self): Consultant; ThermoFisher (Individual(s) Involved: Self): Consultant; Torus (Individual(s) Involved: Self): Consultant

Pepsin A in Tracheal Secretions From Patients Receiving Mechanical Ventilation

Background In patients in the intensive care unit (ICU) receiving mechanical ventilation, aspiration of gastric contents may lead to ventilator-associated events and other adverse outcomes. Pepsin in pulmonary secretions is a biomarker of microaspiration of gastric contents. Objectives To evaluate the association between tracheal pepsin A and clinical outcomes related to ventilator use. Methods A subset of 297 patients from a larger clinical trial on aspiration of oral secretions in adults receiving mechanical ventilation consented to have pepsin A measured in their tracheal aspirate samples. A concentration ≥6.25 ng/mL indicated a positive result. Abundant microaspiration was defined as pepsin A in ≥30% of samples. Statistical analyses included analysis of variance, analysis of covariance, and χ2 tests. Results Most patients were White men, mean age 59.7 (SD, 18.8) years. Microaspiration was found in 43.8% of patients (n = 130), with abundant microaspiration detected in 17.5% (n = 52). After acuity was controlled for, patients with tracheal pepsin A had a longer mechanical ventilation duration (155 vs 104 hours, P &lt; .001) and ICU stay (9.9 vs 8.2 days, P = .04), but not a longer hospital stay. Conclusions Microaspiration of gastric contents occurred in nearly half of patients and was associated with a longer duration of mechanical ventilation and a longer stay in the ICU. Additional preventative interventions beyond backrest elevation, oropharyngeal suctioning, and management of endotracheal tube cuff pressure may be needed. Also, the timing of pepsin measurements to capture all microaspiration events requires additional exploration.

Dexamethasone Alters Tracheal Aspirate T-Cell Cytokine Production in Ventilated Preterm Infants

Postnatal corticosteroids improve respiratory status and facilitate respiratory support weaning in preterm infants with bronchopulmonary dysplasia (BPD). Older literature describes characteristic cytokine profiles in tracheal aspirates (TA) of BPD patients which are altered with corticosteroids. Corticosteroids also influence peripheral blood T-cell presence. However, little is known regarding TA T-cell phenotype and cytokine production before or after exogenous corticosteroids. We hypothesized that postnatal dexamethasone alters the TA T-cell cytokine profiles of preterm infants. TA samples were collected from 14 infants born from 23 0/7 to 28 6/7 weeks who were mechanically ventilated for at least 14 days. Samples were collected up to 72 h before a ten-day dexamethasone course and again 1 to 3 calendar days after dexamethasone initiation. The primary outcome was change in T cell populations present in TA and their intracellular cytokine profile after dexamethasone treatment, ascertained via flow cytometry. Following dexamethasone treatment, there were significant decreases in respiratory severity score (RSS), percent CD4+IL-6+ cells, CD8+IL-6+ cells, CXCR3+IL-6+ cells, and CXCR3+IL-2+ cells and total intracellular IFN-γ in TA. RSS significantly correlated with TA percent CD4+IL-6+ cells. To our knowledge, this is the first study demonstrating that dexamethasone reduced T-cell IL-6 and this reduction was associated with improved RSS in pre-term infants with evolving BPD.