Multidrug resistant organisms (MDROs) are not associated with greater severity of ventilator associated tracheitis (VAT) in critically-ill pediatric patients

Abstract Corresponding author: Evin Feldman, MD: 269-01 76th Ave, Queens, NY 11040. (718) 470-3350. E-mail: [email protected] Alternate corresponding author: Mundeep Kainth, DO, MPH, 269-01 76th Ave, Queens, NY 11040. (718) 470-3480. Email: [email protected] No conflicts of interest. Background Treatment of suspected ventilator associated infections (VAIs), such as ventilator associated tracheitis (VAT), accounts for nearly half of Pediatric Intensive Care Unit (PICU) antibiotic use and contributes to multidrug resistance organism (MDRO) acquisition. The presence of MDROs in respiratory cultures leads to more antibiotic usage. We sought to understand the baseline MDRO burden of respiratory cultures obtained in our PICU, and specifically identify how MDROs are implicated in VAT clinical phenotype and severity. Methods A retrospective chart review was performed of all respiratory cultures taken from patients with artificial airways in the PICU at a single-center urban tertiary care children’s hospital in the United States from September 2021 to June 2023. Patients with cystic fibrosis were excluded. Demographic factors and respiratory culture results were collected. Definitions of MDROs were adapted from the Centers for Disease Control and Prevention. Instances of VAT and their clinical presentations were identified through chart review, and severity score calculations were performed at the time of culture acquisition. Results Five-hundred and sixty-three respiratory cultures were included during the specified study period. Ninety-nine of these cultures yielded 114 MDROs - a rate of 20.2 MDROs per 100 respiratory cultures sent. Most of these cultures with MDROs were treated for a respiratory infection – 42.4% for VAT, 19.2% for pneumonia. MDROs were more commonly identified in cultures taken from female and African-American subjects (Table 1). S. maltophila and extended spectrum β-lactamase (ESBLs) producing Enterobacteriaceae were the most commonly identified MDROs (Figure 1). One-hundred and nine instances of VAT were identified, with 42 (38.5%) of them involving a MDRO as a causative organism. Instances of VAT involving a MDRO did not have a different rate of abnormal temperature, leukocytosis or leukopenia, increased secretion quantity, increase in baseline ventilator settings, or microscopic purulence (Table 2). Instances of VAT involving a MDRO did not have a higher mortality risk, severity of hypoxemic respiratory failure, or vasoactive support need (Table 2). Conclusions MDROs are often identified in respiratory cultures sent from our PICU, and a substantial portion of VAT is associated with a MDRO. However, VAT caused by a MDRO was not associated with a differing clinical presentation or more severe clinical phenotype. This calls for further investigation into the practice of initiating or escalating antibiotics for VAT solely based on the presence of a MDRO. Table 1. Population Characteristics. Comparison made between subjects with tracheal aspirate cultures with and without growth of MDRO p values <0.05 were considered to be statistically significant. MDRO = multidrug resistant organism. IQR = interquartile range Table 2. Clinical Features of Ventilator Associated Tracheitis. Comparison made between instances of VAT involving and not involving treatment of a MDRO. p values <0.05 were considered to be statistically significant. VAT = Ventilator Associated Tracheitis. MDRO = multidrug resistant organism. WBC = white blood cell. OSI = Oxygenation-Saturation Index. VIS = Vasoactive-Inotropic Score. PIM3 = Pediatric Index of Mortality3.