Positive Respiratory Cultures Research Articles

Association between Ureaplasma colonization and bronchopulmonary dysplasia defined by different criteria in very low birth weight infants: A retrospective cohort study.

To study the association between Ureaplasma colonization and bronchopulmonary dysplasia (BPD) with different definitions in very low birth weight (VLBW) infants. A retrospective cohort study was performed with VLBW infants admitted from January 2019 to October 2021. Neonates with a positive respiratory tract Ureaplasma culture were included in the study group. Control group infants, matched for gestational age (±1 week), birth weight (±100 g), and birth year, had a negative respiratory tract Ureaplasma culture during the same period. The primary outcomes included the incidence and severity of BPD, defined by various criteria. The study included 302 neonates (151 in the study group and 151 in the control group). After adjusting for confounders, Ureaplasma colonization was not associated with BPD as defined by the National Institutes of Health (NIH) in 2001 (adjusted odds ratio [aOR]: 0.820, 95% confidence interval [CI]: 0.362-1.860, p = .635). However, it was associated with BPD as defined by the NIH in 2018 (aOR: 2.490, 95% CI: 1.128-5.497, p = .024) and the Neonatal Research Network (NRN) in 2019 (aOR: 2.352, 95% CI: 1.077-5.134, p = .032). Additionally, VLBW infants with Ureaplasma colonization had a higher risk of moderate-severe BPD according to the NIH 2001 (aOR: 2.352, 95% CI: 1.077-5.134, p = .032), NIH 2018 (aOR: 6.339, 95% CI: 1.686-23.836, p = .006), and NRN 2019 definitions (aOR: 3.542, 95% CI: 1.267-9.904, p = .016). Ureaplasma colonization is not associated with BPD by the NIH 2001 definition, but is associated with an increased incidence by the NIH 2018 or NRN 2019 definitions.

Exposures and coexisting conditions in pediatric nodular tracheobronchitis.

The aim of our study was to investigate the prevalence of coexisting conditions and exposures in children with nodular tracheobronchitis diagnosed by flexible bronchoscopy. We conducted a single-center retrospective review of 100 children diagnosed with nodular tracheobronchitis by flexible bronchoscopy between 2012 and 2023. Common coexisting diagnoses included gastroesophageal reflux disease (GERD, 50%), dysphagia/aspiration (40%), asthma (30%), recurrent croup (30%), tracheostomy dependence (19%) and eosinophilic esophagitis (EOE) (12%). Bronchoalveolar lavage (BAL) demonstrated cellular inflammation with elevated proportions of neutrophils in 63%, and lymphocytes in 24%. Among 88 patients in whom bacterial cultures were performed, 52% were positive, with Moraxella, Haemophilus, Streptococcal and Pseudomonas species predominating. Among 30 patients who underwent viral testing, 57% were positive, with rhinovirus (82%) and adenovirus (29%) predominating. Patients with neutrophilic inflammation were more likely to have a positive respiratory bacterial culture and/or viral polymerase chain reaction (p = 0.003, 0.005). Evaluation of the gastrointestinal tract included 79 patients with a history of esophagogastroduodenoscopy, 45 patients with a videofluoroscopic swallow study (VFSS), and 45 patients with multi-channel intraluminal impedance and pH testing. The majority of VFSS were abnormal (60%) demonstrating either laryngeal penetration (33%) or intratracheal aspiration (27%). Median pH reflux and impedance proximal reflux indices were 3.8% and 0.5% respectively. Potential contributing factors in the pathophysiology of nodular tracheobronchitis include bacterial and viral infections, GERD, dysphagia/aspiration, and EOE. When nodular tracheobronchitis is observed during bronchoscopy, further evaluation to assess for these conditions should be considered.

Patient factors associated with positive respiratory cultures following tracheostomy in pediatric patients

ObjectivesAn increasing number of pediatric patients undergo tracheostomy placement annually. Despite advances in care, these patients remain at high risk for postoperative complications, including respiratory infections. The risk factors for positive respiratory cultures and the impact of culture positivity on overall morbidity and mortality in this population is not fully characterized. Study design and settingRetrospective cross-sectional analysis of all patients within a single tertiary care institution who underwent tracheostomy placement from January 1, 2019 to 12/31/2021. MethodsWe collected patient demographic information, comorbidities, primary indication for tracheostomy placement, and respiratory culture information preoperatively and postoperatively. The primary outcome measure was positive bacterial respiratory culture with speciation within 1, 3, or 6 months of tracheostomy placement. The secondary outcome measure was all-cause mortality within the study period. ResultsA total of 180 patients with median (IQR) age of 5.2 (3.4–31.0) months at time of tracheostomy placement were included in the study. Nearly half of patients had a positive culture within 1 month (n = 81,47.4 %) while 63.7 % of patients were positive within 6 months of tracheostomy placement (n = 109). Risk factors included respiratory and/or cardiac comorbidities. Positive respiratory cultures within 6 months of surgery and cardiac and/or neurologic comorbidities were associated with increased all-cause mortality following tracheostomy placement. ConclusionsPositive respiratory cultures are common following tracheostomy placement, more so in patients with cardiac and pulmonary comorbid conditions. Positive cultures are associated with increased all-cause mortality. More work is necessary to determine optimal screening frequency and treatment protocols for positive cultures in this population.

Clinical significance of lower respiratory tract culture within 48 h of admission in patients with viral pneumonia: an observational study

BackgroundThe aim of this retrospective study was to examine the risk factors of positive lower respiratory tract cultures and to investigate whether nosocomial infections are common in patients with positive lower respiratory tract cultures.MethodsWe enrolled 86 patients diagnosed with influenza A-related critical illness who were treated at Fuzhou Pulmonary Hospital of Fujian in China between 1st October 2013 and 31st March 2019. The of admission were used to divide the enrolled patients into two groups. Sputum and bronchoalveolar lavage fluid specimens were collected within 48 h after admission for culture. All samples were cultured immediately after sampling. Nosocomial infections are defined as any symptom or sign of pulmonary infiltration, confirmed by X-ray, after 5 days of admission and positive results from one or more cultures.ResultsThe average age of this cohort was (54.13 ± 16.52) years. Based on the culture results, Staphylococcus aureus and Candida albicans had the highest positive rates (3.40% (3/86) and 20.90% (18/86), respectively). In patients with positive lower respiratory tract cultures, the incidence of nosocomial infection was 73.30% (22/30) five days after admission. However, the incidence of nosocomial infection was lower (42.80%, 24/56) in patients with negative lower respiratory tract cultures. Hemoptysis, systolic pressure at admission, and blood urea nitrogen level at admission were all independent risk factors for positive lower respiratory tract cultures within 48 h of admission.ConclusionOur data showed that a significant proportion of patients with pneumonia exhibited co-infections with bacteria or fungi within five days of hospital admission. Hemoptysis, systolic pressure, and blood urea nitrogen levels at admission emerged as the key risk factors. These findings underscore the necessity of closely monitoring patients with influenza infection, particularly for positive bacterial or fungal cultures within the initial 48 h of admission.

Factors associated with tracheostomy-associated infection treatment: A multicenter observational study.

To characterize factors that influence the decision to treat suspected pediatric bacterial tracheostomy-associated respiratory infections (bTRAINs; e.g., pneumonia, tracheitis). We conducted a multicenter, prospective cohort study of children with pre-existing tracheostomy hospitalized at six children's hospitals for a suspected bTRAIN (receipt of respiratory culture plus ≥1 doses of an antibiotic within 48 h). The primary predictor was respiratory culture growth categorized as Pseudomonas aeruginosa, P. aeruginosa + ≥1 other bacterium, other bacteria alone, or normal flora/no growth. Our primary outcome was bTRAIN treatment with a complete course of antibiotics as documented by the discharge team. We used logistic regression with generalized estimating equations to identify the association between our primary predictor and outcome and to identify demographic, clinical, and diagnostic testing factors associated with treatment. Of the 440 admissions among 289 patients meeting inclusion criteria, 307 (69.8%) had positive respiratory culture growth. Overall, 237 (53.9%) of admissions resulted in bTRAIN treatment. Relative to a negative culture, a culture positive for P. aeruginosa plus ≥1 other organism (adjusted odds ratio [aOR] 2.3; 95% confidence interval [CI] 1.02-5.0)] or ≥1 other organism alone (aOR: 2.8; 95% CI: 1.4-5.6)] was associated with treatment. Several clinical and diagnostic testing (respiratory Gram-stain and chest radiograph) findings were also associated with treatment. Positive respiratory viral testing was associated with reduced odds of treatment (aOR: 0.5; 95% CI: 0.2-0.9). Positive respiratory cultures as well as clinical indicators of acute illness and nonculture test results were associated with bTRAIN treatment. Clinicians may be more comfortable withholding antibiotics when a virus is identified during testing.

Prevalence of Bacterial Codetection and Outcomes for Infants Intubated for Respiratory Infections.

To determine the prevalence of respiratory bacterial codetection in children younger than 2 years intubated for acute lower respiratory tract infection (LRTI), primarily viral bronchiolitis, and identify the association of codetection with mechanical ventilation duration. Prospective observational study evaluating the prevalence of bacterial codetection (moderate/heavy growth of pathogenic bacterial plus moderate/many polymorphonuclear neutrophils) and the impact of codetection on invasive mechanical ventilation (IMV) duration. PICUs in 12 high and low/middle-income countries. Children younger than 2 years old requiring intubation and ICU admission for LRTI and who had a lower respiratory tract culture obtained at the time of intubation between December 1, 2019, and November 30, 2020. None. Of the 472 analyzed patients (median age 4.5 mo), 55% had a positive respiratory culture and 29% ( n = 138) had codetection. 90% received early antibiotics starting at a median of 0.36 hours after respiratory culture. Median (interquartile range) IMV duration was 151 hours (88, 226), and there were 28 deaths (5.3%). Codetection was more common with younger age, a positive respiratory syncytial virus test, and an admission diagnosis of bronchiolitis; it was less common with an admission diagnosis of pneumonia, with admission to a low-/middle-income site, and in those receiving vasopressors. When adjusted for confounders, codetection was not associated with longer IMV duration (adjusted relative risk 0.854 [95% CI 0.684-1.065]). We could not exclude the possibility that codetection might be associated with a 30-hour shorter IMV duration compared with no codetection, although the CI includes the null value. Bacterial codetection was present in almost a third of children younger than 2 years requiring intubation and ICU admission for LRTI, but this was not associated with prolonged IMV. Further large studies are needed to evaluate if codetection is associated with shorter IMV duration.

Clinical characteristics, bacterial coinfections and outcomes in COVID-19-associated pulmonary aspergillosis in a third-level Mexican hospital during the COVID-19 pre-vaccination era.

Damage due to respiratory viruses increases the risk of bacterial and fungal coinfections and superinfections. High rates of invasive aspergillosis are seen in severe influenza and COVID-19. This report describes CAPA cases diagnosed during the first wave in the biggest reference centre for severe COVID-19 in Mexico. To describe the clinical, microbiological and radiological characteristics of patients with invasive pulmonary aspergillosis associated with critical COVID-19, as well as to describe the variables associated with mortality. This retrospective study identified CAPA cases among individuals with COVID-19 and ARDS, hospitalised from 1 March 2020 to 31 March 2021. CAPA was defined according to ECMM/ISHAM consensus criteria. Prevalence was estimated. Clinical and microbiological characteristics including bacterial superinfections, antifungal susceptibility testing and outcomes were documented. Possible CAPA was diagnosed in 86 patients among 2080 individuals with severe COVID-19, representing 4.13% prevalence. All CAPA cases had a positive respiratory culture for Aspergillus species. Aspergillus fumigatus was the most frequent isolate (64%, n = 55/86). Seven isolates (9%, n = 7/80) were resistant to amphotericin B (A. fumigatus n = 5/55, 9%; A. niger, n = 2/7, 28%), two A. fumigatus isolates were resistant to itraconazole (3.6%, n = 2/55). Tracheal galactomannan values ranged between 1.2 and 4.05, while serum galactomannan was positive only in 11% (n = 3/26). Bacterial coinfection were documented in 46% (n = 40/86). Gram negatives were the most frequent cause (77%, n = 31/40 isolates), from which 13% (n = 4/31) were reported as multidrug-resistant bacteria. Mortality rate was 60% and worse prognosis was seen in older persons, high tracheal galactomannan index and high HbA1c level. One in 10 individuals with CAPA carry a resistant Aspergillus isolate and/or will be affected by a MDR bacteria. High mortality rates are seen in this population.

Mortality in hospitalized SARS-CoV-2 patients with contemporaneous bacterial and fungal infections.

The interplay between SARS-CoV-2 and contemporaneous bacterial or fungal culture growth may have crucial implications for clinical outcomes of hospitalized patients. This study aimed to quantify the effect of microbiological culture positivity on mortality among hospitalized patients with SARS-CoV-2. In this retrospective cohort study, we included adult hospitalized patients from OPTUM COVID-19 specific data set, who tested positive for SARS-CoV-2 within 14 days of hospitalization between 01/20/2020 and 01/20/2022. We examined outcomes of individuals with organisms growing on cultures from the bloodstream infections (BSIs), urinary tract, and respiratory tract, and a composite of the three sites. We used propensity score matching on covariates included demographics, comorbidities, and hospitalization clinical parameters. In a sensitivity analysis, we included same covariates but excluded critical care variables such as length of stay, intensive care unit stays, mechanical ventilation, and extracorporeal membrane oxygenation. The cohort included 104,560 SARS-CoV-2 positive adult hospitalized patients across the United States. The unadjusted mortality odds increased significantly with BSIs (98.7%) and with growth on respiratory cultures (RC) (176.6%), but not with growth on urinary cultures (UC). Adjusted analyses showed that BSIs and positive RC independently contribute to mortality, even after accounting for critical care variables. In SARS-CoV-2-positive hospitalized patients, positive bacterial and fungal microbiological cultures, especially BSIs and RC, are associated with an increased risk of mortality even after accounting for critical care variables associated with disease severity. These findings underscore the importance of stringent infection control and the effective management of secondary infections to improve patient outcomes.

Donor blood cultures and outcomes after lung transplantation: a single-center report.

Transplanting lungs from donors with positive blood cultures has not been shown to adversely affect survival. There is limited evidence for potential effects on other outcomes, such as hospital course, graft function, and transmission of infection. This retrospective cohort study included adult patients who underwent lung-only transplantation for the first time between March 2010 and December 2022. Outcomes of patients whose donors had positive blood cultures within 72h of transplant were compared to patients whose donors had negative blood cultures. Twenty-five (10.8%) of 232 donors had positive blood cultures, including a single, unexpected case with candidemia. The most commonly isolated bacteria were Enterobacter cloacae (n=5), Klebsiella pneumoniae (n=5), Acinetobacter baumannii (n=3), Pseudomonas aeruginosa (n=3), and Staphylococcus aureus (n=3). Eleven donors had identical bacteria in their respiratory cultures. All patients who were transplanted from donors with positive blood cultures survived beyond 90 days. Positive donor blood cultures were not associated with longer hospital stay, in-hospital complications, acute cellular rejection, or the achievement of 80% predicted forced expiratory volume in the first second. Probable transmission of donor bacteremia occurred in only two cases (both with S. aureus). These two donors had positive respiratory cultures with the same organism. The study did not find an increased risk of adverse events when transplanting lungs from donors with positive blood cultures. Allograft cultures may be more predictive of the risk of transmitting infections.

A quasi-experimental study of a bundled diagnostic stewardship intervention for ventilator-associated pneumonia

ObjectivesDiagnostic error in the use of respiratory cultures for ventilator-associated pneumonia (VAP) fuels misdiagnosis and antibiotic overuse within intensive care units. In this prospective quasi-experimental study (NCT05176353), we aimed to evaluate the safety, feasibility, and efficacy of a novel VAP-specific bundled diagnostic stewardship intervention (VAP-DSI) to mitigate VAP over-diagnosis/overtreatment. MethodsWe developed and implemented a VAP-DSI using an interruptive clinical decision support tool and modifications to clinical laboratory workflows. Interventions included gatekeeping access to respiratory culture ordering, preferential use of non-bronchoscopic bronchoalveolar lavage for culture collection, and suppression of culture results for samples with minimal alveolar neutrophilia. Rates of adverse safety outcomes, positive respiratory cultures, and antimicrobial utilization were compared between mechanically ventilated patients (MVPs) in the 1-year post-intervention study cohort (2022–2023) and 5-year pre-intervention MVP controls (2017–2022). ResultsVAP-DSI implementation did not associate with increases in adverse safety outcomes but did associate with a 20% rate reduction in positive respiratory cultures per 1000 MVP days (pre-intervention rate 127 [95% CI: 122–131], post-intervention rate 102 [95% CI: 92–112], p < 0.01). Significant reductions in broad-spectrum antibiotic days of therapy per 1000 MVP days were noted after VAP-DSI implementation (pre-intervention rate 1199 [95% CI: 1177–1205], post-intervention rate 1149 [95% CI: 1116–1184], p 0.03). DiscussionImplementation of a VAP-DSI was safe and associated with significant reductions in rates of positive respiratory cultures and broad-spectrum antimicrobial use. This innovative trial of a VAP-DSI represents a novel avenue for intensive care unit antimicrobial stewardship. Multicentre trials of VAP-DSIs are warranted.

2240. Breaking Dogmas: A Single Center Evaluation of Empiric Vancomycin Use Among Intensive Care Unit Patients with Suspected Pneumonia, Bacteremia or Sepsis

Abstract Background Augmented concern for methicillin-resistant Staphylococcus aureus (SA) infections in intensive care units (ICU) has led to increased empiric vancomycin use (EVU) in patients with suspected pneumonia, bacteremia, and/or sepsis. At Tufts Medical Center, vancomycin is prescribed at clinician discretion without restrictions. We aimed to evaluate the impact of cultures on EVU and identify predictors associated with prolonged EVU among ICU patients with cultures negative (CN) for SA. Methods A retrospective study from April 2022 to January 2023 of ICU adult patients with EVU for suspected pneumonia, bacteremia, or sepsis was conducted. ICU service, length of stay (LOS), duration of EVU, blood &amp; respiratory cultures, mechanical ventilation (MV), central line presence, and vasopressor use were collected. Prolonged EVU was defined as vancomycin use for more than 2 days despite CN for SA. The primary outcome was the rate of prolonged EVU discontinuation. Linear regression included demographics, ICU service, LOS, indication, Charlson Co-morbidity Index, lactate, MV, and 0.5 mg/dL serum creatinine change. Logistic regression included the same variables plus age, positive respiratory cultures and MV interaction. Results A total of 165 ICU patients had EVU. Of these, 132 (80%) had cultures collected before EVU vs. 33 (20%) that did not. Blood cultures were collected in 117 (88.6%); 66 (49.6%) had respiratory cultures; 51 (38.6%) had both collected. Median vancomycin duration was 2 days (1-3). Prolonged EVU was observed in 47 (46.1%) patients, while 55 (53.9%) had EVU discontinued within 2 days with CN for SA. On average Cardiac Surgery (CS) spent 2 days longer on vancomycin compared to Surgical (p=0.037) and Pulmonary (p=0.01) patients. MV among ICU patients was less likely to be associated with vancomycin discontinuation within 2 days with CN for SA (aOR [adjusted odd ratio] 0.12, 95% CI 0.03, 0.50; p=0.003). Conclusion EVU discontinuation was more likely within 2 days in ICU patients with CN for SA, but less likely for MV or CS patients. In a substantial proportion of patients, cultures were not collected. Our findings highlight the importance of diagnostic testing in ICU settings to help reduce EVU. Disclosures Maureen Campion, PharmD, Shinoigi: Speaker

355. Stratification of Patient-Specific Risk Factors for Multidrug-Resistant Gram-Negative Respiratory Pathogens in Intensive Care Units (ICU)

Abstract Background Guidelines for nosocomial pneumonia recommend empiric combination therapy for patients with a risk of infection due to multidrug-resistant Gram-negative pathogens in ICUs. Common risk factors cited include ≥ 5-day duration in the ICU, transfer from other healthcare facilities, recent antibiotic use, and history of a resistant Gram-negative pathogen. However, the interrelation of these factors and which are key drivers remain ill-defined. This study is designed to stratify risk factors to further optimize empiric regimens. Methods A total of 190 patients who had a positive Gram-negative respiratory culture obtained from the MICU/SICU of Michigan Medicine in 2021 were included. Patients were classified into subgroups based on the presence/absence of each aforementioned risk factor. Cumulative susceptibility percentages of isolates in each risk group were examined and compared. Results Cumulative susceptibility percentages of Gram-negative respiratory isolates from patients with/without each risk factor are shown in Figure 1. Patients with recent antibiotic use or history of a resistant Gram-negative pathogen had noticeably lower susceptibility rates than those without those risk factors, whereas the presence/absence of prolonged ICU stay and/or admission from another facility had minimal impact on susceptibility rates. In patients without recent antibiotic exposure or history of a resistant pathogen, 90% had pathogens that demonstrated in vitro susceptibility to cefepime monotherapy. (Figure 2) In contrast, the susceptibility percentages of any β-lactam monotherapy were &amp;lt; 75% in patients with one or more of these factors and remained &amp;lt; 85% when adding an aminoglycoside or fluoroquinolone. More stratified analyses demonstrated that patients with previous positive carbapenem-resistant P. aeruginosa or Enterobacterales should receive a novel agent. Proposed stratified empiric regimens are summarized in Figure 3. Conclusion Recent antibiotic use and previous positive resistant Gram-negative cultures were significant factors for determining antibiotic resistance in Gram-negative respiratory pathogens. Risk stratification based on these two factors can help further optimize empiric antibiotic therapy. Disclosures jason M. Pogue, PharmD, AbbVie: Advisor/Consultant|Entasis: Advisor/Consultant|Ferring: Advisor/Consultant|GSK: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Qpex: Advisor/Consultant|Shionogi: Advisor/Consultant

1266. Refining Antimicrobial Stewardship by De-escalating Vancomycin Using MRSA (Methicillin Resistant Staphylococcus aureus) Nasal Screening in a Community Hospital Setting

Abstract Background Our institution has prioritized appropriate use of anti-Methicillin-resistant Staphylococcus aureus (MRSA) drugs such as vancomycin. The overuse of anti-MRSA drugs contributes to drug toxicities and development of resistant organisms such as vancomycin-resistant enterococcus (VRE). Recent studies show that MRSA nasal surveillance screening has a high negative predictive value of 96.5% in all types of pneumonia. At our community hospital a decentralized pharmacist-driven MRSA nares screening protocol was novel. We report the results of implementing a MRSA nares screening protocol for vancomycin de-escalation in pneumonia patients. Methods A decentralized pharmacist reviewed patients with a diagnosis of pneumonia and prescribed vancomycin. The pharmacist ensured that a culture-based MRSA nares screen was performed within 48 hours of admission, if not already ordered. If the nares screen returned negative and respiratory cultures did not grow MRSA at 48 hours, the decentralized pharmacist contacted the medical team to recommend discontinuing vancomycin. Reasons for exclusion included a positive respiratory culture for MRSA within the prior 7 days, septic shock, alternative site of MRSA infection, and greater than 48 hours of anti-MRSA therapy at time of swab collection. Results 164 patients were reviewed by pharmacy between 6/16/22 and 4/25/23. 98% of MRSA nares screening had been performed within 48 hours of admission. MRSA screen was ordered by the decentralized pharmacist in 44% of patients. 89% of patients screened were negative for MRSA and reviewed for de-escalation of vancomycin. In 40% of patients, vancomycin was discontinued after recommendations by the decentralized pharmacist, with 95% of the recommendations accepted by the primary hospitalist physician. 37% of patients' vancomycin was discontinued by the attending physician. Overall, 77% of patients with negative MRSA nasal screen results were successfully de-escalated. Conclusion Our data highlights the effectiveness of close physician-pharmacy collaboration. Most nares cultures were negative for MRSA allowing for de-escalation of antibiotics. Pharmacist recommendations were accepted majority of the time. Given the data, we plan to apply this approach for other ongoing stewardship initiatives. Disclosures All Authors: No reported disclosures

90. The Diagnosis of Ventilator-associated pneumonia (DIVA) trial: Results of a Clinical Trial of a Bundled VAP Diagnostic Stewardship Intervention

Abstract Background Ventilator-associated pneumonia (VAP) is commonly overdiagnosed &amp; a primary driver of antibiotic overuse within intensive care units (ICUs). Antimicrobial stewardship programs have successfully leveraged diagnostic stewardship interventions (DSIs) to prevent overdiagnosis/overtreatment of diverse clinical syndromes, yet this approach has not been extended to VAP. In this trial, we aimed to evaluate the safety, feasibility &amp; efficacy of a novel DSI care bundle (DSI-CB) targeting VAP. Methods The DIVA trial (NCT05176353) was a pilot/feasibility trial conducted in 2 ICUs at Michigan Medicine from February 2022-February 2023. A DSI-CB targeting the respiratory culture testing pathway was implemented sequentially in study ICUs, using an interruptive electronic health record clinical decision support tool &amp; modifications to microbiology laboratory workflows (Table 1). Providers were counseled on DSI-CB use during bimonthly educational sessions during trial rollout &amp; via monthly email reminders thereafter. Rates of prespecified co-primary safety and secondary efficacy outcomes were compared between the postintervention study cohort &amp; 5-year preintervention historical controls using negative binomial regression. Interrupted time series analysis was used to evaluate ICU antibiotic utilization rates (ICU-AURs) to account for temporal trends. Results 1810 patients were admitted to study ICUs following DSI-CB implementation, 29% of whom were eligible for DSI-CB use. DSI-CB was utilized in 77% of eligible patients. Patient demographics, comorbidities &amp; measures of acute severity of illness were similar pre- &amp; post-intervention. DSI-CB implementation was not associated with increases in primary adverse safety outcomes (Table 2). DSI-CB implementation was associated with significant reductions in rates of total respiratory cultures ordered, rates of positive respiratory cultures &amp; reductions in both total &amp; broad-spectrum ICU-AURs (Table 2, Figure 1). Conclusion Implementation of a novel VAP DSI-CB was safe, feasible &amp; associated with significant reductions in rates of respiratory culture positivity and ICU-AURs. This represents the first trial of a DSI targeting VAP &amp; a novel avenue for ICU antimicrobial stewardship. Large-scale trials are warranted. Disclosures Owen Albin, MD, Biomeriux: Grant/Research Support|Charles River Laboratories: Advisor/Consultant|Shionogi: Advisor/Consultant Weirauch J. Andrew, RRT, Drager Medical: Equipment loaned for research purposes, but no monetary funds were provided.|Jones and Bartlett Learning: Honoraria Krishna Rao, MD, MS, Merck &amp; Co.: Grant/Research Support|Rebiotix: Advisor/Consultant|Seres Therapeutics: Advisor/Consultant|Summit Therapeutics: Advisor/Consultant Keith S. Kaye, MD, MPH, Entasis: Advisor/Consultant|Entasis: Honoraria|GSK: Advisor/Consultant|GSK: Honoraria|Merck: Advisor/Consultant|Merck: Honoraria|Shionogi: Advisor/Consultant|Shionogi: Honoraria|VenatoRx: Advisor/Consultant|VenatoRx: Honoraria

Pseudomonas aeruginosa in children with cerebral palsy: a prospective study.

Children with cerebral palsy (CP) often present with chronic respiratory symptoms. Pseudomonas aeruginosa (PA), is a known pathogen associated with more severe respiratory disease. Preventive actions to eradicate this bacterium and to improve the respiratory condition of children with CP could be very valuable. Therefore, we assessed the prevalence of PA and its association with respiratory disease. Throat swabs were taken in children with CP, aged 0-18 years. Data from patient records were extracted from the electronic medical records. Follow-up of respiratory symptoms was done by the Liverpool respiratory symptom questionnaire (LRSQ) after 3 months. A throat swab and a completed LRSQ after 3 months were received from 79 children with CP. Twenty-eight patients (35.4%) were found to have at least one positive respiratory culture. Only 4 patients (5.1%) were contaminated with PA. Gram negative bacteria were isolated in 21.5% of the positive throat swabs, S. aureus was found in 13.9%. Most pathogens were found in patients with higher GMFCS score (GMFCS IV and V). Results of the LRSQ showed that 52.1% of these patients reported having 1 cold in the past 3 months. The prevalence of PA in our population of children with CP is low, gram-negative bacteria were most commonly found. The respiratory consequences of being colonized with these bacteria were limited. These results may have been affected by the COVID-19 pandemic. Further research is recommended.

Clinical and microbiological evaluation of ventilator-associated pneumonia in an intensive care unit in Vietnam

The increasing incidence of multidrug-resistant Gram-negative bacteria causing ventilator-associated pneumonia (VAP) is a global concern. A better understanding of the epidemiology of VAP in Southeast Asia is essential to optimise treatments and patient outcomes. VAP epidemiology in an intensive care unit in Vietnam was investigated. A prospective cohort study was conducted. Patients who were ventilated for >48 hours, diagnosed with VAP, and had a positive respiratory culture between October 2015 and March 2017 were included. Whole-genome sequencing (WGS) was performed on Acinetobacter baumannii isolates. We identified 125 patients (137 episodes) with VAP from 1,699 admissions. Twelve patients had 2 VAP episodes. The median age was 60 years (interquartile range: 48-70), and 68.8% of patients were male. Diabetes mellitus was the most frequent comorbidity (N=35, 28%). Acinetobacter baumannii was most frequently isolated in the first VAP episode (N=84, 67.2%) and was multiply resistant to meropenem, levofloxacin, and amikacin. The 30-day mortality rate was 55.2% (N=69) and higher in patients infected with A.baumannii (N=52, 65%). WGS results suggested a complex spread of multiple clones. In an intensive care unit in Vietnam, VAP due to A.baumannii had a high mortality rate, and A.baumannii and K.pneumoniae were multidrug resistant, with carbapenem resistance of 97% and 70%, respectively.

Impact of Respiratory Bacterial Codetection on Outcomes in Ventilated Infants With Bronchiolitis.

Viral bronchiolitis is a common cause of acute respiratory failure requiring intubation for infants. Bacterial respiratory tract infections can occur with bronchiolitis, although their prevalence and impact on outcomes are unclear, especially with increased use of noninvasive respiratory support. This was a single-center retrospective cohort study of children <2 years old requiring intubation in the emergency department for bronchiolitis from 2012 to 2017 who had viral testing plus a lower respiratory culture obtained. We evaluated the impact of bacterial codetection (positive respiratory culture plus moderate or many polymorphonuclear neutrophils on Gram stain) on mechanical ventilation (MV) duration and intensive care unit length of stay using multivariable gamma regression. Of 149 patients enrolled, 52% had bacterial codetection. In adjusted analysis, patients with codetection had shorter MV duration [adjusted relative risk (aRR) 0.819, 95% confidence interval (CI): 0.69-0.98; marginal mean duration of 5.31 days (4.71-5.99) compared to 6.48 days (5.72-7.35) without codetection]. Patients with codetection had a shorter intensive care unit stay [aRR 0.806 (0.69-0.94); marginal mean length of stay 6.9 days (6.21-7.68) vs. 8.57 days (7.68-9.56) without codetection]. The association between codetection and duration of ventilation appears confined to those receiving earlier antibiotics (less than the median time) rather than later antibiotics [aRR 0.738 (0.56-0.95) for earlier vs. aRR 0.92 (0.70-1.18) for later]. Respiratory bacterial codetection is common and associated with shorter MV duration in infants requiring early intubation for bronchiolitis. Early antibiotics may contribute to these outcomes, but further multicenter studies are needed to understand the role of codetection and antibiotics on bronchiolitis outcomes.

Risk Factors and Mortality of Elderly Patients with Hospital-Acquired Pneumonia of Carbapenem-Resistant Klebsiella pneumoniae Infection.

Hospital-acquired pneumonia (HAP) caused by carbapenem-resistant K. pneumoniae (CRKP), especially in elderly patients, results in high morbidity and mortality. Studies on risk factors, mortality, and antimicrobial susceptibility of CRKP pulmonary infection among elderly patients are lacking. A retrospective case-control study was conducted from January 2019 to December 2021. The elderly inpatients (≥65 years) who were diagnosed with HAP caused by K. pneumoniae were enrolled. Clinical data were collected. Univariate and multivariate logistic regression analyses were used to identify risk factors. Propensity score matching was used to minimize the effect of potential confounding variables. Kaplan-Meier analysis was used to compare survival. A total of 115 patients with CRKP infection and 78 patients with carbapenem-susceptible K. pneumoniae (CSKP) infection were recruited. There were four independent risk factors for CRKP infection: history of intensive care unit (ICU) stays from hospital admission to positive respiratory specimen culture for K. pneumoniae (odds ratio (OR)=2.530), Charlson comorbidity index score ≥3 (OR = 2.420), prior exposure to carbapenems (OR = 5.280), and prior K. pneumoniae infection or colonization in the preceding 3 years (OR = 18.529). The all-cause 30-day mortality was 22.3%, the mortality of CRKP and CSKP infection was 28.7% and 12.8%, respectively. Independent risk factors for mortality included: older age (OR = 1.107), immunocompromised patients (OR = 8.632), severe pneumonia (OR = 51.244), quick Sepsis-related Organ Failure Assessment (qSOFA) score ≥2 (OR = 6.187), exposure to tigecycline before infection (OR = 24.702), and prolonged ICU stay (OR = 0.987). Thirty-day mortality was significantly lower in patients receiving ceftazidime-avibactam (CAZ-AVI) containing regimens than patients receiving polymyxin B sulfate (PB) containing regimens (P = 0.048). qSOFA score had a good prognostic effect [area under receiver operating characteristic curve (AUROC) of 0.838]. Active screening of CRKP for the high-risk populations, especially elderly patients, is significant for early detection and successful management of CRKP infection.

Nontuberculous mycobacterial (NTM) infections in bronchiectasis patients: A retrospective US registry cohort study

RationaleLongitudinal epidemiological and clinical data are needed to improve the management of patients with bronchiectasis developing nontuberculous mycobacterial (NTM) pulmonary disease. ObjectivesTo describe the epidemiology, patient management, and treatment outcomes of NTM infections in patients with bronchiectasis enrolled in the United States Bronchiectasis and NTM Research Registry (US BRR). MethodsThis was a retrospective cohort study of patients with bronchiectasis and NTM infections enrolled with follow-up in the US BRR in 2008–2019. The study included patients with ≥1 positive NTM respiratory culture in the 24-month baseline period (baseline NTM cohort) and/or during the annual follow-up visits (incident NTM cohort). Incidence, prevalence, baseline patient characteristics, treatment exposure, treatment outcomes, and respiratory clinical outcomes were described in the baseline NTM cohort, incident NTM cohort, and both cohorts combined (prevalent NTM cohort). ResultsBetween 2008 and 2019, 37.9% (1457/3840) of patients with bronchiectasis in the US BRR met the inclusion criteria for this study and were reported to have Mycobacterium avium complex (MAC) and/or Mycobacterium abscessus complex (MABSC) infections. MAC prevalence increased steadily in the US BRR during 2009–2019; incidence was relatively stable, except for a peak in 2011 followed by a slow decrease. MABSC and mixed MAC/MABSC infections were rare. Most patients with bronchiectasis and NTM infections in the registry were female, White, and aged >65 years. The antibiotics administered most commonly reflected current guidelines. In the prevalent cohort, 44.9% of MAC infections and 37.1% of MABSC infections remained untreated during follow-up, and MAC treatment was initiated with delay (>90 days after positive NTM respiratory culture) twice as frequently as promptly (≤90 days after positive NTM respiratory culture) (68.6% vs 31.4%, respectively). The median time from diagnosis to treatment was shorter for MABSC versus MAC infections (194.0 days [interquartile range (IQR) 8.0, 380.0] vs 296.0 days [IQR 35.0, 705.0], respectively). Among patients with MAC infections who completed treatment, 27.6% were classified as cured and 29.6% as treatment failure during the annual follow-up visit window. For MABSC, these proportions were 25.0% and 28.0%, respectively. ConclusionsA considerable proportion of MAC and MABSC infections were untreated or treated after initial delay/observation. MABSC infections were more likely to be treated and start treatment sooner than MAC infections. Further longitudinal studies are warranted to evaluate the monitor-with-delay approach and inform clinical guidelines.

Using Methicillin-Resistant Staphylococcus aureus Nasal Screens to Rule Out Methicillin-Resistant S aureus Pneumonia in Surgical Intensive Care Units

IntroductionThe methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction (PCR) has a high negative predictive value (NPV). We aimed to understand if there was a difference in the NPV of the MRSA screen in surgical intensive care units (ICUs) and to determine its role in antibiotic de-escalation. MethodsWe performed a single-center, retrospective cohort study of adults with a positive respiratory culture and MRSA nasal PCR admitted to a surgical ICU from 2016 to 2019. Patients were stratified by surgical ICU: cardiothoracic/cardiovascular intensive care unit (CVICU) or transplant/acute care surgery intensive care unit (ACS-ICU). Our primary outcome was the NPV of MRSA screen. Secondary outcome was the duration of empiric MRSA-targeted therapy. ResultsWe analyzed 61 patients: 42.6% (n = 26) ACS-ICU and 57.4% (n = 35) CVICU. There were no differences in age, comorbidities, prior MRSA infection, recent antibiotic use, immunocompromised status, or renal replacement therapy. At pneumonia diagnosis, more patients in the ACS-ICU were hospitalized ≥5 d (65.4% versus 8.6%, P < 0.0001) and more patients in the CVICU were in septic shock (88.6% versus 34.5%, P < 0.0001) and thrombocytopenic (40% versus 11.5%, P = 0.02). NPV of the PCR was similar (ACS-ICU: 0.92 [0.75-0.98], CV-ICU 0.89 [0.73-0.96]). On multivariable linear regression, the CVICU was associated with longer empiric therapy (β 1.5, 95% CI 0.8-2.3, P < 0.0001), as was hospitalization for ≥5 d (β 0.73, 95% CI 0.06-1.39, P = 0.03). ConclusionsThe MRSA nasal PCR screen has a high NPV for ruling out MRSA pneumonia in critically ill surgical patients. However, patients in the CVICU and patients hospitalized ≥5 d had a longer time to de-escalation of MRSA-targeted therapy, potentially due to higher clinical risk profile.