Challenging the "Culture" of the Tracheal Aspirate

Variations and National Perspectives on Evaluation and Management of Ventilator-Associated Pneumonia in Neonatal Intensive Care Units: An In-Depth Survey Analysis

Introduction Infants in the neonatal intensive care unit (NICU) are vulnerable to ventilator-associated pneumonia (VAP), which increases their morbidity and mortality. There is a significant overlap of clinical features of neonatal VAP with other pulmonary pathologies, particularly in preterm infants, which can make the definitive diagnosis and management of VAP challenging. Objective Our study surveyed NICU providers across the United States to understand the perspectives and variations in neonatal VAP diagnostic and management practices. Methods The REDCap survey was distributed to the actively practicing members of the Section on Neonatal-Perinatal Medicine (SoNPM) of the American Academy of Pediatrics (AAP). We used descriptive statistics to analyze the data from the respondents. Results Of 254 respondents, the majority (86.6%, 220) were neonatologists and had a relatively even geographical distribution. Most (75.9%, 193) stated that they would perform a gram stain and respiratory culture as part of a sepsis workup irrespective of the patient's duration on invasive mechanical ventilation (IMV); 224 (88.2%) of providers preferred the endotracheal aspiration (ETA) technique to collect specimens. In cases where a positive respiratory culture was present, VAP (52.4%, 133) was the predominantly assigned diagnosis, followed by pneumonia (27.2%, 69) and ventilator-associated tracheitis (VAT) (9.8%, 25). Respondents reported a prescription of intravenous gentamicin (70%, 178) and vancomycin (41%, 105) as the initial empiric antibiotic drugs, pending final respiratory culture results. Most respondents (55.5%, 141) opted for seven days of antibiotics duration to treat VAP. The reported intra-departmental variation among colleagues in acquiring respiratory cultures and prescribing antibiotics for VAP was 48.8% (124) and 37.4% (95), respectively, with slightly more than half (53.5%, 136) of providers reporting having VAP prevention guidelines in their units. Conclusion The survey study revealed inconsistencies in the investigation, diagnostic nomenclature, choice of antibiotic, and treatment duration for neonatal VAP. Consequently, there is a pressing need for further research to establish a clear definition and evidence-based criteria for VAP.

Prophylactic fluconazole protocol in very low birth weight infants: invasive candidiasis prevention in a Latin American neonatal intensive care unit

OBJECTIVE

To evaluate the effect of prophylactic fluconazole for very low birth weight infants (VLBWI) in a neonatal intensive care unit (NICU) with a 7.8% incidence of invasive candidiasis (IC).

STUDY DESIGN

Interventional pre-post cohort study comparing 2 years with and without fluconazole prophylaxis protocol (2016-2018 = 228 infants and 2019-2021 = 125 infants). Fluconazole was administered to all extremely low birth weight infants (ELBWI) and infants with BW 1001-1500 g with risk factors or positive carrier cultures. Liver function tests were performed weekly.

RESULTS

The incidence of IC decreased from 7.8% to 2.4% (OR:0.3, p = 0.05) with the use of prophylactic fluconazole for VLBWI and in ELBWI decreased from 16,7% to 3,7% (OR:0.1, p = 0.04). No significant differences were seen in mortality.

CONCLUSIONS

Fluconazole is a safe, effective, and feasible strategy to prevent IC in a Latin American country.

Endotracheal Aspirate and Ventilator-Associated Pneumonia in Neonates: Revisiting an Age-Old Debate

OBJECTIVES

To explore the utility of endotracheal aspirates (ETA) for analyzing microbiological yield, incidence, risk factors for VAP, and clinically relevant outcomes.

METHODS

Ventilated neonates suspected to have VAP were studied prospectively; they were classified as "VAP" or "No VAP" based on a predefined combination of clinical, radiological, and laboratory criteria. The microbiological yield from blood and ETA cultures was analyzed.

RESULTS

Of 165 neonates who were ventilated for > 48 h, 65 were suspected of having VAP. Thirty-six (22.9%) were classified as VAP. Microbiological agents could be identified in 31 cases (86.1%) by ETA/blood cultures. Acinetobacter sp was the common organism identified. Duration of ventilation, and a higher number of reintubations before suspicion of VAP were significant risk factors for VAP. Positive ETA culture was associated with a greater duration of oxygen therapy and ventilation days after suspicion of VAP.

CONCLUSIONS

The commonest culture yield from ETA in those suspected to have VAP was gram-negative bacilli. Duration of ventilation and reintubations were identified as significant risk factors for VAP. These are potentially modifiable factors. Positive ETA culture was associated with longer needs for respiratory supports. Negative ETA culture might encourage clinicians to stop antibiotics.

TRIAL REGISTRATION

Clinical Trials Registry of India No. CTRI/2019/03/017912,  www.ctri.nic.in.

Impact of Organism Reporting from Endotracheal Aspirate Cultures on Antimicrobial Prescribing Practices in Mechanically Ventilated Pediatric Patients

Endotracheal aspirate cultures (EACs) help diagnose lower respiratory tract infections in mechanically ventilated patients but are limited by contamination with normal microbiota and variation in laboratory reporting. Increased use of EACs is associated with increased antimicrobial prescribing, but the impact of microbiology reporting on prescribing practices is unclear. This study was a retrospective analysis of EACs from mechanically ventilated patients at Children's Hospital Colorado (CHCO) admitted between 1 January 2019 and 31 December 2019. Chart review was performed to collect all culture and Gram stain components, as well as antibiotic use directed to organisms in culture. Reporting concordance was determined for each organism using American Society for Microbiology guidelines. Days of therapy were calculated for overreported and guideline-concordant organisms. A multivariable model was used to assess the relationship between organism reporting and total days of therapy. Overall, 448 patients with 827 EACs were included in this study. Among patients with tracheostomy, 25 (8%) organisms reported from EACs were overreported and contributed 48 days of excess therapy, while 227 (29%) organisms from the EACs of endotracheally intubated patients were overreported, contributing 472 excess days of therapy. After adjustment, organism overreporting was associated with a >2-fold-higher rate of antimicrobial therapy than guideline-concordant reporting (incident rate ratio [IRR], 2.83; 95% confidence interval [CI], 1.23, 6.53; P < 0.05). Overreported organisms from respiratory cultures contribute to excess antimicrobial therapy exposure in mechanically ventilated patients. Microbiology laboratories have an opportunity to mitigate antimicrobial overuse through standardized reporting practices.

Improving management of ventilator associated tracheitis in a level IV NICU

BACKGROUND

There are no published guidelines regarding the diagnosis and treatment of ventilator-associated tracheitis (VAT) in the neonatal intensive care unit (NICU). VAT is likely over-diagnosed and over-treated, increasing antibiotic burden and cost.

LOCAL PROBLEM

Diagnosis and treatment of VAT were entirely NICU provider dependent.

METHODS

Retrospective pre- and post-intervention chart reviews were performed.

INTERVENTIONS

A VAT diagnosis and treatment algorithm was created for use in the care of intubated patients without tracheostomies. 3 plan-do-study-act (PDSA) cycles were used to implement change.

RESULTS

Intubated patients treated for VAT with <25 PMNs on Gram stain decreased from 79% to 35% following the quality improvement (QI) initiative. Treatment of VAT with >7 days of antibiotic therapy decreased from 42% to 10%.

CONCLUSION

Implementing a QI initiative to improve the diagnosis and treatment of VAT in the NICU decreased the percent of patients treated inappropriately for VAT.

Multi-drug resistant gram-negative bacterial pneumonia: etiology, risk factors, and drug resistance patterns

Bacterial pneumonia is one of the most serious public health issues owing to its medical and economic costs, which result in increased morbidity and mortality in people of all ages around the world. Furthermore, antimicrobial resistance has risen over time, and the advent of multi-drug resistance in GNB complicates therapy and has a detrimental impact on patient outcomes. The current review aimed to summarize bacterial pneumonia with an emphasis on gram-negative etiology, pathogenesis, risk factors, resistance mechanisms, treatment updates, and vaccine concerns to tackle the problem before it causes a serious consequence. In conclusion, the global prevalence of GNB in CAP was reported 49.7% to 83.1%, whereas in VAP patients ranged between 76.13% to 95.3%. The most commonly reported MDR-GNB causes of pneumonia were A. baumannii, K. pneumoniae, and P. aeruginosa, with A. baumannii isolated particularly in VAP patients and the elderly. In most studies, ampicillin, tetracyclines, amoxicillin-clavulanic acid, cephalosporins, and carbapenems were shown to be highly resistant. Prior MDR-GNB infection, older age, previous use of broad-spectrum antibiotics, high frequency of local antibiotic resistance, prolonged hospital stays, ICU admission, mechanical ventilation, and immunosuppression are associated with the MDR-GNB colonization. S. maltophilia was reported as a severe cause of HAP/VAP in patients with mechanically ventilated and having hematologic malignancy due to its ability of biofilm formation, site adhesion in respiratory devices, and its intrinsic and acquired drug resistance mechanisms. Effective combination therapies targeting PDR strains and drug-resistant genes, antibiofilm agents, gene-based vaccinations, and pathogen-specific lymphocytes should be developed in the future.

Practice Summary of Antimicrobial Therapy for Commonly Encountered Conditions in the Neonatal Intensive Care Unit: A Canadian Perspective

Neonates are highly susceptible to infections owing to their immature cellular and humoral immune functions, as well the need for invasive devices. There is a wide practice variation in the choice and duration of antimicrobial treatment, even for relatively common conditions in the NICU, attributed to the lack of evidence-based guidelines. Early decisive treatment with broad-spectrum antimicrobials is the preferred clinical choice for treating sick infants with possible bacterial infection. Prolonged antimicrobial exposure among infants without clear indications has been associated with adverse neonatal outcomes and increased drug resistance. Herein, we review and summarize the best practices from the existing literature regarding antimicrobial use in commonly encountered conditions in neonates.

Association of Endotracheal Aspirate Culture Variability and Antibiotic Use in Mechanically Ventilated Pediatric Patients

IMPORTANCE

Endotracheal aspirate cultures are commonly collected from patients with mechanical ventilation to evaluate for ventilator-associated pneumonia or tracheitis. However, the respiratory tract is not sterile, making differentiating between colonization from bacterial infection challenging, and results may be unreliable owing to variable specimen quality and sample processing across laboratories. Despite these limitations, clinicians routinely interpret bacterial growth in endotracheal aspirate cultures as evidence of infection, sometimes regardless of organism significance, prompting antibiotic treatment.

OBJECTIVE

To assess the variability in endotracheal aspirate culture rates and the association between culture rates and antibiotic prescribing among patients with mechanical ventilation across children's hospitals in the US.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional retrospective analysis of data obtained from the Children's Hospital Association Pediatric Health Information System database between January 1, 2016, through December 31, 2019. Participants were all patients hospitalized with mechanical ventilation aged less than 18 years.

EXPOSURES

A charge for an endotracheal aspirate culture on a ventilated day.

MAIN OUTCOMES AND MEASURES

Endotracheal aspirate culture rate and antibiotic days of therapy per ventilated days. For mechanical ventilation, clinical transaction classification codes for mechanical ventilation other unspecified ventilator assistance were used. To identify respiratory cultures, the laboratory test code for aerobic culture was used and relevant keywords (ie, respiratory tract, sputum) were used to identify sources in the hospital charge description master.

RESULTS

A total of 152 132 patients were identified among 31 hospitals. Among these patients, 79 691 endotracheal aspirate cultures were collected on a ventilator-day (patients aged less than 1 year, 44%; 1-4 years, 27%, 5-11 years. 16%, and 12-18 years, 13%; 3% were Asian; 17% Hispanic; 21% non-Hispanic Black; 45% Non-Hispanic White patients; 14% were other; 56% of patients were male, 44% were female). The overall median rate of culture use was 46 per 1000 ventilator-days (IQR, 32-73 cultures per 1000 ventilator-days). The endotracheal aspirate culture rate was positively correlated with the hospital's antibiotic days of therapy rate (R = 0.46; P = .009). In a multivariable model adjusting for patient-level and hospital-level characteristics and among patients with mechanical ventilation, each additional endotracheal aspirate culture was associated with 2.87 (95% CI, 2.74-3.01) higher odds of receiving additional days of therapy compared with patients who did not receive and endotracheal aspirate culture.

CONCLUSIONS AND RELEVANCE

In this study, notable variability was found in endotracheal aspirate culture rates across US pediatric hospitals and pediatric intensive care units, and endotracheal aspirate culture use was associated with increased antibiotic use. These findings suggest an opportunity for diagnostic and antibiotic stewardship to standardize testing and treatment of suspected ventilator-associated infections in pediatric patients with mechanical ventilation pediatric patients.

Care of children with home mechanical ventilation in the healthcare continuum

Introduction:The care of children with invasive home mechanical ventilation (HMV) is challenging and insufficiently described in the literature. Objectives:Our objective regarding this unique and growing population is to describe our institution's pediatric chronic HMV program and discuss our current understanding of best care practices. Methods: In addition to characterizing the clinical landscape of our program, we describe demographics for our roughly 223 current HMV patients with comparisons to available national data.  We discuss evidence and expert opinion regarding various elements of care including initiation of HMV, caregiver education, equipment concerns, inpatient care, and longitudinal care.Results: Data was collected but not statistically analyzed for our roughly 223 current patients and historical cohort. Descriptive data included demographic information, patient medical characteristics and complexity, and reasons for rehospitalizations.Conclusions:While we have provided institutional expertise regarding the care of this complex population, the evidence base remains insufficient and there are many areas which need future research to develop standardized care practice guidelines for children with HMV.

Lack of utility of tracheal aspirates in the management of suspected pneumonia in intubated neonates

OBJECTIVES

To evaluate the utility of tracheal aspirates in suspected pneumonia in intubated neonates and to measure the burden of antibiotic use associated with a positive tracheal aspirate culture.

DESIGN

Retrospective cohort study between January 2016 and December 2017.

SETTING

A level IV neonatal intensive care unit (NICU).

PATIENTS

Intubated patients with a tracheal aspirate culture.

METHODS

Data on temporally associated clinical measures of illness, laboratory and radiographic testing, and clinical demographic information were analyzed.

RESULTS

Positive tracheal aspirate cultures were associated with lower birth weight and a normal immature to total neutrophil ratio (I/T ratio). Positive tracheal aspirates were not significantly associated with clinical, laboratory, or radiographic markers used in clinical practice to screen for infection. Despite the lack of positive clinical associations, a positive tracheal aspirate culture was associated with increased risk of prolonged antibiotic exposure.

CONCLUSION

These findings suggest that positive tracheal aspirates do not always represent clinical infection and may result in unnecessary antibiotic exposure.

Elevated neutrophil-lymphocyte ratios in extremely preterm neonates with histologic chorioamnionitis

OBJECTIVE

Histologic chorioamnionitis (HCA) is a placental inflammation linked to preterm birth and adverse neonatal outcome. The neutrophil-lymphocyte ratio (NLR) can identify various inflammatory disorders, however its utility in HCA is not clear. Our goal was to examine NLR values and HCA diagnoses in at-risk pregnancies and neonates.

STUDY DESIGN

We retrospectively analyzed the EHR of mothers and preterm (<33 wk GA) neonates with or without HCA (identified by placental histology). The NLR was calculated from complete blood counts in laboring women and in their neonates (0-24 h of life).

RESULT

In 712 consecutive gestations, 50.8% had HCA (26.5% fetal HCA). The neonatal NLR (0-12 h, 13-24 h) predicted fetal HCA better than chance alone (p = 0.01 and 0.002, respectively).

CONCLUSION

Early NLR elevation in preterm neonates is consistent with a diagnosis of fetal HCA. The NLR may identify preterm neonates at risk for HCA-related complications.

The Pediatric Endotracheal Aspirate Culture Survey (PETACS): Examining Practice Variation across Pediatric Microbiology Laboratories in the United States

In the absence of evidence-based laboratory guidelines, the workup and interpretation of tracheal aspirate (TA) cultures remains controversial and confusing within the fields of clinical microbiology, infectious diseases, and critical care. Between 22 January and 24 February 2020, we conducted a national, web-based survey of microbiology laboratory personnel in free-standing pediatric hospitals and adult hospitals containing pediatric facilities regarding the laboratory practices used for TA specimens. We hypothesized there would be substantial center-level variability in laboratory processing of TA cultures. The response rate for the survey was 48% (73/153). There was a high level of variability in the criteria used for all processes, including specimen receipt, Gram staining, and culture reporting. Most respondents (77%) reported they do not reject TA specimens based on Gram stain criteria, and 44% of labs do not require that a minimum number of Gram stain fields be reviewed prior to reporting results. Overall, nonacademic hospital laboratories and pediatric-only laboratories are more likely to identify, report, and perform susceptibility testing on organisms from TA cultures, regardless of organism quantity or predominance. There is a substantial amount of process variability among pediatric microbiology laboratories that affects TA culture reporting, and which guides treatment decisions. This variation within and among labs makes clinical outcome studies related to TA cultures difficult to interpret. This study serves as a pragmatic step in informing the development of robust clinical guidelines. Clinical outcome and implementation studies are necessary to determine the effectiveness of guidelines for TA cultures.

Predictors of antibiotic utilization among intensive care unit patients

Increased antibiotic utilization in hospital is linked to higher total treatment costs, together with increased length of stay, surgery and emergency admission. The aim of our retrospective cohort study was to investigate predictors of antibiotic utilization per single patient from an intensive care unit (ICU) of a tertiary care, university hospital in Serbia. Average utilization of antibiotics per patient was 23.9 ± 20.4 defined daily doses (DDDs). Diagnosis of systemic infection increased antibiotics utilization per patient for 10.0 DDDs, positive blood culture for 5.4 DDDs, isolation of Pseudomonas spp. for 19.5 DDDs, isolation of Acinetobacter spp. for 6.3 DDDs and injury for 7.3 DDDs per patient. Each new day of hospitalization and each additional drug prescribed increased utilization for further 0.3 DDDs and 1.2 DDDs, respectively. Appropriate and limited use of antibiotics in ICU is of key importance for preserving their effectiveness and decrease of bacterial resistance.