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Microbial investigations in throat swab and tracheal aspirate specimens are beneficial to predict the corresponding endotracheal tube biofilm flora among intubated neonates with ventilator-associated pneumonia.

ABSTRACT: Ventilator-associated pneumonia (VAP) is a common nosocomial infection in neonatal intensive care units with high morbidity and mortality. Bacterial biofilm in the endotracheal tube (ET) provides a notable and persistent source of pathogens that may cause VAP, and thus is important for VAP detection. However, during intubation microbial investigations in ET, samples are unavailable due to the infeasibility of collecting ET samples during intubation of neonates. It is therefore of great importance to find alternative sources of samples that can help identify the ET biofilm flora. In the present study, the microbial signatures of throat swabs and tracheal aspirates were compared with ET biofilm samples from VAP neonates using 16S ribosomal RNA gene polymerase chain reaction, denaturing gradient gel electrophoresis (DGGE), cloning and sequencing. Sequences were assigned to phylogenetic species using BLAST. Microbial diversity and richness among the three types of specimens were compared based on their DGGE fingerprints, and taxonomic characteristics based on the BLAST results. The microbial richness and diversity of ET biofilms were similar to tracheal aspirate yet significantly different from throat swab samples (P<0.05). Compared with ET biofilms, the overall constituent ratio of microflora was significantly different in throat swab and tracheal aspirate samples (P<0.05). However tracheal aspirate samples were useful for predicting Staphylococcus sp. in ET biofilms with a sensitivity of 85.7% and a specificity of 83.3%. The sensitivity for the combination of tracheal aspirate and throat swab samples to detect Staphylococcus sp. in ET biofilms was 100%. The detection of Pseudomonas sp. in throat swabs assisted its identification in ET biofilms (sensitivity 33.3% and specificity 100%). The results of the present study suggest that microbial investigations in throat swab and tracheal aspirate samples are beneficial for identifying the ET biofilm flora. There may therefore be clinical applications of using substituent samples to identify pathogens in ET biofilms for VAP surveillance among intubated neonates.

SUBMITTER: Pan Y

PROVIDER: S-EPMC5526163 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature

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Microbial investigations in throat swab and tracheal aspirate specimens are beneficial to predict the corresponding endotracheal tube biofilm flora among intubated neonates with ventilator-associated pneumonia.

Pan Yun Y Du Lizhong L Ai Qing Q Song Sijie S Tang Xiaoli X Zhu Danping D Yu Jialin J

Experimental and therapeutic medicine 20170620 2

Ventilator-associated pneumonia (VAP) is a common nosocomial infection in neonatal intensive care units with high morbidity and mortality. Bacterial biofilm in the endotracheal tube (ET) provides a notable and persistent source of pathogens that may cause VAP, and thus is important for VAP detection. However, during intubation microbial investigations in ET, samples are unavailable due to the infeasibility of collecting ET samples during intubation of neonates. It is therefore of great importanc ...[more]

PMID: 28810610

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Project description:BackgroundMicroaspiration of gastric and oropharyngeal secretions is the main causative mechanism of ventilator-associated pneumonia (VAP). Transesophageal echocardiography (TEE) is a routine investigation tool in intensive care unit and could enhance microaspiration. This study aimed at evaluating the impact of TEE on microaspiration and VAP in intubated critically ill adult patients.MethodsIt is a four-center prospective observational study. Microaspiration biomarkers (pepsin and salivary amylase) concentrations were quantitatively measured on tracheal aspirates drawn before and after TEE. The primary endpoint was the percentage of patients with TEE-associated microaspiration, defined as: (1) ≥ 50% increase in biomarker concentration between pre-TEE and post-TEE samples, and (2) a significant post-TEE biomarker concentration (> 200 μg/L for pepsin and/or > 1685 IU/L for salivary amylase). Secondary endpoints included the development of VAP within three days after TEE and the evolution of tracheal cuff pressure throughout TEE.ResultsWe enrolled 100 patients (35 females), with a median age of 64 (53-72) years. Of the 74 patients analyzed for biomarkers, 17 (23%) got TEE-associated microaspiration. However, overall, pepsin and salivary amylase levels were not significantly different between before and after TEE, with wide interindividual variability. VAP occurred in 19 patients (19%) within 3 days following TEE. VAP patients had a larger tracheal tube size and endured more attempts of TEE probe introduction than their counterparts but showed similar aspiration biomarker concentrations. TEE induced an increase in tracheal cuff pressure, especially during insertion and removal of the probe.ConclusionsWe could not find any association between TEE-associated microaspiration and the development of VAP during the three days following TEE in intubated critically ill patients. However, our study cannot formally rule out a role for TEE because of the high rate of VAP observed after TEE and the limitations of our methods.

Project description:BackgroundVentilator-associated pneumonia (VAP) is a well-known, life-threatening disease that persists despite preventative measures and approved antibiotic therapies. This prospective observational study investigated bacterial airway colonization, and whether its detection and quantification in the endotracheal aspirate (ETA) is useful for identifying mechanically ventilated ICU patients who are at risk of developing VAP.Methods240 patients admitted to 3 ICUs at the Lahey Hospital and Medical Center (Burlington, MA) between June 2014 and June 2015 and mechanically ventilated for > 2 days were included. ETA samples and clinical data were collected. Airway colonization was assessed, and subsequently categorized into "heavy" and "light" by semi-quantitative microbiological analysis of ETAs. VAP was diagnosed retrospectively by the study sponsor according to a pre-specified pneumonia definition.ResultsPathogenic bacteria were isolated from ETAs of 125 patients. The most common species isolated was S. aureus (56.8%), followed by K. pneumoniae, P. aeruginosa, and E. coli (35.2% combined). VAP was diagnosed in 85 patients, 44 (51.7%) with no bacterial pathogen, 18 associated with S. aureus and 18 Gram-negative-only cases, and 5 associated with other Gram-positive or mixed species. A higher proportion of patients who were heavily colonized with S. aureus developed VAP (32.4%) associated with S. aureus compared to those lightly colonized (17.6%). The same tendency was seen for patients heavily and lightly colonized with Gram-negative pathogens (30.0 and 0.0%, respectively). Detection of S. aureus in the ETA preceded S. aureus VAP by approximately 4 days, while Gram-negative organisms were first detected 2.5 days prior to Gram-negative VAP. VAP was associated with significantly longer duration of mechanical ventilation and hospitalization regardless of microbiologic cause when compared to patients who did not develop VAP.ConclusionsThe overall VAP rate was 35%. Heavy tracheal colonization supported identification of patients at higher risk of developing a corresponding S. aureus or Gram-negative VAP. Detection of bacterial ETA-positivity tended to precede VAP.

Project description:BackgroundNo univocal recommendation exists for microbiological diagnosis of ventilator-associated pneumonia (VAP). Sampling of either proximal or distal respiratory tract likely impacts on the broad range of VAP incidence between cohorts. Immune biomarkers to rule-in/rule-out VAP diagnosis, although promising, have not yet been validated. COVID-19-induced ARDS made VAP recognition even more challenging, often leading to overdiagnosis and overtreatment. We evaluated the impact of different respiratory samples and laboratory techniques on VAP incidence and microbiological findings in COVID-19 patients.MethodsProspective single-centre cohort study conducted among COVID-19 mechanically ventilated patients in Policlinico Hospital (Milan, Italy) from January 2021 to May 2022. Microbiological confirmation of suspected VAP (sVAP) was based on concomitant endotracheal aspirates (ETA) and bronchoalveolar lavage (BAL). Conventional and fast microbiology (FILMARRAY® Pneumonia Panel plus, BALFAPPP) as well as immunological markers (immune cells and inflammatory cytokines) was analysed.ResultsSeventy-nine patients were included. Exposure to antibiotics and steroid therapy before ICU admission occurred in 51/79 (64.6%) and 60/79 (65.9%) patients, respectively. Median duration of MV at VAP suspicion was 6 (5-9) days. Incidence rate of microbiologically confirmed VAP was 33.1 (95% CI 22.1-44.0) and 20.1 (95% CI 12.5-27.7) according to ETA and BAL, respectively. Concordance between ETA and BAL was observed in 35/49 (71.4%) cases, concordance between BALFAPPP and BAL in 39/49 (79.6%) cases. With BAL as reference standard, ETA showed 88.9% (95% CI 70.8-97.7) sensitivity and 50.0% (95% CI 28.2-71.8) specificity (Cohen's Kappa 0.40, 95% CI 0.16-0.65). BALFAPPP showed 95.0% (95% CI 75.1-99.9) sensitivity and 69% (95% CI 49.2-84.7) specificity (Cohen's Kappa 0.60, 95% CI 0.39-0.81). BAL IL-1β differed significantly between VAP (135 (IQR 11-450) pg/ml) and no-VAP (10 (IQR 2.9-105) pg/ml) patients (P = 0.03).ConclusionsIn COVID-19 ICU patients, differences in microbial sampling at VAP suspicion could lead to high variability in VAP incidence and microbiological findings. Concordance between ETA and BAL was mainly limited by over 20% of ETA positive and BAL negative samples, while BALFAPPP showed high sensitivity but limited specificity when evaluating in-panel targets only. These factors should be considered when comparing results of cohorts with different sampling. BAL IL-1β showed potential in discriminating microbiologically confirmed VAP.Clinical trial registrationNCT04766983, registered on February 23, 2021.

Dataset Information

Microbial investigations in throat swab and tracheal aspirate specimens are beneficial to predict the corresponding endotracheal tube biofilm flora among intubated neonates with ventilator-associated pneumonia.

Publications

Microbial investigations in throat swab and tracheal aspirate specimens are beneficial to predict the corresponding endotracheal tube biofilm flora among intubated neonates with ventilator-associated pneumonia.

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