Update of the treatment of nosocomial pneumonia in the ICU.

In accordance with the recommendations of, amongst others, the Surviving Sepsis Campaign and the recently published European treatment guidelines for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), in the event of a patient with such infections, empirical antibiotic treatment must be appropriate and administered as early as possible. The aim of this manuscript is to update treatment protocols by reviewing recently published studies on the treatment of nosocomial pneumonia in the critically ill patients that require invasive respiratory support and patients with HAP from hospital wards that require invasive mechanical ventilation. An interdisciplinary group of experts, comprising specialists in anaesthesia and resuscitation and in intensive care medicine, updated the epidemiology and antimicrobial resistance and established clinical management priorities based on patients' risk factors. Implementation of rapid diagnostic microbiological techniques available and the new antibiotics recently added to the therapeutic arsenal has been reviewed and updated. After analysis of the categories outlined, some recommendations were suggested, and an algorithm to update empirical and targeted treatment in critically ill patients has also been designed. These aspects are key to improve VAP outcomes because of the severity of patients and possible acquisition of multidrug-resistant organisms (MDROs).

Performance and impact of a multiplex PCR in ICU patients with ventilator-associated pneumonia or ventilated hospital-acquired pneumonia.

BACKGROUND: Early appropriate antibiotic therapy reduces morbidity and mortality of severe pneumonia. However, the emergence of bacterial resistance requires the earliest use of antibiotics with the narrowest possible spectrum. The Unyvero Hospitalized Pneumonia (HPN, Curetis) test is a multiplex PCR (M-PCR) system detecting 21 bacteria and 19 resistance genes on respiratory samples within 5 h. We assessed the performance and the potential impact of the M-PCR on the antibiotic therapy of ICU patients. METHODS: In this prospective study, we performed a M-PCR on bronchoalveolar lavage (BAL) or plugged telescoping catheter (PTC) samples of patients with ventilated HAP or VAP with Gram-negative bacilli or clustered Gram-positive cocci. This study was conducted in 3 ICUs in a French academic hospital: the medical and infectious diseases ICU, the surgical ICU, and the cardio-surgical ICU. A multidisciplinary expert panel simulated the antibiotic changes they would have made if the M-PCR results had been available. RESULTS: We analyzed 95 clinical samples of ventilated HAP or VAP (72 BAL and 23 PTC) from 85 patients (62 males, median age 64 years). The median turnaround time of the M-PCR was 4.6 h (IQR 4.4-5). A total of 90/112 bacteria were detected by the M-PCR system with a global sensitivity of 80% (95% CI, 73-88%) and specificity of 99% (95% CI 99-100). The sensitivity was better for Gram-negative bacteria (90%) than for Gram-positive cocci (62%) (p = 0.005). Moreover, 5/8 extended-spectrum beta-lactamases (CTX-M gene) and 4/4 carbapenemases genes (3 NDM, one oxa-48) were detected. The M-PCR could have led to the earlier initiation of an effective antibiotic in 20/95 patients (21%) and to early de-escalation in 37 patients (39%) but could also have led to one (1%) inadequate antimicrobial therapy. Among 17 empiric antibiotic treatments with carbapenems, 10 could have been de-escalated in the following hours according to the M-PCR results. The M-PCR also led to 2 unexpected diagnosis of severe legionellosis confirmed by culture methods. CONCLUSIONS: Our results suggest that the use of a M-PCR system for respiratory samples of patients with VAP and ventilated HAP could improve empirical antimicrobial therapy and reduce the use of broad-spectrum antibiotics.

Clinical impact of lung ultrasound monitoring for diagnosis of ventilator associated pneumonia: A diagnostic randomized controlled trial.

PURPOSE: Studies have shown that lung-ultrasound may be superior to chest x-ray (CXR) in diagnosing ventilator-associated pneumonia (VAP). This study investigated whether the use of lung-ultrasound monitoring could detect VAP earlier and improve patient outcome. METHODS: This was a single-center diagnostic randomized controlled trial. In the control group, VAP was diagnosed using a combination of CXR and clinical findings. In the intervention group, VAP was diagnosed using a combination of lung-ultrasound and clinical findings. The primary outcome measured was ventilator free days (VFD). Secondary outcomes were ICU mortality, length of stay in ICU, change in Sequential Organ Failure Score at day 4 compared to day 0 (delta SOFA), antibiotic duration and ventilator days. RESULTS: We randomized intubated patients until 44 VAP diagnosis was made in each group. VFD was higher in the intervention group than in the control group (7.80+/- 9.7 days versus 3.7+/- 6.4 days, p = .044). There were no differences between the groups in terms of ICU mortality (p=.104), ICU length of stay, (p = .058), ventilator days, (p = .081), delta SOFA (p = .10) and antibiotic duration (p = .70). CONCLUSION: The use of lung-ultrasound monitoring for diagnosis of VAP improves patient outcome when compared to the standard diagnostic strategy that relies on CXR.

Nurses' knowledge, experience and self-reported adherence to evidence-based guidelines for prevention of ventilator-associated events: A national online survey.

OBJECTIVE: To explore Australian intensive care nurses' knowledge of ventilator-associated pneumonia and self-reported adherence to evidence-based guidelines for the prevention of ventilator-associated events. DESIGN: A quantitative cross-sectional online survey was used. SETTING: The study was conducted in two Australia intensive care units, in large health services in Victoria and an Australia-wide nurses' professional association (Australian College of Critical Care Nurses). MAIN OUTCOME MEASURES: Participants' knowledge and self-reported adherence to evidence-based guidelines. RESULTS: The median knowledge score was 6/10 (IQR: 5-7). There was a significant positive association between completion of post graduate qualification and their overall knowledge score p = 0.014). However, there was no association (p = 0.674) between participants' years of experience in intensive care nursing and their overall score. The median self-reported adherence was 8/10 (IQR: 6-8). The most adhered to procedures were performing oral care on mechanically ventilated patients (n = 259, 90.9%) and semi-fowlers positioning of the patient (n = 241, 84.6%). There was no relationship between participants' knowledge and adherence to evidence-based guidelines (p = 0.144). CONCLUSION: Participants lack knowledge of evidence-based guidelines for the prevention of ventilator-associated pneumonia. Specific education on ventilator-associated events may improve awareness and guideline adherence.

Diagnosis of ventilator-associated pneumonia using electronic nose sensor array signals: solutions to improve the application of machine learning in respiratory research.

BACKGROUND: Ventilator-associated pneumonia (VAP) is a significant cause of mortality in the intensive care unit. Early diagnosis of VAP is important to provide appropriate treatment and reduce mortality. Developing a noninvasive and highly accurate diagnostic method is important. The invention of electronic sensors has been applied to analyze the volatile organic compounds in breath to detect VAP using a machine learning technique. However, the process of building an algorithm is usually unclear and prevents physicians from applying the artificial intelligence technique in clinical practice. Clear processes of model building and assessing accuracy are warranted. The objective of this study was to develop a breath test for VAP with a standardized protocol for a machine learning technique. METHODS: We conducted a case-control study. This study enrolled subjects in an intensive care unit of a hospital in southern Taiwan from February 2017 to June 2019. We recruited patients with VAP as the case group and ventilated patients without pneumonia as the control group. We collected exhaled breath and analyzed the electric resistance changes of 32 sensor arrays of an electronic nose. We split the data into a set for training algorithms and a set for testing. We applied eight machine learning algorithms to build prediction models, improving model performance and providing an estimated diagnostic accuracy. RESULTS: A total of 33 cases and 26 controls were used in the final analysis. Using eight machine learning algorithms, the mean accuracy in the testing set was 0.81 ± 0.04, the sensitivity was 0.79 ± 0.08, the specificity was 0.83 ± 0.00, the positive predictive value was 0.85 ± 0.02, the negative predictive value was 0.77 ± 0.06, and the area under the receiver operator characteristic curves was 0.85 ± 0.04. The mean kappa value in the testing set was 0.62 ± 0.08, which suggested good agreement. CONCLUSIONS: There was good accuracy in detecting VAP by sensor array and machine learning techniques. Artificial intelligence has the potential to assist the physician in making a clinical diagnosis. Clear protocols for data processing and the modeling procedure needed to increase generalizability.

Emergency nurses' knowledge about ventilator-associated pneumonia.

INTRODUCTION: Given the increasing number of patients requiring mechanical ventilation in emergency departments in recent years, prevention of ventilator-associated pneumonia is very important. Nurses play a significant role in prevention of ventilator-associated pneumonia. This study aimed to determine the emergency nurses knowledge about prevention of ventilator-associated pneumonia. METHODS: The present descriptive study was conducted in Iran, from July to October 2018. All the nurses with at least a bachelor degree, who are working in two emergency departments of two teaching hospitals, were asked to participate in this study. The "knowledge about ventilator-associated pneumonia" questionnaire consisting of 9 items was used to assess the knowledge of nurses. The results were analyzed using SPSS-16. RESULTS: In total, 53 nurses participated in this study. The mean score of correct answers of nurses to these 9 items was 4.4 ±â€¯1.6. Nurses give the most correct answer to the item about patient's position on the bed so as to reduce the risk of pneumonia with a correct answer of 72.9%. The least correct answer was also given to the item about how humidifier was changed with a correct answer of 1.9%. None of the nurses participating in the study were able to answer all the items correctly. The mean score of knowledge of nurses who had participated in workshops about taking care of patients on mechanical ventilation was significantly higher than those who had not participated in such workshops (4.8 vs. 3.8) (p = 0.045). The mean score of knowledge in nurses who were familiar with the international guidelines for ventilator-associated pneumonia prevention was significantly higher than those who were not familiar with such guidelines (5.1 vs. 4.1) (p = 0.045). CONCLUSION: Emergency nurses participated in this study had inadequate knowledge about the prevention of ventilator-associated pneumonia. Nurse's knowledge affected by participation in related workshop and familiarity with ventilator-associated pneumonia guidelines. Considering the importance of this issue, it is necessary to improve the knowledge of the emergency nurses in this matter by holding training courses.

Mechanical ventilation in patients with acute ischaemic stroke: from pathophysiology to clinical practice.

Most patients with ischaemic stroke are managed on the ward or in specialty stroke units, but a significant number requires higher-acuity care and, consequently, admission to the intensive care unit. Mechanical ventilation is frequently performed in these patients due to swallowing dysfunction and airway or respiratory system compromise. Experimental studies have focused on stroke-induced immunosuppression and brain-lung crosstalk, leading to increased pulmonary damage and inflammation, as well as reduced alveolar macrophage phagocytic capability, which may increase the risk of infection. Pulmonary complications, such as respiratory failure, pneumonia, pleural effusions, acute respiratory distress syndrome, lung oedema, and pulmonary embolism from venous thromboembolism, are common and found to be among the major causes of death in this group of patients. Furthermore, over the past two decades, tracheostomy use has increased among stroke patients, who can have unique indications for this procedure-depending on the location and type of stroke-when compared to the general population. However, the optimal mechanical ventilator strategy remains unclear in this population. Although a high tidal volume (VT) strategy has been used for many years, the latest evidence suggests that a protective ventilatory strategy (VT = 6-8 mL/kg predicted body weight, positive end-expiratory pressure and rescue recruitment manoeuvres) may also have a role in brain-damaged patients, including those with stroke. The aim of this narrative review is to explore the pathophysiology of brain-lung interactions after acute ischaemic stroke and the management of mechanical ventilation in these patients.

Host-pathogen interaction during mechanical ventilation: systemic or compartmentalized response?

Patients admitted to the intensive care unit (ICU) often require invasive mechanical ventilation. Ventilator-associated lower respiratory tract infections (VA-LRTI), either ventilator-associated tracheobronchitis (VAT) or ventilator-associated pneumonia (VAP), are the most common complication among this patient cohort. VAT and VAP are currently diagnosed and treated as separate entities, viewed as binary disease elements despite an inherent subjectivity in distinguishing them clinically. This paper describes a new approach to pulmonary infections in critically ill patients. Our conjecture is that the host-pathogen interaction during mechanical ventilation determines a local compartmentalized or systemic de-compartmentalized response, based on host immunity and inflammation, and the pathogenic potential of the infecting organism. This compartmentalized or de-compartmentalized response establishes disease severity along a continuum of colonization, VAT or VAP. This change in approach is underpinned by the dissemination hypothesis, which acknowledges the role of immune and inflammatory systems in determining host response to pathogenic organisms in the lower respiratory tract. Those with intact immune and inflammatory pathways may limit infection to a compartmentalized VAT, while immunosuppressed mechanically ventilated patients are at greater risk of a de-compartmentalized VAP. Taking this model from the realm of theory to the bedside will require a greater understanding of inflammatory and immune pathways, and the development of novel disease-specific biomarkers and diagnostic techniques. Advances will lead to early initiation of optimal bespoke antimicrobial therapy, where the intensity and duration of therapy are tailored to clinical, immune and biomarker response. This approach will benefit towards a personalized treatment.

Calorie Intake During Status Epilepticus and Outcome: A 5-Year Cohort Study.

OBJECTIVES: Recommendations regarding nutrition during status epilepticus are lacking, and it is unclear whether restriction of calorie intake would result in beneficial effects or potential harm. We thus aimed to investigate associations between daily calorie intake and outcome in adult status epilepticus patients deriving from a 5-year cohort with a systematic and prospective collection of nutritional data. DESIGN: Retrospective observational study. SETTING: Medical ICUs at a tertiary academic medical care center. PATIENTS: Consecutive patients with status epilepticus treated at the ICUs from 2012 to 2016 were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All patients with status epilepticus were monitored regarding nutrition support provided according to the guidelines. Relative risks of no return to baseline were estimated by Poisson regression with robust error variance and adjusted for potential confounders. Of 203 patients, 86 (42%) had return to baseline. Metabolic characteristics of patients with and without return to baseline did not differ. Patients without return to baseline received more calories and proteins per status epilepticus day, and increasing nutritional support was associated with ventilator-associated pneumonia (relative risk, 1.19; 95% CI, 1.09-1.28). Multivariable regression analysis revealed significant increases in relative risks for no return to baseline with every percent of days with nutrition (relative risk, 1.35; 95% CI, 1.05-1.74), with every 100 kcal (relative risk, 1.01; 95% CI, 1.002-1.01), and gram of protein intake (relative risk, 1.01; 95% CI, 1.001-1.01) per status epilepticus day, independent of potential confounders (including fatal etiology, duration and severity of status epilepticus, Charlson comorbidity index, and treatment with anesthetics). CONCLUSIONS: Our results indicate that increased calorie intake during status epilepticus is independently associated with unfavorable outcome. These findings require further validation and investigations into potential mediators, such as induction of ketogenesis, immunomodulating effects, and/or reduction of ICU-associated complications, such as infections.

Impact of bronchial colonization with Candida spp. on the risk of bacterial ventilator-associated pneumonia in the ICU: the FUNGIBACT prospective cohort study.

INTRODUCTION: Respiratory tract Candida spp. colonization is associated with more frequent bacterial ventilator-associated pneumonia (VAP). However, this colonization could be causally related to VAP or simply reflect the immune paralysis associated with multiple organ failure. OBJECTIVE: To prospectively evaluate the relationship between Candida spp. colonization and bacterial VAP in mechanically ventilated patients with multiple organ failure. INCLUSION: Patients receiving mechanical ventilation for > 4 days and presenting multiple organ failure were included. Tracheal colonization with Candida spp. was evaluated at inclusion (day 0, D0) and every 4 days until extubation. Quantitative proximal and tracheal cultures were performed at each VAP episode. Monocyte human leukocyte antigen-DR isotype (mHLA-DR) expression and the ratio of polymononuclear leukocytes to lymphocytes were used to evaluate immunoparalysis at D0 and D7. The relationship between fungal colonization and VAP was modelled using cause-specific models for repeated events with adjustment for time-dependent confounders and immune factors. RESULTS: A total of 213 patients, with a median age of 64, simplified acute physiology score II (SAPS II) score 55 and sequential organ failure assessment (SOFA) score 10, mainly admitted for medical reasons (n = 197, 92%), were enrolled in 2012-2015. The median ICU stay was 24 days and the mortality rate was 32% (69 cases). Median mHLA-DR was 5916 Ab-bound/cell [3863-8934]; median lymphocyte count, 0.9Giga/L [0.6-1.3]; neutrophil-to-lymphocyte ratio, 10.9 [6.5-19.7]. Overall, 146 cases (68.5%) had tracheal colonization with Candida spp. An episode of VAP occurred (either for the first or only time) in 62 (29.1%) cases 5.5 days (median) after D0; a second episode occurred in 12 (5.6%) cases, 15.5 days (median) after D0. After adjustment, bronchial colonization with Candida was not associated with VAP [adjusted cause-specific hazard ratio = 0.98 (0.59-1.65), p = 0.95]. CONCLUSION: In patients with mechanical ventilation for more than 4 days and multiple organ failure, bronchial colonization with Candida spp. was not associated with VAP, even after adjustment for immune function.

Machine Learning Methods Applied to Predict Ventilator-Associated Pneumonia with Pseudomonas aeruginosa Infection via Sensor Array of Electronic Nose in Intensive Care Unit.

One concern to the patients is the off-line detection of pneumonia infection status after using the ventilator in the intensive care unit. Hence, machine learning methods for ventilator-associated pneumonia (VAP) rapid diagnose are proposed. A popular device, Cyranose 320 e-nose, is usually used in research on lung disease, which is a highly integrated system and sensor comprising 32 array using polymer and carbon black materials. In this study, a total of 24 subjects were involved, including 12 subjects who are infected with pneumonia, and the rest are non-infected. Three layers of back propagation artificial neural network and support vector machine (SVM) methods were applied to patients' data to predict whether they are infected with VAP with Pseudomonas aeruginosa infection. Furthermore, in order to improve the accuracy and the generalization of the prediction models, the ensemble neural networks (ENN) method was applied. In this study, ENN and SVM prediction models were trained and tested. In order to evaluate the models' performance, a fivefold cross-validation method was applied. The results showed that both ENN and SVM models have high recognition rates of VAP with Pseudomonas aeruginosa infection, with 0.9479 ± 0.0135 and 0.8686 ± 0.0422 accuracies, 0.9714 ± 0.0131, 0.9250 ± 0.0423 sensitivities, and 0.9288 ± 0.0306, 0.8639 ± 0.0276 positive predictive values, respectively. The ENN model showed better performance compared to SVM in the recognition of VAP with Pseudomonas aeruginosa infection. The areas under the receiver operating characteristic curve of the two models were 0.9842 ± 0.0058 and 0.9410 ± 0.0301, respectively, showing that both models are very stable and accurate classifiers. This study aims to assist the physician in providing a scientific and effective reference for performing early detection in Pseudomonas aeruginosa infection or other diseases.

Early-Onset Ventilator-Associated Pneumonia in Severe Traumatic Brain Injury: is There a Relationship with Prehospital Airway Management?

BACKGROUND: Prehospital airway management in severe traumatic brain injury (TBI) is widely recommended by international guidelines for the management of trauma. Early-onset ventilator-associated pneumonia (EOVAP) is a common occurrence in this population and can worsen mortality and functional outcome. OBJECTIVES: In this retrospective observational study, we aimed to evaluate the association between different prehospital airway management variables and the occurrence of EOVAP. Secondarily we evaluated the correlation between EOVAP and mortality and neurological outcome. METHODS: The study retrospectively evaluated 223 patients admitted from 2010 to 2017 in our trauma intensive care unit for severe TBI. The population was divided into three groups on the basis of the airway management technique adopted (bag mask ventilation, laryngeal tube, orotracheal intubation). Uni- and multivariate logistic regression analyses were performed using the occurrence of EOVAP as the dependent variable, to investigate potential associations with prehospital airway management. RESULTS: A total of 131 episodes (58.7%) of EOVAP were registered in the study population (223 patients). Laryngeal tube and orotracheal intubation were used in patients with significantly lower Glasgow Coma Scale score on scene and a higher Face Abbreviated Injury Scale; advanced airway management significantly increased the total rescue time. The prehospital airway management technique adopted, prehospital type of sedation or use of muscle relaxants, type of transport, and rescue times were not associated with the occurrence of EOVAP. CONCLUSIONS: Prehospital airway management does not have a significant impact on the occurrence of EOVAP in severe TBI patients. Similarly, it does not have a significant impact on mortality or long-term neurological outcome despite increasing duration of mechanical ventilation, intensive care unit, and hospital stay.

Diagnostic Efficacy of Serum Amyloid A Protein and Soluble Intercellular Adhesion Molecule 1 in Pediatric Ventilator-Associated Pneumonia.

OBJECTIVES: Study of inflammatory biomarkers which may aid in early detection of ventilator-associated pneumonia (VAP) in children and predicting their outcome. PATIENTS: Thirty-five children, aged 2 months to 13 years, needed mechanical ventilation (MV) for more than 48 hours due to causes other than pneumonia. METHODS: Measurement of serum amyloid A (SAA) protein, soluble intercellular adhesion molecule 1 (sICAM-1), and C-reactive protein (CRP), modified clinical pulmonary infection score (CPIS) and performing culture of endotracheal aspirate at the start and on the third day of MV. RESULTS: Ventilator-associated pneumonia was diagnosed by CPIS in 6 (17.1%) of 35 patients. On the third day of MV, there was a significant increase in serum mean levels of SAA, sICAM-1, and CRP in comparison to the start of MV ( P = .005, .004, and .01, respectively). Three (50%) of 6 patients with VAP died, while 4 (14.28%) of 28 patients without VAP died. The sensitivity of serum SAA, sICAM-1, and CPIS were 100% for predicting VAP, while specificity was highest for CPIS (96.55%) followed by SAA (93.1%). Combination of CPIS and SAA increased the specificity to 100%. For predicting nonsurvival, serum SAA and sICAM-1 had a sensitivity of 100% and a specificity of 92.86% and 89.29%, respectively. CONCLUSION: Serum amyloid A and sICAM-1 may be considered as reliable markers for detection of VAP. Combination of serum SAA with CPIS increased the specificity to 100%. Measurement of SAA in patients with VAP also had a good predictive value for nonsurvival in such patients.

Postoperative Pneumonia Prevention in Pulmonary Resections: A Feasibility Pilot Study.

BACKGROUND: Pneumonia after pulmonary resection occurs in 5% to 12% of patients and causes substantial morbidity. Oral hygiene regimens lower the incidence of ventilator-associated pneumonias; however, the impact in patients undergoing elective pulmonary resection is unknown. We conducted a prospective pilot study to assess the feasibility of an oral hygiene intervention in this patient cohort. METHODS: Patients undergoing elective pulmonary resection were prospectively enrolled in a single-arm interventional study with time-matched controls. Participants were asked to brush their teeth with 0.12% chlorhexidine three times daily for 5 days before their operations and 5 days or until the time of discharge after their operations. Patients were eligible if they had known or suspected lung cancer and were undergoing (1) any anatomic lung resection or (2) a wedge resection with forced expiratory volume in 1 second or diffusing capacity of lung for carbon monoxide less than 50% predicted. RESULTS: Sixty-two patients were enrolled in the pilot intervention group and compared with a contemporaneous cohort of 611 patients who met surgical inclusion criteria. Preoperative adherence to the chlorhexidine toothbrushing regimen was high: median 100% (interquartile range: 87% to 100%). Postoperatively, 80% of patients continued toothbrushing, whereas 20% declined further participation. Among those who participated postoperatively, median adherence was 86% (interquartile range: 53% to 100%). There was a trend toward reduction in postoperative pneumonia: 1.6% (1 of 62) in the intervention cohort versus 4.9% (30 of 611) in the time-matched cohort (p = 0.35). The number needed to treat to prevent one case of pneumonia was 30 patients. CONCLUSIONS: This pilot study demonstrated patients can comply with an inexpensive perioperative oral hygiene regimen that may be promising for reducing morbidity (Clinical Trials Registry: NCT01446874).

Neutrophil extracellular traps (NETs) are increased in the alveolar spaces of patients with ventilator-associated pneumonia.

BACKGROUND: Neutrophils release neutrophil extracellular traps (NETs) in response to invading pathogens. Although NETs play an important role in host defense against microbial pathogens, they have also been shown to play a contributing mechanistic role in pathologic inflammation in the absence of infection. Although a role for NETs in bacterial pneumonia and acute respiratory distress syndrome (ARDS) is emerging, a comprehensive evaluation of NETs in the alveolar space of critically ill patients has yet to be reported. In this study, we evaluated whether markers of NET formation in mechanically ventilated patients are associated with ventilator-associated pneumonia (VAP). METHODS: We collected bronchoalveolar lavage fluid from 100 critically ill patients undergoing bronchoscopy for clinically suspected VAP. Subjects were categorized by the absence or presence of VAP and further stratified by ARDS status. NETs (myeloperoxidase (MPO)-DNA complexes) and the NET-associated markers peroxidase activity and cell-free DNA were analyzed by enzyme-linked immunosorbent assay and colorimetric assays, respectively. Quantitative polymerase chain reaction of nuclear and mitochondrial DNA was used to determine the origin of the extruded DNA. Interleukin (IL)-8 and calprotectin were assayed as measures of alveolar inflammation and neutrophil activation. Correlations between NETs and markers of neutrophil activation were determined using Spearman's correlation. We tested for associations with VAP and bacterial burden by logistic and linear regression, respectively, using log10-transformed NETs. RESULTS: MPO-DNA concentrations were highly correlated with other measures of NET formation in the alveolar space, including cell-free DNA and peroxidase activity (r = 0.95 and r = 0.87, p < 0.0001, respectively). Alveolar concentrations of MPO-DNA were higher in subjects with VAP and ARDS compared with those with ARDS alone (p < 0.0001), and higher MPO-DNA was associated with increased odds of VAP (odds ratio 3.03, p < 0.0001). In addition, NET concentrations were associated with bacterial burden (p < 0.0001) and local alveolar inflammation as measured by IL-8 (r = 0.89, p < 0.0001). CONCLUSIONS: Alveolar NETs measured by MPO-DNA complex are associated with VAP, and markers of NETosis are associated with local inflammation and bacterial burden in the lung. These results suggest that NETs contribute to inflammatory responses involved in the pathogenesis of VAP.

Profiling inflammatory markers in patients with pneumonia on intensive care.

Clinical investigations lack predictive value when diagnosing pneumonia, especially when patients are ventilated and develop ventilator associated pneumonia (VAP). New tools to aid diagnosis are important to improve outcomes. This pilot study examines the potential for a panel of inflammatory mediators to aid in the diagnosis. Forty-four ventilated patients, 17 with pneumonia and 27 with brain injuries, eight of whom developed VAP, were recruited. 51 inflammatory mediators, including cytokines and oxylipins, were measured in patients' serum using flow cytometry and mass spectrometry. The mediators could separate patients admitted to ICU with pneumonia compared to brain injury with an area under the receiver operating characteristic curve (AUROC) 0.75 (0.61-0.90). Changes in inflammatory mediators were similar in both groups over the course of ICU stay with 5,6-dihydroxyeicosatrienoic and 8,9-dihydroxyeicosatrienoic acids increasing over time and interleukin-6 decreasing. However, brain injured patients who developed VAP maintained inflammatory profiles similar to those at admission. A multivariate model containing 5,6-dihydroxyeicosatrienoic acid, 8,9-dihydroxyeicosatrienoic acid, intercellular adhesion molecule-1, interleukin-6, and interleukin-8, could differentiate patients with VAP from brain injured patients without infection (AUROC 0.94 (0.80-1.00)). The use of a selected group of markers showed promise to aid the diagnosis of VAP especially when combined with clinical data.

Prognostic Risk Factors in Ventilator-Associated Pneumonia.

BACKGROUND Ventilator-associated pneumonia (VAP) is a nosocomial infection commonly seen in patients in intensive care units (ICU). This study aimed to analyze factors affecting prognosis of patients diagnosed with VAP. MATERIAL AND METHODS Critically ill patients with VAP were retrospectively evaluated between June 2002 and June 2011 in the ICU. VAP diagnosis was made according to 2005 ATS/IDSA (Infectious Diseases Society of America/American Thoracic Society) criteria. First pneumonia attacks of patients were analyzed. RESULTS When early- and late-onset pneumonia causes were compared according to ICU and hospital admittance, resistant bacteria were found to be more common in pneumonias classified as early-onset according to ICU admittance. APACHE II score of >21 (p=0.016), SOFA score of >6 (p<0.001) on admission to ICU and SOFA score of >6 (p<0.001) on day of diagnosis are risk factors affecting mortality. Additionally, low PaO2/FIO2 ratio at onset of VAP had a negative effect on prognosis (p<0.001). SOFA score of >6 on the day of VAP diagnosis was an independent risk factor for mortality [(p<0.001; OR (95%CI): 1.4 (1.2-1.6)]. CONCLUSIONS Resistant bacteria might be present in early-onset VAP. Especially, taking LOS into consideration may better estimate the presence of resistant bacteria. Acinetobacter baumannii, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus (MRSA) were the most frequent causative microorganisms for VAP. SOFA score might be more valuable than APACHE II score. Frequently surveilling SOFA scores may improve predictive performance over time.

Pathophysiology of Escherichia coli pneumonia: Respective contribution of pathogenicity islands to virulence.

Ventilator-associated pneumonia (VAP) remains the most frequent life-threatening nosocomial infection. Enterobacteriaceae including Escherichia coli are increasingly involved. If a cumulative effect of pathogenicity islands (PAIs) has been shown for E. coli virulence in urinary tract or systemic infections, very little is known regarding pathophysiology of E. coli pneumonia. This study aimed to determine the role of each of the 7 PAIs present in pathogenic E. coli strain 536 in pneumonia pathophysiology. We used mutant strains to screen pathophysiological role of PAI in a rat pneumonia model. We also test individual gene mutants within PAI identified to be involved in pneumonia pathogenesis. Finally, we determined the prevalence of these genes of interest in E. coli isolates from feces and airways of ventilated patients. Only PAIs I and III were significantly associated with rat pneumonia pathogenicity. Only the antigen-43 (Ag43) gene in PAI III was significantly associated with bacterial pathogenicity. The prevalence of tested genes in fecal and airway isolates of ventilated patients did not differ between isolates. In contrast, genes encoding Ag43, the F17-fimbriae subunits, HmuR and SepA were more prevalent in VAP isolates with statistical significance for hmuR when compared to airway colonizing isolates. The E. coli PAIs involved in lung pathogenicity differed from those involved in urinary tract and bloodstream infections. Overall, extraintestinal E. coli virulence seems to rely on a combination of numerous virulence genes that have a cumulative effect depending on the infection site.

The study of vitamin D administration effect on CRP and Interleukin-6 as prognostic biomarkers of ventilator associated pneumonia.

PURPOSE: In regard with the effect of immune-stimulants in the treatment of infectious diseases, the effect of vitamin D administration on the outcome of patients with Ventilator-Associated Pneumonia (VAP) with a high rate of mortality, was studied. MATERIAL AND METHOD: In this trial, 46 adult patients suffering from VAP and vitamin D deficiency were enrolled. The first group of patients received single intramuscular injection of vitamin D (300000Unit), while the other group were given the placebo. RESULTS: Administration of vitamin D significantly enhanced its levels (P<0.0001) in the treated patients (12.28±8.26) in comparison with placebo group (1.15±1.50). Serum Interleukin-6 levels were significantly reduced in the treated group compared to placebo (P=0.01). Although C-Reactive protein (CRP) levels showed an improving trend in the vitamin D group, no significant difference between groups (P=0.12) was found. Interestingly, the mortality rate of patients that treated with vitamin D (5/24) was significantly lower (p=0.04) than that of the placebo group (11/22). CONCLUSION: Our results indicate that vitamin D administration can significantly reduce the IL-6 as prognostic marker in VAP patients, and must be considered as adjunct option in the treatment of VAP patients.