Diagnosis of ventilator-associated pneumonia in critically ill adult patients-a systematic review and meta-analysis

Diagnostic Role of Opsonic Activity in Acinetobacter baumannii Ventilator-Associated Pneumonia

In this study, we investigated the diagnostic value of opsonic activity against Acinetobacter baumannii in Ventilator-Associated Pneumonia (VAP) among 50 patients, compared to 102 negative and positive controls. Out of the 50 patients, only 33 (66 %) were diagnosed with VAP using the Clinical Pulmonary Infection Score (CPIS). The opsonic activity assay demonstrated three key findings: (i) 95 % sensitivity and 91.7 % specificity, with a Receiver Operating Characteristic (ROC) area of 0.976 for distinguishing A. baumannii culture positives from negatives; (ii) 95 % sensitivity and 78.7 % specificity, with a 0.915 ROC area, in differentiating VAP/blood culture positive patients from colonized/negative groups; (iii) An ROC area of 0.553 for VAP and colonization, as identified by CPIS alone, indicating an indeterminate threshold. These results highlight that CPIS, microbiological, and clinical evaluations were not correlated, suggesting that opsonic activity against A. baumannii could be a potential VAP diagnostic tool, with the need for large-scale validations.

Improving Outcomes in Nosocomial Pneumonia: Recent Evidence and More Challenges

Nosocomial pneumonia (NP) represents a leading nosocomial infection and results in substantial morbidity and cost. Over the last several years, the evidence has evolved which directs our approach to NP. Specifically, the definition of NP and classification of its various subtypes has expanded to capture nuances among various phenotypes of this syndrome. For example, segregating those with hospital-acquired pneumonia (HAP) based on whether they subsequently require mechanical ventilation has been shown to be important. Likewise, newer data indicate the true economic cost of NP and underscore the diverse range of pathogens that can cause NP. Moreover, multidrug-resistant (MDR) bacteria have become a major threat in NP. Fortunately, newer simple preventive strategies have been tested and found to be effective at reducing the incidence of NP. Should prevention fail, a range of new antibiotics have been formally studied in NP and found to be effective. Some of these novel agents have relatively broad ranges of activity and are in vitro active against select MDR organisms. Others, however, are narrower in spectrum and directed against specific problem bacteria. In short, the literature in the field of NP has progressed rapidly, and clinicians require a clear appreciation of these changes so as to improve patient outcomes.

Hospital-acquired bacterial pneumonia in critically ill patients: from research to clinical practice

INTRODUCTION

Hospital-acquired pneumonia (HAP) represents a significant cause of mortality among critically ill patients admitted to Intensive Care Units (ICUs). Timely and precise diagnosis is imperative to enhance therapeutic efficacy and patient outcomes. However, the diagnostic process is challenged by test limitations and a wide-ranging list of differential diagnoses, particularly in patients exhibiting escalating oxygen requirements, leukocytosis, and increased secretions.

AREAS COVERED

This narrative review aims to update diagnostic modalities, facilitating the prompt identification of nosocomial pneumonia while guiding, developing, and assessing therapeutic interventions. A comprehensive literature review was conducted utilizing the MEDLINE/PubMed database from 2013 to April 2024.

EXPERT OPINION

An integrated approach that integrates clinical, microbiological, and imaging tools is paramount. Progress in diagnostic techniques, including novel molecular methods, the expanding utilization and accuracy of bedside ultrasound, and the emergence of Artificial Intelligence, coupled with an improved comprehension of lung microbiota and host-pathogen interactions, continues to enhance our capability to accurately and swiftly identify HAP and its causative agents. This advancement enables the refinement of treatment strategies and facilitates the implementation of precision medicine approaches.

The Clinical Pulmonary Infection Score Combined with Procalcitonin and Lung Ultrasound (CPIS-PLUS), a Good Tool for Ventilator Associated Pneumonia Early Diagnosis in Pediatrics

Ventilator-associated pneumonia (VAP) is common in Pediatric Intensive Care Units. Although early detection is crucial, current diagnostic methods are not definitive. This study aimed to identify lung ultrasound (LUS) findings and procalcitonin (PCT) values in pediatric patients with VAP to create a new early diagnosis score combined with the Clinical Pulmonary Infection Score (CPIS), the CPIS-PLUS score. Prospective longitudinal and interventional study. Pediatric patients with suspected VAP were included and classified into VAP or non-VAP groups, based on Centers of Disease Control (CDC) criteria for the final diagnosis. A chest-X-ray (CXR), LUS, and blood test were performed within the first 12 h of admission. CPIS score was calculated. A total of 108 patients with VAP suspicion were included, and VAP was finally diagnosed in 51 (47%) patients. CPIS-PLUS showed high accuracy in VAP diagnosis with a sensitivity (Sn) of 80% (95% CI 65-89%) and specificity (Sp) of 73% (95% CI 54-86%). The area under the curve (AUC) resulted in 0.86 for CPIS-PLUS vs. 0.61 for CPIS. In conclusion, this pilot study showed that CPIS-PLUS could be a potential and reliable tool for VAP early diagnosis in pediatric patients. Internal and external validations are needed to confirm the potential value of this score to facilitate VAP diagnosis in pediatric patients.

Ceftriaxone to prevent early ventilator-associated pneumonia in patients with acute brain injury: a multicentre, randomised, double-blind, placebo-controlled, assessor-masked superiority trial

BACKGROUND

Patients with acute brain injury are at high risk of ventilator-associated pneumonia (VAP). The benefit of short-term antibiotic prophylaxis remains debated. We aimed to establish the effect of an early, single dose of the antibiotic ceftriaxone on the incidence of early VAP in patients with severe brain injury who required mechanical ventilation.

METHODS

PROPHY-VAP was a multicentre, randomised, double-blind, placebo-controlled, assessor-masked, superiority trial conducted in nine intensive care units in eight French university hospitals. We randomly assigned comatose (Glasgow Coma Scale score [GCS] ≤12) adult patients (age ≥18 years) who required mechanical ventilation for at least 48 h after acute brain injury to receive intravenous ceftriaxone 2 g or placebo once within the 12 h following tracheal intubation. Participants did not receive selective oropharyngeal and digestive tract decontamination. The primary outcome was the proportion of patients developing early VAP from the 2nd to the 7th day of mechanical ventilation, confirmed by masked assessors. The analysis was reported in the modified intention-to-treat population, which comprised all randomly assigned patients except those who withdrew or did not give consent to continue and those who did not receive the allocated treatment because they met a criterion for non-eligibility. The trial is registered with ClinicalTrials.gov, NCT02265406.

FINDINGS

From Oct 14, 2015, to May 27, 2020, 345 patients were randomly assigned (1:1) to receive ceftriaxone (n=171) or placebo (n=174); 330 received the allocated intervention and 319 were included in the analysis (162 in the ceftriaxone group and 157 in the placebo group). 166 (52%) participants in the analysis were men and 153 (48%) were women. 15 patients did not receive the allocated intervention after randomisation and 11 withdrew their consent. Adjudication confirmed 93 cases of VAP, including 74 early infections. The incidence of early VAP was lower in the ceftriaxone group than in the placebo group (23 [14%] vs 51 [32%]; hazard ratio 0·60 [95% CI 0·38-0·95], p=0·030), with no microbiological impact and no adverse effects attributable to ceftriaxone.

INTERPRETATION

In patients with acute brain injury, a single ceftriaxone dose decreased the risk of early VAP. On the basis of our findings, we recommend that an early, single dose of ceftriaxone be included in all bundles for the prevention of VAP in patients with brain injury who require mechanical ventilation.

FUNDING

French Ministry of Social Affairs and Health.

Ventilator-associated pneumonia related to extended-spectrum beta-lactamase producing Enterobacterales during severe acute respiratory syndrome coronavirus 2 infection: risk factors and prognosis

BACKGROUND

Patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-COV 2) and requiring mechanical ventilation suffer from a high incidence of ventilator associated pneumonia (VAP), mainly related to Enterobacterales. Data regarding extended-spectrum beta-lactamase producing Enterobacterales (ESBL-E) VAP are scarce. We aimed to investigate risk factors and outcomes of ESBL-E related VAP among critically ill coronavirus infectious disease-19 (COVID-19) patients who developed Enterobacterales related VAP.

PATIENTS AND METHODS

We performed an ancillary analysis of a multicenter prospective international cohort study (COVID-ICU) that included 4929 COVID-19 critically ill patients. For the present analysis, only patients with complete data regarding resistance status of the first episode of Enterobacterales related VAP (ESBL-E and/or carbapenem-resistant Enterobacterales, CRE) and outcome were included.

RESULTS

We included 591 patients with Enterobacterales related VAP. The main causative species were Enterobacter sp (n = 224), E. coli (n = 111) and K. pneumoniae (n = 104). One hundred and fifteen patients (19%), developed a first ESBL-E related VAP, mostly related to Enterobacter sp (n = 40), K. pneumoniae (n = 36), and E. coli (n = 31). Eight patients (1%) developed CRE related VAP. In a multivariable analysis, African origin (North Africa or Sub-Saharan Africa) (OR 1.7 [1.07-2.71], p = 0.02), time between intubation and VAP (OR 1.06 [1.02-1.09], p = 0.002), PaO2/FiO2 ratio on the day of VAP (OR 0.997 [0.994-0.999], p = 0.04) and trimethoprim-sulfamethoxazole exposure (OR 3.77 [1.15-12.4], p = 0.03) were associated with ESBL-E related VAP. Weaning from mechanical ventilation and mortality did not significantly differ between ESBL-E and non ESBL-E VAP.

CONCLUSION

ESBL-related VAP in COVID-19 critically-ill patients was not infrequent. Several risk factors were identified, among which some are modifiable and deserve further investigation. There was no impact of resistance of the first Enterobacterales related episode of VAP on outcome.

Clinical challenge of diagnosing non-ventilator hospital-acquired pneumonia and identifying causative pathogens: a narrative review

Non-ventilated hospital-acquired pneumonia (NV-HAP) is associated with a significant healthcare burden, arising from high incidence and associated morbidity and mortality. However, accurate identification of cases remains challenging. At present, there is no gold-standard test for the diagnosis of NV-HAP, requiring instead the blending of non-specific signs and investigations. Causative organisms are only identified in a minority of cases. This has significant implications for surveillance, patient outcomes and antimicrobial stewardship. Much of the existing research in HAP has been conducted among ventilated patients. The paucity of dedicated NV-HAP research means that conclusions regarding diagnostic methods, pathology and interventions must largely be extrapolated from work in other settings. Progress is also limited by the lack of a widely agreed definition for NV-HAP. The diagnosis of NV-HAP has large scope for improvement. Consensus regarding a case definition will allow meaningful research to improve understanding of its aetiology and the heterogeneity of outcomes experienced by patients. There is potential to optimize the role of imaging and to incorporate novel techniques to identify likely causative pathogens. This would facilitate both antimicrobial stewardship and surveillance of an important healthcare-associated infection. This narrative review considers the utility of existing methods to diagnose NV-HAP, with a focus on the significance and challenge of identifying pathogens. It discusses the limitations in current techniques, and explores the potential of emergent molecular techniques to improve microbiological diagnosis and outcomes for patients.

Data quality review of the Brazilian nosocomial infections surveillance system

BACKGROUND

Surveillance of healthcare-associated infections (HAIs) is an essential component of hospital infection prevention and control systems. We aimed to assess the quality of the data compiled by the Brazilian HAI Surveillance System from pediatric (PICUs) and neonatal intensive care units (NICUs), between 2012 and 2021.

METHODS

Data Quality Review, including adherence, completeness, internal consistency, consistency over time, and consistency of population trend, were computed at both national and state levels based on quality metrics from World Health Organization Toolkit. Incidence rates (or incidence density) of ventilator-associated pneumonia (VAP) and central line-associated bloodstream infection (CLABSI) were obtained from the Brazilian National Nosocomial Infections Surveillance (NNIS) system. Data on sepsis-related mortality, spanning the period from 2012 to 2021, were extracted from the Brazilian National Health Service database (DATASUS). Additionally, correlations between sepsis-related mortality and incidence rates of VAP or CLABSI were calculated.

RESULTS

Throughout the majority of the study period, adherence to VAP reporting remained below 75%, exhibiting a positive trend post-2016. Widespread outliers, as well as inconsistencies over time and in population trends, were evident across all 27 states. Only four states maintained consistent adherence levels above 75% for more than 8 years regarding HAI incidence rates. Notably, CLABSI in NICUs boasted the highest reporting adherence among all HAIs, with 148 periods out of 270 (54.8%) exhibiting reporting adherence surpassing 75%. Three states achieved commendable metrics for CLABSI in PICUs, while five states demonstrated favorable results for CLABSI in NICUs.

CONCLUSIONS

While adherence to HAI report is improving among Brazilian states, an important room for improvement in the Brazilian NNIS exists. Additional efforts should be made by the Brazilian government to improve the reliability of HAI data, which could serve as valuable guidance for hospital infection prevention and control policies.

Assessing Respiratory Tract Infections' Prevalence and Microbial Profiles in Mechanically Ventilated Patients: Insights From Broncho Alveolar Lavage Examination

Introduction Chest infections represent a significant challenge in mechanically ventilated patients, often leading to adverse outcomes despite advancements in critical care. This prospective study was conducted in the intensive care unit of tertiary referral care, with objectives to assess chest infection prevalence, microbial profiles, and outcomes in mechanically ventilated patients through broncho-alveolar lavage (BAL) examination. Methodology This prospective study involved 38 patients aged 15 to 65 years who were receiving mechanical ventilation and underwent BAL. The procedure of BAL was followed as per the guidelines and recommendations outlined by the American Thoracic Society for Bronchoscopic Lavage. Microbial analysis involves the use of microscopic examination and quantitative culture methods. Different staining techniques were utilized to identify bacteria, fungi, and mycobacteria. Complications and adverse events were monitored and recorded. Results Out of the 38 patients who underwent BAL, the majority, 30 (78.94%), were found to have chest infections, with gram-negative bacteria, including Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii, being the causative agents. The antibiotic sensitivity profiles indicated that the organisms were susceptible to carbapenems and broad-spectrum β-lactam/β-lactamase inhibitor combinations while showing resistance to fluoroquinolones. Despite adequate treatment, mortality remained significant in 12 (31.57%) patients. Conclusion Study findings underscore the importance of proactive surveillance, early diagnosis, and targeted management strategies to mitigate the burden of respiratory infections in critical care settings.

Comparison of bacteremic pneumonia caused by Escherichia coli and Klebsiella pneumoniae: A retrospective study

OBJECTIVES

To compare the prognosis of bacteremic pneumonia caused by Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli) pathogens.

METHODS

A retrospective analysis was carried out on the clinical data of 162 patients who were diagnosed with bacterial pneumonia caused by either K. pneumoniae or E. coli between 2016-2019. The primary outcome of the analysis was the patients' 30-day mortality rate.

RESULTS

There were 82 patients in the E. coli bacteremic pneumonia (E. coli-BP) group and 80 patients in the K. pneumoniae bacteremic pneumonia (KP-BP) group. The 30-day mortality rate was 43.75% (n=35/80) in the KP-BP group and 21.95% (n=18/82) in the E. coli-BP group (p<0.001). Following the adjustment for confounding variables in 4 distinct models, the hazard ratios for the primary outcome in KP-BP were determined to be 0.70 (95% confidence interval [CI]: [0.44-1.02]) in Model 1, 0.72 (95% CI: [0.46-1.14]) in Model 2, 0.99 (95% CI: [0.57-1.73]) in Model 3, and 1.22 (95% CI: [0.69-2.18]) in Model 4.

CONCLUSION

Patients diagnosed with KP-BP exhibited a similar prognosis as those diagnosed with E. coli-BP. For patients with KP-BP, the risk of mortality was significantly higher for those who were in the intensive care unit, were infected with carbapenem-resistant strains, or had a high sequential organ failure assessment score. In patients with E. coli-BP, the Pitt bacteremia score was strongly associated with the 30-day mortality rate.

Immediate vs. culture-initiated antibiotic therapy in suspected non-severe ventilator-associated pneumonia: a before-after study (DELAVAP)

BACKGROUND

Ventilator-associated pneumonia (VAP) is the leading nosocomial infection in critical care and is associated with adverse outcomes. When VAP is suspected, starting antibiotic therapy (AT) immediately after pulmonary sampling may expose uninfected patients to unnecessary treatment, whereas waiting for bacteriological confirmation may delay AT in infected patients. As no robust data exist to choose between these strategies, the decision must balance the pre-test diagnostic probability, clinical severity, and risk of antimicrobial resistance. The objective of this study in patients with suspected non-severe VAP was to compare immediate AT started after sampling to conservative AT upon receipt of positive microbiological results. The outcomes were antibiotic sparing, AT suitability, and patient outcomes.

METHODS

This single-center, before-after study included consecutive patients who underwent distal respiratory sampling for a first suspected non-severe VAP episode (no shock requiring vasopressor therapy or severe acute respiratory distress syndrome). AT was started immediately after sampling in 2019 and upon culture positivity in 2022 (conservative strategy). The primary outcome was the number of days alive without AT by day 28. The secondary outcomes were mechanical ventilation duration, day-28 mortality, and AT suitability (active necessary AT or spared AT).

RESULTS

The immediate and conservative strategies were applied in 44 and 43 patients, respectively. Conservative and immediate AT were associated with similar days alive without AT (median [interquartile range], 18.0 [0-21.0] vs. 16.0 [0-20.0], p = 0.50) and without broad-spectrum AT (p = 0.53) by day 28. AT was more often suitable in the conservative group (88.4% vs. 63.6%, p = 0.01), in which 27.9% of patients received no AT at all. No significant differences were found for mechanical ventilation duration (median [95%CI], 9.0 [6-19] vs. 9.0 [6-24] days, p = 0.65) or day-28 mortality (hazard ratio [95%CI], 0.85 [0.4-2.0], p = 0.71).

CONCLUSION

In patients with suspected non-severe VAP, waiting for microbiological confirmation was not associated with antibiotic sparing, compared to immediate AT. This result may be ascribable to low statistical power. AT suitability was better with the conservative strategy. None of the safety outcomes differed between groups. These findings would seem to allow a large, randomized trial comparing immediate and conservative AT strategies.

Ceragenin-coated endotracheal tubes for the reduction of ventilator-associated pneumonia: a prospective, longitudinal, cross-over, interrupted time, implementation study protocol (CEASE VAP study)

BACKGROUND

Critically ill patients are at high risk of acquiring ventilator-associated pneumonia (VAP), which occurs in approximately 20% of mechanically ventilated patients. VAP results either from aspiration of pathogen-contaminated oropharyngeal secretions or contaminated biofilms that form on endotracheal tubes (ETTs) after intubation. VAP results in increased duration of mechanical ventilation, increased intensive care unit and hospital length of stay, increased risk of death and increased healthcare costs. Because of its impact on patient outcomes and the healthcare system, VAP is regarded as an important patient safety issue and there is an urgent need for better evidence on the efficacy of prevention strategies. Modified ETTs that reduce aspiration of oropharyngeal secretions with subglottic secretion drainage or reduce the occurrence of biofilm with a coating of ceragenins (CSAs) are available for clinical use in Canada. In this implementation study, we will evaluate the efficacy of these two types of Health Canada-licensed ETTs on the occurrence of VAP, and impact on patient-centred outcomes.

METHODS

In this ongoing, pragmatic, prospective, longitudinal, interrupted time, cross-over implementation study, we will compare the efficacy of a CSA-coated ETT (CeraShield N8 Pharma) with an ETT with subglottic secretion drainage (Taper Guard, Covidien). The study periods consist of four alternating time periods of 11 or 12 weeks or a total of 23 weeks for each ETT. All patients intubated with the study ETT in each time period will be included in an intention-to-treat analysis. Outcomes will include VAP incidence, mortality and health services utilisation including antibiotic use and length of stay.

ETHICS AND DISSEMINATION

This study has been approved by the Health Sciences Research Ethics Board at Queen's University. The results of this study will be actively disseminated through manuscript publication and conference presentations.

TRIAL REGISTRATION NUMBER

NCT05761613.

Association Between Daily Toothbrushing and Hospital-Acquired Pneumonia: A Systematic Review and Meta-Analysis

Importance

Hospital-acquired pneumonia (HAP) is the most common and morbid health care-associated infection, but limited data on effective prevention strategies are available.

Objective

To determine whether daily toothbrushing is associated with lower rates of HAP and other patient-relevant outcomes.

Data Sources

A search of PubMed, Embase, Cumulative Index to Nursing and Allied Health, Cochrane Central Register of Controlled Trials, Web of Science, Scopus, and 3 trial registries was performed from inception through March 9, 2023.

Study Selection

Randomized clinical trials of hospitalized adults comparing daily oral care with toothbrushing vs regimens without toothbrushing.

Data Extraction and Synthesis

Data extraction and risk of bias assessments were performed in duplicate. Meta-analysis was performed using random-effects models.

Main Outcomes and Measures

The primary outcome of this systematic review and meta-analysis was HAP. Secondary outcomes included hospital and intensive care unit (ICU) mortality, duration of mechanical ventilation, ICU and hospital lengths of stay, and use of antibiotics. Subgroups included patients who received invasive mechanical ventilation vs those who did not, toothbrushing twice daily vs more frequently, toothbrushing provided by dental professionals vs general nursing staff, electric vs manual toothbrushing, and studies at low vs high risk of bias.

Results

A total of 15 trials met inclusion criteria, including 10 742 patients (2033 in the ICU and 8709 in non-ICU departments; effective population size was 2786 after shrinking the population to account for 1 cluster randomized trial in non-ICU patients). Toothbrushing was associated with significantly lower risk for HAP (risk ratio [RR], 0.67 [95% CI, 0.56-0.81]) and ICU mortality (RR, 0.81 [95% CI, 0.69-0.95]). Reduction in pneumonia incidence was significant for patients receiving invasive mechanical ventilation (RR, 0.68 [95% CI, 0.57-0.82) but not for patients who were not receiving invasive mechanical ventilation (RR, 0.32 [95% CI, 0.05-2.02]). Toothbrushing for patients in the ICU was associated with fewer days of mechanical ventilation (mean difference, -1.24 [95% CI, -2.42 to -0.06] days) and a shorter ICU length of stay (mean difference, -1.78 [95% CI, -2.85 to -0.70] days). Brushing twice a day vs more frequent intervals was associated with similar effect estimates. Results were consistent in a sensitivity analysis restricted to 7 studies at low risk of bias (1367 patients). Non-ICU hospital length of stay and use of antibiotics were not associated with toothbrushing.

Conclusions

The findings of this systematic review and meta-analysis suggest that daily toothbrushing may be associated with significantly lower rates of HAP, particularly in patients receiving mechanical ventilation, lower rates of ICU mortality, shorter duration of mechanical ventilation, and shorter ICU length of stay. Policies and programs encouraging more widespread and consistent toothbrushing are warranted.

Association of mean RDW values and changes in RDW with in-hospital mortality in ventilator-associated pneumonia (VAP): Evidence from MIMIC-IV database

INTRODUCTION

Ventilator-associated pneumonia (VAP) is a hospital-acquired infection with high mortality, and remains a challenge for clinical treatment. Red blood cell distribution width (RDW) was associated with worse outcomes in several diseases. The purpose of this study was to investigate the relationship between mean RDW values, changes in RDW (delta RDW), and in-hospital mortality among patients with VAP.

METHODS

In the present study, we enrolled 1266 VAP patients from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. All patients were categorized into low group, medium group, and high group according to tertiles of mean RDW values. The primary outcome was all-cause in-hospital mortality. Univariate logistic regression analysis, multivariate logistic regression analysis, and restricted cubic spline (RCS) curve were performed to determine the association between mean RDW values and in-hospital mortality in VAP. Moreover, RCS curve was plotted to explore the dose-response relationship between delta RDW and in-hospital mortality in VAP.

RESULTS

Among the VAP patients included in the study, the in-hospital mortality was 20.85% with 264 non-survivors and 1002 survivors. The non-survivors exhibited significantly higher mean RDW values and delta RDW values compared to survivors. Multivariate logistic regression analysis indicated that mean RDW values were positively associated with in-hospital mortality in VAP after adjusting for relevant covariates. The RCS curve demonstrated a dose-response relationship between mean RDW and the mortality in VAP. Moreover, a linear relationship was observed between delta RDW and in-hospital mortality in VAP.

CONCLUSION

Higher mean RDW values were significantly associated with an increased risk of in-hospital mortality in VAP. Additionally, a linear relationship was found between delta RDW values and in-hospital mortality. These findings suggest that RDW can be used to identify high-risk patients with poorer outcomes in VAP.

Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia: A Literature Review

Hospital-acquired pneumonia (HAP) and its subtype, ventilator-associated pneumonia (VAP), remain two significant causes of morbidity and mortality worldwide, despite the better understanding of pathophysiological mechanisms, etiology, risk factors, preventive methods (bundle of care principles) and supportive care. Prior detection of the risk factors combined with a clear clinical judgement based on clinical scores and dosage of different inflammatory biomarkers (procalcitonin, soluble triggering receptor expressed on myelloid cells type 1, C-reactive protein, mid-regional pro-adrenomedullin, mid-regional pro-atrial natriuretic peptide) represent the cornerstones of a well-established management plan by improving patient's outcome. This review article provides an overview of the newly approved terminology considering nosocomial pneumonia, as well as the risk factors, biomarkers, diagnostic methods and new treatment options that can guide the management of this spectrum of infections.

A Path towards Timely VAP Diagnosis: Proof-of-Concept Study on Pyocyanin Sensing with Cu-Mg Doped Graphene Oxide

In response to the urgent requirement for rapid, precise, and cost-effective detection in intensive care units (ICUs) for ventilated patients, as well as the need to overcome the limitations of traditional detection methods, researchers have turned their attention towards advancing novel technologies. Among these, biosensors have emerged as a reliable platform for achieving accurate and early diagnoses. In this study, we explore the possibility of using Pyocyanin analysis for early detection of pathogens in ventilator-associated pneumonia (VAP) and lower respiratory tract infections in ventilated patients. To achieve this, we developed an electrochemical sensor utilizing a graphene oxide-copper oxide-doped MgO (GO - Cu - Mgo) (GCM) catalyst for Pyocyanin detection. Pyocyanin is a virulence factor in the phenazine group that is produced by Pseudomonas aeruginosa strains, leading to infections such as pneumonia, urinary tract infections, and cystic fibrosis. We additionally investigated the use of DNA aptamers for detecting Pyocyanin as a biomarker of Pseudomonas aeruginosa, a common causative agent of VAP. The results of this study indicated that electrochemical detection of Pyocyanin using a GCM catalyst shows promising potential for various applications, including clinical diagnostics and drug discovery.

GC-MS-based metabolomics of volatile organic compounds in exhaled breath: applications in health and disease. A review

Exhaled breath analysis, with particular emphasis on volatile organic compounds, represents a growing area of clinical research due to its obvious advantages over other diagnostic tests. Numerous pathologies have been extensively investigated for the identification of specific biomarkers in exhalates through metabolomics. However, the transference of breath tests to clinics remains limited, mainly due to deficiency in methodological standardization. Critical steps include the selection of breath sample types, collection devices, and enrichment techniques. GC-MS is the reference analytical technique for the analysis of volatile organic compounds in exhalates, especially during the biomarker discovery phase in metabolomics. This review comprehensively examines and compares metabolomic studies focusing on cancer, lung diseases, and infectious diseases. In addition to delving into the experimental designs reported, it also provides a critical discussion of the methodological aspects, ranging from the experimental design and sample collection to the identification of potential pathology-specific biomarkers.

[Diagnosis and antibiotic therapy of nosocomial pneumonia in adults: from recommendations to real practice. A review]

Nosocomial pneumonia is a healthcare-associated infection with significant consequences for the patient and the healthcare system. The efficacy of treatment significantly depends on the timeliness and adequacy of the antibiotic therapy regimen. The growth of resistance of gram-negative pathogens of nosocomial pneumonia to antimicrobial agents increases the risk of prescribing inadequate empirical therapy, which worsens the results of patient treatment. Identification of risk factors for infection with multidrug-resistant microorganisms, careful local microbiological monitoring with detection of resistance mechanisms, implementation of antimicrobial therapy control strategy and use of rational combinations of antibacterial drugs are of great importance. In addition, the importance of using new drugs with activity against carbapenem-resistant strains, including ceftazidime/aviabactam, must be understood. This review outlines the current data on the etiology, features of diagnosis and antibacterial therapy of nosocomial pneumonia.

Temperature management in the intensive care unit: a practical survey from China

Introduction: Temperature management is an important aspect of the treatment of critically ill patients, but there are differences in the measurement and management of temperature in different Intensive Care Units (ICUs). The objective of this study was to understand the current situation of temperature measurement and management in ICUs in China, and to provide a basis for standardized temperature management in ICUs.Methods: A 20-question survey was used to gather information on temperature management strategies from ICUs across China. Data such as method and frequency of temperature measurement, management goals, cooling measures, and temperature management recommendations were collected.Results: A total of 425 questionnaires from unique ICUs were included in the study, with responses collected from all provinces and autonomous regions in China. Mercury thermometers were the most widely used measurement tool (82.39%) and the axilla was the most common measurement site (96.47%). There was considerable variability in the frequency of temperature measurement, the temperature at which intervention should begin, intervention duration, and temperature management goals. While there was no clearly preferred drug-based cooling method, the most widely used equipment-based cooling method was the ice blanket machine (93.18%). The most frequent recommendations for promoting temperature management were continuous monitoring and targeted management.Conclusion: Our investigation revealed a high level of variability in the methods of temperature measurement and management among ICUs in China. Since fever is a common clinical symptom in critically ill patients and can lead to prolonged ICU stays, we propose that standardized guidelines are urgently needed for the management of body temperature (BT) in these patients.

Healthcare providers consistently overestimate the diagnostic probability of ventilator-associated pneumonia

OBJECTIVE

To assess the accuracy of provider estimates of ventilator-associated pneumonia (VAP) diagnostic probability in various clinical scenarios.

DESIGN

We conducted a clinical vignette-based survey of intensive care unit (ICU) physicians to evaluate provider estimates of VAP diagnostic probability before and after isolated cardinal VAP clinical changes and VAP diagnostic test results. Responses were used to calculate imputed diagnostic likelihood ratios (LRs), which were compared to evidence-based LRs.

SETTING

Michigan Medicine University Hospital, a tertiary-care center.

PARTICIPANTS

This study included 133 ICU clinical faculty and house staff.

RESULTS

Provider estimates of VAP diagnostic probability were consistently higher than evidence-based diagnostic probabilities. Similarly, imputed LRs from provider-estimated diagnostic probabilities were consistently higher than evidence-based LRs. These differences were most notable for positive bronchoalveolar lavage culture (provider-estimated LR 5.7 vs evidence-based LR 1.4; P < .01), chest radiograph with air bronchogram (provider-estimated LR 6.0 vs evidence-based LR 3.6; P < .01), and isolated purulent endotracheal secretions (provider-estimated LR 1.6 vs evidence-based LR 0.8; P < .01). Attending physicians and infectious disease physicians were more accurate in their LR estimates than trainees (P = .04) and non-ID physicians (P = .03).

CONCLUSIONS

Physicians routinely overestimated the diagnostic probability of VAP as well as the positive LRs of isolated cardinal VAP clinical changes and VAP diagnostic test results. Diagnostic stewardship initiatives, including educational outreach and clinical decision support systems, may be useful adjuncts in minimizing VAP overdiagnosis and ICU antibiotic overuse.

Comparing the Accuracy of Mini-BAL to Bronchoscopic BAL in the Diagnosis of Pneumonia Among Ventilated Patients: A Systematic Literature Review

Background: Despite its widespread use, there are no direct studies comparing mini-bronchoalveolar lavage (mini-BAL) to bronchoscopic bronchoalveolar lavage (BAL) for diagnosing pneumonia in ventilated patients. The aim of this study was to perform a systematic review of studies comparing ventilated patients undergoing both bronchoscopic BAL and mini-BAL, to determine the mini-BAL's diagnostic accuracy. Methods: We conducted a systematic review searching the databases PubMed (MEDLINE), EMBASE, Cochrane Library, Scopus, and clinicaltrials.gov from inception until January 2022, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search terms included variations on "pneumonia," "critical illness," and "mini-bronchoalveolar lavage." Article screening and data extraction were performed independently by 2 reviewers. Results: Our search yielded 4296 abstracts. This was narrowed to 6 studies in which each patient underwent both mini-BAL and bronchoscopic BAL in succession. Included patients had a mean APACHE II score of 20.02 ± 3.81 and 15.95 ± 11.46 ventilator days. The sensitivity of the mini-BAL for diagnosis of pneumonia was 0.90 (95% confidence interval [CI]: 0.778-1.000) and the specificity was 0.827 (95% CI: 0.716-0.938). Limitations included inconsistency in volume of saline instilled and heterogeneity in included patients Conclusion: This study is the first to compile data from multiple publications directly comparing the mini-BAL to bronchoscopic BAL for diagnosing pneumonia in ventilated patients. Our data demonstrate a high degree of both sensitivity and specificity of mini-BAL for the diagnosis of pneumonia in ventilated patients and indicate that mini-BAL could be considered as an acceptable alternative diagnostic study.

Nonbronchoscopic Bronchoalveolar Lavage Improves Respiratory Culture Accuracy in Critically Ill Patients

OBJECTIVES

Diagnosis of pneumonia is challenging in critically ill, intubated patients due to limited diagnostic modalities. Endotracheal aspirate (EA) cultures are standard of care in many ICUs; however, frequent EA contamination leads to unnecessary antibiotic use. Nonbronchoscopic bronchoalveolar lavage (NBBL) obtains sterile, alveolar cultures, avoiding contamination. However, paired NBBL and EA sampling in the setting of a lack of gold standard for airway culture is a novel approach to improve culture accuracy and limit antibiotic use in the critically ill patients.

DESIGN

We designed a pilot study to test respiratory culture accuracy between EA and NBBL. Adult, intubated patients with suspected pneumonia received concurrent EA and NBBL cultures by registered respiratory therapists. Respiratory culture microbiology, cell counts, and antibiotic prescribing practices were examined.

SETTING

We performed a prospective pilot study at the Cleveland Clinic Main Campus Medical ICU in Cleveland, Ohio for 22 months from May 2021 through March 2023.

PATIENTS OR SUBJECTS

Three hundred forty mechanically ventilated patients with suspected pneumonia were screened. Two hundred fifty-seven patients were excluded for severe hypoxia (Fio2 ≥ 80% or positive end-expiratory pressure ≥ 12 cm H2O), coagulopathy, platelets less than 50,000, hemodynamic instability as determined by the treating team, and COVID-19 infection to prevent aerosolization of the virus.

INTERVENTIONS

All 83 eligible patients were enrolled and underwent concurrent EA and NBBL.

MEASUREMENTS AND MAIN RESULTS

More EA cultures (42.17%) were positive than concurrent NBBL cultures (26.51%, p = 0.049), indicating EA contamination. The odds of EA contamination increased by eight-fold 24 hours after intubation. EA was also more likely to be contaminated with oral flora when compared with NBBL cultures. There was a trend toward decreased antibiotic use in patients with positive EA cultures if paired with a negative NBBL culture. Alveolar immune cell populations were recovered from NBBL samples, indicating successful alveolar sampling. There were no major complications from NBBL.

CONCLUSIONS

NBBL is more accurate than EA for respiratory cultures in critically ill, intubated patients. NBBL provides a safe and effective technique to sample the alveolar space for both clinical and research purposes.

Society of Critical Care Medicine and the Infectious Diseases Society of America Guidelines for Evaluating New Fever in Adult Patients in the ICU

RATIONALE

Fever is frequently an early indicator of infection and often requires rigorous diagnostic evaluation.

OBJECTIVES

This is an update of the 2008 Infectious Diseases Society of America and Society (IDSA) and Society of Critical Care Medicine (SCCM) guideline for the evaluation of new-onset fever in adult ICU patients without severe immunocompromise, now using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology.

PANEL DESIGN

The SCCM and IDSA convened a taskforce to update the 2008 version of the guideline for the evaluation of new fever in critically ill adult patients, which included expert clinicians as well as methodologists from the Guidelines in Intensive Care, Development and Evaluation Group. The guidelines committee consisted of 12 experts in critical care, infectious diseases, clinical microbiology, organ transplantation, public health, clinical research, and health policy and administration. All task force members followed all conflict-of-interest procedures as documented in the American College of Critical Care Medicine/SCCM Standard Operating Procedures Manual and the IDSA. There was no industry input or funding to produce this guideline.

METHODS

We conducted a systematic review for each population, intervention, comparison, and outcomes question to identify the best available evidence, statistically summarized the evidence, and then assessed the quality of evidence using the GRADE approach. We used the evidence-to-decision framework to formulate recommendations as strong or weak or as best-practice statements.

RESULTS

The panel issued 12 recommendations and 9 best practice statements. The panel recommended using central temperature monitoring methods, including thermistors for pulmonary artery catheters, bladder catheters, or esophageal balloon thermistors when these devices are in place or accurate temperature measurements are critical for diagnosis and management. For patients without these devices in place, oral or rectal temperatures over other temperature measurement methods that are less reliable such as axillary or tympanic membrane temperatures, noninvasive temporal artery thermometers, or chemical dot thermometers were recommended. Imaging studies including ultrasonography were recommended in addition to microbiological evaluation using rapid diagnostic testing strategies. Biomarkers were recommended to assist in guiding the discontinuation of antimicrobial therapy. All recommendations issued were weak based on the quality of data.

CONCLUSIONS

The guidelines panel was able to formulate several recommendations for the evaluation of new fever in a critically ill adult patient, acknowledging that most recommendations were based on weak evidence. This highlights the need for the rapid advancement of research in all aspects of this issue-including better noninvasive methods to measure core body temperature, the use of diagnostic imaging, advances in microbiology including molecular testing, and the use of biomarkers.

Evaluation of the Kinetics of Pancreatic Stone Protein as a Predictor of Ventilator-Associated Pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) is a severe condition. Early and adequate antibiotic treatment is the most important strategy for improving prognosis. Pancreatic Stone Protein (PSP) has been described as a biomarker that increases values 3-4 days before the clinical diagnosis of nosocomial sepsis in different clinical settings. We hypothesized that serial measures of PSP and its kinetics allow for an early diagnosis of VAP.

METHODS

The BioVAP study was a prospective observational study designed to evaluate the role of biomarker dynamics in the diagnosis of VAP. To determine the association between repeatedly measured PSP and the risk of VAP, we used joint models for longitudinal and time-to-event data.

RESULTS

Of 209 patients, 43 (20.6%) patients developed VAP, with a median time of 4 days. Multivariate joint models with PSP, CRP, and PCT did not show an association between biomarkers and VAP for the daily absolute value, with a hazard ratio (HR) for PSP of 1.01 (95% credible interval: 0.97 to 1.05), for CRP of 1.00 (0.83 to 1.22), and for PCT of 0.95 (0.82 to 1.08). The daily change of biomarkers provided similar results, with an HR for PSP of 1.15 (0.94 to 1.41), for CRP of 0.76 (0.35 to 1.58), and for PCT of 0.77 (0.40 to 1.45).

CONCLUSION

Neither absolute PSP values nor PSP kinetics alone nor in combination with other biomarkers were useful in improving the prediction diagnosis accuracy in patients with VAP.

CLINICAL TRIAL REGISTRATION

Registered retrospectively on August 3rd, 2012. NCT02078999.

Incidence, microbiological and immunological characteristics of ventilator-associated pneumonia assessed by bronchoalveolar lavage and endotracheal aspirate in a prospective cohort of COVID-19 patients: CoV-AP study

BACKGROUND

No 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.

METHODS

Prospective 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.

RESULTS

Seventy-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).

CONCLUSIONS

In 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 REGISTRATION

NCT04766983, registered on February 23, 2021.

Effectiveness of supervised implementation of an oral health care protocol on ventilator-associated pneumonia patients in intensive care units: a double-blind multicenter randomized controlled trial

Background

The available scientific evidence suggests a significant association between oral bacteria and the incidence of ventilator-associated pneumonia (VAP).

Aims

The aim of this study was to determine the effectiveness of an oral health protocol in the prevention of ventilator-associated pneumonia.

Methods

In this multi-center RCT, conducted in the intensive care units of neurological patients in three general teaching hospitals of two provinces located in the west of the Iran, a consecutive sample of 200 intubated patients were initially recruited. Patients were randomly allocated to the intervention (received oral health care based on evidence-based oral health protocol) or control (routine oral health care) groups. Both groups received their prescribed treatment regimen for seven consecutive days. The percentage of VAP diagnoses as main outcome assessed using clinical pulmonary infection score (CPIS).

Findings

The rate of VAP in the intervention and control groups was 5% and 64%, respectively. The intervention reduced the risk of VAP by 97% and this difference was statistically significant (P <0.001). The chance of VAP occurrence in patients with lower levels of consciousness in univariate and multivariate analysis was significantly higher (OR: 2.38; 95%CI: 1.11-5.26) P <0.05).

Conclusion

The results of our study suggest that the use of a dynamic supervised oral health care guideline is more effective than the routinely used protocols in the intensive care units of hospitals.

Influence of oral comprehensive nursing intervention on mechanically ventilated patients in ICU: a randimized controlled study

OBJECTIVE

To explore the effect of oral comprehensive nursing intervention on mechanically ventilated patients in ICU.

METHODS

Select 76 cases of mechanically ventilated patients in severe ICU admitted to our hospital from January 2022 to October 2022 as the research objects, and divide them into the control group and the observation group according to the way the patients receive oral care. 38 cases each. The patients in the control group received routine nursing intervention, and the patients in the observation group received comprehensive oral nursing intervention on the basis of the nursing of the control group. The clinical index data, oropharyngeal hygiene, pH value, blood gas analysis index levels, and the occurrence and death of ventilator-associated pneumonia were compared between the two groups of patients.

RESULTS

The hospitalization time of the two groups was compared (P > 0.05); the mechanical ventilation time and ICU stay time of the observation group were significantly lower than those of the control group (all, P < 0.05); the oral odor scores, The plaque index and soft scale index were significantly lower than those of the control group (all, P < 0.05); the pH value, PaO 2 value, and SpO 2 value of the observation group were significantly lower than those of the control group, and the PaCO 2 value was significantly higher than that of the control group. group (all, P < 0.05); the incidence of VAP in the control group was 55.26%, and the mortality rate was 15.79%, the incidence rate of VAP in the observation group was 21.05%, and the mortality rate was 2.63%, and the incidence rate and mortality rate of VAP in the observation group were significantly lower in the control group (all, P < 0.05).

CONCLUSION

The application of nursing intervention can effectively promote the recovery of patients, improve the hygiene of patients' oropharynx, adjust the levels of pH and blood gas-related indicators in patients, and reduce VAP in patients. risk of morbidity and mortality.

Comparison of the clinical efficacy and toxicity of nebulized polymyxin monotherapy and combined intravenous and nebulized polymyxin for the treatment of ventilator-associated pneumonia caused by carbapenem-resistant gram-negative bacteria: a retrospective cohort study

Objective: To investigate the clinical efficacy and toxicity of nebulized polymyxin monotherapy and combined intravenous and nebulized polymyxin for the treatment of VAP caused by CR-GNB. Additionally, among patients treated with nebulized polymyxin monotherapy, we compared the clinical efficacy and toxicity of polymyxin B and polymyxin E. Methods: This study was a single-center, retrospective study. Included patients received aerosolized polymyxin for at least 72 h with or without intravenous polymyxin for the management of CR-GNB VAP. The primary endpoint was clinical cure at the end of polymyxin therapy. Secondary endpoints included AKI incidence, time of bacteria-negative conversion, duration of MV after inclusion, length of stay in ICU, and all-cause ICU mortality. Results: 39 patients treated with nebulized polymyxin monotherapy were assigned to the NL-polymyxin group. 39 patients treated with nebulized polymyxin combined with intravenous use of polymyxin were assigned to the IV-NL-polymyxin group. Among the NL-polymyxin group, 19 patients were treated with polymyxin B and 20 with polymyxin E. The clinical baseline characteristics before admission to the ICU and before nebulization of polymyxin were similar between the two groups. No differences were found between the two study groups in terms of microorganism distribution, VAP cure rate, time of bacteria-negative conversion, duration of MV after inclusion, length of stay in ICU and all-cause ICU mortality. Similarly, survival analysis did not differ between the two groups (χ2 = 3.539, p = 0.06). AKI incidence was higher in the IV-NL-polymyxin group. When comparing the clinical efficacy and toxicity to polymyxin B and polymyxin E, there was no difference between the two groups in terms of VAP cure rate, time of bacteria-negative conversion, duration of MV after inclusion, length of stay in ICU, SOFA score, CPIS, AKI incidence and all-cause ICU mortality. Conclusion: Our study found that nebulized polymyxin monotherapy was non-inferior to combination therapy with intravenous polymyxin in treating CR-GNB-VAP. Furthermore, we observed no differences in clinical efficacy or related toxic side effects between polymyxin B and polymyxin E during nebulized polymyxin therapy as monotherapy. However, future prospective studies with larger sample sizes are required to confirm these findings.

Prevalence and Clinical Characteristics of Bacterial Pneumonia in Neurosurgical Emergency Center Patients: A Retrospective Study Spanning 13 Years at a Tertiary Center

Patients with brain injuries are at a heightened susceptibility to bacterial pneumonia, and the timely initiation of empiric antibiotic treatment has been shown to substantially reduce mortality rates. Nevertheless, there is a need for knowledge regarding the resistance and prevalence of pulmonary bacterial infections in this patient population. To address this gap, a retrospective study was conducted at a neurosurgical emergency center, focusing on patients with brain injuries. Among the entire patient population, a total of 739 individuals (18.23%) were identified as having bacterial pneumonia, consisting of 1489 strains of Gram-negative bacteria and 205 strains of Gram-positive bacteria. The resistance of Klebsiella pneumoniae to imipenem exhibited a significant increase, rising from 21.74% in 2009 to 96.67% in 2018, and subsequently reaching 48.47% in 2021. Acinetobacter baumannii displayed resistance rates exceeding 80.0% against multiple antibiotics. The resistance profile of Pseudomonas aeruginosa was relatively low. The proportion of Staphylococcus aureus reached its peak at 18.70% in 2016, but experienced a decline to 7.83% in 2021. The abundance of Gram-negative bacteria exceeded that of Gram-positive bacteria by a factor of 5.96. Klebsiella pneumoniae, Acinetobacter baumannii, and Staphylococcus aureus are prominent pathogens characterized by limited antibiotic choices and scarce treatment alternatives for the isolated strains.

Pulmonary Co-Infections Detected Premortem Underestimate Postmortem Findings in a COVID-19 Autopsy Case Series

Bacterial and fungal co-infections are reported complications of coronavirus disease 2019 (COVID-19) in critically ill patients but may go unrecognized premortem due to diagnostic limitations. We compared the premortem with the postmortem detection of pulmonary co-infections in 55 fatal COVID-19 cases from March 2020 to March 2021. The concordance in the premortem versus the postmortem diagnoses and the pathogen identification were evaluated. Premortem pulmonary co-infections were extracted from medical charts while applying standard diagnostic definitions. Postmortem co-infection was defined by compatible lung histopathology with or without the detection of an organism in tissue by bacterial or fungal staining, or polymerase chain reaction (PCR) with broad-range bacterial and fungal primers. Pulmonary co-infection was detected premortem in significantly fewer cases (15/55, 27%) than were detected postmortem (36/55, 65%; p < 0.0001). Among cases in which co-infection was detected postmortem by histopathology, an organism was identified in 27/36 (75%) of cases. Pseudomonas, Enterobacterales, and Staphylococcus aureus were the most frequently identified bacteria both premortem and postmortem. Invasive pulmonary fungal infection was detected in five cases postmortem, but in no cases premortem. According to the univariate analyses, the patients with undiagnosed pulmonary co-infection had significantly shorter hospital (p = 0.0012) and intensive care unit (p = 0.0006) stays and significantly fewer extra-pulmonary infections (p = 0.0021). Bacterial and fungal pulmonary co-infection are under-recognized complications in critically ill patients with COVID-19.

Exploring the complex relationship between the lung microbiome and ventilator-associated pneumonia

INTRODUCTION

Understanding the presence and function of a diverse lung microbiome in acute lung infections, particularly ventilator-associated pneumonia (VAP), is still limited, evidencing significant gaps in our knowledge.

AREAS COVERED

In this comprehensive narrative review, we aim to elucidate the contribution of the respiratory microbiome in the development of VAP by examining the current knowledge on the interactions among microorganisms. By exploring these intricate connections, we endeavor to enhance our understanding of the disease's pathophysiology and pave the way for novel ideas and interventions in studying the respiratory tract microbiome.

EXPERT OPINION

The conventional perception of lungs as sterile is deprecated since it is currently recognized the existence of a diverse microbial community within them. However, despite extensive research on the role of the respiratory microbiome in healthy lungs, respiratory chronic diseases and acute lung infections such as pneumonia are not fully understood. It is crucial to investigate further the relationship between the pathophysiology of VAP and the pulmonary microbiome, elucidating the mechanisms underlying the interactions between the microbiome, host immune response and mechanical ventilation for the development of VAP.

Aerosolized Plus Intravenous Polymyxin B Versus Colistin in the Treatment of Pandrug-Resistant Klebsiella Pneumonia-mediated Ventilator-Associated Pneumonia: A Retrospective Cohort Study in Bangladesh

Background

Pandrug-resistant Klebsiella pneumoniae ventilator associated pneumonia (VAP) is associated with high rate of mortality in intensive care unit (ICU) and has been recognized as a difficult-to-treat infection worldwide. Polymyxin B or colistin-based combination therapies are frequently used worldwide though microbial eradication rate is not promising.

Aim

The aim of this study is to compare the clinical outcome of intravenous with aerosolized polymyxin B versus colistin in the treatment of pandrug-resistant K. pneumoniae VAP.

Methods

This retrospective cohort study was conducted on 222 mechanically ventilated patients admitted from May 11, 2019 to October 19, 2020. K. pneumoniae isolates were resistant to all available antibiotics, including polymyxins in culture sensitivity tests. As treatment, polymyxin B and colistin was administered in intravenous and aerosolized form concurrently twice daily in 106 patients and 116 patients in PMB and CLN group, respectively for 14 days. Survival rate, safety, and clinical outcomes were compared among the groups. The Cox proportional-hazard model was performed to calculate hazard ratio (HR) with 95% confidence intervals (CI).

Results

Patients in PMB group showed more microbial eradication than the patients CLN group [68.1% (n=116)/83% (n=106), respectively; P <0.05). The median day of intubation and ICU stay in PMB group was shorter than that in CLN group [10 (IQR: 9-12.25) vs. 14 (IQR: 11-19), P <0.05; 12 (IQR: 10-14) vs. 15 (IQR: 9-18.5), P=0.072, respectively] with reduced 60-day all-cause mortality rate [15% (n=106) vs. 21.55% (n=116)]. Polymyxin B improved survival compared to colistin (multivariate HR: 0.662; 95% CI=0.359-1.222, P=0.195).

Conclusions

Concurrent administration of intravenous and aerosolized polymyxin B in patients with pandrug-resistant K. pneumoniae-associated VAP revealed better microbial eradication, reduced the length of intubation and ICU stay, and improved survival rate compared to colistin.

Efficacy of an Herbal Preparation (Atomy's HemoHIM®) against Ventilator-associated Pneumonia: A Randomized Controlled Clinical Trial

Objective

Despite the standard guideline recommendations to prevent ventilator-associated pneumonia (VAP), it has remained one of the common lung infections in the intensive care unit (ICU). This clinical trial was designed to evaluate the effect of HemoHIM®, a mixture of traditional Korean medicinal plants, on preventing VAP in ICU patients.

Methods

This randomized controlled clinical trial was conducted on mechanically ventilated adult ICU patients with a clinical pulmonary infection score of VAP ≤6 in the first 48 h of ventilation. Patients in the intervention group received a packet of HemoHIM daily and orally for 7 days in addition to standard prevention strategies. However, in the control group, only standard prevention strategies were carried out. All patients were followed daily for VAP incidence for 14 days.

Findings

The overall VAP incidence was 36.4 and 57.4 episodes per 1000 days of mechanical ventilation in the intervention and control groups, respectively (P = 0.041; odds ratio = 0.26; 95% confidence interval = 0.070-0.944). The median length of mechanical ventilation during study follow-up was significantly lower in the intervention than in the control group (P = 0.033). The number of pneumonia-free days during the study was considerably higher in the intervention group (P value of the log-rank test = 0.023).

Conclusion

According to the results of this study, the HemoHIM herbal supplement had beneficial effects in preventing the occurrence of VAP and significantly reduced the incidence of pneumonia in the intervention group. Further comprehensive research is required to draw more accurate conclusions.

Effect of clove mouthwash on the incidence of ventilator-associated pneumonia in intensive care unit patients: a comparative randomized triple-blind clinical trial

OBJECTIVES

Ventilator-associated pneumonia (VAP) is one of the most common nosocomial infections in intensive care units (ICUs), and the use of mouthwash is the most widely used method to prevent its incidence. The aim of this study was to investigate effect of clove mouthwash on the incidence of VAP in the ICU.

MATERIALS AND METHODS

This comparative, randomized, triple-blind, clinical trial was conducted on 168 eligible ICU patients at Kosar Hospital in Semnan, Iran, during 2021-2022, who were divided into intervention and control groups using random blocks. The intervention group received clove extract mouthwash at 6.66% concentration, and the control group received chlorhexidine 0.2% twice a day for 5 days (routine care). Data were collected using a demographic questionnaire, and disease severity was measured based on the Acute Physiology and Chronic Health Evaluation II (APACHE II) score, oral health status was examined using the Beck Oral Assessment Scale (BOAS), and VAP diagnosis was made based on the Modified Clinical Pulmonary Infection Score (MCPIS).

RESULTS

Before the intervention, there was no significant difference in disease severity (p = 0.412) and oral health status (p = 0.239) between the patients in the two groups. After the intervention, 20.2% of the patients in the intervention group and 41.7% of those in the control group acquired VAP. The risk of VAP was 2.06 times higher in the control group than in the intervention group (p = 0.005, 95% CI: 1.26-3.37, RR = 2.06), but the severity of VAP did not differ significantly between the patients in the two groups (p = 0.557).

CONCLUSION

The findings showed that clove mouthwash reduces the incidence of VAP significantly.

CLINICAL RELEVANCE

Clove mouthwash can be used as a simple and low-cost method to prevent VAP in ICU patients.

Definitions, rates and associated mortality of ICU-acquired pneumonia: A multicenter cohort study

INTRODUCTION

We aimed to analyze intensive care unit (ICU)-acquired pneumonia according to 7 definitions, estimating associated hospital mortality.

METHODS

This cohort study was nested within an international randomized trial, evaluating the effect of probiotics on ICU-acquired pneumonia in 2650 mechanically ventilated adults. Each clinically suspected pneumonia was adjudicated by two physicians blinded to allocation and center. The primary outcome was ventilator-associated pneumonia (VAP) informed by ventilation for ≥2 days, new, progressive or persistent infiltrate plus 2 of: temperature > 38 °C or < 36 °C; leukopenia (<3 × 10(Fernando et al., 2020⁶⁾/L) or leukocytosis (>10 × 10(Fernando et al., 2020⁶⁾/L); and purulent sputum. We also used 6 other definitions estimating the risk of hospital mortality.

RESULTS

The frequency of ICU-acquired pneumonia varied by definition: the trial primary outcome VAP (21.6%), Clinical Pulmonary Infection Score (CPIS) (24.9%), American College Chest Physicians (ACCP) (25.0%), International Sepsis Forum (ISF) (24.4%), Reducing Oxidative Stress Study (REDOXS) (17.6%), Centers for Disease Control (CDC) (7.8%), and invasively microbiologically confirmed (1.9%). The trial primary outcome VAP (HR 1.31 [1.08, 1.60]), ISF (HR 1.32 [1.09,1.60]), CPIS (HR 1.30 [1.08,1.58]) and ACCP definitions (HR 1.22 [1.00,1.47]) were associated with hospital mortality.

CONCLUSIONS

Rates of ICU-acquired pneumonia vary by definition and are associated with differential increased risk of death.

Less Is More? Antibiotic Treatment Duration in Pseudomonas aeruginosa Ventilator-Associated Pneumonia

Recommended antimicrobial treatment durations for ventilator-associated pneumonia (VAP) caused by Pseudomonas aeruginosa have evolved over the past few decades. In this Viewpoint, we provide a narrative review of landmark trials investigating antimicrobial treatment durations for VAP caused by P. aeruginosa, and appraise iterations of expert consensus guidelines based on these data. We highlight strengths and weaknesses of existing data on this topic and provide recommendations for future avenues of study.

Pathogen characteristics, changes in inflammation levels, and risk factors for ventilator-associated pneumonia in elderly patients with gastric cancer after surgery

BACKGROUND

Ventilator-associated pneumonia is a common complication in mechanically ventilated patients. Elderly patients with gastric cancer have decreased physical skills and become susceptible to ventilator-associated pneumonia, causing adverse effects, and understanding of the composition of pathogenic bacteria, inflammation level, and risk factors for such patients can provide a basis for disease prevention, diagnosis, and treatment. It is conjectured that Gram-negative bacteria are the main pathogens of postoperative ventilator-associated pneumonia in elderly gastric cancer patients, and they are associated with procalcitonin (PCT), interleukin-8 (IL-8), and high mobility group box 1 protein (HMGB1) as the influencing factors of infection.

AIM

To explore the etiological characteristics, changes in inflammation levels, and risk factors for ventilator-associated pneumonia in elderly patients after surgery for gastric cancer.

METHODS

Fifty-two patients with ventilator-associated pneumonia after gastric cancer surgery at our hospital from August 2017 to August 2021 were selected as a study group, and 78 patients without ventilator-associated pneumonia after surgery in the same period were selected as a control group. The distribution characteristics of pathogenic bacteria and serum inflammatory indexes (PCT, IL-8, and HMGB1) in the study group, control group, and patients with different types of infections in the study group were analyzed. The risk factors associated with ventilator-associated pneumonia in elderly patients with gastric cancer after surgery were identified by Logistic regression analysis.

RESULTS

The percentages of patients who were older than 70 years, underwent mechanical ventilation for more than 5 d, used more than two types of antibiotics, and had a serum albumin level ≤ 30 g/L, basic lung disease, and smoking history, as well as serum PCT, IL-8, and HMGB1 levels were significantly higher in the study group than in the control group (P < 0.05). Logistic regression analysis showed that age > 70 years, mechanical ventilation time > 5 d, serum albumin level ≤ 30 g/L, underlying lung disease, PCT level > 1.0 μg/L, IL-8 level > 15.5 ng/L, and HMGB1 level > 60.0 pg/mL were risk factors for ventilator-associated pneumonia in elderly patients after gastric cancer surgery (P < 0.05). A total of 82 strains of pathogenic bacteria were isolated from 52 patients in the study group. The main strains were Gram-negative bacteria (54 strains, 65.85%). Serum PCT, IL-8, and HMGB1 levels in patients infected with Gram-negative bacteria in the study group were significantly higher than those of patients infected with Gram-positive bacteria and patients with fungal infections, and in patients infected with Gram-positive bacteria than in those with fungal infections (P < 0.05).

CONCLUSION

The pathogens of ventilator-associated pneumonia in elderly patients after gastric cancer surgery are mainly Gram-negative bacteria. Serum PCT, IL-8, and HMGB1 levels can be significantly increased after infection, and their levels are related to the type of pathogens and are important risk factors for ventilator-associated pneumonia.

Ultra-Short-Course Antibiotics for Suspected Pneumonia With Preserved Oxygenation

BACKGROUND

Suspected pneumonia is the most common indication for antibiotics in hospitalized patients but is frequently overdiagnosed. We explored whether normal oxygenation could be used as an indicator to support early discontinuation of antibiotics.

METHODS

We retrospectively identified all patients started on antibiotics for pneumonia in 4 hospitals with oxygen saturations ≥95% on ambient air, May 2017-February 2021. We propensity-matched patients treated 1-2 days vs 5-8 days and compared hospital mortality and time to discharge using subdistribution hazard ratios (SHRs). Secondary outcomes included readmissions, 30-day mortality, Clostridioides difficile infections, hospital-free days, and antibiotic-free days.

RESULTS

Among 39 752 patients treated for possible pneumonia, 10 012 had median oxygen saturations ≥95% without supplemental oxygen. Of these, 2871 were treated 1-2 days and 2891 for 5-8 days; 4478 patients were propensity-matched. Patients treated 1-2 vs 5-8 days had similar hospital mortality (2.1% vs 2.8%; SHR, 0.75 [95% confidence interval {CI}, .51-1.09]) but less time to discharge (6.1 vs 6.6 days; SHR, 1.13 [95% CI, 1.07-1.19]) and more 30-day hospital-free days (23.1 vs 22.7; mean difference, 0.44 [95% CI, .09-.78]). There were no significant differences in 30-day readmissions (16.0% vs 15.8%; odds ratio [OR], 1.01 [95% CI, .86-1.19]), 30-day mortality (4.6% vs 5.1%; OR, 0.91 [95% CI, .69-1.19]), or 90-day C. difficile infections (1.3% vs 0.8%; OR, 1.67 [95% CI, .94-2.99]).

CONCLUSIONS

One-quarter of hospitalized patients treated for pneumonia had oxygenation saturations ≥95% on ambient air. Outcomes were similar with 1-2 vs 5-8 days of antibiotics. Normal oxygenation levels may help identify candidates for early antibiotic discontinuation. Prospective trials are warranted.

Trial of antibiotic restraint in presumed pneumonia: A Surgical Infection Society multicenter pilot

BACKGROUND

Pneumonia is the most common intensive care unit-acquired infection in the trauma and emergency general surgery population. Despite guidelines urging rapid antibiotic use, data supporting immediate antibiotic initiation in cases of suspected infection are limited. Our hypothesis was that a protocol of specimen-initiated antibiotic initiation would have similar compliance and outcomes to an immediate initiation protocol.

METHODS

We devised a pragmatic cluster-randomized crossover pilot trial. Four surgical and trauma intensive care units were randomized to either an immediate initiation or specimen-initiated antibiotic protocol for intubated patients with suspected pneumonia and bronchoscopically obtained cultures who did not require vasopressors. In the immediate initiation arm, antibiotics were started immediately after the culture regardless of patient status. In the specimen-initiated arm, antibiotics were delayed until objective Gram stain or culture results suggested infection. Each site participated in both arms after a washout period and crossover. Outcomes were protocol compliance, all-cause 30-day mortality, and ventilator-free alive days at 30 days. Standard statistical techniques were applied.

RESULTS

A total of 186 patients had 244 total cultures, of which only the first was analyzed. Ninety-three patients (50%) were enrolled in each arm, and 94.6% were trauma patients (84.4% blunt trauma). The median age was 50.5 years, and 21% of the cohort was female. There were no differences in demographics, comorbidities, sequential organ failure assessment, Acute Physiology and Chronic Health Evaluation II, or Injury Severity Scores. Antibiotics were started significantly later in the specimen-initiated arm (0 vs. 9.3 hours; p < 0.0001) with 19.4% avoiding antibiotics completely for that episode. There were no differences in the rate of protocol adherence, 30-day mortality, or ventilator-free alive days at 30 days.

CONCLUSION

In this cluster-randomized crossover trial, we found similar compliance rates between immediate and specimen-initiated antibiotic strategies. Specimen-initiated antibiotic protocol in patients with a suspected hospital-acquired pneumonia did not result in worse clinical outcomes compared with immediate initiation.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level II.

Early pneumonia diagnosis decreases ventilator-associated pneumonia rates in trauma population

BACKGROUND

Ventilator-associated pneumonia (VAP) is a source of morbidity and mortality for trauma patients. Aspiration events are also common because of traumatic brain injury, altered mental status, or facial trauma. In patients requiring mechanical ventilation, early pneumonias (EPs) may be erroneously classified as ventilator associated.

METHODS

A prospective early bronchoscopy protocol was implemented from January 2020 to January 2022. Trauma patients intubated before arrival or within 48 hours of admission underwent bronchoalveolar lavage (BAL) within 24 hours of intubation. Patients with more than 100,000 colony-forming units on BAL were considered to have EP.

RESULTS

A total of 117 patients underwent early BAL. Ninety-three (79.5%) had some growth on BAL with 36 (30.8%) meeting criteria for EP. For the total study population, 29 patients (24.8%) were diagnosed with VAP later in their hospital course, 12 of which had previously been diagnosed with EP. Of EP patients (n = 36), 21 (58.3%) were treated with antibiotics based on clinical signs of infection. Of EP patients who had a later pneumonia diagnosed by BAL (n = 12), seven (58.3%) grew the same organism from their initial BAL. When these patients were excluded from VAP calculation, the rate was reduced by 27.6%. Patients with EP had a higher rate of smoking history (41.7% vs. 19.8%, p < 0.001) compared with patients without EP. There was no difference in median hospital length of stay, intensive care unit length of stay, ventilator days, or mortality between the two cohorts.

CONCLUSION

Early pneumonia is common in trauma patients intubated within the first 48 hours of admission and screening with early BAL identifies patients with aspiration or pretraumatic indicators of pneumonia. Accounting for these patients with early BAL significantly reduces reported VAP rates.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level IV.

The effectiveness of colistin/levofloxacin compared to colistin/meropenem in the treatment of ventilator-associated pneumonia (VAP) caused by carbapenem-resistant Acinetobacter baumannii: a randomized controlled clinical trial

Background and purpose

The treatment of ventilator-associated pneumonia (VAP) caused by carbapenem-resistant Acinetobacter baumannii (CRAB) is still a great challenge. This study evaluated the effectiveness of the colistin/levofloxacin regimen compared to the usual colistin/meropenem regimen in the treatment of patients with VAP caused by CRAB.

Experimental approach

The patients with VAP were randomly assigned to experimental (n = 26) and control (n = 29) groups. The first group received IV colistin 4.5 MIU every 12 h + levofloxacin 750 mg IV daily, and the second group received IV colistin with the same dose + meropenem 1 g IV every 8 h for 10 days. The clinical (complete response, partial response, or treatment failure) and microbiological responses at the end of the intervention were recorded and compared between the two groups.

Findings/Results

The complete response rate was higher (n = 7; 35%) and the failure rate was lower (n = 4; 20%) in the experimental group than in the control group (n = 2; 8%, and n = 11; 44%, respectively), but the differences were not statistically significant. Even though the microbiological response rate was higher in the experimental group (n = 14; 70%) than in the control group (n = 12; 48%), the difference was not statistically significant. The mortality rate was 6 (23.10%) and 4 patients (13.8%) in the experimental and control groups, respectively (P = 0.490).

Conclusion and implication

The levofloxacin/colistin combination can be considered an alternative regimen to meropenem/colistin in the treatment of VAP caused by CRAB.

Thoracic ultrasound alone or in combination with tracheal amylase as a tool predictor of ventilator-associated pneumonia in neurocritical patients

In this study, we aim to evaluate whether thoracic ultrasound (TUS) and tracheal amylase (TA) alone or in combination can predict the development of ventilator-associated pneumonia (VAP) in neurocritical patients. Consecutive adult patients with neurocritical disease with normal chest radiographs who required intensive care unit admission and mechanical ventilation between March 2015 and July 2018 were included. TUS and Amylase levels were measured during the first 24 hours and repeated 48 hours after orotracheal intubation. Forty-three patients with a median age of 34 years (17-82) were included. TUS had a sensitivity of 100% and specificity of 96.3% as a predictor of VAP within the first 48 hours when nonpattern A was observed. TA levels > 200 UI/L in the first 48 hours had a sensitivity of 87.5%, and specificity of 63% as a predictor of VAP. Moreover, no benefit of TUS plus TA compared to TUS alone as a predictor of VAP was found. The identification of abnormal TUS patterns in the first 48 hours of orotracheal intubation is a significant predictor of VAP in neurocritical patients.

Including Organ Dysfunctions in a Predictive Score for Nosocomial Pneumonia After Cardiothoracic Surgery

BACKGROUND

Clinical diagnosis of ICU-acquired pneumonia after cardiothoracic surgery is challenging. Johanson criteria (chest radiograph infiltrate, purulent tracheal secretions, fever, and leukocytosis) fail in half the cases. A high Clinical Pulmonary Infection Score (CPIS) and ≥ 2-point increase in Sequential Organ Failure Assessment (SOFA) score (SOFA↑ ≥ 2) may improve diagnosis. The aim of the study was to evaluate whether CPIS or SOFA↑ ≥ 2 contributes to predict ICU-acquired pneumonia in subjects after cardiothoracic surgery.

METHODS

We used a prospective observational design. Spiegelhalter-Knill-Jones scoring systems including CPIS or SOFA↑ ≥ 2, together with other clinical and laboratory variables, were developed in a derivation cohort. A positive quantitative pulmonary sample culture was required to confirm ICU-acquired pneumonia. Area under the receiver operating characteristic curve (AUROC) was computed for each of the 2 scoring systems. The best system was evaluated in a validation cohort.

RESULTS

Derivation and validation cohorts included 172 and 108 subjects, with 410 and 216 suspected ICU-acquired pneumonia episodes, respectively. AUROC was 0.53 ± 0.03 for CPIS (P = .29) and 0.54 ± 0.03 for SOFA↑ ≥ 2 (P = .29). Adding purulent tracheal secretions and leukocytosis to SOFA↑ ≥ 2 (SOFA model) increased AUROC to 0.65 ± 0.03 (P < .001). Adding catecholamine use to CPIS (CPIS model) increased AUROC only slightly, to 0.57 ± 0.03. The probabilities predicted by the SOFA model were reliable, especially when high or low.

CONCLUSIONS

A clinical scoring system including at least SOFA↑ ≥ 2 increase barely improved ICU-acquired pneumonia prediction in subjects after cardiothoracic surgery.

Prognostic evaluation of Acinetobacter baumannii ventilator-associated pneumonia in COVID-19

BACKGROUND

Since the emergence of the pandemic of SARS-CoV-2, a high reported incidence of VAP in COVID-19 sustained by carbapenem resistant Acinetobacter baumannii (CRAB) has been observed, but data are scarce to date.

MATERIALS AND METHODS

We retrospectively collected COVID-19 patients who developed CRAB-VAP - defined according to Center for Diseases Control (CDC) 2020 criteria and European Society of Clinical Microbiology and Infectious Diseases (ESCMID) or Infectious Diseases Society of America (IDSA) guidelines - to describe characteristics and outcome.

RESULTS

Among 21 patients with CRAB-VAP in COVID-19, median age was 66 years (IQR 41-80). Median time of VAP-onset was 7 days (IQR 0-28 days) from ICU - admission and 76.2% had septic shock. Treatment regimens were all colistin-based, in 28% (n=6) including ampicillin/sulbactam and rifampicin. In three cases, cefiderocol was started as rescue. Survival rate at 28-days was 35% (n=7).

CONCLUSION

Non-fermenting Gram-negative bacteria are an emerging aetiology of VAP in COVID-19 patients. This underscores the urgent need for proper microbiological identification to address therapies and infection control protocols.

Positive Airway Cultures in Dogs and Cats Receiving Mechanical Ventilation for Tick Paralysis

Animals with tick paralysis often require mechanical ventilation (MV) but previous publications have identified knowledge gaps regarding the development of bacterial pneumonia, and the specific pathogens involved. The objectives of this study were to describe the clinical course and culture and susceptibility profiles of bacteria isolated from airway samples of dogs and cats mechanically ventilated for tick paralysis that had positive airway cultures. Medical records were reviewed, and cases included if they had a positive airway sample culture during MV for tick paralysis. Twenty-four dogs and two cats were included. Most (85%) received empirical antimicrobials before airway sampling. The most common organisms isolated included Staphylococcus spp. (11), Klebsiella spp. (9), Enterococcus faecalis (8), Escherichia coli (6), Enterococcus faecium (3), Pseudomonas aeruginosa (4), and Mycoplasma spp. (3). Evidence of aspiration pneumonia was present in 22/25 (88%) cases that had thoracic radiographs performed. Seventy-seven percent of cases received antimicrobials to which the cultured bacteria were susceptible during hospitalisation. The median duration of MV was 4 days (range 1-10). Most (77%) survived to discharge, 19% were euthanised, and one died. In a multivariable logistic regression analysis it was identified that selection of antimicrobials to which the causative bacteria are susceptible was associated with survival to discharge (Odds ratio 45.8, p = 0.014; 95%CI 1.98-14,808), as was length of MV, with every day an animal is ventilated associated with a 4.7 times increased chance of survival (p = 0.015; 95% CI 1.21-78.4).