Ventilator-associated pneumonia in critically ill patients with COVID-19 infection, a narrative review

Mechanical Ventilator-Associated Pneumonia in the COVID-19 Pandemic Era: A Critical Challenge in the Intensive Care Units

Background/Objectives: Ventilator-associated pneumonia (VAP) is the most common nosocomial infection encountered in the intensive care unit (ICU) and is associated with prolonged hospitalization and increased mortality. We evaluated the causative pathogens involved and their resistance to the major classes of antibiotics in patients with VAP and assessed the differences between patients with and without coronavirus disease 2019 (COVID-19). Materials and Methods: This study was a single-center, cross-sectional, retrospective analysis involving 122 patients who were hospitalized in the ICU of Târgu Mureș County Clinical Hospital from 1 April 2021, to 1 April 2023. This study compares patients with VAP in COVID-19 and non-COVID-19 groups, examining the clinical progression, duration of ventilation and hospitalization, mortality, pathogen distribution, and the emergence of multidrug-resistant strains. Results: A length of stay in the ICU exceeding 11.5 days was associated with the development of multidrug-resistant (MDR) infections (AUC: 0.708, p < 0.001). Similarly, a duration of MV exceeding 196 h was associated with MDR acquisition (AUC: 0.695, p = 0.002). Additionally, a Clinical Pulmonary Infection Score (CPIS) greater than 5 was associated with MDR development (AUC: 0.854, p < 0.001) in the whole group of patients. The most commonly isolated strains were Acinetobacter spp., Pseudomonas spp., Klebsiella spp., and Staphylococcus aureus. Among non-COVID-19 patients, there was a notably higher frequency of MDR Acinetobacter baumannii. A bacterial resistance to carbapenems was found in Acinetobacter spp. (51.6%), Klebsiella spp. (22.6%), and Pseudomonas spp. (25.8%). Conclusions: COVID-19 patients experienced longer ventilation, higher mortality, and an increased risk of developing MDR. Carbapenem resistance was universal in Acinetobacter spp. and Klebsiella pneumoniae, whereas resistance in Pseudomonas aeruginosa was more prevalent among non-COVID-19 patients. The Clinical Pulmonary Infection Score (CPIS) strongly correlates with developing MDR pathogens in both patient groups.

Herpesviridae and Atypical Bacteria Co-Detections in Lower Respiratory Tract Samples of SARS-CoV-2-Positive Patients Admitted to an Intensive Care Unit

Shortly after the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), cases of viral, bacterial, and fungal coinfections in hospitalized patients became evident. This retrospective study investigates the prevalence of multiple pathogen co-detections in 1472 lower respiratory tract (LRT) samples from 229 SARS-CoV-2-positive patients treated in the largest intensive care unit (ICU) in Slovenia. In addition to SARS-CoV-2, (rt)RT-PCR tests were used to detect cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus 1 (HSV-1), herpes simplex virus 2 (HSV-2), varicella zoster virus (VZV), and atypical bacteria: Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella pneumophila/spp. At least one co-detection was observed in 89.1% of patients. EBV, HSV-1, and CMV were the most common, with 74.7%, 58.1%, and 38.0% of positive patients, respectively. The median detection time of EBV, HSV-1, and CMV after initial SARS-CoV-2 confirmation was 11 to 20 days. Bronchoalveolar lavage (BAL) and tracheal aspirate (TA) samples showed equivalent performance for the detection of EBV, CMV, and HSV-1 in patients with both available samples. Our results indicate that SARS-CoV-2 infection could be a risk factor for latent herpesvirus reactivation, especially HSV-1, EBV, and CMV. However, additional studies are needed to elucidate the clinical importance of these findings.

Hospital-acquired and ventilator-associated pneumonia caused by multidrug-resistant Gram-negative pathogens: Understanding epidemiology, resistance patterns, and implications with COVID-19

The ongoing spread of antimicrobial resistance has complicated the treatment of bacterial hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). Gram-negative pathogens, especially those with multidrug-resistant profiles, including Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., Pseudomonas aeruginosa, and Acinetobacter spp., are important culprits in this type of infections. Understanding the determinants of resistance in pathogens causing pneumonia is ultimately stressing, especially in the shadows of the COVID-19 pandemic, when bacterial lung infections are considered a top priority that has become urgent to revise. Globally, the increasing prevalence of these pathogens in respiratory samples represents a significant infection challenge, with major limitations of treatment options and poor clinical outcomes. This review will focus on the epidemiology of HAP and VAP and will present the roles and the antimicrobial resistance patterns of implicated multidrug-resistant (MDR) Gram-negative pathogens like carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA), carbapenem-resistant Enterobacterales (CRE), as well as colistin-resistant Gram-negative pathogens and extended-spectrum β-lactamase (ESBL)-producing Enterobacterales. While emerging from the COVID-19 pandemic, perspectives and conclusions are drawn from findings of HAP and VAP caused by MDR Gram-negative bacteria in patients with COVID-19.

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.

Mortality, incidence, and microbiological documentation of ventilated acquired pneumonia (VAP) in critically ill patients with COVID-19 or influenza

BACKGROUND

Data on ventilator associated pneumonia (VAP) in COVID-19 and influenza patients admitted to intensive care units (ICU) are scarce. This study aimed to estimate day-60 mortality related to VAP in ICU patients ventilated for at least 48 h, either for COVID-19 or for influenza, and to describe the epidemiological characteristics in each group of VAP.

DESIGN

Multicentre retrospective observational study.

SETTING

Eleven ICUs of the French OutcomeRea™ network.

PATIENTS

Patients treated with invasive mechanical ventilation (IMV) for at least 48 h for either COVID-19 or for flu.

RESULTS

Of the 585 patients included, 503 had COVID-19 and 82 had influenza between January 2008 and June 2021. A total of 232 patients, 209 (41.6%) with COVID-19 and 23 (28%) with influenza, developed 375 VAP episodes. Among the COVID-19 and flu patients, VAP incidences for the first VAP episode were, respectively, 99.2 and 56.4 per 1000 IMV days (p < 0.01), and incidences for all VAP episodes were 32.8 and 17.8 per 1000 IMV days (p < 0.01). Microorganisms of VAP were Gram-positive cocci in 29.6% and 23.5% of episodes of VAP (p < 0.01), respectively, including Staphylococcus aureus in 19.9% and 11.8% (p = 0.25), and Gram-negative bacilli in 84.2% and 79.4% (p = 0.47). In the overall cohort, VAP was associated with an increased risk of day-60 mortality (aHR = 1.77 [1.36; 2.30], p < 0.01), and COVID-19 had a higher mortality risk than influenza (aHR = 2.22 [CI 95%, 1.34; 3.66], p < 0.01). VAP was associated with increased day-60 mortality among COVID-19 patients (aHR = 1.75 [CI 95%, 1.32; 2.33], p < 0.01), but not among influenza patients (aHR = 1.75 [CI 95%, 0.48; 6.33], p = 0.35).

CONCLUSION

The incidence of VAP was higher in patients ventilated for at least 48 h for COVID-19 than for influenza. In both groups, Gram-negative bacilli were the most frequently detected microorganisms. In patients ventilated for either COVID-19 or influenza VAP and COVID-19 were associated with a higher risk of mortality.

Multidrug-resistant VAP before and during the COVID-19 pandemic among hospitalized patients in a tertiary private hospital

Background

There is limited data on ventilator-associated pneumonia (VAP) and multidrug-resistant VAP (MDR VAP) among COVID-19 patients.

Methods

A retrospective study in a single, tertiary, private hospital in the Philippines was conducted comparing the incidence, profile, and patient outcomes of MDR VAP during the pre-COVID-19 (2018-2019) and COVID-19 (2020-2021) periods.

Results

In total, 80/362 (22%) patients developed VAP, 27/204 (33.75%) from pre-COVID-19 and 53/158 (66.25%) from the COVID-19 period, respectively. The majority were male [20/27 (74%) vs 34/53 (64%)], with a median age of 66 (range 35-90) and 67 (range 32-92) years in each period, respectively. Comorbidities were similar, except cardiovascular disease (14/27 vs 11/53 patients, p-value 0.005) and chronic lung disease (14/27 vs 9/53 patients, p-value 0.0012). VAP incidence density was 19.3/1000 and 27.8/1000 ventilator days (p-value 0.9819)]; median length of stay before VAP for pre- and COVID-19 periods was 17 and 10 days, respectively (p-value <0.0001). Extended-spectrum β lactamase (ESBL)-producing resistance increased significantly [1/27 (3.7%) pre-COVID-19 vs 15/53 (28.3%)] during COVID-19, while Carbapenem-resistant Enterobacteriaceae resistance was higher in the pre-COVID-19 period (15/27 [56%] vs 10/53 [19%]). Mortality was high in both periods at 93% and 83%, respectively. On multivariate analysis, only female gender was associated with MDR VAP in the COVID-19 period (OR =3.47, [CI 1.019, 11.824], p-value < 0.047).

Conclusion

The frequency of VAP and MDR VAP increased during the COVID-19 period, despite a shorter duration of hospital stay. The mortality of VAP was extremely high. Factors associated with increased risk of VAP and COVID-19 need to be studied further, and preventive measures should be prioritized.

Impact of outdoor air pollution on severity and mortality in COVID-19 pneumonia

The relationship between exposure to air pollution and the severity of coronavirus disease 2019 (COVID-19) pneumonia and other outcomes is poorly understood. Beyond age and comorbidity, risk factors for adverse outcomes including death have been poorly studied. The main objective of our study was to examine the relationship between exposure to outdoor air pollution and the risk of death in patients with COVID-19 pneumonia using individual-level data. The secondary objective was to investigate the impact of air pollutants on gas exchange and systemic inflammation in this disease. This cohort study included 1548 patients hospitalised for COVID-19 pneumonia between February and May 2020 in one of four hospitals. Local agencies supplied daily data on environmental air pollutants (PM10, PM2.5, O3, NO2, NO and NOX) and meteorological conditions (temperature and humidity) in the year before hospital admission (from January 2019 to December 2019). Daily exposure to pollution and meteorological conditions by individual postcode of residence was estimated using geospatial Bayesian generalised additive models. The influence of air pollution on pneumonia severity was studied using generalised additive models which included: age, sex, Charlson comorbidity index, hospital, average income, air temperature and humidity, and exposure to each pollutant. Additionally, generalised additive models were generated for exploring the effect of air pollution on C-reactive protein (CRP) level and SpO2/FiO2 at admission. According to our results, both risk of COVID-19 death and CRP level increased significantly with median exposure to PM10, NO2, NO and NOX, while higher exposure to NO2, NO and NOX was associated with lower SpO2/FiO2 ratios. In conclusion, after controlling for socioeconomic, demographic and health-related variables, we found evidence of a significant positive relationship between air pollution and mortality in patients hospitalised for COVID-19 pneumonia. Additionally, inflammation (CRP) and gas exchange (SpO2/FiO2) in these patients were significantly related to exposure to air pollution.

Kinetics of C-Reactive Protein and Procalcitonin in the Early Identification of ICU-Acquired Infections in Critically Ill COVID-19 Patients

The SARS-CoV-2 infection is a cause of hypoxemic acute respiratory failure, leading to frequent intensive care unit (ICU) admission. Due to invasive organ support and immunosuppressive therapies, these patients are prone to nosocomial infections. Our aim was to assess the value of daily measurements of C-reactive protein (CRP) and Procalcitonin (PCT) in the early identification of ICU-acquired infections in COVID-19 patients.

METHODS

We undertook a prospective observational cohort study (12 months). All adult mechanically ventilated patients admitted for ≥72 h to ICU with COVID-19 pneumonia were divided into an infected group (n = 35) and a non-infected group (n = 83). Day 0 was considered as the day of the diagnosis of infection (infected group) and Day 10 was that of ICU stay (non-infected group). The kinetics of CRP and PCT were assessed from Day -10 to Day 10 and evaluated using a general linear model, univariate, repeated-measures analysis.

RESULTS

118 patients (mean age 63 years, 74% males) were eligible for the analysis. The groups did not differ in patient age, gender, CRP and PCT serum levels at ICU admission. However, the infected group encompassed patients with a higher severity (SOFA score at ICU admission, p = 0.009) and a higher 28-day mortality (p < 0.001). Before D0, CRP kinetics showed a significant increase in infected patients, whereas in noninfected it remained almost unchanged (p < 0.001), while PCT kinetics did not appear to retain diagnostic value to predict superinfection in COVID-19 patients (p = 0.593).

CONCLUSION

COVID-19 patients who developed ICU-acquired infections exhibited different biomarker kinetics before the diagnosis of those infections. Daily CRP monitoring and the recognition of the CRP kinetics could be useful in the prediction of ICU-acquired infections.

ICU-Acquired Colonization and Infection Related to Multidrug-Resistant Bacteria in COVID-19 Patients: A Narrative Review

A large proportion of ICU-acquired infections are related to multidrug-resistant bacteria (MDR). Infections caused by these bacteria are associated with increased mortality, and prolonged duration of mechanical ventilation and ICU stay. The aim of this narrative review is to report on the association between COVID-19 and ICU-acquired colonization or infection related to MDR bacteria. Although a huge amount of literature is available on COVID-19 and MDR bacteria, only a few clinical trials have properly evaluated the association between them using a non-COVID-19 control group and accurate design and statistical methods. The results of these studies suggest that COVID-19 patients are at a similar risk of ICU-acquired MDR colonization compared to non-COVID-19 controls. However, a higher risk of ICU-acquired infection related to MDR bacteria has been reported in several studies, mainly ventilator-associated pneumonia and bloodstream infection. Several potential explanations could be provided for the high incidence of ICU-acquired infections related to MDR. Immunomodulatory treatments, such as corticosteroids, JAK2 inhibitors, and IL-6 receptor antagonist, might play a role in the pathogenesis of these infections. Additionally, a longer stay in the ICU was reported in COVID-19 patients, resulting in higher exposure to well-known risk factors for ICU-acquired MDR infections, such as invasive procedures and antimicrobial treatment. Another possible explanation is the surge during successive COVID-19 waves, with excessive workload and low compliance with preventive measures. Further studies should evaluate the evolution of the incidence of ICU-acquired infections related to MDR bacteria, given the change in COVID-19 patient profiles. A better understanding of the immune status of critically ill COVID-19 patients is required to move to personalized treatment and reduce the risk of ICU-acquired infections. The role of specific preventive measures, such as targeted immunomodulation, should be investigated.

Ventilator-Associated Pneumonia in COVID-19 Patients Admitted in Intensive Care Units: Relapse, Therapeutic Failure and Attributable Mortality-A Multicentric Observational Study from the OutcomeRea Network

Introduction: Ventilator-associated pneumonia (VAP) incidence is high among critically ill COVID-19 patients. Its attributable mortality remains underestimated, especially for unresolved episodes. Indeed, the impact of therapeutic failures and the determinants that potentially affect mortality are poorly evaluated. We assessed the prognosis of VAP in severe COVID-19 cases and the impact of relapse, superinfection, and treatment failure on 60-day mortality. Methods: We evaluated the incidence of VAP in a multicenter prospective cohort that included adult patients with severe COVID-19, who required mechanical ventilation for ≥48 h between March 2020 and June 2021. We investigated the risk factors for 30-day and 60-day mortality, and the factors associated with relapse, superinfection, and treatment failure. Results: Among 1424 patients admitted to eleven centers, 540 were invasively ventilated for 48 h or more, and 231 had VAP episodes, which were caused by Enterobacterales (49.8%), P. aeruginosa (24.8%), and S. aureus (22%). The VAP incidence rate was 45.6/1000 ventilator days, and the cumulative incidence at Day 30 was 60%. VAP increased the duration of mechanical ventilation without modifying the crude 60-day death rate (47.6% vs. 44.7% without VAP) and resulted in a 36% increase in death hazard. Late-onset pneumonia represented 179 episodes (78.2%) and was responsible for a 56% increase in death hazard. The cumulative incidence rates of relapse and superinfection were 45% and 39.5%, respectively, but did not impact death hazard. Superinfection was more frequently related to ECMO and first episode of VAP caused by non-fermenting bacteria. The risk factors for treatment failure were an absence of highly susceptible microorganisms and vasopressor need at VAP onset. Conclusions: The incidence of VAP, mainly late-onset episodes, is high in COVID-19 patients and associated with an increased risk of death, similar to that observed in other mechanically ventilated patients. The high rate of VAP due to difficult-to-treat microorganisms, pharmacokinetic alterations induced by renal replacement therapy, shock, and ECMO likely explains the high cumulative risk of relapse, superinfection, and treatment failure.

Effect of SARS-CoV-2 infection and pandemic period on healthcare-associated infections acquired in intensive care units

OBJECTIVES

To compare the occurrence of healthcare-associated infections acquired in intensive care units (HAI-ICUs) in France among patients with COVID-19 and those without it in 2020 and the latter with that in patients before the COVID-19 pandemic.

METHODS

Multicentre HAI-ICU surveillance network (REA-REZO) data were used to identify 3 groups: 2019 patients (2019Control), a COVID-19 group (2020Cov), and a non-COVID-19 group (2020NonCov). The primary outcome was the occurrence of HAI-ICU (ventilator-associated pneumonia [VAP], bloodstream infections [BSIs], catheter-related bacteraemia). Standardized infection ratios of VAP were calculated for each quarter in 2020 and compared with those in 2019.

RESULTS

A total of 30 105 patients were included in 2020: 23 798 in the 2020NonCov group, 4465 in 2020Cov group, and 39 635 patients in the 2019Control group. The frequency of VAP was strikingly greater in the 2020Cov group: 35.6 (33.4-37.8) episodes/1000 days of mechanical ventilation versus 18.4 (17.6-19.2) in the 2020NonCov group. VAP standardized infection ratio was high in 2020 patients, particularly during the 2 quarters corresponding to the 2 waves. BSI/1000 days were more frequent in the 2020Cov group (6.4% [6.4-6.4%] vs. 3.9% [3.8-3.9%] in the 2020NonCov group). VAP and BSI were also more frequent in the 2020NonCov group than in the 2019Control group. The microbial epidemiology was only slightly different.

DISCUSSION

The data presented here indicate that HAI-ICUs were more frequent during the COVID-19 period, whether the patients were admitted for COVID-19 or, to a lesser extent, for another cause. This implies that managing patients with severe disease in a pandemic context carries risks for all patients.