A Comparison of the Mortality Risk Associated With Ventilator-Acquired Bacterial Pneumonia and Nonventilator ICU-Acquired Bacterial Pneumonia

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.

Rebound Inverts the Staphylococcus aureus Bacteremia Prevention Effect of Antibiotic Based Decontamination Interventions in ICU Cohorts with Prolonged Length of Stay

Could rebound explain the paradoxical lack of prevention effect against Staphylococcus aureus blood stream infections (BSIs) with antibiotic-based decontamination intervention (BDI) methods among studies of ICU patients within the literature? Two meta-regression models were applied, each versus the group mean length of stay (LOS). Firstly, the prevention effects against S. aureus BSI [and S. aureus VAP] among 136 studies of antibiotic-BDI versus other interventions were analyzed. Secondly, the S. aureus BSI [and S. aureus VAP] incidence in 268 control and intervention cohorts from studies of antibiotic-BDI versus that among 165 observational cohorts as a benchmark was modelled. In model one, the meta-regression line versus group mean LOS crossed the null, with the antibiotic-BDI prevention effect against S. aureus BSI at mean LOS day 7 (OR 0.45; 0.30 to 0.68) inverted at mean LOS day 20 (OR 1.7; 1.1 to 2.6). In model two, the meta-regression line versus group mean LOS crossed the benchmark line, and the predicted S. aureus BSI incidence for antibiotic-BDI groups was 0.47; 0.09-0.84 percentage points below versus 3.0; 0.12-5.9 above the benchmark in studies with 7 versus 20 days mean LOS, respectively. Rebound within the intervention groups attenuated and inverted the prevention effect of antibiotic-BDI against S. aureus VAP and BSI, respectively. This explains the paradoxical findings.

A hybrid modeling framework for generalizable and interpretable predictions of ICU mortality across multiple hospitals

The development of reliable mortality risk stratification models is an active research area in computational healthcare. Mortality risk stratification provides a standard to assist physicians in evaluating a patient's condition or prognosis objectively. Particular interest lies in methods that are transparent to clinical interpretation and that retain predictive power once validated across diverse datasets they were not trained on. This study addresses the challenge of consolidating numerous ICD codes for predictive modeling of ICU mortality, employing a hybrid modeling approach that integrates mechanistic, clinical knowledge with mathematical and machine learning models . A tree-structured network connecting independent modules that carry clinical meaning is implemented for interpretability. Our training strategy utilizes graph-theoretic methods for data analysis, aiming to identify the functions of individual black-box modules within the tree-structured network by harnessing solutions from specific max-cut problems. The trained model is then validated on external datasets from different hospitals, demonstrating successful generalization capabilities, particularly in binary-feature datasets where label assessment involves extrapolation.

Application of a multiplex molecular pneumonia panel and real-world impact on antimicrobial stewardship among patients with hospital-acquired and ventilator-associated pneumonia in intensive care units

BACKGROUND

The optimal timing for applying the BioFire FilmArray Pneumonia Panel (FAPP) in intensive care unit (ICU) patients with hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP) remains undefined, and there are limited data on its impact on antimicrobial stewardship.

METHODS

This retrospective study was conducted at a referral hospital in Taiwan from November 2019 to October 2022. Adult ICU patients with HAP/VAP who underwent FAPP testing were enrolled. Patient data, FAPP results, conventional microbiological testing results, and the real-world impact of FAPP results on antimicrobial therapy adjustments were assessed. Logistic regression was used to determine the predictive factors for bacterial detection by FAPP.

RESULTS

Among 592 respiratory specimens, including 564 (95.3%) endotracheal aspirate specimens, 19 (3.2%) expectorated sputum specimens and 9 (1.5%) bronchoalveolar lavage specimens, from 467 patients with HAP/VAP, FAPP testing yielded 368 (62.2%) positive results. Independent predictors for positive bacterial detection by FAPP included prolonged hospital stay (odds ratio [OR], 3.14), recent admissions (OR, 1.59), elevated C-reactive protein levels (OR, 1.85), Acute Physiology and Chronic Health Evaluation II scores (OR, 1.58), and septic shock (OR, 1.79). Approximately 50% of antimicrobial therapy for infections caused by Gram-negative bacteria and 58.4% for Gram-positive bacteria were adjusted or confirmed after obtaining FAPP results.

CONCLUSIONS

This study identified several factors predicting bacterial detection by FAPP in critically ill patients with HAP/VAP. More than 50% real-world clinical practices were adjusted or confirmed based on the FAPP results. Clinical algorithms for the use of FAPP and antimicrobial stewardship guidelines may further enhance its benefits.

Impact of Multiplex PCR in the Therapeutic Management of Severe Bacterial Pneumonia

Pneumonia is a common and severe illness that requires prompt and effective management. Advanced, rapid, and accurate tools are needed to diagnose patients with severe bacterial pneumonia, and to rapidly select appropriate antimicrobial therapy, which must be initiated within the first few hours of care. Two multiplex molecular tests, Unyvero HPN and FilmArray Pneumonia+ Panel, have been developed using the multiplex polymerase chain reaction (mPCR) technique to rapidly identify pathogens and their main antibiotic resistance mechanisms from patient respiratory specimens. Performance evaluation of these tests showed strong correlations with reference techniques. However, good knowledge of their indications, targets, and limitations is essential. Collaboration with microbiologists is, therefore, crucial for their appropriate use. Under these conditions, and with standardized management, these rapid tests can improve the therapeutic management of severe pneumonia faster, more precisely, and with narrow-spectrum antibiotic therapy. Further randomized controlled trials are needed to address the many unanswered questions about multiplex rapid molecular testing during the diagnosis and the management of severe pneumonia. This narrative review will address the current knowledge, advantages, and disadvantages of these tests, and propose solutions for their routine use.

Single-drug versus combination antimicrobial therapy in critically ill patients with hospital-acquired pneumonia and ventilator-associated pneumonia due to Gram-negative pathogens: a multicenter retrospective cohort study

KEY MESSAGES

In this study including 391 critically ill patients with nosocomial pneumonia due to Gram-negative pathogens, combination therapy was not associated with a reduced hazard of death at Day 28 or a greater likelihood of clinical cure at Day 14. No over-risk of AKI was observed in patients receiving combination therapy.

BACKGROUND

The benefits and harms of combination antimicrobial therapy remain controversial in critically ill patients with hospital-acquired pneumonia (HAP), ventilated HAP (vHAP) or ventilator-associated pneumonia (VAP) involving Gram-negative bacteria.

METHODS

We included all patients in the prospective multicenter OutcomeRea database with a first HAP, vHAP or VAP due to a single Gram-negative bacterium and treated with initial adequate single-drug or combination therapy. The primary endpoint was Day-28 all-cause mortality. Secondary endpoints were clinical cure rate at Day 14 and a composite outcome of death or treatment-emergent acute kidney injury (AKI) at Day 7. The average effects of combination therapy on the study endpoints were investigated through inverse probability of treatment-weighted regression and multivariable regression models. Subgroups analyses were performed according to the resistance phenotype of the causative pathogens (multidrug-resistant or not), the pivotal (carbapenems or others) and companion (aminoglycosides/polymyxins or others) drug classes, the duration of combination therapy (< 3 or ≥ 3 days), the SOFA score value at pneumonia onset (< 7 or ≥ 7 points), and in patients with pneumonia due to non-fermenting Gram-negative bacteria, pneumonia-related bloodstream infection, or septic shock.

RESULTS

Among the 391 included patients, 151 (38.6%) received single-drug therapy and 240 (61.4%) received combination therapy. VAP (overall, 67.3%), vHAP (16.4%) and HAP (16.4%) were equally distributed in the two groups. All-cause mortality rates at Day 28 (overall, 31.2%), clinical cure rate at Day 14 (43.7%) and the rate of death or AKI at Day 7 (41.2%) did not significantly differ between the groups. In inverse probability of treatment-weighted analyses, combination therapy was not independently associated with the likelihood of all-cause death at Day 28 (adjusted odd ratio [aOR], 1.14; 95% confidence interval [CI] 0.73-1.77; P = 0.56), clinical cure at Day 14 (aOR, 0.79; 95% CI 0.53-1.20; P = 0.27) or death or AKI at Day 7 (aOR, 1.07; 95% CI 0.71-1.63; P = 0.73). Multivariable regression models and subgroup analyses provided similar results.

CONCLUSIONS

Initial combination therapy exerts no independent impact on Day-28 mortality, clinical cure rate at Day 14, and the hazard of death or AKI at Day 7 in critically ill patients with mono-bacterial HAP, vHAP or VAP due to Gram-negative bacteria.

Structure-Interaction Relationship of Polymyxins with Lung Surfactant

Multidrug-resistant Gram-negative bacteria present an urgent and formidable threat to the global public health. Polymyxins have emerged as a last-resort therapy against these 'superbugs'; however, their efficacy against pulmonary infection is poor. In this study, we integrated chemical biology and molecular dynamics simulations to examine how the alveolar lung surfactant significantly reduces polymyxin antibacterial activity. We discovered that lung surfactant is a phospholipid-based permeability barrier against polymyxins, compromising their efficacy against target bacteria. Next, we unraveled the structure-interaction relationship between polymyxins and lung surfactant, elucidating the thermodynamics that govern the penetration of polymyxins through this critical surfactant layer. Moreover, we developed a novel analog, FADDI-235, which exhibited potent activity against Gram-negative bacteria, both in the presence and absence of lung surfactant. These findings shed new light on the sequestration mechanism of lung surfactant on polymyxins and importantly pave the way for the rational design of new-generation lipopeptide antibiotics to effectively treat Gram-negative bacterial pneumonia.

Management strategies for severe Pseudomonas aeruginosa infections

PURPOSE OF REVIEW

This review focuses on the management of severe Pseudomonas aeruginosa infections in critically ill patients.

RECENT FINDINGS

Pseudomonas aeruginosa is the most common pathogen in intensive care; the main related infections are nosocomial pneumonias, then bloodstream infections. Antimicrobial resistance is common; despite new antibiotics, it is associated with increased mortality, and can lead to a therapeutic deadlock.

SUMMARY

Carbapenem resistance in difficult-to-treat P. aeruginosa (DTR-PA) strains is primarily mediated by loss or reduction of the OprD porin, overexpression of the cephalosporinase AmpC, and/or overexpression of efflux pumps. However, the role of carbapenemases, particularly metallo-β-lactamases, has become more important. Ceftolozane-tazobactam, ceftazidime-avibactam and imipenem-relebactam are useful against DTR phenotypes (noncarbapenemase producers). Other new agents, such as aztreonam-ceftazidime-avibactam or cefiderocol, or colistin, might be effective for carbapenemase producers. Regarding nonantibiotic agents, only phages might be considered, pending further clinical trials. Combination therapy does not reduce mortality, but may be necessary for empirical treatment. Short-term treatment of severe P. aeruginosa infections should be preferred when it is expected that the clinical situation resolves rapidly.

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.

Severe infections caused by difficult-to-treat Gram-negative bacteria

PURPOSE OF REVIEW

Antimicrobial resistance (AMR) in Gram-negative bacteria (GNB) poses a significant global health concern, contributing to increased infections, mortality rates, and healthcare costs. This review discusses the main clinical manifestations, therapeutic options, and recent findings in managing antibiotic-resistant GNB, with a focus on difficult-to-treat infections.

RECENT FINDINGS

Difficult-to-treat resistance (DTR) is a novel classification that identifies GNB exhibiting intermediate or resistant phenotypes to first-line agents in the carbapenem, beta-lactam, and fluoroquinolone categories. The main pathogens implicated in severe infections include DTR Enterobacterales, DTR Pseudomonas aeruginosa , and DTR Acinetobacter baumannii. Although the clinical implications of DTR strains are still under investigation, certain studies have linked them to prolonged hospital stays and poor patient outcomes.

SUMMARY

Severe infections caused by DTR-GNB pose a formidable challenge for healthcare providers and represent a growing global health issue. The proper administration and optimization of novel antibiotics at our disposal are of paramount importance for combating bacterial resistance and improving patient prognosis.

Non-ventilator-associated ICU-acquired pneumonia (NV-ICU-AP) in patients with acute exacerbation of COPD: From the French OUTCOMEREA cohort

BACKGROUND

Non-ventilator-associated ICU-acquired pneumonia (NV-ICU-AP), a nosocomial pneumonia that is not related to invasive mechanical ventilation (IMV), has been less studied than ventilator-associated pneumonia, and never in the context of patients in an ICU for severe acute exacerbation of chronic obstructive pulmonary disease (AECOPD), a common cause of ICU admission. This study aimed to determine the factors associated with NV-ICU-AP occurrence and assess the association between NV-ICU-AP and the outcomes of these patients.

METHODS

Data were extracted from the French ICU database, OutcomeRea™. Using survival analyses with competing risk management, we sought the factors associated with the occurrence of NV-ICU-AP. Then we assessed the association between NV-ICU-AP and mortality, intubation rates, and length of stay in the ICU.

RESULTS

Of the 844 COPD exacerbations managed in ICUs without immediate IMV, NV-ICU-AP occurred in 42 patients (5%) with an incidence density of 10.8 per 1,000 patient-days. In multivariate analysis, prescription of antibiotics at ICU admission (sHR, 0.45 [0.23; 0.86], p = 0.02) and no decrease in consciousness (sHR, 0.35 [0.16; 0.76]; p < 0.01) were associated with a lower risk of NV-ICU-AP. After adjusting for confounders, NV-ICU-AP was associated with increased 28-day mortality (HR = 3.03 [1.36; 6.73]; p < 0.01), an increased risk of intubation (csHR, 5.00 [2.54; 9.85]; p < 0.01) and with a 10-day increase in ICU length of stay (p < 0.01).

CONCLUSION

We found that NV-ICU-AP incidence reached 10.8/1000 patient-days and was associated with increased risks of intubation, 28-day mortality, and longer stay for patients admitted with AECOPD.

Changes in the prevalence of pathogens causing hospital-acquired bacterial pneumonia and the impact of their antimicrobial resistance patterns on clinical outcomes: A propensity-score-matched study

BACKGROUND

This study aimed to evaluate changes in the prevalence of pathogens causing hospital-acquired bacterial pneumonia (HABP) and their antimicrobial resistance patterns in recent years, and to identify risk factors for 28-day all-cause mortality (ACM) in patients with HABP.

METHODS

A propensity-score-matched study was performed by randomly allocating patients with ventilator-associated and non-ventilator-associated bacterial pneumonia admitted to two university hospitals between 2011 and 2021.

RESULTS

In total, 17,250 patients with HABP were enrolled. The annual incidence of Staphylococcus aureus HABP decreased during the study period, while that of Klebsiella pneumoniae HABP increased significantly each year. Over the same period, the resistance rate of S. aureus to methicillin decreased from 88.4% to 64.4%, while the non-susceptibility rate of K. pneumoniae to carbapenems increased from 0% to 38%. HABP caused by A. baumannii [adjusted odds ratio (aOR) 1.50, 95% confidence interval (CI) 1.25-1.79], K. pneumoniae (aOR 1.28, 95% CI 1.16-1.40) and Stenotrophomonas maltophilia (aOR 1.32, 95% CI 1.05-1.66) was a risk factor for 28-day ACM. Patients with HABP caused by methicillin-resistant S. aureus and carbapenem-non-susceptible A. baumannii or K. pneumoniae had a significantly lower probability of survival. HABP with preceding coronavirus disease 2019 (COVID-19) was associated with high 28-day ACM (aOR 5.40, 955 CI 3.03-9.64) and high incidence of bacteraemic pneumonia (aOR 40.55, 95% CI 5.26-312.79).

CONCLUSIONS

This study showed shifting trends in HABP-causing pathogens in terms of annual incidence and resistance rates to major therapeutic antimicrobial agents. HABP-causing bacterial pathogens, their antimicrobial resistance phenotypes, and preceding COVID-19 were significantly associated with progression of HABP to bloodstream infection and 28-day ACM in infected patients.

Rapid Point-of-Care PCR Testing of Drug-Resistant Strains on Endotracheal Aspirate Samples: A Repurposed Effective Tool in the Stepwise Approach of Healthcare-Acquired Pneumonia-A Pilot Study

Healthcare-associated pneumonia (HCAP) is a common nosocomial infection with high morbidity and mortality. Culture-based detection of the etiologic agent and drug susceptibility is time-consuming, potentially leading to the inadequate use of broad-spectrum empirical antibiotic regimens. The aim was to evaluate the diagnostic capabilities of rapid point-of-care multiplex polymerase chain reaction (PCR) assays from the endotracheal aspirate of critically ill patients with HCAP. A consecutive series of 29 intensive care unit (ICU) patients with HCAP and a control group of 28 patients undergoing elective surgical procedures were enrolled in the study. The results of the PCR assays were compared to the culture-based gold standard. The overall accuracy of the PCR assays was 95.12%, with a sensitivity of 92.31% and a specificity of 97.67%. The median time was 90 min for the rapid PCR tests (p < 0.001), while for the first preliminary results of the cultures, it was 48 h (46-72). The overall accuracy for rapid PCR testing in suggesting an adequate antibiotic adjustment was 82.98% (95% CI 69.19-92.35%), with a specificity of 90% (95% CI 55.50-99.75%), a positive predictive value of 96.77% (95% CI 83.30-99.92%), and a negative predictive value of 56.25 (95% CII 29.88-80.25%). This method of rapid point-of-care PCR could effectively guide antimicrobial stewardship in patients with healthcare-acquired pneumonia.

Antimicrobial Resistance in Ventilator-Associated Pneumonia: Predictive Microbiology and Evidence-Based Therapy

Ventilator-associated pneumonia (VAP) is a serious intensive care unit (ICU)-related infection in mechanically ventilated patients that is frequent, as more than half of antibiotics prescriptions in ICU are due to VAP. Various risk factors and diagnostic criteria for VAP have been referred to in different settings. The estimated attributable mortality of VAP can go up to 50%, which is higher in cases of antimicrobial-resistant VAP. When the diagnosis of pneumonia in a mechanically ventilated patient is made, initiation of effective antimicrobial therapy must be prompt. Microbiological diagnosis of VAP is required to optimize timely therapy since effective early treatment is fundamental for better outcomes, with controversy continuing regarding optimal sampling and testing. Understanding the role of antimicrobial resistance in the context of VAP is crucial in the era of continuously evolving antimicrobial-resistant clones that represent an urgent threat to global health. This review is focused on the risk factors for antimicrobial resistance in adult VAP and its novel microbiological tools. It aims to summarize the current evidence-based knowledge about the mechanisms of resistance in VAP caused by multidrug-resistant bacteria in clinical settings with focus on Gram-negative pathogens. It highlights the evidence-based antimicrobial management and prevention of drug-resistant VAP. It also addresses emerging concepts related to predictive microbiology in VAP and sheds lights on VAP in the context of coronavirus disease 2019 (COVID-19).

Pathogen Diagnosis Value of Nanopore Sequencing in Severe Hospital-Acquired Pneumonia Patients

Background

Next-generation sequencing of the metagenome (mNGS) is increasingly used in pathogen diagnosis for infectious diseases due to its short detection time. The time for Oxford Nanopore Technologies (ONT) sequencing-based etiology detection is further shortened compared with that of mNGS, but only a few studies have verified the time advantage and accuracy of ONT sequencing for etiology diagnosis. In 2022, a study confirmed that there was no significant difference in sensitivity and specificity between ONT and mNGS in suspected community-acquired pneumonia patients, which there was no clinical study verified in patients with SHAP.

Methods

From October 24 to November 20, 2022, 10 patients with severe hospital-acquired pneumonia (SHAP) in the Nanfang Hospital intensive care unit (ICU) were prospectively enrolled. Bronchoalveolar lavage fluid (BALF) was collected for ONT sequencing, mNGS, and traditional culture. The differences in pathogen detection time and diagnostic agreement among ONT sequencing, mNGS, traditional culture method, and clinical composite diagnosis were compared.

Results

Compared with mNGS and the traditional culture method, ONT sequencing had a significant advantage in pathogen detection time (9.6±0.7 h versus 24.7±2.7 h versus 132±58 h, P <0.05). The agreement rate between ONT sequencing and the clinical composite diagnosis was 73.3% (kappa value=0.737, P <0.05).

Conclusion

ONT sequencing has a potential advantage for rapidly identifying pathogens.

The Relationship of Nurse and Physician Staffing in Intensive Care Units with Patient Outcomes in Postoperative Patients on Ventilators: An Analysis Using Korean National Health Insurance Data

This study examined the associations of nurse and physician staffing in intensive care units (ICUs) with hospital-acquired pneumonia (HAP) incidence and in-hospital mortality in postoperative patients on ventilators. National Health Insurance claims data and death statistics were used to investigate the nurse staffing level and the presence or absence of a dedicated resident and specialist in each ICU. The participants were patients aged 20-85 who underwent any of 13 surgical procedures and were placed on a ventilator in the ICU after the procedure. Of 11,693 patients, 307 (2.6%) experienced HAP and 1280 (10.9%) died during hospitalization. Compared to hospitals with lower nurse-to-patient ratios, patients in hospitals with higher ratios had statistically significantly higher risks of HAP and in-hospital mortality. The presence of a dedicated resident in the ICU did not statistically significantly affect HAP incidence or in-hospital mortality. The presence of an ICU specialist was statistically significantly associated with in-hospital mortality but not HAP incidence. Our findings suggest that a higher level of nursing staff in the ICU is inversely associated with HAP incidence. The legal standards for nurse staffing in the ICU should be strengthened in order to improve the quality of care and patient safety.

Greater Invasion and Persistence of mcr-1-Bearing Plasmids in Escherichia coli than in Klebsiella pneumoniae

The emergence of the plasmid-borne polymyxin resistance gene mcr-1 threatens the clinical utility of last-line polymyxins. Although mcr-1 has disseminated to various Enterobacterales species, the prevalence of mcr-1 is the highest among Escherichia coli isolates while remaining low in Klebsiella pneumoniae. The reason for such a difference in prevalence has not been investigated. In this study, we examined and compared the biological characteristics of various mcr-1 plasmids in these two bacterial species. Although mcr-1-bearing plasmids were stably maintained in both E. coli and K. pneumoniae, the former presented itself to be superior by demonstrating a fitness advantage while carrying the plasmid. The inter- and intraspecies transferability efficiencies were evaluated for common mcr-1-harboring plasmids (IncX4, IncI2, IncHI2, IncP, and IncF types) with native E. coli and K. pneumoniae strains as donors. Here, we found that the conjugation frequencies of mcr-1 plasmids were significantly higher in E. coli than in K. pneumoniae, regardless of the donor species and Inc types of the mcr-1 plasmids. Plasmid invasion experiments revealed that mcr-1 plasmids displayed greater invasiveness and stability in E. coli than in K. pneumoniae. Moreover, K. pneumoniae carrying mcr-1 plasmids showed a competitive disadvantage when cocultured with E. coli. These findings indicate that mcr-1 plasmids could spread more easily among E. coli than among K. pneumoniae isolates and that mcr-1 plasmid-carrying E. coli has a competitive advantage over K. pneumoniae, leading to E. coli being the main mcr-1 reservoir. IMPORTANCE As infections caused by multidrug-resistant "superbugs" are increasing globally, polymyxins are often the only viable therapeutic option. Alarmingly, the wide spread of the plasmid-mediated polymyxin resistance gene mcr-1 is restricting the clinical utility of this last-line treatment option. With this, there is an urgent need to investigate the factors contributing to the spread and persistence of mcr-1-bearing plasmids in the bacterial community. Our research highlights that the higher prevalence of mcr-1 in E. coli than in K. pneumoniae is attributed to the greater transferability and persistence of mcr-1-bearing plasmid in the former species. By gaining these important insights into the persistence of mcr-1 in different bacterial species, we will be able to formulate effective strategies to curb the spread of mcr-1 and prolong the clinical life span of polymyxins.

Epidemiology, risk factors and prognosis of ventilator-associated pneumonia during severe COVID-19: Multicenter observational study across 149 European Intensive Care Units

BACKGROUND

COVID-19 patients requiring mechanical ventilation are particularly at risk of developing ventilator-associated pneumonia (VAP). Risk factors and the prognostic impact of developing VAP during critical COVID-19 have not been fully documented.

METHODS

Patients invasively ventilated for at least 48 h from the prospective multicentre COVID-ICU database were included in the analyses. Cause-specific Cox regression models were used to determine factors associated with the occurrence of VAP. Cox-regression multivariable models were used to determine VAP prognosis. Risk factors and the prognostic impact of early vs. late VAP, and Pseudomonas-related vs. non-Pseudomonas-related VAP were also determined.

MAIN FINDINGS

3388 patients were analysed (63 [55-70] years, 75.8% males). VAP occurred in 1523/3388 (45.5%) patients after 7 [5-9] days of ventilation. Identified bacteria were mainly Enterobacteriaceae followed by Staphylococcus aureus and Pseudomonas aeruginosa. VAP risk factors were male gender (Hazard Ratio (HR) 1.26, 95% Confidence Interval [1.09-1.46]), concomitant bacterial pneumonia at ICU admission (HR 1.36 [1.10-1.67]), PaO₂/FiO₂ ratio at intubation (HR 0.99 [0.98-0.99] per 10 mmHg increase), neuromuscular-blocking agents (HR 0.89 [0.76-0.998]), and corticosteroids (HR 1.27 [1.09-1.47]). VAP was associated with 90-mortality (HR 1.34 [1.16-1.55]), predominantly due to late VAP (HR 1.51 [1.26-1.81]). The impact of Pseudomonas-related and non-Pseudomonas-related VAP on mortality was similar.

CONCLUSION

VAP affected almost half of mechanically ventilated COVID-19 patients. Several risk factors have been identified, among which modifiable risk factors deserve further investigation. VAP had a specific negative impact on 90-day mortality, particularly when it occurred between the end of the first week and the third week of ventilation.

Bacterial pneumonia associated with 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 an important culprit 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.

Disinfection efficacy of ozone on ESKAPE bacteria biofilms: Potential use in difficult-to-access medical devices

BACKGROUND

Medical devices can be reservoirs of multidrug-resistant bacteria that may be involved in the acquisition of infections since bacteria with the ability to form biofilms that are difficult to eradicate, mainly in mechanical ventilators. The aim of this work was to evaluate the efficacy of O₃ against biofilms of bacteria ESKAPE group through disinfection studies.

METHODS

The formation of biofilms of ESKAPE group bacteria was induced in vitro. O₃ was injected at different exposure times at a constant dose of 600 mg/h. The recovery of surviving bacteria after O₃ treatment was assessed by bacterial counts and biofilm disruption was analyzed. Finally, the viability and integrity of biofilms after O₃ treatment was determined by confocal laser scanning microscopy (CLSM).

RESULTS

O₃ showed bactericidal activity on biofilms from 12 min/7.68 ppm for A. baumannii and C. freundii. P. aeruginosa, K. pneumoniae and S. aureus were killed after 15 min/9.60 ppm. Correlation analyses showed inversely proportional relationships between the variables "disruption versus O₃". CLSM revealed that death was time-dependent of biofilms upon O₃ exposure. Orthogonal plane analysis showed that bacteria located in the outer region of the biofilms were the ones that initially suffered damage from O₃ exposure.

CONCLUSIONS

Our findings suggest that this method could be an alternative for the disinfection in mechanical ventilators colonized by bacteria biofilm forming.

The population-attributable fraction for time-to-event data

Background

Even though the population-attributable fraction (PAF) is a well-established metric, it is often incorrectly estimated or interpreted not only in clinical application, but also in statistical research articles. The risk of bias is especially high in more complex time-to-event data settings.

Methods

We explain how the PAF can be defined, identified and estimated in time-to-event settings with competing risks and time-dependent exposures. By using multi-state methodology and inverse probability weighting, we demonstrate how to reduce or completely avoid severe types of biases including competing risks bias, immortal time bias and confounding due to both baseline and time-varying patient characteristics.

Results

The method is exemplarily applied to a real data set. Moreover, we estimate the number of deaths that were attributable to ventilator-associated pneumonia in France in the year 2016. The example demonstrates how, under certain simplifying assumptions, PAF estimates can be extrapolated to a target population of interest.

Conclusions

Defining and estimating the PAF in advanced time-to-event settings within a framework that unifies causal and multi-state modelling enables to tackle common sources of bias and allows straightforward implementation with standard software packages.

Treatment of severe multi-drug resistant Pseudomonas aeruginosa infections

Pseudomonas aeruginosa is the microorganism most frequently involved in the main ICU-acquired infections, with special importance in ventilator associated pneumonia. Its importance lies, in addition to its high incidence in critically ill patients, in the severity of the infections it causes and in the difficulty of its antimicrobial treatment, directly related to the high percentage of resistance to antibiotics classically considered first-line. New active antibiotics have recently been developed against Pseudomonas aeruginosa, even against multi-drug resistant strains. This review analyzes both the differential characteristics of Pseudomonas aeruginosa infections and the new therapeutic options, focusing on multi-drug resistant Pseudomonas aeruginosa.

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

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

A novel prognostic model for predicting the mortality risk of patients with sepsis-related acute respiratory failure: a cohort study using the MIMIC-IV database

OBJECTIVES

Acute respiratory failure increases short-term mortality in sepsis patients. Hence, in this study, we aimed to develop a novel model for predicting the risk of hospital mortality in sepsis patients with acute respiratory failure.

METHODS

From the Medical Information Mart for Intensive Care (MIMIC)-IV database, we developed a matched cohort of adult sepsis patients with acute respiratory failure. After applying a multivariate COX regression analysis, we developed a nomogram based on the identified risk factors of mortality. Further, we evaluated the ability of the nomogram in predicting individual hospital death by the area under a receiver operating characteristic (ROC) curve.

RESULTS

A total of 663 sepsis patients with acute respiratory failure were included in this study. Systolic blood pressure, neutrophil percentage, white blood cells count, mechanical ventilation, partial pressure of oxygen < 60 mmHg, abdominal cavity infection, Klebsiella pneumoniae and Acinetobacter baumannii infection, and immunosuppressive diseases were the independent risk factors of mortality in sepsis patients with acute respiratory failure. The area under the ROC curve of the nomogram was 0.880 (95% CI: 0.851-0.908), which provided significantly higher discrimination compared to that of the simplified acute physiology score II [0.656 (95% CI: 0.612-0.701)].

CONCLUSION

The model shows a good performance in predicting the mortality risk of patients with sepsis-related acute respiratory failure. Hence, this model can be used to evaluate the short-term prognosis of critically ill patients with sepsis and acute respiratory failure.

A synthetic lipopeptide targeting top-priority multidrug-resistant Gram-negative pathogens

The emergence of multidrug-resistant (MDR) Gram-negative pathogens is an urgent global medical challenge. The old polymyxin lipopeptide antibiotics (polymyxin B and colistin) are often the only therapeutic option due to resistance to all other classes of antibiotics and the lean antibiotic drug development pipeline. However, polymyxin B and colistin suffer from major issues in safety (dose-limiting nephrotoxicity, acute toxicity), pharmacokinetics (poor exposure in the lungs) and efficacy (negligible activity against pulmonary infections) that have severely limited their clinical utility. Here we employ chemical biology to systematically optimize multiple non-conserved positions in the polymyxin scaffold, and successfully disconnect the therapeutic efficacy from the toxicity to develop a new synthetic lipopeptide, structurally and pharmacologically distinct from polymyxin B and colistin. This resulted in the clinical candidate F365 (QPX9003) with superior safety and efficacy against lung infections caused by top-priority MDR pathogens Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae.

Polymyxins are often the last therapeutic option for multidrug-resistant (MDR) bacteria, but have suboptimal safety and efficacy. Here the authors report the discovery and development of a synthetic lipopeptide with an improved safety and efficacy against top-priority MDR Gram-negative pathogens.

Defining Clinical and Microbiological Nonresponse in Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is a severe complication of mechanical ventilation, with mortality reduced most effectively by adequate early antibiotic treatment. The clinical and microbiologic response can be assessed easily from 72 hours after starting antibiotic treatment. Evidence of nonresponse is based on several factors: (1) lack of clinical improvement, (2) radiographic progression, (3) an impaired Sequential Organ Failure Assessment (SOFA) score, (4) no improvement by days 3 to 5 on the Clinical Pulmonary Infection Score (CPIS), (5) no decreased in biomarkers on day 3, and (6) isolation of a new pathogen on day 3. Among the clinical markers of treatment failure, physicians should consider no improvement in the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO₂/FiO₂), persistence of fever or hypothermia, persistence of purulent respiratory secretions, and new-onset septic shock or multiple-organ dysfunction syndrome. Microbiological isolation of a new pathogen on day 3 is also associated with higher mortality, but persistence of the original pathogen does not seem to be associated with a worse prognosis. The real impact of changes to treatment after diagnosing nonresponsive VAP is unknown. Physicians must evaluate whether treatments are adequate in terms of sensitivity, dose, and route. Pharmacokinetically and pharmacodynamically optimized doses are recommended in these patients. Clinical stabilization of comorbidities or underlying conditions may be of benefit.

"HAP and VAP after Guidelines"

Nosocomial pneumonia is associated with worsened prognosis when diagnosed in intensive care unit (ICU), ranging from 12 to 48% mortality. The incidence rate of ventilation-acquired pneumonia tends to decrease below 15/1,000 intubation-day. Still, international guidelines are heterogeneous about diagnostic criteria because of inaccuracy of available methods. New entities have thus emerged concerning lower respiratory tract infection, namely ventilation-acquired tracheobronchitis (VAT), or ICU-acquired pneumonia (ICUAP), eventually requiring invasive ventilation (v-ICUAP), according to the type of ventilation support. The potential discrepancy with non-invasive methods could finally lead to underdiagnosis in almost two-thirds of non-intubated patients. Delayed diagnostic could explain in part the 2-fold increase in mortality of penumonia when invasive ventilation is initiated. Here we discuss the rationale underlying this new classification.Many situations can lead to misdiagnosis, even more when the invasive mechanical ventilation is initiated. The chest radiography lacks sntivity and specificity for diagnosing pneumonia. The place of chest computed tomography and lung ultrasonography for routine diagnostic of new plumonary infiltrate remain to be evaluated.Microbiological methods used to confirm the diagnostic can be heterogeneous. The development of molecular diagnostic tools may improve the adequacy of antimicrobial therapies of ventilated patients with pneumonia, but we need to further assess its impact in non-ventilated pneumonia.In this review we introduce distinction between hospital-acquired pneumonia according to the localization in the hospital and the oxygenation/ventilation mode. A clarification of definition is the first step to develop more accurate diagnostic strategies and to improve the patients' prognosis.

The incidence and outcomes of healthcare-associated respiratory tract infections in non-ventilated neurocritical care patients: Results of a 10-year cohort study

The incidence of healthcare-associated respiratory tract infections in non-ventilated patients (NVA-HARTI) in neurosurgical intensive care units (ICUs) is unknown. The impact of NVA-HARTI on patient outcomes and differences between NVA-HARTI and ventilator-associated healthcare-associated respiratory tract infections (VA-HARTI) are poorly understood. Our objectives were to report the incidence, hospital length of stay (LOS), ICU LOS, and mortality in NVA-HARTI patients and compare these characteristics to VA-HARTI in neurocritical care patients. This cohort study was conducted in a neurosurgical ICU in Moscow. From 2011 to 2020, all patients with an ICU LOS > 48 h were included. A competing risk model was used for survival and risk analysis. A total of 3,937 ICU admissions were analyzed. NVA-HARTI vs VA-HARTI results were as follows: cumulative incidence 7.2 (95%CI: 6.4-8.0) vs 15.4 (95%CI: 14.2-16.5) per 100 ICU admissions; incidence rate 4.2 ± 2.0 vs 9.5 ± 3.0 per 1000 patient-days in the ICU; median LOS 32 [Q1Q3: 21, 48.5] vs 46 [Q1Q3: 28, 76.5] days; median ICU LOS 15 [Q1Q3: 10, 28.75] vs 26 [Q1Q3: 17, 43] days; mortality 12.3% (95%CI: 7.9-16.8) vs 16.7% (95%CI: 13.6-19.7). The incidence of VA-HARTI decreased over ten years while NVA-HARTI incidence did not change. VA-HARTI was an independent risk factor of death, OR 1.54 (1.11-2.14), while NVA-HARTI was not. Our findings suggest that NVA-HARTI in neurocritical care patients represents a significant healthcare burden with relatively high incidence and associated poor outcomes. Unlike VA-HARTI, the incidence of NVA-HARTI remained constant despite preventive measures. This suggests that extrapolating VA-HARTI research findings to NVA-HARTI should be avoided.

Postoperative care in ICU versus non-ICU after head and neck free-flap surgery: a systematic review and meta-analysis

OBJECTIVE

Admission to the intensive care unit (ICU) has long been considered as routine by most head and neck surgeons after microvascular free-flap transfer. This study aimed to answer the question 'Is there a difference in the flap survival and postoperative complications rates between admission to intensive care unit (ICU) versus Non-ICU following microvascular head and neck reconstructive surgery?'.

DESIGN

Systematic review, and meta-analysis.

METHODS

The PubMed, Embase, Scopus and Cochrane Library electronic databases were systematically searched (till April 2021) to identify the relevant studies. Studies that compared postoperative nursing of patients who underwent microvascular head and neck reconstructive surgery in ICU and non-ICU were included. The outcome variables were flap failure and length of hospital stay (LOS) and other complications. Weighted OR or mean differences with 95% CIs were calculated.

RESULTS

Eight studies involving a total of 2349 patients were included. No statistically significant differences were observed between ICU and non-ICU admitted patients regarding flap survival reported (fixed, risk ratio, 1.46; 95% CI 0.80 to 2.69, p=0.231, I²=0%), reoperation, readmission, respiratory failure, delirium and mortality (p>0.05). A significant increase in the postoperative pneumonia (p=0.018) and sepsis (p=0.033) was observed in patients admitted to ICU compared with non-ICU setting.

CONCLUSION

This meta-analysis showed that an immediate postoperative nursing in the ICU after head and neck microvascular reconstructive surgery did not reduce the incidence of flap failure or complications rate. Limiting the routine ICU admission to the carefully selected patients may result in a reduction in the incidence of postoperative pneumonia, sepsis, LOS and total hospital charge.

Oral care for intensive care unit patients without mechanical ventilation: protocol for a systematic review and meta-analysis

BACKGROUND

Infection is a common problem and a major cause of morbidity and mortality for patients in intensive care units (ICUs). According to published meta-analyses, oral care has been found to reduce the risk of nosocomial pneumonia, and has been recommended to improve the oral environment for patients in ICUs. However, relatively little information is available about the effects of oral care in patients without ventilatory support in ICUs. Therefore, this review proposes to evaluate the effectiveness of oral care in preventing pneumonia in non-ventilated ICU patients.

METHODS

Eight databases will be searched for relevant literature, including four Chinese and four English online databases, from their inception to the protocol publication date. Records obtained will be managed and screened via Endnote X7. All literature will be selected following pre-established inclusion criteria by two independent review authors to obtain quality trials. The quality of the included records will be evaluated according to the "risk of bias table", recommended by the Cochrane Handbook for Systematic Reviews of Interventions. All the data will be extracted by one author and checked by another. If there is any disagreement, a final agreement will be reached with a third reviewer via consultation. If there are missing data, the original authors will be emailed to ask for it. If enough data were collected, the data synthesis will be performed using Review Manager (RevMan5.3). Both a random effect model and a fixed effect model will be undertaken. A Bayesian meta-analysis will also be performed to estimate the magnitude of the heterogeneity variance and comparing it with the distribution using the WinBUGS software. Otherwise, the results will be reported narratively. The sources of heterogeneity will be determined using meta-regression and subgroup analysis if there is significant heterogeneity. A funnel plot will be used to assess publication bias if there are enough records included. The Cochrane Handbook for Systematic Reviews of Interventions will be followed throughout the system evaluation process.

CONCLUSION

This review will provide evidence of oral care for intensive care unit patients without mechanical ventilation to prevent nosocomial pneumonia.

TRIAL REGISTRATION

PROSPERO Research registration identifying number: CRD42020146932.

Epidemiology and Risk Factors of Healthcare-Associated Infections in Critically Ill Patients in a Tertiary Care Teaching Hospital in Nepal: A Prospective Cohort Study

Background:

Healthcare-associated infection (HAI) is an important public health problem, particularly in intensive care units (ICUs). We aimed to examine the epidemiology and risk factors of HAIs in our ICUs and study their microbiological profile.

Methods:

We evaluated 100 consecutive patients in 3 medical and surgical ICUs of a tertiary care teaching hospital daily starting in January 2016 using the Centers for Disease Control and Prevention definitions and methods. We determined the incidence and sites of HAIs, identified the causative microorganism, and studied their antibiotic sensitivity profiles. We investigated risk factors for the development of an HAI using a multiple logistic regression model.

Results:

Of 300 patients, 129 patients (43%) developed HAIs (55.96 HAI events per 1000 ICU-days). Pneumonia was the most common type of HAI (57, 41%). Escherichia coli was the most frequently isolated microorganism (20, 29%) and 74% of the pathogens isolated were multi-drug resistant. The presence of an invasive device (Odds Ratio, 4.29; 95% Confidence Interval, 2.52-7.51) and use of sedation (Odds Ratio, 2.24; 95% Confidence Interval, 1.31-3.87) were the statistically significant risk factors for HAIs.

Conclusions:

We found a high incidence of HAIs in our ICUs and a high burden of multidrug-resistant microorganisms highlighting the importance of infection control and antibiotic stewardship.

Rapid diagnostic tests in the management of pneumonia

INTRODUCTION

Pneumonia is one of the main causes of mortality associated with infectious diseases worldwide. Several challenges have been identified in the management of patients with pneumonia, ranging from accurate and cost-effective microbiological investigations, prompt and adequate therapeutic management, and optimal treatment duration.

AREAS COVERED

In this review, an updated summary on the current management of pneumonia patients is provided and the epidemiological issues of infectious respiratory diseases, which in the current pandemic situation are of particular concern, are addressed. The clinical and microbiological approaches to pneumonia diagnosis are reviewed, including discussion about the new molecular assays pointing out both their strengths and limitations. Finally, the current recommendations about antibiotic treatment are examined and discussed depending on the epidemiological contexts, including those with high prevalence of multidrug-resistant bacteria.

EXPERT OPINION

We claim that rapid diagnostic tests, if well-positioned in the diagnostic workflow and reserved for the subset of patients who could most benefit from these technologies, may represent an interesting and feasible tool to optimize timing of targeted treatments especially in terms of early de-escalation or discontinuation of antibiotic therapy.

Extracorporeal CO2 removal in acute exacerbation of COPD unresponsive to non-invasive ventilation

Background

The gold-standard treatment for acute exacerbation of chronic obstructive pulmonary disease (ae-COPD) is non-invasive ventilation (NIV). However, NIV failures may be observed, and invasive mechanical ventilation (IMV) is required. Extracorporeal CO₂ removal (ECCO₂R) devices can be an alternative to intubation. The aim of the study was to assess ECCO₂R effectiveness and safety.

Methods

Patients with consecutive ae-COPD who experienced NIV failure were retrospectively assessed over two periods of time: before and after ECCO₂R device implementation in our ICU in 2015 (Xenios AG).

Results

Both groups (ECCO₂R: n=26, control group: n=25) were comparable at baseline, except for BMI, which was significantly higher in the ECCO₂R group (30 kg/m² vs 25 kg/m²). pH and PaCO₂ significantly improved in both groups. The mean time on ECCO₂R was 5.4 days versus 27 days for IMV in the control group. Four patients required IMV in the ECCO₂R group, of whom three received IMV after ECCO₂R weaning. Seven major bleeding events were observed with ECCO₂R, but only three led to premature discontinuation of ECCO₂R. Eight cases of ventilator-associated pneumonia were observed in the control group. Mean time spent in the ICU and mean hospital stay in the ECCO₂R and control groups were, respectively, 18 vs 30 days, 29 vs 49 days, and the 90-day mortality rates were 15% vs 28%.

Conclusions

ECCO₂R was associated with significant improvement of pH and PaCO₂ in patients with ae-COPD failing NIV therapy. It also led to avoiding intubation in 85% of cases, with low complication rates.

Trial registration number

ClinicalTrials.gov, NCT04882410. Date of registration 12 May 2021, retrospectively registered.

https://www.clinicaltrials.gov/ct2/show/NCT04882410.

Management of pneumonia in critically ill patients

Severe pneumonia is associated with high mortality (short and long term), as well as pulmonary and extrapulmonary complications. Appropriate diagnosis and early initiation of adequate antimicrobial treatment for severe pneumonia are crucial in improving survival among critically ill patients. Identifying the underlying causative pathogen is also critical for antimicrobial stewardship. However, establishing an etiological diagnosis is challenging in most patients, especially in those with chronic underlying disease; those who received previous antibiotic treatment; and those treated with mechanical ventilation. Furthermore, as antimicrobial therapy must be empiric, national and international guidelines recommend initial antimicrobial treatment according to the location's epidemiology; for patients admitted to the intensive care unit, specific recommendations on disease management are available. Adherence to pneumonia guidelines is associated with better outcomes in severe pneumonia. Yet, the continuing and necessary research on severe pneumonia is expansive, inviting different perspectives on host immunological responses, assessment of illness severity, microbial causes, risk factors for multidrug resistant pathogens, diagnostic tests, and therapeutic options.

Molecular diagnostic methods for pneumonia: how can they be applied in practice?

PURPOSE OF REVIEW

Pneumonia represents a major burden in clinical practice. A rapid etiological diagnosis is critical for optimizing the antibiotic use. Owing to the variety of possible pathogens and the time needed for bacterial cultures or usual polymerase chain reaction (PCR) assays, timely and precise diagnosis is a huge challenge. Several new rapid multiplex assays have been developed in the last decade to resolve these issues. This review aims to provide an overview of recent evidence on improvements and limitations of new rapid molecular assays for pneumonia.

RECENT FINDINGS

Several rapid multiplex-PCR assays are commercially available for upper or lower respiratory tract samples, allowing detection of a wide range of respiratory viruses, bacteria, and, in some cases, of several antibiotic resistance genes. Clinical evaluations demonstrated their good correlation with gold-standard assays but their lack of exhaustiveness, especially for hospital-acquired pneumonia. Studies that evaluated their potential benefits on antibiotic use suffered from important weaknesses with conflicting and limited results.

SUMMARY

New molecular assays may enable improvements in patient management and antibiotic use. Available studies highlight several benefits and the strong interrelations needed between microbiologists and physicians for their implementation and interpretation according to the clinical and epidemiological context.

Association between mortality and highly antimicrobial-resistant bacteria in intensive care unit-acquired pneumonia

Data on the relationship between antimicrobial resistance and mortality remain scarce, and this relationship needs to be investigated in intensive care units (ICUs). The aim of this study was to compare the ICU mortality rates between patients with ICU-acquired pneumonia due to highly antimicrobial-resistant (HAMR) bacteria and those with ICU-acquired pneumonia due to non-HAMR bacteria. We conducted a multicenter, retrospective cohort study using the French National Surveillance Network for Healthcare Associated Infection in ICUs ("REA-Raisin") database, gathering data from 200 ICUs from January 2007 to December 2016. We assessed all adult patients who were hospitalized for at least 48 h and presented with ICU-acquired pneumonia caused by S. aureus, Enterobacteriaceae, P. aeruginosa, or A. baumannii. The association between pneumonia caused by HAMR bacteria and ICU mortality was analyzed using the whole sample and using a 1:2 matched sample. Among the 18,497 patients with at least one documented case of ICU-acquired pneumonia caused by S. aureus, Enterobacteriaceae, P. aeruginosa, or A. baumannii, 3081 (16.4%) had HAMR bacteria. The HAMR group was associated with increased ICU mortality (40.3% vs. 30%, odds ratio (OR) 95%, CI 1.57 [1.45-1.70], P < 0.001). This association was confirmed in the matched sample (3006 HAMR and 5640 non-HAMR, OR 95%, CI 1.39 [1.27-1.52], P < 0.001) and after adjusting for confounding factors (OR ranged from 1.34 to 1.39, all P < 0.001). Our findings suggest that ICU-acquired pneumonia due to HAMR bacteria is associated with an increased ICU mortality rate, ICU length of stay, and mechanical ventilation duration.

Oral Care in Critically Ill Patients Requiring Noninvasive Ventilation: An Evidence-Based Review

TOPIC

Hospital-acquired pneumonia commonly develops after 48 hours of hospitalization and can be divided into non-ventilator-acquired and ventilator-acquired pneumonia. Prevention of non-ventilator-acquired pneumonia requires a multimodal approach. Implementation of oral care bundles can reduce the incidence of ventilator-acquired pneumonia, but the literature on oral care in other populations is limited.

CLINICAL RELEVANCE

Use of noninvasive ventilation is increasing owing to positive outcomes. The incidence of non-ventilator-acquired pneumonia is higher in patients receiving noninvasive ventilation than in the general hospitalized population but remains lower than that of ventilator-acquired pneumonia. Non-ventilator-acquired pneumonia increases mortality risk and hospital length of stay.

PURPOSE

To familiarize nurses with the evidence regarding oral care in critically ill patients requiring noninvasive ventilation.

CONTENT COVERED

No standard of oral care exists for patients requiring noninvasive ventilation owing to variation in study findings, definitions, and methods. Oral care decreases the risk of hospital-acquired pneumonia and improves comfort. Nurses perform oral care less often for nonintubated patients, as it is perceived as primarily a comfort measure. The potential risks of oral care for patients receiving noninvasive ventilation have not been explored. Further research is warranted before this practice can be fully implemented.

CONCLUSION

Oral care is a common preventive measure for non-ventilator-acquired pneumonia and may improve comfort. Adherence to oral care is lower for patients not receiving mechanical ventilation. Further research is needed to identify a standard of care for oral hygiene for patients receiving noninvasive ventilation and assess the risk of adverse events.

The effect of ventilator-associated pneumonia on the prognosis of intensive care unit patients within 90 days and 180 days

BACKGROUND

Mechanical ventilation (MV) is often applied in critically ill patients in intensive care unit (ICU) to protect the airway from aspiration, and supplement more oxygen. MV may result in ventilator-associated pneumonia (VAP) in ICU patients. This study was to estimate the 90-day and 180-day mortalities of ICU patients with VAP, and to explore the influence of VAP on the outcomes of ICU patients.

METHODS

Totally, 8182 patients who aged ≥18 years and received mechanical ventilation (MV) in ICU from Medical Information Mart for Intensive Care III (MIMIC III) database were involved in this study. All subjects were divided into the VAP group (n = 537) and the non-VAP group (n = 7626) based on the occurrence of VAP. Clinical data of all participants were collected. The effect of VAP on the prognosis of ICU patients was explored by binary logistic regression analysis.

RESULTS

The results delineated that the 90-day mortality of VAP patients in ICU was 33.33% and 180-day mortality was 37.62%. The 90-day and 180-day mortality rates were higher in the VAP group than in the non-VAP group. After adjusting the confounders including age, ethnicity, heart failure, septicemia, simplified acute physiology score II (SAPSII) score, sequential organ failure assessment (SOFA) score, serum lactate, white blood cell (WBC), length of ICU stay, length of hospital stay, length of ventilation, antibiotic treatment, Pseudomonas aeruginosa (P.aeruginosa), methicillin-resistant Staphylococcus aureus (MRSA), other pathogens, the risk of 90-day and 180-day mortalities in VAP patients were 1.465 times (OR = 1.465, 95%CI: 1.188-1.807, P < 0.001) and 1.635 times (OR = 1.635, 95%CI: 1.333-2.005, P < 0.001) higher than those in non-VAP patients, respectively.

CONCLUSIONS

Our study revealed that ICU patients with VAP had poorer prognosis than those without VAP. The results of this study might offer a deeper insight into preventing the occurrence of VAP.

Characteristics, management, and clinical outcomes of patients with hospital-acquired and ventilator-associated pneumonia: a multicenter cohort study in Korea

Background

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are significant public health issues in the world, but the epidemiological data pertaining to HAP/VAP is limited in Korea. The objective of this study was to investigate the characteristics, management, and clinical outcomes of HAP/VAP in Korea.

Methods

This study is a multicenter retrospective cohort study. In total, 206,372 adult patients, who were hospitalized at one of the 13 participating tertiary hospitals in Korea, were screened for eligibility during the six-month study period. Among them, we included patients who were diagnosed with HAP/VAP based on the Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) definition for HAP/VAP.

Results

Using the IDSA/ATS diagnostic criteria, 526 patients were identified as HAP/VAP patients. Among them, 27.9% were diagnosed at the intensive care unit (ICU). The cohort of patients had a median age of 71.0 (range from 62.0 to 79.0) years. Most of the patients had a high risk of aspiration (63.3%). The pathogen involved was identified in 211 patients (40.1%). Furthermore, multidrug resistant (MDR) pathogens were isolated in 138 patients; the most common MDR pathogen was Acinetobacter baumannii. During hospitalization, 107 patients with HAP (28.2%) had to be admitted to the ICU for additional care. The hospital mortality rate was 28.1% in the cohort of this study. Among the 378 patients who survived, 54.2% were discharged and sent back home, while 45.8% were transferred to other hospitals or facilities.

Conclusion

This study found that the prevalence of HAP/VAP in adult hospitalized patients in Korea was 2.54/1,000 patients. In tertiary hospitals in Korea, patients with HAP/VAP were elderly and had a risk of aspiration, so they were often referred to step-down centers.

Pneumonia

Pneumonia is a common acute respiratory infection that affects the alveoli and distal airways; it is a major health problem and associated with high morbidity and short-term and long-term mortality in all age groups worldwide. Pneumonia is broadly divided into community-acquired pneumonia or hospital-acquired pneumonia. A large variety of microorganisms can cause pneumonia, including bacteria, respiratory viruses and fungi, and there are great geographical variations in their prevalence. Pneumonia occurs more commonly in susceptible individuals, including children of <5 years of age and older adults with prior chronic conditions. Development of the disease largely depends on the host immune response, with pathogen characteristics having a less prominent role. Individuals with pneumonia often present with respiratory and systemic symptoms, and diagnosis is based on both clinical presentation and radiological findings. It is crucial to identify the causative pathogens, as delayed and inadequate antimicrobial therapy can lead to poor outcomes. New antibiotic and non-antibiotic therapies, in addition to rapid and accurate diagnostic tests that can detect pathogens and antibiotic resistance will improve the management of pneumonia.

Surveillance for Healthcare-Associated Infections: Hospital-Onset Adult Sepsis Events versus Current Reportable Conditions

BACKGROUND

U.S. hospitals are required by CMS to publicly report CLABSI, CAUTI, C.diffficile, MRSA bacteremia, and selected SSIs for benchmarking and pay-for-performance programs. It is unclear, however, to what extent these conditions capture the full breadth of serious healthcare-associated infections (HAIs). CDC's hospital-onset Adult Sepsis Event (HO-ASE) definition could facilitate more comprehensive and efficient surveillance for serious HAIs, but the overlap between HO-ASE and currently reportable HAIs is unknown.

METHODS

We retrospectively assessed the overlap between HO-ASEs and reportable HAIs among adults hospitalized between June 2015-June 2018 in 3 hospitals. Medical record reviews were conducted for 110 randomly selected HO-ASE cases to determine clinical correlates.

RESULTS

Amongst 282,441 hospitalized patients, 2,301 (0.8%) met HO-ASE criteria and 1,260 (0.4%) had reportable HAIs. In-hospital mortality rates were higher with HO-ASEs than reportable HAIs (28.6% vs 12.9%). Mortality rates for HO-ASE missed by reportable HAIs were substantially higher than mortality rates for reportable HAIs missed by HO-ASE (28.1% vs 6.3%). Reportable HAIs were only present in 334/2,301 (14.5%) HO-ASEs, most commonly CLABSIs (6.0% of HO-ASEs), C.difficile (5.0%), and CAUTI (3.0%). On medical record review, most HO-ASEs were caused by pneumonia (39.1%, of which only 34.9% were ventilator-associated), bloodstream infections (17.4%, of which only 10.5% were central line-associated), non-C.difficile intra-abdominal infections (14.5%), urinary infections (7.3%, of which 87.5% were catheter-associated), and skin/soft tissue infections (6.4%).

CONCLUSIONS

CDC's HO-ASE definition detects many serious nosocomial infections missed by currently reportable HAIs. HO-ASE surveillance could increase the efficiency and clinical significance of surveillance while identifying new targets for prevention.

Incidence and impact of hospital-acquired pneumonia: a Portuguese nationwide four-year study

This article presents the incidence of hospital-acquired pneumonia (HAP) in Portugal during a four-year period (2014-2017). Data were retrieved from the 100 Portuguese hospital diagnosis discharge database for adult patients and included gender, age, chronic comorbidities, mortality and hospital length of stay. There were 28,632 episodes of HAP, an incidence of 0.95 per 100 admissions. HAP patients had both a prolonged hospital length of stay (mean 26.4 days) and high mortality (33.6%). Most episodes occurred in patients aged ≥65 years and in males (76.1% and 61.7%, respectively). Invasive ventilation was required in 18.8%.

Impact of rapid multiplex PCR on management of antibiotic therapy in COVID-19-positive patients hospitalized in intensive care unit

Because the diagnosis of co/superinfection in COVID-19 patients is challenging, empirical antibiotic therapy is frequently initiated until microbiological analysis results. We evaluated the performance and the impact of the BioFire® FilmArray® Pneumonia plus Panel on 112 respiratory samples from 67 COVID-19 ICU patients suspected of co/superinfections. Globally, the sensitivity and specificity of the test were 89.3% and 99.1%, respectively. Positive tests led to antibiotic initiation or adaptation in 15% of episodes and de-escalation in 4%. When negative, 28% of episodes remained antibiotic-free (14% no initiation, 14% withdrawal). Rapid multiplex PCRs can help to improve antibiotic stewardship by administering appropriate antibiotics earlier and avoiding unnecessary prescriptions.

Healthcare Resource Utilization of Ceftolozane/Tazobactam Versus Meropenem for Ventilated Nosocomial Pneumonia from the Randomized, Controlled, Double-Blind ASPECT-NP Trial

Introduction

Hospital-acquired and ventilator-associated bacterial pneumonia (HABP and VABP) are associated with significant healthcare resource utilization (HCRU). This a priori, exploratory, secondary analysis from the ASPECT-NP clinical trial evaluated resource utilization among patients with ventilated HABP (vHABP)/VABP treated with ceftolozane/tazobactam or meropenem.

Methods

This analysis used data from the randomized, double-blind, noninferiority phase 3 ASPECT-NP trial of patients with vHABP/VABP randomized to receive ceftolozane/tazobactam 3 g (ceftolozane 2 g/tazobactam 1 g) or meropenem 1 g for 8–14 days. Day 28 outcomes included hospital length of stay (LOS), intensive care unit (ICU) LOS, and time to mechanical ventilation extubation in the microbiological intention-to-treat (mITT) population and in an HCRU population. The HCRU population, a subset of patients from the mITT population that were alive at day 28, was used to remove resource use bias influenced by mortality rates.

Results

Ceftolozane/tazobactam-treated versus meropenem-treated patients, respectively, had fewer deaths (20.1% vs. 25.5%), fewer hospital discharges (30.7% vs. 32.4%), and higher ICU discharges (60.0% vs. 58.3%) and extubations (51.9% vs. 48.2%) by day 28. In the HCRU population, adjusted LOS differences (95% confidence intervals) for ceftolozane/tazobactam compared with meropenem were 0.1 (− 1.4 to 1.6) hospitalization days, − 1.4 (− 2.9 to 0.2) ICU days, and − 0.9 (− 2.4 to 0.7) mechanical ventilation days. Patterns were similar among the VABP and Pseudomonas aeruginosa subgroups.

Conclusion

Similar 28-day resource utilization outcomes were observed between ceftolozane/tazobactam and meropenem in the mITT population of patients from ASPECT-NP with vHABP/VABP due to gram-negative pathogens. ASPECT-NP was not powered to detect differences in resource utilization outcomes between treatment groups; however, numerical differences in ICU LOS and duration of mechanical ventilation were noted. Further study is needed to assess resource utilization in the real-world practice setting, especially among patients excluded from ASPECT-NP, including those with resistant P. aeruginosa infections.

Trial Registrations

ClinicalTrials.gov: NCT02070757, registered February 25, 2014; EudraCT: 2012-002862-11.

Electronic supplementary material

The online version of this article (10.1007/s40121-020-00343-0) contains supplementary material, which is available to authorized users.

Infectious Complications in Severe Acute Pancreatitis: Pathogens, Drug Resistance, and Status of Nosocomial Infection in a University-Affiliated Teaching Hospital

BACKGROUND

Secondary infection is an important factor affecting mortality and quality of life in patients with severe acute pancreatitis. The characteristics of secondary infection, which are well known to clinicians, need to be re-examined in detail, and their understanding among clinicians needs to be updated accordingly.

AIM

This study aims to investigate the characteristics and drug resistance of pathogens causing severe acute pancreatitis (SAP) secondary infection, to objectively present infection situation, and to provide reference for improved clinical management.

METHODS

A retrospective analysis was performed on 55 consecutive patients with SAP who developed secondary infection with an accurate evidence of bacterial/fungal culture from 2016 to 2018. The statistics included the spectrum and distribution of pathogens, the drug resistance of main pathogens, and associations between multiple infectious parameters and mortality.

RESULTS

A total of 181 strains of pathogens were isolated from (peri)pancreas; bloodstream; and respiratory, urinary, and biliary systems in 55 patients. The strains included 98 g-negative bacteria, 58 g-positive bacteria, and 25 fungi. Bloodstream infection (36.5%) was the most frequent infectious complication, followed by (peri)pancreatic infection (32.0%). Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Stenotrophomonas maltophilia were predominant among gram-negative bacteria. Gram-positive bacterial infections were mainly caused by Enterococcus faecium and Staphylococcus spp. Fungal infections were predominantly caused by Candida spp. The drug resistance of pathogens causing SAP secondary infection was generally higher than the surveillance level. Patients in the death group were older (55 ± 13 years vs. 46 ± 14 years; p = 0.039) and had longer intensive care unit (ICU) stay (14 vs. 8; p = 0.026) than those in the survival group. A. baumannii infection (68.4% vs. 33%; p = 0.013), number of pathogens ≥ 4 (10 vs. 6; p = 0.005), pancreatic infection (14 vs. 15, p = 0.024), and urinary infection (8 vs. 5; p = 0.019) were significantly associated with mortality.

CONCLUSION

Gram-negative bacteria are the main pathogens causing SAP secondary infection, in which nosocomial infections play a major role. The drug resistance profile of gram-negative bacteria is seriously threatening, and the commonly used antibiotics in SAP are gradually losing their effectiveness. Much attention should be paid to the rational use of antibiotics, and strategies should be established for infection prevention in SAP.

Update of the treatment of nosocomial pneumonia in the ICU

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

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

BACKGROUND

Early appropriate antibiotic therapy reduces morbidity and mortality of severe pneumonia. However, the emergence of bacterial resistance requires the earliest use of antibiotics with the narrowest possible spectrum. The Unyvero Hospitalized Pneumonia (HPN, Curetis) test is a multiplex PCR (M-PCR) system detecting 21 bacteria and 19 resistance genes on respiratory samples within 5 h. We assessed the performance and the potential impact of the M-PCR on the antibiotic therapy of ICU patients.

METHODS

In this prospective study, we performed a M-PCR on bronchoalveolar lavage (BAL) or plugged telescoping catheter (PTC) samples of patients with ventilated HAP or VAP with Gram-negative bacilli or clustered Gram-positive cocci. This study was conducted in 3 ICUs in a French academic hospital: the medical and infectious diseases ICU, the surgical ICU, and the cardio-surgical ICU. A multidisciplinary expert panel simulated the antibiotic changes they would have made if the M-PCR results had been available.

RESULTS

We analyzed 95 clinical samples of ventilated HAP or VAP (72 BAL and 23 PTC) from 85 patients (62 males, median age 64 years). The median turnaround time of the M-PCR was 4.6 h (IQR 4.4-5). A total of 90/112 bacteria were detected by the M-PCR system with a global sensitivity of 80% (95% CI, 73-88%) and specificity of 99% (95% CI 99-100). The sensitivity was better for Gram-negative bacteria (90%) than for Gram-positive cocci (62%) (p = 0.005). Moreover, 5/8 extended-spectrum beta-lactamases (CTX-M gene) and 4/4 carbapenemases genes (3 NDM, one oxa-48) were detected. The M-PCR could have led to the earlier initiation of an effective antibiotic in 20/95 patients (21%) and to early de-escalation in 37 patients (39%) but could also have led to one (1%) inadequate antimicrobial therapy. Among 17 empiric antibiotic treatments with carbapenems, 10 could have been de-escalated in the following hours according to the M-PCR results. The M-PCR also led to 2 unexpected diagnosis of severe legionellosis confirmed by culture methods.

CONCLUSIONS

Our results suggest that the use of a M-PCR system for respiratory samples of patients with VAP and ventilated HAP could improve empirical antimicrobial therapy and reduce the use of broad-spectrum antibiotics.

Semi-quantitative cultures of throat and rectal swabs are efficient tests to predict ESBL-Enterobacterales ventilator-associated pneumonia in mechanically ventilated ESBL carriers

PURPOSE

In ICU patients with carriage of extended spectrum beta-lactamase producing Enterobacterales (ESBL-E) and suspected Gram-negative bacilli ventilator-associated pneumonia (GNB-VAP), the quantification of the rectal and throat ESBL-E carriage might predict the ESBL-E involvement in GNB-VAP. Our aim was to evaluate whether a semi-quantitative assessment of rectal/throat ESBL-E carriage can predict ESBL-E-associated VAP in medical ICU patients.

METHODS

From May 2014 to May 2017, all ESBL-E carriers had a semi-quantitative assessment of ESBL-E density in swabs cultures. For those who developed GNB-VAP (diagnosed using bronchoalveolar lavage or plugged telescopic catheter with significant quantitative culture), the last positive swab collected at least 48 h before GNB-VAP onset was selected. Clinical data were extracted from a prospectively collected database.

RESULTS

Among 365 ESBL-E carriers, 82 developed 107 episodes of GNB-VAP (ESBL-E VAP, n = 50; and non-ESBL-E GNB-VAP, n = 57) after 13 days of mechanical ventilation in median. Antimicrobials use before VAP onset was similar between groups. The last swabs were collected 5 days in median before VAP onset. ESBL-E. coli carriers developed ESBL-E VAP less frequently (n = 13, 34%) than others (n = 32, 67.3%, p < .01). Throat swab positivity (39 (78%) vs. 12 (23%), p < .01) was more frequent for ESBL-E VAP. ESBL-E VAP was associated with significantly higher ESBL-E density in rectal swabs. In multivariate models, non-E. coli ESBL-E carriage and rectal ESBL-E carriage density, or throat carriage, remained associated with ESBL-E VAP.

CONCLUSION

In carriers of ESBL-E other than E. coli, ESBL-E throat carriage or a high-density ESBL-E rectal carriage are risk factors of ESBL-E VAP in case of GNB-VAP.