Bacterial Ventilator-Associated Pneumonia in COVID-19 Patients: Data from the Second and Third Waves of the Pandemic

Obesity Inhibits Alveolar Macrophage Responses to Pseudomonas aeruginosa Pneumonia via Upregulation of Prostaglandin E2 in Male, but Not Female, Mice

Obesity is associated with increased morbidity and mortality during bacterial pneumonia. Cyclooxygenase-2 (COX-2) and PGE2 have been shown to be upregulated in patients who are obese. In this study, we investigated the role of obesity and PGE2 in bacterial pneumonia and how inhibition of PGE2 improves antibacterial functions of macrophages. C57BL/6J male and female mice were fed either a normal diet (ND) or high-fat diet (HFD) for 16 wk. After this time, animals were infected with Pseudomonas aeruginosa in the lung. In uninfected animals, alveolar macrophages were extracted for either RNA analysis or to be cultured ex vivo for functional analysis. HFD resulted in changes in immune cell numbers in both noninfected and infected animals. HFD animals had increased bacterial burden compared with ND animals; however, male HFD animals had higher bacterial burden compared with HFD females. Alveolar macrophages from HFD males had decreased ability to phagocytize and kill bacteria and were shown to have increased cyclooxygenase-2 and PGE2. Treating male, but not female, alveolar macrophages with PGE2 leads to increases in cAMP and decreased bacterial phagocytosis. Treatment with lumiracoxib-conjugated nanocarriers targeting alveolar macrophages improves bacterial phagocytosis and clearance in both ND and HFD male animals. Our study highlights that obesity leads to worse morbidity during bacterial pneumonia in male mice because of elevated PGE2. In addition, we uncover a sex difference in both obesity and infection, because females produce high basal PGE2 but because of a failure to signal via cAMP do not display impaired phagocytosis.

Intravenous fosfomycin for treatment of severe infections caused by carbapenem-resistant Acinetobacter baumannii: A multi-centre clinical experience

BACKGROUND

Severe infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) have been reported increasingly over the past few years. Many in-vivo and in-vitro studies have suggested a possible role of intravenous fosfomycin for the treatment of CRAB infections.

METHODS

This multi-centre, retrospective study included patients treated with intravenous fosfomycin for severe infections caused by CRAB admitted consecutively to four hospitals in Italy from December 2017 to December 2022. The primary goal of the study was to evaluate the risk factors associated with 30-day mortality in the study population. A propensity score matched analysis was added to the model.

RESULTS

One hundred and two patients with severe infections caused by CRAB treated with an intravenous fosfomycin-containing regimen were enrolled in this study. Ventilator-associated pneumonia (VAP) was diagnosed in 59% of patients, primary bacteraemia in 22% of patients, and central-venous-catheter-related infection in 16% of patients. All patients were treated with a regimen containing intravenous fosfomycin, mainly in combination with cefiderocol (n=54), colistin (n=48) or ampicillin/sulbactam (n=18). Forty-eight (47%) patients died within 30 days. Fifty-eight (57%) patients experienced clinical therapeutic failure. Cox regression analysis showed that diabetes, primary bacteraemia and a colistin-containing regimen were independently associated with 30-day mortality, whereas adequate source control of infection, early 24-h active in-vitro therapy, and a cefiderocol-containing regimen were associated with survival. A colistin-based regimen, A. baumannii colonization and primary bacteraemia were independently associated with clinical failure. Conversely, adequate source control of infection, a cefiderocol-containing regimen, and early 24-h active in-vitro therapy were associated with clinical success.

CONCLUSIONS

Different antibiotic regimens containing fosfomycin in combination can be used for treatment of severe infections caused by CRAB.

Tau and Aβ42 in lavage fluid of pneumonia patients are associated with end-organ dysfunction: A prospective exploratory study

BACKGROUND

Bacterial pneumonia and sepsis are both common causes of end-organ dysfunction, especially in immunocompromised and critically ill patients. Pre-clinical data demonstrate that bacterial pneumonia and sepsis elicit the production of cytotoxic tau and amyloids from pulmonary endothelial cells, which cause lung and brain injury in naïve animal subjects, independent of the primary infection. The contribution of infection-elicited cytotoxic tau and amyloids to end-organ dysfunction has not been examined in the clinical setting. We hypothesized that cytotoxic tau and amyloids are present in the bronchoalveolar lavage fluid of critically ill patients with bacterial pneumonia and that these tau/amyloids are associated with end-organ dysfunction.

METHODS

Bacterial culture-positive and culture-negative mechanically ventilated patients were recruited into a prospective, exploratory observational study. Levels of tau and Aβ42 in, and cytotoxicity of, the bronchoalveolar lavage fluid were measured. Cytotoxic tau and amyloid concentrations were examined in comparison with patient clinical characteristics, including measures of end-organ dysfunction.

RESULTS

Tau and Aβ42 were increased in culture-positive patients (n = 49) compared to culture-negative patients (n = 50), independent of the causative bacterial organism. The mean age of patients was 52.1 ± 16.72 years old in the culture-positive group and 52.78 ± 18.18 years old in the culture-negative group. Males comprised 65.3% of the culture-positive group and 56% of the culture-negative group. Caucasian culture-positive patients had increased tau, boiled tau, and Aβ42 compared to both Caucasian and minority culture-negative patients. The increase in cytotoxins was most evident in males of all ages, and their presence was associated with end-organ dysfunction.

CONCLUSIONS

Bacterial infection promotes the generation of cytotoxic tau and Aβ42 within the lung, and these cytotoxins contribute to end-organ dysfunction among critically ill patients. This work illuminates an unappreciated mechanism of injury in critical illness.

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.

Typing of Candida spp. from Colonized COVID-19 Patients Reveal Virulent Genetic Backgrounds and Clonal Dispersion

Advances in the knowledge of the pathogenesis of SARS-CoV-2 allowed the survival of COVID-19 patients in intensive care units. However, due to the clinical characteristics of severe patients, they resulted in the appearance of colonization events. Therefore, we speculate that strains of Candida spp. isolated from COVID-19 patients have virulent genetic and phenotypic backgrounds involved in clinical worsening of patients. The aim of this work was to virutype Candida spp. strains isolated from colonized COVID-19 patients, analyze their genomic diversity, and establish clonal dispersion in care areas. The virulent potential of Candida spp. strains isolated from colonized COVID-19 patients was determined through adhesion tests and the search for genes involved with adherence and invasion. Clonal association was done by analysis of intergenic spacer regions. Six species of Candida were involved as colonizing pathogens in COVID-19 patients. The genotype analysis revealed the presence of adherent and invasive backgrounds. The distribution of clones was identified in the COVID-19 care areas, where C. albicans was the predominant species. Evidence shows that Candida spp. have the necessary genetic tools to be able colonize the lungs, and could be a possible causal agent of coinfections in COVID-19 patients. The detection of dispersion of opportunistic pathogens can be unnoticed by classical epidemiology. Epidemiological surveillance against opportunistic fungal pathogens in COVID-19 patients is an immediate need, since the findings presented demonstrate the potential virulence of Candida spp.

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.

Xuanfei Baidu decoction in the treatment of coronavirus disease 2019 (COVID-19): Efficacy and potential mechanisms

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread worldwide and become a major global public health concern. Although novel investigational COVID-19 antiviral candidates such as the Pfizer agent PAXLOVID™, molnupiravir, baricitinib, remdesivir, and favipiravir are currently used to treat patients with COVID-19, there is still a critical need for the development of additional treatments, as the recommended therapeutic options are frequently ineffective against SARS-CoV-2. The efficacy and safety of vaccines remain uncertain, particularly with the emergence of several variants. All 10 versions of the National Health Commission's diagnosis and treatment guidelines for COVID-19 recommend using traditional Chinese medicine. Xuanfei Baidu Decoction (XFBD) is one of the "three Chinese medicines and three Chinese prescriptions" recommended for COVID-19. This review summarizes the clinical evidence and potential mechanisms of action of XFBD for COVID-19 treatment. With XFBD, patients with COVID-19 experience improved clinical symptoms, shorter hospital stay, prevention of the progression of their symptoms from mild to moderate and severe symptoms, and reduced mortality in critically ill patients. The mechanisms of action may be associated with its direct antiviral, anti-inflammatory, immunomodulatory, antioxidative, and antimicrobial properties. High-quality clinical and experimental studies are needed to further explore the clinical efficacy and underlying mechanisms of XFBD in COVID-19 treatment.

The Role of Bacterial and Fungal Superinfection in Critical COVID-19

BACKGROUND

The range of reported rates of bacterial and fungal superinfections in patients with a severe course of COVID-19 is wide, suggesting a lack of standardised reporting.

METHODS

The rates of bacterial and fungal superinfection were assessed using predefined criteria to differentiate between infection and contamination.

RESULTS

Overall, 117 patients admitted to the Intensive Care Unit due to severe COVID-19 were included. Overall, 55% of patients developed a superinfection and 13.6% developed a fungal superinfection (5.9% candidemia and 7.7% CAPA). The rate of ventilator-associated pneumonia was 65.2%. If superinfection was detected, the length of hospital stay was significantly longer and the mortality was especially increased if candidemia was detected. An increased risk of superinfection was observed in patients with pre-existing diabetes mellitus or chronic heart failure. The presence of immunomodulating therapy did not seem to have an impact on the frequency of superinfections.

CONCLUSION

Increased awareness of high superinfection rates, fungal infections in particular, in patients suffering from severe COVID-19 is necessary.

Predictors and Outcomes of Healthcare-Associated Infections among Patients with COVID-19 Admitted to Intensive Care Units in Punjab, Pakistan; Findings and Implications

Healthcare-associated infections (HAIs) have a considerable impact on morbidity, mortality and costs. The COVID-19 pandemic resulted in an appreciable number of hospitalized patients being admitted to intensive care units (ICUs) globally with a greater risk of HAIs. Consequently, there is a need to evaluate predictors and outcomes of HAIs among COVID-19 patients admitted to ICUs. A retrospective study of patients with COVID-19 admitted to ICUs of three tertiary care hospitals in the Punjab province over a five-month period in 2021 was undertaken to ascertain predictors and outcomes of HAIs. Of the 4534 hospitalized COVID-19 patients, 678 were admitted to ICUs, of which 636 patients fulfilled the inclusion criteria. Overall, 67 HAIs were identified among the admitted patients. Ventilator-associated lower respiratory tract infections and catheter-related urinary tract infections were the most frequent HAIs. A significantly higher number of patients who developed HAIs were on anticoagulants (p = 0.003), antithrombotic agents (p < 0.001), antivirals (p < 0.001) and IL-6 inhibiting agents (p < 0.001). Secondary infections were significantly higher in patients who were on invasive mechanical ventilation (p < 0.001), had central venous access (p = 0.023), and urinary catheters (p < 0.001). The mortality rate was significantly higher in those with secondary infections (25.8% vs. 1.2%, p < 0.001). Our study concluded that COVID-19 patients admitted to ICUs have a high prevalence of HAIs associated with greater mortality. Key factors need to be addressed to reduce HAIs.

Massive sequencing of the V3-V4 hypervariable region of bronchoalveolar lavage from patients with COVID-19 and VAP reveals the collapse of the pulmonary microbiota

Background. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is a predisposing factor for the development of healthcare-associated infections, of which ventilator-associated pneumonia (VAP) is one.Hypothesis. VAP is caused by ESKAPE bacteria and other pathogens not detected by microbiological culture.Aim. To elucidate the bacterial pathogens of severe coronavirus disease 2019 (COVID-19) and VAP patients by massive sequencing and to predict their degree of relationship with the age and sex of the patients.Methods. Analysis of ribosomal libraries of the V3-V4 hypervariable region obtained by Illumina sequencing of bronchoalveolar lavages from COVID-19 and VAP (first wave) patients from Hospital Juárez de México.Results. Acinetobacter and Pseudomonas were the main bacterial genera in the bronchoalveolar lavages (BALs) analysed. Other members of the ESKAPE group, such as Enterococcus and Klebsiella, were also identified. Taxonomic composition per patient showed that non-ESKAPE genera were present with significant relative abundances, such as Prevotella, Stenotrophomas, Enterococcus, Mycoplasma, Serratia and Corynebacterium. Kruskal-Wallis analysis proved that VAP acquisition is an adverse event that is not influenced by the sex and age of COVID-19 patients.Discussion. Metagenomic findings in COVID-19/VAP patients highlight the importance of implementing comprehensive microbiological diagnostics by including alternative tools for the detection of the causal agents of healthcare-associated infections (HAIs).Conclusions. Timely identification of bacteria 'not sought' in diagnostic bacteriology laboratories will allow specific and targeted treatments. Implications for the restricted diagnosis of VAP causative agents in COVID-19 patients and the presence of pathogens not detected by classical microbiology are analysed and discussed.

The effect of immunosuppressive therapy on the development of ventilator-associated pneumonia in patients with COVID-19

Aim: It remains unclear whether immunosuppressive treatments such as corticosteroids and IL-6 receptor blockers have an effect on the development of ventilator-associated pneumonia (VAP). The aim of this study was to investigate the effect of immunosuppressive therapy on the development of VAP in critically ill patients with COVID-19. Material and Method: Two hundred thirty five patients with critically ill patients with COVID-19, who were treated in the intensive care unit (ICU) and received mechanical ventilator support, were evaluated retrospectively. VAP development, secondary infections, microorganisms isolated, and resistance patterns were compared between the groups that received and did not receive immunosuppressive therapy, and also the groups that did not receive immunosuppressive therapy, received only corticosteroid, received only tocilizumab, and received corticosteroid plus tocilizumab were compared in the subgroup analysis. Results: In the immunosuppressive treatment group, VAP development (40.2% vs. 21.2%; p=0.001), secondary infection development (48.4% vs. 29.2%; p=0.003), at least one drug resistant bacteria growth (46.7% vs. 27.4%; p=0.001), extensively-drug resistant (XDR) microorganism growth (89.8% vs. 72.7%; p=0.033) were higher than the group that did not receive immunosuppressive treatment. VAP (53.3%; p=0.004), secondary infection (73.3%; p=0.0002), the growth of bacteria resistant to at least one drug (70%; p=0.0003) were highest in the corticosteroid plus tocilizumab group in the subgroup analysis. In addition, XDR (95.5% vs. 72.7%; p=0.032) and pan-drug resistant (PDR) microorganism growth (31.8% vs. 9.1% p=0.032) were higher in the corticosteroid plus tocilizumab group than the no immunosuppressive therapy group. There was no difference between the groups in terms of mortality (p>0.05). Conclusion: Immunosuppressive therapy has been found to potentially enhance the risk of VAP and secondary infections in critically ill patients with COVID-19 pneumonia as well as the growth of bacteria resistant to at least one drug, the length of stay in hospital and ICUs. In addition, it has been evaluated that there may be an increase in the growth of XDR and PDR microorganisms when corticosteroid and tocilizumab are used together. Although there was no difference in mortality, using immunosuppressive therapy may require careful use of targeted antibiotics and longer-term antimicrobial therapy.