Late-onset ventilator-associated pneumonia in nontrauma intensive care unit 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.

Incidence and Predictors of Ventilator-Associated Pneumonia Among Adult Intubated Patients in Bahir Dar Specialized Hospitals, 2021: A Retrospective Follow-Up Study

INTRODUCTION

Ventilator-associated pneumonia refers to pneumonia that happens at least 48 hours after endotracheal intubation. It is associated with high economic costs, longer attributable lengths of stay in the hospital, and high mortality. Therefore, this study aims to determine the incidence and predictors of ventilator-associated pneumonia among adult intensive care unit admitted patients at Bahir Dar Specialized Hospitals.

METHODS

A retrospective follow-up study was conducted among 312 adult intensive care unit admitted patients. A data extraction checklist was used to collect the data. The collected data were coded, cleaned, and entered into EpiData version 3.1 and exported to SPSS version 22 and STATA version 14 for analysis. Descriptive analysis was done by using tables, text and percentages. Bivariable and multivariable log binomial analyses were conducted to identify predictors of ventilator-associated pneumonia. Variables having p-value <0.05 were considered statistically significant.

RESULTS

The study found that 27.9% (95% CI: 23%-33%) of patients developed ventilator-associated pneumonia and the incidence rate of VAP was 45.7 per 1000 ventilator days. Patient's stay more than or equal to 14 days (ARR: 13, 95% CI: 9.3-31) and 7-13 days on MV (ARR: 7.2, 95% CI: 6.2-11), blood transfusion (ARR: 2.8, 95% CI: 1.1-6.9), low GCS (ARR: 2.5, 95% CI: 1.3-5.1), use of corticosteroid (ARR: 2.1, 95% CI: 1.1-4.1), and supine head position (ARR: 8.1, 95% CI: 1.7-40) were identified as independent predictors of ventilator associated pneumonia.

CONCLUSION

Nearly one-fourth of the participants developed ventilator-associated pneumonia. Duration of ventilation, blood transfusion, corticosteroid use, supine head position, and low Glasgow coma scale were significant predictors of ventilator-associated pneumonia.

World-Wide Variation in Incidence of Staphylococcus aureus Associated Ventilator-Associated Pneumonia: A Meta-Regression

Staphylococcus aureus (S. aureus) is a common Ventilator-Associated Pneumonia (VAP) isolate. The objective here is to define the extent and possible reasons for geographic variation in the incidences of S. aureus-associated VAP, MRSA-VAP and overall VAP. A meta-regression model of S. aureus-associated VAP incidence per 1000 Mechanical Ventilation Days (MVD) was undertaken using random effects methods among publications obtained from a search of the English language literature. This model incorporated group level factors such as admission to a trauma ICU, year of publication and use of bronchoscopic sampling towards VAP diagnosis. The search identified 133 publications from seven worldwide regions published over three decades. The summary S. aureus-associated VAP incidence was 4.5 (3.9–5.3) per 1000 MVD. The highest S. aureus-associated VAP incidence is amongst reports from the Mediterranean (mean; 95% confidence interval; 6.1; 4.1–8.5) versus that from Asian ICUs (2.1; 1.5–3.0). The incidence of S. aureus-associated VAP varies by up to three-fold (for the lowest versus highest incidence) among seven geographic regions worldwide, whereas the incidence of VAP varies by less than two-fold. Admission to a trauma unit is the most important group level correlate for S. aureus-associated VAP.

Unusually High Incidences of Staphylococcus aureus Infection within Studies of Ventilator Associated Pneumonia Prevention Using Topical Antibiotics: Benchmarking the Evidence Base

Selective digestive decontamination (SDD, topical antibiotic regimens applied to the respiratory tract) appears effective for preventing ventilator associated pneumonia (VAP) in intensive care unit (ICU) patients. However, potential contextual effects of SDD on Staphylococcus aureus infections in the ICU remain unclear. The S. aureus ventilator associated pneumonia (S. aureus VAP), VAP overall and S. aureus bacteremia incidences within component (control and intervention) groups within 27 SDD studies were benchmarked against 115 observational groups. Component groups from 66 studies of various interventions other than SDD provided additional points of reference. In 27 SDD study control groups, the mean S. aureus VAP incidence is 9.6% (95% CI; 6.9–13.2) versus a benchmark derived from 115 observational groups being 4.8% (95% CI; 4.2–5.6). In nine SDD study control groups the mean S. aureus bacteremia incidence is 3.8% (95% CI; 2.1–5.7) versus a benchmark derived from 10 observational groups being 2.1% (95% CI; 1.1–4.1). The incidences of S. aureus VAP and S. aureus bacteremia within the control groups of SDD studies are each higher than literature derived benchmarks. Paradoxically, within the SDD intervention groups, the incidences of both S. aureus VAP and VAP overall are more similar to the benchmarks.

Cell-type-specific crosstalk between p38 MAPK and Rho signaling in lung micro- and macrovascular barrier dysfunction induced by Staphylococcus aureus-derived pathogens

Lung inflammation and alterations in endothelial cell (EC) micro- and macrovascular permeability are key events to development of acute lung injury. Using ECs derived from human pulmonary artery and lung microvasculature, we investigated the interplay between p38 stress mitogen-activated protein kinase (MAPK) and Rho guanosine triphosphatase signaling in inflammatory and hyperpermeability responses. Both cell types were treated with Staphylococcus aureus-derived peptidoglycan (PepG) and lipoteichoic acid (LTA) with or without pretreatment with p38 MAPK or Rho kinase inhibitors. LTA and PepG increased permeability markedly in both pulmonary macrovascular and microvascular ECs. Agonist-induced hyperpermeability was accompanied by cytoskeletal remodeling, disruption of cell-cell contacts, formation of paracellular gaps, and activation of p38 MAPK, nuclear factor kappa-B (NFκB), and Rho/Rho kinase signaling. In macrovascular ECs, pharmacologic inhibition of Rho kinase with Y27632 suppressed p38 MAP kinase cascade activation significantly, whereas inhibition of p38 MAPK with SB203580 had no effect on Rho activation. In contrast, inhibition of p38 MAPK in microvascular ECs suppressed LTA/PepG-induced activation of Rho, whereas the Rho inhibitor suppressed activation of p38 MAPK. Inhibition of either p38 MAPK or Rho kinase attenuated activation of NFκB signaling substantially. These results demonstrate cell-type-specific differences in signaling induced by Staphylococcus aureus-derived pathogens in pulmonary endothelium. Thus, although Gram-positive bacterial compounds caused barrier dysfunction in both EC types, it was induced by a different pattern of crosstalk between Rho, p38 MAPK, and NFκB signaling. These observations may have important implications in defining microvasculature-specific therapeutic strategies aimed at the treatment of sepsis and acute lung injury induced by Gram-positive bacterial pathogens.

[Healthcare associated infections and severity of illness index of patients in intensive care units]

This study was aimed at verifying the relationship between the severity illness index and the occurrence of healthcare associated infections. A prospective cohort was conducted in an intensive care unit of a university hospital, between August 2009 and February 2001. The Average Severity Index Score was used to evaluate the severity of illness. Data was collected by active surveillance and processed in SPSS. Univariate analysis was carried out, statistical signficance when p < 0.05 and confidence interval of 95%. The severity illness index was related to the occurrence of healthcare associated infection, as well as the length of stay in the intensive care unit, patient type, use of invasive procedure, antimicrobials, colonization and patient outcome (p < 0.05). The occurrence of infections was also apredictive factor for the occurrence of death (p = 0.000). These findings reinforce the idea that the occurrence of healthcare associate infections is a complex multifactorial chain, with emphasis on the clinical severity of the patient.

Comparison of ventilator-associated pneumonia (VAP) rates between different ICUs: Implications of a zero VAP rate

OBJECTIVE

Ventilator-associated pneumonia (VAP) is associated with significant morbidity and mortality. Measures to reduce the incidence of VAP have resulted in institutions reporting a zero or near-zero VAP rates. The implications of zero VAP rates are unclear. This study was done to compare outcomes between two intensive care units (ICU) with one of them reporting a zero VAP rate.

DESIGN, SETTING AND PATIENTS

This study retrospectively compared VAP rates between two ICUs: Utah Valley Regional Medical Center (UVRMC) with 25 ICU beds and American Fork Hospital (AFH) with 9 ICU beds. Both facilities are under the same management and attended by a single group of intensivists. Both ICUs have similar nursing and respiratory staffing patterns. Both ICUs use the same intensive care program for reduction of VAP rates. ICU outcomes between AFH (reporting zero VAP rate) and UVRMC (VAP rate of 2.41/1000 ventilator days) were compared for the years 2007-2008.

MEASUREMENTS AND MAIN RESULTS

UVRMC VAP rates during 2007 and 2008 were 2.31/1000 ventilator days and 2.5/1000 ventilator days respectively compared to a zero VAP rate at AFH. The total days of ventilation, mean days of ventilation per patient and mean duration of ICU stay per patient was higher in the UVRMC group as compared to AFH ICU group. There was no significant difference in mean age and APACHE II score between ICU patients at UVRMC and AFH. There was no statistical difference in rates of VAP and mortality between UVRMC and AFH.

CONCLUSIONS

During comparisons of VAP rate between institutions, a zero VAP rate needs to be considered in the context of overall ventilator days, mean durations of ventilator stay and ICU mortality.

Atrial natriuretic peptide protects against Staphylococcus aureus-induced lung injury and endothelial barrier dysfunction

Lung inflammation and alterations in endothelial cell (EC) permeability are key events to development of acute lung injury (ALI). Protective effects of atrial natriuretic peptide (ANP) have been shown against inflammatory signaling and endothelial barrier dysfunction induced by gram-negative bacterial wall liposaccharide. We hypothesized that ANP may possess more general protective effects and attenuate lung inflammation and EC barrier dysfunction by suppressing inflammatory cascades and barrier-disruptive mechanisms shared by gram-negative and gram-positive pathogens. C57BL/6J wild-type or ANP knockout mice (Nppa-/-) were treated with gram-positive bacterial cell wall compounds, Staphylococcus aureus-derived peptidoglycan (PepG) and/or lipoteichoic acid (LTA) (intratracheal, 2.5 mg/kg each), with or without ANP (intravenous, 2 μg/kg). In vitro, human pulmonary EC barrier properties were assessed by morphological analysis of gap formation and measurements of transendothelial electrical resistance. LTA and PepG markedly increased pulmonary EC permeability and activated p38 and ERK1/2 MAP kinases, NF-κB, and Rho/Rho kinase signaling. EC barrier dysfunction was further elevated upon combined LTA and PepG treatment, but abolished by ANP pretreatment. In vivo, LTA and PepG-induced accumulation of protein and cells in the bronchoalveolar lavage fluid, tissue neutrophil infiltration, and increased Evans blue extravasation in the lungs was significantly attenuated by intravenous injection of ANP. Accumulation of bronchoalveolar lavage markers of LTA/PepG-induced lung inflammation and barrier dysfunction was further augmented in ANP-/- mice and attenuated by exogenous ANP injection. These results strongly suggest a protective role of ANP in the in vitro and in vivo models of ALI associated with gram-positive infection. Thus ANP may have important implications in therapeutic strategies aimed at the treatment of sepsis and ALI-induced gram-positive bacterial pathogens.

The success of enteral nutrition and ICU-acquired infections: a multicenter observational study

BACKGROUND AND AIMS

The objective of this study was to evaluate the relationship between increasing success with enteral nutrition (EN) and acquired infection in the Intensive Care Unit (ICU).

METHODS

We conducted a prospective, multicenter, observational study in 3 Medical/Surgical ICUs. We included patients mechanically ventilated in ICU more than 72 h and who received enteral nutrition only. Charts were reviewed to determine success with EN delivery and clinical outcomes. Suspected infections were adjudicated by 2 or more clinicians to determine the presence or absence of infection (rated as either probable or possible infection).

RESULTS

Of the 207 patients included in this analysis, the average age was 62.0 years; APACHE II score was 23.3; BMI: 28.5; and 73% were medical. Overall, patients received 48.9% (range 0-120%) of their energy and 45.1% (range 0-120%) of their protein requirements from EN. Overall, 25.1% developed an infection after 72 h from admission, 21.7% developed an infection after 96 h from admission, and the 28-day mortality was 29.0%. In a regression model, greater amounts of energy and protein were consistently associated with a reduction in infection. However, estimates only achieved levels near statistical significance for risk of at least 1 probable infection after >96 h (Odds Ratio [0R]: 0.32, 95% Confidence Interval [CI]: 0.10-1.02, p=0.054 and OR: 0.40, 95% CI: 0.18-0.89, p=0.024 per 1000 kcal/day energy and 30 grams/day protein, respectively). In all cases, the OR was lower when considering infections that developed after 96 h compared to infections that developed after 72 h and when considering 'Probable' infections compared to all infections which included 'Possible' infections.

CONCLUSIONS

Successful EN may be associated with a reduction in infectious complications, particularly after 96 h of ICU admission.