Efficacy of adequate early antibiotic therapy in ventilator-associated pneumonia: influence of disease severity

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Intelligent Neonatal Sepsis Early Diagnosis System for Very Low Birth Weight Infants

Neonatal sepsis is a critical pathology that particularly affects the neonates in intensive care, especially if they are preterm and low birth weight, with an incidence varying between 1and 40% according to the onset (early or late) of the disease. Prompt diagnostic and therapeutic interventions could reduce the high percentage of mortality that characterises this pathology, especially in the premature and low weight neonates. The HeRO score analyses the heart rate variability and represents the risk of contracting sepsis because of the hospitalization in the neonatal intensive care unit up to 24 h before the clinical signs. However, it has been demonstrated that the HeRO score can produce many false-positive cases, thus leading to the start of unnecessary antibiotic therapy. In this work, the authors propose an optimised artificial neural network model able to diagnose sepsis early based on the HeRO score along with a series of parameters strictly connected to the risk of neonatal sepsis. The proposed methodology shows promising results, outperforming the diagnostic accuracy of the only HeRO score and reducing the number of false positives, thus revealing itself to be a promising tool for supporting the clinicians in the daily clinical practice.

The Role of Age, Neutrophil Infiltration and Antibiotics Timing in the Severity of Streptococcus pneumoniae Pneumonia. Insights from a Multi-Level Mathematical Model Approach

Bacterial pneumonia is one of the most prevalent infectious diseases and has high mortality in sensitive patients (children, elderly and immunocompromised). Although an infection, the disease alters the alveolar epithelium homeostasis and hinders normal breathing, often with fatal consequences. A special case is hospitalized aged patients, which present a high risk of infection and death because of the community acquired version of the Streptococcus pneumoniae pneumonia. There is evidence that early antibiotics treatment decreases the inflammatory response during pneumonia. Here, we investigate mechanistically this strategy using a multi-level mathematical model, which describes the 24 first hours after infection of a single alveolus from the key signaling networks behind activation of the epithelium to the dynamics of the local immune response. With the model, we simulated pneumonia in aged and young patients subjected to different antibiotics timing. The results show that providing antibiotics to elderly patients 8 h in advance compared to young patients restores in aged individuals the effective response seen in young ones. This result suggests the use of early, probably prophylactic, antibiotics treatment in aged hospitalized people with high risk of pneumonia.

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

OBJECTIVES

To investigate the respective impact of ventilator-associated pneumonia and ICU-hospital-acquired pneumonia on the 30-day mortality of ICU patients.

DESIGN

Longitudinal prospective studies.

SETTING

French ICUs.

PATIENTS

Patients at risk of ventilator-associated pneumonia and ICU-hospital-acquired pneumonia.

INTERVENTIONS

The first three episodes of ventilator-associated pneumonia or ICU-hospital-acquired pneumonia were handled as time-dependent covariates in Cox models. We adjusted using the case-mix, illness severity, Simplified Acute Physiology Score II score at admission, and procedures and therapeutics used during the first 48 hours before the risk period. Baseline characteristics of patients with regard to the adequacy of antibiotic treatment were analyzed, as well as the Sequential Organ Failure Assessment score variation in the 2 days before the occurrence of ventilator-associated pneumonia or ICU-hospital-acquired pneumonia. Mortality was also analyzed for Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species(ESKAPE) and P. aeruginosa pathogens.

MEASUREMENTS AND MAIN RESULTS

Of 14,212 patients who were admitted to the ICUs and who stayed for more than 48 hours, 7,735 were at risk of ventilator-associated pneumonia and 9,747 were at risk of ICU-hospital-acquired pneumonia. Ventilator-associated pneumonia and ICU-hospital-acquired pneumonia occurred in 1,161 at-risk patients (15%) and 176 at-risk patients (2%), respectively. When adjusted on prognostic variables, ventilator-associated pneumonia (hazard ratio, 1.38 (1.24-1.52); p < 0.0001) and even more ICU-hospital-acquired pneumonia (hazard ratio, 1.82 [1.35-2.45]; p < 0.0001) were associated with increased 30-day mortality. The early antibiotic therapy adequacy was not associated with an improved prognosis, particularly for ICU-hospital-acquired pneumonia. The impact was similar for ventilator-associated pneumonia and ICU-hospital-acquired pneumonia mortality due to P. aeruginosa and the ESKAPE group.

CONCLUSIONS

In a large cohort of patients, we found that both ICU-hospital-acquired pneumonia and ventilator-associated pneumonia were associated with an 82% and a 38% increase in the risk of 30-day mortality, respectively. This study emphasized the importance of preventing ICU-hospital-acquired pneumonia in nonventilated patients.

The Impact of Early Adequate Treatment on Extubation and Discharge Alive of Patients With Pseudomonas aeruginosa-Related Ventilator-Associated Pneumonia

OBJECTIVES

We aim to examine the effect of early adequate treatment in comparison with inadequate or delayed treatment on being extubated or discharged alive over time, in patients with Pseudomonas aeruginosa-related ventilator-associated pneumonia.

DESIGN

Retrospective analyses of a prospective observational multicenter cohort study.

SETTING

ICU.

PATIENTS

Patients of the French prospective database (OUTCOMEREA) were included if they acquired a ventilator-associated pneumonia due to P. aeruginosa between 1997 and 2014 and were mechanically ventilated for more than 48 hours.

INTERVENTIONS

Early adequate treatment in comparison with inadequate or delayed adequate treatment.

MEASUREMENTS AND MAIN RESULTS

Multistate models were applied to estimate the time-dependent probability of being extubated or discharged alive, and separate Cox regression analyses were used to assess the treatment effect on all important events that influence the outcome of interest. A propensity score-adjusted innovative regression technique was used for a combined and comprehensive patient-relevant summary effect measure. No evidence was found for a difference between adequate and inadequate or delayed treatment on being extubated or discharged alive. However, for all patients, the probability of being extubated or discharged alive remains low and does not exceed 50% even 40 days after a P. aeruginosa-related ventilator-associated pneumonia.

CONCLUSIONS

Early adequate treatment does not seem to be associated with an improved prognosis. Its potential benefit requires further investigation in larger observational studies.

Establishment of a Predictive Model Related to Pathogen Invasion for Infectious Diseases and Its Diagnostic Value in Fever of Unknown Origin

The present study aimed to establish a list of parameters indicative of pathogen invasion and develop a predictive model to distinguish the etiologies of fever of unknown origin (FUO) into infectious and non-infectious causes. From January 2014 to September 2017, 431 patients with FUO were prospectively enrolled in the study population. This study established a list of 26 variables from the following 4 aspects: host factors, epidemiological factors, behavioral factors, and iatrogenic factors. Predefined predicted variables were included in a multivariate logistic regression analysis to develop a predictive model. The predictive model and the corresponding scoring system were developed using data from the confirmed diagnoses and 9 variables were eventually identified. These factors were incorporated into the predictive model. This model discriminated between infectious and non-infectious causes of FUO with an AUC of 0.72, sensitivity of 0.71, and specificity of 0.63. The predictive model and corresponding scoring system based on factors concerning pathogen invasion appear to be reliable screening tools to discriminate between infectious and non-infectious causes of FUO.

Carbapenems vs. alternative β-lactams for the treatment of nosocomial pneumonia: A systematic review and meta-analysis

BACKGROUND

Carbapenems have shown efficacy in treating nosocomial pneumonias in clinical trials despite a reported low lung penetration compared with other β-lactams. Preserving the clinical activity of carbapenems through stewardship efforts is essential. The aim of this review was to identify any differences in outcomes potentially as a function of decreased penetration.

METHODS

PubMed and the Cochrane Library were systematically searched for clinical trials comparing carbapenems with other anti-pseudomonal β-lactams for treatment of nosocomial pneumonia through to end December 2016. Trials reporting clinical and microbiological outcomes associated with treatment were included. Pediatric studies and those with uneven comparators (e.g., carbapenem vs. combination Gram-negative therapy) were excluded. Fixed effects models were used to evaluate the impact of treatment on the odds of clinical failure, death, or microbiological failure.

RESULTS

252 unique articles were identified; five met inclusion criteria and comprised 640 patients in the carbapenem group and 634 patients in the β-lactam group. No differences in clinical failure (odds ratio [OR] 1.08, 95% confidence interval [CI] [0.81-1.44], I2=16%) or mortality (OR 0.75, CI 0.57-1.11, I2=0%) were noted between groups. Patients infected with P. aeruginosa and treated with imipenem were more likely to experience clinical failure (OR 4.21, CI 1.51-11.12, I2=44%) and to develop resistance to the study carbapenem (OR 2.86, CI 1.08-6.44, I2= 13%) than those treated with alternative β-lactams.

CONCLUSIONS

No differences in clinical outcomes were observed between carbapenems and non-carbapenem β-lactams in nosocomial pneumonias. Those infected with P. aeruginosa fared worse and were more likely to have resistance develop if they were treated with imipenem. Additional studies are warranted.

Effect of a multifaceted educational intervention for anti-infectious measures on sepsis mortality: a cluster randomized trial

PURPOSE

Guidelines recommend administering antibiotics within 1 h of sepsis recognition but this recommendation remains untested by randomized trials. This trial was set up to investigate whether survival is improved by reducing the time before initiation of antimicrobial therapy by means of a multifaceted intervention in compliance with guideline recommendations.

METHODS

The MEDUSA study, a prospective multicenter cluster-randomized trial, was conducted from July 2011 to July 2013 in 40 German hospitals. Hospitals were randomly allocated to receive conventional continuous medical education (CME) measures (control group) or multifaceted interventions including local quality improvement teams, educational outreach, audit, feedback, and reminders. We included 4183 patients with severe sepsis or septic shock in an intention-to-treat analysis comparing the multifaceted intervention (n = 2596) with conventional CME (n = 1587). The primary outcome was 28-day mortality.

RESULTS

The 28-day mortality was 35.1% (883 of 2596 patients) in the intervention group and 26.7% (403 of 1587 patients; p = 0.01) in the control group. The intervention was not a risk factor for mortality, since this difference was present from the beginning of the study and remained unaffected by the intervention. Median time to antimicrobial therapy was 1.5 h (interquartile range 0.1-4.9 h) in the intervention group and 2.0 h (0.4-5.9 h; p = 0.41) in the control group. The risk of death increased by 2% per hour delay of antimicrobial therapy and 1% per hour delay of source control, independent of group assignment.

CONCLUSIONS

Delay in antimicrobial therapy and source control was associated with increased mortality but the multifaceted approach was unable to change time to antimicrobial therapy in this setting and did not affect survival.

Empirical Combination Antibiotic Therapy Improves the Outcome of Nosocomial Meningitis or Ventriculitis in Neuro-Critical Care Unit Patients

BACKGROUND

Nosocomial meningitis and ventriculitis (MEN) are serious complications in neuro-critical care unit (NCCU) patients. Few data are available on the risk factors and mortality rates among NCCU patients with these disorders caused by multi-drug-resistant (MDR) pathogens. Our aim was to identify the risk factors for MEN caused by such pathogens and in-hospital deaths in critically ill neurologic patients and to evaluate the impact of empirical combination antibiotic therapy (ECAT) on the outcomes of these patients.

METHODS

We conducted a retrospective study of critically ill neurologic patients having nosocomial MEN who were admitted to the NCCU in a university teaching hospital from January 2003 to December 2013, with MEN being defined using the modified U.S. Centers for Disease Control and Prevention criteria for nosocomial infections.

RESULTS

In total, 6,149 consecutive NCCU patients were screened; 132 had MEN. Logistic regression analysis demonstrated that MDR MEN was related to infection with gram-negative (GN) bacteria (odds ratio 3.16; 95% confidence interval [CI] 1.08-9.25; p = 0.036), and inadequate initial antibiotic therapy (odds ratio 9.80; 95% CI 3.79-25.32; p < 0.001). The ECAT was associated with a lower mortality rate (hazard ratio 0.35; 95% CI 0.14-0.86; p = 0.022) in Cox proportional hazard regression analysis. The other variable independently associated with a greater mortality rate was a greater Simplified Acute Physiology Score II (hazard ratio 1.07; 95% CI 1.01-1.13; p = 0.018).

CONCLUSIONS

Initial combination therapy improves the in-hospital mortality rate among NCCU patients with nosocomial MEN. Inadequate initial antibiotic therapy and GN infection were associated with MDR MEN.

An Argument for the Use of Aminoglycosides in the Empiric Treatment of Ventilator-Associated Pneumonia

BACKGROUND

Appropriate empiric antibiotic therapy for ventilator-associated pneumonia improves outcomes. Controversy exists regarding the inclusion of aminoglycosides in empiric therapeutic regimens.

METHODS

The Ovid and Cochrane databases were searched for relevant literature regarding the use of aminoglycosides in combination therapy for ventilator-associated pneumonia. The data supporting the use of aminoglycosides in certain populations and strategies to limit toxicity are summarized.

RESULTS

In patients at high risk of infection with antibiotic-resistant gram-negative bacilli and in those with severe illness, aminoglycosides improve clinical outcomes. In critically ill populations, short-duration therapy and high-dose extended-interval dosing of aminoglycosides can improve therapeutic efficacy while limiting nephrotoxicity.

CONCLUSIONS

In selected populations using appropriate dosing strategies, aminoglycosides should be considered for empiric treatment of ventilator-associated pneumonia.

Does it Matter if we get it right? Impact of appropriateness of empiric antimicrobial therapy among surgical patients

Previous studies have shown conflicting evidence regarding the impact of inappropriate, initial antibiotic therapy. The purpose of this study was to evaluate the impact of inappropriate empiric antimicrobial therapy for the treatment of infection among surgical patients. We hypothesized that inappropriate empiric antimicrobial therapy would predict increased mortality risk compared with appropriate therapy. This was a retrospective analysis of a prospectively maintained database of all surgical patients admitted to a tertiary care center from 1996 to 2007 and treated for sepsis. "Appropriate" empiric antibiotic treatment was determined by sensitivity testing. Demographics and comorbidities, infection sites, infection organisms, and outcomes were compared between inappropriately and appropriately treated groups. Multivariable log-binomial regression was performed. There were 2,855 patients (7,158 infectious episodes) identified by culture analysis as either appropriately or inappropriately treated. Three hundred seventeen (15%) inappropriately treated infectious episodes resulted in death compared with 718 (14%) of the appropriately treated infectious episodes. After adjusting for statistically significant variables, inappropriately treated episodes of infection were not found to be associated with an increased risk for mortality compared with appropriately treated episodes of infection (relative risk, 1.0; 95% confidence interval, 0.99 - 1.02; P = 0.36). Our study observed no difference in mortality between appropriately and inappropriately treated infections within a surgical population.

The association between time to antibiotics and relevant clinical outcomes in emergency department patients with various stages of sepsis: a prospective multi-center study

Introduction

In early sepsis stages, optimal treatment could contribute to prevention of progression to severe sepsis. Therefore, we investigated if there was an association between time to antibiotics and relevant clinical outcomes in hospitalized emergency department (ED) patients with mild to severe sepsis stages.

Methods

This is a prospective multicenter study in three Dutch EDs. Patients were stratified into three categories of illness severity, as assessed by the predisposition, infection, response, and organ failure (PIRO) score: PIRO score 1 to 7, 8 to 14 and >14 points, reflected low, intermediate, and high illness severity, respectively. Consecutive hospitalized ED patients with a suspected infection who were treated with intravenous antibiotics were eligible to participate in the study. The primary outcome measure was the number of surviving days outside the hospital at day 28 which was used as an inverse measure of hospital length of stay (LOS). The secondary outcome measure was 28-day mortality, taking into account the time to mortality.

Multivariable Cox regression analysis was used to estimate the association between time to antibiotics and the primary and secondary outcome measures corrected for confounders, including appropriateness of antibiotics and initial ED resuscitation, in three categories of illness severity.

Results

Of the 1,168 included patients, 112 died (10%), while 85% and 95% received antibiotics within three and six hours, respectively. No association between time to antibiotics and surviving days outside the hospital or mortality was found. Only in PIRO group 1 to 7 was delayed administration of antibiotics (>3 hours) associated with an increase in surviving days outside the hospital at day 28 (hazard ratio: 1.46, 95% confidence interval: 1.05 to 2.02 after correction for potential confounders).

Conclusions

In ED patients with mild to severe sepsis who received antibiotics within six hours after ED presentation, a reduction in time to antibiotics was not found to be associated with an improvement in relevant clinical outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0936-3) contains supplementary material, which is available to authorized users.

Adverse in-hospital events are associated with increased in-hospital mortality and length of stay in patients with or at risk of acute respiratory distress syndrome

OBJECTIVE

To explore the effect of various adverse hospital events on short- and long-term outcomes in a cohort of acutely ill hospitalized patients.

PATIENTS AND METHODS

In a secondary analysis of a retrospective cohort of acutely ill hospitalized patients with sepsis, shock, or pneumonia or undergoing high-risk surgery who were at risk for or had developed acute respiratory distress syndrome between 2001 and 2010, the effects of potentially preventable hospital exposures and adverse events (AEs) on in-hospital and intensive care unit (ICU) mortality, length of stay, and long-term survival were analyzed. Adverse effects chosen for inclusion were inadequate empiric antimicrobial coverage, hospital-acquired aspiration, medical or surgical misadventure, inappropriate blood product transfusion, and injurious tidal volume while on mechanical ventilation.

RESULTS

In 828 patients analyzed, the distribution of 0, 1, 2, and 3 or more cumulative AEs was 521 (63%), 126 (15%), 135 (16%), and 46 (6%) patients, respectively. The adjusted odds ratios (95% CI) for in-hospital mortality in patients who had 1, 2, and 3 or more AEs were 0.9 (0.5-1.7), 0.9 (0.5-1.6), and 1.4 (0.6-3.3), respectively. One AE increased the length of stay, difference between means (95% CI), in the hospital by 8.7 (3.8-13.7) days and in the ICU by 2.4 (0.6-4.2) days.

CONCLUSION

Potentially preventable hospital exposure to AEs is associated with prolonged ICU and hospital lengths of stay. Implementation of effective patient safety interventions is of utmost priority in acute care hospitals.

[First-line anti-infective treatment in sepsis]

BACKGROUND

The Surviving Sepsis Campaign strongly recommends that intravenous antibiotic therapy should be started as early as possible, ideally within the first hour of recognition of severe sepsis or septic shock. There is ample evidence that failure to initiate early antimicrobial treatment correlates with increased morbidity and mortality.

OBJECTIVES

The purpose of this work was to review the recent literature regarding optimal initial antimicrobial treatment in patients with severe sepsis and sepsis shock.

MATERIALS AND METHODS

A literature review was performed.

RESULTS

The most frequently quoted papers claiming the overriding prognostic importance of early administered antibiotics are retrospective data analyses. However, an equivalent number of studies report that a group of septic patients do not benefit from early administration of antibiotics, but can also be harmed. In these patients, watchful waiting with administration of a targeted antibiotic can be used, thus, avoiding the possible collateral damage from excessive treatment with antibiotics. Treatment with monotherapy is adequate in most cases.

CONCLUSION

The administration of antibiotics based on the local epidemiology should be initiated quickly in critically ill patients with severe sepsis and septic shock. In patients who are not in septic shock, treatment can be withheld, while awaiting further studies or clinical assessment to confirm the suspicion of infection.

Risk factors for infection with multidrug-resistant bacteria in non-ventilated patients with hospital-acquired pneumonia

OBJECTIVE:

To identify risk factors for the development of hospital-acquired pneumonia (HAP) caused by multidrug-resistant (MDR) bacteria in non-ventilated patients.

METHODS:

This was a retrospective observational cohort study conducted over a three-year period at a tertiary-care teaching hospital. We included only non-ventilated patients diagnosed with HAP and presenting with positive bacterial cultures. Categorical variables were compared with chi-square test. Logistic regression analysis was used to determine risk factors for HAP caused by MDR bacteria.

RESULTS:

Of the 140 patients diagnosed with HAP, 59 (42.1%) were infected with MDR strains. Among the patients infected with methicillin-resistant Staphylococcus aureus and those infected with methicillin-susceptible S. aureus, mortality was 45.9% and 50.0%, respectively (p = 0.763). Among the patients infected with MDR and those infected with non-MDR gram-negative bacilli, mortality was 45.8% and 38.3%, respectively (p = 0.527). Univariate analysis identified the following risk factors for infection with MDR bacteria: COPD; congestive heart failure; chronic renal failure; dialysis; urinary catheterization; extrapulmonary infection; and use of antimicrobial therapy within the last 10 days before the diagnosis of HAP. Multivariate analysis showed that the use of antibiotics within the last 10 days before the diagnosis of HAP was the only independent predictor of infection with MDR bacteria (OR = 3.45; 95% CI: 1.56-7.61; p = 0.002).

CONCLUSIONS:

In this single-center study, the use of broad-spectrum antibiotics within the last 10 days before the diagnosis of HAP was the only independent predictor of infection with MDR bacteria in non-ventilated patients with HAP.

The PIRO (predisposition, insult, response, organ dysfunction) model: toward a staging system for acute illness

Multimodal therapy for diseases like cancer has only become practicable following the development of staging systems like the TNM (tumor, nodes, metastases) system. Staging enables the identification of subgroups of patients with a disease who not only have a differing prognosis, but who are also more likely to benefit from a specific therapeutic modality. Critically ill patients represent a highly heterogeneous population for whom multiple therapeutic options are potentially available, each carrying not only the potential for differential benefit, but also the potential for differential harm. The PIRO system (predisposition, insult, response, organ dysfunction) is a template proposal for a staging system for acute illness that incorporates assessment of pre-morbid baseline susceptibility (predisposition), the specific disorder responsible for acute illness (insult), the response of the host to that insult, and the resulting degree of organ dysfunction. However the creation of a valid, robust, and clinically useful system presents significant challenges arising from the complexity of the disease state, the lack of a clear phenotype, the confounding influence of the effects of therapy and of cultural and socio-economic factors, and the relatively low profile of acute illness with clinicians and the general public. This review summarizes the rationale for such a model of illness stratification and the results of preliminary cohort studies testing the concept. It further proposes two strategies for building a staging system, recognizing that this will be a demanding undertaking that will require decades of work.

Immune response in severe infection: could life-saving drugs be potentially harmful?

Critically ill patients suffer a high rate of nosocomial infection with secondary sepsis being a common cause of death. Usage of antibiotics and catecholamines is often necessary, but it can compromise complex immune response to infection. This review explores influence of these life-saving drugs on host immune response to severe infection.

Empirical Antibiotic Therapy for Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is the most common infectious complication in the intensive care unit. It can increase duration of mechanical ventilation, length of stay, costs, and mortality. Improvements in the administration of empirical antibiotic therapy have potential to reduce the complications of VAP. This review will discuss the current data addressing empirical antibiotic therapy and the effect on mortality in patients with VAP. It will also address factors that could improve the administration of empirical antibiotics and directions for future research.

Lack of clinically evident signs of organ failure affects ED treatment of patients with severe sepsis

BACKGROUND

It is not known whether lack of recognition of organ failure explains the low compliance with the "Surviving Sepsis Campaign" (SSC) guidelines. We evaluated whether compliance was higher in emergency department (ED) sepsis patients with clinically recognizable signs of organ failure compared to patients with only laboratory signs of organ failure.

METHODS

Three hundred twenty-three ED patients with severe sepsis and septic shock were prospectively included. Multivariable binary logistic regression was used to assess if clinical and biochemical signs of organ failure were associated with compliance to a SSC-based resuscitation bundle. In addition, two-way analysis of variance was used to investigate the relation between the predisposition, infection, response and organ failure (PIRO) score (3 groups: 1-7, 8-14, 15-24) as a measure of illness severity and time to antibiotics with disposition to ward or ICU as effect modifier.

RESULTS

One hundred twenty-five of 323 included sepsis patients with new-onset organ failure were admitted to the ICU, and in all these patients the SSC resuscitation bundle was started. Respiratory difficulty, hypotension and altered mental status as clinically recognizable signs of organ failure were independent predictors of 100% compliance and not illness severity per se. Corrected ORs (95% CI) were 3.38 (1.08-10.64), 2.37 (1.07-5.23) and 4.18 (1.92-9.09), respectively. Septic ED patients with clinically evident organ failure were more often admitted to the ICU compared to a ward (125 ICU admissions, P < 0.05), which was associated with shorter time to antibiotics [ward: 127 (113-141) min; ICU 94 (80-108) min (P = 0.005)].

CONCLUSIONS

The presence of clinically evident compared to biochemical signs of organ failure was associated with increased compliance with a SSC-based resuscitation bundle and admission to the ICU, suggesting that recognition of severe sepsis is an important barrier for successful implementation of quality improvement programs for septic patients. In septic ED patients admitted to the ICU, the time to antibiotics was shorter compared to patients admitted to a normal ward.

Inadequate treatment of ventilator-associated and hospital-acquired pneumonia: risk factors and impact on outcomes

BACKGROUND

Initial antimicrobial therapy (AB) is an important determinant of clinical outcome in patients with severe infections as pneumonia, however well-conducted studies regarding prognostic impact of inadequate initial AB in patients who are not undergoing mechanical ventilation (MV) are lacking. In this study we aimed to identify the risk factors for inadequate initial AB and to determine its subsequent impact on outcomes in both ventilator associated pneumonia (VAP) and hospital acquired pneumonia (HAP).

METHODS

We retrospectively studied the accuracy of initial AB in patients with pneumonia in a university hospital in Turkey. A total of 218 patients with HAP and 130 patients with VAP were included. For each patient clinical, radiological and microbiological data were collected. Stepwise multivariate logistic regression analysis was used for risk factor analysis. Survival analysis was performed by using Kaplan-Meier method with Log-rank test.

RESULTS

Sixty six percent of patients in VAP group and 41.3% of patients in HAP group received inadequate initial AB. Multiple logistic regression analysis revealed that the risk factors for inadequate initial AB in HAP patients were; late-onset HAP (OR = 2.35 (95% CI, 1.05-5.22; p = 0.037) and APACHE II score at onset of HAP (OR = 1.06 (95% CI, 1.01-1.12); p = 0.018). In VAP patients; antibiotic usage in the previous three months (OR = 3.16 (95% CI, 1.27-7.81); p = 0.013) and admission to a surgical unit (OR = 2.9 (95% CI, 1.17-7.19); p = 0.022) were found to be independent risk factors for inadequate initial AB. No statistically significant difference in crude hospital mortality and 28-day mortality was observed between the treatment groups in both VAP and HAP. However we showed a significant increase in length of hospital stay, duration of mechanical ventilation and a prolonged clinical resolution in the inadequate AB group in both VAP and HAP.

CONCLUSION

Our data suggests that the risk factors for inadequate initial AB are indirectly associated with the acquisition of resistant bacteria for both VAP and HAP. Although we could not find a positive correlation between adequate initial AB and survival; empirical AB with a broad spectrum should be initiated promptly to improve secondary outcomes.

Aggressive versus conservative initiation of antimicrobial treatment in critically ill surgical patients with suspected intensive-care-unit-acquired infection: a quasi-experimental, before and after observational cohort study

BACKGROUND

Antimicrobial treatment in critically ill patients can either be started as soon as infection is suspected or after objective data confirm an infection. We postulated that delaying antimicrobial treatment of patients with suspected infections in the surgical intensive care unit (SICU) until objective evidence of infection had been obtained would not worsen patient mortality.

METHODS

We did a 2-year, quasi-experimental, before and after observational cohort study of patients aged 18 years or older who were admitted to the SICU of the University of Virginia (Charlottesville, VA, USA). From Sept 1, 2008, to Aug 31, 2009, aggressive treatment was used: patients suspected of having an infection on the basis of clinical grounds had blood cultures sent and antimicrobial treatment started. From Sept 1, 2009, to Aug 31, 2010, a conservative strategy was used, with antimicrobial treatment started only after objective findings confirmed an infection. Our primary outcome was in-hospital mortality. Analyses were by intention to treat.

FINDINGS

Admissions to the SICU for the first and second years were 762 and 721, respectively, with 101 patients with SICU-acquired infections during the aggressive year and 100 patients during the conservative year. Compared with the aggressive approach, the conservative approach was associated with lower all-cause mortality (13/100 [13%] vs 27/101 [27%]; p=0·015), more initially appropriate therapy (158/214 [74%] vs 144/231 [62%]; p=0·0095), and a shorter mean duration of therapy (12·5 days [SD 10·7] vs 17·7 [28·1]; p=0·0080). After adjusting for age, sex, trauma involvement, acute physiology and chronic health evaluation (APACHE) II score, and site of infection, the odds ratio for the risk of mortality in the aggressive therapy group compared with the conservative therapy group was 2·5 (95% CI 1·5-4·0).

INTERPRETATION

Waiting for objective data to diagnose infection before treatment with antimicrobial drugs for suspected SICU-acquired infections does not worsen mortality and might be associated with better outcomes and use of antimicrobial drugs.

FUNDING

National Institutes of Health.

Investigating hospital heterogeneity with a multi-state frailty model: application to nosocomial pneumonia disease in intensive care units

Background

Multistate models have become increasingly useful to study the evolution of a patient’s state over time in intensive care units ICU (e.g. admission, infections, alive discharge or death in ICU). In addition, in critically-ill patients, data come from different ICUs, and because observations are clustered into groups (or units), the observed outcomes cannot be considered as independent. Thus a flexible multi-state model with random effects is needed to obtain valid outcome estimates.

Methods

We show how a simple multi-state frailty model can be used to study semi-competing risks while fully taking into account the clustering (in ICU) of the data and the longitudinal aspects of the data, including left truncation and right censoring. We suggest the use of independent frailty models or joint frailty models for the analysis of transition intensities. Two distinct models which differ in the definition of time t in the transition functions have been studied: semi-Markov models where the transitions depend on the waiting times and nonhomogenous Markov models where the transitions depend on the time since inclusion in the study. The parameters in the proposed multi-state model may conveniently be computed using a semi-parametric or parametric approach with an existing R package FrailtyPack for frailty models. The likelihood cross-validation criterion is proposed to guide the choice of a better fitting model.

Results

We illustrate the use of our approach though the analysis of nosocomial infections (ventilator-associated pneumonia infections: VAP) in ICU, with “alive discharge” and “death” in ICU as other endpoints. We show that the analysis of dependent survival data using a multi-state model without frailty terms may underestimate the variance of regression coefficients specific to each group, leading to incorrect inferences. Some factors are wrongly significantly associated based on the model without frailty terms. This result is confirmed by a short simulation study. We also present individual predictions of VAP underlining the usefulness of dynamic prognostic tools that can take into account the clustering of observations.

Conclusions

The use of multistate frailty models allows the analysis of very complex data. Such models could help improve the estimation of the impact of proposed prognostic features on each transition in a multi-centre study. We suggest a method and software that give accurate estimates and enables inference for any parameter or predictive quantity of interest.

Attributable mortality of ventilator-associated pneumonia

PURPOSE OF REVIEW

To critically discuss the attributable mortality of ventilator-associated pneumonia (VAP) and potential sources of variation.

RECENT FINDINGS

The review will cover the available estimates (0-50%). It will also explore the source of variation because of definition of VAP (being lower if inaccurate), case-mix issues (being lower for trauma patients), the severity of underlying illnesses (being maximal when the severity of underlying illness is intermediate), and on the characteristics and the severity of the VAP episode. Another important source of variation is the use of poorly appropriate statistical models (estimates biased by lead time bias and competing events). New extensions of survival models which take into account the time dependence of VAP occurrence and competing risks allow less biased estimation as compared with traditional models.

SUMMARY

Attributable mortality of VAP is about 6%. Accurate diagnostic methods are key to properly estimating it. Traditional statistical models should no longer be used to estimate it. Prevention efforts targeted on patients with intermediate severity may result in the most important outcome benefits.

Improving severe sepsis outcomes: cost and time to first antibiotic dose

This study was conducted to determine the effect of an empiric antimicrobial guide on clinical and economic outcomes related to severe sepsis. As all critical care nurses know, severe sepsis is often life-threatening. The study found that an empiric antimicrobial guide specific for severe sepsis was associated with a reduced length of stay, a significantly earlier time to first dose antibiotic, and significantly lower total and variable hospital costs.

Early use of imipenem/cilastatin and vancomycin followed by de-escalation versus conventional antimicrobials without de-escalation for patients with hospital-acquired pneumonia in a medical ICU: a randomized clinical trial

Introduction

Although early use of broad-spectrum antimicrobials in critically ill patients may increase antimicrobial adequacy, uncontrolled use of these agents may select for more-resistant organisms. This study investigated the effects of early use of broad-spectrum antimicrobials in critically ill patients with hospital-acquired pneumonia.

Methods

We compared the early use of broad-spectrum antimicrobials plus subsequent de-escalation (DE) with conventional antimicrobial treatment (non-de-escalation, NDE) in critically ill patients with hospital-acquired pneumonia (HAP). This open-label, randomized clinical trial was performed in patients in a tertiary-care center medical intensive care unit (MICU) in Korea. Patients (n = 54) randomized to the DE group received initial imipenem/cilastatin plus vancomycin with subsequent de-escalation according to culture results, whereas patients randomized to the NDE group (n = 55) received noncarbapenem, nonvancomycin empiric antimicrobials.

Results

Between November 2004 and October 2006, 109 MICU patients with HAP were enrolled. Initial antimicrobial adequacy was significantly higher in the DE than in the NDE group for Gram-positive organisms (100% versus 14.3%; P < 0.001), but not for Gram-negative organisms (64.3% versus 85.7%; P = 0.190). Mean intensive care unit (ICU) stay, and 14-day, 28-day, and overall mortality rates did not differ in the two groups. Among culture-positive patients, mortality from methicillin-resistant Staphylococcus aureus (MRSA) pneumonia was higher in the DE group, even after early administration of vancomycin. Multidrug-resistant organisms, especially MRSA, were more likely to emerge in the DE group (adjusted hazard ratio for emergence of MRSA, 3.84; 95% confidence interval, 1.06 to 13.91).

Conclusions

The therapeutic advantage of early administration of broad-spectrum antimicrobials, especially with vancomycin, was not evident in this study.

Pneumonia due to Pseudomonas aeruginosa: part II: antimicrobial resistance, pharmacodynamic concepts, and antibiotic therapy

Pseudomonas aeruginosa carries a notably higher mortality rate than other pneumonia pathogens. Because of its multiple mechanisms of antibiotic resistance, therapy has always been challenging. This problem has been magnified in recent years with the emergence of multidrug-resistant (MDR) pathogens often unharmed by almost all classes of antimicrobials. The objective of this article is to assess optimal antimicrobial therapy based on in vitro activity, animal studies, and pharmacokinetic/pharmacodynamic (PK/PD) observations so that evidence-based recommendations can be developed to maximize favorable clinical outcomes. Mechanisms of antimicrobial resistance of P aeruginosa are reviewed. A selective literature review of laboratory studies, PK/PD concepts, and controlled clinical trials of antibiotic therapy directed at P aeruginosa pneumonia was performed. P aeruginosa possesses multiple mechanisms for inducing antibiotic resistance to antimicrobial agents. Continuous infusion of antipseudomonal β-lactam antibiotics enhances bacterial killing. Although the advantages of combination therapy remain contentious, in vitro and animal model studies plus selected meta-analyses of clinical trials support its use, especially in the era of MDR. Colistin use and the role of antibiotic aerosolization are reviewed. An evidence-based algorithmic approach based on severity of illness, Clinical Pulmonary Infection Score, and combination antibiotic therapy is presented; clinical outcomes may be improved, and the emergence of MDR pathogens should be minimized with this approach.

Clinical practice guidelines for hospital-acquired pneumonia and ventilator-associated pneumonia in adults

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are important causes of morbidity and mortality, with mortality rates approaching 62%. HAP and VAP are the second most common cause of nosocomial infection overall, but are the most common cause documented in the intensive care unit setting. In addition, HAP and VAP produce the highest mortality associated with nosocomial infection. As a result, evidence-based guidelines were prepared detailing the epidemiology, microbial etiology, risk factors and clinical manifestations of HAP and VAP. Furthermore, an approach based on the available data, expert opinion and current practice for the provision of care within the Canadian health care system was used to determine risk stratification schemas to enable appropriate diagnosis, antimicrobial management and nonantimicrobial management of HAP and VAP. Finally, prevention and risk-reduction strategies to reduce the risk of acquiring these infections were collated. Future initiatives to enhance more rapid diagnosis and to effect better treatment for resistant pathogens are necessary to reduce morbidity and improve survival.

Impact of ureido/carboxypenicillin resistance on the prognosis of ventilator-associated pneumonia due to Pseudomonas aeruginosa

Introduction

Although Pseudomonas aeruginosa is a leading pathogen responsible for ventilator-associated pneumonia (VAP), the excess in mortality associated with multi-resistance in patients with P. aeruginosa VAP (PA-VAP), taking into account confounders such as treatment adequacy and prior length of stay in the ICU, has not yet been adequately estimated.

Methods

A total of 223 episodes of PA-VAP recorded into the Outcomerea database were evaluated. Patients with ureido/carboxy-resistant P. aeruginosa (PRPA) were compared with those with ureido/carboxy-sensitive P. aeruginosa (PSPA) after matching on duration of ICU stay at VAP onset and adjustment for confounders.

Results

Factors associated with onset of PRPA-VAP were as follows: admission to the ICU with septic shock, broad-spectrum antimicrobials at admission, prior use of ureido/carboxypenicillin, and colonization with PRPA before infection. Adequate antimicrobial therapy was more often delayed in the PRPA group. The crude ICU mortality rate and the hospital mortality rate were not different between the PRPA and the PSPA groups. In multivariate analysis, after controlling for time in the ICU before VAP diagnosis, neither ICU death (odds ratio (OR) = 0.73; 95% confidence interval (CI): 0.32 to 1.69; P = 0.46) nor hospital death (OR = 0.87; 95% CI: 0.38 to 1.99; P = 0.74) were increased in the presence of PRPA infection. This result remained unchanged in the subgroup of 87 patients who received adequate antimicrobial treatment on the day of VAP diagnosis.

Conclusions

After adjustment, and despite the more frequent delay in the initiation of an adequate antimicrobial therapy in these patients, resistance to ureido/carboxypenicillin was not associated with ICU or hospital death in patients with PA-VAP.

Current challenges in the management of the infected patient

PURPOSE OF REVIEW

Management of hospital-associated infections (HAIs) has been made more challenging by the increasing proportion of immunocompromised or otherwise severely ill patients and increasing prevalence of antibiotic-resistant pathogens in this environment. This review examines strategies to optimize clinical outcomes and lower healthcare costs for patients with HAIs by focusing on patient-related, pathogen-related, and drug-related factors.

RECENT FINDINGS

Factors have converged to increase the risk of infection with antibiotic-resistant pathogens in the current hospital environment, including the increasing prevalence of resistant species and number of hospitalized patients with conditions increasingly susceptible to infection with drug-resistant bacteria. Although the list of bacterial pathogens associated with HAIs has been fairly constant over time, the prevalence and resistance profile of these individual species continues to evolve. Periodic antibiograms should be utilized to access local patterns of resistance within the different hospital wards. Outcomes for patients with HAIs are optimized with early empiric treatment with an appropriate regimen, selected on the basis of patient characteristics and local resistance patterns. Dosing strategies should be utilized to ensure that the efficacy of an appropriate antibiotic is optimized, by achieving the pharmacodynamic target predictive of its efficacy. Using these strategies improves quality of care and is associated with lower overall healthcare costs.

SUMMARY

Bacterial resistance is an increasing problem in the hospital environment, and has been associated with poorer clinical outcomes and elevated healthcare costs. By using patient characteristics, local antibiograms, and dosing strategies to achieve an optimal pharmacodynamic profile, early appropriate empiric therapy can be utilized to improve clinical outcomes, minimize the development of resistance, and reduce healthcare costs.

Empiric, broad-spectrum antibiotic therapy with an aggressive de-escalation strategy does not induce gram-negative pathogen resistance in ventilator-associated pneumonia

BACKGROUND

Early, empiric, broad-spectrum antibiotics followed by de-escalation to pathogen-specific therapy is the standard of care for ventilator-associated pneumonia (VAP). In our surgical intensive care unit (SICU), imipenem-cilastatin (I-C) in combination with tobramycin (TOB) or levofloxacin (LEV) has been used until quantitative bronchoalveolar lavage results are finalized, at which time de-escalation occurs to pathogen-specific agents. With this practice, however, alterations in antimicrobial resistance remain a concern. Our hypothesis was that this strict regimen does not alter antimicrobial susceptibility of common gram-negative VAP pathogens in our SICU.

METHODS

After Institutional Review Board approval, a retrospective review of SICU-specific antibiograms was performed for the sensitivities of common gram-negative VAP pathogens. Time periods were defined as early (January-June 2005) and late (July-December 2006). Chart review of empiric and de-escalation antibiotic usage was obtained. Data were collated, and statistical significance was assessed with the chi-square test using the on-line Simple Interactive Statistical Analysis tool.

RESULTS

Imipenem-cilastatin was used 198 times for empiric VAP coverage (811 patient-days), whereas TOB and LEV were given a total of 149 (564 patient-days) and 61 (320 patient-days) times, respectively. Collectively, the susceptibility of gram-negative organisms to I-C did not change (early 91.4%; late 97%; p = 0.33). Individually, non-significant trends to greater sensitivity to I-C were noted for both Pseudomonas aeruginosa (early 85.7%; late 90.9%; p = 0.73) and Acinetobacter baumannii (early 80%; late 100%; p = 0.13). Further, both TOB (early 77.1%; late 70.0%; p = 0.49) and LEV (early 74.3%; late 70.0%; p = 0.67) were found to maintain their susceptibility profiles. The frequency of resistant gram-positive VAPs was unchanged during the study period. Our de-escalation compliance (by 96 h) was 78% for I-C, 77.2% for TOB, and 59% for LEV. When infections requiring I-C were removed from the analysis, de-escalation compliance was improved to 92%.

CONCLUSIONS

In our SICU, early, empiric broad-spectrum VAP therapy followed by de-escalation to pathogen-specific agents did not alter antimicrobial resistance and is a valid practice. Further, our compliance with de-escalation practices was higher than published rates.

A New Approach to Ventilator-associated Pneumonia Based on the PIRO System

Several new scoring systems have been developed over recent years to assess the degree of organ failure (e.g., Acute Physiology and Chronic Health Evaluation [APACHE] II, APACHE III, Sequential Organ Failure Assessment [SOFA], Simplified Acute Physiology Score [SAPS] II, and Multiple Organ Dysfunction Score [MODS]). Most of these were models generated based on the concepts of sepsis, severe sepsis and septic shock. In 2001, an International Sepsis Definition Conference updated these terms in order to facilitate standardized enrolment into clinical trials, but due to their simplicity and easy use physicians rapidly adopted them for daily clinical practice [1].

Systematic review and meta-analysis of the efficacy of appropriate empiric antibiotic therapy for sepsis

Quantifying the benefit of early antibiotic treatment is crucial for decision making and can be assessed only in observational studies. We performed a systematic review of prospective studies reporting the effect of appropriate empirical antibiotic treatment on all-cause mortality among adult inpatients with sepsis. Two reviewers independently extracted data. Risk of bias was assessed using the Newcastle-Ottawa score. We calculated unadjusted odds ratios (ORs) with 95% confidence intervals for each study and extracted adjusted ORs, with variance, methods, and covariates being used for adjustment. ORs were pooled using random-effects meta-analysis. We examined the effects of methodological and clinical confounders on results through subgroup analysis or mixed-effect meta-regression. Seventy studies were included, of which 48 provided an adjusted OR for inappropriate empirical antibiotic treatment. Inappropriate empirical antibiotic treatment was associated with significantly higher mortality in the unadjusted and adjusted comparisons, with considerable heterogeneity occurring in both analyses (I(2) > 70%). Study design, time of mortality assessment, the reporting methods of the multivariable models, and the covariates used for adjustment were significantly associated with effect size. Septic shock was the only clinical variable significantly affecting results (it was associated with higher ORs). Studies adjusting for background conditions and sepsis severity reported a pooled adjusted OR of 1.60 (95% confidence interval = 1.37 to 1.86; 26 studies; number needed to treat to prevent one fatal outcome, 10 patients [95% confidence interval = 8 to 15]; I(2) = 46.3%) given 34% mortality with inappropriate empirical treatment. Appropriate empirical antibiotic treatment is associated with a significant reduction in all-cause mortality. However, the methods used in the observational studies significantly affect the effect size reported. Methods of observational studies assessing the effects of antibiotic treatment should be improved and standardized.

Cost and mortality prediction using polymerase chain reaction pathogen detection in sepsis: evidence from three observational trials

Introduction

Delays in adequate antimicrobial treatment contribute to high cost and mortality in sepsis. Polymerase chain reaction (PCR) assays are used alongside conventional cultures to accelerate the identification of microorganisms. We analyze the impact on medical outcomes and healthcare costs if improved adequacy of antimicrobial therapy is achieved by providing immediate coverage after positive PCR reports.

Methods

A mathematical prediction model describes the impact of PCR-based rapid adjustment of antimicrobial treatment. The model is applied to predict cost and medical outcomes for 221 sepsis episodes of 189 post-surgical and intensive care unit (ICU) sepsis patients with available PCR data from a prospective, observational trial of a multiplex PCR assay in five hospitals. While this trial demonstrated reduction of inadequate treatment days, data on outcomes associated with reduced inadequate initial antimicrobial treatment had to be obtained from two other, bigger, studies which involved 1,147 (thereof 316 inadequately treated) medical or surgical ICU patients. Our results are reported with the (5% to 95%) percentile ranges from Monte Carlo simulation in which the input parameters were randomly and independently varied according to their statistical characterization in the three underlying studies. The model allows predictions also for different patient groups or PCR assays.

Results

A total of 13.1% of PCR tests enabled earlier adequate treatment. We predict that cost for PCR testing (300 €/test) can be fully recovered for patients above 717 € (605 € to 1,710 €) daily treatment cost. A 2.6% (2.0 to 3.2%) absolute reduction of mortality is expected. Cost per incremental survivor calculates to 11,477 € (9,321 € to 14,977 €) and incremental cost-effectiveness ratio to 3,107 € (2,523 € to 4,055 €) per quality-adjusted life-year. Generally, for ICU patients with >25% incidence of inadequate empiric antimicrobial treatment, and at least 15% with a positive blood culture, PCR represents a cost-neutral adjunct method.

Conclusions

Rapid PCR identification of microorganisms has the potential to become a cost-effective component for managing sepsis. The prediction model tested with data from three observational trials should be utilized as a framework to deepen insights when integrating more complementary data associated with utilization of molecular assays in the management of sepsis.

Influence of an Institution-Specific Sepsis Protocol on the Adequacy of Empiric Antimicrobial Therapy

Objective

A sepsis protocol including institution-specific antibiotic recommendations based on local susceptibility patterns was implemented at our institution. The purpose of this investigation was to determine the impact of these recommendations on the adequacy of initial empiric therapy in patients with severe sepsis admitted to the intensive care unit.

Methods

This was a single-center, retrospective, observational study conducted in a medical intensive care unit at a university-affiliated medical center. Charts of patients identified as having sepsis in our sepsis database from November 2004 to September 2006 were retrospectively reviewed. Adequacy of initial therapy was assessed, as were the number of antibiotics used per patient and 28-day mortality.

Results

One hundred nine patients met inclusion criteria for the evaluation. Thirty-eight patients were in the pre-protocol group and 71 patients were in the post-protocol group. Adequacy of initial therapy increased from 68% pre protocol to 85% post protocol ( P < 0.05). A secondary analysis showed that if antibiotic recommendations had been followed exactly according to protocol, the number of antibiotics per patient would decrease from 2.47 to 2.11 ( P = 0.017) without changing adequacy of initial treatment.

Conclusion

Implementation of a sepsis protocol containing institution-specific antibiotic recommendations was associated with an increased percent of patients receiving adequate empiric antibiotic therapy. Strictly adhering to the institution-specific antibiotic recommendations could result in fewer antibiotics used per patient without reducing the adequacy of empiric treatment.

Incidence of multidrug-resistant organisms causing ventilator-associated pneumonia in a tertiary care hospital: a nine months' prospective study

BACKGROUND:

Ventilator-associated pneumonia (VAP) is an important intensive care unit (ICU) infection in mechanically ventilated patients. VAP occurs approximately in 9-27% of all intubated patients. Due to the increasing incidence of multidrug-resistant organisms in ICUs, early and correct diagnosis of VAP is an urgent challenge for an optimal antibiotic treatment.

AIM OF THE STUDY:

The aim of the study was to assess the incidence of VAP caused by multidrug-resistant organisms in the multidisciplinary intensive care unit (MICU) of our tertiary care 1,400-bedded hospital.

MATERIALS AND METHODS:

This prospective study was done in the period from December 2005 to August 2006, enrolling patients undergoing mechanical ventilation (MV) for >48 h. Endotracheal aspirates (ETA) were collected from patients with suspected VAP, and quantitative cultures were performed on all samples. VAP was diagnosed by the growth of pathogenic organism ≥10⁵ cfu/ml.

RESULTS:

Incidence of VAP was found to be 45.4% among the mechanically ventilated patients, out of which 47.7% had early-onset (<5 days MV) VAP and 52.3% had late-onset (>5 days MV) VAP. Multiresistant bacteria, mainly Acinetobacter spp. (47.9%) and Pseudomonas aeruginosa (27%), were the most commonly isolated pathogens in both types of VAP. Most of the isolates of Escherichia coli (80%) and Klebsiella pneumoniae (100%) produced extended-spectrum beta lactamases (ESBLs). As many as 30.43% isolates of Acinetobacter spp. showed production of AmpC beta lactamases among all types of isolates. Metallo-beta lactamases (MBLs) were produced by 50% of Pseudomonas aeruginosa and 21.74% of Acinetobacter spp.

CONCLUSION:

High incidence (45.4%) of VAP and the potential multidrug-resistant organisms are the real threat in our MICU. This study highlighted high incidence of VAP in our setup, emphasizing injudicious use of antimicrobial therapy. Combined approaches of rotational antibiotic therapy and education programs might be beneficial to fight against these MDR pathogens and will also help to decrease the incidence of VAP.

Attributable mortality of ventilator-associated pneumonia: respective impact of main characteristics at ICU admission and VAP onset using conditional logistic regression and multi-state models

PURPOSE

Methods for estimating the excess mortality attributable to ventilator-associated pneumonia (VAP) should handle VAP as a time-dependent covariate, since the probability of experiencing VAP increases with the time on mechanical ventilation. VAP-attributable mortality (VAP-AM) varies with definitions, case-mix, causative microorganisms, and treatment adequacy. Our objectives here were to compare VAP-AM estimates obtained using a traditional cohort analysis, a multistate progressive disability model, and a matched-cohort analysis; and to compare VAP-AM estimates according to VAP characteristics.

METHODS

We used data from 2,873 mechanically ventilated patients in the Outcomerea database. Among these patients from 12 intensive care units, 434 (15.1%) experienced VAP; of the remaining patients, 1,969 (68.5%) were discharged alive and 470 (16.4%) died. With the multistate model, VAP-AM was 8.1% (95% confidence interval [95%CI], 3.1-13.1%) for 120 days' complete observation, compared to 10.4% (5.6-24.5%) using a matched-cohort approach (2,769 patients) with matching on mechanical ventilation duration followed by conditional logistic regression. VAP-AM was higher in surgical patients and patients with intermediate (but not high) Simplified Acute Physiologic Score II values at ICU admission. VAP-AM was significantly influenced by time to VAP but not by resistance of causative microorganisms. Higher Logistic Organ Dysfunction score at VAP onset dramatically increased VAP-AM (to 31.9% in patients with scores above 7).

CONCLUSION

A multistate model that appropriately handled VAP as a time-dependent event produced lower VAP-AM values than conditional logistic regression. VAP-AM varied widely with case-mix. Disease severity at VAP onset markedly influenced VAP-AM; this may contribute to the variability of previous estimates.

Pneumonia

Hospital-acquired pneumonia (HAP) is usually caused by bacterial, viral, or fungal pathogens that occur ≥48 h after hospital admission.^1,2 Overall, more than 80% of HAP episodes are related to invasive airway management (in patients with endotracheal intubation or tracheostomy) with mechanical ventilation, which is known as ventilator-associated pneumonia (VAP).³ VAP is defined as pneumonia developing more than 48 h after intubation and mechanical ventilation. Healthcare-associated pneumonia (HCAP) is part of the continuum of pneumonia, which includes patients who were hospitalized in an acute-care hospital for ≥2 days within 90 days of the infection; resided in a long-term care facility; received recent intravenous antibiotic therapy, chemotherapy, or wound care within the past 30 days of the current infection; or attended a hospital or hemodialysis clinic.^1,2 Although this document focuses more on HAP and VAP, many of the principles are also relevant to the management of HCAP. HAP, VAP, and HCAP are the second most common nosocomial infections after urinary tract infection, but are the leading causes of mortality due to hospital-acquired infections.^4,5

The utility of the clinical pulmonary infection score

The most common infectious complication in critically ill patients is ventilator-associated pneumonia. Ventilator-associated pneumonia has significant morbidity and mortality, prolongs mechanical ventilation, and extends length of hospitalization. Despite its prevalence and impact, uniform diagnostic standards are lacking. The Centers for Disease Control, American Thoracic Society, and Infectious Diseases Society of America have recommended focus on improving preventive measures, establishing widely available and accurate diagnostic tools, and improving ventilator-associated pneumonia management with length of therapy guidelines. The purpose of this article is to review the evidence supporting the clinical pulmonary infection score as an adjunct to distinguish and detect clinically relevant ventilator-associated pneumonia and its use to guide length of therapy. This score combines clinical diagnostic criteria (tracheal secretion quantification and body temperature) with routinely obtained laboratory data (white blood cell count and oxygenation parameters), radiographic data, and bacteriological culture results. Limitations of clinical pulmonary infection score will be discussed.

Impact of inappropriate antibiotic therapy on mortality in patients with ventilator-associated pneumonia and blood stream infection: a meta-analysis

OBJECTIVES

Studies have found that initial treatment of ventilator-associated pneumonia (VAP) and blood stream infections (BSI) with inappropriate antimicrobial therapy is associated with higher rates of mortality, but additional studies have failed to confirm this.

METHODS

Databases were searched to identify studies that met the following criteria: observational trials, patients with VAP or BSI receiving appropriate and inappropriate antimicrobial therapy, and mortality data. We conducted random-effects model meta-analyses, both with and without adjustment.

RESULTS

Meta-analyses of VAP studies using unadjusted and adjusted data indicated that inappropriate therapy significantly increased patients' odds of mortality (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.51-3.63; P = .0001, I 2 = 28.5% and OR, 3.03; 95% CI, 1.12-8.19; P = .0292, I 2 = 89.2%, respectively). Meta-analyses of BSI studies using unadjusted and adjusted data showed that inappropriate therapy significantly increased patients' odds of mortality (OR, 2.33; 95% CI, 1.96-2.76; P < .0001, I 2 = 48.7% and OR, 2.28; 95% CI, 1.43-3.65; P = .0006, I 2 = 88.2%, respectively).

CONCLUSIONS

There appears to be an association between initial inappropriate antimicrobial therapy and increased mortality in patients with VAP and BSI.

Delay of active antimicrobial therapy and mortality among patients with bacteremia: impact of severe neutropenia

Increasing bacterial antimicrobial resistance has prompted physicians to choose broad-spectrum antimicrobials in order to reduce the likelihood of inactive empirical therapy. However, for bacteremic patients already receiving supportive care, it is unclear whether delay of active antimicrobial therapy significantly impacts patient outcomes. We performed a retrospective cohort study of patients with monomicrobial bloodstream infections at a large urban hospital in the United States from 2001 to 2006. We assessed the impact of delay of active antimicrobial therapy on mortality by using multivariable logistic regression modeling with and without propensity score methodology. We evaluated 1,523 episodes of monomicrobial bacterial bloodstream infections at our institution. Nine hundred eighty-three bacteremic episodes (64.5%) were treated with an active antimicrobial agent within 24 h of the index blood culture; the remaining 540 episodes (35.5%) were considered to have delay of active antimicrobial therapy. In adjusted analysis, among patients in the non-intensive-care-unit setting with an absolute neutrophil count (ANC) of <100 cells/microl, delay was associated with increased mortality (odds ratio [OR], 18.0; 95% confidence interval [CI], 2.84 to 114.5; P < 0.01); among intensive-care-unit patients with an ANC of <100 cells/microl, the effect of delay on mortality was nearly significant (OR, 5.56; 95% CI, 0.85 to 36.3; P = 0.07). However, for patients who were nonneutropenic (ANC, >500 cells/microl) or had ANCs of 100 to 500 cells/microl, delay was not associated with increased mortality. While the delay of active antimicrobial therapy was not significantly associated with higher mortality for most patients in this cohort, patients with severe neutropenia appeared to be vulnerable.

The role of carbapenems in initial therapy for serious Gram-negative infections

The treatment of patients with serious Gram-negative infections must be both prompt and correct. Numerous studies have demonstrated that mortality risk is significantly increased when the initial antibiotic regimen does not adequately cover the infecting pathogen. Furthermore, changing to an appropriate regimen once culture results are available does not reduce this risk. Therefore, one must empirically treat serious infections with a regimen that covers likely pathogens. Selecting such a regimen is complicated by the increasing prevalence of resistance to commonly used antibiotics. Moreover, multidrug-resistant pathogens, once limited to hospital-acquired infections, are increasingly being detected in community-acquired infections, especially those involving the urinary and gastrointestinal tracts or in immunocompromised patients. Consequently, the initial antibiotic regimen must have a broad spectrum of activity that includes potential resistant pathogens, as indicated by the local antibiogram. Many multidrug-resistant pathogens remain susceptible to carbapenems despite increasing worldwide antibiotic resistance. This article reviews the role played by carbapenems in the initial treatment of serious Gram-negative infections and the potential effect of emerging resistance on this role.