De-escalation therapy rates are significantly higher by bronchoalveolar lavage than by tracheal aspirate

Antibiotic strategies in severe nosocomial sepsis: why do we not de-escalate more often?

OBJECTIVES

To assess the use of antibiotic de-escalation in patients with hospital-acquired severe sepsis in an academic setting.

DESIGN

We reviewed all episodes of severe sepsis treated over a 1-yr period in the department of intensive care. Antimicrobial therapy was considered as appropriate when the antimicrobial had in vitro activity against the causative microorganisms. According to the therapeutic strategy in the 5 days after the start of antimicrobial therapy, we classified patients into four groups: de-escalation (interruption of an antimicrobial agent or change of antibiotic to one with a narrower spectrum); no change in antibiotherapy; escalation (addition of a new antimicrobial agent or change in antibiotic to one with a broader spectrum); and mixed changes.

SETTING

A 35-bed medico-surgical intensive care department in which antibiotic strategies are reviewed by infectious disease specialists three times per week.

PATIENTS

One hundred sixty-nine patients with 216 episodes of severe sepsis attributable to a hospital-acquired infection who required broad-spectrum β-lactam antibiotics alone or in association with other anti-infectious agents.

MEASUREMENTS AND MAIN RESULTS

The major sources of infection were the lungs (44%) and abdomen (38%). Microbiological data were available in 167 of the 216 episodes (77%). Initial antimicrobial therapy was inappropriate in 27 episodes (16% of culture-positive episodes). De-escalation was applied in 93 episodes (43%), escalation was applied in 22 episodes (10%), mixed changes were applied in 24 (11%) episodes, and there was no change in empirical antibiotic therapy in 77 (36%) episodes. In these 77 episodes, the reasons given for maintaining the initial antimicrobial therapy included the sensitivity pattern of the causative organisms and previous antibiotic therapy. The number of episodes when the chance to de-escalate may have been missed was small (4 episodes [5%]).

CONCLUSION

Even in a highly focused environment with close collaboration among intensivists and infectious disease specialists, de-escalation may actually be possible in <50% of cases.

Management of antimicrobial use in the intensive care unit

Critically ill patients admitted to the intensive care unit (ICU) are frequently treated with antimicrobials. The appropriate and judicious use of antimicrobial treatment in the ICU setting is a constant clinical challenge for healthcare staff due to the appearance and spread of new multiresistant pathogens and the need to update knowledge of factors involved in the selection of multiresistance and in the patient's clinical response. In order to optimize the efficacy of empirical antibacterial treatments and to reduce the selection of multiresistant pathogens, different strategies have been advocated, including de-escalation therapy and pre-emptive therapy as well as measurement of pharmacokinetic and pharmacodynamic (pK/pD) parameters for proper dosing adjustment. Although the theoretical arguments of all these strategies are very attractive, evidence of their effectiveness is scarce. The identification of the concentration-dependent and time-dependent activity pattern of antimicrobials allow the classification of drugs into three groups, each group with its own pK/pD characteristics, which are the basis for the identification of new forms of administration of antimicrobials to optimize their efficacy (single dose, loading dose, continuous infusion) and to decrease toxicity. The appearance of new multiresistant pathogens, such as imipenem-resistant Pseudomonas aeruginosa and/or Acinetobacter baumannii, carbapenem-resistant Gram-negative bacteria harbouring carbapenemases, and vancomycin-resistant Enterococcus spp., has determined the use of new antibacterials, the reintroduction of other drugs that have been removed in the past due to toxicity or the use of combinations with in vitro synergy. Finally, pharmacoeconomic aspects should be considered for the choice of appropriate antimicrobials in the care of critically ill patients.

De-escalation therapy: is it valuable for the management of ventilator-associated pneumonia?

In therapy for ventilator-associated pneumonia, it is essential to get initial empiric therapy correct; this is challenging because many patients are infected with multidrug-resistant pathogens. The need for achieving appropriate therapy can lead to broad-spectrum empiric therapy, which can represent antibiotic overuse and promote even more resistance. In an effort to combat this problem, de-escalation therapy has been proposed, with the goals of reducing the number of drugs, the spectrum of therapy, and the duration of therapy. This review examines the factors associated with an effective de-escalation strategy and ways to increase the rates of de-escalation in the future.

Antimicrobial de-escalation strategies in hospitalized patients with pneumonia, intra-abdominal infections, and bacteremia

Increasing numbers of serious hospital/healthcare- or community-acquired infections are caused by resistant (often multi-drug resistant) bacterial pathogens. Because delayed or ineffective initial therapy can have severe negative consequences, patients at risk for these types of infections typically receive initial empiric antibiotic therapy with a broad-spectrum regimen covering the most likely pathogens, based on local surveillance data and risk factors for infection with a resistant microorganism. While improving the likelihood of a successful outcome, use of broad-spectrum, often high-dose, empiric antimicrobial therapy also creates pressure for the selection or development of resistant microorganisms, as well as increasing costs and possibly exposing patients to adverse events or collateral damage such as Clostridium difficile-associated disease. De-escalation is a strategy that attempts to balance the competing aims of providing initial empiric therapy that is appropriate and covers the likely pathogens, and limiting antimicrobial exposure and increased risk for emergence of resistant pathogens. More specifically, the de-escalation strategy involves collection of cultures for later microbiological assessment before initiating broad-spectrum empiric therapy covering the most likely pathogens, with the intention of streamlining or de-escalating to a more narrow-spectrum antimicrobial regimen 2-3 days later if warranted by clinical status and culture results. In some cases, negative culture results and subsequent clinical review may allow for termination of initial empiric therapy. In this manner, de-escalation enables more effective targeting of the causative pathogen(s), elimination of redundant therapy, a decrease in antimicrobial pressure for emergence of resistance, and cost savings. This article examines application of the de-escalation strategy to 3 case patients, one with healthcare-associated pneumonia, another with complicated intra-abdominal infection, and a third with central line-associated bacteremia.

De-escalation of antimicrobials in the treatment of bacteraemia due to antibiotic-sensitive pathogens in immunocompetent patients

BACKGROUND

The aim of this study was to examine the safety and efficacy of de-escalating antimicrobial therapy in immunocompetent patients presenting with bacteraemia due to antibiotic-sensitive pathogens.

METHODS

We screened 1,350 positive blood cultures identified in a single, 1,065-bed university hospital over 5 years, and retained 310 cases of bacteraemia due to antibiotic-sensitive pathogens, including (1) methicillin-sensitive staphylococci, (2) penicillin-sensitive streptococci, (3) β-lactam-sensitive (a) Escherichia coli, and (b) Klebsiella species. The efficacy of appropriate initial empirical antimicrobial therapy, the performance of de-escalated pathogen-directed therapy, and the safety and efficacy of de-escalated therapy were evaluated.

RESULTS

Among 270 appropriately treated patients, 16 (6%) died, versus 6 (15%) among 40 who were inappropriately treated (p = 0.04). While 201 of 270 patients (74%) who received appropriate initial empirical therapy were candidates for de-escalation, the treatment was de-escalated in only 79 (39%). De-escalation was associated with (1) a trend toward a lower (a) death rate (1 vs. 5%) and (b) treatment failure (4 vs. 10%), and (2) (a) a 4-day longer median duration and (b) a $50 higher median cost of antimicrobial therapy (p < 0.001).

CONCLUSIONS

When the pathogen was sensitive to antimicrobial therapy and the initial empirical treatment was effective, de-escalation of antimicrobial therapy in immunocompetent patients with bacteraemia was safe and associated with acceptable outcomes. The rate of de-escalation of antimicrobial therapy was low.

De-escalation as part of a global strategy of empiric antibiotherapy management. A retrospective study in a medico-surgical intensive care unit

Introduction

Most data on de-escalation of empirical antimicrobial therapy has focused on ventilator-associated pneumonia. In this retrospective monocentric study, we evaluated de-escalation as part of a global strategy of empiric antibiotherapy management irrespective of the location and the severity of the infection. The goal of this trial was to assess the application of a de-escalation strategy and the impact in terms of re-escalation, recurrent infection and to identify variables associated with de-escalation.

Methods

All consecutive patients treated with empiric antibiotic therapy and hospitalized in the intensive care unit for at least 72 hours within a period of 16 months were included. We compared the characteristics and outcome of patients who have experienced de-escalation therapy with those who have not.

Results

A total of 116 patients were studied corresponding to 133 infections. Antibiotic therapy was de-escalated in 60 cases (45%). De-escalation, primarily accomplished by a reduction in the number of antibiotics used, was observed in 52% of severe sepsis or septic shock patients. Adequate empiric antibiotic and use of aminoglycoside were independently linked with de-escalation. De-escalation therapy was associated with a significant reduction of recurrent infection (19% vs 5% P = 0.01). Mortality was not changed by de-escalation.

Conclusions

As part of a global management of empiric antibiotherapy in an intensive care unit, de-escalation might be safe and feasible in a large proportion of patients.

The Impact of Qualitative Respiratory Cultures on Mortality in Critically III Patients with Hospital-Acquired Pneumonia

This retrospective cohort study evaluated differences in all-cause mortality associated with quantitative versus qualitative cultures in critically ill patients with suspected hospital-acquired pneumonia (HAP). Patients were included if lower respiratory tract (LRT) cultures were obtained and were stratified by culture strategy: invasive (bronchial alveolar lavage [BAL] or nonbronchoscopic BAL) or noninvasive (endotracheal tube aspirate or sputum culture). Mortality data and secondary endpoints were compared between groups. A total of 113 patients met inclusion criteria (invasive = 72, noninvasive = 41). No significant difference in all-cause mortality was detected between the groups (37.5% and 31.7%, respectively; P = 0.54). Secondary endpoints were similar; however, patients in the invasive group had greater mean total antibiotic days of therapy compared to the noninvasive group (21.2 ± 13.5 days vs 15.5 ± 8.3 days, P = 0.01). The present study suggests that using invasive methods to obtain LRT cultures in critically ill patients with suspected HAP did not offer a detectable benefit in mortality or clinical outcomes when compared to noninvasive diagnostic methods.

[Bacterial infections in critically ill patients: review of studies published between 2006 and 2008]

A systematic revision of medical publications between 2006 and 2008 regarding bacterial infections that affect the critical patients was performed. Four subjects were selected: Community-acquired pneumonia, ventilator-associated pneumonia, catheter-related bloodstream infection and new antimicrobial treatments. When dealing with community-acquired pneumonia and due to the absence of completely reliable standards, it is necessary to follow the locally adapted guidelines of clinical practice, to identify patients related to the health-care system and admit patients to the ICU in accordance with the criteria. Regarding the etiological diagnosis of ventilator-associated pneumonia, any microbiological information available must be used. Due to the risk of multidrug bacteria, combined empiric therapy should be initiated immediately and then mono-therapy adjusted to the antibiogram should be established. Already established measures for mechanical ventilation associated pneumonia and catheter-related bacteriemias, which have been effective, should be implemented. The empirical treatment of catheter-related bacteremia must be directed towards the most probable pathogens according to the puncture site. The most recently sold antibiotics are basically directed towards multidrug gram positive resistant bacteria. However, for the treatment of gram negative resistant bacilli, the use of the new antimicrobials must be combined with a new evaluation of the antibiotics that have been used for years and the possibility of choosing different administration forms.

Diagnosis of ventilator-associated pneumonia

INTRODUCTION

Ventilator-associated pneumonia (VAP) is difficult to diagnose. Recent data suggest quantitative endotracheal aspirate (ETA) may be noninferior diagnostically to quantitative bronchoalveolar lavage (BAL). We hypothesized this would be the case.

METHODS

Blind quantitative ETA and BAL were performed on 150 consecutive ventilated patients with suspected VAP in a prospective single-centre medical intensive care unit study over a 2-year inclusion period. Patients were either antibiotic-naive or antibiotic-free for 72 hours. Diagnostic yield, Gram stain and culture results, and impact on antibiotic therapy were assessed. The independent impact of a positive BAL or ETA result on ventilator settings and 28-day mortality was calculated. The BAL/ETA safety was assessed hemodynamically.

RESULTS

Bronchoalveolar lavage had significantly higher diagnostic yield (49.3% vs 34.0%, P = .01), more frequent impact on antibiotic therapy (usually de-escalation) (48.0% vs 32.7%, P = .01), and greater sensitivity (64.1% vs 42.6%, P = .0003) than ETA. There was moderate intertest agreement and no difference in specificity and positive and negative predictive values. A positive BAL or ETA result did not independently alter the frequency of ventilator changes or 28-day mortality. Both procedures were well tolerated.

CONCLUSION

Quantitative BAL is safe and has greater diagnostic utility than ETA for VAP facilitates de-escalation. This study provides support for quantitative BAL in VAP diagnosis.

Hospital-acquired pneumonia: pathophysiology, diagnosis, and treatment

Hospital-acquired pneumonia (HAP) is one of the most common causes of nosocomial infection, morbidity, and mortality in hospitalized patients. Many patient- and disease-specific factors contribute to the pathophysiology of HAP, particularly in the surgical population. Risk-factor modification and inpatient prevention strategies can have a significant impact on the incidence of HAP. While the best diagnostic strategy remains a subject of some debate, prompt and appropriate antimicrobial therapy in patients suspected of having HAP has been shown to significantly decrease mortality. Because the pathogens responsible for HAP are frequently more virulent and have greater resistance to commonly used antimicrobials than other pathogens, clinicians must have knowledge of the resistance patterns at their institutions to choose appropriate therapy.

Does de-escalation of antibiotic therapy for ventilator-associated pneumonia affect the likelihood of recurrent pneumonia or mortality in critically ill surgical patients?

BACKGROUND

Ventilator-associated pneumonia (VAP) is a leading cause of mortality in critically ill patients. Although previous studies have shown that de-escalation therapy (DT) of antibiotics may decrease costs and the development of resistant pathogens, minimal data have shown its effect in surgical patients or in any patients with septic shock. We hypothesized that DT for VAP was not associated with an increased rate of recurrent pneumonia (RP) or mortality in a high acuity cohort of critically ill surgical patients.

METHODS

All surgical intensive care unit (SICU) patients from January 2005 to May 2007 with VAP diagnosed by quantitative bronchoalveolar lavage with a positive threshold of 10,000 CFU/mL were identified. Data collected included age, gender, Acute Physiologic and Chronic Health Evaluation Score III (A3), type of bacterial or other pathogen, antibiotics used for initial and final therapy, mortality, RP, and appropriateness of initial therapy (AIT). Patients were designated as receiving AIT, DT, or escalation of antibiotic therapy based on microbiology for their VAP.

RESULTS

One hundred thirty-eight of 1,596 SICU patients developed VAP during the study period (8.7%). For VAP patients, the mean Acute Physiologic and Chronic Health Evaluation III score was 82.7 points with a mean age of 63.8 years. The RP rate was 30% and did not differ between patients receiving DT (27.3%) and those who did not receive DT (35.1%). Overall mortality was 37% (55% predicted by A3 norms) and did not differ between those receiving DT (33.8%) or not (42.1%). The most common pathogens for primary VAP were methicillin-resistant Staphylococcus aureus (14%), Escherichia coli (11%), and Pseudomonas aeruginosa (9%) whereas P. aeruginosa was the most common pathogen in RP. The AIT for all VAP was 93%. De-escalation of therapy occurred in 55% of patients with AIT whereas 8% of VAP patients required escalation of antibiotic therapy. The most commonly used initial antibiotic choice was vancomycin/piperacillin-tazobactam (16%) and the final choice was piperacillin-tazobactam (20%). Logistic regression demonstrated no specific parameter correlated with development of RP. Higher A3 (Odds ratio, 1.03; 95% confidence interval, 1.01-1.05) was associated with mortality whereas lack of RP (odds ratio, 0.31; 95% confidence interval, 0.12-0.80), and AIT reduced mortality (odds ratio, 0.024; 95% confidence interval, 0.007-0.221). Age, gender, individual pathogen, individual antibiotic regimen, and the use of DT had no effect on mortality.

CONCLUSION

De-escalation therapy did not lead to RP or increased mortality in critically ill surgical patients with VAP. De-escalation therapy was also shown to be safe in patients with septic shock. Because of its acknowledged benefits and lack of demonstrable risks, de-escalation therapy should be used whenever possible in critically ill patients with VAP.

Subthreshold quantitative bronchoalveolar lavage: clinical and therapeutic implications

BACKGROUND

Quantitative bronchoalveolar lavage (qBAL) is used for accurate diagnosis of ventilator-associated pneumonia (VAP). The current study aims at defining the incidence, outcomes and therapeutic implications of false-negative (FN) qBAL.

METHODS

Ventilated trauma, surgery, and burn, patients suspected of VAP underwent bronchoscopic qBAL. VAP was defined as qBAL with >10(5) CFU/mL (threshold). To identify FN BALs, blood cultures drawn concomitant with BAL (+/-5 days of BAL) were analyzed. qBAL specimens growing <10(5) CFU/mL (subthreshold) with blood culture identifying the same organism, without any other source, were classified as FN.

RESULTS

Over 39 months, 246 patients underwent 365 qBALs. Ninety-one specimens had no growth and 274 specimens grew 433 organisms--100 at threshold and 333 at subthreshold strength. Sixteen percent of threshold and 11% of subthreshold organisms were associated with bacteremia. Rates of bacteremia were similar across strengths of growth. Bacteremia at all strengths of growth was more common with Staphylococcal species (methicillin sensitive and resistant) and for hospital-acquired gram-negatives. Rates of bacteremia at all strengths of growth were significantly higher after the first week of hospitalization. Bacteremia worsened outcomes in both threshold group (higher mortality, p < 0.05) and subthreshold group (longer lengths of stay, p < 0.05).

CONCLUSIONS

qBAL has 11% FN rate as measured by blood stream invasion. Propensity of blood stream invasion is related to species of organism (Staphylococcal species and hospital-acquired gram-negatives) and duration of hospitalization, but not to strength of growth. Isolation of these organisms in BAL, at any strength, after the first week should prompt strong consideration for antimicrobial therapy.

Diagnosis of ventilator-associated pneumonia: is there a gold standard and a simple approach?

PURPOSE OF REVIEW

Diagnosis of ventilator-associated pneumonia remains controversial. Different approaches are advocated, but none has yet demonstrated superiority. Diagnosis based on clinical data and aetiological diagnosis of ventilator-associated pneumonia episodes are two concepts that should be combined in an integrative evaluation for ventilator-associated pneumonia. Recent findings in diagnosis are reviewed here.

RECENT FINDINGS

Studies of various diagnostic strategies have been conducted to evaluate whether they influence outcome. Strategies include use of biomarkers (e.g. C-reactive protein and procalcitonin) and use of clinical scores to render the diagnostic process more objective. The appropriateness of the available aetiological diagnostic techniques and their reliability in the absence of a 'gold standard' for diagnosis were also recently addressed. It remains controversial whether type of culture (quantitative or nonquantitative) or sampling method (invasive or noninvasive) influences aetiological diagnosis or outcomes in ventilator-associated pneumonia. It is unlikely that any single approach is the optimal diagnostic assessment whenever ventilator-associated pneumonia is suspected.

SUMMARY

Microbiological data should always be used in association with clinical data when assessing patients with suspected ventilator-associated pneumonia. Integration of these data might be the most simple and effective strategy for diagnosing ventilator-associated pneumonia.