Ventilator-Associated Pneumonia Patients who Do Not Reduce Bacteria from the Lungs have a Worse Prognosis

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.

Repeat blood culture positive for B. pseudomallei indicates an increased risk of death from melioidosis

Melioidosis, a bacterial infection caused by Burkholderia pseudomallei, is notoriously difficult to cure despite appropriate antimicrobial therapy and has a mortality rate of up to 40%. We demonstrate that a blood culture positive for B. pseudomallei taken at the end of the first and/or second week after hospitalization for melioidosis is a strong prognostic factor for death (adjusted odds ratio = 4.2, 95% confidence interval = 2.1-8.7, P < 0.001 and adjusted odds ratio = 2.6, 95% confidence interval = 1.1-6.0, P = 0.03, respectively). However, repeat cultures of respiratory secretions, urine, throat swabs, or pus/surface swabs provide no prognostic information. This finding highlights the need for follow-up blood cultures in patients with melioidosis.

A European survey of antibiotic management of methicillin-resistant Staphylococcus aureus infection: current clinical opinion and practice

Although the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) varies across Europe, healthcare-associated MRSA infections are common in many countries. Despite several national guidelines, the approach to treatment of MRSA infections varies across the continent, and there are multiple areas of management uncertainty for which there is little clinical evidence to guide practice. A faculty, convened to explore some of these areas, devised a survey that was used to compare the perspectives of infection specialists from across Europe on the management of MRSA infections with those of the faculty specialists. The survey instrument, a web-based questionnaire, was sent to 3840 registered delegates of the 19th European Congress of Clinical Microbiology and Infectious Diseases, held in April 2009. Of the 501 (13%) respondents to the survey, 84% were infection/microbiology specialists and 80% were from Europe. This article reports the survey results from European respondents, and shows a broad range of opinion and practice on a variety of issues pertaining to the management of minor and serious MRSA infections, such as pneumonia, bacteraemia, and skin and soft tissue infections. The issues include changing epidemiology, when and when not to treat, choice of treatment, and duration and route of treatment. The survey identified areas where practice can be improved and where further research is needed, and also identified areas of pan-European consensus of opinion that could be applied to European guidelines for the management of MRSA infection.

The use of carbapenems in the treatment of serious infections

Inadequate initial antimicrobial treatment in serious infections leads to increased mortality. Achieving adequate treatment is increasingly difficult because of the increasing prevalence of multidrug-resistant (MDR) pathogens. The carbapenems are potent, broad-spectrum antibiotics that have been shown to be safe and efficacious therapies in the treatment of serious infections. This review is intended to compare the 4 major members of the carbapenem class, which include imipenem, meropenem, ertapenem, and doripenem, with other widely used antimicrobial agents in the intensive care unit (ICU). The carbapenems are potent, broad-spectrum antibiotics that have been shown to be safe and efficacious therapies in the treatment of serious infections. They provide better gram-negative coverage than other beta-lactams and are stable against extended-spectrum beta-lactamases and AmpC beta-lactamases, making them effective in the treatment of many MDR bacteria. The newly approved carbapenem, doripenem, may help preserve the utility of the carbapenem class.

Surveillance culture utility and safety using low-volume blind bronchoalveolar lavage in the diagnosis of ventilator-associated pneumonia

BACKGROUND AND OBJECTIVES

Surveillance cultures may improve the prediction of ventilator-associated pneumonia (VAP) and empirical antibiotic selection. This study examined the utility and patient safety of blind, non-protected, low-volume mini-bronchial lavage (BM-BAL) surveillance cultures in predicting VAP.

METHODOLOGY

A prospective, cohort study was performed in a large general intensive care unit. BM-BALs were collected within 12 h of admission then thrice weekly. Each BM-BAL was screened by Gram staining for intracellular organisms and then quantitatively cultured. VAP was diagnosed using the Clinical Pulmonary Infection Score. The concordance for isolates from the BM-BAL was assessed against concurrently collected endotracheal aspirates (EA).

RESULTS

Four hundred and twelve patients requiring a minimum of 48 h of mechanical ventilation were enrolled. Fifty patients developed 58 episodes of VAP. Concordant pathogens were found in 85% of BM-BAL specimens collected 2 days prior to VAP onset. Their antibiograms were stable over the preceding 4 days. The isolation of pathogens with colony counts >or=10(4) cfu/mL from BM-BAL performed 2 days prior to the clinical onset of VAP had a sensitivity of 84%, specificity of 50%, positive predictive value of 31% and a negative predictive value of 93% for predicting the development of VAP. BM-BAL WCC, quantification of bacterial growth and the percentage of intracellular organisms were not helpful in predicting VAP diagnosis.

CONCLUSIONS

BM-BAL surveillance cultures are well tolerated and useful in predicting the pathogens and their antibiograms causing VAP. Diagnostic specimen collection at the time of VAP onset is still required as surveillance cultures may be negative even one day prior to VAP onset.

Repeat bronchoalveolar lavage to guide antibiotic duration for ventilator-associated pneumonia

BACKGROUND

Using an arbitrary day cutoff or clinical signs to decide the duration of antibiotic therapy for ventilator-associated pneumonia (VAP) may be suboptimal for some patients. We sought to determine whether antibiotic duration for VAP can be safely abbreviated in trauma patients using repeat bronchoalveolar lavage (BAL).

METHODS

This was an observational case-controlled pilot study. Fifty-two patients were treated for VAP using a repeat BAL clinical pathway. Definitive antibiotic therapy for VAP was discontinued if pathogen growth was <10,000 colony forming units/mL on repeat BAL performed on day 4 of antibiotic therapy (responder), otherwise therapy was continued per managing team. A matched control group of 52 VAP patients treated before (immediately consecutive) the pathway was used for comparison.

RESULTS

Antibiotic duration in pathway patients was shorter than control patients (9.8 days +/- 3.8 days vs. 16.7 days +/- 7.4 days; p < 0.001), including nonfermenting gram-negative bacilli VAP (10.7 days +/- 4.1 days vs. 14.4 days +/- 4.2 days; p < 0.001). There were no differences in pneumonia relapse, mechanical ventilator-free intensive care unit (ICU) days, ICU-free hospital days, or mortality. Of study group isolates, 86 (82.7%) responded on repeat BAL and were treated for 8.8 days +/- 3.3 days. Of these without concomitant infections (n = 65), antibiotic duration was 7.3 days +/- 1.2 days compared with 14.4 days +/- 2.6 days for nonresponding isolates (n = 18) (p < 0.001).

CONCLUSIONS

Repeat BAL decreased the duration of antibiotic therapy for VAP in trauma patients. More adequately powered investigations are needed to appropriately determine the effects of this strategy on patient outcome.

De-escalation therapy in ventilator-associated pneumonia

PURPOSE OF REVIEW

To describe the use of a 'de-escalation' strategy to deliver appropriate empiric therapy for ventilator-associated pneumonia, without the overuse of antibiotics.

RECENT FINDINGS

Initial empiric therapy can be appropriate in 80-90% of ventilator-associated pneumonia patients, if it is selected on the basis of local microbiologic data or individual patient surveillance cultures. Following initial empiric therapy, de-escalation means using microbiologic and clinical data to change from an initial broad-spectrum, multidrug empiric therapy regimen to a therapy with fewer antibiotics and agents of narrower spectrum. In spite of early success with this approach there is an opportunity to de-escalate more often, particularly in patients with negative pretherapy cultures, and in those whose cultures show multidrug-resistant organisms, including Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus. In addition, it is possible to reduce the total duration of therapy, particularly when the initial therapy is accurate. When de-escalation has been employed, it has led to less antibiotic usage, shorter durations of therapy, fewer episodes of secondary pneumonia and reduced mortality, without increasing the frequency of antibiotic resistance.

SUMMARY

De-escalation is a promising strategy for optimizing the responsible use of antibiotics while allowing the delivery of prompt and appropriate empiric therapy of ventilator-associated pneumonia.

[Assessment of patients with poor resolution of HAP]

Emphasis in VAP management is now shifting to the effectiveness of antibiotic therapy and its effect on subsequent mortality. As many as 62% of patients with VAP meet a set of objective criteria for failure to respond. The predominant microorganisms associated with failure of therapy are Pseudomonas aeruginosa and methicillin-resistant S. aureus (MRSA). Multiple causes of failure to respond in VAP exist: compromised host immunity, occult antibiotic resistance, inadequate antibiotic dosing, and concomitant or subsequent superinfections. The diagnosis of antibiotic failure and distinguishing failure from superinfection or noninfectious mimics is difficult because clinical criteria alone are inadequate. Microbiologic response is accurate only if quantitative cultures are used. Biochemical markers may be more accurate than clinical but still don't discriminate between causes. The appropriate diagnostic strategy and treatment algorithms have not been fully addressed and more research is clearly needed.

Use of Broad-Spectrum Antimicrobials for the Treatment of Pneumonia in Seriously Ill Patients: Maximizing Clinical Outcomes and Minimizing Selection of Resistant Organisms

Among various risk factors for death among critically ill patients with serious infection, inappropriate antimicrobial therapy is an important factor that clinicians can modify directly. The presence of multidrug-resistant bacteria is the primary reason that patients with ventilator-associated pneumonia receive inappropriate antimicrobial therapy. Empirical antimicrobial therapy for ventilator-associated pneumonia should be initiated promptly and should have a broad spectrum that covers all potential antimicrobial-resistant pathogens. Delaying the start of therapy or modifying an inappropriate antimicrobial regimen does not improve outcome, probably because the change comes too late to redirect the course of illness. Timely empirical therapy with highly effective agents that are rapidly bactericidal could minimize the emergence of resistance. Broad-spectrum therapy should be streamlined (i.e., de-escalated), as appropriate, on the basis of microbiological data and clinical response. Switching to narrower-spectrum therapy that is directed by culture results may minimize the emergence of resistance. For some patients, clinical response will allow a shortening of the duration of antimicrobial therapy.

Microbiologic Diagnosis of Ventilator-Associated Pneumonia

No single test will provide all the information needed to diagnose ventilator-associated pneumonia (VAP), and the clinician must use multiple clinical criteria for the diagnosis. The use of culture techniques allows one to enhance the sensitivity and specificity of the diagnosis of pneumonia. In addition, the clinician can be kept up to date about potential new pathogens as they occur in the intensive care unit. Knowledge of the local flora allows one to make a better choice of empiric therapy for VAP.

Recent Trends in the Management of Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) occurs frequently in mechanically ventilated patients and has a high mortality rate. To date, there is no consensus for the diagnosis of VAP. Effective reduction in VAP-inducedmortality requires amultifaceted approach to include assessment of individual risks for VAP, implementation of effective ventilator handling procedures, routine use of VAP prevention strategies, appropriate use and interpretation of invasive and noninvasive diagnostic tests, and early broad spectrum antibiotic coverage with narrowing of coverage and cessation of therapy based on clinical improvement. Pharmacokinetic and pharmacodynamic principlesmust be used in designingempiric antibiotic regimens. Because an inappropriate empiric regimen in VAP has been associated with increasedmortality, it is imperative to maintain intensive care unit–specific epidemiologic data.

Diagnosis of ventilator-associated pneumonia

The diagnosis of ventilator pneumonia remains a controversial area. Use of standard clinical criteria has been found to be inadequate. Use of a clinical pulmonary infection score (CPIS) has improved the diagnostic utility of clinical criteria. For the intubated patient, there is ready access to the lower respiratory tract. Samples include endotracheal aspirates, bronchoalveolar lavage and protected brush specimen. The latter two can be obtained blindly or via a bronchoscope. The culture results are more meaningful if reported in a semi-quantitative model. There is increasing evidence that culture results predict mortality and can be used to direct duration and type of therapy.