Short course antibiotic therapy for Gram-negative hospital-acquired pneumonia in the critically ill

Antimicrobial stewardship in the intensive care unit

High resistance rates to antimicrobials continue to be a global health threat. The incidence of multidrug-resistant (MDR) microorganisms in intensive care units (ICUs) is quite high compared to in the community and other units in the hospital because ICU patients are generally older, have higher numbers of co-morbidities and immune-suppressed; moreover, the typically high rates of invasive procedures performed in the ICU increase the risk of infection by MDR microorganisms. Antimicrobial stewardship (AMS) refers to the implementation of coordinated interventions to improve and track the appropriate use of antibiotics while offering the best possible antibiotic prescription (according to dose, duration, and route of administration). Broad-spectrum antibiotics are frequently preferred in ICUs because of greater infection severity and colonization and infection by MDR microorganisms. For this reason, a number of studies on AMS in ICUs have increased in recent years. Reducing the use of broad-spectrum antibiotics forms the basis of AMS. For this purpose, parameters such as establishing an AMS team, limiting the use of broad-spectrum antimicrobials, terminating treatments early, using early warning systems, pursuing infection control, and providing education and feedback are used. In this review, current AMS practices in ICUs are discussed.

Duration of Antibiotic Therapy for Early VAP Trial: Study Protocol for a Surgical Infection Society Multicenter, Pragmatic, Randomized Clinical Trial of Four versus Seven Days of Definitive Antibiotic Therapy for Early Ventilator-Associated Pneumonia in Surgical Patients

Background: Current guidelines recommend a seven-day course of antibiotic therapy for patients with ventilator-associated pneumonia (VAP). However, clinical and microbiologic resolution of infection may occur much sooner than seven days, particularly in patients with early VAP. Shortening the course of antibiotic therapy for early VAP likely results in lower antibiotic-associated complications, but it is unclear whether VAP recurrence rates will be higher in patients receiving fewer days of therapy. We propose to compare four days versus seven days of antibiotic therapy for early VAP in surgical patients in a multicenter, pragmatic, randomized clinical trial. Patients and Methods: Eligible patients admitted to a surgical intensive care unit with early VAP, defined as VAP occurring within two to seven days of intubation, will be randomized to receive four or seven days of antibiotic therapy. The two primary outcomes are: VAP recurrence, defined as VAP occurring two to 14 days after completion of initial therapy and antibiotic-free days, defined as the number of days without receiving any antibiotic agents within 30 days from completion of initial therapy. Data will be analyzed using both intention-to-treat and per-protocol strategies. Power analysis was performed assuming non-inferiority of four days vs. seven days for VAP recurrence and superiority of four days versus seven days for antibiotic-free days. The total sample size to detect a 10% difference between groups with 80% power and assuming a 10% dropout rate is 458 patients. Three separate data analyses are planned throughout the trial and sample size will be re-calculated at each interim analysis. Conclusions: The Duration of Antibiotic Therapy for Early VAP (DATE) Trial will enroll surgical patients with early VAP to analyze whether a shorter duration of antibiotic therapy results in similar clinical outcomes while decreasing antibiotic exposure.

Clinical pulmonary infection score and a spot serum procalcitonin level to guide discontinuation of antibiotics in ventilator-associated pneumonia: a study in a single institution with high prevalence of nonfermentative gram-negative bacilli infection

Background

We wanted to determine the impact of combined Clinical Pulmonary Infection Score (CPIS) and a spot serum procalcitonin (PCT)-guided protocol to shorten the duration of antibiotic treatment in patients with ventilator-associated pneumonia (VAP), mainly caused by nonfermentative gram-negative bacilli (NF-GNB).

Methods

Patients with VAP who received appropriate antibiotics for 7 days, temperature ⩽ 37.8°C, without shock, and CPIS ⩽ 6 were allocated to the PCT group or conventional group according to the treating physicians’ decisions. In the PCT group, antibiotics were stopped if the PCT level on day 8 < 0.5 ng/ml. In the conventional group, antibiotics were stopped according to physicians’ discretion.

Results

There were 24 patients in the PCT group and 26 patients in the conventional group. NF-GNB were responsible for VAP in 79.2% of the PCT group and 65.4% of the conventional group. PCT group had a greater number of antibiotic-free days alive during the 28 days after VAP onset than the conventional group (14.6 ± 5.4 days versus 5.9 ± 5.7 days, respectively; p <.001). In the multivariate, propensity score-adjusted analysis, the PCT group [coefficient = −9.1 (–12.2 to −6); p <.001] and extrapulmonary infections [coefficient = 6.4 (3.3–9.5); p <.001] were independent predictors of total antibiotic exposure days. There was no relapse in both groups. Meanwhile, 12.5% of the PCT group and 26.9% of the conventional group subsequently developed recurrent VAP compatible with superinfections.

Conclusions

CPIS and a spot serum PCT level appeared effective and safe to guide discontinuation of antibiotic treatment in patients with VAP caused by NF-GNB.

Trial registration:

TCTR20160726002

Antibiotic Use in the Intensive Care Unit: Optimization and De-Escalation

Appropriate antimicrobial therapy is essential to ensuring positive patient outcomes. Inappropriate or suboptimal utilization of antibiotics can lead to increased length of stay, multidrug-resistant infections, and mortality. Critically ill intensive care patients, particularly those with severe sepsis and septic shock, are at risk of antibiotic failure and secondary infections associated with incorrect antibiotic use. Through the initiation of active empiric antibiotic therapy based upon local susceptibilities, daily evaluation of signs and symptoms of infection and narrowing of antibiotic therapy when feasible, providers can streamline the treatment of common intensive care unit (ICU) infections. Optimizing antibiotic dosing through prolonged infusions can be beneficial in intensive care populations with altered pharmacokinetics. Antimicrobial stewardship teams can assist ICU providers in managing and implementing these tactics. This review will discuss the current literature on antibiotic use in the ICU applying antimicrobial stewardship strategies. Based upon the most recent evidence, ICUs would benefit from employing empiric guidelines for antibiotic use, collecting appropriate specimens and implementing molecular diagnostics, optimizing the dosing of antibiotics, and reducing the duration of total therapy. These strategies for antibiotic use have the potential to enhance patient care while preventing adverse outcomes.

Tackling Threats and Future Problems of Multidrug-Resistant Bacteria

With the advent of the antibiotic era, the overuse and inappropriate consumption and application of antibiotics have driven the rapid emergence of multidrug-resistant pathogens. Antimicrobial resistance increases the morbidity, mortality, length of hospitalization and healthcare costs. Among Gram-positive bacteria, Staphylococcus aureus (MRSA) and multidrug-resistant (MDR) Mycobacterium tuberculosis, and among the Gram-negative bacteria, extended-spectrum beta-lactamase (ESBLs)-producing bacteria have become a major global healthcare problem in the 21st century. The pressure to use antibiotics guarantees that the spread and prevalence of these as well as of future emerging multidrug-resistant pathogens will be a persistent phenomenon. The unfeasibility of reversing antimicrobial resistance back towards susceptibility and the critical need to treat bacterial infection in modern medicine have burdened researchers and pharmaceutical companies to develop new antimicrobials effective against these difficult-to-treat multidrug-resistant pathogens. However, it can be anticipated that antibiotic resistance will continue to develop more rapidly than new agents to treat these infections become available and a better understanding of the molecular, evolutionary and ecological mechanisms governing the spread of antibiotic resistance is needed. The only way to curb the current crisis of antimicrobial resistance will be to develop entirely novel strategies to fight these pathogens such as combining antimicrobial drugs with other agents that counteract and obstruct the antibiotic resistant mechanisms expressed by the pathogen. Furthermore, as many antibiotics are often inappropriately prescribed, a more personalized approach based on precise diagnosis tools will ensure that proper treatments can be promptly applied leading to more targeted and effective therapies. However, in more general terms, also the overall use and release of antibiotics in the environment needs to be better controlled.

Shortening the course of antibiotic treatment in the intensive care unit

Effective antimicrobial stewardship is an increasingly important concern for healthcare providers globally. Antibiotics are frequently prescribed for patients who develop sepsis in the intensive care unit and traditionally courses are prolonged, with uncertain benefit and probable harm. There is little evidence to support many guidelines recommending between 10 and 14 days, and a number of studies suggest substantially shorter courses of less than 7 days may suffice. Safely reducing course length is likely to depend on a number of preconditions, including thorough eradication of any septic foci; optimization of serum antibiotic concentrations, particularly when there is physiological derangement; and use of novel biomarkers such as procalcitonin. The critical care environment is well suited to this aim as patients are closely monitored. With these measures in place, it is reasonable to believe short antibiotic courses can safely be used for the majority of intensive care infections.

Assessment of the intensive care unit treatment of pneumonia at a veterans affairs facility

INTRODUCTION

Pneumonia is a common cause of morbidity and mortality in the critically ill. Clinicians use a range of duration for antibiotic treatment from 7 to 14 days or longer. Failure to de-escalate antimicrobial therapy in a timely manner may lead to increased antimicrobial resistance, increased risk of side effects, and increased cost.

OBJECTIVE

To investigate potential methods to improve treatment of pneumonia for patients in 4 intensive care units (ICUs).

METHODS

A retrospective descriptive chart review was conducted at the Veterans Affairs North Texas Health Care System (VANTHCS). Veterans aged 18 to 90 years admitted to the ICU with a diagnosis of pneumonia were included. Descriptive statistics were used to interpret the data. Current management was reviewed to identify markers such as length of antibiotic therapy, ICU length of stay, and inpatient mortality. Secondary objectives included appropriateness and accuracy of the empiric regimen.

RESULTS

Of the 1,854 Veterans admitted, 107 met inclusion criteria. Antibiotic choices for positive cultures were appropriate in 45 out of 46 (98%) patients, with an average length of therapy of 8.6 ± 6.3 days. De-escalation of antibiotics based on sensitivity data occurred in 73% of positive cultures.

CONCLUSIONS

Pneumonia in the VANTHCS ICUs is initially treated with empiric antibiotics. Empiric antibiotic therapy for pneumonia was appropriate and accurate over this time period. Opportunities exist for de-escalation in patients with or without positive cultures. The procalcitonin assay is now being utilized at VANTHCS to optimize patient care.

Early-onset ventilator-associated pneumonia in adults randomized clinical trial: comparison of 8 versus 15 days of antibiotic treatment

PURPOSE

The optimal treatment duration for ventilator-associated pneumonia is based on one study dealing with late-onset of the condition. Shortening the length of antibiotic treatment remains a major prevention factor for the emergence of multiresistant bacteria.

OBJECTIVE

To demonstrate that 2 different antibiotic treatment durations (8 versus 15 days) are equivalent in terms of clinical cure for early-onset ventilator-associated pneumonia.

METHODS

Randomized, prospective, open, multicenter trial carried out from 1998 to 2002.

MEASUREMENTS

The primary endpoint was the clinical cure rate at day 21. The mortality rate was evaluated on days 21 and 90.

RESULTS

225 patients were included in 13 centers. 191 (84.9%) patients were cured: 92 out of 109 (84.4%) in the 15 day cohort and 99 out of 116 (85.3%) in the 8 day cohort (difference = 0.9%, odds ratio = 0.929). 95% two-sided confidence intervals for difference and odds ratio were [-8.4% to 10.3%] and [0.448 to 1.928] respectively. Taking into account the limits of equivalence (10% for difference and 2.25 for odds ratio), the objective of demonstrative equivalence between the 2 treatment durations was fulfilled. Although the rate of secondary infection was greater in the 8 day than the 15 day cohort, the number of days of antibiotic treatment remained lower in the 8 day cohort. There was no difference in mortality rate between the 2 groups on days 21 and 90.

CONCLUSION

Our results suggest that an 8-day course of antibiotic therapy is safe for early-onset ventilator-associated pneumonia in intubated patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01559753.

Clinical experience of tigecycline treatment in infections caused by extensively drug-resistant Acinetobacter spp

BACKGROUND

Tigecycline has broad spectrum antimicrobial activity and is approved for complicated intra-abdominal infections, complicated skin and soft tissue infections, and community-acquired pneumonia. There are few data on clinical experience of tigecycline in hospital-acquired pneumonia (HAP) and Acinetobacter spp. infection.

METHODS

A retrospective study was performed at eight hospitals in Korea from May 2009 to January 2010. Adult patients treated with tigecycline regardless of their source of infection or pathogens were enrolled.

RESULTS

Tigecycline was administered in 108 patients. Pneumonia was the most common infection (43.5%), followed by skin and soft tissue infections (20.4%). Acinetobacter baumannii was isolated from 83 patients (76.9%) accounting for 50.3% of isolated pathogens, showing a resistance rate of 67.5% to carbapenems. Superinfection was identified in 32 patients (29.6%). Pseudomonas aeruginosa was most common microorganism causing superinfection (46.9%). Overall 30-day mortality rate was 52.9%. Thirty-day mortality rate of HAP and Acinetobacter spp. infection was 60.5% and 59.4%, respectively.

CONCLUSION

Tigecycline can be considered as an alternative therapy in patients with HAP or infections caused by Acinetobacter spp., especially extensively drug-resistant A. baumannii.

Impact of a guideline on management of children hospitalized with community-acquired pneumonia

OBJECTIVES

We sought to describe the impact a clinical practice guideline (CPG) had on antibiotic management of children hospitalized with community-acquired pneumonia (CAP).

PATIENTS AND METHODS

We conducted a retrospective study of discharged patients from a children's hospital with an ICD-9-CM code for pneumonia (480-486). Eligible patients were admitted from July 8, 2007, through July 9, 2009, 12 months before and after the CAP CPG was introduced. Three-stage least squares regression analyses were performed to examine hypothesized simultaneous relationships, including the impact of our institution\x{2019}s antimicrobial stewardship program (ASP).

RESULTS

The final analysis included 1033 patients: 530 (51%) before the CPG (pre-CPG) and 503 (49%) after the CPG (post-CPG). Pre-CPG, ceftriaxone (72%) was the most commonly prescribed antibiotic, followed by ampicillin (13%). Post-CPG, the most common antibiotic was ampicillin (63%). The effect of the CPG was associated with a 34% increase in ampicillin use (P < .001). Discharge antibiotics also changed post-CPG, showing a significant increase in amoxicillin use (P < .001) and a significant decrease in cefdinir and amoxicillin/clavulanate (P < .001), with the combined effect of the CPG and ASP leading to 12% (P < 0.001) and 16% (P < .001) reduction, respectively. Overall, treatment failure was infrequent (1.5% vs 1%).

CONCLUSIONS

A CPG and ASP led to the increase in use of ampicillin for children hospitalized with CAP. In addition, less broad-spectrum discharge antibiotics were used. Patient adverse outcomes were low, indicating that ampicillin is appropriate first-line therapy for otherwise healthy children admitted with uncomplicated CAP.

Dosing regimen matters: the importance of early intervention and rapid attainment of the pharmacokinetic/pharmacodynamic target

To date, the majority of pharmacokinetic/pharmacodynamic (PK/PD) discussions have focused on PK/PD relationships evaluated at steady-state drug concentrations. However, a concern with reliance upon steady-state drug concentrations is that it ignores events occurring while the pathogen is exposed to intermittent suboptimal systemic drug concentrations prior to the attainment of a steady state. Suboptimal (inadequate) exposure can produce amplification of resistant bacteria. This minireview provides an overview of published evidence supporting the positions that, in most situations, it is the exposure achieved during the first dose that is relevant for determining the therapeutic outcome of an infection, therapeutic intervention should be initiated as soon as possible to minimize the size of the bacterial burden at the infection site, and the duration of drug administration should be kept as brief as clinically appropriate to reduce the risk of selecting for resistant (or phenotypically nonresponsive) microbial strains. To support these recommendations, we briefly discuss data on inoculum effects, persister cells, and the concept of time within some defined mutation selection window.

Duration and cessation of antimicrobial treatment

Shortening the duration of antimicrobial therapy is an important strategy for optimizing patient care and reducing the spread of antimicrobial resistance. It is best used in the context of an overall approach to infection management that includes a focus on selecting the right initial drug and dosing regimen for empiric therapy, and de-escalation to a more narrowly focused drug regimen (or termination) based on subsequent culture results and clinical data. In addition to reducing resistance, other potential benefits of shorter antimicrobial courses include lowered antimicrobial costs, reduced risk of superinfections (including Clostridium difficile-associated diarrhea), reduced risk of antimicrobial-related organ toxicity, and improved drug compliance. There have been relatively few randomized clinical trials that study the optimal treatment durations for such serious infections as pneumonia (community- and healthcare/hospital-acquired), complicated intra-abdominal infection, and catheter-related bloodstream infection (CRBSI). Nonetheless, a growing number of studies have explored the possibilities of reducing the duration of antimicrobial therapy for at least certain patients with these infections, under certain circumstances. Professional organizations have compiled these data and used them to develop clinical practice guidelines to aid clinicians in choosing optimal treatment durations for individual patients. Many patients with hospital-acquired pneumonia, ventilator-associated pneumonia, or healthcare-associated pneumonia can be treated for 7-8 days, while 4-7 days and 14-day treatment durations may suffice for many patients with complicated intra-abdominal infections and uncomplicated CRBSI, respectively. This article first provides a general background on the rationale and data supporting shortened courses of antimicrobial therapy, before using 3 case studies to explore the practical implications of current knowledge and treatment guidelines when making decisions about treatment duration for individual patients with healthcare-associated pneumonia, complicated intra-abdominal infection, and CRBSI.