Outcomes Associated With De-escalating Therapy for Methicillin-Resistant Staphylococcus aureus in Culture-Negative Nosocomial Pneumonia

Using Methicillin-Resistant Staphylococcus aureus Nasal Screens to Rule Out Methicillin-Resistant S aureus Pneumonia in Surgical Intensive Care Units

INTRODUCTION

The methicillin-resistant Staphylococcus aureus (MRSA) polymerase chain reaction (PCR) has a high negative predictive value (NPV). We aimed to understand if there was a difference in the NPV of the MRSA screen in surgical intensive care units (ICUs) and to determine its role in antibiotic de-escalation.

METHODS

We performed a single-center, retrospective cohort study of adults with a positive respiratory culture and MRSA nasal PCR admitted to a surgical ICU from 2016 to 2019. Patients were stratified by surgical ICU: cardiothoracic/cardiovascular intensive care unit (CVICU) or transplant/acute care surgery intensive care unit (ACS-ICU). Our primary outcome was the NPV of MRSA screen. Secondary outcome was the duration of empiric MRSA-targeted therapy.

RESULTS

We analyzed 61 patients: 42.6% (n = 26) ACS-ICU and 57.4% (n = 35) CVICU. There were no differences in age, comorbidities, prior MRSA infection, recent antibiotic use, immunocompromised status, or renal replacement therapy. At pneumonia diagnosis, more patients in the ACS-ICU were hospitalized ≥5 d (65.4% versus 8.6%, P < 0.0001) and more patients in the CVICU were in septic shock (88.6% versus 34.5%, P < 0.0001) and thrombocytopenic (40% versus 11.5%, P = 0.02). NPV of the PCR was similar (ACS-ICU: 0.92 [0.75-0.98], CV-ICU 0.89 [0.73-0.96]). On multivariable linear regression, the CVICU was associated with longer empiric therapy (β 1.5, 95% CI 0.8-2.3, P < 0.0001), as was hospitalization for ≥5 d (β 0.73, 95% CI 0.06-1.39, P = 0.03).

CONCLUSIONS

The MRSA nasal PCR screen has a high NPV for ruling out MRSA pneumonia in critically ill surgical patients. However, patients in the CVICU and patients hospitalized ≥5 d had a longer time to de-escalation of MRSA-targeted therapy, potentially due to higher clinical risk profile.

Management of Sepsis and Septic Shock: What Have We Learned in the Last Two Decades?

Sepsis is a clinical syndrome encompassing physiologic and biological abnormalities caused by a dysregulated host response to infection. Sepsis progression into septic shock is associated with a dramatic increase in mortality, hence the importance of early identification and treatment. Over the last two decades, the definition of sepsis has evolved to improve early sepsis recognition and screening, standardize the terms used to describe sepsis and highlight its association with organ dysfunction and higher mortality. The early 2000s witnessed the birth of early goal-directed therapy (EGDT), which showed a dramatic reduction in mortality leading to its wide adoption, and the surviving sepsis campaign (SSC), which has been instrumental in developing and updating sepsis guidelines over the last 20 years. Outside of early fluid resuscitation and antibiotic therapy, sepsis management has transitioned to a less aggressive approach over the last few years, shying away from routine mixed venous oxygen saturation and central venous pressure monitoring and excessive fluids resuscitation, inotropes use, and red blood cell transfusions. Peripheral vasopressor use was deemed safe and is rising, and resuscitation with balanced crystalloids and a restrictive fluid strategy was explored. This review will address some of sepsis management's most important yet controversial components and summarize the available evidence from the last two decades.

The impact of antimicrobial de-escalation therapy in culture-negative pneumonia: a systematic review and meta-analysis

BACKGROUND/AIMS

Antimicrobial de-escalation (ADE) remains a challenging strategy in the treatment of pneumonia. We investigated the outcomes of ADE as measured by mortality and duration of the use of antibiotics in patients with culture- negative pneumonia.

METHODS

We performed a systematic review and meta-analysis in accordance with PRISMA guidelines. The primary outcome was inpatient mortality.

RESULTS

We examined six studies comprising 11,933 subjects, of whom 1,152 received ADE. Overall, the ADE strategy was associated with a statistically lower risk of in-hospital mortality compared with non-ADE (risk ratio [RR] = 0.60, 95% confidence interval [CI] = 0.38 to 0.93). Although substantial heterogeneity was found among the included studies (I2 = 66%), a meta-regression analysis could not reveal plausible sources of heterogeneity. And ADE was associated with a shorter duration of total and initial antibiotic therapies and total length of hospital stay compared with non-ADE.

CONCLUSION

Our findings suggest that ADE seems to be significantly associated with better clinical outcomes compared with non-ADE. Caution is demanded when interpreting data of this study because of substantial between-study heterogeneity.

Effect of antimicrobial de-escalation strategy on 14-day mortality among intensive care unit patients: a retrospective propensity score-matched cohort study with inverse probability-of-treatment weighting

PURPOSE

This study aimed to investigate the prevalence of antimicrobial de-escalation (ADE) strategy and assess its effect on 14-day mortality among intensive care unit patients.

METHODS

A single-center retrospective cohort study was conducted on patients admitted to the intensive care unit (ICU) with infectious diseases between January 2018 and December 2020. Patients were stratified into three groups based on the initial treatment regimen within 5 days of antimicrobial administration: ADE, No Change, and Other Change. Confounders between groups were screened using one-way ANOVA and Chi-square analysis. Univariate and multivariate analyses were performed to identify risk factors for 14-day mortality. Potential confounders were balanced using propensity score inverse probability of treatment weighting (IPTW), followed by multivariate logistic regression analysis to evaluate the effect of ADE strategy on 14-day mortality.

RESULTS

A total of 473 patients met the inclusion criteria, with 53 (11.2%) in the ADE group, 173 (36.6%) in the No Change group, and 247 (52.2%) in the Other Change group. The 14-day mortality rates in the three groups were 9.4%, 11.6%, and 21.9%, respectively. After IPTW, the adjusted odds ratio for 14-day mortality comparing No Change with ADE was 1.557 (95% CI 1.078-2.247, P = 0.0181) while comparing Other Change with ADE was 1.282(95% CI 0.884-1.873, P = 0.1874).

CONCLUSION

The prevalence of ADE strategy was low among intensive care unit patients. The ADE strategy demonstrated a protective effect or no adverse effect on 14-day mortality compared to the No Change or Other Change strategies, respectively. These findings provide evidence supporting the implementation of the ADE strategy in ICU patients.

Performance of Methicillin-Resistant Staphylococcus aureus Polymerase Chain Reaction Nasal Screening for Ruling Out MRSA Pneumonia in Hospitalized, Immunocompromised Patients

Background: Recent literature demonstrates support for using methicillin-resistant Staphylococcus aureus (MRSA) nasal swab polymerase chain reaction (NaPCR) screening as an antimicrobial stewardship tool aiding early de-escalation of anti-MRSA antimicrobials. However, immunocompromised patients have been underrepresented in previous studies despite increased risk of morbidity and mortality from multidrug-resistant organisms (MDRO). Objective: The purpose of this study was to determine the negative predictive value (NPV) of the MRSA NaPCR in hospitalized, immunocompromised adult patients with suspected pneumonia. Methods: A single-center, retrospective, observational review was conducted of hospitalized, immunocompromised adult patients that had an MRSA NaPCR obtained between March 1, 2020 and January 10, 2021. For inclusion, bacterial cultures must have been collected within 2 weeks after MRSA NaPCR. The primary outcome was the NPV of MRSA NaPCR in hospitalized, immunocompromised patients with suspected pneumonia. Secondary outcomes include NPV in other infections. Results: Between March 1, 2020 and January 10, 2021, 59 patients with 78 unique cultures, including 28 respiratory cultures, were included in the study. The NPV of the MRSA NaPCR for pneumonia was 91.7%. The NPV for bloodstream infections was 100% and for urinary tract infections was 100%, but interpretation of these results should be cautioned due to the small sample sizes. Conclusion: The NPV of MRSA NaPCR in pneumonia remains high in this study. The MRSA NaPCR has utility as a de-escalation tool in hospitalized, immunocompromised adult patients, but larger studies are warranted to evaluate all immunocompromised patient populations.

Antibiotic stewardship in the ICU: time to shift into overdrive

Antibiotic resistance is a major health problem and will be probably one of the leading causes of deaths in the coming years. One of the most effective ways to fight against resistance is to decrease antibiotic consumption. Intensive care units (ICUs) are places where antibiotics are widely prescribed, and where multidrug-resistant pathogens are frequently encountered. However, ICU physicians may have opportunities to decrease antibiotics consumption and to apply antimicrobial stewardship programs. The main measures that may be implemented include refraining from immediate prescription of antibiotics when infection is suspected (except in patients with shock, where immediate administration of antibiotics is essential); limiting empiric broad-spectrum antibiotics (including anti-MRSA antibiotics) in patients without risk factors for multidrug-resistant pathogens; switching to monotherapy instead of combination therapy and narrowing spectrum when culture and susceptibility tests results are available; limiting the use of carbapenems to extended-spectrum beta-lactamase-producing Enterobacteriaceae, and new beta-lactams to difficult-to-treat pathogen (when these news beta-lactams are the only available option); and shortening the duration of antimicrobial treatment, the use of procalcitonin being one tool to attain this goal. Antimicrobial stewardship programs should combine these measures rather than applying a single one. ICUs and ICU physicians should be at the frontline for developing antimicrobial stewardship programs.

Determinants of Mortality for Ventilated Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia

Hospital-acquired pneumonia (HAP) is the most common hospital-acquired infection, accounting for 22% of all nosocomial infections. The available studies to date have not attempted to assess whether confounding factors may account for the observed difference in mortality for the two forms of nosocomial pneumonia associated with mechanical ventilation, namely ventilated HAP (vHAP) and ventilator-associated pneumonia (VAP).

OBJECTIVES

To determine if vHAP is an independent predictor of mortality among patients with nosocomial pneumonia.

DESIGN SETTING AND PARTICIPANTS

Single-center retrospective cohort study conducted at Barnes-Jewish Hospital, St. Louis, MO, between 2016 and 2019. Adult patients with a pneumonia discharge diagnosis were screened and patients diagnosed with vHAP and VAP were included. All patient data was extracted from the electronic health record.

MAIN OUTCOMES AND MEASURES

The primary outcome was 30-day all-cause mortality (ACM).

RESULTS

One thousand one-hundred twenty unique patient admissions were included (410 vHAP, 710 VAP). Thirty-day ACM was greater for patients with vHAP compared with VAP (37.1% vs 28.5%; p = 0.003). Logistic regression analysis identified vHAP (adjusted odds ratio [AOR], 1.77; 95% CI, 1.51-2.07), vasopressor use (AOR, 2.34; 95% CI, 1.94-2.82), Charlson Comorbidity Index (1-point increments) (AOR, 1.21; 95% CI, 1.18-1.24), total antibiotic treatment days (1-d increments) (AOR, 1.13; 95% CI, 1.11-1.14), and Acute Physiology and Chronic Health Evaluation II score (1-point increments) (AOR, 1.04; 95% CI, 1.03-1.06) as independent predictors of 30-day ACM. The most common bacterial pathogens identified as causes of vHAP and VAP were Staphylococcus aureus, Enterobacterales species, and Pseudomonas aeruginosa.

CONCLUSIONS AND RELEVANCE

In this single-center cohort study with low rates of initial inappropriate antibiotic therapy, vHAP had greater 30-day ACM compared with VAP after adjusting for potential confounding variables including disease severity and comorbidities. This finding suggests that clinical trials enrolling patients with vHAP need to account for this outcome difference in their trial design and data interpretation.

Spectrum scores: Toward a better definition of de-escalation

Spectrum scores measure antimicrobial utilization while also quantifying the spectrum of activity. Accordingly, changes in spectrum score can be used to identify antimicrobial de-escalation. We show that spectrum-score–based de-escalation has a 95.7% positive percentage agreement and 81.6% negative percentage agreement versus de-escalation defined as stopping either antistaphylococcal or antipseudomonal agents.

Antimicrobial safety considerations in critically ill patients: part I: focused on acute kidney injury

INTRODUCTION

Antibiotic prescription is a challenging issue in critical care settings. Different pharmacokinetic and pharmacodynamic properties, polypharmacy, drug interactions, and high incidence of multidrug-resistant microorganisms in this population can influence the selection, safety, and efficacy of prescribed antibiotics.

AREAS COVERED

In the current article, we searched PubMed, Scopus, and Google Scholar for estimating renal function in acute kidney injury, nephrotoxicity of commonly used antibiotics, and nephrotoxin stewardship in intensive care units.

EXPERT OPINION

Early estimation of kidney function with an accurate method may be helpful to optimize antimicrobial treatment in critically ill patients. Different antibiotic dosing regimens may be required for patients with acute kidney injury. In many low-resource settings, therapeutic drug monitoring is not available for antibiotics. Acute kidney injury may influence treatment effectiveness and patient outcome.

Evaluation of the Negative Predictive Value of Methicillin-Resistant Staphylococcus aureus Nasal Swab Screening in the Medical Intensive Care Units and Its Effect on Antibiotic Duration

Background

In addition to active surveillance of methicillin-resistant Staphylococcus aureus (MRSA) carrier, MRSA nasal screening can be valuable for antibiotic de-escalation. This study aimed to assess the correlations between the MRSA nasal swab and subsequent culture results in patients admitted to medical intensive care units (MICU). The impact of MRSA nasal swab on the antibiotic duration was also evaluated.

Materials and Methods

This retrospective study enrolled patients who received glycopeptides in the MICU of a medical center in 2019. Patients treated with glycopeptides for over 2 days before MICU admission were excluded. The associated data were collected through the electronic medical record system. The negative predictive value (NPV) of MRSA nasal swabs for MRSA infection was calculated, and their influence on empirical glycopeptide treatment duration was analyzed.

Results

Of the 338 patients who met the inclusion criteria, 277 underwent MRSA nasal screening. The NPV of MRSA-negative nasal swab for subsequent MRSA infection was 98.4%. The glycopeptide treatment duration of the patients with and without nasal screening was not significantly different (4.2 ± 2.8 vs 4.4 ± 3.0 days, p = 0.577). Of the 120 patients with MRSA-negative nasal swab and no subsequent MRSA infection, 75 continued empirical glycopeptides therapy. The additional treatment time was 3 days (interquartile range: 2–6 days).

Conclusion

The MRSA nasal swabs have high NPV for MRSA infection in critically ill patients. However, it has no impact on the empirical glycopeptide treatment duration. The value of MRSA nasal swabs should be advocated to optimize antibiotic therapy.

Assessment of Antibiotic De-escalation by Spectrum Score in Patients With Nosocomial Pneumonia: A Single-Center, Retrospective Cohort Study

BACKGROUND

Hospital-acquired and ventilator-associated pneumonia (HAP/VAP) cause significant mortality. Guidelines recommend empiric broad-spectrum antibiotics followed by de-escalation (DE). This study sought to assess the impact of DE on treatment failure.

METHODS

This single-center retrospective cohort study screened all adult patients with a discharge diagnosis code for pneumonia from 2016 to 2019. Patients were enrolled if they met predefined criteria for HAP/VAP ≥48 hours after admission. Date of pneumonia diagnosis was defined as day 0. Spectrum scores were calculated, and DE was defined as a score reduction on day 3 versus day 1. Patients with DE were compared to patients with no de-escalation (NDE). The primary outcome was composite treatment failure, defined as all-cause mortality or readmission for pneumonia within 30 days of diagnosis.

RESULTS

Of 11860 admissions screened, 1812 unique patient-admissions were included (1102 HAP, 710 VAP). Fewer patients received DE (876 DE vs 1026 NDE). Groups were well matched at baseline, although more patients receiving DE had respiratory cultures ordered (56.6% vs 50.6%, P = .011). There was no difference in composite treatment failure (35.0% DE vs 33.8% NDE, P = .604). De-escalation was not associated with treatment failure on multivariable Cox regression analysis (hazard ratio, 1.13; 95% confidence interval, 0.96-1.33). Patients receiving DE had fewer antibiotic days (median 9 vs 11, P < .0001), episodes of Clostridioides difficile infection (2.2% vs 3.8%, P = .046), and hospital days (median 20 vs 22 days, P = .006).

CONCLUSIONS

De-escalation and NDE resulted in similar rates of 30-day treatment failure; however, DE was associated with fewer antibiotic days, episodes of C difficile infection, and days of hospitalization.

Comparative incidence of acute kidney injury in patients on vancomycin therapy in combination with cefepime, piperacillin-tazobactam or meropenem

Recent studies have shown that the incidence of nephrotoxicity increases when vancomycin is combined with a beta-lactam antibiotic. The objective of this study was to compare the incidence of acute kidney injury (AKI) in adult patients who received vancomycin with either piperacillin-tazobactam (VPT), cefepime (VC), or meropenem (VM). This was a single center retrospective chart review. Patients were included if they were 18 years or older, received 48 hours of combination therapy and antibiotics were started within 24 hours of each other. Exclusion criteria were receiving more than one combination of antibiotics, serum creatinine > 1.2 mg/dL, AKI at the time of inclusion, or any form of renal replacement therapy. Two hundred patients met inclusion criteria. A total of 27 (13%) patients experienced AKI. The incidence of AKI was 21.6%, 9%, and 7.4% in the VPT, VC and VM groups, respectively. A patient who received VPT was 5 times more likely to develop AKI when compared to a patient who received VC (adjusted OR 5.09 95% CI (1.51-17.08), p = 0.008) and 7 times more likely to develop AKI when compared to VM (adjusted OR 7.03 95% CI (1.97-28.08), p = 0.002). This study found a statistically significant difference in the incidence of AKI in patient receiving VPT when compared to VC or VM. This finding supports the need for careful monitoring of renal function in patients receiving VPT therapy and routine evaluation for de-escalation of antimicrobial therapy.

Vancomycin Advanced Therapeutic Drug Monitoring: Exercise in Futility or Virtuous Endeavor to Improve Drug Efficacy and Safety?

Vancomycin is commonly prescribed to hospitalized patients. Decades of pharmacokinetic/pharmacodynamic research culminated in recommendations to monitor the ratio of the area under the concentration-time curve (AUC) to the minimum inhibitory concentration in order to optimize vancomycin exposure and minimize toxicity in the revised 2020 guidelines. These guideline recommendations are based on limited data without high-quality evidence and limitations in strength. Despite considerable effort placed on vancomycin therapeutic drug monitoring (TDM), clinicians should recognize that the majority of vancomycin use is empiric. Most patients prescribed empiric vancomycin do not require it beyond a few days. For these patients, AUC determinations during the initial days of vancomycin exposure are futile. This added workload may detract from high-level patient care activities. Loading doses likely achieve AUC targets, so AUC monitoring after a loading dose is largely unnecessary for broad application. The excessive vancomycin TDM for decades has been propagated with limitations in evidence, and it should raise caution on contemporary vancomycin TDM recommendations.

De-escalation of Empiric Antibiotics Following Negative Cultures in Hospitalized Patients With Pneumonia: Rates and Outcomes

BACKGROUND

For patients at risk for multidrug-resistant organisms, IDSA/ATS guidelines recommend empiric therapy against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas. Following negative cultures, the guidelines recommend antimicrobial de-escalation. We assessed antibiotic de-escalation practices across hospitals and their associations with outcomes in hospitalized patients with pneumonia with negative cultures.

METHODS

We included adults admitted with pneumonia in 2010-2015 to 164 US hospitals if they had negative blood and/or respiratory cultures and received both anti-MRSA and antipseudomonal agents other than quinolones. De-escalation was defined as stopping both empiric drugs on day 4 while continuing another antibiotic. Patients were propensity adjusted for de-escalation and compared on in-hospital 14-day mortality, late deterioration (ICU transfer), length-of-stay (LOS), and costs. We also compared adjusted outcomes across hospital de-escalation rate quartiles.

RESULTS

Of 14 170 patients, 1924 (13%) had both initial empiric drugs stopped by hospital day 4. Hospital de-escalation rates ranged from 2-35% and hospital de-escalation rate quartile was not significantly associated with outcomes. At hospitals in the top quartile of de-escalation, even among patients at lowest risk for mortality, the de-escalation rates were <50%. In propensity-adjusted analysis, patients with de-escalation had lower odds of subsequent transfer to ICU (adjusted odds ratio, .38; 95% CI, .18-.79), LOS (adjusted ratio of means, .76; .75-.78), and costs (.74; .72-.76).

CONCLUSIONS

A minority of eligible patients with pneumonia had antibiotics de-escalated by hospital day 4 following negative cultures and de-escalation rates varied widely between hospitals. To adhere to recent guidelines will require substantial changes in practice.

Antibiotic Stewardship in the Intensive Care Unit. An Official American Thoracic Society Workshop Report in Collaboration with the AACN, CHEST, CDC, and SCCM

Intensive care units (ICUs) are an appropriate focus of antibiotic stewardship program efforts because a large proportion of any hospital’s use of parenteral antibiotics, especially broad-spectrum, occurs in the ICU. Given the importance of antibiotic stewardship for critically ill patients and the importance of critical care practitioners as the front line for antibiotic stewardship, a workshop was convened to specifically address barriers to antibiotic stewardship in the ICU and discuss tactics to overcome these. The working definition of antibiotic stewardship is “the right drug at the right time and the right dose for the right bug for the right duration.” A major emphasis was that antibiotic stewardship should be a core competency of critical care clinicians. Fear of pathogens that are not covered by empirical antibiotics is a major driver of excessively broad-spectrum therapy in critically ill patients. Better diagnostics and outcome data can address this fear and expand efforts to narrow or shorten therapy. Greater awareness of the substantial adverse effects of antibiotics should be emphasized and is an important counterargument to broad-spectrum therapy in individual low-risk patients. Optimal antibiotic stewardship should not focus solely on reducing antibiotic use or ensuring compliance with guidelines. Instead, it should enhance care both for individual patients (by improving and individualizing their choice of antibiotic) and for the ICU population as a whole. Opportunities for antibiotic stewardship in common ICU infections, including community- and hospital-acquired pneumonia and sepsis, are discussed. Intensivists can partner with antibiotic stewardship programs to address barriers and improve patient care.

Strategies for prediction of drug-resistant pathogens and empiric antibiotic selection in community-acquired pneumonia

PURPOSE OF REVIEW

Although most patients with community-acquired pneumonia (CAP) are appropriately treated with narrow-spectrum antibiotics, predicting which patients require coverage of drug-resistant pathogens (DRP) remains a challenge. The 2019 American Thoracic Society/Infectious Diseases Society of America CAP guidelines endorse using locally validated prediction models for DRP. Here we review risk factors for DRP and provide a summary of available risk prediction models.

RECENT FINDINGS

Both inadequate initial empiric spectrum as well as unnecessary broad-spectrum antibiotic use are associated with poor outcomes in CAP. Multiple prediction models for DRP-based patient-level risk factors have been published, with some variation in included predictor variables and test performance characteristics. Seven models have been robustly externally validated, and implementation data have been published for two of these models. All models demonstrated better performance than the healthcare-associated pneumonia criteria, with most favoring sensitivity over specificity. We also report validation of the novel, risk factor-based treatment algorithm proposed in the American Thoracic Society/Infectious Diseases Society of America guidelines which strongly favors specificity over sensitivity, especially in nonsevere pneumonia.

SUMMARY

Using patient-level risk factors to guide the decision whether to prescribe broad-spectrum antibiotics is a rational approach to treatment. Several viable candidate prediction models are available. Hospitals should evaluate the local performance of existing scores before implementing in routine clinical practice.

Culture-negative sepsis

PURPOSE OF REVIEW

The traditional approach to sepsis treatment utilizes broad-spectrum antibiotics. Unfortunately, a significant proportion of infected patients have 'culture-negative' sepsis despite appropriate microbiologic assessment.

RECENT FINDINGS

There has been increased interest in the past decade on the treatment of culture-negative sepsis. Outcome data comparing culture-negative sepsis with culture-positive sepsis are mixed and it is unclear if culture-negative sepsis is a distinct entity. Recent recommendations promoting antibiotic de-escalation in culture-negative sepsis can be difficult to implement. A variety of strategies have been suggested for limiting antibiotic courses among patients with negative cultures, including limiting antibiotic durations, use of antibiotic stewardship programs, early consideration of narrow antibiotics, rapid diagnostic technology, and eliminating anti-MRSA therapy based on surveillance swabs.

SUMMARY

Owing to the difficulty inherent in studying the lack of positive data, and to the uncertainty surrounding diagnosis in patients with culture-negative sepsis, prospective data to guide antibiotic choices are lacking. However, antibiotic de-escalation in culture-negative sepsis is both recommended and feasible in patients showing clinical signs of improvement. Increased use of rapid diagnostics, careful consideration of antibiotic necessity, and antibiotic stewardship programs may result in less antibiotic days and better outcomes.

Vancomycin plus piperacillin/tazobactam and acute kidney injury risk: A review of the literature

WHAT IS KNOWN AND OBJECTIVE

Acute kidney injury is a devastating consequence observed with antibiotic therapy. The objective of this review was to summarize available data regarding the rates of acute kidney injury with vancomycin plus piperacillin/tazobactam compared to other beta-lactam combinations.

METHODS

A PubMed search from 2011 to May 2020 was conducted using the following search terms: vancomycin AND piperacillin/tazobactam AND acute kidney injury. Additional references were identified from a review of citations. Articles evaluating exclusively paediatric patients and articles evaluating vancomycin monotherapy as the comparator group were excluded. Case reports and case series were also excluded.

RESULTS AND DISCUSSION

There were 18 studies included. Ten studies adjusted for potential confounders of acute kidney injury. Fourteen retrospective studies, one prospective study and three meta-analyses found the combination of vancomycin/piperacillin/tazobactam to be associated with a higher rate of acute kidney injury than the comparator group(s).

WHAT IS NEW AND CONCLUSION

Although there are data to support that the combination of vancomycin plus piperacillin-tazobactam increases the risk of acute kidney, much of the data come from small retrospective studies with variable adjustment for confounders. Furthermore, study heterogeneity on inclusion criteria and evaluation of long-term outcomes should be cautiously interpreted. Finally, additional data suggest that the risk of acute kidney injury seems to be minimized with shorter courses of therapy. Without prospective studies available, antimicrobial stewardship efforts should continue to target reducing broad-spectrum regimens, often limiting the need for long-term vancomycin/piperacillin/tazobactam combination.

Antimicrobial De-Escalation in the ICU: From Recommendations to Level of Evidence

Antimicrobial de-escalation (ADE) is a component of antimicrobial stewardship (AMS) aimed to reduce exposure to broad-spectrum antimicrobials. In the intensive care unit, ADE is a strong recommendation that is moderately applied in clinical practice. Following a systematic review of the literature, we assessed the studies identified on the topic which included one randomized controlled trial and 20 observational studies. The literature shows a low level of evidence, although observational studies suggested that this procedure is safe. The effects of ADE on the level of resistance of ecological systems and especially on the microbiota are unclear. The reviewers recommend de-escalating antimicrobial treatment in patients requiring long-term antibiotic therapy and considering de-escalation in short-term treatments.

Impact of Nasal Swabs on Empiric Treatment of Respiratory Tract Infections (INSERT-RTI)

Methicillin-resistant Staphylococcusaureus (MRSA) polymerase-chain-reaction nasal swabs (PCRNS) are a rapid diagnostic tool with a high negative predictive value. A PCRNS plus education “bundle” was implemented to inform clinicians on the utility of PCRNS for anti-MRSA therapy de-escalation in respiratory tract infections (RTI). The study included patients started on vancomycin with a PCRNS order three months before and after bundle implementation. The primary objective was the difference in duration of anti-MRSA therapy (DOT) for RTI. Secondary objectives included hospital length of stay (LOS), anti-MRSA therapy reinitiation, 30-day readmission, in-hospital mortality, and cost. We analyzed 62 of 110 patients screened, 20 in the preintervention and 42 in the postintervention arms. Mean DOT decreased after bundle implementation by 30.3 h (p = 0.039); mean DOT for patients with a negative PCRNS decreased by 39.7 h (p = 0.014). Median cost was lower after intervention [USD$51.69 versus USD$75.30 (p < 0.01)]. No significant difference in LOS, mortality, or readmission existed. The bundle implementation decreased vancomycin therapy and cost without negatively impacting patient outcomes.

Discontinuation of Glycopeptides in Patients with Culture Negative Severe Sepsis or Septic Shock: A Propensity-Matched Retrospective Cohort Study

Implementation of antibiotic stewardship is difficult in patients with sepsis because of severity of disease. We evaluated the impact of glycopeptide discontinuation (GD) in patients with culture negative severe sepsis or septic shock who received glycopeptides as initial empiric antibiotic therapy at admission. We conducted a single center retrospective cohort study between January 2010 and March 2018. GD was defined as discontinuation of initial empiric glycopeptides on availability of culture results, revealing the absence of identified pathogens. In 92 included patients, the leading causes of sepsis were pneumonia (34.8%) and intra-abdominal infection (23.9%); 28-day mortality and overall mortality were 14% and 21%, respectively. Glycopeptides were discontinued in 42/92 patients. After propensity score matching, baseline characteristics were not significantly different between the GD and non-GD (GND) groups. GND was associated with development of acute kidney injury (OR 5.54, 95% CI 1.49–20.6, P = 0.011). GD did not increase the 7-day, 14-day, and 28-day mortality compared with GND. The length of hospital stay was shorter in the GD group than in GND group (16.33 ± 17.11 vs. 25.05 ± 14.37, P = 0.082), though not statistically significant. GD may be safe and reduce adverse events of prolonged antibiotic use in patients with culture negative severe sepsis or septic shock receiving glycopeptides as initial empiric antibiotic therapy.

Inapropriate use of antibiotics effective against gram positive microorganisms despite restrictive antibiotic policies in ICUs: a prospective observational study

Background

Gram-positive spectrum antibiotics such as vancomycin, teicoplanin, daptomycin, and linezolid are frequently used in empirical treatment combinations in critically ill patients. Such inappropriate and unnecessary widespread use, leads to sub-optimal utilisation. However they are covered by the antibiotics restriction programme. This prospective observational study, evaluates gram-positive anti-bacterial utilisations in intensive care units (ICUs) with various evaluation criteria, to determine the frequency of inappropriate usage and the intervention targets required to ensure optimum use.

Methods

This clinical study was conducted prospectively between 01.10.2018 and 01.10.2019 in the medical and surgical ICUs of Gazi University Faculty of Medicine Hospital, Turkey. The total bed capacity was 55. Patients older than 18 years and who were prescribed gram-positive spectrum antibiotics (vancomycin, teicoplanin, linezolid, and daptomycin) were included. Patients under this age or immunosuppressed patients (neutropenic,- HIV-infected patients with hematologic or solid organ malignancies) were not included in the study. During the study period, 200 treatments were evaluated in 169 patients. The demographic and clinical features of the patients were recorded. Besides observations by the clinical staff, the treatments were recorded and evaluated by two infectious diseases specialists and two clinical pharmacists at 24-h intervals from the first day to the last day of treatment.

SPSS software for Windows, (version 17, IBM, Armonk, NY) was used to analyse the data. Categorical variables were presented as number and percentage, and non-categorical variables were presented as mean ± standard deviation.

Results

It was found that inappropriate gram-positive antibiotic use in ICUs was as high as 83% in terms of non-compliance with the selected quality parameters. Multivariate analysis was performed to evaluate the factors associated with inappropriate antibiotic use, increased creatinine levels were found to increase the risk of such use.

Conclusions

In spite of the restricted antibiotics programme, inappropriate antibiotic use in ICUs is quite common. Thus, it is necessary to establish local guidelines in collaboration with different disciplines for the determination and follow-up of de-escalation of such use and optimal treatment doses.

Impact of antimicrobial de-escalation on mortality: a literature review of study methodology and recommendations for observational studies

Introduction: The safety of de-escalation of empirical antimicrobial therapy is largely based on observational data, with many reporting protective effects on mortality. As there is no plausible biological explanation for this phenomenon, it is most probably caused by confounding by indication.Areas covered: We evaluate the methodology used in observational studies on the effects of de-escalation of antimicrobial therapy on mortality. We extended the search for a recent systematic review and identified 52 observational studies. The heterogeneity in study populations was large. Only 19 (36.5%) studies adjusted for confounders and four (8%) adjusted for clinical stability during admission, all as a fixed variable. All studies had methodological limitations, most importantly the lack of adjustment for clinical stability, causing bias toward a protective effect.Expert opinion: The methodology used in studies evaluating the effects of de-escalation on mortality requires improvement. We depicted all potential confounders in a directed acyclic graph to illustrate all associations between exposure (de-escalation) and outcome (mortality). Clinical stability is an important confounder in this association and should be modeled as a time-varying variable. We recommend to include de-escalation as time-varying exposure and use inverse-probability-of-treatment weighted marginal structural models to properly adjust for time-varying confounders.

Antimicrobial de-escalation in critically ill patients: a position statement from a task force of the European Society of Intensive Care Medicine (ESICM) and European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Critically Ill Patients Study Group (ESGCIP)

BACKGROUND

Antimicrobial de-escalation (ADE) is a strategy of antimicrobial stewardship, aiming at preventing the emergence of antimicrobial resistance (AMR) by decreasing the exposure to broad-spectrum antimicrobials. There is no high-quality research on ADE and its effects on AMR. Its definition varies and there is little evidence-based guidance for clinicians to use ADE in the intensive care unit (ICU).

METHODS

A task force of 16 international experts was formed in November 2016 to provide with guidelines for clinical practice to develop questions targeted at defining ADE, its effects on the ICU population and to provide clinical guidance. Groups of 2 experts were assigned 1-2 questions each within their field of expertise to provide draft statements and rationale. A Delphi method, with 3 rounds and an agreement threshold of 70% was required to reach consensus.

RESULTS

We present a comprehensive document with 13 statements, reviewing the evidence on the definition of ADE, its effects in the ICU population and providing guidance for clinicians in subsets of clinical scenarios where ADE may be considered.

CONCLUSION

ADE remains a topic of controversy due to the complexity of clinical scenarios where it may be applied and the absence of evidence to the effects it may have on antimicrobial resistance.

Hospital Medicine Update: High-Impact Literature from March 2018 to April 2019

To assist busy hospital medicine clinicians, we summarized 10 impactful articles from last year. The authors reviewed articles published between March 2018-April 2019 for the Hospital Medicine Updates at the Society of Hospital Medicine and the Society of General Internal Medicine Annual Meetings. The authors voted to select 10 of 30 presented articles based on quality and clinical impact for this summary. The key findings include: (1) Vancomycin or fidaxomicin are the first-line treatment for initial Clostridioides difficile infection; (2) Unnecessary supplemental oxygen is linked to increased mortality; aim for a target oxygen saturation of 90%-94% in most hospitalized patients; (3) Stigmatizing language in medical records impacts physician trainees' attitudes and pain management practices; (4) Consider ablation for atrial fibrillation in patients with heart failure; (5) Patients with opioid use disorder should be offered buprenorphine or methadone therapy; (6) Apixaban is safe and may be preferable over warfarin in patients with atrial fibrillation and end-stage kidney disease; (7) It is probably safe to discontinue antimethicillin-resistant Staphylococcus aureus (MRSA) coverage in patients with hospital-acquired pneumonia who are improving and have negative cultures; (8) Selected patients with left-sided endocarditis (excluding MRSA) may switch from intravenous (IV) to oral antibiotics if they are clinically stable after 10 days; (9) Oral antibiotics may be equivalent to IV antibiotics in patients with joint and soft tissue infections; (10) A history-electrocardiogram-age-risk factors-troponin (HEART) score ≥4 is a reliable threshold for determining the patients who are at risk for short-term major adverse cardiac events and may warrant further evaluation.

Time to First Culture Positivity Among Critically Ill Adults With Methicillin-Resistant Staphylococcus aureus Growth in Respiratory or Blood Cultures

Background: For critically ill adults receiving empirical vancomycin, the duration of negative cultures after which vancomycin may be discontinued without risking subsequent growth of methicillin-resistant Staphylococcus aureus (MRSA) remains unknown. Objective: We hypothesized that if sputum cultures did not grow MRSA or blood cultures did not grow Gram-positive cocci on Gram stain by 48 hours, those cultures would not subsequently demonstrate MRSA. Methods: We conducted an ancillary analysis from patients enrolled in the Isotonic Solutions and Major Adverse Renal Events Trial (SMART). In this cohort of patients, we collected data on the time of either MRSA identification in culture or Gram-positive cocci identification on Gram stain and rate of vancomycin discontinuation. Results: Of the 15 802 patient admissions in the SMART study, 6553 (41.5%) received empirical intravenous vancomycin. Respiratory sputum cultures demonstrated MRSA during 178 patient admissions. Among respiratory cultures that would ultimately grow MRSA, 85% were positive within 48 hours, and 97% were positive within 72 hours. Cultures demonstrated MRSA bacteremia during 85 patient admissions. In 83 cases (97.6%) of MRSA bacteremia, Gram-positive cocci were identified within 48 hours after the culture was obtained. Conclusion and Relevance: This analysis of a large cohort of critically ill adults receiving empirical vancomycin found that Staphylococcus aureus was present in all but 15% of cases of MRSA-positive respiratory cultures after 48 hours, whereas Gram-positive cocci were identified within 48 hours during nearly all episodes of MRSA bacteremia. These findings may inform the timing of discontinuation of empirical vancomycin among critically ill adults.

Safety of antimicrobial de-escalation for culture-negative severe pneumonia

Purpose

This study investigated the outcomes of antimicrobial de-escalation (ADE) based on mortality and the incidence of multi-drug resistant (MDR) pathogen occurrence in patients with culture-negative pneumonia presenting with sepsis and septic shock.

Materials and Methods

We retrospectively analyzed patients diagnosed with severe pneumonia requiring intensive care unit (ICU) admission and possessing negative microbiological culture results at a tertiary referral hospital in South Korea from March 2008 to July 2018.

Results

We identified 107 patients with culture-negative pneumonia. The Acute Physiologic and Chronic Health Evaluation (APACHE) II and Sepsis-related Organ Failure Assessment (SOFA) mean scores were 20.3 ± 8.6 and 9.6 ± 3.3, respectively. Among the patients, 40 (37.4%) underwent ADE. The APACHE II, SOFA, and follow-up SOFA scores did not differ significantly between the groups, and no differences were found in ICU mortality and MDR pathogen occurrence (27.5% vs 41.8%, P = .137 and 15.0% vs 16.9% P = .794, respectively).

Conclusions

We observed similar ICU mortality and MDR pathogen occurrence in patients with culture-negative pneumonia presenting with sepsis/shock regardless of whether they received ADE. Additionally, ADE lowered the antimicrobial burden.

•

MDR pathogen occurrence was not reduced in patients who underwent ADE.

•

ADE was not significantly associated with increased ICU mortality.

•

Antimicrobial burden was significantly lower in ADE group.

Utilizing the Patient Care Process to Minimize the Risk of Vancomycin-Associated Nephrotoxicity

Vancomycin-associated acute kidney injury (AKI) is a popular topic in the medical literature with few clear answers. While many studies evaluate the risk of AKI associated with vancomycin, few data are high quality and/or long in duration of follow-up. This review takes the clinician through an approach to evaluate a patient for risk of AKI. This evaluation should include patient assessment, antibiotic prescription, duration, and monitoring. Patient assessment involves evaluating severity of illness, baseline renal function, hypotension/vasopressor use, and concomitant nephrotoxins. Evaluation of antibiotic prescription includes evaluating the need for methicillin-resistant Staphylococcus aureus (MRSA) coverage and/or vancomycin use. Duration of therapy has been shown to increase the risk of AKI. Efforts to de-escalate vancomycin from the antimicrobial regimen, including MRSA nasal swabs and rapid diagnostics, should be used to lessen the likelihood of AKI. Adequate monitoring includes therapeutic drug monitoring, ongoing fluid status evaluations, and a continual reassessment of AKI risk. The issues with serum creatinine make the timely evaluation of renal function and diagnosis of the cause of AKI problematic. Most notably, concomitant piperacillin-tazobactam can increase serum creatinine via tubular secretion, resulting in higher rates of AKI being reported. The few studies evaluating the long-term prognosis of AKI in patients receiving vancomycin have found that few patients require renal replacement therapy and that the long-term risk of death is unaffected for patients surviving after the initial 28-day period.