Economic justification of antimicrobial management programs: implications of antimicrobial resistance

Incidence, risk factors, and outcome of blood stream infections during the first 100 days post-pediatric allogeneic and autologous hematopoietic stem cell transplantations

Bloodstream infections (BSI) are a frequently observed complication after hematopoietic stem cell transplant (HSCT). Retrospective analysis of clinical and microbiological data during the first 100 days from 302 consecutive pediatric patients who underwent HSCT for a malignant disease at our institute between January 2013 and June 2017. A total of 164 patients underwent autologous and 138 allogeneic HSCT. The overall incidence of BSI was 37% with 92% of infectious episodes occurring during the pre-engraftment phase. Gram-positive bacteria (GPB) accounted for 54.6% of the isolated pathogens, gram-negative bacteria (GNB) for 43.9%, and fungi for 1.4%. Coagulase-negative staphylococci and Escherichia coli were the most commonly isolated GPB and GNB, respectively. Forty-five percent of GNB were extended-spectrum beta-lactamase producers and 21% were multidrug-resistant organisms. Fluoroquinolone resistance was 92% and 68%, among GPB and GNB, respectively. Risk factors for BSI in univariate analysis were allogeneic HSCT, delayed time to engraftment more than 12 days, previous BSI before HSCT, and alternative donor. In multivariate analysis, only HSCT type (allogeneic vs autologous P = .03) and previous BSI within 6 months before HSCT (P = .016) were significant. Overall survival at day 100 was 98% and did not differ significantly between patients with and without BSI (P = .76). BSI is common in children undergoing HSCT for malignant diseases. Allogeneic HSCT recipients and previous BSI within 6 months before HSCT are associated with increased risk of post-transplant BSI. With current supportive measures, BSI does not seem to confer an increased risk for 100-day mortality.

Antibiotic-Stewardship Practices at Top Academic Centers Throughout the United States and at Hospitals Throughout Massachusetts

Objective.

Improvements in antibiotic prescribing to reduce bacterial resistance and control hospital costs is a growing priority, but the way to accomplish this is poorly defined. Our goal was to determine whether certain antibiotic stewardship interventions were universally instituted and accepted at top US academic centers and to document what interventions, if any, are used at both teaching and community hospitals within a geographic area.

Design.

Two surveys were conducted. In survey 1, detailed phone interviews were performed with the directors of antibiotic stewardship programs at 22 academic medical centers that are considered among the best for overall medical care in the United States or as leaders in antibiotic stewardship programs. In survey 2, teaching and community hospitals throughout Massachusetts were surveyed to ascertain what antibiotic oversight program components were present.

Results.

In survey 1, each of the 22 participating hospitals had instituted interventions to improve antibiotic prescribing, but none of the interventions were universally accepted as essential or effective. In survey 2, of 97 surveys that were mailed to prospective participants, a total of 54 surveys from 19 teaching hospitals and 35 community hospitals were returned. Ninety-five percent of the teaching hospitals had a restricted formulary, compared with 49% of the community hospitals, and 89% of teaching hospitals had an antibiotic approval process, compared with 29% of community hospitals.

Conclusion.

There was great variability among the approaches to the oversight of antibiotic prescribing at major academic hospitals. Antibiotic management interventions were lacking in more than half of the Massachusetts community hospitals surveyed. More research is needed to define the best antibiotic stewardship interventions for different hospital settings.

Blood stream infections in allogeneic hematopoietic stem cell transplant recipients: reemergence of Gram-negative rods and increasing antibiotic resistance

Blood stream infections (BSI) are a well-known cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) patients. The aim of this study was to analyze etiology and microbial resistance of BSI in patients undergoing allogeneic HSCT in a single center over a 4-year period (2004-2007). There were 168 episodes of BSI in 132 patients (median 10 days after HSCT) and 182 pathogens were isolated. Gram-positive bacteria (GPB) accounted for 57% of 182 isolates. Gram-negative rods (GNR) for 37% and fungi for 6%. All patients received routine fluoroquinolone prophylaxis. There was a significant decrease in GPB/GNR ratio over time, from 2.4 in 2004 to 1 in 2007 (P = .043). Among GPB, staphylococci decreased from 37 of 68 (64%) in 2004-2005 to 8 of 35 (23%) in 2006-2007 (P < .002). The Enterococcus faecalis/E. faecium ratio decreased from 4.5 in 2004 to 0.33 in 2007 (P = .006), whereas the total number of enterococcal strains per year did not change. The incidence of Escherichia coli among GNR increased from 3 of 15 (20%) in 2004 to 13 of 21 (62%) in 2007 (P = .003). Fluoroquinolone-resistance was common, both among GPB and GNR (81% and 74%, respectively). Mortality rate at 7 days after BSI was 11% (19 of 168), reaching 39% for Pseudomonas aeruginosa BSI (7 of 18). BSI remains a frequent and potentially life-threatening complication of allogeneic HSCT, the causative organism influencing 7- and 30-day mortality rate. BSI etiology may change rapidly, requiring implementation of new empirical-therapy schemes.

Antimicrobial stewardship in institutions and office practices

Medically inappropriate, ineffective and economically inefficient use of antimicrobials is commonly observed in the health care units throughout the world especially in the developing countries. Antimicrobial stewardship programs attempt to balance the demand for these life-saving drugs with the need to preserve their future efficacy. A comprehensive evidence-based stewardship program should include elements chosen from the recommendations based on local antimicrobials use and resistance problems and on available resources that may differ, depending on the size of the institution or clinical setting. For success of antibiotic stewardship it is essential to increase awareness amongst medical professionals. Discipline in antimicrobial prescribing is most vital in clinical settings. A careful assessment of the benefits of prescribing against the risk of non-prescribing of antibiotics should be considered. It should be an endeavor of every physician to justify antibiotic prescription in case of empirical use. Integration of advanced information technology into antimicrobial stewardship programs holds the potential to both reduce antimicrobial overuse and improve outcomes.

Epidemiology of bacteremia and factors associated with multi-drug-resistant gram-negative bacteremia in hematopoietic stem cell transplant recipients

The incidence of Gram-negative bacteremia has increased in hematopoietic stem cell transplant (HSCT) recipients. We prospectively collected data from 13 Brazilian HSCT centers to characterize the epidemiology of bacteremia occurring early post transplant, and to identify factors associated with infection due to multi-drug-resistant (MDR) Gram-negative isolates. MDR was defined as an isolate with resistance to at least two of the following: third- or fourth-generation cephalosporins, carbapenems or piperacillin-tazobactam. Among 411 HSCT, fever occurred in 333, and 91 developed bacteremia (118 isolates): 47% owing to Gram-positive, 37% owing to Gram-negative, and 16% caused by Gram-positive and Gram-negative bacteria. Pseudomonas aeruginosa (22%), Klebsiella pneumoniae (19%) and Escherichia coli (17%) accounted for the majority of Gram-negative isolates, and 37% were MDR. These isolates were recovered from 20 patients, representing 5% of all 411 HSCT and 22% of the episodes with bacteremia. By multivariate analysis, treatment with third-generation cephalosporins (odds ratio (OR) 10.65, 95% confidence interval (CI) 3.75-30.27) and being at one of the hospitals (OR 9.47, 95% CI 2.60-34.40) were associated with infection due to MDR Gram-negative isolates. These findings may have important clinical implications in the decision of giving prophylaxis and selecting the empiric antibiotic regimen.

Beta-lactam resistance in the gram negatives: increasing complexity of conditional, composite and multiply resistant phenotypes

The greatest impact of microbiology data on clinical care is in the critically ill. Unfortunately, this is also the area in which microbiology laboratories are most often non-contributive. Attempts to move to rapid, culture-independent diagnostics are driven by the need to expedite urgent results. This is difficult in Gram-negative infection because of the complexity of the antibiotic resistance phenotype. Here, we discuss resistance to modern beta-lactams as a case in point. Recent outbreaks of transmissible carbapenem resistance among Gram-negative enteric pathogens in Sydney and Melbourne serve to illustrate the pitfalls of traditional phenotypical approaches. A better understanding of the epidemiology and mosaic nature of antibiotic resistance elements in the microflora is needed for us to move forward.

Impact of antibiotic restrictions: the ethical perspective

Antibiotic restrictions present difficult choices for physicians, patients and payors. Physicians must choose between the welfare of the patient and the directive of healthcare systems to restrict antibiotics. These may be supported with incentives or penalties, causing a conflict of interest. The patient has an expectation of best care, but will often be unaware of antibiotic restriction policies and is therefore not fully informed about his/her treatment. For payors, reducing the volume of antibiotic prescribing and/or prescribing less expensive antibiotics are apparently attractive targets for cost savings. However, we are only now beginning to understand the downstream consequences of restricting antibiotics on outcomes and costs. We are hampered by the lack of a universal ethical framework and information on outcomes. In addition, the concept of 'effective' or 'best' therapy will vary among different groups. Balancing the risks of treating or not treating with antibiotics is complex. Suboptimal therapy, that fails to eradicate the bacterial infection, exposes the patient to the risk of poor outcome, adverse events and the wider risk of antimicrobial resistance. Failure to treat where the risk of a poor outcome exceeds the risk of an adverse event is also ethically unacceptable. The key to rational antibiotic prescribing is to identify those patients who need antibiotic therapy and optimise therapy to achieve the fastest bacterial and clinical cure. We are only now beginning to assemble the information and tools to be able to make such decisions. Above all, we should treat on the basis of knowledge.

Antimicrobial Management of Complicated Skin and Skin Structure Infections in the Era of Emerging Resistance

BACKGROUND

Complicated skin and skin structure infections (cSSSIs) are among the most common infections treated in the hospital setting. The mainstays of treatment continue to be antimicrobial therapy combined with appropriate surgical intervention. Due to increasing resistance among pathogens commonly implicated in cSSSIs, the objectives of this review were to describe the potential pathogens causing skin infections, the implications of resistance to currently used drug therapy, and the role of new antibiotics with activity for pathogens causing cSSSIs.

METHODS

Relevant information from the primary literature and review articles were identified through a MEDLINE search of the medical literature (1980 to the present) using the terms abscess, wound infection, skin and skin structure infection, antibiotics, resistance, quinupristin- dalfopristin, linezolid, daptomycin, tigecycline, oritavancin, and dalbavancin. Meeting posters and slides were identified from the Interscience Conference of Antimicrobial Agents and Chemotherapy (1998-2004) for supplemental data.

RESULTS

The most commonly implicated pathogens in cSSSIs include gram-positive bacteria, specifically Staphylococcus aureus. Gram-negative and mixed organisms are additionally encountered in serious cSSSI. Antimicrobial resistance among both gram-positive and gramnegative bacteria has increased significantly during the last decade, with methicillin resistance among S. aureus approaching 60% in hospitals and becoming more frequent in the community as well. As a result, resistance is the driving factor for treatment failure and rising costs for infection management. Few antimicrobial agents are available currently to treat resistant bacteria in cSSSIs; vancomycin is currently the drug of choice against resistant grampositive cocci; however, resistance to this agent has appeared in enterococci and S. aureus. Several new antibiotics such as linezolid and daptomycin are now available for the management of cSSSIs. Other agents such as tigecycline are under investigation and should be available soon to increase treatment options for cSSSIs caused by resistant bacteria.

CONCLUSIONS

Although the resistance of cSSSI pathogens is problematic, new antibiotics with broad-spectrum activity against resistant gram-positive and gram-negative bacteria are promising for the management of severe cSSSIs.

The Development of an Antimicrobial Stewardship Program at a Pediatric Hospital

This continuing feature will focus on recent advancements in the areas of pediatrics and neonatal pharmacology and on methods for reducing medication error risk in this patient population. Most pharmacological agents are designed with the adult in mind, and there is little literature-based data from which to derive dosing schedules and proper drug administration techniques for the pediatric and neonatal patient. Moreover, pharmacological response in this group is not well understood. We hope that this feature will help you provide pharmaceutical care to this high-risk population. Direct questions or comments to hospitalpharmacy@drugfacts.com .

Surveillance of antimicrobial use and antimicrobial resistance in intensive care units (SARI): 1. Antimicrobial use in German intensive care units

OBJECTIVE

To study antimicrobial use for benchmarking and ensuring quality of antimicrobial treatment and to identify risk factors associated with the high use of antimicrobials in German intensive care units (ICUs) through implementation of the SARI (Surveillance of Antimicrobial Use and Antimicrobial Resistance in ICUs) system.

DESIGN

Prospective, unit-based surveillance on antimicrobial use from February, 2000, until June, 2002. The data are standardised by use of the defined daily dose (DDD) for each antimicrobial defined by the WHO and by calculating use per 1000 patient days.

SETTING

The data were obtained from 35 German ICUs and stratified by type of ICU (medical, surgical, interdisciplinary).

RESULTS

To date, the project covers a total of 266,013 patient days in 744 reported ICU months and 354,356 DDDs. Mean antimicrobial use density (AD) was 1,332 DDD/1000 patient days and was correlated with length of stay. Penicillins with beta-lactamase inhibitor (AD 338.3) and quinolones (155.5) were the antimicrobial group with the highest ADs. Comparison with US ICARE (Intensive Care Antimicrobial Resistance Epidemiology)/AUR (Antimicrobial Use and Resistance) data revealed a higher AD for glycopeptides and 3rd generation cephalosporins in ICARE/AUR ICUs, but a higher AD for carbapenems in German SARI ICUs regardless of the type of ICU. In the multivariate analysis, length of stay was an independent risk factor for an AD above the 75% percentile of the total amount of antimicrobials used (OR 1.96 per day); likewise, for the AD above the 75% percentile of carbapenems (OR 1.90 per day) and penicillins with extended spectrum (OR 2.01 per day). High use of glycopeptides and quinolones (AD >75% percentile) correlated with central venous catheter (CVC) rate (OR 1.14 per CVC day per 100 patient days and 1.16, respectively).

CONCLUSION

The SARI data on antimicrobials serve ICUs as a benchmark by which to improve the quality of antimicrobial drug administration and for international comparison.

Moving from recommendation to implementation and audit: part 1. Current recommendations and programs: a critical commentary

Growing concern over the spread of resistance to antibiotics and other antimicrobials has prompted a plethora of recommendations for its control. Strategic programs for resistance containment have been initiated in various countries, particularly in Western Europe and North America. The World Health Organization and the European Union have responded to the need for international action by publishing guidance and encouraging collaboration. These recommendations rightly focus on controlling resistance in the community. They agree on the importance of surveillance of resistance patterns and antibiotic usage and the need to encourage judicious antibiotic usage (especially through education of prescribers and the public). Yet there remains a pressing need for the implementation of effective actions to address these issues. Important considerations given less attention include infection prevention (e.g. through immunization), the use of rapid diagnostic tests to reduce antibiotic usage, audit of implemented actions, and the provision of feedback. Furthermore, research is necessary to fill the substantial gaps in our knowledge. Notably, the reversibility or containment of resistance with the optimization of antibiotic usage has yet to be definitely established. For now, antimicrobial management programs should focus on ensuring the most appropriate use of antimicrobials rather than simply on limiting choices. Finally, developed countries must recognize that a truly global approach to resistance containment will require greater support for developing countries.

Clinical experience of quinupristin-dalfopristin for the treatment of antimicrobial-resistant gram-positive infections

Data regarding clinical administration, outcomes, and costs of quinupristin-dalfopristin treatment in 48 patients with serious gram-positive infections in a large teaching hospital were analyzed retrospectively. Thirty-six patients had vancomycin-resistant Enterococcus faecium (VREF) infections, 10 had methicillin-resistant Staphylococcus aureus (MRSA) or Staphylococcus epidermidis (MRSE) infections, and 2 were treated empirically Overall, 67% of the patients were clinically cured, and 56% had bacteriologic eradication; overall response rate was 48%. Patients with VREF bacteremia had the highest clinical cure (82%) and bacteriologic eradication (73%) rates. Mortality rate was 31%, but 6 of 15 patients who died were treated successfully with quinupristin-dalfopristin. Length of hospital stay was significantly shorter among patients who lived versus those who died (p<0.05). Similarly, the mean hospital cost/patient was significantly lower in patients who lived than in those who died ($35,244 vs $122,922). Quinupristin-dalfopristin is effective in the treatment of both VREF and MRSA or MRSE infections in patients who fail to respond to, or are intolerant of, vancomycin.

Clinafloxacin versus piperacillin/tazobactam in the treatment of severe skin and soft-tissue infections in adults at a Veterans Affairs medical center

BACKGROUND

Severe skin and soft-tissue infections (SSTIs), particularly diabetic foot infections, are a source of considerable morbidity and mortality. Inappropriate antimicrobial therapy may contribute to the increasing emergence of bacterial resistance, as well as to increased health care costs. Thus, there is a continuing search for reasonably safe, well-tolerated, and effective antimicrobial agents that are less susceptible to the development of resistance than older agents.

OBJECTIVE

The Department of Veterans Affairs (VA) Medical Center in Nashville, Tennessee, was I site in a multicenter, Phase III, randomized, investigator-blinded clinical trial comparing the safety and efficacy of clinafloxacin with those of piperacillin/tazobactam in the treatment of adult patients with SSTI.

METHODS

Over an 18-month period, patients aged > or = 18 years with physical findings of acute bacterial SSTI requiring hospitalization and intravenous antimicrobial therapy were randomized in a 1:1 ratio to receive either clinafloxacin 200 mg IV every 12 hours or piperacillin/tazobactam 3.375 g IV every 6 hours. After a minimum of 3 days of intravenous therapy, a switch to oral therapy with clinafloxacin 200 mg PO every 12 hours or amoxicillin/clavulanate 500 mg PO every 8 hours could be made in the respective treatment groups.

RESULTS

The center enrolled 84 patients (42 in each group), all but I of whom were male, reflecting the typical VA medical center population. The mean age was 60 years (range, 36-80 years) in the clinafloxacin group and 65 years (range, 35-87) in the piperacillin/tazobactam group; the latter group was significantly older (P = 0.0482), which could have affected recovery rates. Sixty-six patients were white and 18 were black. The mean ( +/- SD) duration of treatment was 10.69 +/- 5.34 days in the clinafloxacin group and 12.07 +/- 5.06 days in the piperacillin/tazobactam group; the mean length of stay was 10.83 +/- 10.28 days and 14.95 +/- 19.20 days, respectively. Fifty-three (63%) patients were switched to oral therapy (21 in the clinafloxacin group, 32 in the piperacillin/tazobactam group). The most commonly isolated pathogens were Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Enterobacter cloacae. Clinical cure rates and microbiologic eradication rates were similar between the 2 treatments. The piperacillin/ tazobactam arm experienced more all-cause adverse events than the clinafloxacin arm, although the difference was not statistically significant. The clinafloxacin arm experienced significantly more adverse events (eg, photosensitivity) that were judged by the investigator to be drug related (P = 0.034).

CONCLUSIONS

In this study population of hospitalized adults, clinafloxacin was as effective as piperacillin/tazobactam in the treatment of complicated SSTIs. Appropriate precautions must be taken against exposure to sunlight and ultraviolet light in patients receiving clinafloxacin, and adequate monitoring is necessary. Further investigation is necessary into how the phototoxic effects of the flu oroquinolones can be limited.

Antimicrobial management strategies for Gram-positive bacterial resistance in the intensive care unit

This article summarizes the current situation with Gram-positive infections, including the two primary consequences-failure to cure and resistance-relevant to the intensive care unit. The past few years have seen Enterococcus faecium resistance to vancomycin increase from 10% of strains to approaching 60% of strains in some centers. Failure is now so frequent that vancomycin can no longer be safely used. This has lead to use of two new antibiotics, quinupristin/dalfopristin (Synercid), first marketed in the United States in September 1999, and linezolid (Zyvox), which reached the U.S. market in May 2000. Both of these agents are being used to treat culture-proven vancomycin-resistant E. faecium. The calculated areas under the inhibitory curve (AUIC) values of vancomycin, even when its minimal inhibitory concentration (MIC) is 4.0 microg/mL, show almost all vancomycin-resistant E. faecium have AUICs <125. This explains failure, as well as the further selection of this bacteria into subpopulations with progressively higher MICs. Less well defined, but potentially an even greater problem, is the poor efficacy of vancomycin against multiresistant Staphylococcus aureus. Here, there is evidence of clinical failure in lower respiratory tract infection patients, but in most cases the MIC values of the organism have not risen to the point where AUICs are <125. However, the minimum bactericidal concentration of this organism may be considerably higher than its MIC, and in other cases there may be a high inoculum effect or a protein-binding effect to explain the failure of vancomycin to kill multiresistant S. aureus. Besides the increasing use of the new agents, strategies to manage these two increasingly resistant Gram-positive infections include cephalosporin restriction, switch and streamlining when cultures come back from the lab, combination regimens, and cycling in selected intensive care units.