US outpatient antibiotic prescribing variation according to geography, patient population, and provider specialty in 2011

Antibiotic-Induced Gut Microbiota Disruption Decreases TNF-α Release by Mononuclear Cells in Healthy Adults

Objectives:

Broad-spectrum antibiotics disrupt the intestinal microbiota. The microbiota is essential for physiological processes, such as the development of the gut immune system. Recent murine data suggest that the intestinal microbiota also modulates systemic innate immune responses; however, evidence in humans is lacking.

Methods:

Twelve healthy young men were given oral broad-spectrum antibiotics (ciprofloxacin 500 mg bid, vancomycin 500 mg tid and metronidazole 500 mg tid) for 7 days. At baseline, 1 day, and 6 weeks after antibiotics, blood and feces were sampled. Whole blood and isolated mononuclear cells were stimulated with selected Toll-like receptor agonists and heat-killed bacteria. Microbiota diversity and composition was determined using bacterial 16S rDNA sequencing.

Results:

One day after the antibiotic course, microbial diversity was significantly lower compared with baseline. After antibiotic therapy, systemic mononuclear cells produced lower levels of tumor necrosis factor (TNF)-α after ex vivo stimulation with lipopolysaccharide (LPS). This diminished capacity to produce TNF-α was restored 6 weeks after cessation of antibiotic therapy. In whole blood, a reduced capacity to release interleukin (IL)-1β and IL-6 was observed after LPS stimulation. Antibiotic treatment did not impact on differential leukocyte counts, phagocytosis, and cell surface markers of neutrophils and monocytes.

Conclusions:

In this proof-of-principle study of healthy subjects, microbiota disruption by broad-spectrum antibiotics is reversibly associated with decreased systemic cellular responsiveness towards LPS. The implications of these findings in a clinical setting remain to be determined.

Who Were the Early Adopters of Dabigatran?: An Application of Group-based Trajectory Models

BACKGROUND

Variation in physician adoption of new medications is poorly understood. Traditional approaches (eg, measuring time to first prescription) may mask substantial heterogeneity in technology adoption.

OBJECTIVE

Apply group-based trajectory models to examine the physician adoption of dabigratran, a novel anticoagulant.

METHODS

A retrospective cohort study using prescribing data from IMS Xponent™ on all Pennsylvania physicians regularly prescribing anticoagulants (n=3911) and data on their characteristics from the American Medical Association Masterfile. We examined time to first dabigatran prescription and group-based trajectory models to identify adoption trajectories in the first 15 months. Factors associated with rapid adoption were examined using multivariate logistic regressions.

OUTCOMES

Trajectories of monthly share of oral anticoagulant prescriptions for dabigatran.

RESULTS

We identified 5 distinct adoption trajectories: 3.7% rapidly and extensively adopted dabigatran (adopting in ≤3 mo with 45% of prescriptions) and 13.4% were rapid and moderate adopters (≤3 mo with 20% share). Two groups accounting for 21.6% and 16.1% of physicians, respectively, were slower to adopt (6-10 mo post-introduction) and dabigatran accounted for <10% share. Nearly half (45.2%) of anticoagulant prescribers did not adopt dabigatran. Cardiologists were much more likely than primary care physicians to rapidly adopt [odds ratio (OR)=12.2; 95% confidence interval (CI), 9.27-16.1] as were younger prescribers (age 36-45 y: OR=1.49, 95% CI, 1.13-1.95; age 46-55: OR=1.34, 95% CI, 1.07-1.69 vs. >55 y).

CONCLUSIONS

Trajectories of physician adoption of dabigatran were highly variable with significant differences across specialties. Heterogeneity in physician adoption has potential implications for the cost and effectiveness of treatment.

Antimicrobial-induced cognitive side effects

Introduction

Antimicrobial-induced cognitive side effects are often overlooked or underreported. Literature often reports symptoms of antimicrobial-induced cognitive impairment under more general blanket terms, such as neuropsychiatric side effects, neurotoxicity, or drug-induced delirium or encephalopathy.

Methods

A PubMed search using terms including antibiotics, antifungals, antivirals, antimalarials, side effects, cognitive, neurotoxicity, encephalopathy, and delirium was conducted. Respectively, symptoms of cognitive impairment were teased out of the multiple neurologic complications presented for each case and reported based on antimicrobial class. Articles were excluded if they focused solely on neuropsychiatric side effects such as seizures, psychosis, hallucinations, or mood disturbances, were conducted in animals, or involved antiretroviral medication therapies.

Results

Of over 50 case reviews, case reports, retrospective chart reviews, and prospective cohort studies analyzed, 25 were deemed appropriate for purposes of this review. Common antimicrobial-induced cognitive side effects for all antimicrobial classes included confusion, delirium, encephalopathy, and impaired concentration or attention. Recurring risk factors included, but were not limited to, older age and renal impairment. Mechanisms of cognitive impairment were relatively specific to each antimicrobial class.

Discussion

Awareness of the potential for antimicrobial-induced cognitive side effects, including the general time frame of symptom onset and symptom presentation, is critical in challenging patient cases. This review article aims to summarize the risk factors, clinical symptoms, mechanisms, and management of antimicrobial-induced cognitive side effects. Pharmacists can play a key role in prevention through adjustment of medications for renal or hepatic dysfunction, avoidance of polypharmacy, and knowledge of critical drug interactions that may precipitate cognitive decline.

Maternal Antibiotic Treatment Impacts Development of the Neonatal Intestinal Microbiome and Antiviral Immunity

Microbial colonization of the infant gastrointestinal tract (GIT) begins at birth, is shaped by the maternal microbiota, and is profoundly altered by antibiotic treatment. Antibiotic treatment of mothers during pregnancy influences colonization of the GIT microbiota of their infants. The role of the GIT microbiota in regulating adaptive immune function against systemic viral infections during infancy remains undefined. We used a mouse model of perinatal antibiotic exposure to examine the effect of GIT microbial dysbiosis on infant CD8(+) T cell-mediated antiviral immunity. Maternal antibiotic treatment/treated (MAT) during pregnancy and lactation resulted in profound alterations in the composition of the GIT microbiota in mothers and infants. Streptococcus spp. dominated the GIT microbiota of MAT mothers, whereas Enterococcus faecalis predominated within the MAT infant GIT. MAT infant mice subsequently exhibited increased and accelerated mortality following vaccinia virus infection. Ag-specific IFN-γ-producing CD8(+) T cells were reduced in sublethally infected MAT infant mice. MAT CD8(+) T cells from uninfected infant mice also demonstrated a reduced capacity to sustain IFN-γ production following in vitro activation. We additionally determined that control infant mice became more susceptible to infection if they were born in an animal facility using stricter standards of hygiene. These data indicate that undisturbed colonization and progression of the GIT microbiota during infancy are necessary to promote robust adaptive antiviral immune responses.

Unnecessary Antibiotics for Acute Respiratory Tract Infections: Association With Care Setting and Patient Demographics

Background.  Up to 40% of antibiotics are prescribed unnecessarily for acute respiratory tract infections (ARTIs). We sought to define factors associated with antibiotic overprescribing of ARTIs to inform efforts to improve practice. Methods.  We conducted a retrospective analysis of ARTI visits between 2006 and 2010 from the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey. Those surveys provide a representative sample of US visits to community-based physicians and to hospital-based emergency departments (EDs) and outpatient practices. Patient factors (age, sex, race, underlying lung disease, tobacco use, insurance), physician specialty, practice demographics (percentage poverty, median household income, percentage with a Bachelor's Degree, urban-rural status, geographic region), and care setting (ED, hospital, or community-based practice) were evaluated as predictors of antibiotic overprescribing for ARTIs. Results.  Hospital and community-practice visits had more antibiotic overprescribing than ED visits (odds ratio [OR] = 1.64 and 95% confidence interval [CI], 1.27-2.12 and OR = 1.59 and 95% CI, 1.26-2.01, respectively). Care setting had significant interactions with geographic region and urban and rural location. The quartile with the lowest percentage of college-educated residents had significantly greater overprescribing (adjusted OR = 1.41; 95% CI, 1.07-1.86) than the highest quartile. Current tobacco users were overprescribed more often than nonsmokers (OR = 1.71; 95% CI, 1.38-2.12). Patient age, insurance, and provider specialty were other significant predictors. Conclusions.  Tobacco use and a lower grouped rate of college education were associated with overprescribing and may reflect poor health literacy. A focus on educating the patient may be an effective approach to stewardship.

Tools for the Microbiome: Nano and Beyond

The microbiome presents great opportunities for understanding and improving the world around us and elucidating the interactions that compose it. The microbiome also poses tremendous challenges for mapping and manipulating the entangled networks of interactions among myriad diverse organisms. Here, we describe the opportunities, technical needs, and potential approaches to address these challenges, based on recent and upcoming advances in measurement and control at the nanoscale and beyond. These technical needs will provide the basis for advancing the largely descriptive studies of the microbiome to the theoretical and mechanistic understandings that will underpin the discipline of microbiome engineering. We anticipate that the new tools and methods developed will also be more broadly useful in environmental monitoring, medicine, forensics, and other areas.

Trends in the use of prescription antibiotics: NHANES 1999-2012

OBJECTIVES

The objectives of this study were: to examine trends in the use of prescription antibiotics overall and by population subgroups between 1999 and 2012; and to examine trends in the use of categories of antibiotics and individual antibiotics.

METHODS

Use of antibiotics was examined among 71 444 participants in the nationally representative National Health and Nutrition Examination Survey (NHANES; 1999-2012). Use of an antibiotic in the past 30 days was the main outcome variable. Analyses of trends were conducted overall and separately by population subgroups (i.e. age, sex, race/Hispanic origin, health insurance status and respiratory conditions) across four time periods (1999-2002, 2003-06, 2007-10 and 2011-12).

RESULTS

The percentage of the US population that used a prescription antibiotic in the past 30 days significantly declined from 6.1% in 1999-2002 to 4.1% in 2011-12 (P < 0.001). Declines were also identified for five age groups (0-1 year, 6-11 years, 12-17 years, 18-39 years and 40-59 years), both sexes, non-Hispanic white and non-Hispanic black persons, persons with and without insurance and among those who currently had asthma. Significant declines were also observed for three categories of antibiotics (penicillins, cephalosporins and macrolide derivatives). Of the most common antibiotics prescribed, only amoxicillin use decreased significantly.

CONCLUSIONS

Overall, there was a significant decline in the use of antibiotics between 1999-2002 and 2011-12. Due to concerns about antimicrobial resistance, it is important to continue monitoring the use of antibiotics.

Living conditions are associated with increased antibiotic resistance in community isolates of Escherichia coli

OBJECTIVES

The objective of this study was to measure the associations between domains of deprivation and antibiotic resistance of Escherichia coli.

METHODS

Routine surveillance data for antibiotic susceptibility of E. coli isolates were obtained from urine specimens taken from patients presenting with suspected urinary tract infection in 2010-12 to healthcare practitioners based in the community in Leeds and Bradford. Eight antibiotics were included in the analyses. Postcodes were linked to lower super output areas (average populations of 1500). The 2010 Indices of Deprivation were used as neighbourhood characteristics for each lower super output area. Multilevel logistic regression models were used to estimate the independent effect of structural components on the odds of resistance to each antibiotic.

RESULTS

With respect to living conditions, residence in the most-deprived areas compared with the least-deprived areas was associated with increased odds of antibiotic resistance for all eight antibiotics analysed. The magnitude of these associations included an OR of 2.04 (95% CI 1.03-3.07) for cefalexin, 2.16 (95% CI 1.16-4.05) for ciprofloxacin, 2.47 (95% CI 1.08-5.66) for nitrofurantoin and 1.33 (95% CI 1.07-1.75) for trimethoprim.

CONCLUSIONS

Social deprivation in the form of living conditions is associated with increased antibiotic resistance for E. coli. This evidence suggests there is a need for further individual-level studies to explore the potential mechanism for these associations.

Metabolic and metagenomic outcomes from early-life pulsed antibiotic treatment

Mammalian species have co-evolved with intestinal microbial communities that can shape development and adapt to environmental changes, including antibiotic perturbation or nutrient flux. In humans, especially children, microbiota disruption is common, yet the dynamic microbiome recovery from early-life antibiotics is still uncharacterized. Here we use a mouse model mimicking paediatric antibiotic use and find that therapeutic-dose pulsed antibiotic treatment (PAT) with a beta-lactam or macrolide alters both host and microbiota development. Early-life PAT accelerates total mass and bone growth, and causes progressive changes in gut microbiome diversity, population structure and metagenomic content, with microbiome effects dependent on the number of courses and class of antibiotic. Whereas control microbiota rapidly adapts to a change in diet, PAT slows the ecological progression, with delays lasting several months with previous macrolide exposure. This study identifies key markers of disturbance and recovery, which may help provide therapeutic targets for microbiota restoration following antibiotic treatment.

The potential recovery of the human gut microbiota after an antibiotic treatment, and its effects on our health, are poorly understood. Here, the authors use a mouse model mimicking paediatric antibiotic use to shed new light into these processes.

Dysbiotic drift: mental health, environmental grey space, and microbiota

Advances in research concerning the mental health implications of dietary patterns and select nutrients have been remarkable. At the same time, there have been rapid increases in the understanding of the ways in which non-pathogenic microbes can potentially influence many aspects of human health, including those in the mental realm. Discussions of nutrition and microbiota are often overlapping. A separate, yet equally connected, avenue of research is that related to natural (for example, green space) and built environments, and in particular, how they are connected to human cognition and behaviors. It is argued here that in Western industrial nations a ‘disparity of microbiota’ might be expected among the socioeconomically disadvantaged, those whom face more profound environmental forces. Many of the environmental forces pushing against the vulnerable are at the neighborhood level. Matching the developing microbiome research with existing environmental justice research suggests that grey space may promote dysbiosis by default. In addition, the influence of Westernized lifestyle patterns, and the marketing forces that drive unhealthy behaviors in deprived communities, might allow dysbiosis to be the norm rather than the exception in those already at high risk of depression, subthreshold (subsyndromal) conditions, and subpar mental health. If microbiota are indeed at the intersection of nutrition, environmental health, and lifestyle medicine (as these avenues pertain to mental health), then perhaps the rapidly evolving gut-brain-microbiota conversation needs to operate through a wider lens. In contrast to the more narrowly defined psychobiotic, the term eco-psychotropic is introduced.