Adjustment of dosing of antimicrobial agents for bodyweight in adults

Vonoprazan Dual or Triple Therapy Versus Bismuth-Quadruple Therapy as First-Line Therapy for Helicobacter pylori Infection: A Three-Arm, Randomized Clinical Trial

BACKGROUND

We compared efficacy of vonoprazan-dual or triple therapies and bismuth-quadruple therapy for treatment-naive Helicobacter pylori (HP) infection in Southern China, where primary resistance rates of clarithromycin and levofloxacin are >30%.

METHODS

This was an investigator-initiated, three-arm, randomized clinical trial in Southern China. Between March 2022 and August 2023, treatment-naïve HP-infected adults were randomly assigned to receive one of three 14-day regimens (1:1:1 ratio): vonoprazan-dual (VA-dual; vonoprazan 20 mg twice daily and amoxicillin 1 g thrice daily), vonoprazan-triple (VAC-triple; vonoprazan 20 mg/amoxicillin 1 g/clarithromycin 500 mg twice daily), or bismuth-quadruple therapy containing bismuth, esomeprazole, tetracycline, and metronidazole. Primary outcome was noninferiority in HP eradication, evaluated by UBT 4-6 weeks post-treatment by intention-to-treat (ITT) and per-protocol (PP) analysis (based on subjects who completed 14-day treatment and rechecked UBT). Bonferroni-adjusted p-value of <0.017 was used to determine statistical significance.

RESULTS

A total of 298 subjects (mean age: 35.7 ± 8.4 years; male: 134 [45.0%]; VC-dual: 100, VAC-triple: 98, bismuth-quadruple: 100) were enrolled, and 292 (98.0%) had UBT rechecked. ITT analysis showed that both VA-dual (eradication rate of 96.0%) and VAC-triple therapies (95.9%) were noninferior to bismuth-quadruple therapy (92.0%) (difference: 4.0%, 95% CI: -2.9% to 11.5%, p < 0.001; and 3.9%, 95% CI: -3.1% to 11.5%, p < 0.001, respectively). PP analysis also revealed noninferiority (96.7% or 96.7% vs. 97.4%, with difference: -2.9% and -2.9%, p = 0.009 and 0.010, respectively). The frequency of adverse events was 39.0%, 56.1%, and 71.0% in VA-dual, VAC-triple, and bismuth-quadruple therapies, respectively.

CONCLUSIONS

VA-dual and VA-triple therapies are highly effective and noninferior to bismuth-quadruple therapy in Southern China. Given the lower adverse effects and fewer antibiotic use, VA-dual therapy is the preferred first-line treatment for HP infection.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (No. ChiCTR2200056375). Registered on February 4, 2022, https://www.chictr.org.cn/showproj.aspx?proj=14131.

Impact of body size on efficacy of high-dose dual therapy for Helicobacter pylori eradication

BACKGROUND

High-dose dual therapy (HDDT) is an emerging and promising therapeutic regime for Helicobacter pylori (H. pylori) eradication. However, the pharmacokinetics of the components of HDDT, amoxicillin and proton pump inhibitor, are likely to be affected by body size. In this study, we aimed to find out the impact of body size on the efficacy of HDDT.

METHODS

We collected the medical data of 385 treatment-naive patients infected with H. pylori who received HDDT (esomeprazole 20 mg and amoxicillin 750 mg four times daily) for 14 days from July 2020 to December 2021. The associations among the eradication efficacy, adverse events, and variables (sex, age, height, body weight, body mass index (BMI), body surface area (BSA), smoking, drinking, etc.) were analyzed respectively in our study. Among these factors, continuous variables were classified into categorical variables using the cut-off values which were calculated by receiver operating characteristic analysis.

RESULTS

The eradication rate of HDDT was 89.9%. There were 55 (14.3%) patients who occurred adverse events during the treatment. Patients with height <170.5 cm, body weight <60.5 kg, BMI <20.55 kg/m² , BSA <1.69 m² had a higher eradication rate (92.1% vs. 84.0%, 93.1% vs. 86.8%, 96.0% vs. 87.8%, 93.4% vs. 84.8%, all p < .05). The multivariate analysis showed that BSA ≥1.69 m² (OR 2.53, 95% CI: 1.28-4.99, p = .007) was the only independent predictor of eradication failure.

CONCLUSION

HDDT could achieve better eradication efficacy in patients with small BSA. Clinicians should be aware of the impact of BSA on the H. pylori eradication rate and pay more attention to patients with large BSA.

Ten-Day Vonoprazan-Amoxicillin Dual Therapy as a First-Line Treatment of Helicobacter pylori Infection Compared With Bismuth-Containing Quadruple Therapy

INTRODUCTION

No study has investigated the efficacy and safety of vonoprazan-amoxicillin dual therapy compared with bismuth quadruple therapy (B-quadruple). This study aimed to evaluate the efficacy and safety of 10-day vonoprazan-amoxicillin dual therapy as a first-line treatment of Helicobacter pylori infection compared with B-quadruple and to explore the optimal dosage of amoxicillin in the dual therapy.

METHODS

A total of 375 treatment-naive, H. pylori-infected subjects were randomly assigned in a 1:1:1 ratio into 3 regimen groups including VHA-dual (vonoprazan 20 mg twice/day + amoxicillin 750 mg 4 times/day), VA-dual (vonoprazan 20 mg + amoxicillin 1,000 mg twice/day), and B-quadruple (esomeprazole 20 mg + bismuth 200 mg + amoxicillin 1,000 mg + clarithromycin 500 mg twice/day). Eradication rates, adverse events (AEs), and compliance were compared between 3 groups.

RESULTS

The eradication rates of B-quadruple, VHA-dual, and VA-dual were 90.9%, 93.4%, and 85.1%, respectively, by per-protocol analysis; 89.4%, 92.7%, and 84.4%, respectively, by modified intention-to-treat analysis; 88.0%, 91.2%, and 82.4%, respectively, by intention-to-treat analysis. The efficacy of the VHA-dual group was not inferior to the B-quadruple group (P < 0.001), but VA-dual did not reach a noninferiority margin of -10%. The AEs rates of the B-quadruple group were significantly higher than those of the VHA-dual (P = 0.012) and VA-dual (P = 0.001) groups. There was no significant difference in medication compliance among 3 treatment groups (P = 0.995).

CONCLUSIONS

The 10-day VHA-dual therapy provided satisfactory eradication rates of >90%, lower AEs rates, and similar adherence compared with B-quadruple therapy as a first-line therapy for H. pylori infection. However, the efficacy of VA-dual therapy was not acceptable.

The Role of Obesity, Body Composition, and Nutrition in COVID-19 Pandemia: A Narrative Review

The coronavirus disease 2019 (COVID-19) pandemic has spread worldwide, infecting nearly 500 million people, with more than 6 million deaths recorded globally. Obesity leads people to be more vulnerable, developing worse outcomes that can require hospitalization in intensive care units (ICU). This review focused on the available findings that investigated the link between COVID-19, body composition, and nutritional status. Most studies showed that not only body fat quantity but also its distribution seems to play a crucial role in COVID-19 severity. Compared to the body mass index (BMI), visceral adipose tissue and intrathoracic fat are better predictors of COVID-19 severity and indicate the need for hospitalization in ICU and invasive mechanical ventilation. High volumes of epicardial adipose tissue and its thickness can cause an infection located in the myocardial tissue, thereby enhancing severe COVID-related myocardial damage with impairments in coronary flow reserve and thromboembolism. Other important components such as sarcopenia and intermuscular fat augment the vulnerability in contracting COVID-19 and increase mortality, inflammation, and muscle damage. Malnutrition is prevalent in this population, but a lack of knowledge remains regarding the beneficial effects aimed at optimizing nutritional status to limit catabolism and preserve muscle mass. Finally, with the increase in patients recovering from COVID-19, evaluation and treatment in those with Long COVID syndrome may become highly relevant.

Microneedle Aptamer-Based Sensors for Continuous, Real-Time Therapeutic Drug Monitoring

The ability to continuously monitor the concentration of specific molecules in the body is a long-sought goal of biomedical research. For this purpose, interstitial fluid (ISF) was proposed as the ideal target biofluid because its composition can rapidly equilibrate with that of systemic blood, allowing the assessment of molecular concentrations that reflect full-body physiology. In the past, continuous monitoring in ISF was enabled by microneedle sensor arrays. Yet, benchmark microneedle sensors can only detect molecules that undergo redox reactions, which limits the ability to sense metabolites, biomarkers, and therapeutics that are not redox-active. To overcome this barrier, here, we expand the scope of these devices by demonstrating the first use of microneedle-supported electrochemical, aptamer-based (E-AB) sensors. This platform achieves molecular recognition based on affinity interactions, vastly expanding the scope of molecules that can be sensed. We report the fabrication of microneedle E-AB sensor arrays and a method to regenerate them for multiple uses. In addition, we demonstrate continuous molecular measurements using these sensors in flow systems in vitro using single and multiplexed microneedle array configurations. Translation of the platform to in vivo measurements is possible as we demonstrate with a first E-AB measurement in the ISF of a rodent. The encouraging results reported in this work should serve as the basis for future translation of microneedle E-AB sensor arrays to biomedical research in preclinical animal models.

Systematic review and meta-analysis of risk factors for Mesh infection following Abdominal Wall Hernia Repair Surgery

BACKGROUND

Surgical Mesh Infection (SMI) after Abdominal Wall Hernia Repair (AWHR) represents a catastrophic complication. We performed a systematic review and meta-analysis to analyze the risk factors for SMI in the context of AWHR.

METHODS

PubMed, Embase, Scielo, and LILACS were searched without language or time restrictions from inception until June 2021. Articles evaluating the association between demographic, clinical, laboratory and surgical characteristics with SMI in AWHR were included.

RESULTS

23 studies were evaluated, comprising a total of 118,790 patients (98% males; mean age 56.5 years) with a mesh infection pooled prevalence of 4%. Significant risk factors for SMI were type 2 diabetes mellitus, obesity, smoking history, steroids use, ASA III/IV, laparotomy vs laparoscopy, emergency surgery, duration of surgery and onlay mesh position vs sublay. The quality of evidence was regarded as very low-moderate.

CONCLUSION

Several factors, highlighting sociodemographic characteristics, comorbidities, and the clinical scenario, may increase the risk of developing mesh infections in AWHR. The recognition and mitigation of these may significantly reduce mesh infection rates in this context.

Incidence and Risk Factors for Surgical Site Infection following Emergency Cesarean Section: A Retrospective Case-Control Study

OBJECTIVE

To assess the incidence, risk, and associated factors that contribute to an acquired surgical site infection (SSI) after emergency cesarean section (CS).

METHODS

This retrospective case-control study was conducted in an acute district general hospital in England with 206 patients (101 SSI patients and 105 non-SSI patients) who had an emergency CS in 2017. Grade of surgeon, smoking status, preoperative vaginal swab status (positive or negative), diabetes status, age, body mass index, membrane rupture to delivery interval, and length of surgery were recorded. Risk factors were identified using simple and multiple logistic regression.

RESULTS

Body mass index was significantly associated with SSI (odds ratio, 1.17; 95% confidence interval, 1.11 to 1.24; P < .001). Further, substantive nonsignificant associations were recorded between SSI and patient age and vaginal swab status.

CONCLUSIONS

Body mass index was the only significant risk factor for the development of an SSI after emergency CS, possibly because of the impact of excessive adipose tissue on the immune system and reduced effectiveness of antibiotics. Diabetes status, patient age, and preoperative vaginal swab status were not significantly associated with SSI. Improved guidelines and strategies for managing at-risk patients would enable clinicians to reduce the risk of SSI development. The importance of wound management including frequent wound cleaning, appropriate dressings, dressing changes, and education is highlighted. Future research on larger samples should be conducted to validate these findings.

The impact of obesity on immune response to infection: Plausible mechanisms and outcomes

Emerging data suggest an association between obesity and infectious diseases. Although the mechanisms underlying this link are not well established, a number of potential factors may be involved. Indeed, the obesity-related vulnerability to infectious diseases could be due to chronic low-grade inflammation, hyperglycemia, hyperinsulinemia, and hyperleptinemia, which lead to a weakening of both the innate and adaptive immune responses. In addition, obesity results in anatomical-functional changes by the mechanical obstacle of excessive adipose tissue that blunt the respiratory mechanisms and predisposing to respiratory infections. Subjects with obesity are also at risk of skin folds and sweat more profusely due to the thick layers of subcutaneous fat, favoring the proliferation of microorganisms and slowing the repair of wounds down. All these factors make subjects with obesity more prone to develop nosocomial infections, surgical site, skin and soft tissue infections, bacteremia, urinary tract infections, and mycosis. Furthermore, infections in subjects with obesity have a worse prognosis, frequently prolonging hospitalization time as demonstrated for several flu viruses and recently for COVID-19. Thus, the aim of this manuscript is to provide an overview of the current clinical evidence on the associations between obesity and infectious diseases highlighting physio pathological insights involved in this link.

Impact of body size on first-line Helicobacter pylori eradication success using vonoprazan and amoxicillin dual therapy

BACKGROUND

As a first-line therapy for Helicobacter pylori, dual therapy with vonoprazan and amoxicillin (VA-dual) provides an eradication rate similar to that of vonoprazan-based triple therapy. As the factors associated with the eradication rate of H. pylori with VA-dual are unknown,we investigated them in this study.

MATERIALS AND METHODS

Overall, 163 patients diagnosed with H. pylori infection received VA-dual (vonoprazan 20 mg twice daily and amoxicillin 750 mg twice daily for 7 d). The association between successful H. pylori eradication and the following patient clinical factors was analyzed: sex, age, height, weight, body surface area (BSA), body mass index (BMI), history of early gastric carcinoma and peptic ulcer, comorbidity of cirrhosis, alcohol consumption habit, smoking habit, common use of proton pump inhibitors, and concomitant use of drugs that are substratesof cytochrome P450 (CYP) 3A4. The association between post-eradication adverse events and clinical factors was analyzed retrospectively.

RESULTS

Successful H. pylori eradication was associated with a lower BSA (eradication rate: 90.8% in patients with BSA <1.723 vs. 79.6% in those with BSA ≥1.723; p = 0.045). The incidence of adverse events was higher in women than in men (adverse events: 40.0% in women vs. 19.4% in men; p = 0.004).

CONCLUSIONS

Successful H. pylori eradication with VA-dual was associated with the small body size of patients. This therapy may have to be adjusted per body size.

Development and validation of risk prediction score for incisional surgical site infection after appendectomy

Surgical site infection (SSI) is a challenging and resource-consuming healthcare problem. Predicting the onset of SSI beforehand can help prevent or minimize its incidence. The present study aimed to determine the independent predictors of incisional SSI after open appendectomy using a multivariate analysis and to establish a predictive risk score of SSI after appendectomy. Records of eligible patients who underwent open appendectomy were reviewed. The characteristics and treatment outcomes of patients were collected and analyzed. Significant association between different variables and SSI after appendectomy was examined by univariate analysis. Then, variables with a significant association with SSI were entered into a multivariate binary logistic regression analysis to determine the significant independent predictors of SSI. The study included 343 patients (51.3% female). Incisional SSI was recorded in 44 (12.8%) patients. Univariate analysis revealed five parameters with a significant association with SSI, including BMI > 30 kg/m² (p < 0.0001), diabetes mellitus (DM) (p = 0.0001), total leukocyte count (p = 0.04), free intraperitoneal fluid (p < 0.0001), and perforated/gangrenous appendicitis (p < 0.0001). After identifying four significant independent predictors of incisional SSI by binary logistic regression analysis, a predictive risk score was developed. The independent predictors of SSI were DM (OR = 6.05, p = 0.005), free intraperitoneal fluid (OR = 6.94, p = 0.0001), obesity (OR = 8.94, p = 0.0001), and perforated/gangrenous appendicitis (OR = 24.64, p = 0.0001). Four independent predictors of incisional SSI after open appendectomy were found after multivariate analysis. A predictive risk score of SSI was developed and included obesity, DM, free intraperitoneal fluid, and perforated/gangrenous appendicitis as predictors of SSI.

Impact of bodyweight-adjusted antimicrobial prophylaxis on surgical-site infection rates

Background

Antimicrobial prophylaxis (AMP) adjustment according to bodyweight to prevent surgical-site infections (SSI) is controversial. The impact of weight-adjusted AMP dosing on SSI rates was investigated here.

Methods

Results from a first study of patients undergoing visceral, vascular or trauma operations, and receiving standard AMP, enabled retrospective evaluation of the impact of bodyweight and BMI on SSI rates, and identification of patients eligible for weight-adjusted AMP. In a subsequent observational prospective study, patients weighing at least 80 kg were assigned to receive double-dose AMP. Risk factors for SSI, including ASA classification, duration and type of surgery, wound class, diabetes, weight in kilograms, BMI, age, and AMP dose, were evaluated in multivariable analysis.

Results

In the first study (3508 patients), bodyweight and BMI significantly correlated with higher rates of all SSI subclasses (both P < 0.001). An 80-kg cut-off identified patients receiving single-dose AMP who were at higher risk of SSI. In the prospective study (2161 patients), 546 patients weighing 80 kg or more who received only single-dose AMP had higher rates of all SSI types than a group of 1615 who received double-dose AMP (odds ratio (OR) 4.40, 95 per cent c.i. 3.18 to 6.23; P < 0.001). In multivariable analysis including 5021 patients from both cohorts, bodyweight (OR 1.01, 1.00 to 1.02; P = 0.008), BMI (OR 1.01, 1.00 to 1.02; P = 0.007) and double-dose AMP (OR 0.33, 0.23 to 0.46; P < 0.001) among other variables were independently associated with SSI rates.

Conclusion

Double-dose AMP decreases SSI rates in patients weighing 80 kg or more.

Surgical Infection Society Research Priorities: A Narrative Review of Fourteen Years of Progress

Background: In 2006, the Surgical Infection Society (SIS) utilized a modified Delphi approach to define 15 specific priority research questions that remained unanswered in the field of surgical infections. The aim of the current study was to evaluate the scientific progress achieved during the ensuing period in answering each of the 15 research questions and to determine if additional research in these fields is warranted. Methods: For each of the questions, a literature search using the National Center for Biotechnology Information (NCBI) was performed by the Scientific Studies Committee of the SIS to identify studies that attempted to address each of the defined questions. This literature was analyzed and summarized. The data on each question were evaluated by a surgical infections expert to determine if the question was answered definitively or remains unanswered. Results: All 15 priority research questions were studied in the last 14 years; six questions (40%) were definitively answered and 9 questions (60%) remain unanswered in whole or in part, mainly because of the low quality of the studies available on this topic. Several of the 9 unanswered questions were deemed to remain research priorities in 2020 and warrant further investigation. These included, for example, the role of empiric antimicrobial agents in nosocomial infections, the use of inotropes/vasopressors versus volume loading to raise the mean arterial pressure, and the role of increased antimicrobial dosing and frequency in the obese patient. Conclusions: Several surgical infection-related research questions prioritized in 2006 remain unanswered. Further high-quality research is required to provide a definitive answer to many of these priority knowledge gaps. An updated research agenda by the SIS is warranted at this time to define research priorities for the future.

Tailored Helicobacter pylori eradication therapy in obese patients undergoing bariatric surgery

OBJECTIVES

to compare the efficacy and safety of a tailored quadruple concomitant therapy based on body weight, with the same scheme but with fixed doses in obese patients undergoing bariatric surgery.

METHODS

a prospective study was performed of 104 obese patients.

RESULTS

the weight-based therapy group achieved significantly higher eradication rates in the intention-to-treat analysis; 86.3 % (95 % CI: 74.3-93.2) vs 66.1 % (95 % CI: 52.6-77.3), p < 0.05. Relative risk: 1.31 (95 % CI: 1.05-1.63). Discontinuations and adverse events were similar in both groups.

CONCLUSIONS

a tailored quadruple concomitant therapy based on body weight seems to be more effective than the standard quadruple concomitant therapy in obese patients.

Efficacy and Safety of Eravacycline in Obese Patients: A Post Hoc Analysis of Pooled Data From the IGNITE1 and IGNITE4 Clinical Trials

Background

The increasing prevalence of obesity worldwide merits an examination of the efficacy and safety profiles of agents dosed by weight.

Methods

Data for patients (n = 1037) were obtained from the pooled IGNITE1 and IGNITE4 randomized double-blind trials in which patients with complicated intra-abdominal infections received eravacycline 1 mg/kg (actual body weight [ABW]) every 12 hours or comparator (ertapenem 1 g every 24 hours or meropenem 1 g every 8 hours) intravenously. This post hoc analysis evaluated clinical cure rates, adverse events, and drug discontinuation rates stratified by body mass index (BMI) categories of BMI >40 kg/m² (Obese, Class III), BMI 35–39.9 kg/m² (Obese, Class II), BMI 30–34.9 kg/m² (Obese, Class I), BMI 25–29.9 kg/m² (Overweight), BMI 18.5–24.9 kg/m² (Healthy weight), and BMI <18.5 kg/m² (Underweight).

Results

Clinical cure rates were high across BMI categories and ranged from 82% to 94% in the eravacycline group and 88.5%–100% in the comparator group. Similar cure rates were observed among eravacycline-treated healthy weight (126/134; 94%), overweight (127/146; 87%), and obese (BMI ≥30 kg/m²; 110/129; 85.3%) patients. In the comparator group, a similar proportion of patients demonstrated clinical response (healthy weight [132/145; 91%], overweight [130/144; 90.3%], and obese [115/129; 89.1%]). Of the treatment-emergent adverse events that occurred in eravacycline-treated obese patients, a larger proportion were gastrointestinal-related (ie, nausea and vomiting); however, discontinuation rates were low and similar between eravacycline and carbapenems.

Conclusions

This post hoc analysis demonstrates the therapeutic utility and acceptable safety profile of eravacycline dosed by ABW in obese patients (BMI ≥30 kg/m²).

Antibiotic prescribing for common infections in UK general practice: variability and drivers

Objectives

To examine variations across general practices and factors associated with antibiotic prescribing for common infections in UK primary care to identify potential targets for improvement and optimization of prescribing.

Methods

Oral antibiotic prescribing for common infections was analysed using anonymized UK primary care electronic health records between 2000 and 2015 using the Clinical Practice Research Datalink (CPRD). The rate of prescribing for each condition was observed over time and mean change points were compared with national guideline updates. Any correlation between the rate of prescribing for each infectious condition was estimated within a practice. Predictors of prescribing were estimated using logistic regression in a matched patient cohort (1:1 by age, sex and calendar time).

Results

Over 8 million patient records were examined in 587 UK general practices. Practices varied considerably in their propensity to prescribe antibiotics and this variance increased over time. Change points in prescribing did not reflect updates to national guidelines. Prescribing levels within practices were not consistent for different infectious conditions. A history of antibiotic use significantly increased the risk of receiving a subsequent antibiotic (by 22%–48% for patients with three or more antibiotic prescriptions in the past 12 months), as did higher BMI, history of smoking and flu vaccinations. Other drivers for receiving an antibiotic varied considerably for each condition.

Conclusions

Large variability in antibiotic prescribing between practices and within practices was observed. Prescribing guidelines alone do not positively influence a change in prescribing, suggesting more targeted interventions are required to optimize antibiotic prescribing in the UK.

Calculated initial parenteral treatment of bacterial infections: Pharmacokinetics and pharmacodynamics

This is the third chapter of the guideline "Calculated initial parenteral treatment of bacterial infections in adults - update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. The chapter features the pharmacokinetic and pharmacodynamics properties of the most frequently used antiinfective agents.

Does obesity affect the short-term outcomes after cardiothoracic surgery in adolescents with congenital heart disease?

BACKGROUND

Obesity is a modifiable, independent risk factor for mortality and morbidity after cardiovascular surgery in adults. Our objective was to evaluate the impact of obesity on short-term outcomes in adolescents undergoing surgery for congenital heart disease (CHD).

METHODS

This retrospective chart review included patients 10-18 years of age who underwent CHD surgery. Our exclusion criteria were patients with a known genetic syndrome, heart transplantation, and patients with incomplete medical records. The clinical data collected included baseline demographics and multiple perioperative variables. Charting the body mass index in the Centers for Disease Control and Prevention growth curves, the entire cohort was divided into three categories: obese (>95th percentile), overweight (85th-95th percentile), and normal weight (<85th percentile). The composite outcome included survival, arrhythmias, surgical wound infection, acute neurologic injury, and acute kidney injury.

RESULTS

The study cohort (n = 149) had a mean standard deviation (SD), body mass index (BMI) of 22.6 ± 6.5 g/m2, and 65% were male. There were 27 obese (18.1%), 24 overweight (16.1%), and 98 normal weight (65.8%) patients. Twenty-seven (18%) patients had composite adverse outcomes. Overweight and obese patients had significantly higher adverse outcomes compared with normal weight patients (odds ratio (OR): 2.9; confidence interval (CI): 1-8.5, p = 0.04 and OR: 3; CI: 1-8.5, p = 0.03, respectively). In multivariate analysis, obesity was an independent predictor of adverse outcome in our cohort (p = 0.04).

CONCLUSIONS

Obesity is associated with short-term adverse outcome and increased health resource utilisation in adolescents following surgery for CHD. Further studies should evaluate if intervention in the preoperative period can improve outcomes in this population.

Sepsis Patients in Critical Care Units with Obesity: Is Obesity Protective?

Obesity is becoming a global health issue and its prevalence is increasing. It is associated with an increased incidence of illness and sepsis. While obesity is associated with increased morbidity and mortality, obesity has been found to be associated with improvement in mortality outcomes in sepsis when compared to leaner patients, a phenomenon described as an obesity paradox. However, the effect of obesity on mortality in adults requiring treatment for sepsis is unclear. Studies evaluating this effect are inconsistent and there is an increased morbidity still associated with obesity. As well, there are many limitations to these studies confounding interpretation. Future prospective studies minimizing bias and confounding factors are suggested to address this important clinical issue.

Association of Obesity With Septic Complications After Major Abdominal Surgery: A Secondary Analysis of the RELIEF Randomized Clinical Trial

IMPORTANCE

Body mass index (BMI) has been the most common obesity measure to assess perioperative risk; however, cardiometabolic risk is associated with the burden of visceral fat. Definitive evidence on the association of visceral fat measures, such as waist circumference and waist-to-hip ratio (WHR), with postoperative complications is lacking.

OBJECTIVE

To compare the value of waist circumference with the value WHR and BMI in predicting adverse outcomes, including major septic complications and persistent disability, following major abdominal surgery.

DESIGN, SETTING, AND PARTICIPANTS

This planned secondary analysis of the Restrictive vs Liberal Fluid Therapy for Major Abdominal Surgery (RELIEF) randomized clinical trial took place at 47 centers in 7 countries between October 2013 and September 2016, with 90-day follow-up. A total of 2954 adult RELIEF participants were coenrolled in this secondary analysis. Data analysis took place from December 2018 to September 2019.

EXPOSURES

Waist circumference, WHR, and BMI measurements.

MAIN OUTCOMES AND MEASURES

The primary outcomes were 30-day major septic complications and 90-day persistent disability or death.

RESULTS

Of 2954 eligible participants, 2755 were included (mean [SD] age, 65.9 [12.9] years; 1426 [51.8%] men) in the final analysis. A total of 564 participants (20.6%) experienced at least 1 major septic complication within 30 days after surgery (sepsis, 265 [9.7%]; surgical site infection, 409 [14.9%]; anastomotic leak, 78 [2.8%]; pneumonia, 104 [3.8%]). Waist circumference had a statistically significantly larger odds ratio (OR) and discrimination indices as well as a smaller prediction error than WHR or BMI for 30-day major septic complications or death (waist circumference: OR, 1.44; 95% CI, 1.28-1.62; P < .001; area under the receiver operating characteristic curve, 0.641; net reclassification index, 0.266; integrated discrimination improvement [score × 104], 152.98; Brier score, 0.162; WHR: OR, 1.15; 95% CI, 1.03-1.28; P = .01; area under the receiver operating characteristic curve, 0.621; net classification index, 0.199; integrated discrimination improvement [score × 104], 28.47; Brier score, 0.164; BMI: OR, 1.33; 95% CI, 1.17-1.50; P < .001; area under the receiver operating characteristic curve, 0.629; net reclassification index, 0.205; integrated discrimination improvement [score × 104], 85.61; Brier score, 0.163) but not for any other outcomes.

CONCLUSIONS AND RELEVANCE

In this secondary analysis of the RELIEF randomized clinical trial, waist circumference was observed to be superior to other adiposity indices in predicting 30-day major septic complications alone or in conjunction with death following elective major abdominal surgery. Findings suggest that waist circumference is a useful adiposity measure that should be incorporated in preoperative risk assessment for such complications.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01424150.

Electrochemical Aptamer-Based Sensors for Improved Therapeutic Drug Monitoring and High-Precision, Feedback-Controlled Drug Delivery

The electrochemical aptamer-based (E-AB) sensing platform appears to be a convenient (rapid, single-step, and calibration-free) and modular approach to measure concentrations of specific molecules (irrespective of their chemical reactivity) directly in blood and even in situ in the living body. Given these attributes, the platform may thus provide significant opportunities to render therapeutic drug monitoring (the clinical practice in which dosing is adjusted in response to plasma drug measurements) as frequent and convenient as the measurement of blood sugar has become for diabetics. The ability to measure arbitrary molecules in the body in real time could even enable closed-loop feedback control over plasma drug levels in a manner analogous to the recently commercialized controlled blood sugar systems. As initial exploration of this, we describe here the selection of an aptamer against vancomycin, a narrow therapeutic window antibiotic for which therapeutic monitoring is a critical part of the standard of care, and its adaptation into an electrochemical aptamer-based (E-AB) sensor. Using this sensor, we then demonstrate: (i) rapid (seconds) and convenient (single-step and calibration-free) measurement of plasma vancomycin in finger-prick-scale samples of whole blood, (ii) high-precision measurement of subject-specific vancomycin pharmacokinetics (in a rat animal model), and (iii) high-precision, closed-loop feedback control over plasma levels of the drug (in a rat animal model). The ability to not only track (with continuous-glucose-monitor-like measurement frequency and convenience) but also actively control plasma drug levels provides an unprecedented route toward improving therapeutic drug monitoring and, more generally, the personalized, high-precision delivery of pharmacological interventions.

Dose-Finding Studies Among Orphan Drugs Approved in the EU: A Retrospective Analysis

In the development process for new drugs, dose‐finding studies are of major importance. Absence of these studies may lead to failed phase 3 trials and delayed marketing authorization. In our study we investigated to what extent dose‐finding studies are performed in the case of orphan drugs for metabolic and oncologic indications. We identified all orphan drugs that were authorized until August 1, 2017. European Public Assessment Reports were used to extract the final dose used in the summary of product characteristics, involvement of healthy volunteers, study type, end points used, number of patients, number of doses, studies in special populations, and dose used for phase 3 studies. Each drug was checked for major objections and dose changes postmarketing. We included 49 orphan drugs, of which 28 were indicated for metabolic disorders and 21 for oncologic indications. Dose‐finding studies were performed in 32 orphan drugs, and studies in healthy volunteers in 26. The absence of dose‐finding studies was mostly due to the rarity of the disease. In this case the dose was determined based on factors such as animal studies or clinical experience. Dose‐related major objections were raised for 9 orphan drugs. Postmarketing dose‐finding studies were conducted in 18 orphan drugs, but dose changes were applied in only 2 drugs. In conclusion, dose‐finding studies in the case of metabolic and oncologic orphan drugs were conducted in the development programs of two thirds of orphan drugs. Dose‐finding studies performed postmarketing suggest that registered doses are not always optimal. It is thus important to perform more robust dose‐finding studies both pre‐ and postmarketing.

Obesity Increases the Risk of Postoperative Complications and Revision Rates Following Primary Total Hip Arthroplasty: An Analysis of 131,576 Total Hip Arthroplasty Cases

BACKGROUND

The aim of our study is to evaluate the association of body mass index (BMI) and the risk of postoperative complications, mortality, and revision rates following primary total hip arthroplasty given other potentially confounding patient characteristics in a large cohort study.

METHODS

Using nationwide billing data for inpatient hospital treatment of the biggest German healthcare insurance, 131,576 total hip arthroplasties in 124,368 patients between January 2012 and December 2014 were included. Outcomes were 90-day mortality, 1-year revision procedures (with and without removal or exchange of implants), 90-day surgical complications, 90-day femoral fractures, and overall complications. The effect of BMI on outcome was analyzed using multivariable logistic regression. Risk-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

BMI had a significant effect on overall complications (30-34 in kg/m²: OR 1.1, CI 1.0-1.2, P = .014; 35-39: OR 1.5, CI 1.3-1.6, P < .001; ≥40: OR 2.1, CI 1.9-2.3, P < .001; <30: reference). The OR for 1-year revision procedures (30-34: OR 1.2, CI 1.1-1.4, P = .001; 35-39: OR 1.6, CI 1.4-1.8, P < .001; ≥40: OR 2.4, CI 2.1-2.7, P < .001; <30: reference) and 90-day surgical complications increased with every BMI category. For mortality and periprosthetic fractures there was a higher risk only for patients with BMI ≥40.

CONCLUSION

BMI increases the risk of revision rates in a liner trend. Therefore, the authors believe that patients with a BMI >40 kg/m² should be sent to obesity medicine physicians in order to decrease the body weight prior elective surgery.

Effects of obesity on the outcome of pneumonia

Obesity is an important risk factor for both community-acquired pneumonia (CAP) and healthcare-associated pneumonia. In striking contrast, emerging data suggest that obesity is associated with more favorable outcome of pneumonia, a protective effect coined 'the obesity paradox'. Areas covered: The aim of the present review is to summarize the existing evidence on the outcome of pneumonia in obese patients and to discuss the mechanisms underpinning the association between obesity and pneumonia outcome. Several observational studies showed that obesity is associated with better outcome of CAP. In contrast, obesity represents a risk factor for adverse outcome in patients infected with pandemic influenza. Very limited data exist on the association between obesity and the outcome of healthcare-associated pneumonia. The pathophysiological mechanisms contributing to these paradoxical findings are unclear. Expert commentary: It is possible that residual confounding might partly explain the better outcome of pneumonia in obese patients. On the other hand, obesity might indeed offer a survival advantage in patients with acute diseases, including pneumonia. Clearly, larger and well-designed studies are needed to clarify the pathogenetic links between obesity and pneumonia outcome, which might represent novel therapeutic targets in the management of infectious diseases.

European Association for Cardio-Thoracic Surgery expert consensus statement on the prevention and management of mediastinitis

Mediastinitis continues to be an important and life-threatening complication after median sternotomy despite advances in prevention and treatment strategies, with an incidence of 0.25-5%. It can also occur as extension of infection from adjacent structures such as the oesophagus, airways and lungs, or as descending necrotizing infection from the head and neck. In addition, there is a chronic form of 'chronic fibrosing mediastinitis' usually caused by granulomatous infections. In this expert consensus, the evidence for strategies for treatment and prevention of mediatinitis is reviewed in detail aiming at reducing the incidence and optimizing the management of this serious condition.

[Should doses of antibiotics be adjusted?]

While we are confronted with the major increase in antibiotic resistance, the preservation of existing antibiotics has become an absolute necessity both to achieve therapeutic success and to limit the risks of the emergence of resistance. The optimization of antibiotic use and dosages must have a threefold objective: guarantee antibacterial efficacy, limit toxicities and limit emergence of resistant strains. However, with the increase in the number of multipathological patients, particularly those with renal or hepatic impairment, the increase in the number of patients with extreme weights and the use of antibiotics with narrower therapeutic margins, the adaptation of antibiotic dosages is becoming increasingly important. By reminding some principles of pharmacokinetics and pharmacodynamics of antibiotics (PK/PD), the necessary objectives for clinical effectiveness of most antibiotic classes are reviewed and several examples of situations where dosage adjustments are necessary will be given. In particular, adjustment of antibiotic dosages in obese patients will be discussed. Adaptation is not limited to the adaptation of the total daily dose. The PK/PD parameters also tell us that the mode of administration (intermittent versus continuous, number of injections per day, etc.) is also an essential point to consider. By taking examples concerning some molecules, infections and difficult clinical situations, we review situations in which dosage adjustments appear necessary.

The dangers of extreme body mass index values in patients with Clostridium difficile

PURPOSE

To examine the association between body mass index (BMI) and in-hospital mortality in patients presenting with Clostridium difficile infections in emergency department visits (ED) in the USA. Infected patients with extreme BMIs may have an elevated mortality risk, but prior studies examining this question have been too small to reach definitive conclusions.

METHODS

Data were from the Nationwide Emergency Department Sample (NEDS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality during 2012. NEDS records emergency department (ED) visits across the USA and provides statistical sampling weights to approximate a nationally representative sample of US hospital-based EDs. Inclusion criteria were adults age 18 or older with an ICD-9 code for C. difficile infection (008.45) and a documented body mass index ICD-9 V code (V85.x). Logistic regression was used to predict mortality after adjusting for demographic variables and chronic comorbidities defined by Elixhauser.

RESULTS

A weighted sample of 22,937 ED visits met all inclusion criteria. The cohort's mean age was 66. 64.6% were female. The unadjusted mortality rate was 6.5%. Patients with a BMI < 19 kg/m² had an adjusted odds ratio of 2.73; 95% CI (1.80, 4.16), p < 0.001 compared to patients with a BMI of 19.0-4.9 kg/m² (the referent category). In obese patients, only BMI values >40 kg/m² were associated with significantly greater mortality risk.

CONCLUSION

Being underweight (BMI < 19) or morbidly obese (BMI > 40) was associated with increased risk of in-hospital mortality in patients presenting with C. difficile infections.

Repeated Piperacillin-Tazobactam Plasma Concentration Measurements in Severely Obese Versus Nonobese Critically Ill Septic Patients and the Risk of Under- and Overdosing

OBJECTIVE

Obesity and critical illness modify pharmacokinetics of antibiotics, but piperacillin-tazobactam continuous IV infusion pharmacokinetics has been poorly studied in obese critically ill patients. We aimed to compare pharmacokinetics of piperacillin in severely obese and nonobese patients with severe sepsis or septic shock. We hypothesized that plasma concentration variability would expose the critically ill to both piperacillin under and overdosing.

METHODS

Prospective comparative study. Consecutive critically ill severely obese (body mass index, > 35 kg/m) and nonobese patients (body mass index, < 30 kg/m) were treated with 16 g/2 g/24 hr continuous piperacillin-tazobactam infusion. Piperacillin plasma concentration was measured every 12 hours over a 7-day period by high-pressure liquid chromatography. Unbound piperacillin plasma concentration and fractional time of plasma concentration spent over 64 mg/L (4-fold the minimal inhibitory concentration for Pseudomonas aeruginosa) were compared between the two groups. We performed 5,000 Monte Carlo simulations for various dosing regimens and minimal inhibitory concentration and calculated the probability to spend 100% of the time over 64 mg/L.

RESULTS

We enrolled 11 severely obese and 12 nonobese patients and obtained 294 blood samples. We did not observe a statistically significant difference in piperacillin plasma concentrations over time between groups. The fractional time over 64 mg/L was 64% (43-82%) and 93% (85-100%) in obese and nonobese patients, respectively, p = 0.027 with intra- and intergroup variability. Five nonobese and two obese patients experienced potentially toxic piperacillin plasma concentrations. When 64 mg/L was targeted, Monte Carlo simulations showed that 12 g/1.5 g/24 hr was inadequate in both groups and 16 g/2 g/24 hr was adequate only in nonobese patients.

CONCLUSION

Using a conventional dosing of 16 g/2 g/24 hr continuous infusion, obese patients were more likely than nonobese patients to experience piperacillin underdosing when facing high minimal inhibitory concentration pathogens. The present study suggests that piperacillin drug monitoring might be necessary in the sickest patients who are at the highest risk of unpredictable plasma concentration exposing them to overdose, toxicity, underdosing, and treatment failure.

Penetration of Ciprofloxacin and Amikacin into the Alveolar Epithelial Lining Fluid of Rats with Pulmonary Fibrosis

We determined the concentration-time profiles of ciprofloxacin and amikacin in serum and alveolar epithelial lining fluid (ELF) of rats with or without pulmonary fibrosis and investigated the effect of pulmonary fibrosis on the capacity for penetration of antimicrobials into the ELF of rats. Pulmonary fibrosis was induced in rats with a single intratracheal instillation of bleomycin. After intravenous injection of ciprofloxacin or amikacin, blood and bronchoalveolar lavage fluid samples were collected. Urea concentrations in serum and lavage fluid were determined using an enzymatic assay. Ciprofloxacin and amikacin concentrations were determined by high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry, respectively. The mean ratio of ELF to plasma concentrations of ciprofloxacin at each time point in the normal group did not significantly differ from that in the pulmonary fibrosis group. However, the ratio of the ciprofloxacin area under the concentration-time curve from 0 to 24 h (AUC_0-24) in ELF to the AUC_0-24 in plasma was 1.02 in the normal group and 0.76 in the pulmonary fibrosis group. The mean ELF-to-plasma concentration ratios of amikacin at each time point in the normal group were higher than those in the pulmonary fibrosis group, reaching a statistically significant difference at 1, 2, and 4 h. The ratio of the AUC_0-24 in ELF to the AUC_0-24 in plasma was 0.49 in the normal group and 0.27 in the pulmonary fibrosis group. In conclusion, pulmonary fibrosis can influence the penetration of antimicrobials into the ELF of rats and may have a marked effect on the penetration of amikacin than that of ciprofloxacin.

Diet-Induced Obesity Does Not Alter Tigecycline Treatment Efficacy in Murine Lyme Disease

Obese individuals more frequently suffer from infections, as a result of increased susceptibility to a number of bacterial pathogens. Furthermore, obesity can alter antibiotic treatment efficacy due to changes in drug pharmacokinetics which can result in under-dosing. However, studies on the treatment of bacterial infections in the context of obesity are scarce. To address this research gap, we assessed efficacy of antibiotic treatment in diet-induced obese mice infected with the Lyme disease pathogen, Borrelia burgdorferi. Diet-induced obese C3H/HeN mice and normal-weight controls were infected with B. burgdorferi, and treated during the acute phase of infection with two doses of tigecycline, adjusted to the weights of diet-induced obese and normal-weight mice. Antibiotic treatment efficacy was assessed 1 month after the treatment by cultivating bacteria from tissues, measuring severity of Lyme carditis, and quantifying bacterial DNA clearance in ten tissues. In addition, B. burgdorferi-specific IgG production was monitored throughout the experiment. Tigecycline treatment was ineffective in reducing B. burgdorferi DNA copies in brain. However, diet-induced obesity did not affect antibiotic-dependent bacterial DNA clearance in any tissues, regardless of the tigecycline dose used for treatment. Production of B. burgdorferi-specific IgGs was delayed and attenuated in mock-treated diet-induced obese mice compared to mock-treated normal-weight animals, but did not differ among experimental groups following antibiotic treatment. No carditis or cultivatable B. burgdorferi were detected in any antibiotic-treated group. In conclusion, obesity was associated with attenuated and delayed humoral immune responses to B. burgdorferi, but did not affect efficacy of antibiotic treatment.

Sepsis in Special Populations

Sepsis is recognized by the presence of physiologic and laboratory changes that reflect the inflammatory response to infection on cellular and systemic levels. Comorbid conditions, such as cirrhosis, end-stage renal disease, and obesity, alter patients' susceptibility to infection and their response to it once present. Baseline changes in vital signs and chronic medications often mask clues to the severity of illness. The physiologic, hematologic, and biochemical adjustments that accompany pregnancy and the puerperium introduce similar challenges. Emergency providers must remain vigilant for subtle alterations in the expected baseline for these conditions to arrive at appropriate management decisions.

A prospective observational cohort study in primary care practices to identify factors associated with treatment failure in Staphylococcus aureus skin and soft tissue infections

Background

The incidence of outpatient visits for skin and soft tissue infections (SSTIs) has substantially increased over the last decade. The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has made the management of S. aureus SSTIs complex and challenging. The objective of this study was to identify risk factors contributing to treatment failures associated with community-associated S. aureus skin and soft tissue infections SSTIs.

Methods

This was a prospective, observational study among 14 primary care clinics within the South Texas Ambulatory Research Network. The primary outcome was treatment failure within 90 days of the initial visit. Univariate associations between the explanatory variables and treatment failure were examined. A generalized linear mixed-effect model was developed to identify independent risk factors associated with treatment failure.

Results

Overall, 21% (22/106) patients with S. aureus SSTIs experienced treatment failure. The occurrence of treatment failure was similar among patients with methicillin-resistant S. aureus and those with methicillin-susceptible S. aureus SSTIs (19 vs. 24%; p = 0.70). Independent predictors of treatment failure among cases with S. aureus SSTIs was a duration of infection of ≥7 days prior to initial visit [aOR, 6.02 (95% CI 1.74–19.61)] and a lesion diameter size ≥5 cm [5.25 (1.58–17.20)].

Conclusions

Predictors for treatment failure included a duration of infection for ≥7 days prior to the initial visit and a wound diameter of ≥5 cm. A heightened awareness of these risk factors could help direct targeted interventions in high-risk populations.

Population Pharmacokinetics and Pharmacodynamics of Doripenem in Obese, Hospitalized Patients

Background: Doripenem population pharmacokinetics and dosing recommendations are limited in obesity. Objective: To evaluate the population pharmacokinetics and pharmacodynamics of doripenem in obese patients. Methods: Hospitalized adults with a body mass index (BMI) ≥ 40 kg/m2 or total body weight (TBW) ≥45.5 kg over their ideal body weight received doripenem 500 mg every 8 hours, infused over 1 hour. Population pharmacokinetic analyses were performed using NONMEM, and Monte Carlo simulations were performed for 5 intermittent and prolonged infusion dosing regimens to calculate probability of target attainment (PTA) at 40% and 100% fT>MIC (free drug concentrations above the minimum inhibitory concentration). Results: A total of 20 patients were studied: 10 in an intensive care unit (ICU) and 10 in a non-ICU. A 2-compartment model with first-order elimination best described the serum concentration-time data. Doripenem clearance (CL) was significantly associated with creatinine CL (CRCL), volume of the central compartment with TBW and ICU residence, and volume of the peripheral compartment with TBW ( P < 0.05). Using 40% fT>MIC, PTA was >90% for all simulated dosing regimens at MICs ≤2 mg/L. Using 100% fT>MIC, prolonged infusions of 1 g every 6 hours and 2 g every 8 hours achieved >90% PTA at MICs ≤2 mg/L. Conclusions: CRCL, ICU residence, and TBW are significantly associated with doripenem pharmacokinetics. Currently approved dosing regimens provide adequate pharmacodynamic exposures at 40% fT>MIC for susceptible bacteria in obese patients. However, prolonged infusions of larger doses are needed if a higher pharmacodynamic target is desired.

Predictors of community-associated Staphylococcus aureus, methicillin-resistant and methicillin-susceptible Staphylococcus aureus skin and soft tissue infections in primary-care settings

Skin and soft tissue infections (SSTIs) due to Staphylococcus aureus have become increasingly common in the outpatient setting; however, risk factors for differentiating methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) SSTIs are needed to better inform antibiotic treatment decisions. We performed a case-case-control study within 14 primary-care clinics in South Texas from 2007 to 2015. Overall, 325 patients [S. aureus SSTI cases (case group 1, n = 175); MRSA SSTI cases (case group 2, n = 115); MSSA SSTI cases (case group 3, n = 60); uninfected control group (control, n = 150)] were evaluated. Each case group was compared to the control group, and then qualitatively contrasted to identify unique risk factors associated with S. aureus, MRSA, and MSSA SSTIs. Overall, prior SSTIs [adjusted odds ratio (aOR) 7·60, 95% confidence interval (CI) 3·31-17·45], male gender (aOR 1·74, 95% CI 1·06-2·85), and absence of healthcare occupation status (aOR 0·14, 95% CI 0·03-0·68) were independently associated with S. aureus SSTIs. The only unique risk factor for community-associated (CA)-MRSA SSTIs was a high body weight (⩾110 kg) (aOR 2·03, 95% CI 1·01-4·09).

Pharmacokinetic and Pharmacodynamic Evaluation of a Weight-Based Dosing Regimen of Cefoxitin for Perioperative Surgical Prophylaxis in Obese and Morbidly Obese Patients

The objective of this study was to determine the pharmacokinetics and pharmacodynamics (PK/PD) of a weight-based cefoxitin dosing regimen for surgical prophylaxis in obese patients. Patients received a single dose of cefoxitin at 40 mg/kg based on total body weight. Cefoxitin samples were obtained over 3 h from serum and adipose tissue, and concentrations were determined by validated high-performance liquid chromatography. Noncompartmental pharmacokinetic analysis was performed, followed by Monte Carlo simulations to estimate probability of target attainment (PTA) for Staphylococcus aureus, Escherichia coli, and Bacteroides fragilis over 4-h periods postdose. Thirty patients undergoing bariatric procedures were enrolled. The body mass index (mean ± standard deviation [SD])was 45.9 ± 8.0 kg/m(2) (range, 35.0 to 76.7 kg/m(2)); the median cefoxitin dose was 5 g (range, 4.0 to 7.5 g). The mean maximum concentrations were 216.15 ± 41.80 μg/ml in serum and 12.62 ± 5.89 in tissue; the mean tissue/serum ratio was 8% ± 3%. In serum, weight-based regimens achieved ≥90% PTA (goal time during which free [unbound] drug concentrations exceed pathogen MICs [fT>MIC] of 100%) for E. coli and S. aureus over 2 h and for B. fragilis over 1 h; in tissue this regimen failed to achieve goal PTA at any time point. The 40-mg/kg regimens achieved higher PTAs over longer periods in both serum and tissue than did the standard 2-g doses. However, although weight-based cefoxitin regimens were better than fixed doses, achievement of desired pharmacodynamic targets was suboptimal in both serum and tissue. Alternative dosing regimens and agents should be explored in order to achieve more favorable antibiotic performance during surgical prophylaxis in obese patients.

The impact of patient and surgical factors on the rate of infection after primary total knee arthroplasty: an analysis of 64,566 joints from the New Zealand Joint Registry

AIMS

The aim of this study was to identify risk factors for prosthetic joint infection (PJI) following total knee arthroplasty (TKA).

PATIENTS AND METHODS

The New Zealand Joint Registry database was analysed, using revision surgery for PJI at six and 12 months after surgery as primary outcome measures. Statistical associations between revision for infection, with common and definable surgical and patient factors were tested.

RESULTS

A total of 64 566 primary TKAs have been recorded on the registry between 1999 and 2012 with minimum follow-up of 12 months. Multivariate analysis showed statistically significant associations with revision for PJI between male gender (odds ratio (OR) 1.85, 95% confidence interval (CI) 1.24 to 2.74), previous surgery (osteotomy (OR 2.45 95% CI 1.2 to 5.03), ligament reconstruction (OR 1.85, 95% CI 0.68 to 5.00)), the use of laminar flow (OR 1.6, 95% CI 1.04 to 2.47) and the use of antibiotic-laden cement (OR 1.93, 95% CI 1.19 to 3.13). There was a trend towards significance (p = 0.052) with the use of surgical helmet systems at six months (OR 1.53, 95% CI 1.00 to 2.34).

CONCLUSION

These findings show that patient factors remain the most important in terms of predicting early PJI following TKA. Furthermore, we found no evidence that modern surgical helmet systems reduce the risk of PJI and laminar flow systems may actually increase risk in TKA. The use of this registry data assists the estimation of the risk of PJI for individual patients, which is important for both informed consent and the interpretation of infection rates at different institutions.

TAKE HOME MESSAGE

Infection rates in TKA are related to both individual patient and surgical factors, and some modern methods of reducing infection may actually increase infection risk.

Body mass and weight thresholds for increased prosthetic joint infection rates after primary total joint arthroplasty

BACKGROUND AND PURPOSE

Obesity increases the risk of deep infection after total joint arthroplasty (TJA). Our objective was to determine whether there may be body mass index (BMI) and weight thresholds indicating a higher prosthetic joint infection rate.

PATIENTS AND METHODS

We included all 9,061 primary hip and knee arthroplasties (mean age 70 years, 61% women) performed between March 1996 and December 2013 where the patient had received intravenous cefuroxime (1.5 g) perioperatively. The main exposures of interest were BMI (5 categories: < 24.9, 25-29.9, 30-34.9, 35-39.9, and ≥ 40) and weight (5 categories: < 60, 60-79, 80-99, 100-119, and ≥ 120 kg). Numbers of TJAs according to BMI categories (lowest to highest) were as follows: 2,956, 3,350, 1,908, 633, and 214, respectively. The main outcome was prosthetic joint infection. The mean follow-up time was 6.5 years (0.5-18 years).

RESULTS

111 prosthetic joint infections were observed: 68 postoperative, 16 hematogenous, and 27 of undetermined cause. Incidence rates were similar in the first 3 BMI categories (< 35), but they were twice as high with BMI 35-39.9 (adjusted HR = 2.1, 95% CI: 1.1-4.3) and 4 times higher with BMI ≥ 40 (adjusted HR = 4.2, 95% CI: 1.8-9.7). Weight ≥ 100 kg was identified as threshold for a significant increase in infection from the early postoperative period onward (adjusted HR = 2.1, 95% CI: 1.3-3.6).

INTERPRETATION

BMI ≥ 35 or weight ≥ 100 kg may serve as a cutoff for higher perioperative dosage of antibiotics.

The Gut Bacteria-Driven Obesity Development

It is now well established that a healthy gut flora is largely responsible for the overall health of the host, while a perturbation in gut microbial communities can contribute to disease susceptibility. Obesity is a complex process involving genetic and environmental factors with an epidemiological burden that makes it a major public health issue. Studies of germ-free or gnotobiotic mice provided evidence that the diversity, as well as the presence and relative proportion of different microbes in the gut play active roles in energy homeostasis. Similarly, human studies showed that both the diversity of the microbiota and the Bacteroidetes/Firmicutes ratio are decreased in obese individuals. The 'obese microbiota' seems to be able to increase dietary energy harvest and favor weight gain and fat deposition. Although research in this field has just started and many of the available data are still conflicting, the results are providing exciting perspectives, and gut microbiota manipulation has already become a new target for both prevention and treatment of obesity.

Increased 3-gram cefazolin dosing for cesarean delivery prophylaxis in obese women

OBJECTIVE

The purpose of this study was to determine tissue concentrations of cefazolin after the administration of a 3-g prophylactic dose for cesarean delivery in obese women (body mass index [BMI] >30 kg/m(2)) and to compare these data with data for historic control subjects who received 2-g doses. Acceptable coverage was defined as the ability to reach the minimal inhibitory concentration (MIC) of 8 μg/mL for cefazolin.

STUDY DESIGN

We conducted a 2-phase investigation. The current phase is a prospective cohort study of the effects of obesity on tissue concentrations after prophylactic 3-g cefazolin doses at the time of cesarean delivery. Concentration data after 3-g were compared with data for historic control subjects who had received 2-g. Three grams of parenteral cefazolin was given 30-60 minutes before skin incision. Adipose samples were collected at both skin incision and closure. Cefazolin concentrations were determined with the use of a validated high-performance liquid chromatography assay.

RESULTS

Twenty-eight obese women were enrolled in the current study; 29 women were enrolled in the historic cohort. BMI had a proportionally inverse relationship on antibiotic concentrations. An increase of the cefazolin dose dampened this effect and improved the probability of reaching the recommended MIC of ≥8 μg/mL. Subjects with a BMI of 30-40 kg/m(2) had a median concentration of 6.5 μg/g (interquartile range [IQR], 4.18-7.18) after receiving 2-g vs 22.4 μg/g (IQR, 20.29-34.36) after receiving 3-g. Women with a BMI of >40 kg/m(2) had a median concentration of 4.7 μg/g (IQR, 3.11-4.97) and 9.6 μg/g (IQR, 7.62-15.82) after receiving 2- and 3-g, respectively. With 2 g of cefazolin, only 20% of the cohort with a BMI of 30-40 kg/m(2) and none of the cohort with a BMI of >40 kg/m(2) reached an MIC of ≥8 μg/mL. With 3-g, all women with a BMI of 30-40 kg/m(2) reached target MIC values; 71% of the women with a BMI of >40 kg/m(2) attained this cutoff.

CONCLUSION

Higher adipose concentrations of cefazolin were observed after the administration of an increased prophylactic dose. This concentration-based pharmacology study supports the use of 3 g of cefazolin at the time of cesarean delivery in obese women. Normal and overweight women (BMI <30 kg/m(2)) reach adequate cefazolin concentrations with the standard 2-g dosing.

Impact of obesity on the risk of wound infection following surgery: results from a nationwide prospective multicentre cohort study in England

We sought to assess the impact of body mass index on the risk of surgical site infection in a prospective cohort study of 206 National Health Service (NHS) hospitals in England between 2007 and 2011. Body mass index was available for 159,720 of 350,089 operations among patients undergoing abdominal hysterectomy, coronary artery bypass graft, hip replacement, knee replacement, or large-bowel surgery. Among these patients, the risk of surgical site infection ranged from 0.65% for knee replacement to 11.04% for large-bowel surgery. Overall, 127,512 (79.8%) patients were overweight or obese (body mass index of ≥25 kg/m(2)). Obesity was associated with a 1.1-fold to 4.4-fold increase in the adjusted odds of developing surgical site infection as compared with normal weight, depending on the type of surgery. The population-attributable fraction (PAF) for body mass index was greatest in overweight (body mass index of 25.0-29.9 kg/m(2)) patients undergoing coronary artery bypass graft, accounting for 15% of their overall risk of surgical site infection (PAF 0.15; 95% CI 0.09-0.22). Being overweight or obese substantially increased the likelihood of patients developing surgical site infection. Given the increasingly high proportion of the surgical population who are overweight, this is likely to place a considerable additional burden on the NHS. Strategies for mitigating this excess risk need to be found.

The art of targeting gut microbiota for tackling human obesity

Recently, a great deal of interest has been expressed regarding strategies to tackle worldwide obesity because of its accelerated wide spread accompanied with numerous negative effects on health and high costs. Obesity has been traditionally associated with an imbalance in energy consumed when compared to energy expenditure. However, growing evidence suggests a less simplistic event in which gut microbiota plays a key role. Obesity, in terms of microbiota, is a complicated disequilibrium that presents many unclear complications. Despite this, there is special interest in characterizing compositionally and functionally the obese gut microbiota with the help of in vitro, animal and human studies. Considering the gut microbiota as a factor contributing to human obesity represents a tool of great therapeutic potential. This paper reviews the use of antimicrobials, probiotics, fecal microbial therapy, prebiotics and diet to manipulate obesity through the human gut microbiota and reveals inconsistencies and implications for future study.

Cellulitis in Obesity

Purpose: Cellulitis in obese patients is associated with increased rates of treatment failure compared to those with normal body mass index (BMI); however, patients have not been extensively studied in the outpatient environment or stratified based on range of obesity and associated risk factors. This study looked at antibiotic dosing and treatment failure in the obese population from the primary care perspective and accounts for BMI range, weight, comorbid diabetes, and tobacco use. Methods: This study was a retrospective chart review of 637 adult primary care patients designed to evaluate rates of treatment failure of outpatient cellulitis among patients of varying BMI. Treatment failure was defined as ( a) hospital admission for intravenous antibiotics, ( b) prolonged antibiotic course, or ( c) requiring a different antibiotic after initial course. Results: Adverse outcomes were not statistically significant between normal BMI and those with BMI ≥40 kg/m2. A subset of patients with a BMI ≥50 kg/m2 was noted to have approximately twice the rate of adverse outcomes as the normal BMI group. While controlling for age, gender, race, diagnosis of diabetes mellitus, and tobacco use, a BMI of ≥50 kg/m2 and a weight ≥120 kg was associated with adverse outcomes with an odds ratio of 2.440 (95% CI, 1.260-4.724; P = .008) and 2.246 (95% CI, 1.154-4.369; P = .017), respectively. Conclusions: Patients with cellulitis weighing >120kg or with a BMI ≥50 kg/m2 were at greatest risk for treatment failure in the outpatient setting, even when controlling for comorbid diabetes and tobacco use. As morbid obesity continues to become more prevalent, it becomes imperative that primary care physicians have better antibiotic dosing guidelines to account for the physiologic effects of obesity to minimize the risk of increased morbidity, health care costs, and antibiotic resistance.