Does current cefazolin dosing achieve adequate tissue and blood concentrations in obese women undergoing cesarean section?

Maternal-Fetal Exposure to Antibiotics: Levels, Mother-to-Child Transmission, and Potential Health Risks

Due to its widespread applications in various fields, antibiotics are continuously released into the environment and ultimately enter the human body through diverse routes. Meanwhile, the unreasonable use of antibiotics can also lead to a series of adverse outcomes. Pregnant women and developing fetuses are more susceptible to the influence of external chemicals than adults. The evaluation of antibiotic exposure levels through questionnaire surveys or prescriptions in medical records and biomonitoring-based data shows that antibiotics are frequently prescribed and used by pregnant women around the world. Antibiotics may be transmitted from mothers to their offspring through different pathways, which then adversely affect the health of offspring. However, there has been no comprehensive review on antibiotic exposure and mother-to-child transmission in pregnant women so far. Herein, we summarized the exposure levels of antibiotics in pregnant women and fetuses, the exposure routes of antibiotics to pregnant women, and related influencing factors. In addition, we scrutinized the potential mechanisms and factors influencing the transfer of antibiotics from mother to fetus through placental transmission, and explored the adverse effects of maternal antibiotic exposure on fetal growth and development, neonatal gut microbiota, and subsequent childhood health. Given the widespread use of antibiotics and the health threats posed by their exposure, it is necessary to comprehensively track antibiotics in pregnant women and fetuses in the future, and more in-depth biological studies are needed to reveal and verify the mechanisms of mother-to-child transmission, which is crucial for accurately quantifying and evaluating fetal health status.

Peripartum care of persons with obesity: a scoping review of recommendations and practical tools for implementation

OBJECTIVE

Despite the growing prevalence of obesity among reproductive aged persons in the USA, evidence-based guidelines for peripartum care are lacking. The objective of this scoping review is to identify obesity-related recommendations for peripartum care, evaluate grades of evidence for each recommendation, and identify practical tools (eg, checklists, toolkits, care pathways and bundles) to support their implementation in clinical practice.

DATA SOURCES

We searched MEDLINE, EMBASE, CINAHL, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov from inception to December 2020 for eligible studies addressing peripartum care in persons with obesity.

STUDY ELIGIBILITY CRITERIA

Inclusion criteria were published evidence-rated recommendations and practical tools for peripartum care of persons with obesity.

STUDY APPRAISAL AND SYNTHESIS METHODS

Pairs of independent reviewers extracted data (source, publication year, content and number of recommendations, level and grade of evidence, description of tool) and identified similarities and differences among the articles.

RESULTS

Of 18 315 screened articles, 18 were included including 7 articles with evidence-rated recommendations and 11 practical tools (3 checklists, 3 guidelines, 1 care bundle, 1 flowchart, 1 care pathway, 1 care map and 1 protocol). Thirteen of 39 evidence-rated recommendations were based on expert opinion. Recommendations related to surgical antibiotic prophylaxis and subcutaneous tissue closure at caesarean delivery received the highest grade of evidence. Some of the practical tools included a checklist from the USA regarding anticoagulation after caesarean delivery (evidence-supported recommendation), a bundle for surgical site infections after caesarean delivery in Australia (evidence did not support recommendation) and a checklist with content for several aspects of peripartum care from Canada (evidence supported seven of nine definitive recommendations).

CONCLUSION

The recommendations for peripartum care for persons with obesity are based on limited evidence and few practical tools for implementation exist. Future work should focus on developing practical tools based on high-quality studies.

Application of a Physiologically Based Pharmacokinetic Model to Predict Cefazolin and Cefuroxime Disposition in Obese Pregnant Women Undergoing Caesarean Section

Intravenous (IV) cefuroxime and cefazolin are used prophylactically in caesarean sections (CS). Currently, there are concerns regarding sub-optimal dosing in obese pregnant women compared to lean pregnant women prior to CS. The current study used a physiologically based pharmacokinetic (PBPK) approach to predict cefazolin and cefuroxime pharmacokinetics in obese pregnant women at the time of CS as well as the duration that these drug concentrations remain above a target concentration (2, 4 or 8 µg/mL or µg/g) in plasma or adipose tissue. Cefazolin and cefuroxime PBPK models were first built using clinical data in lean and in obese non–pregnant populations. Models were then used to predict cefazolin and cefuroxime pharmacokinetics data in lean and obese pregnant populations. Both cefazolin and cefuroxime models sufficiently described their total and free levels in the plasma and in the adipose interstitial fluid (ISF) in non–pregnant and pregnant populations. The obese pregnant cefazolin model predicted adipose exposure adequately at different reference time points and indicated that an IV dose of 2000 mg can maintain unbound plasma and adipose ISF concentration above 8 µg/mL for 3.5 h post dose. Predictions indicated that an IV 1500 mg cefuroxime dose can achieve unbound plasma and unbound ISF cefuroxime concentration of ≥8 µg/mL up to 2 h post dose in obese pregnant women. Re-dosing should be considered if CS was not completed within 2 h post cefuroxime administration for both lean or obese pregnant if cefuroxime concentrations of ≥8 µg/mL is required. A clinical study to measure cefuroxime adipose concentration in pregnant and obese pregnant women is warranted.

Understanding the pharmacokinetics of antibiotics in pregnancy: Is there a role for therapeutic drug monitoring? A narrative review

PURPOSE

Antibiotics are commonly used during pregnancy. However, physiological changes during pregnancy can affect the pharmacokinetics of drugs, including antibiotics, used during this period. Pharmacokinetic evaluations have shed light on how antibiotics are affected during pregnancy and have influenced dosing recommendations in this context. Methods: A narrative review was conducted and included reports providing data reflecting drug distribution and exposure in the context of pregnancy. Results: Pharmacokinetic parameters of antibiotics in pregnancy and transplacental passage of antibiotics are comprehensively presented. Conclusion: Knowledge about the impact on pharmacokinetics and fetal exposure is especially helpful for complicated or severe infections, including intra-amniotic infection and sepsis in pregnancy, where both mother and fetus are at risk. Further studies are warranted to consolidate the role of therapeutic drug monitoring in complicated or severe infections in pregnant patients.

Effect of Obesity on Clinical Failure of Patients Treated With β-Lactams

Background

Altered pharmacokinetics in obese patients raise concerns over worse clinical outcomes. This study assessed whether obese patients receiving a β-lactam have worse clinical outcomes compared to nonobese patients and to identify if therapeutic drug monitoring may be beneficial.

Methods

This multicenter, retrospective cohort included hospitalized adults admitted from July 2015 to July 2017 treated with a β-lactam as definitive monotherapy against a gram-negative bacilli for ≥72 hours. Patients were excluded if there was lack of source control or if polymicrobial infections required >1 antibiotic for definitive therapy. Patients were classified based on body mass index (BMI): nonobese (BMI ≤29.9 kg/m²) and obese (BMI ≥30.0 kg/m²). The primary outcome was clinical treatment failure, and secondary outcomes were hospital length of stay, inpatient all-cause mortality, and 30-day all-cause readmission.

Results

There were 257 (43.6%) obese patients and 332 (56.4%) nonobese patients included. The most common infections were urinary (50.9%) and respiratory (31.4%). Definitive treatment was driven by third-generation cephalosporins (46.9%) and cefepime (44.7%). Treatment failure occurred in 131 (51%) obese patients and 109 (32.8%) nonobese patients (P < .001). Obesity and respiratory source were independently associated with increased likelihood of treatment failure. Obese patients were hospitalized longer than nonobese patients (P = .002), but no differences were found for all-cause mortality (P = .117) or infection-related readmission (0 = 0.112).

Conclusions

Obese patients treated with β-lactams have higher rates of treatment failure and longer hospitalization periods than nonobese patients. Future studies are needed to assess the impact of therapeutic drug monitoring and specific dosing recommendations for targeted infection types.

Medications for Pregnant Women With Obesity: Special Considerations

Pregnant women with obesity are at increased risk of a multitude of complications of pregnancy and adverse perinatal outcomes. The risk of some of these complications, such as neural tube defects or preeclampsia, may be mitigated by some medications. Other complications, such as diabetes, venous thromboembolism, and infections, require treatment with medications. Given the changes in pharmacokinetics and pharmacodynamics during pregnancy, which is further enhanced by obesity, the optimal medication and its dose is often researched. This chapter further explores the different complications and common medications that women with obesity are likely to require.

Prophylactic perioperative cefuroxime levels in plasma and adipose tissue at the time of caesarean section (C-LACE): a protocol for a pilot experimental, prospective study with non-probability sampling to determine interpatient variability

Background

The aim of the C-LACE study is to measure cefuroxime concentration in plasma and adipose tissue of non-obese and obese pregnant women undergoing caesarean section.

Methods

This study plans to compare maternal cefuroxime concentrations (plasma and adipose tissue), at the time of skin incision and time of skin closure during a caesarean section from non-obese (body mass index BMI < 30 kg/m²) and obese (BMI ≥ 30 kg/m²) pregnant women. The incidence of post-surgical site infection will also be measured. At least 15 participants are required for each arm (non-obese vs obese) with a total of 30 participants. The study participants will be followed up between 30 and 40 days post-caesarean section to record details of any post-caesarean surgical infection to explore correlations between BMI, measured cefuroxime concentrations and post-caesarean infection rates.

Discussion

This pilot study will allow the development of a model testing the inter-patient variability in plasma and adipose tissue concentrations of cefuroxime. The results will facilitate the development of a larger study to determine whether differences in cefuroxime plasma and tissue concentration in obese and non-obese women can support the development of a physiologically based pharmacokinetic model. This model can then be used to propose dosing adjustments that can be used in a further trial to optimise cefuroxime dosing for women undergoing caesarean section.

Trial registration

ISRCTN Registry, ISRCTN17527512. Registered on 26 October 2020

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00794-3.

A Systematic Review and Meta-Analysis of Wound Complications after a Caesarean Section in Obese Women

(1) Background: Caesarean sections in obese patients are associated with an increased risk of surgical wound complications, including hematomas, seromas, abscesses, dehiscence, and surgical site infections. The aim of the present study is to perform a meta-analysis and systematic review of the current literature focusing on the strategies available to decrease wound complications in this population. (2) Methods: We reviewed the data available from the PubMed and the Science Direct databases concerning wound complications after caesarean sections in obese women. The following key words were used: “caesarean section”, “cesarean section”, “wound complication”, “wound morbidity”, and “wound infection”. A total of 540 papers were retrieved, 40 of which were selected for the final systematic review and whereas 21 articles provided data for meta-analysis. (3) Results: The conducted meta-analyses revealed that the use of prophylactic drainage does not increase the risk of wound complications in obese women after a caesarean sections (pooled OR = 1.32; 95% CI 0.64–2.70, p = 0.45) and that vertical skin incisions increase wound complications (pooled OR = 2.48; 95% CI 1.85–3.32, p < 0.01) in obese women, including extremely obese women. (4) Conclusions: Subcutaneous drainage does not reduce the risk of a wound complications, wound infections, and fever in obese women after caesarean sections. Negative prophylactic pressure wound therapy (NPWT) may reduce the risk of surgical site infections. The evidence of using a prophylactic dose of an antibiotic before the caesarean section is still lacking.

[Dosage of presurgical cefazolin in obese and non-obese patients. Does weight matter?]

Objetivo

. Actualmente no existe evidencia clara que guíe la dosificación de cefazolina en pacientes obesos en profilaxis quirúrgica. El objetivo fue evaluar la efectividad de este antibiótico con una dosis estándar de 2 g en la prevención de infección de herida quirúrgica (IHQ) en pacientes obesos en comparación con no obesos.

Material y métodos

. Revisión retrospectiva de varones ≥100 kg con cefazolina profiláctica entre 1 enero y 30 junio de 2019 en un hospital universitario en el servicio de traumatología. Los pacientes fueron estratificados en 2 grupos: obesos (≥ 100 kg e índice masa corporal (IMC)>30 kg/m²) y no obesos. Fueron excluidos aquellos que carecían de seguimiento en los 90 días posteriores a la intervención quirúrgica (IQ), aquellos con infección activa en el momento de la IQ o tratados con inmunosupresores. Se recogieron datos demográficos, altura, peso real, tabaquismo, diabetes, uso concomitante de inmunosupresores, datos de la IQ y presencia de infección hasta el día 90.

Resultados

. 57 pacientes fueron sometidos a IQ traumatológica con cefazolina profiláctica, 26 no obesos y 23 obesos. Ambos grupos presentaron diferencias estadísticamente significativas en cuanto a peso, IMC y uso de cefazolina post-IQ. No se observaron diferencias significativas en el resto de variables. Dos (8,7%) obesos y dos (7,7%) pacientes no obesos desarrollaron IHQ, siendo la diferencia entre los grupos estadísticamente no significativa, tras 63 días post-IQ de media.

Conclusión

. Este estudio demuestra que no existe diferencia significativa en IHQ con la dosis profiláctica de 2 g de cefazolina entre obesos y no obesos.

Reducing post-caesarean delivery surgical site infections: a narrative review

Surgical site infection complicates 1-10% of caesarean deliveries. With the rate of caesarean delivery increasing, it is important to identify effective measures of preventing surgical site infection and to consider their impact on maternal and neonatal outcomes. Compelling evidence supports the use of prophylactic antibiotics, prior to skin incision, to reduce surgical site infection. However, there remain international variations in terms of the recommended agent, dose and body weight-adjusted dosing. Advances in wound dressings are an evolving area of interest and surgical technique can influence outcomes. This narrative review explores pharmacological and non-pharmacological methods of preventing surgical site infection following caesarean delivery.

Efficacy of perioperative cefuroxime as a prophylactic antibiotic in women requiring caesarean section: A systematic review

Intravenous (IV) Cefuroxime (CFX) is widely used in Caesarean Section (CS) as a prophylactic antibiotic. The objective of this systematic review to compare CFX concentration in maternal blood and adipose tissue with the incidence of surgical site infection (SSI) following IV CFX in non-obese and obese women undergoing CS. A search in Medline, EMBASE, Cochrane, Web of Science, CINHAL Plus, Scopus and Google Scholar was conducted without language or date restrictions. Published articles or abstracts reporting CFX concentration or rates of SSI following CFX IV administration in adult women requiring CS were included. Studies were screened by title and abstract. Quality of studies was assessed via the ClinPK Statement checklist (Pharmacokinetics studies), or Joanna Briggs Institute Critical Appraisal Tools (SSI studies). The Cochrane Effective Practice and Organisation of Care checklist evaluated the risk of bias (SSI studies). There were no studies evaluating CFX concentrations in obese women undergoing CS. For non-obese women, CFX plasma concentrations ranged from 9.85 to 95.25 mg/L within 30-60 min of administration (1500 mg dose; 4 articles, n = 108 women). Plasma CFX concentrations were above the minimum inhibitory concentration (8 mg/L) for up to 3 h post-dose. No studies reported on CFX concentration in adipose tissue. Reported rates of SSI were 4.7% and 6.8% after administration of a single 1500 mg dose of CFX administrated after cord clamping (n = 144 women). There is limited data on pharmacokinetics of CFX for CS. There were no studies that reported CFX concentrations or SSI in obese women.

Obese patients have higher rates of polymicrobial and Gram-negative early periprosthetic joint infections of the hip than non-obese patients

Background

Obese patients are more likely to develop periprosthetic joint infection (PJI) after primary total joint arthroplasty. This study compared the clinical and microbiological characteristics of non-obese, obese and severely obese patients with early PJI, in order to ultimately optimize antibiotic prophylaxis and other prevention measures for this specific patient category.

Methods

We retrospectively evaluated patients with early PJI of the hip and knee treated with debridement, antibiotics and implant retention (DAIR) between 2006 and 2016 in three Dutch hospitals. Only patients with primary arthroplasties indicated for osteoarthritis were included. Early PJI was defined as an infection that developed within 90 days after index surgery. Obesity was defined as a BMI ≥30kg/m² and severe obesity as a BMI ≥35kg/m².

Results

A total of 237 patients were analyzed, including 64 obese patients (27.0%) and 62 severely obese patients (26.2%). Compared with non-obese patients, obese patients had higher rates of polymicrobial infections (60.3% vs 33.3%, p<0.001) with more often involvement of Enterococcus species (27.0% vs 11.7%, p = 0.003). Moreover, severely obese patients had more Gram-negative infections, especially with Proteus species (12.9% vs 2.3%, p = 0.001). These results were only found in periprosthetic hip infections, comprising Gram-negative PJIs in 34.2% of severely obese patients compared with 24.7% in obese patients and 12.7% in non-obese patients (p = 0.018).

Conclusions

Our results demonstrate that obese patients with early periprosthetic hip infections have higher rates of polymicrobial infections with enterococci and Gram-negative rods, which stresses the importance of improving preventive strategies in this specific patient category, by adjusting antibiotic prophylaxis regimens, improving disinfection strategies and optimizing postoperative wound care.

Can systemically administered antibiotics be detected in wound tissues and surfaces under negative pressure wound therapy?

In this study, we evaluated a new aspect of negative pressure wound therapy (NPWT) as an analytical tool for pharmacokinetic studies. Twenty-one patients with soft tissue defects scheduled to receive NPWT were included in this study. Concomitant to NPWT, all patients received intravenous moxifloxacin (MX). At different time intervals, blood plasma levels of MX were sampled and compared with synchronous concentrations of MX in the exudate obtained from the NPWT drainage system. Serial measurements were performed upon initiation of the therapy as well as in the steady state (after 5 days). At steady state, wound tissue was obtained intraoperatively. High-performance liquid-chromatography (HPLC) was used for analysis. At 1 hour post-administration, the exudate/plasma levels (mg/L) were 1.92/3.07; at 12 hours, 0.80/1.14; at 24 hours, 0.26/0.43; and at 120 hours (steady state), 0.42/0.47. There was a correlation between exudate and plasma levels reaching approximately 0.75. Until now, methods for pharmacokinetic studies concerning interstitial fluid are difficult to apply in the clinical context. The presented method showed limitations, but we believe that, after methodological improvements, measurements of substances in the interstitial fluid by means of NPWT are feasible.

Subcutaneous cefazolin to reduce surgical site infections in a porcine model

BACKGROUND

Surgical site infections (SSIs) pose a significant health and financial burden. A key aspect of appropriate prophylaxis is the administration of antibiotics intravenously (IV). However, subcutaneous administration of antibiotics is not well described in the literature. During surgery, we hypothesize that subcutaneous injection may provide better protection against SSIs. To better understand the kinetics after subcutaneous injection, we describe the serum concentrations of cefazolin in a porcine model.

MATERIALS AND METHODS

Juvenile mini-Yucatan pigs were administered 20 mL of 25 mg/kg cefazolin subcutaneously, and serial blood samples were taken for 3 h. Blood samples were analyzed for cefazolin concentration using chromatography. Pharmacokinetic data were calculated based on the blood serum concentrations.

RESULTS

Maximum serum concentrations of cefazolin were achieved 42.6 ± 2.0 min after the time of injection and were found to be 18.8 ± 7.4 μg/mL. The elimination rate constant was 0.0033 ± 0.0016 min^-1 and the half-life was 266 ± 149 min. The area under the curve was 4940 ± 1030 μg × min/mL. The relative bioavailability of subcutaneous injection was 95% +5%/-20%.

CONCLUSIONS

Subcutaneous administration of cefazolin achieves a significantly lower maximum serum concentration than IV injection. As a result, higher doses of antibiotic can be injected locally without incurring systemic toxicity. Subcutaneous administration will therefore result in higher concentrations of antibiotic for a longer time at the incision site compared with standard IV administration. This strategy of antibiotic delivery may be more effective in preventing SSIs. Further studies are needed to detail the exact effect of subcutaneous antibiotic injection on SSI rates.