Surgical Infections and Antibiotic Stewardship: In Need for New Directions

Biofunctional lipid nanoparticles for precision treatment and prophylaxis of bacterial infections

The lack of bacterial-targeting function in antibiotics and their prophylactic usage have caused overuse of antibiotics, which lead to antibiotic resistance and inevitable long-term toxicity. To overcome these issues, we develop neutrophil-bacterial hybrid cell membrane vesicle (HMV)-coated biofunctional lipid nanoparticles (LNP@HMVs), which are designed to transport antibiotics specifically to bacterial cells at the infection site for the effective treatment and prophylaxis of bacterial infection. The dual targeting ability of HMVs to inflammatory vascular endothelial cells and homologous Gram-negative bacterial cells results in targeted accumulation of LNP@HMVs in the site of infections. LNP@HMVs loaded with the antibiotic norfloxacin not only exhibit enhanced activity against planktonic bacteria and bacterial biofilms in vitro but also achieve potent therapeutic efficacy in treating both systemic infection and lung infection. Furthermore, LNP@HMVs trigger the activation of specific humoral and cellular immunity to prevent bacterial infection. Together, LNP@HMVs provide a promising strategy to effectively treat and prevent bacterial infection.

In vitro and in vivo evaluation of diethyldithiocarbamate with copper ions and its liposomal formulation for the treatment of Staphylococcus aureus and Staphylococcus epidermidis biofilms

Surgical site infections (SSIs) are mainly caused by Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis) biofilms. Biofilms are aggregates of bacteria embedded in a self-produced matrix that offers protection against antibiotics and promotes the spread of antibiotic-resistance in bacteria. Consequently, antibiotic treatment frequently fails, resulting in the need for alternative therapies. The present study describes the in vitro efficacy of the Cu(DDC)₂ complex (2:1 M ratio of diethyldithiocarbamate (DDC^-) and Cu²⁺) with additional Cu²⁺ against S. aureus and S. epidermidis biofilms in models mimicking SSIs and in vitro antibacterial activity of a liposomal Cu(DDC)₂ + Cu²⁺ formulation. The in vitro activity on S. aureus and S. epidermidis biofilms grown on two hernia mesh materials and in a wound model was determined by colony forming unit (CFU) counting. Cu²⁺-liposomes and Cu(DDC)₂-liposomes were prepared, and their antibacterial activity was assessed in vitro using the alamarBlue assay and CFU counting and in vivo using a Galleria mellonella infection model. The combination of 35 μM DDC^- and 128 μM Cu²⁺ inhibited S. aureus and S. epidermidis biofilms on meshes and in a wound infection model. Cu(DDC)₂-liposomes + free Cu²⁺ displayed similar antibiofilm activity to free Cu(DDC)₂ + Cu²⁺, and significantly increased the survival of S. epidermidis-infected larvae. Whilst Cu(DDC)₂ + Cu²⁺ showed substantial antibiofilm activity in vitro against clinically relevant biofilms, its application in mammalian in vivo models is limited by solubility. The liposomal Cu(DDC)₂ + Cu²⁺ formulation showed antibiofilm activity in vitro and antibacterial activity and low toxicity in G. mellonella, making it a suitable water-soluble formulation for future application on infected wounds in animal trials.

Six Long-Standing Questions about Antibiotic Prophylaxis in Surgery

Surgical site infections (SSIs) are the most common adverse event occurring in surgical patients. Optimal prevention of SSIs requires the bundled integration of a variety of measures before, during, and after surgery. Surgical antibiotic prophylaxis (SAP) is an effective measure for preventing SSIs. It aims to counteract the inevitable introduction of bacteria that colonize skin or mucosa into the surgical site during the intervention. This document aims to guide surgeons in appropriate administration of SAP by addressing six key questions. The expert panel identifies a list of principles in response to these questions that every surgeon around the world should always respect in administering SAP.

Antibacterial and Cytotoxicity Evaluation of New Hydroxyapatite-Based Granules Containing Silver or Gallium Ions with Potential Use as Bone Substitutes

The aim of the current work was to study the physicochemical properties and biological activity of different types of porous granules containing silver or gallium ions. Firstly, hydroxyapatites powders doped with Ga³⁺ or Ag⁺ were synthesized by the standard wet method. Then, the obtained powders were used to fabricate ceramic microgranules (AgM and GaM) and alginate/hydroxyapatite composite granules (AgT and GaT). The ceramic microgranules were also used to prepare a third type of granules (AgMT and GaMT) containing silver or gallium, respectively. All the granules turned out to be porous, except that the AgT and GaT granules were characterized by higher porosity and a better developed specific surface, whereas the microgranules had very fine, numerous micropores. The granules revealed a slow release of the substituted ions. All the granules except AgT were classified as non-cytotoxic according to the neutral red uptake (NRU) test and the MTT assay. The obtained powders and granules were subjected to various antibacterial test towards the following four different bacterial strains: Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli. The Ag-containing materials revealed high antibacterial activity.

Application of Operating Room Nursing Intervention to Incision Infection of Patients Undergoing Gastrointestinal Surgery Can Reduce Complications and Improve Gastrointestinal Function

Objective

To observe the influence of nursing intervention in operation rooms on incision infection of patients undergoing gastrointestinal surgery and the improvement of gastrointestinal function.

Methods

A total of 340 patients who underwent gastrointestinal surgery in our hospital from June 2020 to August 2021 were included. According to the random number table, they were divided into the conventional nursing group (n = 170) and the operating room nursing group (n = 170). The conventional nursing group was treated with routine nursing intervention, while the operating room nursing group was treated with operating room nursing intervention. The incision infection, healing, gastrointestinal function recovery, and complications in the two groups were compared, and the patient care satisfaction was recorded.

Results

The incidence of incision swelling, pain, and incision secretion in the operating room nursing group was significantly lower than that in the conventional nursing group (p < 0.05). The patients in the operating room nursing group had higher grade A healing than in the conventional nursing group, and lower grade B and grade C healing than in the conventional nursing group (p < 0.05). The time of anal exhaust, first defecation, and the time of gastric tube removal in the operating room nursing group were lower than those in the conventional nursing group (p < 0.05). The incidence of postoperative complications, such as incision infection, incision dehiscence, early inflammatory bowel adhesion, and abdominal abscess, in the operating room nursing group was lower than that in the conventional nursing group (p < 0.05). The total satisfaction degree in the operating room nursing group was significantly higher than that in the conventional nursing group (p < 0.05).

Conclusion

Nursing intervention in operation room can reduce complications and improve gastrointestinal function when applied to patients undergoing gastrointestinal surgery due to incision infection.

WHAT'S NEW IN INFECTION ON SURGICAL SITE AND ANTIBIOTICOPROPHYLAXIS IN SURGERY?

INTRODUCTION

Infection of the surgical site is the common complication, with significant rates of morbidity and mortality, representing a considerable economic problem for the health system.

OBJECTIVE

To carry out a narrative review of the literature on surgical site infection and the principles of antibiotic prophylaxis to update the knowledge of its use in surgery.

METHOD

Medline, Ovid, Google Scholar, National Library of Medicine (PubMed), Cochrane and SciELO were used for the research. The keywords used were "anti-bacterial agents"; "antibioticoprophylaxis" AND "surgical wound infection". The inclusion criteria were articles of recent publication, with full texts available and performed in humans.

RESULT

A total of 29 articles were evaluated and selected according to the eligibility criteria.

CONCLUSION

Infection of the surgical site is the most common postoperative complication. The key point of its prevention is the combination of several interventions that aim to reduce risk factors, such as: compliance with the new guidelines of the Center for Disease Control and Prevention; the principles of the use of prophylactic antibiotics; factors and risk index of the surgical site; administration time; duration and dosage of antibiotics. These data are available in this article.

Modifications of Hydroxyapatite by Gallium and Silver Ions-Physicochemical Characterization, Cytotoxicity and Antibacterial Evaluation

Hydroxyapatite (HA) powders enriched with silver or gallium ions or both were synthesized by two different routes: standard precipitation and the solid-state method. The powders were characterized by using several methods: inductively coupled plasma optical emission spectrometry (ICP-OES), powder X-ray diffractometry (PXRD), transmission electron microscopy (TEM), infrared spectroscopy (FT-IR) and solid-state nuclear magnetic resonance spectroscopy (ssNMR). The effects of enrichment of the HAs in Ag⁺ or Ga³⁺ or both on in vitro cytotoxicity and microbiological activity were discussed. PXRD experiments showed that the samples obtained by the wet method consisted of single-phase nanocrystalline HA, while the samples prepared via the solid-state method are microcrystalline with a small amount of calcium oxide. The introduction of higher amounts of silver ions was found to be more effective than enriching HA with small amounts of Ag⁺. Gallium and silver ions were found not to affect the lattice parameters. Ga³⁺ affected the crystallinity of the samples as well as the content of structural hydroxyl groups. Among samples synthesized by the wet method, only one (5Ag-HAw) was cytotoxic, whereas all Ga-containing samples obtained by the dry method showed cytotoxicity. In the preliminary antimicrobial test all the materials containing "foreign" ions showed high antibacterial activity.