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

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.

Practical Review on Delayed Primary Closure: Basic Science and Clinical Applications

Wound healing complications present a significant burden on both patients and health-care systems, and understanding wound healing principles is crucial across medical and surgical specialties to help mitigate such complications. One of these longstanding principles, specifically delayed primary closure (DPC), described as mechanically closing a wound after several days of secondary intention healing, lacks clear consensus on its definition, indications, and outcomes. This practical review examines wound healing fundamentals, focusing on DPC, its execution, indications, and comparative outcomes. A PubMed literature search was conducted to retrieve studies on DPC. Inclusion criteria included comparative studies assessing outcomes and complications between DPC and other closure techniques, as well as articles investigating DPC's underlying physiology. Twenty-three comparative studies met inclusion criteria. DPC wounds have significantly higher partial pressure of oxygen, higher blood flow, and higher rates of collagen synthesis and remodeling activity, all of which help explain DPC wounds' superior mechanical strength. DPC seems most beneficial in contaminated wounds, such as complicated appendectomies, postcardiac surgery wounds, and complicated abdominal wall reconstructions, where it has been associated with lower rates of surgical site infections. This practical review provides an evidence-based approach to DPC, its physiology, technique, and indications. Based on the existing literature, the authors recommend that DPC wounds should be dressed in saline/betadine soaks, changed and irrigated daily, with delayed closure lasting between 3 and 5 days or until the infection has resolved. The clearest indications for DPC are in the context of contaminated abdominal surgery and sternal wound dehiscence post cardiac surgery.

A Thermosensitive, Chitosan-Based Hydrogel as Delivery System for Antibacterial Liposomes to Surgical Site Infections

Prophylaxis and the treatment of surgical site infections (SSIs) with antibiotics frequently fail due to the antibiotic resistance of bacteria and the ability of bacteria to reside in biofilms (i.e., bacterial clusters in a protective matrix). Therefore, alternative antibacterial treatments are required to combat biofilm infections. The combination of diethyldithiocarbamate (DDC^-) and copper ions (Cu²⁺) exhibited antibiofilm activity against the staphylococci species associated with SSIs; however, the formation of a water-insoluble Cu(DDC)₂ complex limits its application to SSIs. Here, we describe the development and antibiofilm activity of an injectable gel containing a liposomal formulation of Cu(DDC)₂ and Cu²⁺ (lipogel). Lyophilized liposomes were incorporated into a mixture of chitosan (CS) and beta-glycerophosphate (βGP), and the thermosensitive gelling properties of CS-βGP and the lipogel were determined. The liposomes remained stable after lyophilization over six months at 4-6 °C and -20 °C. The sol-gel transition of the gel and lipogel occurred between 33 and 39 °C, independently of sterilization or storage at -20 °C. CS-βGP is biocompatible and the liposomes were released over time. The lipogel prevented biofilm formation over 2 days and killed 98.7% of the methicillin-resistant Staphylococcus aureus and 99.9% of the Staphylococcus epidermidis biofilms. Therefore, the lipogel is a promising new prophylaxis and treatment strategy for local application to SSIs.

RISK FACTORS FOR SURGICAL WOUND INFECTION AFTER ELECTIVE LAPAROSCOPIC CHOLECYSTECTOMY

BACKGROUND:

One of the ways to avoid infection after surgical procedures is through antibiotic prophylaxis. This occurs in cholecystectomies with certain risk factors for infection. However, some guidelines suggest the use of antibiotic prophylaxis for all cholecystectomies, although current evidence does not indicate any advantage of this practice in the absence of risk factors.

AIMS:

This study aims to evaluate the incidence of wound infection after elective laparoscopic cholecystectomies and the use of antibiotic prophylaxis in these procedures.

METHODS:

This is a retrospective study of 439 patients with chronic cholecystitis and cholelithiasis, accounting for different risk factors for wound infection.

RESULTS:

There were seven cases of wound infection (1.59%). No antibiotic prophylaxis regimen significantly altered infection rates. There was a statistically significant correlation between wound infection and male patients (p=0.013). No other analyzed risk factor showed a statistical correlation with wound infection.

CONCLUSIONS:

The nonuse of antibiotic prophylaxis and other analyzed factors did not present a significant correlation for the increase in the occurrence of wound infection. Studies with a larger sample and a control group without antibiotic prophylaxis are necessary.