Bacterial Colonisation of Suction Cannulas in Orthopaedic Surgery

INTRODUCTION

Osteoarticular infections represent a major complication in orthopaedic surgery. The aim is to identify the percentage of suction cannulas colonised and to determine the relationship between the time they are used in surgery and the colonisation of these cannulas.

MATERIALS AND METHODS

Descriptive and prospective study that analysed 546 suction cannulas used in clean orthopaedic surgery in a trauma centre, between November 2017 and March 2018. The distal end of the cannula was cultured to determine the colonisation rate.

RESULTS

7.3% of the cultured cannulas were positive for pathogens, the most frequent being Staphylococcus epidermidis at 27.5%. In addition, an association was found between colonisation and the length of time the cannula was used. The possibility of colonisation of cannulas used for between 60minutes or more, is greater than those used for less than 60minutes; between 60 and 90minutes the possibility is twice as high OR= 2.2 (CI:95% 1.1 - 4.1) and in cannulas used for more than 90minutes it is 8 times higher OR= 8.49 (CI:95% 1.77 - 40.86).

CONCLUSIONS

The colonisation rate of cannulas is lower than reported in the literature. The longer the cannula is used in surgery increases the risk of their colonisation. Follow-up studies are being considered to determine whether suction cannula colonisation is associated with increased postoperative infection.

Application of polymersomes engineered to target p32 protein for detection of small breast tumors in mice

Triple negative breast cancer (TNBC) is the deadliest form of breast cancer and its successful treatment critically depends on early diagnosis and therapy. The multi-compartment protein p32 is overexpressed and present at cell surfaces in a variety of tumors, including TNBC, specifically in the malignant cells and endothelial cells, and in macrophages localized in hypoxic areas of the tumor. Herein we used polyethylene glycol-polycaprolactone polymersomes that were affinity targeted with the p32-binding tumor penetrating peptide LinTT1 (AKRGARSTA) for imaging of TNBC lesions. A tyrosine residue was added to the peptide to allow for ¹²⁴I labeling and PET imaging. In a TNBC model in mice, systemic LinTT1-targeted polymersomes accumulated in early tumor lesions more than twice as efficiently as untargeted polymersomes with up to 20% ID/cc at 24 h after administration. The PET-imaging was very sensitive, allowing detection of tumors as small as ∼20 mm³. Confocal imaging of tumor tissue sections revealed a high degree of vascular exit and stromal penetration of LinTT1-targeted polymersomes and co-localization with tumor-associated macrophages. Our studies show that systemic LinTT1-targeted polymersomes can be potentially used for precision-guided tumor imaging and treatment of TNBC.