Tissue around catheters is a niche for bacteria associated with medical device infection

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Biomedical Engineering

Background:

• Catheter-associated infections (CAIs) pose a significant threat in healthcare settings.
• The primary sources of infection are often considered to be intraluminal or extraluminal migration of microorganisms along the catheter surface.

Purpose of the Study:

• To determine if pericatheter tissue serves as a bacterial reservoir contributing to CAIs.
• To investigate the role of pericatheter tissue in the pathogenesis of catheter-related infections.

Main Methods:

• A postmortem study involving 35 catheters and surrounding tissues from 18 deceased intensive care unit patients.
• Quantitative bacterial culturing and identification from catheter segments and adjacent tissues.
• Histological and immunohistochemical analysis of pericatheter tissues.

Main Results:

• Twenty-six percent of pericatheter tissue samples showed high bacterial loads, while corresponding catheter segments had minimal or no bacterial growth.
• Coagulase-negative staphylococci (e.g., Staphylococcus epidermidis) and Enterococcus faecalis were the predominant bacteria identified.
• Histology confirmed the presence of bacteria within the pericatheter tissue, both intercellularly and within host phagocytes.

Conclusions:

• Pericatheter tissue represents a significant, previously unrecognized niche for bacteria.
• This finding has implications for understanding the pathogenesis of CAIs.
• It may necessitate revised strategies for the prevention and treatment of catheter-associated infections.