New methods for the detection of orthopedic and other biofilm infections

Abstract

The detection and identification of bacteria present in natural and industrial ecosystems is now entirely based on molecular systems that detect microbial RNA or DNA. Culture methods were abandoned, in the 1980s, because direct observations showed that <1% of the bacteria in these systems grew on laboratory media. Culture methods comprise the backbone of the Food and Drug Administration-approved diagnostic systems used in hospital laboratories, with some molecular methods being approved for the detection of specific pathogens that are difficult to grow in vitro. In several medical specialties, the reaction to negative cultures in cases in which overt signs of infection clearly exist has produced a spreading skepticism concerning the sensitivity and accuracy of traditional culture methods. We summarize evidence from the field of orthopedic surgery, and from other medical specialties, that support the contention that culture techniques are especially insensitive and inaccurate in the detection of chronic biofilm infections. We examine the plethora of molecular techniques that could replace cultures in the diagnosis of bacterial diseases, and we identify the new Ibis technique that is based on base ratios (not base sequences), as the molecular system most likely to fulfill the requirements of routine diagnosis in orthopedic surgery.

The Limitations of In Vitro Experimentation in Understanding Biofilms and Chronic Infection

“…In vitro techniques are widely criticized for their incorporation of abiotic surfaces, which only have clinical relevance to a small number of implant-related infections [67][68][69]. However, the widespread use of abiotic surfaces is not surprising due to the difficulties of trying to mimic the complex multicellular topology of an in vivo surface.…”

“…Chronic foreign body infections of implants, stents and catheters, result in bacterial cells colonizing abiotic surfaces, leading to biofilm formation [67][68][69]. Catheters have been shown to constitute an environment whereby bacterial infections are able to develop into very thick biofilms [67,68,70].…”

Novel Biomarkers to Detect Infection in Revision Hip and Knee Arthroplasties

“…It is important to identify periprosthetic joint infections as early as possible [6,9,19,35,39]. Inflammatory biomarkers play a pivotal role in this diagnostic process.…”

Influence of Microorganisms on the Healing of Skin Grafts from Chronic Venous Leg Wounds

“…The system is based on base ratios (not base sequences) and can provide test results in six to seven hours (Ecker et al, 2008). The method was recently identified as the molecular system most likely to fulfill the requirements of routine diagnosis in orthopedic surgery (Costerton et al, 2011). …”