Biofilm formation in periprosthetic joint infections

Abstract

Formation of microbial biofilms has long been implicated in the occurrence of periprosthetic joint infections (PJIs). Despite the widespread acknowledgment of the severity of these infections, much is still unknown regarding the underlying mechanisms of biofilm establishment and proliferation in the joint space. The presence of these resilient, complex communities poses many clinical challenges with respect to prevention, diagnosis, and treatment practices. Mature biofilms are known to be highly recalcitrant to antibiotic therapeutics as well as host immune system mediated clearance. A comprehensive understanding of biofilms in the unique joint environment at the molecular level will provide clinicians valuable insight into how best to combat them. As each stage in the process of biofilm establishment has the potential for clinical intervention, this review will provide a sequential analysis of the existing literature, following each step in the formation cycle. New insights into bacterial survival mechanisms from antimicrobial challenge and host immune defenses will be discussed. These new observations in the field may shed light on the early protection conferred upon entry into the joint space ultimately leading to the establishment of a mature biofilm. Additionally, standards of clinical diagnosis as well as current measures of prevention and treatment will be briefly discussed.

Keywords: Biofilm; diagnostics; orthopedics; periprosthetic joint infection (PJI); treatment.

Figure 1

General stages in device-associated biofilm formation. In vitro this process can take as short as 24 to 48, depending on species and nutrient and environmental conditions. It is not known how long this process takes in an infection, largely because symptoms often only present in the latter stages of biofilm formation.

Figure 2

Confocal microscopy of GFP-tagged Staphylococcal aureus synovial fluid-induced aggregates 1-hour post exposure. Strain kindly provided by Dr. Alexander Horswill, University of Colorado School of Medicine.