Biofilms, Biomaterials, and Device-related Infections
The chapter “A History of Biomaterials” at the start of this
book documents the development and design of indwelling
materials for medical and dental purposes. The primary
design criteria in the choice of materials were pragmatic and
based on the necessary mechanical properties required to
fashion a functional device. Orthopedic implants require
strong materials for load bearing, articulating surfaces such
as joints require durability and resistance to wear, stents and
shunts require flexibility and patency, and sutures require a
high tensile strength, yet must also be flexible enough for
intricate manipulation.
Indwelling devices, however, increase the risk of infection.
Catheter-associated urinary tract infection (CAUTI),
the most common health care-associated infection,
accounted for nearly 40% of all nosocomial infections
worldwide (Hooton et al., 2010). Prolonged catheter use
is the primary risk factor for developing CAUTI (www.
cdc.gov/hai/ca_uti/uti.html). Additionally, the incidence of
prosthetic joint (hip and knee) infections (PJIs) and cardiovascular
implantable device (CID) infections is increasing
dramatically (Xu et al., 2017). CIDs include cardiovascular
implantable electronic devices and ventricular assist devices,
and implantation is increasing with an aging population.
Although estimates vary with the types of devices, host
factors and underlying diseases, infection rates generally
increase with duration.
While for some procedures, such as orthopedic joint
arthroplasty, surgical-site infection rates are low (1%–2%)
(Kurtz et al., 2012), the ever-growing number of patients
undergoing these procedures translates to large numbers of
infection each year. By 2020, estimates suggest that there
will be 70,000 cases of infection in the United States alone
(Kurtz et al., 2012). Infection of artificial joints is especially
devastating, since oral or intravenous antibiotic therapy frequently
fails to resolve the infection, leaving the only course
of action to surgical debridement, or partial or total revision.
The formation of microbial biofilms on these devices
contributes significantly to device-related surgical site infections
rendering these infections extremely difficult to treat
with conventional topical or systemic antibiotic therapy.