Infectious Disease Updates

Is Your Hospital Bed Contaminated?

SOURCE: Witt LS, Howard-Anderson J, Prakash-Asrani R, et al. The role of the hospital bed in hospital-onset Clostridioides difficile: A retrospective study with mediation analysis. Infect Control Hosp Epidemiol 2024;45:559-603.

As facilities work hard to reduce the risk of hospital-onset Clostridioides difficile (HOCD), identifying gaps in hand cleansing, personal protective equipment (PPE), environmental cleaning, and infection control measures becomes crucial. The increased use of ultraviolet C (UVC) disinfection devices in healthcare settings has helped to reduce the risk of infection. The rate of HOCD within our facility significantly improved with the introduction of UVC in 2015 but despite extensive environmental cleaning efforts, HOCD cases continue to occur. Hospital beds are a particular concern because they are frequently moved around and are especially tricky to clean, with multiple moving parts, mattresses, and crevices that may remain contaminated, even when wiped down by a sporicidal sanitizing agent.

These authors assessed whether a hospital bed can serve as a risk factor for transmission of CD. A novel real-time radiofrequency- and infrared-light-based location system was used to track the movement of beds used in two academic hospital facilities from April 2018 to August 2019. Only beds that could be readily tracked for ≥ 75% of the days were eligible for analysis. Beds were considered “contaminated” when occupied by a person with CD, and remained “contaminated” in their model for 90 days. The clock would reset every time a new person with CD infection (CDI) was placed in the bed. Patients were diagnosed with CDI based on polymerase chain reaction testing. Patients testing positive > 3 days following admission were considered an HOCD case. An “exposed case” was defined as occurring while residing in a contaminated room or bed or diagnosed with HOCD within seven days of residing in a contaminated room or bed.

The facilities were a 529-bed hospital and a 751-bed hospital that provide tertiary care and solid organ and stem-cell transplantation. Only single rooms were included in the analysis. Rooms were cleaned on a daily basis with germicidal cleaner and received a terminal cleaning at patient exit. Rooms with a CD-positive patient had amplified cleaning measures using either OxyCide or BruTab and UV application. Mattress covers were semi-impermeable and were not removed from the bed frame during cleaning and UVC disinfection.

A total of 25,032 hospital encounters were identified, with 18,860 unique patients and 237 cases of HOCD (about seven cases per facility per month). Beds were moved an average of 6.7 times during the study period. Using a complex adjusted analysis, the risk of developing HOCD was increased if a patient resided in a contaminated bed (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.4-3.1); and the risk was further increased if they resided in both a contaminated bed and contaminated room (OR, 1.9). The median time between the prior CDI occupant of the bed to the new case of HOCD was 34.5 days. The authors then adjusted the analysis to reduce the window for “contamination of the bed” from 90 days to 60, 30, 14, and seven days. With each smaller window, the number of available patients was smaller, but nonetheless the risk remained statistically significant (adjusted analysis, OR, 1.5).

This study suggests that even with the best efforts at enhanced cleaning of rooms and beds — coupled with the use of UVC radiation — those hardy invisible C. diff spores may be occasionally missed (including on beds) and can persist in the environment and pose a risk to future occupants for up to 90 days. Newer methods for eradicating CD spores in hospital rooms, especially complex surfaces such as beds, are urgently needed. A limitation of this study was the lack of molecular data demonstrating genetic relatedness of strains.

The Surgical Skin Prep Debate Thickens

SOURCE: The PREP-IT Investigators; Sprague S, Slobogean G, Wells JL, et al. Skin antisepsis before surgical fixation of extremity fractures. N Engl J Med 2024;390;409-420.

The optimal surgical skin prep has been hotly debated, and most studies favor 2% chlorhexidine gluconate (CHG) in 70% isopropyl alcohol as being modestly superior to povidone iodine with alcohol solutions. For this reason, a number of associations and governing bodies have recommended the former for surgical site preparation. Orthopedic surgeons have argued that most of those studies were done in abdominal or gynecologic procedures, and not surgical cases involving orthopedic devices that theoretically may pose a different kind of risk.

As part of the Program of Randomized Trials to Evaluate Preoperative Antiseptic Skin Solutions in Orthopedic Trauma (PREP-IT), a large-scale cluster, randomized, crossover trial was performed at 25 hospitals in the United States. Hospitals were randomly assigned to a preoperative skin prep using either 0.7% iodine povacrylex (IP) in 74% isopropyl alcohol (3M Duraprep) or a solution of 2% CHG in 70% isopropyl alcohol (BD Chlora-Prep; or 3M SoluPrep) on all adult patients (≥ 18 years of age) with either closed or open fractures; and then every two months the two hospitals alternated interventions. The primary outcomes were superficial surgical incisional infection within 30 days or deep surgical infection within 90 days as defined by the Centers for Disease Control and Prevention National Healthcare Safety Network (NHSN) 2017 reporting criteria. Secondary outcomes included unplanned re-operation within one year and other adverse events.

Nearly 21,000 individuals were screened for inclusion in the study. The final closed fracture group included 6,785 adults with lower limb or pelvic fractures requiring surgical fixation. The average age was 54 years ± 20 years, slightly more than half were women (51%), and the most common fracture was femur (25%). Baseline characteristics were similar between the two intervention groups. Surgical site infections (SSIs) occurred in 2.4% of the IP group vs. 3.3% of the CHG group (odds ratio [OR], 0.74; 95% confidence interval [CI], 0.55-1.0; P = 0.049). Specifically, the risk of deep infection within 90 days was 29/3,205 (0.9%) vs. 54/3,272 (1.7%) between the IP and CHG groups, respectively; and the risk of organ space infection within 90 days was 28/3,205 (0.9%) vs. 27/3,272 (0.8%) between the IP and CHG groups, respectively. Unplanned surgical intervention within one year of the fracture repair was required in 5.5% of persons in the IP group vs. 5.9% in the CHG group (OR, 0.96; P = NS). More than half of the unplanned re-operations were for delayed union/non-union or problems with wound healing and not infection.

The final open fracture group involved 1,700 individuals with open upper or lower extremity fracture requiring surgical fixation. Fractures of hands were excluded, and the surgical repair had to occur within 72 hours of the fracture event. The average age was 44.6 years ± 18 years and nearly two-thirds were men (63.5%). Baseline characteristics were similar between the two intervention groups. Surgical site infection occurred in 6.5% of the IP group vs. 7.3% of the CHG group (OR, 0.86; P = 0.45). Unplanned re-operations occurred with similar frequency (16.1% of patients in the IP group vs. 14.5% of patients in the CHG group). Again, similar to the closed fracture group, more than half of the unplanned re-operations were for delayed union/non-union or problems with wound healing and not infection.

The authors drew several conclusions from this clinical trial. First, the risk of SSI, as defined by NHSN, with surgical fixation of closed fracture was statically significantly lower using IP compared with CHG, although similar findings could not be duplicated with open fracture fixation. The data for superficial, deep, and organ-space infection were combined in the final analysis, although the meat of this discussion really lies with preventing deep and organ space infection, the frequency of which appeared similar in this analysis. No apparent difference was observed between the two intervention groups for either the closed or open fracture groups with regard to unplanned re-operation, and more than half of the re-operations were not the result of infection. The authors postulated that the novel copolymer (povacrylex) formulation of the iodine solution may be an improvement over other iodine solutions. It is water-insoluble and can resist both blood and water challenge with diminished bacterial colony counts for up to 48 hours. It also was designed to better adhere to the surgical drape. However, open fractures often are extensively irrigated during the case, possibly mitigating the effect of either skin prep. Further, open fractures may involve contamination of deeper tissue not as amenable to skin prep.

Both groups were perhaps underpowered since estimates of infection were lower than anticipated (largely because those with infection occurring outside of the 30- or 90-day windows were censored). This was especially true for persons in the open fracture group, who remain at risk for infection for a longer time period. No data were provided on other measures used to reduce the risk for infection, such as pre-operative CHG showers and “nose-to-toes,” which have become standard pre-operative measures for many facilities. Many orthopedic surgeons also now perform intrawound irrigation using a variety of anti-infective and antiseptic solutions during the case, data which were not included. The skin prep debate continues.

Carol A. Kemper, MD, FIDSA, is Medical Director, Infection Prevention, El Camino Hospital Infectious Diseases, Palo Alto Medical Foundation.