Strategies to Reduce Hospital-Acquired Infections

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SEM image depicting numerous clumps of methicillin-resistant <i>Staphylococcus aureus</i> bacteria. <i>Photo Credit: CDC/ Jeff Hageman, MHS.</i>
SEM image depicting numerous clumps of methicillin-resistant Staphylococcus aureus bacteria. Photo Credit: CDC/ Jeff Hageman, MHS.

Using enhanced disinfection strategies in a hospital environment decreases the spread of healthcare-associated pathogens such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant staphylococci, multidrug-resistant Acinetobacter spp, and Clostridium difficile. In a study published in the Lancet, Deverick J. Anderson, MD, MPH, from the Duke Infection Control Outreach Network at Duke University Medical Center, Durham, North Carolina, and colleagues found that patients were 10% to 30% less likely to acquire a multidrug-resistant organism or C difficile if the room they were admitted to was disinfected using an enhanced strategy.1

Dr Anderson and colleagues conducted a multicenter, cluster-randomized, crossover study (ClinicalTrials.gov identifier: NCT01579370) in 9 hospitals in the southeastern United States from April 2012 to July 2014. They evaluated 4 strategies for enhanced terminal room disinfection (disinfection of a room between occupying patients):

  • Reference: quaternary ammonium disinfectant (except C difficile, for which bleach was used)
  • UV (ultraviolet): Reference + UV (except C difficile, for which bleach + UV were used)
  • Bleach
  • Bleach + UV

The 4 strategies were used at each hospital in 4 consecutive 7-month periods. The sequence of strategies was randomly assigned (1:1:1:1) for each hospital.

There were 2 primary outcomes: incidence of infection or colonization with 4 target organisms (methicillin-resistant S aureus, vancomycin-resistant staphylococci, Acinetobacter, and C difficile) among exposed patients, and incidence of C difficile infection among exposed patients in the intention-to-treat populations.

Among the 21,395 patients included in the intention-to-treat population, the incidence of target organisms was reduced by 30% in the reference group when UV was added, whereas there was no statistically significant difference in either the bleach alone or in the bleach with UV group (Table 1).

Reference
(n=4916)
UV
(n=5178)
Bleach
(n=5438)
Bleach + UV
(n=5863)
Incident Cases 115 76 101 131
Rate
(per 10,000 exposure-days)
51.3 33.9 41.6 45.6
Relative Risk
(95% CI)
P value
0.70
(0.50-0.98)
.036
0.85
(0.69-1.04
.116
0.91
(0.76-1.09)
.303

This finding was further strengthened by a microbiological analysis of 92 randomly selected rooms after terminal disinfection "showed that all enhanced strategies decreased the bioburden of target organisms, but the largest decrease occurred in the UV group," noted the researchers.

The incidence of C difficile was not significantly different with the addition of UV light to bleach vs bleach alone (Table 2).

Table 2. Incidence of C difficile With and Without UV

Bleach Bleach + UV
Incident Cases 36 76
Rate
(per 10,000 exposure-days)
31.6 30.4
Relative Risk
(95% CI)
P value
1.0
(0.57-1.75)
.997

In a post hoc analysis excluding patients exposed to C difficile, the effect in the UV group was strengthened and the effect in the bleach with UV group became statistically significant.

In a commentary, Matthew P. Crotty, PharmD, and Patricia J. Jackson, both from the Methodist Dallas Medical Center, note that "previous studies of the use of UV light have shown decreases in hospital-acquired multidrug-resistant organisms and incidence of C difficile infection."2 Therefore, the lack of substantial decrease in C difficile infection in this study may be a result of the enhanced strategy used in the reference group itself:

  • Use of bleach
  • Compliance rate of roughly 90%
  • Use of microfiber cloths, which remove more bacteria than cotton and synthetic fiber cloths

The "location of the UV device outside of bathrooms for the single-stage cycle," in addition to the "requirement to only turn on the UV device, not necessarily complete the cycle, might also have affected these findings," wrote the commentators.

Further investigation is needed to interpret the lack of clinical effect of the use of UV light in preventing C difficile infection in this study. Likewise, although use of UV light showed a reduction in the other 3 target organisms, the commentators noted that "cost-benefit analyses for the use of UV light, including capital and maintenance costs...would be beneficial," as implementing UV light at large institutions would be costly, and additional staff will likely be needed to implement this protocol.

References

  1. Anderson DJ, Chen LF, Weber DJ, et al; CDC Prevention Epicenters Program. Enhanced terminal room disinfection and acquisition and infection caused by multidrug-resistant organisms and Clostridium difficile (the Benefits of Enhanced Terminal Room Disinfection study): a cluster-randomised, multicentre, crossover study [published online January 16, 2017]. Lancet. doi: 10.1016/S0140-6736(16)31588-4
  2. Crotty MP, Jackson PJ. Terminal room disinfection: how much BETR can it get? [published online January 16, 2017]. Lancet. doi: 10.1016/S0140-6736(16)32412-6
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