Usefulness of screening for Candida auris colonisation in international patients admitted to a large university hospital

Horizontal versus vertical strategies for infection prevention: current practices and controversies

PURPOSE OF REVIEW

Healthcare-associated infections (HAIs) represent a major burden on healthcare facilities. Effective infection prevention strategies are essential to prevent the spread of HAIs. These can be broadly classified as vertical and horizontal interventions. Through this review, we aim to assess the merits of these strategies.

RECENT FINDINGS

Vertical strategies include active surveillance testing and isolation for patients infected or colonized with a particular organism. These strategies are beneficial to curb the spread of emerging pathogens and during outbreaks. However, the routine use of contact precautions for organisms such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus remains controversial. Horizontal interventions are larger-scale and reduce HAIs by targeting a common mode of transmission shared by multiple organisms. Among these, hand hygiene, chlorhexidine gluconate bathing of select patients and environmental decontamination are the most high-yield and must be incorporated into infection prevention programs. As antimicrobial stewardship is also an effective horizontal strategy, antimicrobial stewardship programs must operate in synergy with infection prevention programs for maximal impact.

SUMMARY

Overall, horizontal interventions are considered more cost-effective and have a broader impact. Infection control programs may opt for a combination of vertical and horizontal strategies based on local epidemiology and available resources.

Proposal for a screening protocol for Candida auris colonization

BACKGROUND

Candida auris is an emerging multidrug-resistant yeast which can cause severe infection in hospitalized patients. Since its first detection in 2009, C. auris has spread globally. The control and elimination of this pathogen in a hospital setting is particularly challenging because of its ability to form biofilms, allowing for long-term patient colonization and persistence in the environment. Identification of C. auris from cultures is difficult due to the morphologic similarities to other yeasts, its slow growth, and the low culture sensitivity when using standard agars and temperatures.

AIM

We have developed a screening protocol for C. auris colonization using an in-house-developed polymerase chain reaction (PCR), combined with confirmatory culture in optimized conditions.

METHODS

C. auris-specific primers and probe were developed, targeting the internal transcribed spacer (ITS) region, and specificity was confirmed in silico using the BLAST tool. The PCR was validated using a panel of 12 C. auris isolates and 103 isolates from 22 other Candida species and was shown to be 100% accurate. The limit of detection of the assay was determined at approximately four cells per PCR.

FINDINGS

C. auris screening was introduced on February 15th, 2023, and was used for patients who had been admitted to a healthcare facility abroad in the two months prior to admission to our hospital. The screening protocol included swabs from nose, throat, rectum, axilla, and groin. In the first eight months, 199 patients were screened and seven were found positive (4%).

CONCLUSION

Our proposed screening protocol may contribute to control C. auris in hospitals.