Bacterial resistance to antibiotics has been documented since the first decade of widespread antibiotic use in the 1930s. Due to evolution and overuse of antibiotics, many pathogenic bacteria have developed resistance to multiple antibiotics and are known as multidrug-resistant (MDR) bacteria or "superbugs" (Davies & Davies, 2010). More recently, the emergence of antifungal resistance has been recognized as a threat to public health (McCarthy et al., 2017). Antifungal-resistant infections are increasing due to the widespread use of antifungal agents both in medicine and agriculture (Kontoyiannis, 2017). The most common fungal infections among hospitalized patients are invasive candidiasis (Kullberg & Arendrup, 2015). Candida infections are particularly problematic among immunocompromised patients (Kragelund, 2017). Cancer and chemotherapy treatments increase the risk for fungal infections, with greater risk among patients with hematologic cancers (Centers for Disease Control and Prevention [CDC], 2017a). According to the CDC (2017b), there are an estimated 46,000 candida infections associated with hospital care in the United States annually. Drug-resistant candida in the bloodstream leads to the death of up to 30% of those infected (CDC, 2013).
Of the more than 20 species of candida, the most common candida infections are caused by Candida albicans (CDC, 2017b). The second most common cause of invasive candida infections in the United States is Candida glabrata (C. glabrata), which develops resistance after exposure to antifungal medications (Arendrup & Patterson, 2017). Among patients with C. glabrata infections, 12% to 18% are infected with fluconazole-resistant strains, and resistance to echinocandins has also been rising, with one third of resistant isolates resistant to both fluconazole and echinocandins (Wiederhold, 2017).
Most recently, invasive infections due to MDR strains of Candida auris (C. auris) have been identified as an emerging threat related to healthcare. The most common C. auris resistance has been to fluconazole. Resistance has emerged during treatment with one of the medications from the echinocandin class (CDC, 2017c). More than 33% of C. auris isolates have been found to be resistant to all three major classes of antifungal agents (Kelly, 2017). C. auris has been found to persistently contaminate environmental surfaces which contributes to a high risk of nosocomial transmission (Sears & Schwartz, 2017). It is difficult to treat and eradicate, and has been reported globally. Within the United States, the highest incidences can be seen in New York, New Jersey, and Illinois. As of February 28, 2018, there have been 233 confirmed cases, and 28 probable cases in the United States (CDC, 2018a).
Due to its rapid emergence and spread, C. auris is a global health threat. Efforts to combat C. auris have proven difficult as a result of decreased ability to identify and report C. auris, as well as decreased therapeutic response to treatment. C. auris infections have an associated mortality rate of 20% to 60% (Auwaerter, 2016). Immunocompromised patients, patients on broad-spectrum antibiotics, patients with invasive devices, patients with recent surgery, and patients who have stayed in intensive care units and long-term acute care units are at the highest risk (Sears & Schwartz, 2017). Globally, C. auris cultured from infected patients has demonstrated resistance against all three main classes of antifungals (Swift, 2016). Examples include Amphotericin B, Fluconazole, and Caspofungin.
Research is being conducted and clinical drug trials are underway in the United States. One trial states that an oral antifungal agent is being tested and has compelling activity against C. auris including antibiofilm activity, growth inhibition, and inhibition of cell division (Kelly, 2017). However, there is no clear indication that this medication will be ready for public use and treatment anytime soon.
Implications for Home Care Clinicians
C. auris has the ability to colonize on patients and healthcare workers for months or longer and survive on environmental surfaces for weeks (CDC, 2018b). Patients, families, and healthcare workers should perform good hand hygiene with all patient and environmental surface contact. Healthy people are unlikely to become ill with C. auris, but can become colonized and spread to others. If a caregiver is caring for more than one ill person at home, good hand hygiene is very important to prevent spread of the infection (CDC, 2017d). All reusable medical equipment shared by more than one patient should be disinfected. Household members providing care in the home that may result in contact with contaminated material should wear disposable gloves (CDC, 2018b).
Home care clinicians must identify which of their patients are at high risk for developing antifungal-resistant infections. High-risk patients include: immunocompromised patients, including patients with long standing infections such as HIV/AIDS and those undergoing treatment for cancer; patients with impaired skin integrity, limited mobility, reoccurring or frequent bacterial infections; those patients using broad-spectrum antibiotics; patients with long-term venous access; patients with multiple comorbid conditions; and patients with extended stays in acute- and long-term-care settings (Arendrup & Patterson, 2017; CDC, 2017; Sears & Schwartz, 2017).
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