Study: Misdiagnosed Fungal Infections Contribute to Antibiotic Resistance

A recent paper cited the lack of routine diagnostic testing for fungal infections in patients as a contributing factor to antimicrobial resistance.

Researchers, led by David Denning of the Global Action Fund for Fungal Infections, found 4 common clinical situations that illustrate the excessive use of antibacterial and antifungal drugs and the need for fungal testing: inaccurate diagnosis of fungal sepsis, failure to diagnosis chronic pulmonary Aspergillosis, misdiagnosis of fungal asthma, and overtreatment and undertreatment of Pneumocystis pneumonia (PCP) in HIV-positive patients.
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“Hospitalized patients, especially those in intensive care units, are often inappropriately placed on broad-spectrum antibiotic drugs because fungal diseases involving Candida spp. are not routinely diagnosed,” the researchers stated.

They found incidences of bloodstream infections with Candida spp. to be 1.2 to 26 cases per 100,000 people, with the highest rates in the middle and high income countries, including the United States. The number of cases and mortality increased in developing countries. The misdiagnosis resulted in more prescribed antibiotic treatment for patients. The researchers recommend 1,3 β-D-glucan assay, the candida albicans germ tube antibody test, and nonculture-based molecular assay to determine if a patient was colonized with Candida. Likewise, researchers found that antimicrobial stewardship programs that use diagnostics to rule out invasive candidiasis have successfully shortened antifungal therapy without worsening outcomes in patients.

Chronic pulmonary aspergillosis is often underdiagnosed in patients with smear-negative tuberculosis (TB), according to the researchers. Aspergillosis mimics the symptoms of TB and is often mistaken for antibiotic resistant TB when treatment fails. According to their findings, Aspergillosis may be more common and the misdiagnosis could result in severe infections and more hospitalizations. The researchers recommend the use of Aspergillosis anti-body testing as a part of TB control programs, and that all patients with TB symptoms should be screened.

In addition, the researchers recommend fungal-specific IgE testing or skin-prick testing to detect if patients with asthma or chronic obstructive pulmonary disease (COPD) are colonized by Aspergillus spp. According to researchers, “failure to properly diagnose and treat patients with asthma and COPD who are colonized with Aspergillus spp. continues to increase the inappropriate use of antibiotic drugs and corticosteroids among these patients. Recognition of fungal infection and allergy and treatment with directed antifungal therapy would greatly reduce exacerbations, medical consultations, and hospital admissions.” Their findings indicate that improper treatment of fungal asthma and COPD increases the mortality rate of patients, as well.

Researchers estimated that hundreds of thousands of patients with HIV may be given unnecessary antibiotic treatment for PCP infections. “Early detection and diagnosis of PCP can help prevent unnecessary hospitalizations, reduce adverse events and healthcare costs,” the researchers stated. They recommend 1,3 β-D-glucan testing, bronchoscopy and microscope examination of bronchoalveolar lavage fluids to detect PCP.

“The lack of availability and underuse of nonculture fungal diagnostics results in overprescribing, prescription of unduly long courses of antibacterial agents, and excess empirical use of antifungal agents and leaves many millions of patients with undiagnosed fungal infections,” the researchers concluded. Likewise, the implementation of fungal diagnostics as a part of health care would benefit drug usage and support stewardship programs.

—Melissa Weiss

Reference:

Denning DW, Perlin DS, Muldoon EG, et al. Delivering on antimicrobial resistance agenda not possible without improving fungal diagnostic capabilities [published online before print December 20, 2016]. Emerging Infectious Diseases. doi: 10.3201/eid2302.152042.