European Journal of Biomedical and Pharmaceutical Sciences

Candida Lusitaniae, ISOLATION AND CLINICAL IMPORTANCE IN MEXICO DURING THE FINAL STRECH OF THE COVID-19 PANDEMIC

Cudberto Contreras Pérez, Elizabeth González Durán, Patricia Gutiérrez García, Claudia Ríos-Rosas, José D. Méndez

ABSTRACT

During the COVID-19 pandemic, opportunistic yeast infections of the genus Candida increased. During the final phase of the pandemic in Mexico, nine isolates of Candida lusitaniae were identified. The cases came from nine hospitalized patients: five neonates, one adolescent, and three adults. From August 2025 to July 2026, no additional cases were reported. The identification of Candida lusitaniae by phenotypic tests proved rapid, reliable, and timely. The use of CHROMagar™ Orientation represents an important differentiating factor compared to other species of the genus Candida, particularly those grouped in the CTG clade, with which erroneous identifications occurred in the past. Regarding primary or acquired resistance in this species, the results in the literature have been controversial. Of the 11 Candida lusitaniae isolates, only one was resistant to voriconazole, amphotericin B, caspofungin, and micafungin, but sensitive to 5-fluorocytosine. The resistant strain was isolated from a 16-year-old patient diagnosed with pneumonia, from the state of Michoacán, Mexico, which maintains reliable coverage of systemic candidiasis cases in that region. Currently, Candida lusitaniae is considered a species sensu stricto. Sequencing of PCR products from the ITS1 region reveals significant genetic variability among clinical isolates of Candida lusitaniae. Phylogenetic analysis of the studied isolates clearly distinguishes three subgroups: two stable subgroups and one subgroup with intraspecific variability. No relationship was found between patients, medical institutions, or geographic region. The results obtained are related to the low transmissibility and dispersion of this species in medical facilities. The prevention of healthcare-associated infections (HAIs) requires reliable, timely, and comprehensive results between the medical field and the clinical laboratory. The rapid and accurate identification of Candida lusitaniae will contribute to taking more effective measures for its control.

Keywords: Candida lusitaniae, Phenotypic tests, Fungigram, PCR/Sequencing.