The presence of yeasts and bacteria in free-living amoebae isolated from COVID-19 patients: concern for secondary infections

This study aimed to investigate the presence of SARS-CoV-2, yeasts, and bacteria in isolated free-living amoeba (FLA) from COVID-19 patients. Nasopharyngeal swabs (<i>n</i> = 60) were obtained from COVID-19 patients. After cultivation, morphological characterization, and RNA/DNA extraction, the presence of selected microorganisms was investigated. From 60 COVID-19 samples, 18 (30%) were positive for FLA. <i>Acanthamoeba</i> sp. <i>Naegleria australiensis</i>, <i>Tetramitus</i> sp. and <i>Vermamoeba vermiformis</i> were characterized in 12 (80%), 1 (6.66%), 2 (13.33%), and 7 (38.88%) of samples, respectively. SARS-CoV-2 RNA was not detected in FLA. <i>Candida albicans</i>, <i>C. tropicalis</i>, and <i>C. parapsilosis</i> were detected in (11/18; 61.11%), (3/18; 16.67%), and (3/18; 16.67%) of samples, respectively. <i>Geotrichum candidum</i> was detected in 10/18 (55.55%) of samples. <i>Streptococcus</i> spp. and <i>Staphylococcus</i> spp. were identified in 16/18 (88.88%) and 3/18 (16.67%), respectively. The presence of yeasts and bacteria signifies the possible role of FLA in distribution of secondary infections in susceptible patients.