Diversity, Virulence Factors, and Antifungal Susceptibility Patterns of Pathogenic and Opportunistic Yeast Species in Rock Pigeon (Columba livia) Fecal Droppings in Western Saudi Arabia

Abstract

Bird fecal matter is considered a potential source of pathogenic microbes such as yeast species that contaminate the environment. Therefore, it needs to be scrutinized to assess potential environmental health risks. The aim of this study was to investigate the diversity of the yeasts in pigeon fecal droppings, their antifungal susceptibility patterns, and virulence factors. We used culturing techniques to detect the yeasts in pigeon fecal droppings. The isolates were then characterized based on colony morphologies, microscopic examinations, and biochemical reactions. The molecular identification of all yeast isolates was performed by sequencing of the amplified ITS gene. Genes encoding virulence factors CAP1, CAP59, and PLB were also detected. Antifungal susceptibility patterns were examined by the disk diffusion method. A total of 46 yeast-like isolates were recovered, and they belonged to nine different genera, namely, Cryptococcus, Saccharomyces, Rhodotorula, Candida, Meyerozyma, Cyberlindnera, Rhodosporidium, Millerozyma, and Lodderomyces. The prevalence of two genera Cryptococcus and Rhodotorula was high. None of the yeast isolates exhibited any resistance to the antifungal drugs tested; however, all pathogenic Cryptococcus species were positive for virulence determinants like urease activity, growth at 37°C, melanin production, the PLB and CAP genes. This is the first report on the molecular diversity of yeast species, particularly, Cryptococcus species and their virulence attributes in pigeon fecal droppings in Saudi Arabia.

Safety Evaluation of Yeasts With Probiotic Potential

“…These results agree with those reported by Abulreesh et al (43). Maciel et al (44) also observed how different non-Saccharomyces yeasts were susceptible to antifungals, including those of the Pichia genus which was susceptible to Fluconazole.…”

Identification of Pathogenic and Opportunistic Yeasts in Pigeon Excreta by MALDI-TOF Mass Spectrometry and Their Prevalence in Chon Buri Province, Thailand

“…Pigeon droppings are becoming a significant environmental issue, along with the increasing population of pigeons. Further, pigeon excreta are among serious public health concerns because they are considered reservoirs and carriers of opportunistic and pathogenic microorganisms, such as fungi, bacteria, and viruses [ 1 , 2 ]. Numerous previous reports emphasized the extent of bacterial colonization in pigeon excreta.…”

“…In the city of Moscow, Candida albicans was found in high abundance and frequency, as well as other opportunistic yeasts, including Diutina catenulate, Millerozyma farinosa , Pichia kudriavzevii , and Trichosporon asahii [ 6 ]. In western Saudi Arabia, of a total of 46 yeast-like isolates molecularly identified in pigeon droppings, Cryptococcus neoformans was the most prevalent yeast species (11 isolates), followed by Cryptococcus albidus (5 isolates), Saccharomyces cerevisiae (5 isolates), and Rhodotorula mucilaginosa (5 isolates) [ 1 ]. In Thailand, most studies have focused on the isolation and identification of Cryptococcus spp., especially C. neoformans [ 7 , 8 ].…”

Search for Cryptococcus neoformans/gattii Complexes and Related Genera (Filobasidium, Holtermanniella, Naganishia, Papiliotrema, Solicoccozyma, Vishniacozyma) spp. Biotope: Two Years Surveillance of Wild Avian Fauna in Southern France

“…While originally thought to be strictly plant-borne, C. gattii s.l. strains have also been found in bat guano [ 24 ], insect nests, and insect frass [ 25 , 26 ] bird excreta, [ 27 , 28 ] and in dens/burrows of at least one mammal, the African hyrax [ 29 ]. Isolates were also obtained from a wide range of animals, such as gray squirrels [ 30 ], porpoises [ 31 ], and pets such as dogs and cats, during the 1999 Vancouver outbreak.…”