Prevalence of yeast-like fungi and evaluation of several virulence factors from feral pigeons in Seoul, Korea

Abstract

Aims: Studies of pigeon‐borne yeasts have tended to focus on species, such as Cryptococcus neoformans and Candida albicans, with scant attention to feral pigeons in Korea. We studied the prevalence of yeasts from faecal samples of feral pigeons obtained in various public places in Seoul, Korea, and assessed their potential capacity as human pathogens. Methods and Results: Three hundred and six pigeon faeces samples were collected at city squares and parks in 21 localities in Seoul and Seoul Grand Park and analysed for yeast with conventional methods. Of the 306 samples, 126 (41·2%) were positive for yeast. Seventeen species of yeast were identified. The most frequent species were Candida glabrata (34·1%), Candida famata (12·7%), Cryptococcus albidus (14·3%) and Cryptococcus laurentii (7·9%). The yeast isolates were tested for virulence. Of the 116 isolates (ten isolates missing), 70·7% (n = 82) grew at 37°C. All the Cryptococcus spp. isolates possessed a capsule, 16·4% (n = 19) produced melanin, and 33·6% (n = 39) produced proteinase. Two Ca. glabrata, a Ca. famata and Ca. albicans as well as three C. neoformans, a C. laurentii and Ca. albicans isolates had three virulence factors. Accordingly, 29·3% (n = 34) isolates possessed more than two virulence factors except capsule formation. Conclusions: These results of this study indicate that feral pigeons harbour a variety of yeasts and are a reservoir of human pathogenic fungi. Significance and Impact of the Study: This study is the first time about the microflora (fungi) presents in faecal samples collected from a variety of public areas throughout Seoul, Korea.

Cryptococcus spp. isolation from excreta of pigeons (Columba livia) in and around Monterrey, Mexico

“…A similar incidence has been reported in Mexico City and in other countries such as Colombia and Perú ( Castañón Olivares et al 2000; Ruiz et al 1989; Rivas et al 1999; Quintero et al 2005; Curo et al 2005; Colom Valiente et al 1997;Castañol-Olivares and Lopez-Martinez, 1994). The finding that 50% of total Cryptococcus isolates corresponded to C. albidus is not surprising given the fact that 14% and 12% of pigeon excreta isolates in Seoul and Brazil correspond to this species and now it is considered an underestimated pathogen by several researchers ( Jang et al 2011; Soares et al 2005). Comparison of 18S RNA sequence against other reported sequences shows that the isolates form clades with their corresponding species according to the microbiological test results.…”

Diversity and abundance of human‐pathogenic fungi associated with pigeon faeces in urban environments

“…Although culture-independent, high-throughput sequencing approaches are extremely sensitive for detection of rare or uncultur- Guz, 2011;Lo Cascio et al, 2007;Mancianti, Nardoni, & Ceccherelli, 2002;Mendes et al, 2014;Wojcik, Kurnatowski, & Blaszkowska, 2013), have been isolated from pigeon faeces in only two studies, both conducted in Seoul (Chae et al, 2012;Jang et al, 2011). Whether this represents simple sampling bias or specialization of these species in Seoul requires further investigation.…”

“…For example, Ca. glabrata was isolated from pigeons only between April and July (Jang et al, 2011;Kocan & Hasenclever, 1974).…”

“…Seoul is an ideal place to evaluate the relationship between pigeons and potentially pathogenic fungal diversity because it has a large, dense human population (>24 million in the greater metropolitan area: the fourth largest in the world) and, as is true with most other major cities in the world, pigeon populations have dramatically increased in tandem with the increase in human urbanization (Moller et al, 2012). In addition, previous culture-based studies in the Seoul area have identified several potentially pathogenic fungi in pigeon faeces (Chae et al, 2012;Chee & Lee, 2005;Jang et al, 2011).…”

Comparison of Stool Microscopy between Young and Elderly Adults without Diarrhea in Rural Bangladesh

“…There is also a reduction in gastric juice secretion, especially hydrochloric acid which can facilitate small bowel bacterial overgrowth leading to malabsoption [6]. These age related changes may manifest as an excessive presence of opportunistic pathogens, such as yeast, and the presence of undigested food particles, such as vegetable cells, in the stool [7][8][9][10]. Therefore, understanding age related findings on stool microscopy may have public health importance.…”