Genetic diversity of Cryptococcus Neoformans isolates from pigeon (Columba Livia) droppings in Bangkok

Abstract

This study was designed to differentiate C. neoformans isolates from pigeon droppings from Bangkok area by Random Amplified Polymorphic DNA (RAPD) using M13 as a single primer. Out of the 51 districts, the samples were collected from twenty one random districts during the periods of June 2003 to April 2004. Sixteen samples from each district were included. The results showed that C. neoformans were presented in 30 samples, collected from 10 districts out of 21 randomized districts. Samphantawong district was the predominant area, showing the highest detectable percentage of C. neoformans, that was 13 of 16 samples (81.3%), followed by 3 of 16 samples (18.8%) from Min Buri and Thon Buri. 2 of 16 samples (12.5%) from Pasri Jareon, Ladpraw, Yannawa, and Bang Plad, and only 1 of 16 samples (6.3%) was found in Phayathai, Pranakorn, and Pomprab Satrupai, respectively. Randomized 53 isolates were recovered from 30 samples. Canavanine glycine bromothymol blue was used to investigate the variety level. It was shown that 52 isolates (98%) were C. neoformans var grubii (serotype A/D, AD) and 1 isolate (2%) was C. neoformans var gattii (serotype B or C). From RAPD analysis, 50/52 (94.3%) was C. neoformans var grubii, molecular type VNI, serotype A ,2/52 (3.77%) was classified as was C. neoformans var grubii, molecular type VNII, serotype A, and only one was C. neoformans var gattii (serotype B or C). The different of band numbers in each profile can discriminate the VNI type into 7 subtypes, VNI.1, VNI.2, VNI.3, VNI.4, VNI.5, VNI.6, and VNI.7 and the VNII type into 2 subtypes. In conclusion, C. neoformans isolates from pigeon droppings in Bangkok showed various genetic diversity.