Classification of Giardia intestinalis isolates by multiple polymerase chain reaction (multiplex)

Abstract

Agarose gel electrophoresis of gdh gene fragments, amplified by Multiplex, was used to classify the assemblage of 24 Giardia isolates obtained from axenic cultures, children's stools, and feces of puppies from different dog breeds. Isolates were compared with seven reference strains of Giardia intestinalis. The results showed that 22/24 isolates (91%) belonged to assemblage A and could be further subclassified as assemblage A1 (18/22, 81%) and assemblage A2 (4/22, 19%). One sample revealed a mixture of A1/A2 genotypes, and another was assemblage G, indicating mixed infections by different strains in the same host, and an association with the assemblage reported in animals. The procedure described is useful to determine the Giardia genotype that parasitizes each host to conduct epidemiological studies assessing the close association between human- and animal-infecting strains and to monitor the adaptability of animal strains to humans.

Giardia duodenalis genotypes among schoolchildren and their families and pets in urban and rural areas of Sinaloa, Mexico

“…Although G. duodenalis isolated from dogs typically belong to C or D genotypes, A and B also have been identified in the regions with high endemic areas of genotypes A and B, such as in Argentina [21], Brazil [42], Peru [48], and Mexico [18,[38][39][40]. Sharing of the same G. duodenalis genotype between dogs and their owners has been reported [49].…”

“…Various factors, such as biological, geographic, human activities, and wildlife of certain region, among others, have been proposed for higher prevalence of one genotype over another [21,42]. In Mexico, published studies about human giardiasis are lacking clinical data and, as mentioned above, this pathology is mainly associated with genotype A (AI, AII or AI-AII) [9,18,[37][38][39][40]. Only one report showed six genotype B cases in southeastern Mexico [12].…”

“…However, Giardia genotypes in 181 individuals were recently studied in Colombia, with genotype B (90%), A (3%), and mixed infections A+B (7%) detected [29]. Although genotype B and mixed A and B infections have been reported in many countries of the world [30][31][32][33][34][35][36], previous studies in Mexico reported only the presence of genotype A (AI and AII) [9,18,[37][38][39][40] until the recent discovery of genotype B in humans in southwestern Mexico [12].…”

Intestinal parasites and genotyping of Giardia duodenalis in children: first report of genotype B in isolates from human clinical samples in Mexico

“…Despite the high prevalence of gi- rdiasis, molecular epidemiology studies of Giardia in Mexico are still scarce. Previous studies performed in Mexico with human isolates have reported only the presence of assemblage A (sub-assemblages A-I and A-II) ( Ponce-Macotela et al 2002 , Cedillo-Rivera et al 2003 , Eligio-García et al 2005 , 2008a , b , Lalle et al 2005 ). However, these studies were all performed with samples from the central and north of Mexico.…”

“…Lalle et al (2005) reported that all isolates tested belonged to genotype A. Eligio-García et al (2008a , b ) reported the presence of genotypes A-I, A-II and a mixture of both from samples of clinical isolates. From these studies, 110 isolates from humans belonged to genotype A (64 from axenic isolates and 46 from stool samples) and none to genotype B, an unusual result considering that genotype B has been reported in most series of cases worldwide.…”