Use of Chelex-100 for the molecular diagnosis of five animal pathogens

Molecular tools have improved conventional veterinary diagnosis. Acid nucleic extraction is a key step for downstream applications. This work aimed to compare the DNA extraction method Chelex-100 resin (M1) with Whatman® cards (M2), phenol-chloroform (M3), or commercial kits (M4), and to determine the most sensitive and inexpensive one for its diagnosis of animal pathogens that, despite their economic or zoonotic relevance, receive little attention. DNA was isolated from urine, organs, semen, blood and intestinal mucous, from the bacteria Leptospira interrogans serovar Pomona Pomona (by M1 and M2), Brucella melitensis (by M1, M3 and M4), and Salmonella ser. Abortusequi (by M1 and M4), and the parasites Leishmania spp. (by M1, M3 and M4), and Eimeria spp. (by M1 and M3), respectively. The sensitivity of each method was assayed by Polymerase Chain Reaction (PCR). The M1 showed similar sensitivity for Salmonella ser. Abortusequi, Leishmania spp., and Eimeria spp., being better for L. interrogans serovar Pomona Pomona and slightly lower for B. melitensis. For the first time, a simple and economic method was successfully employed for extracting DNA from these animal pathogens, especially important in low-resource settings, contributing to the diagnosis of leptospirosis, brucellosis, leishmaniasis, and coccidiosis; as well as to the molecular epidemiology of salmonellosis in stallion from semen samples.