Evaluation of the Efficiency of Detection of Bacterial DNA in Milk and Tissue Samples from Cattle, Sheep, and Goats by Conventional and Nested PCR Targeting <i>COM1</i> , <i>SOD</i> and Transposase IS <i>1111</i> Genes of <i>Coxiella burnetii</i> Gen

Abstract Q fever is a worldwide zoonosis, caused by Coxiella burnetii , an obligate intracellular bacterium that affects both humans and animals. The serious consequences on human health and the economic losses it causes, require the use of rapid, accurate, and sensitive diagnostic methods for its detection. PCR is the most widely used method for the molecular detection of Coxiella burnetii . Considering available information on the different sensitivity of PCR assays according to the selected genetic targets to be amplified, the present study aimed to compare the effectiveness of conventional and nested PCRs performed with primers Trans 1/2 , OMP 1-4 , and CB1/CB2 for the detection of Coxiella burnetii genome in samples, obtained from cattle, sheep and goats. Thirty archival DNAs, extracted from placentae, vaginal swabs, bulk tank milk samples, and cheese were tested. The highest level of detection was found when samples were tested with nested PCR with primers OMP 1-4 , targeting the Com1 gene (96.3%), and to a lesser extent with conventional PCR (56.7% positivity), performed with primers Trans 1/2 , encompassing a part of the IS 1111 insertion sequence. A correlation was found between the detection efficiency of some primers and the type and origin of the samples. The results show that the sensitivity of the various PCR protocols for the detection of Coxiella burnetii could vary, thus the results obtained with one genetic marker should be interpreted with caution.