Oral cavity is a very suitable habitat for a wide range of bacteria of which a significant proportion is facultative or strict anaerobes. In healthy individuals, specific sites of the oral cavity are colonized by specific microbial communities, and a balance of the species within the community, known as “microbial homeostasis”, is maintained. When this balance is disrupted by ecological perturbations, the biofilm composition changes leading to the initiation of local infections that may ultimately lead to tooth loss. At the onset of the infections, Gram-positive bacteria dominate the biofilm composition, but if left undisturbed, a more complex biofilm builds up where Gram-negative anaerobic and proteolytic rods become dominant.

Objective To establish a suitable method of diagnosis of visceral leishmaniasis (VL) using peripheral blood, spleen or bone marrow aspirates. Methods Peripheral blood, bone marrow and spleen aspirate samples were collected from clinically suspected VL patients (n = 26). A new PCR primer pair (MK1F/R) was designed targeting kinetoplast mini circle DNA sequences of Leishmania donovani, and Leishmania infantum, and was used to diagnose VL along with some other established primers for VL in polymerase chain reactions. Test was validated by comparing with several other diagnostic methods. Results The designed primer set showed 100% specificity and 98% sensitivity in detecting VL using blood samples, when compared with more invasive samples: bone marrow or spleen aspirates. Conclusions The newly designed primer MK1F/R could be a better alternative for PCR based diagnosis of VL using less invasive sample, peripheral blood instead of bone marrow or spleen aspirates.