Isolation and Identification of Various Bacterial Species Associated with Cases of Lymphadenopathy in Dogs

Abstract

Lymphadenopathies are common ailments in companion animals, especially dogs, and can be a result of various factors like bacteria. The current study is directed towards the isolation of bacteria associated with lymphadenopathies, mainly lymphadenitis and to study its antimicrobial resistance patterns. For this, a total of 70 cases from dogs with various lymphadenopathies were studied. Dogs were examined for lymphadenomegaly, irrespective of the disease. Both the peripheral and systemic lymph nodes were considered.A clinical examination of lymph nodes followed by confirmation with an ultrasound examination was carried out. Lymph node aspirates (LNA) were collected aseptically with the guide of ultrasound examination. Obtained LNA was subjected to cytological (Leishman staining) and microscopic examination (using Gram's staining). Cytological examination revealed the presence of inflammatory cells along with bacteria, mostly cocci, some showed the presence of rods. Microscopic examination exhibited Gram-positive cocci in the peripheral lymph nodes and Gram-negative rods in the systemic lymph nodes. The LNA material was inoculated into Brain Heart Infusion agar. Bacteria like Staphylococcus spp and E. coli were identified based on cultural characteristics and confirmed with MALDI-TOF-MS. The isolated species were subjected to an antibiogram employing 12 antibiotics commonly used for the therapy of clinical infections amongst small animals in India. Azithromycin showed the highest sensitivity (100%) among all the antimicrobials. Ceftriaxone was the second most sensitive drug. Tetracycline exhibited the least sensitivity when compared to others (only 22.22%).