The occurrence of Listeria monocytogenes in goats, farm environment and invertebrates

Abstract

ABSTRACT The occurrence of Listeria monocytogenes at seven different organized goat farms and its environment was studied. A total of 482 samples from goats having a history of abortion and apparently healthy animals (n = 380), farm environment (n = 51) and invertebrates (n = 51; flies and ticks) were collected. Besides, serum samples were collected from goats having a history of abortion (n = 95) and apparently healthy animals (n= 98). The isolation of the pathogen was performed with two-step enrichment followed by selective plating. Listeria spp. were isolated from 26 (5.39%) samples. Of these, 12 (3.15%) isolates were confirmed as L. monocytogenes recovered from goats, 1 isolate from farm environment (soil) and 2 isolates from invertebrates (fly and tick). Out of seven organized farms screened, three showed the occurrence of L. monocytogenes in the animals having a history of abortion, associated farm environment and invertebrates. PCR-based serotyping of L. monocytogenes revealed 14 isolates to be of serogroup 4b, 4d, 4e and one of serogroup 1/2a, 1/2c, 3a, 3c. Seropositivity using indirect ELISA was observed in 11 (11.58%) goats having a history of abortion and 3(3.06%) inapparently healthy goats. This study highlighted the role of vectors in listeric infections. Abbreviations:UVM - University of Vermont Medium; PALCAM - Polymyxin Acriflavin Lithium-chloride Ceftazidime Esculin Mannitol; LLO- Listeriolysin O