Molecular Detection of Bacterial Abortion Agents and Assessment of Serum MDA and GSH Levels in Aborting Small Ruminants in Siirt Province

Abortions in sheep and goat farming cause significant economic losses and a severe decline in productivity. The aim of this study was to detect the presence of Chlamydia abortus, Coxiella burnetii, Listeria spp., Listeria monocytogenes, and Campylobacter spp.—pathogens responsible for abortion cases in small ruminants—and to evaluate certain serum oxidative stress parameters. A total of 215 vaginal swab samples (sheep = 158; goats = 57) were examined using the Polymerase Chain Reaction (PCR) method. To evaluate the impact of the predominant bacterial agent, serum malondialdehyde and glutathione levels were analyzed in a focused subset (n = 140) comprising Campylobacter spp.-positive animals (n = 70) and pathogen-negative aborting controls (n = 70). PCR analysis revealed an overall positivity rate of 34.41% (n = 74), with Campylobacter spp. detected in 32.55% (70/215) and Chlamydia abortus in 1.86% (4/215) of samples, while no other targeted agents (Coxiella burnetii and Listeria spp.) were detected. In the Campylobacter spp.-positive group, serum malondialdehyde levels (32.14 ± 0.89) were significantly higher and glutathione levels (32.92 ± 3.25) were markedly lower compared to controls (9.30 ± 2.33 and 103.12 ± 1.63, respectively; p < 0.001; effect size r = 0.86), showing significant intra-species differences (p < 0.05) but no inter-species variation between infected sheep and goats (p > 0.05). In conclusion, Campylobacter spp. may play a significant role in small ruminant abortions in Siirt, which might be accompanied by cellular oxidative stress.