日本語AIでPubMedを検索
ヤギの重要臓器におけるCorynebacterium pseudotuberculosisとその免疫原性ミコール酸抽出物の臨床病理学的反応とPCR検出
Clinico-pathological responses and PCR detection of Corynebacterium pseudotuberculosis and its immunogenic mycolic acid extract in the vital organs of goats.
PMID: 31325572 DOI: 10.1016/j.micpath.2019.103628.
抄録
Caseous lymphadenitis is an infectious disease of almost all animals, particularly small ruminants that are caused by Corynebacterium pseudotuberculosis. The organism causes the formation of suppurative abscesses in superficial and visceral lymph nodes and in visceral organs. This current study was designed to elucidate the clinicopathological responses and PCR detection of the aetiological agent in the vital organs of goats challenged with C. pseudotuberculosis and its immunogenic mycolic acid extract. A total of twelve clinically healthy crossbred Boer female goats were divided into three groups: A, B, and C (four goats per group). Group A was inoculated intradermally with 2 ml of sterile phosphate buffered saline (PBS) pH 7 as a control group. Group B was inoculated intradermally with 2 ml of mycolic acid extract (1 g/ml), while group C was inoculated intradermally with 2 ml of 10⁹ colony-forming unit (cfu) of live C. pseudotuberculosis. The experimental animals were observed for clinical responses for 90 days post-inoculation and the clinical signs were scored according to the severity. The clinical signs observed in this study were temperature, heart rate, respiratory rate, rumen motility, enlargement of lymph nodes, and body condition score. The experimental animals were euthanised and tissue samples from different anatomical regions of the vital organs were collected in 10% buffered formalin, processed, sectioned, and stained with H&E. Results of both C. pseudotuberculosis and mycolic acid treated groups indicated a significant difference (p < 0.05) in body temperature. Group C showed a significant increase in temperature (p < 0.05) at week 1 (39.59 ± 0.29 °C), week 2 (39.67 ± 0.27 °C) and week 3 (40.22 ± 0.15 °C). Whereas group B showed a significant increase in temperature (p < 0.05) only at week 1 (39.36 ± 0.14 °C). Heart rate in group C showed a significant increase between week 1 (93.35 ± 0.42 bpm) and week 11 (86.52 ± 1.32 bpm), and the mean heart rate of group B showed a significant increase (p < 0.05) between week 1 (89.90 ± 0.60 bpm) and week 9 (86.90 ± 0.99 bpm). Group C showed a significant increase of respiratory rate (p < 0.05) at week 1 (36.85 ± 0.14 bpm), week 2 (36.90 ± 0.62), week 3 (30.80 ± 1.97 bpm), and week 4 (34.85 ± 1.19 bpm). The mean of the respiratory rate of group B only increased at week 1 (32.98 ± 1.30 bpm) and week 2 (31.87 ± 0.48 bpm). Both groups C & B showed significant decreases in rumen motility and body condition score as compared to the control. The histopathological changes were significant in group C, this was shown by mild to severe haemorrhage, congestion, degeneration and necrosis, oedema, infiltration with inflammatory cells mainly lymphocytes and macrophages, while group B was less affected and showed mild to moderate haemorrhage, congestion, degeneration and necrosis, infiltration of inflammatory cells and oedema as compared to the control group. This study concluded that C. pseudotuberculosis caused typical CLA disease with a short incubation period in the experiment. While the mycolic acid extracted from C. pseudotuberculosis caused mild clinical signs, no abscess formation, and negative PCR result. Moreover, evidence of mild to moderate histopathological changes in vital organs was also observed.
Copyright © 2019 Elsevier Ltd. All rights reserved.