Isolation and detection of Corynebacterium pseudotuberculosis in the reproductive organs and associated lymph nodes of non-pregnant does experimentally inoculated through intradermal route in chronic form

Bacteriological, cytological, and molecular investigation of Corynebacterium pseudotuberculosis, mycobacteria, and other bacteria in caseous lymphadenitis and healthy lymph nodes of slaughtered sheep

Caseous lymphadenitis (CL) in sheep is a chronic contagious disease caused by Corynebacterium pseudotuberculosis, commonly characterized by abscess formation in peripheral lymph nodes and disseminated infections. Nonetheless, other microorganisms, including with zoonotic relevance, can be isolated from CL-resembling lymph nodes. Currently, mycobacteria have been reported in visceral granulomatous lesions in small ruminants, a fact that poses a public health issue, particularly in slaughtered sheep intended for human consumption. Cytology using fine needle aspiration and microbiological culturing are suitable tests for routine diagnostic, whereas present drawbacks and molecular methods have been confirmatory. Data about the occurrence of mycobacteria in both lymph nodes with aspect of CL and apparently healthy visceral nodes of sheep slaughtered for human consumption are scarce. In this study, 197 visceral lymph nodes of sheep showed lymphadenitis and 202 healthy visceral lymph nodes of slaughtered sheep intended for human consumption were submitted to conventional bacteriological diagnosis, mycobacteria culturing, and cytological evaluation. Compatible Corynebacterium isolates were subjected to multiplex PCR targeting 16S rRNA, rpoB, and pld genes to detect C. pseudotuberculosis. Based on microbiological identification, C. pseudotuberculosis (86/197; 43.7%), streptococci γ-hemolytic (17/197; 8.6%), and Trueperella pyogenes (12/197; 6.1%) were prevalent in lymph nodes with abscesses, as opposed to staphylococci (53/202; 26.2%) in apparently healthy lymph nodes. No mycobacteria were isolated. Cytology identified 49.2% (97/197) Gram-positive pleomorphic organisms (coryneform aspect). Multiplex PCR confirmed genetic material of C. pseudotuberculosis in 74.4% (64/86) of the samples with C. pseudotuberculosis isolation and 66% (64/97) samples with cytological coryneform aspect (κ = 86.78%; 95% CI = 79.87-93.68%). These findings emphasize the prevalence of C. pseudotuberculosis in abscess formation among peripheral lymph nodes of sheep. Other bacteria were also identified in lymph nodes sampled that resembling C. pseudotuberculosis-induced infections that may difficult the diagnosis. Multiplex PCR revealed a valuable assay to detect C. pseudotuberculosis, in addition to routine methods applied to CL-diagnosis. No mycobacteria were identified in lymph nodes sampled, with and without apparent lesions. Nonetheless, due to public health impacts, this pathogen should be considered as a differential diagnosis of C. pseudotuberculosis-induced infections during inspection procedures of slaughtered sheep intended for human consumption.

Clinico-pathological responses and PCR detection of Corynebacterium pseudotuberculosis and its immunogenic mycolic acid extract in the vital organs of goats

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.

Semen characteristics, extension, and cryopreservation of Rusa deer (Rusa timorensis)

AIM

The objective of this research is to report parameters for breeding soundness evaluation, semen extension, and cryopreservation in Rusa timorensis.

MATERIALS AND METHODS

Seven healthy stags were chosen for semen collection using an electroejaculator. The collections were performed twice in a breeding season between February and June 2016. Samples were collected between 2 and 3 weeks interval, collected twice for each animal. Semen was evaluated, extended, and cryopreserved using four different extenders; Andromed^®, BioXcell^®, Triladyl^®, and a modified Tris-egg yolk combined with Eurycoma longifolia Jack.

RESULTS

R. timorensis semen characteristics according to volume (ml), color, sperm concentration (10⁶/ml), general motility (%), progressive motility (%), and % morphology of normal spermatozoa are 0.86±0.18 ml, thin milky to milky, 1194.2±346.1 10⁶/ml, 82.9±2.8%, 76.1±4.8%, and 83.9±4.8%, respectively.

CONCLUSION

Semen characteristics of R. timorensis collected by electroejaculation is good allowing for cryopreservation and future artificial insemination work. The most suitable extender for Rusa deer semen is Andromed^®.

Hemogram responses in goats toward challenged with Corynebacterium pseudotuberculosis and its immunogen mycolic acids

Aim::

This study was conducted to analyze the changes in blood profile of goats inoculated with Corynebacterium pseudotuberculosis and its immunogen mycolic acid (MA) extract.

Materials and Methods::

A total of 12 clinically healthy crossbred Boer female goats were divided into three groups; A, B and C (4 goats each per group). Group A was inoculated with 2 ml sterile phosphate buffered saline via intradermal route as the negative control group whilst Group B was inoculated with 2 ml of MA extract (1 g/ml) intradermally and Group C was then inoculated with 2 ml (1×10⁹) colony forming unit of active C. pseudotuberculosis intradermally. Blood sample was collected aseptically from the jugular vein periodically for complete blood count (CBC) analysis throughout the experimental period (3 months).

Result::

A significant decrease (p<0.05) was observed in red blood cells, hemoglobin (Hb), packed cell volume, mean corpuscular volume and mean corpuscular Hb concentration in Groups B and C as compared to the control while WBCs, neutrophil, lymphocyte and basophil showed a significant increase (p<0.05) as compared to the control.

Conclusion::

The inoculation of C. pseudotuberculosis and MA resulted in a significant change in the CBC, thereby, indicating that MA has a role in caseous lymphadenitis pathogenesis.