HEMATOLOGICAL PARAMETERS AFTER INFECTION OF GOATS WITH THE RHODOCOCCUS EQUI PVAPA PLASMID

This study evaluated the temporal dynamics of hematological parameters in 2–3-monthold Saanen goats after inoculation with virulent pVapA-positive Rhodococcus equi strains. Hemoglobin (Hb), red blood cells (RBC), white blood cells (WBC), hematocrit (HCT), MCV, MCH, MCHC, and RDW were analyzed over a 0–65-day period in comparison with the control group. Overall, no persistent statistically significant differences were detected between the groups at the main time points. A decrease in Hb was observed only in the VapA-108 group on day 65 compared with the control (p=0.033); however, the small number of animals in each group (n=3) requires cautious interpretation of this result. The wide 95% confidence intervals and high coefficients of variation indicated marked individual variability. The obtained data suggest that, in the goat model, pVapA-positive R. equi strains induced a weak and variable response rather than pronounced and persistent systemic hematological alterations.

1. Jain S., Bloom B.R., Hondalus M.K. Deletion of vapA encoding Virulence Associated Protein A attenuates the intracellular actinomycete Rhodococcus equi // Molecular Microbiology. – 2003. – Vol. 50[1]. – P. 115–128. doi:10.1046/j.1365-2958.2003.03689.x.

2. MacArthur I., Anastasi E., Alvarez S. et al. Comparative genomics of Rhodococcus equi virulence plasmids and host adaptation // (review, PMC). – 2017.

3. Salazar‑Rodríguez D., Azevedo V., Calderón‑Espinoza M.L. et al. Virulence Plasmids of Rhodococcus equi Isolates From Humans and Animals // Frontiers in Veterinary Science. – 2021. – 8:628239. doi:10.3389/fvets.2021.628239.

4. Rofe A.P., Davis L.J., Whittingham J.L. et al. The Rhodococcus equi virulence protein VapA disrupts endolysosome function and stimulates lysosome biogenesis // MicrobiologyOpen. – 2017. doi:10.1002/mbo3.416.

5. Miranda‑CasoLuengo R., Meijer W.G. The N‑terminal domain is required for cell surface localisation of VapA in Rhodococcus equi // PLOS ONE. – 2024. doi:10.1371/journal.pone.0298900.

6. Okoko T., Rao L., Proulx‑Millimaki R. et al. Structural characterisation of the virulence‑associated plasmid of Rhodococcus equi // Veterinary Microbiology. – 2015.

7. Takai S. et al. Virulence plasmids in clinical isolates of Rhodococcus equi from sick foals // Letters in Applied Microbiology. – 2022.

8. Yerlikaya Z., Miranda‑CasoLuengo R., Meijer W.G. Clade‑1 Vap virulence proteins of Rhodococcus equi and their functional roles // (review, PMC). – 2025.

9. Weronika Kruczkowska, Mateusz Kciuk, Zbigniew Pasieka, Karol Kłosiński, Elżbieta Płuciennik, Jacob Elmer, Klaudia Waszczykowska, Damian Kołat & Żaneta Kałuzińska-Kołat. The artificial oxygen carrier erythrocruorin-characteristics and potential significance in medicine. Journal of Molecular Medicine. Volume 101, pages 961–972, (2023). doi.org/10.1007/s00109-023-02350-3.

10. Chng, K.Z., Ng, Y.C., Namgung, B. et al. Assessment of transient changes in oxygen diffusion of single red blood cells using a microfluidic analytical platform. Commun Biol 4, 271 (2021). https://doi.org/10.1038/s42003-021-01793-z.

11. Wearing, O.H., Ivy, C.M., Gutiérrez-Pinto, N. et al. The adaptive benefit of evolved increases in hemoglobin-O2 affinity is contingent on tissue O2 diffusing capacity in high-altitude deer mice. BMC Biol 19, 128 (2021). https://doi.org/10.1186/s12915-021-01059-4.

12. Baskurt OK, Meiselman HJ. Blood rheology and hemodynamics. Semin Thromb Hemost. 2003;29(5):435–450. DOI: 10.1055/s-2003-44551

13. Jensen FB. The dual roles of red blood cells in tissue oxygen delivery: oxygen carriers and regulators of local blood flow. J Exp Biol. 2009;212(Pt 21):3387-3393. DOI: 10.1242/jeb.023697

14. Perutz MF. Mechanisms of cooperativity and allosteric regulation in proteins. Q Rev Biophys. 1989;22(2):139-237. DOI: 10.1017/s0033583500003826.

15. Zimmerman D, DiIusto M, Dienes J, Abdulmalik O, Elmer JJ. Direct comparison of oligochaete erythrocruorins as potential blood substitutes. Bioeng Transl Med. 2017 Jul 19;2(2):212-221. doi: 10.1002/btm2.10067.

16. Zhu K, Wang L, Xiao Y, Zhang X, You G, Chen Y, Wang Q, Zhao L, Zhou H, Chen G. Nanomaterial-related hemoglobin-based oxygen carriers, with emphasis on liposome and nano-capsules, for biomedical applications: current status and future perspectives. J Nanobiotechnology. 2024 Jun 16;22(1):336. doi: 10.1186/s12951-024-02606-1.

17. Mohanto N, Park YJ, Jee JP. Current perspectives of artificial oxygen carriers as red blood cell substitutes: a review of old to cutting-edge technologies using in vitro and in vivo assessments. J Pharm Investig. 2023;53:153–90. doi: 10.1007/s40005-022-00590-y.

18. Cao M, Wang G, He H, Yue R, Zhao Y, Pan L, Huang W, Guo Y, Yin T, Ma L et al (2021) Hemoglobin-based oxygen carriers: potential applications in solid organ preservation. Front Pharmacol 12:760215. 10.3389/fphar.2021.760215.

19. Drvenica IT, Stancic AZ, Maslovaric IS, Trivanovic DI, Ilic VL (2022) Extracellular hemoglobin: modulation of cellular functions and pathophysiological effects. Biomolecules 12. 10.3390/biom12111708.