FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Journal of veterinary internal medicine2022; 36(3); 1139-1145; doi: 10.1111/jvim.16409

Association of pneumonia with concentrations of virulent Rhodococcus equi in fecal swabs of foals before and after intrabronchial infection with virulent R. equi.

Abstract: Intragastric administration of virulent Rhodococcus equi protects foals against subsequent experimental intrabronchial (IB) infection, but it is unknown whether R. equi naturally ingested by foals contributes to their susceptibility to pneumonia. Objective: Fecal concentration of virulent R. equi before IB infection with R. equi is positively associated with protection from pneumonia in foals. Methods: Twenty-one university-owned foals. Methods: Samples were collected from experimental studies. Five foals were gavaged with live, virulent R. equi (LVRE) at age 2 and 4 days; the remaining 16 foals were not gavaged with LVRE (controls). Fecal swabs were collected from foals at ages 28 days, immediately before IB infection. Foals were monitored for clinical signs of pneumonia, and fecal swabs were collected approximately 2 weeks after IB infection. Swabs were tested by quantitative PCR for concentration of virulent R. equi (ie, copy numbers of the virulence-associated protein A gene [vapA] per 100 ng fecal DNA). Results: Fecal concentrations of virulent R. equi (vapA) before IB infection were significantly (P < .05) lower in control foals (25 copies/100 ng DNA [95% CI, 5 to 118 copies/100 ng DNA) that developed pneumonia (n = 8) than in healthy control foals (n = 8; 280 copies/100 ng DNA; 95% CI, 30 to 2552 copies/100 ng DNA) or those gavaged with LVRE (707 copies/100 ng DNA, 95% CI, 54 to 9207 copies/100 ng DNA). Conclusions: Greater natural ingestion of LVRE might contribute to protection against pneumonia among foals.
© 2022 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.
Get Full Text
Publication Date: 2022-03-24 PubMed ID: 35322902PubMed Central: PMC9151490DOI: 10.1111/jvim.16409Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research investigates the connection between the occurrence of pneumonia in foals (young horses) and their exposure to the bacterium Rhodococcus equi. The study suggests that having a higher amount of the bacteria in the foal’s feces before an induced infection could lower their risk of getting pneumonia.

Approach

  • The researchers conducted an experiment with 21 foals owned by a university. These foals were divided into two groups: a test group that was given a strain of the Rhodococcus equi bacterium via a process called gavage (a tube is used to feed directly into an animal’s stomach), and a control group that was not given the bacterium.
  • Samples were collected from the foals at age 28 days, immediately before an induced infection within the foal’s bronchus (a major air passage to the lungs).
  • The researchers kept track of the health of the foals and collected feces samples about two weeks after the infection was induced.

Methodology

  • A method called quantitative PCR was used to identify and measure the amount of Rhodococcus equi present in the feces samples. They specifically looked for and counted the copies of the virulence-associated protein A gene (vapA), which is an indicator of the presence of virulent Rhodococcus equi.

Results

  • The researchers found that the amount of virulent Rhodococcus equi in the feces of control foals that later developed pneumonia was significantly lower than the amount found in healthy foals or those fed Rhodococcus equi via gavage. This was the case both before the induced infection and after.

Conclusions

  • The researchers concluded that higher natural ingestion of virulent Rhodococcus equi could play a role in protecting foals against pneumonia. The method by which the bacteria provides the protection needs further research.

Cite This Article

APA
Cohen ND, Kahn SK, Bordin AI, Gonzales GM, da Silveira BP, Bray JM, Legere RM, Ramirez-Cortez SC. (2022). Association of pneumonia with concentrations of virulent Rhodococcus equi in fecal swabs of foals before and after intrabronchial infection with virulent R. equi. J Vet Intern Med, 36(3), 1139-1145. https://doi.org/10.1111/jvim.16409

Publication

Journal of veterinary internal medicine
ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 36
Issue: 3
Pages: 1139-1145

Researcher Affiliations

Cohen, Noah D
  • Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Kahn, Susanne K
  • Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Bordin, Angela I
  • Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Gonzales, Giana M
  • Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
da Silveira, Bibiana Petri
  • Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Bray, Jocelyne M
  • Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Legere, Rebecca M
  • Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
Ramirez-Cortez, Sophia C
  • Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.

MeSH Terms

  • Actinomycetales Infections / veterinary
  • Animals
  • Horse Diseases / diagnosis
  • Horses
  • Humans
  • Pneumonia / veterinary
  • Rhodococcus equi

Grant Funding

  • Boehringer-Ingelheim Animal Health Inc
  • Link Equine Research Endowment

Conflict of Interest Statement

Authors declare no conflict of interest.

References

This article includes 36 references
  1. Prescott JF. Rhodococcus equi: an animal and human pathogen.. Clin Microbiol Rev 1991 Jan;4(1):20-34.
    pmc: PMC358176pubmed: 2004346doi: 10.1128/cmr.4.1.20google scholar: lookup
  2. Takai S. Epidemiology of Rhodococcus equi infections: a review.. Vet Microbiol 1997 Jun 16;56(3-4):167-76.
    pubmed: 9226831doi: 10.1016/s0378-1135(97)00085-0google scholar: lookup
  3. Meijer WG, Prescott JF. Rhodococcus equi.. Vet Res 2004 Jul-Aug;35(4):383-96.
    pubmed: 15236672doi: 10.1051/vetres:2004024google scholar: lookup
  4. Giguère S, Hondalus MK, Yager JA, Darrah P, Mosser DM, Prescott JF. Role of the 85-kilobase plasmid and plasmid-encoded virulence-associated protein A in intracellular survival and virulence of Rhodococcus equi.. Infect Immun 1999 Jul;67(7):3548-57.
    pmc: PMC116543pubmed: 10377138doi: 10.1128/iai.67.7.3548-3557.1999google scholar: lookup
  5. Barton MD, Hughes KL. Ecology of Rhodococcus equi.. Vet Microbiol 1984 Feb;9(1):65-76.
    pubmed: 6719819doi: 10.1016/0378-1135(84)90079-8google scholar: lookup
  6. Morton AC, Begg AP, Anderson GA, Takai S, Lämmler C, Browning GF. Epidemiology of Rhodococcus equi strains on Thoroughbred horse farms.. Appl Environ Microbiol 2001 May;67(5):2167-75.
    pmc: PMC92851pubmed: 11319096doi: 10.1128/aem.67.5.2167-2175.2001google scholar: lookup
  7. Muscatello G, Anderson GA, Gilkerson JR, Browning GF. Associations between the ecology of virulent Rhodococcus equi and the epidemiology of R. equi pneumonia on Australian thoroughbred farms.. Appl Environ Microbiol 2006 Sep;72(9):6152-60.
    pmc: PMC1563629pubmed: 16957241doi: 10.1128/aem.00495-06google scholar: lookup
  8. Cohen ND, Carter CN, Scott HM, Chaffin MK, Smith JL, Grimm MB, Kuskie KR, Takai S, Martens RJ. Association of soil concentrations of Rhodococcus equi and incidence of pneumonia attributable to Rhodococcus equi in foals on farms in central Kentucky.. Am J Vet Res 2008 Mar;69(3):385-95.
    pubmed: 18312138doi: 10.2460/ajvr.69.3.385google scholar: lookup
  9. Muscatello G, Gerbaud S, Kennedy C, Gilkerson JR, Buckley T, Klay M, Leadon DP, Browning GF. Comparison of concentrations of Rhodococcus equi and virulent R. equi in air of stables and paddocks on horse breeding farms in a temperate climate.. Equine Vet J 2006 May;38(3):263-5.
    pubmed: 16706283doi: 10.2746/042516406776866480google scholar: lookup
  10. Cohen ND, Chaffin MK, Kuskie KR, Syndergaard MK, Blodgett GP, Takai S. Association of perinatal exposure to airborne Rhodococcus equi with risk of pneumonia caused by R equi in foals.. Am J Vet Res 2013 Jan;74(1):102-9.
    pubmed: 23270353doi: 10.2460/ajvr.74.1.102google scholar: lookup
  11. Cohen ND, Kuskie KR, Smith JL, Slovis NM, Brown SE 2nd, Stepusin RS, Chaffin MK, Takai S, Carter CN. Association of airborne concentration of virulent Rhodococcus equi with location (stall versus paddock) and month (January through June) on 30 horse breeding farms in central Kentucky.. Am J Vet Res 2012 Oct;73(10):1603-9.
    pubmed: 23013187doi: 10.2460/ajvr.73.10.1603google scholar: lookup
  12. Martens RJ, Takai S, Cohen ND, Chaffin MK, Liu H, Sakurai K, Sugimoto H, Lingsweiler SW. Association of disease with isolation and virulence of Rhodococcus equi from farm soil and foals with pneumonia.. J Am Vet Med Assoc 2000 Jul 15;217(2):220-5.
    pubmed: 10909463doi: 10.2460/javma.2000.217.220google scholar: lookup
  13. Grimm MB, Cohen ND, Slovis NM, Mundy GD, Harrington JR, Libal MC, Takai S, Martens RJ. Evaluation of fecal samples from mares as a source of Rhodococcus equi for their foals by use of quantitative bacteriologic culture and colony immunoblot analyses.. Am J Vet Res 2007 Jan;68(1):63-71.
    pubmed: 17199420doi: 10.2460/ajvr.68.1.63google scholar: lookup
  14. Buntain S, Carter C, Kuskie K. Frequency of Rhodococcus equi in feces of mares in Central Kentucky.. J Equine Vet Sci 2010;30:191‐195.
  15. Chirino-Trejo JM, Prescott JF, Yager JA. Protection of foals against experimental Rhodococcus equi pneumonia by oral immunization.. Can J Vet Res 1987 Oct;51(4):444-7.
    pmc: PMC1255362pubmed: 3453264
  16. Hooper-McGrevy KE, Wilkie BN, Prescott JF. Virulence-associated protein-specific serum immunoglobulin G-isotype expression in young foals protected against Rhodococcus equi pneumonia by oral immunization with virulent R. equi.. Vaccine 2005 Dec 30;23(50):5760-7.
    pubmed: 16112256doi: 10.1016/j.vaccine.2005.07.050google scholar: lookup
  17. Chaffin MK, Cohen ND, Martens RJ, Edwards RF, Nevill M. Foal-related risk factors associated with development of Rhodococcus equi pneumonia on farms with endemic infection.. J Am Vet Med Assoc 2003 Dec 15;223(12):1791-9.
    pubmed: 14690209doi: 10.2460/javma.2003.223.1791google scholar: lookup
  18. Chaffin MK, Cohen ND, Martens RJ. Evaluation of equine breeding farm management and preventative health practices as risk factors for development of Rhodococcus equi pneumonia in foals.. J Am Vet Med Assoc 2003 Feb 15;222(4):476-85.
    pubmed: 12597421doi: 10.2460/javma.2003.222.476google scholar: lookup
  19. Cohen ND, O'Conor MS, Chaffin MK, Martens RJ. Farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals.. J Am Vet Med Assoc 2005 Feb 1;226(3):404-13.
    pubmed: 15702691doi: 10.2460/javma.2005.226.404google scholar: lookup
  20. Sellon DC, Besser TE, Vivrette SL, McConnico RS. Comparison of nucleic acid amplification, serology, and microbiologic culture for diagnosis of Rhodococcus equi pneumonia in foals.. J Clin Microbiol 2001 Apr;39(4):1289-93.
    pmc: PMC87926pubmed: 11283043doi: 10.1128/jcm.39.4.1289-1293.2001google scholar: lookup
  21. Shaw SD, Cohen ND, Chaffin MK, Blodgett GP, Syndergaard M, Hurych D. Estimating the Sensitivity and Specificity of Real-Time Quantitative PCR of Fecal Samples for Diagnosis of Rhodococcus equi Pneumonia in Foals.. J Vet Intern Med 2015 Nov-Dec;29(6):1712-7.
    pmc: PMC4895660pubmed: 26436545doi: 10.1111/jvim.13631google scholar: lookup
  22. Madrigal RG, Shaw SD, Witkowski LA, Sisson BE, Blodgett GP, Chaffin MK, Cohen ND. Use of Serial Quantitative PCR of the vapA Gene of Rhodococcus equi in Feces for Early Detection of R. equi Pneumonia in Foals.. J Vet Intern Med 2016 Mar-Apr;30(2):664-70.
    pmc: PMC4913589pubmed: 26806422doi: 10.1111/jvim.13828google scholar: lookup
  23. Takai S, Iimori S, Tsubaki S. Quantitative fecal culture for early diagnosis of Corynebacterium (Rhodococcus) equi enteritis in foals.. Can J Vet Res 1986 Oct;50(4):479-84.
    pmc: PMC1255252pubmed: 3791074
  24. Takai S, Fujimori T, Katsuzaki K, Tsubaki S. Ecology of Rhodococcus equi in horses and their environment on horse-breeding farms.. Vet Microbiol 1987 Aug;14(3):233-9.
    pubmed: 3672865doi: 10.1016/0378-1135(87)90110-6google scholar: lookup
  25. Takai S, Ohkura H, Watanabe Y, Tsubaki S. Quantitative aspects of fecal Rhodococcus (Corynebacterium) equi in foals.. J Clin Microbiol 1986 Apr;23(4):794-6.
    pmc: PMC362841pubmed: 3700632doi: 10.1128/jcm.23.4.794-796.1986google scholar: lookup
  26. Takai S, Takahagi J, Sato Y. Molecular epidemiology of virulent in horses and their environments.. Equine Infectious Disease VII 1994:183‐187.
  27. Pusterla N, Wilson WD, Mapes S, Leutenegger CM. Diagnostic evaluation of real-time PCR in the detection of Rhodococcus equi in faeces and nasopharyngeal swabs from foals with pneumonia.. Vet Rec 2007 Aug 25;161(8):272-5.
    pubmed: 17720966doi: 10.1136/vr.161.8.272google scholar: lookup
  28. Rocha JN, Cohen ND, Bordin AI, Brake CN, Giguère S, Coleman MC, Alaniz RC, Lawhon SD, Mwangi W, Pillai SD. Oral Administration of Electron-Beam Inactivated Rhodococcus equi Failed to Protect Foals against Intrabronchial Infection with Live, Virulent R. equi.. PLoS One 2016;11(2):e0148111.
    pmc: PMC4735123pubmed: 26828865doi: 10.1371/journal.pone.0148111google scholar: lookup
  29. Cywes-Bentley C, Rocha JN, Bordin AI, Vinacur M, Rehman S, Zaidi TS, Meyer M, Anthony S, Lambert M, Vlock DR, Giguère S, Cohen ND, Pier GB. Antibody to Poly-N-acetyl glucosamine provides protection against intracellular pathogens: Mechanism of action and validation in horse foals challenged with Rhodococcus equi.. PLoS Pathog 2018 Jul;14(7):e1007160.
    pmc: PMC6053243pubmed: 30024986doi: 10.1371/journal.ppat.1007160google scholar: lookup
  30. Bordin AI, Cohen ND, Giguère S, Bray JM, Berghaus LJ, Scott B, Johnson R, Hook M. Host-directed therapy in foals can enhance functional innate immunity and reduce severity of Rhodococcus equi pneumonia.. Sci Rep 2021 Jan 28;11(1):2483.
    pmc: PMC7844249pubmed: 33510265doi: 10.1038/s41598-021-82049-ygoogle scholar: lookup
  31. Wada R, Kamada M, Anzai T, Nakanishi A, Kanemaru T, Takai S, Tsubaki S. Pathogenicity and virulence of Rhodococcus equi in foals following intratracheal challenge.. Vet Microbiol 1997 Jun 16;56(3-4):301-12.
    pubmed: 9226844doi: 10.1016/s0378-1135(97)00098-9google scholar: lookup
  32. Jacks S, Giguère S. Effects of inoculum size on cell-mediated and humoral immune responses of foals experimentally infected with Rhodococcus equi: a pilot study.. Vet Immunol Immunopathol 2010 Feb 15;133(2-4):282-6.
    pubmed: 19720402doi: 10.1016/j.vetimm.2009.08.004google scholar: lookup
  33. Sanz M, Loynachan A, Sun L, Oliveira A, Breheny P, Horohov DW. The effect of bacterial dose and foal age at challenge on Rhodococcus equi infection.. Vet Microbiol 2013 Dec 27;167(3-4):623-31.
    pubmed: 24139178doi: 10.1016/j.vetmic.2013.09.018google scholar: lookup
  34. Francis-Smith K, Wood-Gush DG. Coprophagia as seen in thoroughbred foals.. Equine Vet J 1977 Jul;9(3):155-7.
    pubmed: 560965doi: 10.1111/j.2042-3306.1977.tb04010.xgoogle scholar: lookup
  35. Crowell-Davis SL, Houpt KA. Coprophagy by foals: effect of age and possible functions.. Equine Vet J 1985 Jan;17(1):17-9.
    pubmed: 4038939doi: 10.1111/j.2042-3306.1985.tb02030.xgoogle scholar: lookup
  36. Reuss SM, Chaffin MK, Cohen ND. Extrapulmonary disorders associated with Rhodococcus equi infection in foals: 150 cases (1987-2007).. J Am Vet Med Assoc 2009 Oct 1;235(7):855-63.
    pubmed: 19793018doi: 10.2460/javma.235.7.855google scholar: lookup

Citations

This article has been cited 2 times.
  1. da Silveira BP, Kahn SK, Legere RM, Bray JM, Cole-Pfeiffer HM, Golding MC, Cohen ND, Bordin AI. Enteral immunization with live bacteria reprograms innate immune cells and protects neonatal foals from pneumonia. Sci Rep 2025 May 25;15(1):18156.
    doi: 10.1038/s41598-025-02060-5pubmed: 40415003google scholar: lookup
  2. da Silveira BP, Cohen ND, Lawhon SD, Watson RO, Bordin AI. Protective immune response against Rhodococcus equi: An innate immunity-focused review. Equine Vet J 2025 May;57(3):563-586.
    doi: 10.1111/evj.14214pubmed: 39258739google scholar: lookup
Subscribe to our newsletter
Join 99,727 horse owners like you who receive our email updates on horse health and nutrition.