(Dr. Tanja Witte, presentation, Cambridge, UK.)
Concentrations of gentamicin in serum, intrauterine fluid, and endometrial tissue after intravenous administration in healthy mares.
(TS Witte, K Hahn, S Duerr and LS Goehring)
Centre for Clinical Veterinary Medicine, Division of Equine Medicine & Reproduction, Ludwig-Maximilians University, Munich, Germany.
Endometritis in mares remains an important clinical condition for the equine breeding industry. The treatment of choice is antimicrobial therapy, commonly administered into the uterus. Disadvantages of the intrauterine (i.u.) route, however, include the risk of contamination, dependence on estrous cycle stage and inhomogeneous distribution within the endometrium. Therefore, the objective of the present study was to assess gentamicin concentrations in serum, i.u. fluid (IUF), and endometrial tissue (ET) of non-pregnant healthy mares after intravenous (i.v.) gentamicin administration.
We hypothesized that gentamicin concentrations in IUF and ET reach concentrations greater than the minimal inhibitory concentration (MIC) reported for common equine pathogens. 16 mares in estrus were examined for signs of i.u. inflammation, followed by i.u. bacteriological and cytological analysis. Thereafter, each mare was treated with a single dose of gentamicin (6.6 mg/kg BW i.v.) in two consecutive cycles. In both cycles, blood was obtained immediately before (0h) and 1, 2, 4, 6, and 24h after treatment. In the first cycle, IUF was harvested from 16 mares at 0, 1, 2, 4, 6, and 24h using a modified Salivette®-technique.
In the consecutive cycle, endometrial biopsies were obtained from 12 mares at 0, 2, and 24h with a Kevorkian biopsy forceps. Bacteriological and cytological samples were additionally harvested at the end of the study. Gentamicin concentrations were detected using photometry for serum and IUF samples, and a commercial ELISA for ET samples.
All mares were gynecologically healthy at the start of the study and did not receive any medical treatments within 10d before sampling. Mean gentamicin concentrations reached values above the reported MIC for common equine pathogens (4 µg/mL) at 1, 2, and 4h after treatment in serum and IUF samples. In IUF samples the MIC was also reached 6h after treatment. Mean (± SD) gentamicin peak concentrations 1h after treatment in serum were 15.68 ± 2.30 µg/mL in the 1st cycle and 17.2 ± 4.03 µg/mL in the 2nd cycle, while IUF gentamicin peak concentrations were 14.94 ± 10.79 µg/mL. In ET samples, mean (± SD) gentamicin peak concentrations were reached 2h after treatment (5.0 ± 0.18 µg/g), and remained above the MIC by 24h (4.8 ± 0.53 µg/g). Pharmacokinetic evaluation indicated an equal distribution of gentamicin with a mean (± SD) half-life of 2.2 ± 0.1h and 2.3 ± 0.3h for serum and IUF, respectively. The volume of distribution was 256.6 ± 67.9 ml/kg BW and 254.8 ± 154.4 ml/kg BW for serum and IUF, respectively. After sampling, two mares showed mild IUF accumulation with increased neutrophil counts, while another mare showed a mixed bacterial growth without clinical signs of endometritis. Gynecological examination of all other mares was unremarkable. The presented results support the systemic administration of gentamicin as an effective alternative treatment option in mares with endometritis.
(Dr. Christiane Otzdorff, poster presentation, Cambridge, UK.)
EHV-1 infection of the equine male genital tract
(C Otzdorff1*, K Gießler1, C Haupt1, S Samoilowa1, G Soboll Hussey2, M Kiupel2, K Matiasek3, LS Goehring)
1. Centre for Clinical Veterinary Medicine, Division of Medicine and Reproduction, Ludwig-Maximilians University, Munich, Germany.
2. Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, USA.
3. Centre for Clinical Veterinary Medicine, Clinical & Comparative Neuropathology, Ludwig-Maximilians-University, Munich, Germany.
EHV-1 infection of the equine male genital tract Equid Herpesvirus (EHV-1) causes respiratory tract infections in horse populations world-wide. In addition, infection is associated with herd outbreaks of myeloencephalopathy and abortion following a cell-associated viremia. EHV-1 also crosses the blood-testis barrier and is shed with semen in the intact male, lasting typically for several weeks following viremia. As barrier damage is key to myeloencephalopathy and abortion, specific aims of this study were to investigate whether virus can be detected in gonads and/or accessory sex glands of intact male horses 1 month after infection, and if there is evidence of tissue pathology. As part of a larger investigation, 5 seronegative yearling colts (Western Stock, age 10 – 13 months) were infected with EHV-1 strain Ab4 (1x107 TCID50) via nasopharyngeal instillation. Animals were euthanized one month after infection. Immediately after euthanasia tissue sections of both testicles and accessory sex glands were collected and fixed in 5% phosphate-buffered formalin. Testicles of 2 age-matched uninfected controls were included. All samples were prepared and stained for histopathological evaluation. Slides were read by at least 2 examiners. Furthermore, tissue sections were collected and prepared for quantitative EHV-1 specific genomic and transcriptional PCR analysis (qPCR and reverse transcriptase RT-qPCR). All animals were successfully infected and became viremic. Histological evaluation of testicular tissue showed variable amounts of seminiferous tubules. All expected cell types of prepubertal testicular tissue were detected. Spermatogenesis was absent most likely due to age and prepubertal status. Histopathologic examination showed moderate multi-focal monocytic/lymphocytic infiltrations in both, testicular tissue as well as accessory sex glands. Mild perivascular cuffing and damage to the germ cell layer were noticed. In comparison, monocytic/lymphocytic infiltrates were absent in the testicles of age-matched controls without known previous EHV-1 exposure. Twenty-five tissue samples (15 accessory sex glands, 10 testicles) were tested for EHV-1 using qPCR and RT-qPCR. Four out of 10 testicular samples from different animals tested positive for viral DNA. In a single animal the testicular sample and one of its accessory sex glands (ampulla ductus deferens) tested positive for viral DNA. Viral mRNA could not be detected in any of the samples. EHV-1 is present in the male gonads one month after infection. Results could not determine the exact localization of virus in the tissue sections. The stage of EHV-1 infection (lytic or a latent) was not determined and will require further investigation. Furthermore, the phenotype of germ cell and mononuclear cell populations containing EHV-1 will require further analysis. The monocytic/lymphocytic infiltrates and perivascular accumulations are hallmark findings of EHV-1 infection of the endometrium or the spinal cord, suggesting a similar pathogenesis for the male gonads.
Veröffentlichungen von Mitarbeitern der Abteilung Innere Medizin und Reproduktion ab 2014:
- Carine L. Holz, Dodd G. Sledge, Matti Kiupel, Rahul K. Nelli, Lutz S. Goehring, Gisela Soboll Hussey. Histopathologic Findings Following Experimental Equine Herpesvirus 1 Infection of Horses. Front. Vet. Sci., 04 March 2019 | https://doi.org/10.3389/fvets.2019.00059
- Goehring LS, Brandes K, Ashton LV, Wittenburg LA, Olea-Popelka FJ, Lunn DP, Soboll Hussey G. Anti-inflammatory drugs decrease infection of endothelial cells with EHV-1 in vitro. Equine Vet J. 2017, 49:629-636.
- Holz CL, Nelli RK, Wilson ME, Zarski LM, Azab W, Baumgardner R, Osterrieder N, Pease A, Zhang L, Hession S, Goehring LS, Hussey SB, Soboll Hussey G. Viral genes and cellular markers associated with neurological complications during herpesvirus infections. J Gen Virol. 2017 Jun;98(6):1439-1454.
- Hahn K., Witte T.S.: Die Plazentitis der Stute. Prakt Tierarzt 97:998-1008, 2016.
- Witte T.S. Endometritis bei der Stute. Kompakt Vet 2015, 3, 9.
- Witte Tanja S., Bartmann Claus P. Diagnose und Therapie der Endometritis der Stute. Witte T.S., Bartmann C.P., Diagnose und Therapie der Endometritis der Stute. Prakt. Tierarzt 2015, 96 (10) 1024-1030.
- Goehring LS. EHV-1 and EHM. Chapter in Equine Neurology 2nd ed. M.O. Furr and S. Reed (eds). (2015) Wiley – Blackwell, Ames, Iowa.
- Goehring LS. Equid Herpesvirus-associated Myeloencephalopathy. Chapter 90 in: Current Therapy in Equine Medicine 7th ed. (2014) N.E. Robinson and K.A. Sprayberry (eds). Saunders Elsevier, St.Louis, MO.
- Goehring LS. Gamma-Herpesviruses in Horses and Donkeys. Chapter 36, 155 - 157in: Current Therapy in Equine Medicine 7th ed.(2014) N.E. Robinson and K.A. Sprayberry (eds). Saunders Elsevier, St.Louis, MO.