Comparison of a Single-Shot Antibiotic Protocol Compared to a Conventional 5-Day Antibiotic Protocol in Equine Diagnostic Laparotomy Regarding Pre- and Postoperative Colonization with Multi-Drug-Resistant Indicator Pathogens.
Abstract: The emergence and spread of multi-drug-resistant (MDR) bacteria pose a growing threat in veterinary medicine, particularly in equine hospitals. This study investigated the colonization and infection dynamics of horses undergoing emergency laparotomy with two distinct antibiotic protocols (single-shot versus 5-day protocol) during hospitalization. Nasal swabs and fecal samples were collected from 67 horses undergoing emergency laparotomy at clinic admission as well as on postoperative days 3 and 10. These were screened for multi-drug-resistant indicator pathogens. As multi-drug-resistant indicator pathogens, methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-E), and bacteria belonging to the complex were defined. Preoperatively, 6.2% of horses tested positive for MRSA and 13% for ESBL-E. An increase in colonization was observed on day 3 postoperatively, with 62.1% of nasal swabs and 86.4% of fecal samples testing positive for MDR organisms. On day 10, 53.4% of nasal swabs and 62.5% of fecal samples tested positive for indicator pathogens. Surgical site infection developed in five horses, two of which tested positive for MRSA in both nasal and wound samples during hospitalization, supporting the potential role of nasal carriage as a source of infection. Furthermore, all horses tested positive for ESBL-E during at least one time-point during hospitalization, and Enterobacterales (MDR in two surgical site infections (SSI)) were involved in all surgical site infections. No significant differences were observed between the two antibiotic treatment groups regarding colonization rates with indicator pathogens during hospitalization. However, the results indicate that hospitalization itself contributes to increased colonization with resistant bacteria. A clear limitation of the study is the restricted number of sampled horses and the lack of environmental contamination data. Non-sampled hospitalized horses with and without antibiotic treatment may have acted as reservoirs for MDR bacteria. The findings emphasize the need for routine environmental monitoring and strict adherence to hygiene protocols in equine clinics to reduce the risk of nosocomial transmission. Ongoing surveillance and infection control strategies are essential to mitigate the spread of MDR pathogens in veterinary settings.
Publication Date: 2026-01-21 PubMed ID: 41594143PubMed Central: PMC12837582DOI: 10.3390/antibiotics15010106Google 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.
- 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.
Study Overview
- This study compared the effects of a single-shot antibiotic protocol versus a conventional 5-day antibiotic protocol on the colonization of multi-drug-resistant (MDR) bacteria in horses undergoing emergency diagnostic laparotomy.
- The researchers monitored preoperative and postoperative colonization of MDR pathogens to assess how antibiotic treatment and hospitalization influence bacterial colonization and surgical site infections.
Background and Importance
- Multi-drug-resistant bacteria are an increasing concern in veterinary medicine due to the difficulty in treating infections and the risk of these pathogens spreading within equine hospitals.
- Equine patients undergoing surgery, particularly emergency laparotomies, are susceptible to colonization and infection by bacteria resistant to multiple antibiotics, complicating post-surgical recovery.
- Understanding how different antibiotic protocols impact colonization with MDR pathogens may help optimize prophylactic treatment and reduce infection rates.
Study Design and Methods
- Subjects: 67 horses undergoing emergency laparotomy at an equine clinic.
- Sample Collection: Nasal swabs and fecal samples were taken at three time points—upon admission (preoperative), and on postoperative days 3 and 10.
- Antibiotic Protocols Compared:
- Single-shot antibiotic treatment given preoperatively
- Conventional 5-day antibiotic course following surgery
- Pathogen Testing: Samples were screened for indicator MDR pathogens:
- MRSA (methicillin-resistant Staphylococcus aureus)
- ESBL-producing Enterobacterales (ESBL-E)
- Bacteria belonging to other MDR complexes
Key Findings
- Preoperative colonization rates:
- 6.2% of horses positive for MRSA in nasal or fecal samples
- 13% positive for ESBL-producing Enterobacterales
- Postoperative increase in colonization:
- On day 3, 62.1% of nasal and 86.4% of fecal samples tested positive for MDR pathogens
- On day 10, colonization remained high with 53.4% nasal and 62.5% fecal samples positive
- Surgical site infections (SSI):
- Developed in 5 horses
- 2 horses with SSI had MRSA detected in both nasal and wound samples during hospitalization, suggesting nasal carriage as an infection source
- All SSI cases involved Enterobacterales, with 2 involving MDR strains
- No significant difference was found in MDR colonization rates between horses treated with the single-shot versus the 5-day antibiotic protocol.
- The increase in colonization during hospitalization implies that the hospital environment and factors other than antibiotic regimen contribute to the spread of MDR bacteria.
Study Limitations
- Sample size was limited to 67 horses, restricting statistical power and generalizability.
- Lack of environmental sampling meant the role of hospital surfaces and other horses as reservoirs of MDR bacteria could not be evaluated.
- Non-sampled hospitalized horses receiving or not receiving antibiotics might have contributed to the spread of MDR bacteria, complicating attribution of colonization sources.
Implications and Recommendations
- Hospitalization itself significantly increases colonization with MDR bacteria, regardless of the antibiotic protocol used.
- Nasal carriage in horses may serve as a reservoir for MRSA and could be important in managing and preventing SSIs.
- Strict infection control measures, routine environmental monitoring, and adherence to hygiene protocols in equine clinics are critical to reduce nosocomial transmission of MDR pathogens.
- Ongoing surveillance of MDR bacteria and further research into antibiotic stewardship in veterinary surgical settings are necessary to inform evidence-based guidelines.
Cite This Article
APA
Stöckle SD, Kannapin DA, Merle R, Lübke-Becker A, Gehlen H.
(2026).
Comparison of a Single-Shot Antibiotic Protocol Compared to a Conventional 5-Day Antibiotic Protocol in Equine Diagnostic Laparotomy Regarding Pre- and Postoperative Colonization with Multi-Drug-Resistant Indicator Pathogens.
Antibiotics (Basel), 15(1), 106.
https://doi.org/10.3390/antibiotics15010106 Publication
Researcher Affiliations
- Equine Clinic: Surgery and Radiology, Freie Universität Berlin, 14163 Berlin, Germany.
- Equine Clinic: Surgery and Radiology, Freie Universität Berlin, 14163 Berlin, Germany.
- Institute of Veterinary Epidemiology and Biostatistics, Veterinary Centre for Resistance Research, Freie Universität Berlin, 14163 Berlin, Germany.
- Institute of Microbiology and Epizootics, Veterinary Centre for Resistance Research, Freie Universität Berlin, 14163 Berlin, Germany.
- Equine Clinic: Surgery and Radiology, Freie Universität Berlin, 14163 Berlin, Germany.
Grant Funding
- grant Nos. 01KI1727F and 01KI1727D / German Federal Ministry of Education and Research (BMBF).
Conflict of Interest Statement
The authors declare no conflicts of interest.
References
This article includes 32 references
- Mair TS, Smith LJ. Survival and Complication Rates in 300 Horses Undergoing Surgical Treatment of Colic. Part 2: Short-term Complications.. Equine Vet. J. 2005;37:303–309.
- Gehlen H, Klein KS, Merle R, Lübke-Becker A, Stoeckle SD. Does Colonization with MRSA, ESBL—Producing Enterobacteriaceae, and/or Acinetobacter baumannii—Increase the Risk for Postoperative Surgical Site Infection?. Vet. Med. Sci. 2023;9:729–737.
- Bergstrom K, Bengtsson B, Nyman A, Gronlund Andersson U. Longitudinal Study of Horses for Carriage of Methicillin-Resistant Staphylococcus aureus Following Wound Infections.. Vet. Microbiol. 2013;163:388–391.
- Boerlin P, Eugster S, Gaschen F, Straub R, Schawalder P. Transmission of Opportunistic Pathogens in a Veterinary Teaching Hospital.. Vet. Microbiol. 2001;82:347–359.
- Seguin JC, Walker RD, Caron JP, Kloos WE, George CG, Hollis RJ, Jones RN, Pfaller MA. Methicillin-Resistant Staphylococcus aureus Outbreak in a Veterinary Teaching Hospital: Potential Human-to-Animal Transmission.. J. Clin. Microbiol. 1999;37:1459–1463.
- Walther B, Tedin K, Lübke-Becker A. Multidrug-Resistant Opportunistic Pathogens Challenging Veterinary Infection Control.. Vet. Microbiol. 2017;200:71–78.
- Wieler LH, Ewers C, Guenther S, Walther B, Lübke-Becker A. Methicillin-Resistant Staphylococci (MRS) and Extended-Spectrum Beta-Lactamases (ESBL)-Producing Enterobacteriaceae in Companion Animals: Nosocomial Infections as One Reason for the Rising Prevalence of These Potential Zoonotic Pathogens in Clinical Samples.. Int. J. Med. Microbiol. 2011;301:635–641.
- Walther B, Wieler LH, Friedrich AW, Kohn B, Brunnberg L, Luebke-Becker A. Staphylococcus aureus and MRSA Colonization Rates among Personnel and Dogs in a Small Animal Hospital: Association with Nosocomial Infections.. Berl. Munch. Tierarztl. Wochenschr. 2009;122:178–185.
- Weese JS. A Review of Post-Operative Infections in Veterinary Orthopaedic Surgery.. Vet. Comp. Orthop. Traumatol. 2008;21:99–105.
- Hauschild G, Nolte I, Litzke L-F. Verhütung Nosokomialer Infektionen.. In: Dietz O., Lietzke L.-F., editors. Lehrbuch der Allgemeinen Chirurgie für Tiermediziner. Enke; Stuttgart, Germany: 2004. pp. 63–69.
- Koterba A, Torchia J, Silverthorne C, Ramphal R, Merritt AM, Manucy J. Nosocomial Infections and Bacterial Antibiotic Resistance in a University Equine Hospital.. J. Am. Vet. Med. Assoc. 1986;189:185–191.
- Båverud V, Gustafsson A, Franklin A, Aspan A, Gunnarsson A. Clostridium Difficile: Prevalence in Horses and Environment, and Antimicrobial Susceptibility.. Equine Vet. J. 2003;35:465–471.
- Ahern BJ, Richardson DW. Chapter 7—Surgical Site Infection and the Use of Antimicrobials.. In: Auer J.A., Richardson D.W., editors. Equine Surgery. W.B. Saunders; Saint Louis, MO, USA: 2011. pp. 68–74.
- Zastrow K-D. Krankenhausinfektionen—Ein Medizinisches, Soziales Und Ökonomisches Problem.. Passion Chir. 2016:13–15.
- Durward-Akhurst SA, Mair TS, Boston R, Dunkel B. Comparison of Two Antimicrobial Regimens on the Prevalence of Incisional Infections after Colic Surgery.. Vet. Rec. 2013;172:287.
- Stöckle S.D., Kannapin D.A., Kauter A.M.L., Lübke-Becker A., Walther B., Merle R., Gehlen H. A Pilot Randomised Clinical Trial Comparing a Short-Term Perioperative Prophylaxis Regimen to a Long-Term Standard Protocol in Equine Colic Surgery. Antibiotics. 2021;10:587. doi: 10.3390/antibiotics10050587.
- Christie K.D., Epstein K.L., Tyma J.F., Afonso T., Fultz L.E., Giguère S. Prospective Randomised Comparison of Different Antimicrobial Protocols for the Prevention of Surgical Site Infections in Horses Undergoing Emergency Exploratory Celiotomy. Equine Vet. J. 2025;57:1478–1489. doi: 10.1111/evj.14489.
- Johns I., Verheyen K., Good L., Rycroft A. Antimicrobial Resistance in Faecal Escherichia Coli Isolates from Horses Treated with Antimicrobials: A Longitudinal Study in Hospitalised and Non-Hospitalised Horses. Vet. Microbiol. 2012;159:381–389. doi: 10.1016/j.vetmic.2012.04.010.
- Williams A., Christley R.M., McKane S.A., Roberts V.L., Clegg P.D., Williams N.J. Antimicrobial Resistance Changes in Enteric Escherichia Coli of Horses during Hospitalisation: Resistance Profiling of Isolates. Vet. J. 2013;195:121–126. doi: 10.1016/j.tvjl.2012.08.001.
- Kauter A., Brombach J., Lübke-Becker A., Kannapin D., Bang C., Franzenburg S., Stoeckle S.D., Mellmann A., Scherff N., Köck R., et al. Antibiotic Prophylaxis and Hospitalization of Horses Subjected to Median Laparotomy: Gut Microbiota Trajectories and Abundance Increase of Escherichia. Front. Microbiol. 2023;14 doi: 10.3389/fmicb.2023.1228845.
- Walther B., Klein K.-S., Barton A.-K., Semmler T., Huber C., Wolf S.A., Tedin K., Merle R., Mitrach F., Guenther S. Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia Coli and Acinetobacter Baumannii among Horses Entering a Veterinary Teaching Hospital: The Contemporary” Trojan Horse”. PLoS ONE. 2018;13:e0191873. doi: 10.1371/journal.pone.0191873.
- Weese J.S., Rousseau J., Willey B.M., Archambault M., McGeer A., Low D.E. Methicillin-resistant Staphylococcus aureus in Horses at a Veterinary Teaching Hospital: Frequency, Characterization, and Association with Clinical Disease. J. Vet. Intern. Med. 2006;20:182–186. doi: 10.1892/0891-6640(2006)20[182:msaiha]2.0.co;2.
- Walther B., Klein K.S., Barton A.K., Semmler T., Huber C., Merle R., Tedin K., Mitrach F., Lübke-Becker A., Gehlen H. Equine Methicillin-Resistant Sequence Type 398 Staphylococcus aureus (MRSA) Harbor Mobile Genetic Elements Promoting Host Adaptation. Front. Microbiol. 2018;9 doi: 10.3389/fmicb.2018.02516.
- Maddox T.W., Clegg P.D., Williams N.J., Pinchbeck G.L. Antimicrobial Resistance in Bacteria from Horses: Epidemiology of Antimicrobial Resistance. Equine Vet. J. 2015;47:756–765. doi: 10.1111/evj.12471.
- McConnico R.S., Roberts M.C., Tompkins M. Penicillin-Induced Immune-Mediated Hemolytic Anemia in a Horse. J. Am. Vet. Med. Assoc. 1992;291:1402–1403.
- Blue J.T., Dinsmore R.P., Anderson K.L. Immune-Mediated Hemolytic Anemia Induced by Penicillin in Horses. Cornell Vet. 1987;77:263–276.
- Step D.L., Blue J.T., Dill S.G. Penicillin-Induced Hemolytic Anemia and Acute Hepatic Failure Following Treatment of Tetanus in a Horse. Cornell Vet. 1991;81:13–18.
- Robbins R.L., Wallace S.S., Brunner C.J., Gardner T.R., DiFranco B.J., Speirs V.C. Immune-mediated Haemolytic Disease after Penicillin Therapy in a Horse. Equine Vet. J. 1993;25:462–465. doi: 10.1111/j.2042-3306.1993.tb02992.x.
- Magiorakos A.-P., Srinivasan A., Carey R.B., Carmeli Y., Falagas M.E., Giske C.G., Harbarth S., Hindler J.F., Kahlmeter G., Olsson-Liljequist B., et al. Multidrug-Resistant, Extensively Drug-Resistant and Pandrug-Resistant Bacteria: An International Expert Proposal for Interim Standard Definitions for Acquired Resistance. Clin. Microbiol. Infect. 2012;18:268–281. doi: 10.1111/j.1469-0691.2011.03570.x.
- CLSI Vet01-S2 Performance Standards for Antimicrobial Disk and Dilution Susceptibility for Bacteria Isolated from Animals. Second International Supplement. Clinical and Laboratory Standards Institute; Wayne, PA, USA: 2013.
- CLSI Clinical and Laboratory Standards Institute: Performance Standards for Antimicrobial Susceptibility Testing: Twenty-First Informational Supplement M100-S21. Clinical and Laboratory Standards Institute; Wayne, PA, USA: 2011.
- Schwarz S., Silley P., Simjee S., Woodford N., van Duijkeren E., Johnson A.P., Gaastra W. Assessing the Antimicrobial Susceptibility of Bacteria Obtained from Animals. Vet. Microbiol. 2010;141:1–4. doi: 10.1016/j.vetmic.2009.12.013.
Citations
This article has been cited 0 times.Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
