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- Malaluang, Pongpreecha, et al.
(författare)
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Antimicrobial Resistance in Equine Reproduction
- 2021
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Ingår i: Animals. - : MDPI. - 2076-2615. ; 11:11
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Forskningsöversikt (refereegranskat)abstract
- Simple SummaryBacteria can develop resistance to antibiotics, resulting in the appearance of infections that are difficult or impossible to treat. This ability enables bacteria to survive in hostile environments and can result from exposure to even small amounts of antibiotic substances. Bacteria are present in the reproductive tract of the horse; they can develop resistance to antibiotics, because the animal has been treated for an infection, or due to insemination with a semen dose that contains antibiotics. Bacteria colonize the membrane lining the male reproductive tract and are transferred to the semen during collection. They can cause sperm quality to deteriorate during storage or may cause an infection in the mare. Therefore, antibiotics are added to the semen dose, according to legislation. However, these antibiotics may contribute to the development of resistance. Current recommendations are that antibiotics should only be used to treat bacterial infections and where the sensitivity of the bacterium to the antibiotic has first been established. Therefore, adding antibiotics to semen extenders does not fit these recommendations. In this review, we examine the effects of bacteria in semen and in the inseminated mare, and possible alternatives to their use.Bacteria develop resistance to antibiotics following low-level "background " exposure to antimicrobial agents as well as from exposure at therapeutic levels during treatment for bacterial infections. In this review, we look specifically at antimicrobial resistance (AMR) in the equine reproductive tract and its possible origin, focusing particularly on antibiotics in semen extenders used in preparing semen doses for artificial insemination. Our review of the literature indicated that AMR in the equine uterus and vagina were reported worldwide in the last 20 years, in locations as diverse as Europe, India, and the United States. Bacteria colonizing the mucosa of the reproductive tract are transferred to semen during collection; further contamination of the semen may occur during processing, despite strict attention to hygiene at critical control points. These bacteria compete with spermatozoa for nutrients in the semen extender, producing metabolic byproducts and toxins that have a detrimental effect on sperm quality. Potential pathogens such as Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa may occasionally cause fertility issues in inseminated mares. Antibiotics are added during semen processing, according to legislation, to impede the growth of these microorganisms but may have a detrimental effect on sperm quality, depending on the antimicrobial agent and concentration used. However, this addition of antibiotics is counter to current recommendations on the prudent use of antibiotics, which recommend that antibiotics should be used only for therapeutic purposes and after establishing bacterial sensitivity. There is some evidence of resistance among bacteria found in semen samples. Potential alternatives to the addition of antibiotics are considered, especially physical removal separation of spermatozoa from bacteria. Suggestions for further research with colloid centrifugation are provided.
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- Malaluang, Pongpreecha, et al.
(författare)
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Antimicrobial Resistance in Vaginal Bacteria in Inseminated Mares
- 2023
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Ingår i: Pathogens. - : MDPI AG. - 2076-0817. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Antimicrobials are added to semen extenders to inhibit the growth of bacteria that are transferred to the semen during collection. However, this non-therapeutic use of antimicrobials could contribute to the development of antimicrobial resistance. The objective of this study was to determine changes in the antibiotic susceptibility of vaginal microbiota after artificial insemination. Swabs were taken from the vagina of 26 mares immediately before artificial insemination and again 3 days later. Bacteria isolated from the vagina at both time points were subjected to antibiotic susceptibility testing and whole-genome sequencing. In total, 32 bacterial species were identified. There were increases in the resistance of Escherichia coli to trimethoprim (p = 0.0006), chloramphenicol and (p = 0.012) tetracycline (p = 0.03) between day 0 and day 3. However, there was no significant effect of exposure to antibiotics in semen extenders with respect to the resistance of Staphylococcus simulans and Streptococcus equisimilis (p > 0.05). Whole-genome sequencing indicated that most phenotypic resistance was associated with genes for resistance. These results indicate that the resistance patterns of vaginal bacteria may be affected by exposure to antibiotics; therefore, it would be prudent to minimize, or preferably, avoid using antibiotics in semen extenders.
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- Malaluang, Pongpreecha, et al.
(författare)
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Bacteria in the healthy equine vagina during the estrous cycle
- 2024
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Ingår i: Theriogenology. - 0093-691X .- 1879-3231. ; 213, s. 11-18
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Tidskriftsartikel (refereegranskat)abstract
- An understanding of the normal bacterial microbiota of any organ is essential to provide the background to conditions and interventions that might cause the microbiota to change. In the vagina of the mare, a change of bacterial microbiota could be induced by introduction of semen, treatment with antibiotics, discharge from an unhealthy uterus etc. Previous studies on equine vaginal bacteria are not all conducted in the same way and results are not altogether consistent. Therefore, this study was designed to provide a deeper understanding of the bacterial microbiota of the mare vagina, and possible changes throughout the estrous cycle. The cranial portion of the vagina was sampled on day 0 (ovulation), day 3, day 7, and day 14 of the estrous cycle. The vaginal sampling was conducted with double-guarded occluded swabs from the cranial floor of the vagina. Ovulation was determined by rectal palpation and ultrasonic examination, and the day 0 samples were taken within ±24 h of ovulation. Swabs were brought to the laboratory in Amies medium within 2–3 h and were plated out immediately on both selective and non-selective agars. Results were registered as amount of growth (qualitatively), bacterial species and number of isolates. Bacterial growth was highest on day 3 and 7, representing the beginning and middle of diestrus. The dominant bacteria were Escherichia coli and Streptococcus zooepidemicus. Escherichia coli was especially dominant in maiden mares, compared to the mares that had foaled. An increase in bacterial diversity throughout the estrous cycle was observed, being highest on day 14. These results suggest that there are changes in the bacterial microbiota of the mare vagina throughout the normal estrous cycle.
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- Malaluang, Pongpreecha, et al.
(författare)
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Vaginal Bacteria in Mares and the Occurrence of Antimicrobial Resistance
- 2022
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Ingår i: Microorganisms. - : MDPI AG. - 2076-2607. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Antibiotics are added to semen extenders in insemination doses but their effect on the vaginal microbiota of the inseminated female is unknown. The objectives of this study were to define the equine vaginal microbiota and its antimicrobial resistance, and to determine whether it changes after exposure to antibiotics in semen extenders. Vaginal swabs were taken prior to sham-insemination (day 0), and again on days 3, 7, and 14 after insemination. Isolated bacteria were identified by MALDI-TOF and tested for antimicrobial susceptibility by microdilution. The bacteria isolated from the vagina differed according to reproductive status (brood mare or maiden mare), location (north or middle of Sweden), and the stage of the estrous cycle. Five bacterial species were frequently isolated from mares in both locations: Escherichia coli, Staphylococcus capitis, Streptococcus equisimilis, Streptococcus thoraltensis, and Streptococcus zooepidemicus. Overall, vaginal bacteria isolated from inseminated mares showed higher antibiotic resistance than from non-inseminated mares, suggesting a possible link between exposure to antibiotics in the semen extender and the appearance of antimicrobial resistance. The whole-genome sequencing of E. coli isolates from inseminated mares revealed some genes which are known to confer antimicrobial resistance; however, some instances of resistance in these isolates were not characteristic of induced AMR.
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