rel="nofollow" href="#uf0c9ba69-c513-59ac-8891-b4a11decc901">Chapter 4).
Clean and dry the perineum of the mare (see Chapter 3).
Place a sterile obstetrical sleeve on the arm.
Place the guarded culture device into the palm of the hand.
Place sterile lubricant on the knuckles and down the length of the sleeve being careful not to get lubricant onto the palm. If the culture device becomes inundated with lubricant, it may be more difficult to obtain a diagnostic sample.
Rub lubricant from the knuckles onto the vulva, straighten the fingers and insert through the vulva.
Using a slight rotating motion, pass the hand into the vagina so that the mid‐forearm is to about the level of the vulva. This should enable palpation of the external cervical os.Figure 12.1 Kalayjian swab in the open position.Figure 12.2 McCullough swab in the open position.
Gently insert the index finger into the external cervical os. Sometimes the os may be off center, located slightly downward, or to the left or right of center.
Pass the index finger through the cervix to the last knuckle (metacarpo‐phalangeal joint). Usually one can detect when the fingertip enters the uterine body lumen. Pass the uterine culture instrument past the inserted index finger into the uterine body. Sometimes, if the cervical canal is under the influence of progesterone and is toned, the index finger may need to be removed prior to passing the culture device. The culture instrument may need to be pointed in a slightly downward direction when being passed through the cervix due to the dependent nature of the suspended uterus within the abdomen, especially in older broodmares.
As most culture devices used today have a guard over the inserted end, the inner swab/brush is subsequently pushed forward through the cap/guard.Figure 12.3 Uterine brush in the open position.
Gently press the swab or brush in contact with the endometrium and gently rotate in one direction. It is recommended that the swab/brush be in contact with the endometrium for 10–15 seconds.
The swab/brush is retracted back inside the outer guards and then the device is removed from the mare. Care should be taken when rotating the swab as excessive motion can result in breaking of the end of the swab (Figure 12.4).
Once the culture instrument has been withdrawn from the external cervical os, a cupped hand should be placed over the device to limit vaginal contamination to the swab/brush.
The swab should be immediately plated or transferred to a transport device with media such as a CultureSwab™ (Figure 12.5). Often the outer swab guard is removed from the inner guard before extending the swab/brush into a transport device to limit contamination from the outer guard.
Figure 12.4 Tip of a uterine culture instrument broken off in the uterine lumen.
Figure 12.5 Transport device for uterine cultures.
Interpretation
In mares with a dependent uterus, well over the brim of the pelvis, the swab may be subjected to the downward weight of the uterus, making breakage of the tip of the swab more likely. Breakage of the swab tip may occur particularly when the swab is rotated, thus caution should be used.
Note any discharge present on the sterile sleeve when the gloved arm is pulled from the vagina. There should not be any purulent or hemorrhagic discharge, only the lubricant and clear mucous should be present.
Ensure that the culture device is intact and that no part of the instrument was left within the mare's uterus/cervix/vagina.
Note any discharge on the tip of the culture device. It is not uncommon to see some mild hemorrhage on the culture device as it rubbed against the endometrium.
The most common pathogens of the equine uterus are Streptococcus equi subspecies zooepidemicus, Escherichia coli, Klebsiella species, Pseudomonas aeruginosa, and fungi, among others.
Heavy growth of one organism may have more significance than light growth of multiple organisms.
Uterine culture results should be correlated with uterine cytology and other reproductive findings to determine significance.
Further Reading
1 Hinrichs K, Cummings MR, Sertich, PL, Kenney RM. 1988. Clinical significance of aerobic bacterial flora of the uterus, vagina, vestibule, and clitoral fossa of clinically normal mares. J Am Vet Med Assoc 193(1): 72–5.
2 LeBlanc MM. 2010. Advances in the diagnosis and treatment of chronic infections and post‐mating induced endometritis in the mare. Reprod Dom Anim 45(suppl. 2): 21–7.
3 Nielsen JM. 2005. Endometritis in the mare: a diagnostic study comparing cultures from swab and biopsy. Theriogenology 64(3): 510–18.
13 Antimicrobiotic Sensitivity Testing
Jillian Bishop1 and Patrick M. McCue2
1 University of Kansas Health System, USA
2 Equine Reproduction Laboratory, Colorado State University, USA
Introduction
A Kirby–Bauer disk diffusion susceptibility test (agar disk diffusion test) is used to evaluate the effectiveness of specific antibiotics against aerobic bacterial organisms under in vitro culture conditions. A known quantity of bacteria are distributed evenly on the surface of the agar plate and a series of paper disks, each impregnated with one antibiotic, are placed on the surface of the agar plate. The zone of growth inhibition around each test disk is a measure of the sensitivity of the organism to the given antibiotic.
Equipment and Supplies
Mueller Hinton (MH) II agar plate: MH‐II agar plates with 5% sheep blood for Gram‐positive β‐hemolytic organisms, MH‐II agar plates without sheep blood for Gram‐negative organisms; sterile swab; antibiotic disk dispenser; antibiotic sensitivity disks: ampicillin 10 μg, amikacin
