Page 442 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Reproductive system: 2.1 The female reproductive tr act 417

VetBooks.ir speculum or manual vaginal examination (Fig. 2.16). should be considered as potentially pathogenic:
Use of a sterile double-guarded swab passed directly
beta-hemolytic streptococci; haemolytic Escherichia
into the uterine lumen is the best way of avoiding
types); Candida spp.; certain Staphylococcus spp.
commensal contamination. It is important that the coli; Pseudomonas spp.; Klebsiella spp. (certain capsule
perineum of the mare is washed and dried, and an
aseptic vaginal examination carried out either man- Uterine cytology
ually or by vaginoscopy. The collection of samples Uterine cytology is a simple but effective method
for cytological examination can be carried out at the of detecting signs of uterine inflammation, and
same time. Cultures are best taken in early oestrus complements uterine bacteriological sampling. The
since the cervix is relaxing, there are increased secre- presence of neutrophils in uterine cytological speci-
tions from the uterus and there is less risk of false mens indicates an active inflammatory process. The
results or introducing an infection. Swabs, however, sample should be collected in early to mid-oestrus
can be taken at any time. As the swab is dry, it should using the same basic technique as for uterine cul-
be either plated out immediately or transported in ture. Cytological samples can be obtained in two
a suitable transport medium. The swabs are plated different ways:
on blood agar and a selective gram-negative medium
(McConkey) and incubated at 37°C (98.6°F) both • A small-volume uterine flush: 60 ml of sterile
aerobically and microaerophilically. isotonic saline is flushed into the uterus and then
In general, pure cultures and heavy growths aspirated. This is then centrifuged and placed
are more likely to be significant than light mixed onto a slide.
growths, which are often contaminants. The inter- • A double-guarded swab or a swab taken through
pretation of culture results is helped by correlating a vaginal speculum, which is then ‘rolled’ onto a
them with the cytological and/or ultrasound find- microscope slide. The swab can also be used for
ings. For example, if the culture is positive (moderate endometrial culture if the slide is sterile.
to light growth) but the cytology results are negative
for inflammatory cells (particularly neutrophils), the The collected smears are stained (pre-stained
culture is likely to be a contaminant. Where cyto- slides may be used) using, for example, Diff-Quik
®
logical findings are persistently positive with nega- and examined for the presence of endometrial epi-
tive cultures, the cause of the inflammatory response thelial cells and polymorphonuclear neutrophils
should be explored further. The following bacte- (Fig. 2.18). It is also possible to have an indication
rial organisms, if cultured in significant numbers, as to whether the mare is anovulatory, transitional

2.18

Fig. 2.18 An endometrial smear
from an oestrous mare with large
numbers of polymorphonuclear
neutrophils present suggesting
the presence of inflammation and
possible infection. (Photo courtesy
Graham Munroe).