Studies on the bacteriology and pathology of bovine endometritis

Abstract

It has been aimed to present information on the bacterial flora of normal genital tracts, and bacteriology and pathology of endometritis in cows.1. survey of the bacterial flora of 100 normal non -pregnant and 31 normal pregnant genital tracts of dairy cows is reported. 45 per cent of non -pregnant and 32.2 per cent of pregnant genital tracts contained bacteria. The incidence of bacteria in the cervix uteri was 41 %; corpus uteri 9%; right uterine cornu 20%; left uterine cornu 9'/:.; and Fallopian tubes 2 %. These results indicate that under normal conditions bacteria traverse the cervix up the uterus and a healthy cervix acts as a barrier against infection.2. There was similarity between the bacterial flora of the non- pregnant and pregnant uteri; and also between that of the uterochorionic space and amniotic fluid.3. iiicrococci (15,) were the commonest bacteria in the genital tracts of non -pregnant cows, the next in order were corynebacteria (16%); staphylococci (15;;:x); coliform bacilli (y-); streptococci (W; Gram positive aerobic sporing rods (3:-); sarcinae (1%) and hlcaligenes faecalis (1%).4. Neither Corynebacterium pyogenes nor Brucella abortus nor mastitis groups of streptococci (Lancefie group B. and Minett's groups 11 and 111) were isolate from the normal genital tracts.5. One hundred abnormal genital tracts were examined for their bacterial contents and pathological changes; 93 had endometritis associated ,viith cervicit (32%) and salpingitis (25.3%), five primary cervicitis and two salpingitis only.6. The bacterial flora of abnormal genital tract differed significantly from that of normal tracts. Corynebacteria were the largest group (51%); the next in order were staphylococci (33%), coliform bacilli (14%, streptococci (12%), micrococci (10%), Klebsiella oneumoniae (4%), Proteus vulgaris (3%) Mycobacteriumtuberculosis (2%), Bacillus mesentericus (2%) and Pseudomonas aeruginosa (1%).7. The folloing bacteria were isolated from the only abnormal genital tracts)- Corynebacterium pyogenes, Corynebacterium equi, Staphylococcus aureus (with one exception where it was isolated from a normal cervix) Klebsiella oneumoniae, streptococci of Lancefield's groups C. and G., Proteus vulgaris, Pseudomonäs aeruginosa and Mycobacterium tuberculosis. Further, the incidence of Staphylococcus albus was increased to 25% in the pathological tracts as compared with 9.1% in the normal, the respective figures for Escherichia coli were 14% and 7.6% and Corynebacterium bovis 5% and 1.5%.8. There was correlation between the type of endcmetritis and the bacteria present in the uteri. Staphylococci, «lebsiella pneumoniae, Proteus vularis, coliform bacilli, streptococci and Pseudomonas aeruo.in psa were associated with catarrhal endometritis, whereas Corynebacterium pyogenes, Corynebacterium bovis and Corynebacterium equi in pure or mixed cultures were found in suppurative endometritis.9. Corynebacterium nyogenes is considered the most important single factor in the causation of .suppurative endometritis since it was isolated from 86% of such cases. Staphylococci were mostly associated with catarrhal endometritis and isolated from 50% of such cases. A new variety of coryne- :bacterium has been isolated and described. Tentatively it has been designated Corynebacterium bovis var metritis.10. Trichomonas foetus was recorded in three cases of catarrhal endometritis. The cows from which these uteri were obtained belonged to three different farms in Ayrshire.11. a. Five main types of endometritis were distinguished according to the pathological changes present viz., catarrhal endometritis (34.4%); suppurat endometritis (38.7%); atrophic endometritis (12.9%); tuberculous endometritis (2.1%) and hyperplast is endometritis (11.8%).12. a. The lesions observed in diffrent cases of catarrhal endometritis were ,primarily those of catrrhal inflammation of endometrium with epithelial degeneration, s_quamous metaplasia and degeneration of glandular epithelium. These changes may be regarded as the though foetus result of infections of a mild character, in the case of staphylococci and Trichomonas the structural alterations were pronounced.b. In striking contrast to the above, suppurative endometritis was characterised by extensiv necrosis of endometrium including sloughing of cotyledons; and usually involved all layers of the uterine wall, periuterine structures and Fallopian tubes. Persistait corpus luteun was a constant feature of well established cases of pyometra. In the acute and chronic cases th damage to the functional structures of the uterus was so great that it is doubtful if they ever would have regained their normal function. In sub -acute cases the lesions were mainly confined to cotyledons. Since this sub -acute stage is not easily diagnosable clinically, bacteriological examination of uterine swabs is essential.c. The prominent structural changes in atrophic endometritis were extensive necrosis and atrophy mucosa, contraction of interstitial tissue and intimal thickening of the arterial walls. Such changes may be regarded as the late result of acute inflammation where there had been extensive destruction of the endometrium.d. Hyperplastic endometritis was characterised by hyperplasia of endometrium and its glands whose cystic dilatation was a prominent feature. It was invariably associated with cystic ovaries. This type of endometritis probably represents a hormonal disturbance, the cause of which remains ohscure.13. The pathogenicity of Corynebacterium oyogenes, Corynebacterium equi and Staphylococcus albus all isolated from bovine endometritis was tested upon ligated uterine cornua of guinea pigs. A study of the progress of the lesions at various stages of infection bowed that Corynebacterium pyogenes and Staphylococcus albus gave rise to typical lesions comparable to those met with in natural cases of endometritis in cows.Fifty-two photographs illustrating the normal and abnormal uteri are included.14. The pH of normal uterine fluid averaged 7.08; amniotic fluid 7.22; the pathological exudate in catarrhal endometritis averaged 7.50; suppurative endometritis 7.61; atrophic endometritis 7.48 and hyperplastic endometritis 7.01.15. The significance of endometritis in relation to bacteria, ovarian abnormalities and sterility is discussed.