Direct endoscopic lavage and biopsy sampling and evaluation of uterine microflora in various stages of the canine estrous cycle

Document Type: Short Communication


1 Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran

2 Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran


The microbial population of the uterus fluctuates during the estrous cycle. Microflora of uterus may affect the establishment and maintenance of pregnancy in bitches. The endoscopic samples obtained from the vagina and uterus of 20 female adult mixed‑breed dogs. The uterine lavage samples were prepared for cytology, bacterial (aerobic and anaerobic) and fungal cultures. Uterine tissue samples were evaluated for the presence of E. coli by the polymerase chain reaction. The pure growth of bacteria was observed in seven plates out of the nineteen cultured samples (36.84%) and five Gram-negative and two Gram-positive bacteria were detected. The highest number of isolated bacteria was related to the samples of the diestrus and anestrus stages of the estrous cycle, while the lowest number of bacteria was observed in the samples of the estrous stage. Moreover, Citrobacter spp. was the most frequent group of isolated bacteria. The neutrophils were detected in the cytology of uterine samples. The fungi growth was observed in three uterine samples. Cladosporium and Penicillium isolated from the samples were related to the estrus stage, and yeast was grown in diestrus samples. 16srRNA gene existed in all of the estrous uterine samples in which the bacterial culture was negative. However, the presence of this gene was proven in two samples (33.30%) of negative bacterial culture samples from the diestrus and anestrus stages. In conclusion, the normal bitches’ uteri were infected with various bacteria in estrus, diestrus and anestrus stages of the estrous cycle, and it could coincide with the fungi infection.


  1. Prescott JF, Hanna WJB, Reid-Smith R, et al. Anti-microbial drug use and resistance in dogs. Can Vet J 2002; 43(2):107-116.
  2. Laurusevičius SA, Šiugždaitė J, Žilinskas H. Correlation between different sexual cycle stages and vaginal bacterial flora in bitches of different breeds. Vet Zootech-Lith 2008; 41(63):76-79.
  3. Kustritz MVR. Collection of tissue and culture samples from the canine reproductive tract. Theriogenology 2006; 66(3):567-574.
  4. Baba E, Hata H, Fukata T, et al. Vaginal and uterine microflora of adult dogs. Am J Vet Res 1983; 44(4):606-609.
  5. Watts JR, Wright PJ, Lee CS, et al. New techniques using transcervical uterine cannulation for the diagnosis of uterine disorders in bitches. J Reprod Fertil Suppl 1997; 51:283-293.
  6. Christensen BW, Schlafer DH, Agnew DW, et al. Diagnostic value of transcervical endometrial biopsies in domestic dogs compared with full-thickness uterine sections. Reprod Domest Anim 2012; 47:342-346.
  7. Markey B, Leonard F, Archambault M, et al. Clinical veterinary microbiology. 2nd ed. Edinburgh, UK: Elsevier Health Sciences 2013; 9-49.
  8. Schultheiss PC, Jones RL, Kesel ML, et al. Normal bacterial flora in canine and feline uteri. J Vet Diagn Inves 1999; 11(6):560-562.
  9. Watts J, Wright P, Whithear K. Uterine, cervical and vaginal microflora of the normal bitch throughout the reproductive cycle. J Small Anim Pract 1996; 37(2):54-60.
  10. Olson P, Mather E. Canine vaginal and uterine bacterial flora. J Am Vet Med Assoc 1978; 172(6):708-711.
  11. Gunay U, Onat K, Gunay A, et al. Vaginal, cervical and uterine bacterial flora at the different stages of the reproductive cycle in ovariohysterectomized bitches. J Anim Vet Adv 2010; 9(3):478-481.
  12. Holzmann A, Laber G, Walzl H. Experimentally induced mycoplasmal infection in the genital tract of the female dog. Theriogenology 1979; 12(6):355-370.
  13. Watts JR, Wright PJ, Lee CS. Endometrial cytology of the normal bitch throughout the reproductive cycle. J Small Anim Pract 1998; 39(1):2-9.
  14. Mogheiseh A, Derakhshandeh A, Batebi E, et al. Co-relation of estrous cycle phases with uterine bacterial and fungal flora in non-pregnant female laboratory rabbits. Iran J Vet Res 2017; 18(2):128-133.
  15. Shokri H, Khosravi A, Sharifzadeh A, et al. Isolation and identification of yeast flora from genital tract in healthy female camels (Camelus dromedarius). Vet Microbiol 2010; 144(1):183-186.
  16. Hirsh DC, Wiger N. The bacterial flora of the normal canine vagina compared with that of vaginal exudates. J Small Anim Pract 1977; 18(1):25-30.
  17. Osbaldiston G, Nuru S, Mosier J. Vaginal cytology and microflora of infertile bitches. J Am Anim Hosp Assoc 1972; 8:93-101.
  18. Sancak AA, Dhaliwal GK. DNA hybridization of Escherichia coli strains isolated from uteri and fecal samples of bitches with pyometra. Turk J Vet Anim Sci 2004; 28(5):857-863.