Microbial Prevalence and Antimicrobial Sensitivity in Equine Endometritis in Field Conditions

Abstract

Endometritis is one of the main causes of infertility in mares. In the present study, 363 mares with a history of repetitive infertility, and positive endometrial cytology and/or vaginal discharge were included. An endometrial swab for microbiological purposes plus sensitivity test was obtained from each mare. A positive culture was obtained in 89% of mares. The main isolated genera were Staphylococcus (25.1%), Streptococcus (18.2%), Escherichia (17.3%) and Pseudomonas (12.1%). With regard to species, the most isolated microorganism was Escherichia coli (17.3%), Staphylococcus spp. (15.6%) and Streptococcus spp. (13.5%9). Sensitivity tests showed that the most efficient antimicrobial was amikacin (57.3% of cultures), followed by cefoxitin (48.6%) and gentamicin (48.3%). When sensitivity test was analyzed in terms of Gram+ and Gram– bacteria, Gram+ were highly resistant to cephaloridine (77.3% of cultures), apramycin (70.8%) and penicillin (62.3%), whereas Gram– were highly resistant to penicillin (85.8%), followed by cephaloridine (78.9%). In conclusion, the present study shows the most prevalent microorganisms isolated from equine endometritis, which were found to be resistant to β-lactam antimicrobials. Likewise, these results highlight the significance of performing microbiological analyses as well as sensitivity tests prior to applying an antimicrobial therapy.

Antimicrobial Susceptibility of Bacterial Isolates from Donkey Uterine Infections, 2018–2021

“…For Gram-negative bacteria, amikacin (98%) and cefoxitin were highly effective. The results agree with those reported previously [24]. Considering the absolute predominance of Gram-negative bacteria among pathogens in this study, we cautiously recommend these drugs for the clinical management of endometritis in donkeys.…”

“…were the most common pathogenic bacterial species in this study. The frequency of E. coli being isolated was consistent with previous results (27.9-30%) in mares [21][22][23], but was a little higher than some others (17.3-19.3%) [17,24]. E. coli, along with P. aeruginosa and K. pneumoniae, have been regarded as biofilm-producing microorganisms in equine endometritis [33][34][35].…”

“…Although the use of gentamicin is still recommended, an increasing resistance to gentamicin, due to empirical treatment without the identification of antimicrobial susceptibility, should be noted. Our results for TMPS (78%) were similar to those reported with mares in Sweden (2003) and Italy (2008) [17,19], but higher than those in other European and American countries over the past ten years [16,21,24]. The often-empirical use of gentamicin and TMPS in the treatment of endometritis may lead to increasing resistance of equine endometritis pathogens to them [22].…”

“…Larger scale epidemiological investigations should be conducted in the future to increase the number of donkeys. Different geographical locations, the population of animals included, and the antimicrobials used before have been suggested to be the general causes [21,24].…”

“…In such cases, treatments often have a lower than desired efficacy. Several studies have been reported on horses confirming that pathogenic species and their antimicrobial susceptibility patterns vary greatly over time and across geographic locations [19,[21][22][23][24].…”