Use of a low-volume uterine flush for diagnosing endometritis in chronically infertile mares

Inflammatory markers for differentiation of endometritis in the mare

BACKGROUND

Endometrial biopsy is required to diagnose mares with chronic endometritis and endometrial degenerative fibrosis. An increase in understanding of equine reproductive immunology could be utilised to create less-invasive, time-efficient diagnostic tools especially when evaluating mares for chronic endometritis.

OBJECTIVES

To evaluate inflammatory cytokine and chemokine concentrations in uterine fluid samples collected by low-volume lavage (LVL) as a potential screening diagnostic biomarker for endometritis.

STUDY DESIGN

Prospective cross-sectional clinical study.

METHODS

Forty-six mares underwent a LVL and subsequently endometrial biopsy. Mares were split in three groups: healthy, acute endometritis, and chronic endometrial fibrosis (CEF) based on cytological and histological evaluation. A fluorescent bead-based multiplex assay for IFN-γ, IFN-α, IL-1β, IL-4, IL-10, IL-17, sCD14, TNF-α, CCL2, CCL3, CCL5 and CCL11 were carried out on the LVL fluid. The endometrial biopsy was utilised for histology and qPCR of IFN-γ, IL-1β, IL-6, IL-8, IL-17, TNF-α, CCL2 and CCL3 genes. Statistical analyses examined differences in inflammatory markers and predictive modelling for diseased endometrium.

RESULTS

Secreted concentrations of IFN-γ were lower in LVL fluid from reproductively healthy mares compared with acute endometritis (p = 0.04) and CEF (p = 0.006). Additionally, IL-17, IL-10, IL-1β, TNF-α, CCL2, CCL3, CCL5 and CCL11 were significantly increased (p ≤ 0.04) in LVL from CEF mares compared with healthy mares. Mares with CCL2 concentrations ≥550 pg/mL (14/14) had 100% probability of having CEF and/or acute endometritis. Healthy mares had lower relative abundance of IL-17 mRNA compared with mares in CEF group [median (interquartile rage) = 14.76 (13.3, 15.3) and 12.4 (10.54, 13.81)], respectively (p = 0.02).

MAIN LIMITATIONS

Limited sample size: larger numbers of mares with and without endometritis are required and reference intervals in LVL samples have to be established.

CONCLUSIONS

Inflammatory chemokines and cytokines concentrations differed between healthy mares and mares with acute endometritis or CEF in LVL.

Metagenomic analysis unravels novel taxonomic differences in the uterine microbiome between healthy mares and mares with endometritis

BACKGROUND

The application of high throughput technologies has enabled unravelling of unique differences between healthy mares and mares with endometritis at transcriptomic and proteomic levels. However, differences in the uterine microbiome are yet to be investigated.

OBJECTIVES

The present study was aimed at evaluating the differences in uterine microbiome between healthy mares and mares with endometritis.

METHODS

Low-volume lavage (LVL) samples were collected from the uterus of 30 mares classified into healthy (n = 15) and endometritis (n = 15) based on their reproductive history, intrauterine fluid accumulation, gross appearance of LVL samples, endometrial cytology and bacterial culture. The samples were subjected to 16S rRNA sequencing.

RESULTS

Notable differences in the uterine microbiome were observed between healthy mares and mares with endometritis at various taxonomic levels. In healthy mares, the most abundant phylum, class, order and family were Firmicutes, Bacilli, Bacillales and Paenibacillaceae, respectively. In contrast, the most abundant corresponding taxonomic levels in mares with endometritis were Proteobacteria, Gammaproteobacteria, Enterobacterales and Enterobacteriaceae, respectively. At the genus level, Brevibacillus and Paenibacillus were more abundant in healthy mares, whereas Escherichia, Salmonella and Klebsiella were more abundant in mares with endometritis. In healthy mares, Brevibacillus brevis was the most abundant species, followed by Brevibacillus choshinensis and Paenibacillus sp JDR-2. However, in mares with endometritis, Escherichia coli was the most abundant species, followed by Salmonella enterica and Klebsiella pneumoniae.

CONCLUSIONS

These results confirmed the previously reported presence of a uterine microbiome in healthy mares and helped unravel some alterations that occur in mares with endometritis. The findings can potentially help formulate new approaches to prevent or treat equine endometritis.

Use of cytobrush for bacteriological and cytological diagnosis of endometritis in mares

Background and Aim

A combined microbial and cytological examination of uterine samples is the main diagnostic method for endometritis in mares. This study aimed to describe a procedure for using the same uterine cytobrush (CB) for both bacteriological and cytological evaluation.

Material and Methods

The procedure consists of rolling the CB onto a sterilized glass slide immediately after collection and before the transfer into a sterile saline solution. In Experiment 1, a comparison between bacteriological results of the cotton swab (CS) and CB or pellet was made in 10 mares; in Experiment 2, bacteriological and cytological results were compared between different processing methods of CB in 28 mares; in other 6 mares, a CB was processed for cytology only, to investigate the reasons for the low cellularity of the pellet.

Results

The agreement between culture results from the CB and CS was evaluated, and a comparison between the cytological data obtained by different processing methods of CB was performed. The perfect agreement between the CB and CS microbiological results was found. The described procedure enables useful diagnostic smears for cytology. Moreover, the seeding of both the tip of CB and the saline solution used for the transport produced accurate bacteriological results.

Conclusion

The protocol described in this study for the use of CB for both cytological and bacteriological analysis could be used for the diagnosis of endometritis. To maximize diagnostic sample quality, cytology slides must be prepared with meticulous care in the field to preserve cellular integrity and minimize artifacts.

Success of different therapies for bacterial endometritis in stud farm practice

Bacterial endometritis is a major problem in equine reproduction usually treated with antibiotics, however reports of success rates are scarce. This study collected data from mares diagnosed with intrauterine bacterial growth and compared the outcome of different therapies for bacterial endometritis in German stud farm practice. Data on mares with positive uterine culture results were collected retrospectively in veterinary practices (n = 5; 2018-2022). Information relating to 30 factors (mare, diagnostics, therapy, pregnancy rate) of bacterial endometritis cases (n = 772) were recorded and analyzed. Possible effects on treatment success (positive pregnancy result in the first cycle after treatment) were tested by binomial logistic regression. In most cases β-hemolytic streptococci were detected (n = 707). Treatments for the endometritis included trimethoprim-sulfonamides (n = 409), procaine-penicillin (n = 227), marbofloxacin (n = 53) or no antibiotics (n = 59) and most antibiotics were administered systemically (n = 711) rather than locally (n = 23). Uterine lavage was reported in 49 % of mares. Uterotonic drugs were administered in 42.2 % of mares. Breeding programs included artificial insemination (AI) with chilled semen (n = 667), AI with frozen semen (n = 169), transfer of fresh (n = 112) or cryopreserved (n = 27) embryos and natural cover (n = 27). In the first cycle after treatment, the pregnancy rate was 47 % and it rose to 69 % by end of the season. Treatment success was affected by duration of antibiotic treatment, veterinary practice, and presence of clinical signs. In conclusion, reported treatment practices in German stud farm practice resulted in acceptable pregnancy results and the multiple binomial logistic regression approach identified factors affecting the pregnancy outcome in this dataset.

Effect of Sampling Method on Detection of the Equine Uterine Microbiome during Estrus

Bacterial endometritis is among the most common causes of subfertility in mares. It has a major economic impact on the equine breeding industry. The sensitivity of detecting uterine microbes using culture-based methods, irrespective of the sample collection method, double-guarded endometrial swab, endometrial biopsy, or uterine low-volume lavage (LVL), is low. Therefore, equine bacterial endometritis often goes undiagnosed. Sixteen individual mares were enrolled, and an endometrial sample was obtained using each method from all mares. After trimming, quality control and decontamination, 3824 amplicon sequence variants were detected in the dataset. We found using 16S rRNA sequencing that the equine uterus harbors a distinct resident microbiome during estrus. All three sampling methods used yielded similar results in composition as well as relative abundance at phyla (Proteobacteria, Firmicutes, and Bacteroidota) and genus (Klebsiella, Mycoplasma, and Aeromonas) levels. A significant difference was found in alpha diversity (Chao1) between LVL and endometrial biopsy, suggesting that LVL is superior at detecting the low-abundant (rare) taxa. These new data could pave the way for innovative treatment methods for endometrial disease and subfertility in mares. This, in turn, could lead to more judicious antimicrobial use in the equine breeding industry.

Antimicrobial Resistance and Extended-Spectrum Beta-Lactamase Genes in Enterobacterales, Pseudomonas and Acinetobacter Isolates from the Uterus of Healthy Mares

Antibiotic-resistant bacteria are a growing concern for human and animal health. The objective of this study was to determine the antimicrobial resistance and extended-spectrum beta-lactamase genes in Enterobacterales, Pseudomonas spp. and Acinetobacter spp. isolates from the uterus of healthy mares. For this purpose, 21 mares were swabbed for samples, which were later seeded on blood agar and MacConkey agar. The isolates were identified using MALDI-TOF and the antimicrobial susceptibility test was performed using the Kirby-Bauer technique. To characterize the resistance genes, a polymerase chain reaction (PCR) scheme was performed. Of the isolates identified as Gram-negative, 68.8% were Enterobacterales, represented by E. coli, Enterobacter cloacae, Citrobacter spp., and Klebsiella pneumoniae; 28.1% belonged to the genus Acinetobacter spp.; and 3.1% to Pseudomonas aeruginosa. A 9.3% of the isolates were multidrug-resistant (MDR), presenting resistance to antibiotics from three different classes, while 18.8% presented resistance to two or more classes of different antibiotics. The diversity of three genes that code for ESBL (blaTEM, blaCTX-M and blaSHV) was detected in 12.5% of the strains. The most frequent was blaSHV, while blaTEM and blaCTX-M were present in Citrobacter spp. and Klebsiella pneumoniae. These results are an alarm call for veterinarians and their environment and suggest taking measures to prevent the spread of these microorganisms.

RNA in situ hybridization of Escherichia coli in equine endometrial biopsies

Endometritis is one of the major causes of infertility in mares. Escherichia coli and β-haemolytic streptococci are among the bacterial species most frequently isolated from the equine uterus. Some bacteria such as β-hemolytic streptococci, can persist in dormant forms and cause prolonged, latent or recurrent infections. Dormant bacteria may be present despite negative bacterial cultures, and they are resistant to antimicrobial treatment due to their resting metabolic state. The purpose of this study was to study formalin-fixed paraffin-embedded equine endometrial biopsies for the presence and localization of E. coli-bacteria, with a chromogenic RNAscope^®-method for detection of E. coli-related 16S ribosomal RNA. Hematoxylin-eosin-stained endometrial biopsies were evaluated to determine the level of inflammation and degeneration. During estrus, samples were taken for endometrial culture and cytology with a double-guarded uterine swab. The samples included eight samples with moderate to severe endometrial inflammation detected in endometrial histopathology, and growth of E. coli in bacterial culture, six samples with moderate to severe endometrial inflammation but negative bacterial culture, and five samples with no endometrial pathology (grade I endometrial biopsy, negative endometrial culture and cytology) serving as controls. Positive and negative control probes were included in the RNA in situ hybridization, and results were confirmed with a fluorescence detection method (fluorescence in situ hybridization). Only unspecific signals of limited size and frequency of occurrence were detected in all samples, with random localization in the endometrium. No samples contained rod-shaped signals corresponding to bacterial findings. In conclusion, there was no evidence of bacterial invasion in the endometrium regardless of the inflammatory status of the biopsy or previous bacterial culture results. According to these findings on a small number of samples, invasion of E. coli is not a common finding in the lamina propria of mares, but these bacteria may also evade detection due to localized foci of infections, or supra-epithelial localization under the cover of biofilm. These bacteria and biofilm covering the epithelium may also be lost during formalin-fixation and processing.

Relationship between Clinical Uterine Findings, Therapy, and Fertility in the Mare

Persistent breeding-induced endometritis (PBIE) is a major cause of subfertility in horses and the susceptibility is increased by several factors. The aim of this study was to determine the effects of clinical uterine findings and PBIE therapies, respectively, on pregnancy rate in mares. The analysis included records from 220 mares (390 cycles) inseminated at an artificial insemination (AI) center in Switzerland. Gynecological examinations were performed repeatedly before and after AI to determine cervical tone, uterine edema, and intrauterine fluid accumulation. Pregnancy rate was lower (p < 0.001) in barren mares compared to mares of other reproductive status. A more flaccid cervix (p = 0.009) was observed at the time of ovulation in pregnant cycles, but there was no difference (p > 0.05) regarding uterine edema. Intrauterine fluid accumulation reduced pregnancy rate (p = 0.002). Oxytocin administration had beneficial effects on pregnancy rate (p = 0.015), especially for barren mares, while uterine lavage did not have any effect (p > 0.05). The results show that cervical tone and intrauterine fluid accumulation, but not its degree, are useful parameters for assessment of fertility in mares. Oxytocin treatment improved pregnancy rates in mares with PBIE while uterine lavage had a limited effect.

Characterization of Myeloperoxidase in the Healthy Equine Endometrium

Myeloperoxidase (MPO), as a marker of neutrophil activation, has been associated with equine endometritis. However, in absence of inflammation, MPO is constantly detected in the uterine lumen of estrous mares. The aim of this study was to characterize MPO in the uterus of mares under physiological conditions as a first step to better understand the role of this enzyme in equine reproduction. Total and active MPO concentrations were determined, by ELISA and SIEFED assay, respectively, in low-volume lavages from mares in estrus (n = 26), diestrus (n = 18) and anestrus (n = 8) in absence of endometritis. Immunohistochemical analysis was performed on 21 endometrial biopsies randomly selected: estrus (n = 11), diestrus (n = 6) and anestrus (n = 4). MPO, although mostly enzymatically inactive, was present in highly variable concentrations in uterine lavages in all studied phases, with elevated concentrations in estrus and anestrus, while in diestrus, concentrations were much lower. Intracytoplasmic immunoexpression of MPO was detected in the endometrial epithelial cells, neutrophils and glandular secretions. Maximal expression was observed during estrus in mid and basal glands with a predominant intracytoplasmic apical reinforcement. In diestrus, immunopositive glands were sporadic. In anestrus, only the luminal epithelium showed residual MPO immunostaining. These results confirm a constant presence of MPO in the uterine lumen of mares in absence of inflammation, probably as part of the uterine mucosal immune system, and suggest that endometrial cells are a source of uterine MPO under physiological cyclic conditions.

Isolated Bacteria from the Uteri of Camels with Different Reproductive Backgrounds: A Study on Sampling Methodology, Prevalence, and Clinical Significance

The objectives of this study were to comparatively identify the common bacterial isolates from the uteri of camels coming from different reproductive backgrounds after standardizing the sampling method and to investigate the association of clinically measurable parameters with uterine colonization by these isolates. The uterine samples from 856 dromedary camels yielded a total of 17 different bacterial species with a higher proportion of sub-fertile camel uteri being colonized by bacteria (66.6%) as compared to nulliparous, recently calved, and those with unknown reproductive history combined (44.2%; p < 0.05). Camels with body condition scoring < 3 and those with a consistently echogenic appearance of the uterine lumen by sonography were more likely to be positive on uterine culture, while the presence of pus in uterine discharge was not associated with the odds of bacterial isolation (p > 0.05). While certain strains were more likely to be obtained from the uteri of the sub-fertile group (p < 0.05), embryo transfer to camels with a positive uterine culture in the absence of other gross reproductive pathologies did not necessarily affect the overall pregnancy rate compared to recipients with a negative uterine culture (p > 0.05). In conclusion, a relatively high bacterial load can be identified from the uteri of both sub-fertile and normal dromedary camels, with a higher frequency among the former. The uterine ultrasonography and evaluation of the body condition score can help in identifying the camels in which uterus is contaminated by bacteria.

Comparison Between Gynecological Examination Methods and Sample Collection Techniques for the Diagnosis of Endometritis in Subfertile Mares

Endometritis is a relevant cause of subfertility in mares. However, the accurate diagnosis, essential for effective treatment, can be difficult due to the variability of results and interpretations resulting from different examination methods and sample collection techniques. The present work compared gynecological evaluation methods and sample collection techniques to diagnose endometritis in subfertile mares. Forty animals with a history of subfertility were selected for gynecological evaluation using clinical methodologies, such as perineal conformation, transrectal palpation and ultrasonography, vaginoscopy, and digital examination of the cervix. In addition, we performed laboratory analyses, including uterine microbiological culture and endometrial cytology and histology, of which the latter is the gold standard for the diagnosis of endometritis. Samples were collected for microbiological culture and endometrial cytological evaluations using three different techniques: a commercial cytobrush/swab collector, low-volume uterine flush, and a new tested technique, by flush the fragment resulting from the endometrial biopsy. Transrectal palpation and ultrasound showed the best results among clinical examinations. However, they were less efficient in laboratory tests of endometrial cytology and uterine microbiological culture, in which the latter showed the highest sensitivity and specificity for endometritis compared with endometrial histology. The use of multiple results from different methods has also proved to be an effective alternative for diagnosis. Among the techniques used to collect endometrial material for cytology and microbiological culture, the most effective and practical in this study was the commercial cytobrush/swab collector.

Endometrial and vaginal microbiome in donkeys with and without clinical endometritis

Endometrial and vaginal microbiomes are critical in the study of endometritis, which is an important cause of infertility in donkeys. Our objective was to investigate the difference of the endometrial and vaginal microbiomes between healthy donkey jennies (group C) and jennies with endometritis (group E). Endometrial and vaginal swab samples were collected, and the 16 s rRNA gene amplicon high-throughput sequencing technique was applied to identify the microbial composition in the samples. A similar microbial composition pattern was found between endometrial and vaginal samples, which indicated the impact of the vaginal microbiome on the endometrial microbial environment and health. There was a significant difference of endometrial and vaginal swab samples between the two groups. Ruminococcaceae and Lachnospiraceae were significantly more abundant in endometrial and vaginal microbiomes of group E than in group C. Their dominance was consistent with increased anaerobic bacterial taxa in the functional analysis, which might be associated with the pathogenesis of endometritis in donkeys. Sphingomonadaceae, a bacterial family reported in bovine semen, was statistically more abundant in endometrial microbiome of group E than in group C, which might suggest an association between high abundance of Sphingomonadaceae possibly due to uncleared semen and donkey endometritis. Our study revealed the composition of the vaginal and endometrial microbiomes in healthy and endometritis donkeys. These findings will provide more insights into the pathogenesis of donkey endometritis.

Bacteria isolated from equine uteri in The United Arab Emirates: A retrospective study

The United Arab Emirates (UAE) presents a unique environment in which to breed horses with a non-physiological breeding season coupled with high temperatures and humidity for much of the year. This study aimed to describe bacterial isolates from the uteri of mares in the UAE and compare them to those reported elsewhere in the world. Bacterial antibiotic resistance was also analysed to give a starting point for future monitoring. A total of 2022 swabs taken over 5 breeding seasons from the endometrium (n = 1350) or from uterine lavages (n = 672) were submitted for microbiological culture and antibiotic sensitivity testing. At 48h post inoculation 616/2022 (30.5%) of cultures showed microbial growth from which 690 isolates were identified. Most positive plates (548/616; 89%) grew one isolate; 68 cultures had two (62/616; 10.1%) or three (6/616; 1%) isolates. The most frequently isolated bacteria were β-haemolytic Streptococcus (36.5%; 252/690), E. coli (10.6%; 73/690), P. aeruginosa (10.1%; 70/690), K. pneumoniae (8.8%; 61/690) and Aeromonas hydrophila (4.1%; 28/690). The lowest level of antibiotic susceptibility for all isolates was shown by trimethoprim-sulphonamide (36.4%; 198/544), with amikacin showing the highest (76.1%; 271/356). A significant decrease in susceptibility to doxycycline, enrofloxacin and erythromycin, but a significant increase for amoxicillin with clavulanic acid, was seen for β-haemolytic Streptococcus. Decreasing susceptibility of trimethoprim-sulphonamide between two time periods was seen for E. coli. Compared to other studies UAE-based mares had a high incidence of P. aeruginosa and K. pneumoniae isolates, whereas E. coli was represented far less frequently as an isolate.

Fluorescence Spectroscopy for the Diagnosis of Endometritis in the Mare

By exploiting the PMN property to produce high quantities of oxygen peroxide to neutralize pathogens, the oxygen peroxide content of uterine cells was measured to diagnose endometritis. After preliminary in vitro studies in which endometrial cells from slaughtered mares were mixed with leukocytes from peripheral blood, endometrial samples were collected by uterine flushing from mares before insemination. Staining endometrial cells with H2DCF-DA was combined with hydroethidine to normalize the fluorescence intensity with the cellular content of the sample. Stained cell smears were assumed as the gold standard of endometritis, and based on this assay, the samples were considered positive (C+) and negative (C−) for endometritis. The amount and the turbidity of fluid recovered by uterine flushing were significantly (p < 0.01) higher in C+ than in C−. Moreover, the oxygen peroxide content of the endometrial cells was significantly higher in the C+ than in the C− group (6.31 ± 1.92 vs. 3.12 ± 1.26, p = 0.001). Using the value of 4.4 as the cutoff level of this fluorescence cytology assay, it was found that only one C− sample exceeded the cutoff level (false positives = 7.7%) while three C+ samples showed values below the cutoff level (false negative = 11.5%).

Moderate differences in plasma leptin in mares have no effect on either the amino acid or the fatty acid composition of the uterine fluid

Female mammalian reproductive functions are closely linked to body condition and metabolic status. Energy homeostasis is regulated by endocrine hormones such as insulin, IGF-I, leptin and adiponectin via the hypothalamic-pituitary-adrenal axis. These metabolic hormones and their receptors are also expressed in reproductive tissues and the embryo. We investigated the relationship between circulating leptin and the fatty acid (FA) and amino acid (AA) composition of the equine uterine fluid (UF) and peripheral blood plasma (BP) by using a mass spectrometry-based approach. UF and BP were collected from ten broodmares on days 6 and 7 post ovulation, respectively. The mares were retrospectively assigned to two groups according to their BP leptin concentrations (high leptin (> 1.6 ng/ml) versus low leptin (<0.8 ng/ml)). Specific AA and FA compositions for BP and UF were found with different levels of respective metabolite abundances. The main FAs in BP were stearic, palmitic and linoleic acid. In UF, the three most abundant FAs were eicosapentaenoic, arachidonic and stearic acid. The AA profile of BP was dominated by glycine, glutamine, serine and alanine, which were likewise among the highly abundant AAs in UF. In UF, glutamic acid had by far the highest concentration. Therefore, BP leptin concentration within a physiological range do not seem to affect the specific FA nor the AA composition of the UF. The composition of the UF may therefore be mediated by local rather than by peripheral metabolic hormones.

A comparative analysis of the intrauterine transcriptome in fertile and subfertile mares using cytobrush sampling

Background

Subfertility is a major problem in modern horse breeding. Especially, mares without clinical signs of reproductive diseases, without known uterine pathogens and no evidence of inflammation but not becoming pregnant after several breeding attempts are challenging for veterinarians. To obtain new insights into the cause of these fertility problems and aiming at improving diagnosis of subfertile mares, a comparative analysis of the intrauterine transcriptome in subfertile and fertile mares was performed. Uterine cytobrush samples were collected during estrus from 57 mares without clinical signs of uterine diseases. RNA was extracted from the cytobrush samples and samples from 11 selected subfertile and 11 fertile mares were used for Illumina RNA-sequencing.

Results

The cytobrush sampling was a suitable technique to isolate enough RNA of high quality for transcriptome analysis. Comparing subfertile and fertile mares, 114 differentially expressed genes (FDR = 10%) were identified. Metascape enrichment analysis revealed that genes with lower mRNA levels in subfertile mares were related to ‘extracellular matrix (ECM)’, ‘ECM-receptor interaction’, ‘focal adhesion’, ‘immune response’ and ‘cytosolic calcium ion concentration’, while DEGs with higher levels in subfertile mares were enriched for ‘monocarboxyl acid transmembrane transport activity’ and ‘protein targeting’.

Conclusion

Our study revealed significant differences in the uterine transcriptome between fertile and subfertile mares and provides leads for potential uterine molecular biomarkers of subfertility in the mare.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07701-3.

Analysis of the uterine flush fluid proteome of healthy mares and mares with endometritis or fibrotic endometrial degeneration

The objective of this study was to evaluate the differences in the uterine flush fluid proteome between healthy mares and mares with endometritis or fibrotic endometrial degeneration (FED). Uterine flush fluid samples were collected from healthy mares (n=8; oestrus n=5 and dioestrus n=3) and mares with endometritis (n=23; oestrus n=14 and dioestrus n=9) or FED (n=7; oestrus n=6 and dioestrus n=1). Proteomic analysis was performed using label-free liquid chromatography-tandem mass spectrometry. Of 216 proteins identified during oestrus, 127 were common to all three groups, one protein was exclusively detected in healthy mares, 47 proteins were exclusively detected in mares with endometritis and four proteins were exclusively detected in mares with FED. Of 188 proteins identified during dioestrus, 113 proteins were common between healthy mares and mares with endometritis, eight proteins were exclusively detected in healthy mares and 67 proteins were exclusively detected in mares with endometritis. Quantitative analysis revealed a subset of proteins differing in abundance between the three groups during oestrus and between healthy mares and mares with endometritis during dioestrus. These results provide a springboard for evaluation of specific proteins as biomarkers of uterine health and disease and for investigation of their roles in the establishment and maintenance of pregnancy.

Changes in the Secretion of Anti-Inflammatory Cytokines and Acute-Phase Proteins in the Uterus after Artificial Insemination in the Mare

Simple Summary

Semen deposition into the uterus during mating or artificial insemination induces a rapid inflammatory response, and, in susceptible mares, persistent endometritis can develop. Cytokines are mediators involved in the regulation of the inflammatory process, and acute phase proteins are the most sensitive indicators of the inflammatory process. Therefore, the aim of this research was to determine the secretion of anti-inflammatory cytokines and acute-phase proteins in the uterus before and after artificial insemination in the mare. The obtained results indicate that the status of the mare before artificial insemination has little effect on the response measured shortly after artificial insemination. The presence of intrauterine fluid during estrus is not connected with the inflammation parameters investigated in this study at 7 h post artificial insemination. Detailed examination of the mare’s reproductive tract before and after artificial insemination guarantees high fertility.

Abstract

The objective of the study was to evaluate the concentrations of interleukin-1 receptor antagonist (IL-1RA), interleukin-10 (IL-10), serum amyloid A (SAA) and haptoglobin (Hp) in uterine lavage fluid before and after artificial insemination (AI). Based on ultrasound examination, mares were divided into: Group 1 (n = 9), no fluid was detected in the uterus during estrus and 7 h after AI; Group 2 (n = 8), no fluid was detected in the uterus during estrus but 7 h after AI fluid was detected in the uterus; Group 3 (n = 8), fluid was detected in the uterus during estrus and also 7 h after AI. In all groups of mares, a significant increase in polymorphonuclear cells (PMN) and a significant increase in IL-1RA and SAA were recorded 7 h after AI. The obtained results show that, regardless of the status of the mare before AI, the endometrial response characterized by PMN influx, and SAA, Hp, IL-1RA and IL-10 production, is similar. The presence of intrauterine fluid during estrus is not connected with PMN influx but can impact uterine IL-1RA production at this time.

Histopathological and cytological analyses of endometrium in water buffaloes (Bubalus bubalis) to detect estrus and endometritis

This study aimed to determine cytological, histopathological and cytomorphometrical characteristics of endometrium in healthy and endometritic uterus in the water buffalo. Fifty eight non-pregnant reproductive systems were collected from slaughterhouse. Efficiency of three methods of sampling including cotton swab, smear, and aspiration were compared for cytologic study. Concurrent histopathologic examination revealed endometritis in 38 uteri including 8 (21.00%) with mild endometritis, 7 (18.42%) with moderate endometritis, 6 (15.90%) with severe endometritis and 17 (44.73%) with chronic endometritis. Cyto-morphometrical results showed significant relationship between diameter and area of epithelial nuclei with phases of estrus cycle. Neutrophil and lymphocytes densities in swab and aspiration samples were significantly higher in severe endometritis than normal and chronic endometritis samples. Similarly, lymphocytes density in smear and aspiration methods was significant between normal and moderates, and also severe and chronic endometritis. Cytomorphometric analysis of epithelial nuclei characteristics (diameter and area) in buffalo were performed for the first time and it could be valuable to identify estrus cycle in this species. Aspiration had the most efficiency to identify endometritis in comparison with other methods.

Diagnostic and Treatment Practices of Equine Endometritis-A Questionnaire

Endometritis is a major cause for impaired fertility in mares. The objectives of this study were to collect information on diagnostic and treatment practices performed by veterinarians and to investigate possible effects of professional experience, caseload, and geographical location on the practitioners' management of endometritis cases. For this purpose, equine practitioners (n = 680) were asked to fill out an online survey (34 questions). The online survey yielded 117 responses by veterinarians practicing in all parts of Germany. Most respondents came from Lower Saxony and managed <20 mares per year. For the diagnosis of chronic infectious endometritis, uterine sampling for microbiological examination was performed manually with a swab by the majority of practitioners whereas only few used the speculum technique. The incidence of antibiotic resistant pathogens was reported to be <5% by almost all respondents. Most practitioners relied on systemic antibiotic treatment with trimethoprim-sulfadiazine. Only occasionally veterinarians used intrauterine antibiotic therapy. Uterine lavages were performed routinely by almost half of the respondents in case of positive uterine cultures, mostly with 0.9% saline solution. Irritant solutions (e.g., iodine, chlorhexidine, kerosene) were used less often. Collection of an endometrial culture after completion of the treatment was common practice. While only a very limited association of the geographical location of practitioner (e.g., on selection of mares for endometrial culture, p < 0.05) was observed, the number of managed mares affected the answers notably (e.g., for use of irritating intrauterine treatment, p < 0.05). The management of persistent breeding induced endometritis (PBIE) was influenced by the number of managed mares (e.g., for use of oxytocin, p < 0.05) and 29.6% of respondents administered antibiotics as part of their PBIE management. In summary, treatment strategies in the field vary considerably and include also non-evidence-based methods, but most German practitioners apply the recommended suitable treatments. Following the guidelines for antibiotic usage, most veterinarians administer antibiotics dependent on endometrial culture results but do not use cytology, low-volume lavage, or biopsy routinely. Antibiotic resistant uterine pathogens are reported to be isolated infrequently and equine practitioners prefer systemic to local antibiotic treatment of endometritis.

Detection of bacterial populations colonizing the genital tracts of jennies and their changes during the oestrous cycle

The aim of this study was to help improve the management of assisted reproduction of donkeys and to extend the existing information on the fertility of donkeys by qualitative and quantitative assessment of bacterial contamination of the jennies’ genital tract in connection with the perineum formation and oestrous cycle phases. Ten female donkeys were included in the study and were repeatedly rectally palpated and sonographically examined during the oestrous cycle. Samples were taken from the fossa clitoridis and around the cervix for microbiological examination. Each jenny was sampled twice, always at different stages of the cycle, both in the oestrus and in the dioestrus. In addition, samples from the endometrium were taken in oestrus for both microbiological and cytological examination. After collection, the samples were examined in a microbiological laboratory. There were 62 different species of microorganisms found belonging to 19 different bacterial genera. The presence of agents of mares’ infectious metritis Taylorella equigenitalis was not found in any of the samples. The outcome of our study is an initial mapping of the microbial colonization of the endometrium and the genital tract in jennies with correct formation of the perineal region. The hypothesis that the level of bacterial contamination was related to the oestrous cycle was not confirmed. The practical significance of the study lies mainly in the description of the composition, amount and changes of microbiota in healthy individuals during their oestrous cycle, which allows the evaluation of the risk of developing infection during the active oestrous cycle in connection with mating.

Endometrial Cytology During the Different Phases of the Estrous Cycle in Jennies: New Evidences

Since in the mare and other animal species such as bitches and cats, the endometrial cell pattern varies depending on the phase of the estrous cycle, the aim of this study was to describe and quantify the endometrial cytological (EC) findings in cycling jennies. EC of eight nonpregnant jennies by cytobrush (CB) at diestrus (day 1 and day 14) and estrous (day 21) were evaluated. All slides were stained with Wright´s stain and microscopically examined at both 400× and 1000× magnification. Seven high-power fields (400×) were assessed in each smear and the endometrial epithelial cells and neutrophils (PMNs) were counted. Endometrial epithelial cells were classified as intact, distorted or fragmented and, on the basis of the presence of dense groups, in monolayer or single clusters. Cytoplasmic characteristics, such as vacuolation or streaming and size, form, position of nuclear characteristics, including karyorrhexis, were recorded. Background aspect, as clear, proteinaceous, or debris, was also considered. In general, sampling by CB provided a yield of cells and clumped endometrial epithelial cells in many smears, being more abundant in estrus than early and late diestrus. Individual endometrial epithelial cells, during estrous, presented a columnar morphology, ciliated or not ciliated and basal nuclei. During diestrus phase, endometrial epithelial cells presented a more cuboidal ciliated or not ciliated morphology. Moderate amount of proteinacious material and red blood cells (RBC) was also observed. Non variation in the percentage of PMNs during diestrus was obtained, but lower and segmented PMNs in CB smears were shown in estrous. This study provides new insights on the physiological changes of endometrial epithelial cells in cycling jennies during the estrus cycle. The CB technique represents a suitable and adequate method for endometrial evaluation, taking into account cytological and/or cytopathological purposes also in jennies.

The advantages of using cytospins of uterine lavage fluid for the diagnosis of equine endometritis

Uterine lavage (UL) is a routine diagnostic procedure for endometritis. In UL the fluid is centrifuged and the sediment smeared. Samples prepared in cytocentrifuges, the so-called "cytospins", are useful for evaluating cells in fluids, but never been used in UL. The aim of this study was to assess the usefulness of cytospins after UL, comparing automatic versus manual cytocentrifuges, and to determine their value for the diagnosis of endometritis. The study was divided in two parts. Firstly, UL was performed in 16 mares and a small part of the retrieved fluid was cytocentrifuged in an automatic (PreCyto) and manual (PreMan) cytocentrifuge, whereas the remaining fluid was centrifuged. After that, the sediment was divided into three quotas. One quota was smeared, one was processed in an automatic cytocentrifuge (PostCyto) and the last quota was cytospinned in a manual apparatus (PostMan). Cytospins obtained were scored for cellularity, cell preservation, presence of inflammatory cells, bacteria and contaminants; results were compared with sediment smears. Secondly in this study, the best cytospin method was compared with sediment smears in another group of 13 mares, which had endometrial biopsy after UL. Agreement between sediment smears and cytospins was poor to moderate. Compared to sediment smears, cytospins were more cellular, with better morphological details. Urine crystals and fecal contamination were detected more often in cytospins (especially PostCyto and PostMan). No differences in the percentage of inflammatory or epithelial cells existed. PostMan was considered the best method to evaluate UL fluid and it had higher sensitivity (80%), compared with sediment smears (60%), for diagnosing endometritis. Cytocentrifugation offers significant advantages over sediment smears and the manual cytocentrifuge is well suited for horse stable conditions.

Diagnostic evaluation of subclinical endometritis in dromedary camels

The objective of the present study was to evaluate the efficacy of various diagnostic methods and to estimate the prevalence of bacterial pathogens associated with subclinical endometritis (SCE) in dromedary camels. During two consecutive breeding seasons, a total of 2122 infertile female dromedaries were assigned to this study and suspected cases of SCE were identified using the established criteria which included failure to conceive after three or more consecutive matings with a fertile male, a clinically healthy genital system, no observable vaginal discharge, and normal sexual behavior. Manual vaginal examination, Metricheck, bacteriological examination using endometrial swabbing, and hemogram assessments were conducted and there were comparisons of results to when there was cytological examination using the Cytobrush technique as the gold standard. The threshold value for positive cases of SCE was set at ≥ 5% polymorphnuclear cells in the cytological samples. Subclinical endometritis was diagnosed in 211 9.94 %) of the total infertility cases. Endometrial swabbing was a more sensitive and specific technique for diagnoses compared with the other methods. Bacillus sp., Staphylococcus sp., and Candida albicans were the most commonly isolated microorganisms. Hemogram testing and rectal and ultrasonographic examinations were not effective for the diagnosis of SCE. It was concluded that, compared with other diagnostic tests, bacteriological examination is more sensitive and specific for the detection of SCE in dromedaries.

Persistent Breeding-Induced Endometritis in Mares - a Multifaceted Challenge: From Clinical Aspects to Immunopathogenesis and Pathobiology

Post-breeding endometritis (i.e., inflammation/infection of the endometrium), is a physiological reaction taking place in the endometrium of mares within 48 hours post-breeding, aimed to clear seminal plasma, excess sperm, microorganisms, and debris from the uterine lumen in preparation for the arrival of an embryo. Mares are classified as susceptible or resistant to persistent breeding-induced endometritis (PBIE) based on their ability to clear this inflammation/infection by 48 hours post-breeding. Mares susceptible to PBIE, or those with difficulty clearing infection/inflammation, have a deficient immune response and compromised physical mechanisms of defense against infection. Molecular pathways of the innate immune response known to be involved in PBIE are discussed herein. The role of the adaptive uterine immune response on PBIE remains to be elucidated in horses. Advances in the pathobiology of microbes involved in PBIE are also revised here. Traditional and non-traditional therapeutic modalities for endometritis are contrasted and described in the context of clinical and molecular aspects. In recent years, the lack of efficacy of traditional therapeutic modalities, alongside the ever-increasing incidence of antibiotic-resistant microorganisms, has enforced the development of non-traditional therapies. Novel biological products capable of modulating the endometrial inflammatory response are also discussed here as part of the non-traditional therapies for endometritis.

Temporal efficacy of antimicrobials against aerobic bacteria isolated from equine endometritis: an Italian retrospective analysis (2010-2017)

This study aimed to describe bacteria isolated from the reproductive tract of mares and to identify changes in antimicrobial susceptibility patterns to those antibiotics commonly used for the treatment of equine endometritis. A total of 4122 equine uterine swabs were collected from mares suffering from reproductive tract disorders in the period 2010-2017. Aerobic culture and antimicrobial susceptibility testing using agar disc diffusion were performed on each sample. Aerobic bacteria were isolated from 3171 of 4122 (76.9 per cent) samples. The most frequently isolated microorganisms were Escherichia coli (885/3171, 27.9 per cent) and Streptococcus equi subspecies zooepidemicus (791/3171, 24.9 per cent), confirming previous findings from the literature. Antimicrobial susceptibility patterns of E coli, S equi subspecies zooepidemicus and Klebsiella pneumoniae changed over time. A statistically significant decrease in antimicrobial efficacy of cefquinome against E coli was observed over the years, as well as of ampicillin, cefquinome and penicillin against S equi subspecies zooepidemicus The high frequency of resistant bacteria isolated in the present work proceeds in the same way as indicated by surveillance data on the huge antibiotic use in Italy. As a result, testing and monitoring programmes of antimicrobial efficacy are crucial to consciously using antibiotics and preserving their effectiveness both for veterinary and human medicine.

Cytological and bacteriological sampling from filters used for embryo recovery to evaluate the uterine status of donor mares

While testing for uterine bacterial infection is usually performed prior to artificial insemination (AI), samples taken during or after embryo flushing are generally not assessed either in subfertile and old mares or in fertile mares, even though knowledge of the status of the uterine environment in which the embryo is to develop would help to predict the outcome of embryo transfer programmes. The presence of bacteria and inflammatory cells in the liquid retained in the filter after uterine flushing in donors was determined at the moment of embryo recovery. Primarily, a group of mares (n = 8) displaying evident clinical signs of endometritis was selected to evaluate the cytological and bacteriological findings in filters after uterine flushing and in uterine cotton swabs. Two uterine samples (for cytological and bacterial evaluation) were taken with cotton swabs and, subsequently, the uterus was flushed and the efflux was also subjected to bacteriological and cytological analysis. Later, a group of donors (n = 20) was also involved to evaluate the presence of bacteria and polymorphonuclear leukocytes (PMN). After embryo flushing and collection, the efflux retained in the filter was evaluated by cytology and bacteriology. A sterile cotton swab was then scrubbed on the filter mesh, and a bacterial culture was performed. The embryo recovery rate was 30% (n = 6); Escherichia coli was isolated in one efflux sample collected from embryo-productive flushings, while the other five samples were negative by culture. Bacterial growth (not considered as contamination) was observed in a total of three samples, although no inflammatory cells were detected. Bacteria were isolated in endometrial samples collected after embryo flushing in donor mares, although inflammatory cells were never present in the uterus of mares from which embryos were recovered. In the absence of clinical signs, cytological and/or bacteriological samplings are not very useful for estimating the success of embryo recovery in donor mares, but evaluation of the filter and efflux after uterine flushing in donors may provide valuable information regarding uterine status at embryo collection.

Streptococcus equi subsp. zooepidemicus Invades and Survives in Epithelial Cells

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is an opportunistic pathogen of several species including humans. S. zooepidemicus is found on mucus membranes of healthy horses, but can cause acute and chronic endometritis. Recently S. zooepidemicus was found able to reside in the endometrium for prolonged periods of time. Thus, we hypothesized that an intracellular phase may be part of the S. zooepidemicus pathogenesis and investigated if S. zooepidemicus was able to invade and survive inside epithelial cells. HEp-2 and HeLa cell lines were co-cultured with two S. zooepidemicus strains (1-4a and S31A1) both originating from the uterus of mares suffering from endometritis. Cells were fixed at different time points during the 23 h infection assay and field emission scanning electron microscopy (FESEM) was used to characterize adhesion and invasion mechanisms. The FESEM images showed three morphologically different types of invasion for both bacterial strains. The main port of entry was through large invaginations in the epithelial cell membrane. Pili-like bacterial appendages were observed when the S. zooepidemicus cells were in close proximity to the epithelial cells indicating that attachment and invasion were active processes. Adherent and intracellular S. zooepidemicus, and bacteria in association with lysosomes was determined by immunofluorescence staining techniques and fluorescence microscopy. Quantification of intracellular bacteria was determined in penicillin protection assays. Both S. zooepidemicus strains investigated were able to invade epithelial cells although at different magnitudes. The immunofluorescence data showed significantly higher adhesion and invasion rates for strain 1-4a when compared to strain S31A1. S. zooepidemicus was able to survive intracellularly, but the survival rate decreased over time in the cell culture system. Phagosome-like compartments containing S. zooepidemicus at some stages fused with lysosomes to form a phagolysosome. The results indicate that an intracellular phase may be one way S. zooepidemicus survives in the host, and could in part explain how S. zooepidemicus can cause recurrent/persistent infections. Future studies should reveal the ability of S. zooepidemicus to internalize and survive in primary equine endometrial cells and during in vivo conditions.

Endometritis: Managing Persistent Post-Breeding Endometritis

Endometritis was rated as the third most common medical problem encountered in adult horses in North America. It is the leading cause of subfertility in broodmares and is a major contributor to economic loss in the horse breeding industry, with pregnancy rates reported to be as low as 21% in mares with severe endometritis. Endometritis may be categorized as: endometrosis (chronic degenerative endometritis), acute, chronic, active, dormant, subclinical, clinical, and persistent post-breeding. These classifications are not mutually exclusive, and mares may change categories within breeding seasons or estrous cycles or may fit in multiple classifications. This chapter will focus on discussing etiology and management strategies for mares affected by persistent post-breeding endometritis. Overall, these mares are considered subfertile but acceptable pregnancy and foaling rates can be achieved with appropriate breeding management.

Endometritis: Diagnostic Tools for Infectious Endometritis

Infectious endometritis is among the leading causes of subfertility in the mare. However, the best way to reliably diagnose these cases of infectious endometritis can be confusing to the veterinary practitioner. The goal of this article is to describe how to perform various sample collection techniques, what analyses can be performed on these samples, and how to interpret the results of these analysis. Additionally, future technologies will be presented that are not currently used in equine reproduction practice.

The usefulness of uterine lavage and acute phase protein levels as a diagnostic tool for subclinical endometritis in Icelandic mares

Background

Endometritis is a common problem in a broodmare practice, often leading to infertility. The diagnosis is based on several methods such as cytology, bacteriology and histopathology; however the outcome of these methods may be inconclusive even when used together. The objectives of this study were: (1) to investigate the usefulness of acute phase proteins as an additional diagnostic tool for diagnosis of subclinical endometritis in mares and (2) to evaluate the association between macroscopic changes in uterine flushes and inflammation of the uterus. Materials were collected from 53 Icelandic mares with subclinical endometritis. Endometrial swabs and uterine lavage for cytological and bacteriological examinations and two endometrial biopsies were taken. Blood samples were collected 12–24 h after ovulation to determine the concentrations of serum amyloid A and haptoglobin in the 53 subfertile mares and, for comparison, from 20 non-pregnant mares that later conceived.

Results

Twenty-five mares were classified as positive for endometritis based on endometrial biopsy, which was used as the ‘gold standard’. We observed a correlation between cloudy efflux in the lavage and (1) polymorphonuclear cell (PMN) infiltration of the endometrium (P = 0.031), (2) positive cytology in samples obtained by cotton swabs (P = 0.019) and uterine lavage (P = 0.011), and (3) positive microbiology from samples obtained by cotton swabs (P = 0.001) and uterine lavage (P = 0.047). The degree of agreement between PMN infiltration and positive cytology from samples taken by cotton swabs and uterine lavage was fair to moderate. We found no association between the concentration of acute phase proteins and infiltration of the endometrium by PMNs, or with positive results of cytological and microbiological examinations.

Conclusions

Measurement of serum amyloid A and haptoglobin was not proven useful for diagnosis of subclinical endometritis in Icelandic mares. Macroscopic changes in the fluid collected by lavage were not consistently indicative of infection, but when present they indicate inflammation in the uterus with a high probability.

Type of Inflammation Differentially Affects Expression of Interleukin 1β and 6, Tumor Necrosis Factor-α and Toll-Like Receptors in Subclinical Endometritis in Mares

Mares that fail to conceive or lose their embryos, without showing typical signs of clinical endometritis, should be suspected of subclinical endometritis (SE). In this study, the question was addressed: does SE fully activate selected mechanisms of innate immunity in mares? For this aim, expression of mRNAs for Toll-like Receptor 2 and 4 (TLR 2/4), interleukin 1β (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor α (TNF) was examined in control mares versus either mares suffering from chronic endometritis (ChE) or subacute suppurative endometritis (SSE). The concentrations of IL-1β, IL-6 and TNF-α in supernatants from endometrial tissue cultures after 4 h incubation were measured using the enzyme immunoassay (EIA) method. Eighty-two warmblood mares, of known breeding history, were enrolled in this study. Based on histopathological assessment, mares were classified as suffering from ChE, SSE or as being healthy. In addition, immuno-localization of both TLR2 and TLR4 as well as TNF-α was investigated in the equine endometria. The mRNA expression of TLR2 (P < 0.01), IL-1β (P < 0.0001), IL-6 (P < 0.0001) and TLR4 and TNF (P < 0.05) was up-regulated in endometria of mares suffering from SSE compared with unaffected mares. Concentrations of IL-6 and TNF-α were increased only in mares exhibiting SSE, compared with unaffected (P < 0.01 for both) and ChE mares (P < 0.05 for both). Immuno-localization of TNF-α and TLRs was confirmed, both in unaffected and SE-affected endometria, and was present in the luminal and glandular epithelia and stromal cells. The severity of inflammation impacts the immune response and fosters activation of innate immunity mechanisms, as observed in the endometria of mares. The intracellular localization of TLRs and TNF-α in the endometria indicates a key role of endometrial epithelial and stromal cells in the immune response and inflammation.

The impact of low-volume uterine lavage on endometrial biopsy classification

In the mare, the low-volume uterine lavage technique allows for bacterial sampling of the entire uterine lumen and is usually performed after obtaining the traditional double-guarded endometrial swab for aerobic culture and cytology and before procurement of an endometrial biopsy sample during a breeding soundness examination. The purpose of this study was to explore the potential effects of the low-volume lavage on the endometrial biopsy classification and polymorphonuclear cell (PMNs) infiltration in the context of a breeding soundness examination. Fourteen light horse mares of mixed breed, age 7 to 21 years, with known reproductive history, were included in the study, matched by age and reproductive history, and then divided into treatment and control groups. Transrectal palpation and ultrasonography, endometrial swabbing, and the first endometrial biopsy were performed in all mares. Low-volume uterine lavage was performed in the treatment group but not the control group. After either the lavage or a 15-minute rest, a second endometrial biopsy was obtained from both the control and treatment groups. Endometrial swabs and effluent from the low-volume lavages were submitted for aerobic culture and sensitivity. Biopsy samples were fixed in Bouin's solution for 24 hours, processed, stained with hematoxylin and eosin, and then viewed under bright light microscopy. Additional staining with anti-neutrophil elastase antibody (ab68672) was performed for indirect immunohistochemistry. All samples were interpreted by a blinded observer. When the first (pre-uterine lavage) and second (post-uterine lavage) biopsies were compared using a mixed-effects logistic regression, there was no difference in endometrial biopsy classification (P = 0.74), presence of PMNs in blood vessels (P = 0.728), or infiltration of PMNs in the tissue (P = 0.934) between the treatment and control groups. In this study, the low-volume uterine lavage did not affect the endometrial biopsy classification.

KDC, Crespilho AM. SENSIBILIDADE DO LAMINOCULTIVO DERMATOBAC® PARA O DIAGNÓSTICO DA ENDOMETRITE FÚNGICA EM ÉGUAS

Resumo Dentre os diferentes fatores etiológicos, a endometrite fúngica representa uma causa frequente de infertilidade na égua. Nesse sentido, dois experimentos foram realizados para avaliar a sensibilidade do Dermatobac®, sistema originalmente desenvolvido para o isolamento de fungos de interesse em Medicina Humana. No Experimento 1, cepas padrão de Candida (n=4) e Aspergyllus (n=1) foram semeadas assepticamente e em duplicata no sistema Dermatobac®, acompanhando-se o crescimento fúngico a cada 24 horas por 7 dias. Para o Experimento 2, foram selecionadas 34 éguas, submetidas à colheita de material uterino para o plaqueamento em Dermatobac® e realização de esfregaços para pesquisa direta de fungos (Controle). No Experimento 1, foi possível a observação macroscópica de todas as cepas de Candida e Aspergyllus a partir de 24 horas do início do cultivo microbiológico. No Experimento 2, foi constatada a presença de leveduras nas lâminas citológicas de cinco animais (14,71%), resultados também confirmados na semeadura em Dermatobac® (sensibilidade de 100%). Foram observados cinco casos falso-positivos caracterizados pelo crescimento microbiológico em sistema Dermatobac® não confirmados através da citologia endometrial, resultados que determinaram a especificidade de 85%. No entanto, todos os casos falso-positivos foram atribuídos a microrganismos contaminantes que apresentaram morfologia diferenciada e tempo de crescimento superior (P<0,05) ao apresentado pelos principais agentes etiológicos das endometrites fúngicas equinas. Conclui-se que o sistema Dermatobac® é eficiente para o diagnóstico macroscópico da endometrite fúngica em equinos, gerando informações visuais a partir de 24 horas de cultivo.

Risk factors associated with uterine fluid after breeding caused by Streptococcus zooepidemicus

Infectious endometritis is a major cause of infertility in the mare and inflicts major losses on the equine breeding industry. The ability of the mare to eliminate uterine infections has been studied intensively for decades; however, despite identification of several factors contributing to the multifactorial pathogenesis and improved treatment, infectious endometritis remains a significant problem in a subpopulation of broodmares. Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is one of the most commonly isolated pathogens from the uterus of mares, suffering from infectious endometritis. Its ability to cause chronic latent infection by residing deep within the endometrial tissue has previously been described. The aim of the present study was to correlate different mare risk factors to infectious endometritis and pregnancy rates in broodmares and to investigate whether clonal or genetically distinct S. zooepidemicus strains isolated from mares with endometritis were associated with mare risk factors and the outcome of insemination. Mares (N = 152) were examined after natural cover, and 20% (31 mares) had intrauterine fluid (IUF) accumulation. Fifty-five percent (16 of 29) of the mares with IUF had infectious endometritis, and S. zooepidemicus was isolated in 81% (13 of 16) of these mares. Significantly more resting mares had IUF compared with foaling mares, and the foaling mares had the highest prevalence of positive bacterial growth from the uterine swab. The per-cycle pregnancy rate for the study was 63%. Pregnancy rate was significantly negatively affected by increased age (>12 years) and increased parity (>4), and the lowest pregnancy rate was observed in resting mares compared with foaling, barren, and maiden mares. Up to four S. zooepidemicus isolates were selected from each mare with growth of S. zooepidemicus from the uterine swab sample and further characterized by pulsed-field gel electrophoresis. In total, S. zooepidemicus isolates from 18 mares were analyzed with pulsed-field gel electrophoresis. In 13 mares, the isolates selected from each mare showed a high genetic relatedness within each individual mare, whereas two genetically distinct strains were isolated in five mares. A clonal S. zooepidemicus infection was associated with increased age, high parity, and poor vulvar conformation. Mares with clonal infection had a low pregnancy rate (38%) compared with mares with two strains isolated (80%). In conclusion, the results indicate that clonal S. zooepidemicus endometritis is associated with increased age, parity, and poor vulvar conformation in the broodmare.