Influence of Escherichia coli and Arcanobacterium pyogenes isolated from bovine puerperal uteri on phenotypic and functional properties of neutrophils

Progesterone-independent endometrial mRNA expression in dairy cows with clinical or subclinical endometritis

Up to 50 % of dairy cows fail to resolve uterine involution and develop chronic clinical (CE) or subclinical endometritis (SE) 21 days after calving. Clinical endometritis is associated with purulent discharge, while SE is not associated with overt clinical signs. Along with numerous knowledge gaps related to its pathogenesis, SE does not allow for a straightforward and effective therapy. Therefore, it is crucial to unravel differences in the expression of genes among healthy, CE, and SE cows. This might contribute to the discovery of new drug candidates and, in consequence, a potentially effective treatment. In the present study, cows between 21 and 28 days postpartum (PP) were examined using vaginoscopy for the presence of vaginal discharge and endometrial cytology for the determination of the endometrial polymorphonuclear cell (PMN) percentage. Next, an endometrial biopsy sample was taken to investigate the expression of 13 selected candidate genes by qPCR. Uterine health status was assigned to healthy (absence of abnormal vaginal discharge and ≤5 % PMN, n = 13), SE (absence of abnormal vaginal discharge and >5 % PMN, n = 30), and CE (mucopurulent or purulent vaginal discharge and >5 % PMN, n = 9). At the same time, a blood sample was collected to assess serum progesterone concentration and to categorize cows as low (≤1 ng/mL) or high (>1 ng/mL) in progesterone. High expression of IL1B, IL6, IL17A, CXCL8, PTGES, PTGS1, PTGS2, and INHBA genes and low expression of FST was noted in the endometrium of CE compared to healthy cows. Increased endometrial INHBA expression was observed in both SE and CE compared to healthy cows. Interestingly, greater expression of PTGES and PRXL2B genes and lower expression of PTGS2 were characteristic of SE versus CE or healthy. Among cows with no overt clinical symptoms of uterine disease (healthy and SE), the endometrial expression of IL1 B, CXCL8, and PTGES was greater in cows with high versus low serum progesterone. Several genes were differentially expressed among healthy, SE, and CE cows indicating different pathways for the development of different uterine diseases. In conclusion, we found progesterone-independent SE markers, which suggests that low endometrial PTGS2 expression may be indicative of an inadequate immune response and thus contribute to the pathogenesis of SE.

Association of intrauterine presence of Lactobacillus spp. with inflammation and pathogenic bacteria in the uterus in postpartum dairy cows

The aim of this study was to clarify the influence of Lactobacillus spp. on the degree of endometrial inflammation in the postpartum period and the relationship between Lactobacillus spp. and pathogenic bacteria in the endometrium of postpartum dairy cows. Endometrial samples were collected from 41 Holstein-Friesian cows at 4 and 8 weeks postpartum using cytobrushes for polymorphonuclear neutrophil (PMN) count and bacterial culture to isolate Lactobacillus spp., Escherichiacoli, and Trueperella pyogenes. The 4-week samples were divided into four groups (E+L+), (E+L−), (E−L+), (E−L−) according to whether endometritis was diagnosed (E+) and Lactobacillus spp. was isolated (L+). The diagnostic criterion for cytological endometritis was > 18% PMN. The average PMN% in the E+L+ group was lower than that in the E+L-group (P < 0.05) at 8 weeks postpartum. There were no significant correlations between the number of colonies of Lactobacillus spp. and E. coli or between that of Lactobacillus spp. and T. pyogenes. Lactobacillus spp. could reduce PMN% in dairy cows with endometritis during the puerperal period. In conclusion, the intrauterine presence of Lactobacillus spp. may have a positive effect on uterine involution in postpartum dairy cows.

Peripartum changes in the activity and expression of neutrophils may predispose to the postpartum occurrence of metritis in dairy cows

Metritis is a postpartum uterine pathology that causes a huge economic loss due to increased culling risk and impaired milk yield and reproduction in cows. The present study was carried out to study the changes in the activity and expression of blood neutrophils in crossbred dairy cows with and without metritis. Collection of blood samples was done at -3, -2 and - 1 weeks before calving, at calving and during the first day of metritis diagnosis in metritis group (n = 8) or at day 8-10 post calving in healthy group (n = 8). Neutrophils were studied for its percentage (microscopically), respiratory burst (nitro blue tetrazolium assay), myeloperoxidase (MPO) concentrations (sandwich ELISA) and expression of CXCR1, CXCR2, TLR2, TLR4, GRα, CD11b, CD14, CD25, CD44, CD47 and CD62L (RT-PCR). Immunocytochemistry was used to investigate MPO concentration and CD14 activity, and western blotting was used for estimating MPO. Although most of these parameters changed in the cows that developed metritis one week before calving, MPO and CD14 got altered much earlier. Myeloperoxidase concentrations and expression of CD14 were considerably lower starting from -2 weeks before calving in cows that developed metritis compared to healthy cows. Further studies are warranted to study the possible use of MPO and CD14 to identify transition cows more vulnerable to develop metritis several weeks before disease occurrence.

Potential roles of neutrophils in maintaining the health and productivity of dairy cows during various physiological and physiopathological conditions: a review

Neutrophils represent the first line of innate immunity and are the most prominent line of cellular defence against invading microorganisms. On stimulation, they can quickly move through the walls of veins and into the tissues of the body to immediately attack or monitor the foreign antigens. Neutrophils are highly versatile and sophisticated cells which are endowed with highly sensitive receptor-based perception systems. They were traditionally classified as short-lived phagocytes actively involved during infection and inflammation, but recently, it has been seen that neutrophils are capable of detecting the presence of sperms during insemination as well as an implanting embryo in the female reproductive tract. These specialised phagocytes play a major role in tissue remodelling and wound healing, and maintain homeostasis during parturition, expulsion of placenta, folliculogenesis, corpus luteum formation and luteolysis. Here, we review the role played by neutrophils in maintaining homeostasis during normal and inflammatory conditions of dairy cattle. We have summarised the alteration in the expression of some cell adhesion molecules and cytokines on bovine neutrophils during different physiological and physiopathological conditions. Some emerging issues in the field of neutrophil biology and the possible strategies to strengthen their activity during the period of immunosuppression have also been discussed.

Dose related effects of LPS on endometrial epithelial cell populations from dioestrus cows

Lipopolysaccharides (LPS) from Gram negative bacteria are involved in the pathogeny of uterine diseases in cows. This study aimed to investigate LPS effects on the growth of bovine endometrial epithelial cells (bEEC) and relationships between LPS response and tissue characteristics. Uteri from 35 females were characterized for parity and stage of oestrous cycle. Densities of glandular tissue (dGT), CD11b+ cells and Ki67+ cells were measured in the endometrial tissue. Cells from 13 dioestrus cows were exposed to 0, 2, 4, 8, 12, 16 or 24μg/mL LPS. Effects of parity and stage of the oestrous cycle on tissue characteristics and effects of LPS dosage, cow and tissue characteristics on changes in cell numbers were analyzed by ANOVA. The dGT was higher in metoestrus and dioestrus samples than in pro-oestrus ones whereas densities of CD11b+ and Ki67+ cells were higher at pro-oestrus (p<0.05-p<0.01). LPS influenced bEEC populations in a dose related manner. An increase in number of live cells was observed for dosages ranging from 2 to 12μg/mL LPS (p<0.0001 vs controls). No effect was found on numbers and frequencies of dead cells. With higher dosages, the numbers of live cells did not increase but the numbers of dead did increase. No relationships were observed between cow or tissue characteristics and growth patterns or frequencies of viable bEEC in controls nor in the response to LPS. To conclude this model is suitable for further studies on dysregulations induced by LPS in endometrial tissue.

Potential of acute phase proteins as predictor of postpartum uterine infections during transition period and its regulatory mechanism in dairy cattle

Among the various systemic reactions against infection or injury, the acute phase response is the cascade of reaction and mostly coordinated by cytokines-mediated acute phase proteins (APPs) production. Since APPs are sensitive innate immune molecules, they are useful for early detection of inflammation in bovines and believed to be better discriminators than routine hematological parameters. Therefore, the possibility of using APPs as a diagnostic and prognostic marker of inflammation in major bovine health disorders including postpartum uterine infection has been explored by many workers. In this review, we discussed specifically importance of postpartum uterine infection, the role of energy balance in uterine infections and potential of APPs as a predictor of postpartum uterine infections during the transition period and its regulatory mechanism in dairy cattle.

Detection of genes encoding multidrug resistance and biofilm virulence factor in uterine pathogenic bacteria in postpartum dairy cows

Reckless use of antibiotics and/or development of biofilm are the rationale for the development of multidrug resistance (MDR) of pathogenic bacteria. The objective of the present study was to detect MDR genes in Trueperella pyogenes and to detect biofilm virulence factor (VF) genes in Escherichia coli isolated from the uterus of postpartum dairy cows. Uterine secretions from different parity postpartum Holstein cows (n = 40) were collected using cytobrush technique after a sterile procedure from cows with varying degree of uterine inflammatory conditions. The cytobrush was stored in a specimen collector, placed in a cooler with ice, and transported to the laboratory within 2 hours. The pathogens were isolated and were identified initially by their colony morphology and biochemical characteristics. To further identify and classify the single species, and to determine the presence of MDR and VF genes, the genes fragments were amplified using the respective primers by either singleplex or multiplex polymerase chain reaction protocol, and amplicons were detected by electrophoresis method. T pyogenes was isolated in 17 of 40 (42.5%) cows in the study population as recognized by the 16S rRNA gene. Of the positive T pyogenes samples, 8 of 17 (42.1%) were positive for integron type 1 (intI I), and none were positive for integron type 2 (intI II). Of those 8 positive for intI I, six of eight (66.7%) were positive for amplicons aadA5 and aadA24-ORF1 at 1048 and 1608 bp, respectively, associated with specific drug resistance. Presence of addA5 indicated resistance to sulfadiazine, bacitracin, florfenicol, and ceftiofur. Presence of addA24-ORF1 indicated resistant to sulfadiazine, bacitracin, penicillin, clindamycin, and erythromycin. E coli was isolated in 18 of 40 (45.0%) cows in the study population. The genes for VF, Agn43a, and Agn43 b, associated with biofilm production, were found in 6 of 18 (33.3%) of the positive isolates. Both T pyogenes MDR gene and E coli biofilm VF existed in more severe form of uterine diseases than subclinical endometritis. In conclusion, 35% of T pyogenes isolates found were positive for a gene cassette associated with antibiotic resistance, and 33% of the E coli isolates contained genes for the VF associated with biofilm production.

Persistence of uterine bacterial infection, and its associations with endometritis and ovarian function in postpartum dairy cows

We investigated the relationship between the persistence of uterine bacterial infections with cytologically determined endometritis and ovarian function in 65 postpartum Holstein cows. Vaginal mucus discharges were collected, and endometrial smear samples (n = 130) were collected for cytological and bacteriological examinations from the cows at weeks 5 and 7 postpartum (pp). Blood samples were collected at weeks 3, 5 and 7 pp to determine plasma progesterone concentrations to monitor ovarian activity. According to the bacteriological examination, cows were classified into four groups. The first group (n = 32; 49%) comprised cows negative for bacteria at weeks 5 and 7 pp. The second group (n = 11; 17%) comprised cows with bacterial infections at week 5 pp but that were clear of infection at week 7 pp. The third group (n = 12; 19%) comprised cows without bacteria at week 5 pp but that acquired an infection by week 7 pp. The fourth group (n = 10; 15%) comprised cows with bacterial infections at weeks 5 and 7 pp (persistence of infection). A positive correlation (P < 0.001) was noted between the severity of cytologically determined endometritis, purulent vaginal discharge and the persistence of infection. Cows with persistent infections had a significantly (P < 0.01) prolonged luteal phase compared with cows without infection. In conclusion, the prevalence of cytologically determined endometritis and prolonged luteal phase were significantly increased in cows with persistent infections.

Trueperella pyogenes and Escherichia coli as an etiological factor of endometritis in cows and the susceptibility of these bacteria to selected antibiotics

The aim of this study was to determine the percentage of participation of particular species of microorganisms, isolated from the uterus of cows with endometritis and from cows without inflammatory lesions of the uterus, in the same postpartum period. The aim of the study was also to examine how long after parturition non-treated endometritis persists. Moreover, antibiotic susceptibility tests were carried out of the bacterial isolates dominating in the uterus. Forty cows were included in the study: 20 cows with endometritis (experimental group) and 20 cows without any inflammatory condition of the uterus (control group). The material for cytological and bacteriological tests was collected on the 5th, 26th, 40thand 60thday after parturition, using an intrauterine brush adapted for cows. The total number of collected isolates was 149, including 120 isolates from the uterus of cows with endometritis and 29 isolates from the uterus of cows without endometritis. The following species of microorganisms were isolated from the material collected from cows with endometritis: T. pyogenes (49.2%), E.coli (22.5%), F. necrophorum (11.7%), Staphylococcus sp. (6.7%), B. melaninogenicus (5.8%), and Streptococcus sp. (4.1%). The participation percentage of particular species of bacteria in the material collected from the uterus of cows without endometritis was as follows: T. pyogenes (27.6%), E.coli (24.2%), Staphylococcus sp. (20.7%), Streptococcus sp. (20.7%), B. melaninogenicus (3.4%) and F. necrophorum (3.4%). The highest percentage of T. pyogenes isolates was susceptible to ceftiofur (89.6%); cefoperazone (85.1%) and amoxicillin combined with clavulanic acid (79.1%). E. coli isolates were most susceptible to amoxicillin combined with clavulanic acid (100%), cefoperazone (94.1%) and oxytetracycline (82.3%).

The effect of prepartum intravaginal bacteriophage administration on the incidence of retained placenta and metritis

The objective of this study was to evaluate the effect of prepartum intravaginal administration of an anti-Escherichia coli bacteriophage cocktail on uterine health and reproductive performance of lactating dairy cows. The study was conducted on a commercial dairy farm located near Ithaca, New York, from March to September 2012, and 107 cows were enrolled. The cows were divided randomly into 2 groups (treatment and control); treatment group cows were submitted to 3 intravaginal administrations of 20 mL of a bacteriophage cocktail including 10 different phages in a lysate with titration of approximately 10(9) plaque-forming units, on d 230, 260, and 275 of gestation. Control cows were not treated with a placebo, and physical examination and sample collection was conducted equally for both groups. Vaginal swabs were collected at d 230, 260, and 275 d of gestation, cervical swabs were collected at 3±1 d in milk, and blood was collected at 275 d of gestation for nonesterified fatty acids and interleukin (IL)-6 serum level measurements and at 10 DIM for β-hydroxybutyrate and IL-6 serum level measurements. The bacteriophage cocktail significantly increased the incidence of retained placenta and metritis. Swab samples were cultured for E. coli and no difference was found between treatment and control groups. The lysate contained 6×10(9) IU of lipopolysaccharide/mL and could have caused prepartum overstimulation of toll-like receptor-4 (TLR4)-chemokine pathway, leading to a weaker immune response. However, IL-6 was not affected by treatment, although sample size was insufficient to prove a treatment effect on the suppression of the chemokine cascade and innate immune system. Bacteriophage treatment had an excellent bactericidal effect in previous in vitro trials; however, special attention must be given to production of the cocktail to obtain a purified solution free of E. coli bacterial products and fragments, particularly lipopolysaccharide.

Presence of Escherichia coli, Trueperella pyogenes, α-hemolytic streptococci, and coagulase-negative staphylococci and prevalence of subclinical endometritis

Subclinical endometritis (SCE) has a severe negative effect on reproductive performance of dairy cows. Different studies have shown a wide variety of cut points for the polymorphonuclear neutrophilic leukocyte (PMNL) percentage to define SCE and differing sampling times. Possible risk factors for SCE, such as low body condition score, hyperketonemia, and increased haptoglobin concentrations have been demonstrated. The aim of this study was to determine the relationship between bacterial findings in the uterus and PMNL in the early postpartum period and to compare 2 classification schemes for the diagnosis of SCE. Cytological and bacteriological samples from the uterus were taken from 149 cows at 2 consecutive times postpartum [10 ± 1 and 24 ± 1 d in milk (DIM)] and additionally, 131 cows were sampled at 21 to 27 DIM. For sample collection, the cytobrush technique was used and vaginal discharge was examined by vaginoscopy. Polymorphonuclear neutrophilic leukocyte cut points were set at 5, 10, and 18%. Cows positive with α-hemolytic streptococci at 10 ± 1 DIM had significant higher PMNL percentages at 21 to 27 DIM and greater median days to pregnancy (193.5d) than cows not infected (123.0 d). Cows with Trueperella pyogenes at 10±1 DIM had higher odds (5.2) of having more than 18% PMNL at 21 to 27 DIM compared with cows without infection. Escherichia coli had no effect on the prevalence of SCE regardless of the cut point. Primiparous cows with more than 18% PMNL had greater median days to pregnancy (144.5 d) than cows with less than 5% (80.0 d) or cows between 5 and 18% PMNL (68.0 d). Cows between 5 and 18% PMNL or 10 and 18% PMNL showed the best reproductive performance. The results demonstrate that an early infection with α-hemolytic streptococci increased the PMNL percentage 2 wk later and that 18% PMNL at 21 to 27 DIM was a predictive cut point for primiparous cows to diagnose animals with or without SCE.

Diversity and succession of bacterial communities in the uterine fluid of postpartum metritic, endometritic and healthy dairy cows

The diversity of the uterine bacterial composition in dairy cows is still poorly understood, although the emerging picture has shown to be increasingly complex. Understanding the complexity and ecology of microorganisms in the uterus of postpartum dairy cows is critical for developing strategies to block their action in reproductive disorders, such as metritis/endometritis. Here, we used PCR-Denaturing Gradient Gel Electrophoresis (DGGE) and DNA pyrosequencing to provide a comprehensive description of the uterine bacterial diversity and compare its succession in healthy, metritic and endometritic Holstein dairy cows at three intervals following calving. Samples were collected from 16 dairy cows housed in a dairy farm located in upstate New York. PCR-DGGE revealed a complex profile with extensive differences in the community structure. With few exceptions, clustering analysis grouped samples from cows presenting the same health status. Analysis of >65,000 high-quality 16S rRNA gene sequences showed that the uterine bacterial consortia, regardless of the health status, is mainly composed of members of the phyla Bacteroidetes, Fusobacteria, Firmicutes, Proteobacteria, and Tenericutes. In addition to these co-dominant phyla, sequences from Spirochaetes, Synergistetes, and Actinobacteria appear less frequently. It is possible that some sequences detected in the uterine fluid resulted from the presence of fecal or vaginal contaminants. Overall, the bacterial core community was different in uterine fluid of healthy cows, when compared to cows suffering from postpartum diseases, and the phylogenetic diversity in all the combined samples changed gradually over time. Particularly at the 34–36 days postpartum (DPP), the core community seemed to be specific for each health status. Our finding reveals that the uterine microbiota in dairy cows varies according with health status and DPP. Also, it adds further support to the hypothesis that there is uterine contamination with diverse bacterial groups following calving and emphasizes the role of unidentified microorganisms in this context.

Relationship between bacteriological findings in the second and fourth weeks postpartum and uterine infection in dairy cows considering bacteriological results

The uterine lumen in early postpartum dairy cows is contaminated with different bacteria. The most relevant uterine pathogens are Escherichia coli and Trueperella pyogenes. Prevalence of α-hemolytic streptococci and coagulase-negative staphylococci (CNS) is also high; however, these pathogens are considered opportunistic. The overall objective of this study was to investigate effects of the intrauterine presence of E. coli, T. pyogenes, α-hemolytic streptococci, or CNS at 10±1 d in milk (DIM) on the type of bacteria 2 wk later and their influence on uterine infections and subsequent reproductive performance. Furthermore, we set out to quantify 2 relevant methodological factors (i.e., laboratory and sampling instrument). Bacteriological samples were collected at 10±1 and 24±1 DIM from the uterine lumen using a cytobrush (CB). Vaginal mucus was classified by vaginoscopy. In a subsample, bacteriological results of 3 different laboratories and of CB and cotton swabs (CS) were compared. Samples of uterine discharge were collected at 10±1 DIM and bacteriological samples were taken using CB and CS. Bacteria were identified and bacterial growth quantified on a 4-point scale. Animals infected with E. coli or T. pyogenes at 10±1 DIM had a higher risk for an infection with the same bacterial species at 24±1 DIM [E. coli relative risk (RR)=3.7 and T. pyogenes RR=2.9]. Moreover, the risk of being diagnosed with abnormal vaginal discharge at 24±1 DIM increased in cows with E. coli (RR=1.7) or T. pyogenes (RR=1.7) at 10±1 DIM. Uterine infection with α-hemolytic streptococci or CNS did not increase the risk of an infection with T. pyogenes or E. coli or abnormal vaginal discharge 2 wk later. Cows with E. coli at 10±1 DIM or T. pyogenes at 24±1 DIM had greater days to first artificial insemination than cows positive for the 3 remaining bacterial species. Cows with T. pyogenes at 10±1 DIM had more days to pregnancy and more cows were culled when positive for E. coli at 10±1 DIM. Agreement of bacteriological results of 3 different laboratories were significant for laboratory A + B and A + C for the CB and CS. The highest agreement considering the bacterial species was for E. coli. All results for laboratory A + B and A + C for the CB and CS were significant. The results generated from samples collected with CB agreed nicely with those from CS from each laboratory (laboratory A: 250/272; laboratory B: 264/272; laboratory C: 253/272).

Susceptibility of Escherichia coli isolated from uteri of postpartum dairy cows to antibiotic and environmental bacteriophages. Part I: Isolation and lytic activity estimation of bacteriophages

The objective of this study was to isolate bacteriophages from environmental samples of 2 large commercial dairy farms using Escherichia coli isolated from the uteri of postpartum Holstein dairy cows as hosts. A total of 11 bacteriophage preparations were isolated from manure systems of commercial dairy farms and characterized for in vitro antimicrobial activity. In addition, a total of 57 E. coli uterine isolates from 5 dairy cows were phylogenetically grouped by triplex PCR. Each E. coli bacterial host from the uterus was inoculated with their respective bacteriophage preparation at several different multiplicities of infections (MOI) to determine minimum inhibitory MOI. The effect of a single dose (MOI=10(2)) of bacteriophage on the growth curve of all 57 E. coli isolates was assessed using a microplate technique. Furthermore, genetic diversity within and between the different bacteriophage preparations was assessed by bacteriophage purification followed by DNA extraction, restriction, and agarose gel electrophoresis. Phylogenetic grouping based on triplex PCR showed that all isolates of E. coli belonged to phylogroup B1. Bacterial growth was completely inhibited at considerably low MOI, and the effect of a single dose (MOI=10(2)) of bacteriophage preparations on the growth curve of all 57 E. coli isolates showed that all bacteriophage preparations significantly decreased the growth rate of the isolates. Bacteriophage preparation 1230-10 had the greatest antimicrobial activity and completely inhibited the growth of 71.7% (n=57) of the isolates. The combined action of bacteriophage preparations 1230-10, 6375-10, 2540-4, and 6547-2, each at MOI=10(2), had the broadest spectrum of action and completely inhibited the growth (final optical density at 600 nm <or=0.1) of 80% of the E. coli isolates and considerably inhibited the growth (final optical density at 600 nm <or=0.2) of 90% of the E. coli isolates. Restriction profile analysis demonstrated that all 4 phage preparations contained bacteriophages that were genetically distinct from each other according to the banding pattern of the fragments. The combination of several different bacteriophages can improve the spectrum of action, and the results of this study suggest that bacteriophages 1230-10, 6375-10, 2540-4, and 6547-2 should be used in combination as a cocktail.

Postpartum uterine infection in cattle

Postpartum uterine infections results from uterine contamination with bacteria during parturition. The prevalence of uterine infections varies considerably among studies. Uterine infection implies adherence of pathogenic organisms to the mucosa, colonization or penetration of the epithelium, and/or release of bacterial toxins that lead to establishment of uterine disease. The development of uterine disease depends on the immune response of the cow, as well as the species and number (load or challenge) of bacteria. The postpartum uterus has a disrupted surface epithelium in contact with fluid and tissue debris that can support bacterial growth. A variety of species of bacteria, both Gram-positive and Gram-negative aerobes and anaerobes, can be isolated from the early postpartum uterus. Most of these are environmental contaminants that are gradually eliminated during the first 6 weeks postpartum. A normal postpartum cow resolves uterine infection by rapid involution of the uterus and cervix, discharge of uterine content, and mobilization of natural host defenses, including mucus, antibodies and phagocytic cells. Clinical signs of uterine infection vary with the virulence of the causative organisms and the presence of factors that predispose to the disease. The treatment of endometritis and metritis in bovine should be directed towards improving fertility. The antibiotic should be active against the main uterine pathogens and should maintain its activity in the environment of the uterus. Also, should not inhibit the normal defense mechanisms and should be well tolerated and not induce irritation in the endometrium. Effective use of hormones in uterine infection requires knowledge of both normal reproductive endocrinology and the therapeutic characteristics of available hormonal preparations.

Bacterial isolates associated with dystocia and retained placenta in iraqi buffaloes

The present study was conducted on 50 recently calved Iraqi Buffalo cows. Depending on the kind of parturition, buffalo cows were divided into two main groups, the first group had normal unassisted parturition (NP) (26 animals) and the second group with certain periparturent complications (PPC) (24 animals). After 24 h of parturition, these two groups were further subdivided into two groups as cows expel their foetal membranes in <24 h postpartum and referred as non-retained placenta (NRP) while cows that did not expel their foetal membrane after 24 h referred as retained placenta (RP). Sampling for bacteriology, uterine discharge for polymorphonuclear cells per cent and blood samples for polymorphonuclear neutrophil (PMN) and the enzyme creatine kinase activity were performed at 6, 24 and 48 h postpartum. In PPC group, the most prevalent bacteria after 6 h of calving were Escherichia coli, beta-haemolytic Streptococci and Lactobacillus acidophilus. Total bacterial isolates in the uterus of buffaloes with RP in PPC group after 24 and 48 h were 129 and 183 respectively. Among the isolates, Archanobacterium pyogenes, Fusobacterium necrophorum, Prevotella melaninogenicus and Staphylococcus aureus were the most prevalent isolates after 48 h of RP buffaloes in PPC group. Polymorphonuclear neutrophil were significantly (p < 0.01) increased in the uterine discharge than in blood in buffaloes with RP in both PPC and NP groups. In conclusion, uterine contamination occurs as a result of postpartum ascending contamination by non-specific environmental organisms. The presence of Lactobacillus sp. in the uterus indicated a healthy uterus. Peripartum complications followed by retention of foetal membranes with the dominance of E. coli in the uterine lumen might favour the colonization of other bacteria including facultative anaerobic and strictly anaerobic in the uterine wall of buffaloes.

The relationship between uterine pathogen growth density and ovarian function in the postpartum dairy cow

In cattle, the first postpartum dominant follicle grows slower and produces less oestradiol in animals with high numbers of bacteria contaminating the uterine lumen. However, only bacteria that are uterine pathogens are correlated with severe clinical disease and an increased inflammatory response. It is unknown whether the effect on the ovary in relation to uterine bacterial contamination is associated with the presence of recognised uterine pathogens. Therefore, the present study examined the relationship between pathogenic bacteria in the postpartum uterine lumen, follicle growth and function and the formation of a competent corpus luteum. In addition, peripheral plasma concentrations of immune mediators were quantified. Swabs were collected from the uterine lumen of cattle on day 7 postpartum. Bacteria were cultured and identified and bacterial growth was scored semi-quantitatively. Animals were categorized into high or low recognized uterine pathogen contamination groups based on the number of colonies. Ovarian structures were monitored by daily transrectal ultrasonography and blood samples were collected. In animals with high numbers of uterine pathogens on day 7 postpartum, the diameter of the first postpartum dominant follicle was smaller and plasma oestradiol concentrations were lower. In addition, these animals had smaller corpora lutea, which produced less progesterone. Furthermore, animals with a high day 7 uterine pathogen growth density had higher peripheral concentrations of acute phase proteins. Thus, contamination of the uterus with recognized uterine pathogens is associated with ovarian dysfunction during the postpartum period. Furthermore, infection results in an increase in the production of inflammatory mediators.

Probiotic properties of vaginal lactic acid bacteria to prevent metritis in cattle

AIMS

The isolation of bovine vaginal lactic acid bacteria (LAB) and the screening of their beneficial properties to select those that could be used as probiotics in the prevention of bovine metritis were performed.

METHODS AND RESULTS

Out of 76 Lactobacillus sp. and seven Streptococcus sp. strains, a small number showed high- and medium hydrophobicity when the microbial adhesion to hydrocarbons method (MATH) was applied. In the agar plate diffusion test, a large number of strains inhibited vaginal bovine Escherichia coli 99/14 and human E. coli. This inhibition was due to acid. Only a few strains inhibited Actinomyces pyogenes 96/393, a pathogen isolated from bovine metritis. This inhibition remained after neutralization. The taxonomic identification of the selected strains was carried out by an amplified ribosomal DNA restriction analysis (ARDRA). Most of the strains were identified as Lactobacillus fermentum, a few as Lactobacillus gasseri and one as Lactobacillus rhamnosus.

CONCLUSIONS

Bovine vaginal lactobacilli strains have differential surface properties. The strains selected are capable of inhibiting specific metritis pathogens.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results can be applied for future studies to design a probiotic product to prevent metritis in dairy postpartum cows.

Serum protein pattern during cow pregnancy: Acute-phase proteins increase in the peripartum period

Serum collected in a time-course mode during the pregnancy of a group of heifers was analyzed by 2-DE under various experimental conditions to optimize resolution of all protein spots. Changes in the levels of some components were detected during the last phase of pregnancy and early postpartum. These included a decrease of alpha2-HS-glycoprotein, an increase of alpha1-antichymotrypsin and, with a much larger and more abrupt variation, of orosomucoid and haptoglobin. These findings associate the weeks preceding calving with an acute-phase reaction. Analysis of individual animal's sera by 1-DE demonstrated a higher level of orosomucoid in the sera of cows developing postpartum endometritis during the 2 wk after calving (i.e., in the course of the infection) but a lower level during the 2 wk before calving. This observation could represent an important tool for the prepartum detection of animals prone to develop postpartum endometritis and lead to a more accurate peripartum management of those animals.

Immune responses during the peripartum period in dairy cows with postpartum endometritis

Determining the immune responses to the development of endometritis during the peripartum period may assist in the development of more efficient reproductive management regimens for dairy herds. In this study, we compared the peripartum immune responses of dairy cows that develop endometritis by 4 weeks postpartum (n = 11) to cows that did not develop this disease (n = 19). Blood samples were collected 1 week before calving, just after or during calving, and then at weeks 1, 2, 3, and 4 postpartum. Cows that developed endometriris had significantly higher total leukocyte, neutrophil, lymphocyte, and monocyte counts than the control cows (P < 0.05) at all time points. The leukocytes from cows that developed endometritis were significantly less phagocytic than those from control cows at all sampling time points (P < 0.01). The serum TNFalpha concentrations of the control cows decreased linearly from the prepartum time point (P = 0.0029), but the endometritis cows showed a different profile (P > 0.05). As a result, the serum TNFalpha concentrations were greater in the endometritis group (P < 0.01) than in the control group during the third and fourth weeks postpartum. The greater total leukocyte numbers and neutrophil, lymphocyte and monocyte counts, and the maintenance of elevated serum TNFalpha levels in the cows with endometritis may be due to infection in the postpartum period. Furthermore, the decreased phagocytic capacity of leukocytes during the peripartum period, including at the prepartum time point, makes cows more susceptible to postpartum endometritis.

Effects of Induced Clinical Mastitis During Preovulation on Endocrine and Follicular Function

The objective of the study was to determine if experimentally induced clinical mastitis before ovulation resulted in alterations of endocrine function, follicular growth, or ovulation. On d 8 (estrus = d 0), cows were challenged (TRT; n = 19) with Streptococcus uberis or were not challenged (control; n = 14). Forty-eight hours after induction of luteal regression on d 12, blood samples were collected to determine estradiol-17beta, LH pulse frequency, and occurrence of the LH surge. Ovaries were scanned to monitor follicular growth and ovulation. Cows with clinical mastitis (n = 12) had elevated rectal temperatures, somatic cell counts, and mammary scores. Estrus and ovulation occurred in 4 of 12 clinically infected cows and in all control cows. Cows that were challenged but did not develop clinical mastitis (n = 5) displayed estrus and ovulated. Due to differences in expression of estrus, cows were further subdivided for analyses into 4 groups: control, TRT-EST (infected cows that displayed estrus; n = 4), TRT-NOEST (infected cows that did not display estrus; n = 8), and NOMAS (cows that were inoculated but did not develop mastitis; n = 4). Ovulation rate was 100% for CON, NOMAS, and TRT-EST compared with 0% for TRT-NOEST cows. Size of the ovulatory follicle ("presumed" ovulatory follicle in TRT-NOEST cows) was similar for all groups. Frequency of LH pulses was decreased in TRT-NOEST compared with CON, TRT-EST, and NO-MAS. Estradiol-17beta increased over time in CON, NO-MAS, and TRT-EST cows, but did not increase in TRT-NOEST cows. Cows with clinical mastitis may exhibit estrus and ovulate normally or have disruptions in normal physiology including decreased LH pulsatility, absence of an LH surge and estrous behavior, suppressed estradiol-17beta, and failure to ovulate.

The postpartum uterus

The cow is notable among the domestic species for the almost ubiquitous bacterial contamination of the uterine lumen after parturition and the high incidence of clinical uterine disease. Such uterine disease not only disrupts uterine tissues, but also ovarian follicle growth and function by perturbation of the hypothalamus, pituitary, and ovary. Other events such as the postpartum negative energy balance also have similar multilevel effects on postpartum endocrinology. Return of ovarian cyclical activity is dependent on the innate immune system resolving uterine bacterial contamination,prompt uterine involution, and a short interval to the negative energy balance nadir. Although the risk factors for uterine disease have been described, preventive strategies are not widely adopted. Thus, veterinarians must identify and treat uterine disease efficiently to limit their negative effect on fertility.

Peripartal Propylene Glycol Supplementation and Metabolism, Animal Health, Fertility, and Production in Dairy Cows

The effect of peripartal supplementation with concentrate enriched at 10% propylene glycol (PG) on metabolism, animal health, fertility, and milk production was studied using 234 cows from 8 dairy farms with production averages of 8019 to 10,656 kg/yr. The feeding schedule for the PG group (n=117) was as follows: 13 d antepartum: 1.5 kg/d (= 150 mL PG); 12 d antepartum until parturition: 3 kg/d (= 300 mL PG); 1 to 12 d postpartum: 1 kg/d (= 100 mL PG). Control cows (n=117) received the same concentrate without PG. From a subset of cows (PG: n = 43; control: n = 40), blood samples were collected at 6, 3, and 1 wk antepartum, 3 d antepartum, on the day of parturition, and 1, 3, 5, 7, 9, and 11 wk postpartum for the determination of nonesterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), insulin-like growth factor (IGF)-I, and activities of aspartate-aminotransferase (AST) and glutamate-dehydrogenase (GLDH). From another subset of cows (PG: n=11; control: n=10), blood samples were collected 1 wk antepartum, on the day of parturition, and 1 wk postpartum to determine immunophenotypical and functional parameters of blood neutrophils. From 1 wk antepartum to 1 d postpartum, concentrations of NEFA were significantly lower in cows receiving PG compared with controls. Also, concentrations of BHBA in cows receiving PG were significantly lower from 1 wk antepartum until 7 wk postpartum. Concentrations of IGF-I were significantly higher in the PG group, from 1 wk antepartum until 1 wk postpartum than in the control group. Activities of AST and GLDH did not differ between groups. Immunophenotypical and functional characteristics of blood neutrophils were not influenced by treatment nor were animal health, reproduction, or milk production. Although indicators of metabolic status were improved by peripartal use of PG-enriched concentrate, economic benefits are questionable for dairy farms with good nutritional programs, as economically important factors such as milk production, animal health, and fertility were not influenced.

Degenerative Endometrial Changes do not Change the Functional Capacity of Immigrating Uterine Neutrophils in Mares

An endometritis model was used to investigate the influence of degenerative endometrial changes (endometrosis) on functional parameters of uterine neutrophils in the horse. Six hours after intrauterine application of recombinant human interleukin-8 (rhIL-8), the uteri of 15 mares were flushed with phosphate-buffered saline. Quantitative and qualitative flow cytometric assays were then made to determine the absolute numbers, viability, phenotype, generation of reactive oxygen species (ROS), and phagocytic activity of immigrated polymorphonuclear neutrophilic granulocytes (PMN). Recombinant hIL-8 attracted similarly high numbers of similarly viable PMN into the uteri of mares with or without degenerative endometrial changes. Compared with blood PMN, immigrated uterine neutrophils displayed significantly upregulated expression of CD11a/CD18 (LFA-1) on uterine PMN whereas major histocompatibility complex class I molecules were expressed at lower densities. The ability to phagocytose opsonized streptococci did not differ between uterine and blood PMN. However, uterine PMN displayed a higher capacity to generate ROS. On average, uterine PMN of mares with degenerative endometrial changes showed phenotypical and functional characteristics similar to those of mares with a histologically healthy endometrium. Therefore, degenerative endometrial changes per se did not reduce the functional capacity of equine uterine neutrophils in mares.

Development and comparison of in vivo and in vitro models for endometritis in cows and mares

In order to investigate pathogenic mechanisms of acute endometritis in cows and mares, we established an in vivo model in both species. Based on the results of an in vitro transmigration system, human recombinant interleukin-8 (rhIL-8; 1.25 microg per mare and 5 microg per cow in 50 ml phosphate-buffered saline) was used to attract polymorphonuclear neutrophil granulocytes (PMNs) into the uteri. Peak numbers of uterine neutrophils were attracted after 6h, in both cows and mares. On average, mares responded more sensitively than cows, with 15 times higher numbers of rhIL-8-attracted uterine neutrophils (72+/-8 x 10(7)cells). In contrast to in vitro studies, in vivo migrated neutrophils (uterine neutrophils) of both species displayed a significantly reduced MHC class I expression. Expression of the CD11a molecule was significantly enhanced on equine uterine neutrophils but downregulated on bovine cells. Compared with untreated autologous peripheral neutrophils, both uterine and in vitro migrated neutrophils showed no alteration of phagocytic capacity. The ability to generate reactive oxygen species (ROS) was significantly upregulated in bovine and equine uterine neutrophils. This was also observed after in vitro migration of equine neutrophils, whereas ROS generation by bovine neutrophils was significantly depressed. In summary, the concept of inducing endometritis directly by local application of human interleukin-8 has been reliably successful in cows and mares. The model permits the analysis of PMN migration into the uterus under defined and controlled conditions. The observed differences between cows and mares with respect to phenotypical and functional characteristics of in vivo attracted uterine cells point to species-related features of neutrophil migration. In vitro transmigrated bovine and equine cells partially differ in phenotype and function from uterine neutrophils. Therefore, the in vitro transmigration assay cannot completely represent the in vivo endometritis model described here.

Blood and intrauterine leukocyte profile and function in dairy cows that spontaneously recovered from postpartum endometritis

The profile and function of blood and uterine leukocytes were evaluated in 14 dairy cows that spontaneously recovered from postpartum endometritis (mild, n=6 and heavy, n=8; general health not affected). From a minimum of 2 weeks before parturition until 6 weeks postpartum, blood samples were obtained twice weekly for leukocyte counts and leukogram determination and once weekly for flow cytometry assessment of polimorphonuclear neutrophils (PMN) phagocytic capacity and oxidative burst activity. Uterine fluid-stained smears, obtained twice weekly from parturition until fluid was present in the uterus, were used for determination of the percentage of PMN, of phagocytizing PMN (phago-PMN) and of the mean number of phagocyted bacteria per phagocytizing PMN (phagocytic index; PI). Uterine swabs were obtained twice weekly from parturition until 35 days postpartum for bacteriological examination. The time of endometritis diagnosis was similar in cows with mild or heavy endometritis but the latter cows had a significantly longer persistence of the infection and of the isolation of Gram-negative anaerobes from the uterus. However, the effect of group (mild versus heavy) was not significant for all the blood and uterine parameters analysed. The effect of sampling day (within group effect) was significant (p<0.01 to p<0.00001) for all parameters, except for the blood monocyte count and the blood PMN phagocytic capacity, in which only a tendency for significance was observed (p<0.1). The effect of the interaction group x sampling day was significant only for the blood monocyte count. The phago-PMN and the PI were significantly correlated (r=0.70, p<0.001). A significant correlation was also observed between the uterine fluid phago-PMN and the blood PMN oxidative burst activity (r=-0.41, p<0.05). At the spontaneous recovery, the blood PMN oxidative burst activity was significantly higher (p<0.05) and the percentage of intrauterine phago-PMN and the PI were significantly lower (p<0.001 and p<0.01, respectively) than at diagnosis of endometritis. These results suggest that a decrease in blood PMN oxidative burst activity until the first week postpartum could be associated with an increased susceptibility to early postpartum endometritis. The later increase in this parameter as well as the increase in the intrauterine fluid phago-PMN and PI, might favour the spontaneous resolution of endometritis.

Lochial secretions of Escherichia coli- or Arcanobacterium pyogenes-infected bovine uteri modulate the phenotype and the functional capacity of neutrophilic granulocytes

It has been suggested that in cases of puerperal endometritis of cattle infected with Escherichia coli and Arcanobacterium pyogenes, the neutrophils are compromised in their defense capacity or downregulated functionally. In addition to direct bacterial effects, contents of lochial secretions and secreted products of locally activated polymorphonuclear neutrophilic granulocytes (PMNs) may also account for changes in function of freshly immigrating neutrophils. In this study, lochial secretions were obtained from healthy cows and from cows infected by E. coli or A. pyogenes. Separated uterine PMN of infected cows displayed an altered phenotype and function which correlated with the degree of bacterial contamination. Concurrently tested circulating PMN showed no such changes. Infected lochial secretions sterilized by filtration also changed the phenotype of blood PMN. Lochial secretions of healthy cows displayed only minor effects. The effects on PMN function in infected cows varied: ingestion was less affected, whereas generation of reactive oxygen species (ROS) was severely depressed. Concurrently tested purified bacterial products (solubles and fragments) of E. coli and A. pyogenes did not induce the phenotypical and functional changes observed in blood PMN. Since infected lochia also contained high numbers of immigrated and probably activated PMN, the influence of supernatants from phorbol myristate acetate-activated PMN were tested on freshly isolated blood PMN. Such supernatants also increased the expression of certain surface molecules and inhibited the ROS generation. Thus, reduced function and altered phenotypes of PMN which immigrate into the uteri of cows with bacterial endometritis is due not only to interactions with bacteria or bacterial products, but is also to the uterine milieu.