Resistance in horses refers to the ability of equine species to withstand or counteract various external challenges, such as pathogens, parasites, or environmental stressors. This topic encompasses several aspects, including genetic resistance to diseases, the development of antimicrobial resistance, and the mechanisms by which horses can resist parasitic infections. Understanding resistance involves studying the genetic, immunological, and physiological factors that contribute to a horse's ability to cope with these challenges. Research in this area is focused on identifying markers of resistance, exploring breeding strategies for enhancing disease resistance, and evaluating the impact of management practices on resistance development. This page compiles peer-reviewed research studies and scholarly articles that investigate the mechanisms, implications, and management of resistance in equine populations.
Su Y, Zhang Z, Wang L, Zhang B, Su L. subsp. () is one of the important zoonotic and opportunistic pathogens. In recent years, there has been growing evidence that supports the potential role of in severe diseases in horses and other animals, including humans. Furthermore, the clinical isolation and drug resistance rates of have been increasing yearly, leading to interest in its in-depth genomic analysis. In order to deepen the understanding of the characteristics and genomic features, we investigated the genomic islands, mobile genetic elements, virulence and resistance genes, and phenotype of strain ZHZ 211 (ST147), isolat...
Attili AR, Nocera FP, Sisto M, Linardi M, Gigli F, Ngwa VN, Fiorito F, Cerracchio C, Meligrana MCT, Bonacucina E, Cuteri V, De Martino L.To evaluate the frequency of Acinetobacter spp., belonging to both Acinetobacter calcoaceticus-baumannii (ACB) and non-ACB complex, and their antibiotic resistance profiles in veterinary medicine, a three-year (2020-2022) retrospective study was carried out on sick companion animals. Epidemiological data from different clinical canine, feline, and equine samples, were acquired. For each strain, MALDI-TOF MS identification and susceptibility to a panel of 11 antibiotics, by Kirby-Bauer and E-test methods, were performed. Out of 628 bacteriological examinations, 2.5% resulted positive for strain...
Tomal A, Szłapka-Kosarzewska J, Mironiuk M, Michalak I, Marycz K.Equine metabolic syndrome (EMS) is a critical endocrine condition in horses, characterized by hyperinsulinemia, hyperlipidemia, and insulin resistance, posing a significant threat to their health. This study investigates the efficacy of supplementing EMS-affected horses with Arthrospira platensis enriched with Cr(III), Mg(II), and Mn(II) ions using biosorption process in improving insulin sensitivity and glucose tolerance, reducing inflammation, and mitigating obesity-related fat accumulation. Our results demonstrate that Arthrospira supplementation reduces baseline insulin and glucose levels,...
Mozo Vives B, Mainguy-Seers S, Lavoie JP.Salbutamol and hyoscine butylbromide (HBB) are commonly used bronchodilators in horses with severe asthma (SA). Objective: To compare the bronchodilation potency, duration, and adverse effects of salbutamol and HBB in SA. Methods: Six horses in exacerbation of SA. Methods: The effects of inhaled salbutamol (1000 μg) and HBB (150 mg, IV) were compared in a randomized, blinded, crossover experiment. Lung function, intestinal borborygmi and heart rate were assessed before and sequentially until 180 minutes after drug administration, and analyzed with 2-way repeated-measures ANOVA and Dunne...
Laroche N, Grimm P, Julliand S, Sorci G.The use of anthelminthic drugs has several drawbacks, including the selection of resistant parasite strains. Alternative avenues to mitigate the negative effects of helminth infection involve dietary interventions that might affect resistance and/or tolerance by improving host immunity, modulating the microbiota, or exerting direct anthelmintic effects. The aim of this study was to assess the impact of diet on strongyle infection in horses, specifically through immune-mediated, microbiota-mediated, or direct anthelmintic effects. Horses that were naturally infected with strongyles were fed eit...
Gustafsson K, Sykes BW, Verwilghen D, Palmers K, Sullivan S, van Galen G.Trimethoprim-sulfonamide (TMPS) combinations are widely used to treat a range of infectious diseases in horses, but some equine practitioners are reluctant to use them for treatment of both neonatal and older foals. Considering the emergence of increased antimicrobial resistance, the use of protected antimicrobials commonly prescribed to foals should be avoided and alternative first-line therapy considered, where appropriate. This review examines the characteristics and pharmacokinetics of TMPS and its suitability for treatment of foals. Data regarding dosage and route of administration are re...
Charlotte C P, Benoit B, Olivier M L.To evaluate secondary intention wound healing in the horse's limbs when treated with the synthetic epidermis spray (Novacika®, Cohesive S.A.S, France) or with a standard bandaging technique. Methods: Six Standardbred mares were included in the study. Four 2.5 x 2.5 cm full-thickness skin wounds were created on each thoracic limb. Two wounds were located on the dorsoproximal aspect of the cannon bone and the other two at the dorsoproximal aspect of the fetlock. Six hours after creation, wounds were randomly treated with synthetic epidermis spray or standard bandaging. The wounds were assessed ...
Galinelli NC, Bamford NJ, de Laat MA, Sillence MN, Harris PA, Bailey SR.Insulin dysregulation in horses is characterised by hyperinsulinaemia and/or tissue insulin resistance and is associated with increased risk of laminitis. There is growing evidence in other species that dopamine attenuates insulin release from the pancreas; however, this has yet to be examined in horses. The present study aimed to identify whether there are cells capable of producing or responding to dopamine within the equine gastrointestinal mucosa and pancreas. Tissue samples were collected from the stomach, small and large intestines, and pancreas of six mature horses following euthanasia....
Equine asthma (EA) is a respiratory syndrome associated with the increase of different leukocyte populations in the bronchoalveolar lavage fluid (BALF). Its pathogenetic mechanisms remain unclear. This study aimed to evaluate the associations between the mRNA expression of different cytokines in the BALF, different EA subtypes and lung function. Fifteen horses underwent physical examination, airway endoscopy, BALF cytology and lung function testing (8/15). One horse did not have evidence of EA and was used as healthy reference, while the others were classified as affected by neutrophilic or mi...
Pratt-Phillips S.Obesity is an important health concern in horses, along with humans and companion animals. Adipose tissue is an inflammatory organ that alters the insulin-signaling cascade, ultimately causing insulin dysregulation and impaired glucose metabolism. These disruptions can increase the risk of metabolic disease and laminitis in horses and may also impact energy metabolism during exercise. A single bout of exercise, along with chronic exercise conditioning, increases insulin sensitivity and glucose disposal via both contraction- and insulin-mediated glucose uptake pathways. Regular exercise also in...
Merlin A, Larcher N, Vallé-Casuso JC.This study assessed the anthelmintic resistance in strongylid nematodes against commonly used anthelmintic (AH) drugs in a French galloping racehorse stud farm from March to December 2023. Faecal egg count reduction tests (FECRTs) were conducted in three different groups of Thoroughbred yearlings (a group of 6 males, a group of 13 females and a group of 8 females and 3 males) following the new World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines. The efficacy of fenbendazole was tested in two groups once during the monitoring period (in March), the efficacy of iv...
Dube F, Delhomme N, Martin F, Hinas A, Åbrink M, Svärd S, Tydén E.Anthelmintic resistance in equine parasite Parascaris univalens, compromises ivermectin (IVM) effectiveness and necessitates an in-depth understanding of its resistance mechanisms. Most research, primarily focused on holistic gene expression analyses, may overlook vital tissue-specific responses and often limit the scope of novel genes. This study leveraged gene co-expression network analysis to elucidate tissue-specific transcriptional responses and to identify core genes implicated in the IVM response in P. univalens. Adult worms (n = 28) were exposed to 10-11 M and 10-9 M IVM in vitro for 2...
Olivo G, Zakia LS, Ribeiro MG, da Cunha MLRS, Riboli DFM, Mello PL, Teixeira NB, de Araújo CET, Oliveira-Filho JP, Borges AS.Staphylococci are well-known opportunistic pathogens associated with suppurative diseases in humans and animals. Antimicrobial resistance is an emergent threat to humans and animals worldwide. This study investigated the prevalence of methicillin-resistant Staphylococcus spp. (MRS) in hospitalized horses and contacting personnel (veterinarians and staff), and assessed possible interspecies transmission in a teaching veterinary hospital. Nasal swabs from horses (n = 131) and humans (n = 35) were collected. The microorganisms were identified by traditional biochemical tests and genotypic methods...
Gao Y, Packeiser EM, Wendt S, Sekora A, Cavalleri JV, Pratscher B, Alammar M, Hühns M, Brenig B, Junghanss C, Nolte I, Murua Escobar H.Malignant melanomas (MMs) are the abnormal proliferation of melanocytes and are one of the lethal skin cancers in humans, equines, and canines. Accordingly, MMs in companion animals can serve as naturally occurring animal models, completing conventional cancer models. The common constitutive activation of the MAPK and PI3K pathways in MMs has been described in all three species. Targeting the related pathways is considered a potential option in comparative oncologic approaches. Herein, we present a cross-species comparative analysis exposing a set of ten melanoma cell lines (one human, three e...
Racehorses may experience exercise-induced bronchodilation or bronchoconstriction, with potential differences between healthy and asthmatic individuals. Objective: To identify exercise-related lung function variations by oscillometry in racehorses, compare lung function between healthy and mild equine asthma (MEA) horses, assess oscillometry's potential as a predictor of racing fitness. Methods: Prospective case-control clinical study. Methods: Fourteen Thoroughbred racehorses (5 healthy, 9 MEA) underwent a protocol including respiratory oscillometry at rest, exercise with fitness monitoring, ...
Silva JA, Castañares M, Mouguelar H, Valenciano JA, Pellegrino MS.Endometritis, the inflammation of the endometrium, is the leading cause of subfertility in mares, and therefore responsible for major economic losses in the horse industry worldwide. It is generally treated with uterine lavages combined with ecbolic agents and local or systemic antibiotics. However, since antibiotic overuse has been associated with antimicrobial resistance in mares with persistent endometritis, new prevention and treatment alternatives are needed. One such alternative could be the use of probiotic lactic acid bacteria (LAB) isolated from the host. Thanks to their species speci...
Verdenius CY, Slenter IJM, Hermans H, Broens EM, Djajadiningrat-Laanen SC.Ulcerative keratitis is a common ophthalmic disease in horses which can be complicated by microbial infection and requires immediate, accurate treatment to prevent loss of visual function or the eye. Objective: To report the results of microbial cultures, antibiotic susceptibility tests and corneal cytology in horses with ulcerative keratitis presented to a referral clinic, to assess agreement between cytology and culture results, to investigate whether previous topical treatment affected microbial culture results and whether the incidence of antimicrobial resistance changed during the study p...
Abbas G, Bauquier J, Beasley A, Jacobson C, El-Hage C, Wilkes EJA, Carrigan P, Cudmore L, Hurley J, Beveridge I, Nielsen MK, Hughes KJ, Stevenson MA....This study assessed worm control practices used by Australian Thoroughbred farm managers with an online questionnaire survey. The questionnaire comprised 52 questions (close-ended: 44; open-ended: 8) about farm demography and general husbandry practices, farm managers' knowledge of gastrointestinal nematodes (GIN) and their importance, diagnosis, worm control strategies and anthelmintics, anthelmintic resistance (AR) and grazing management. Following the pilot survey, the link for the questionnaire survey was sent to all (n = 657) registered members of the Thoroughbred Breeders Australia on ...
Gravey F, Sévin C, Castagnet S, Foucher N, Maillard K, Tapprest J, Léon A, Langlois B, Le Hello S, Petry S.Klebsiella pneumoniae is a major cause of infections and reproductive disorders among horses, ranked in recent French studies as the sixth most frequently isolated bacterial pathogen in equine clinical samples. The proportion of multidrug-resistant (MDR) K. pneumoniae is therefore significant in a context where MDR K. pneumoniae strains are considered a major global concern by the World Health Organization. Unassigned: In this study, we used a genomic approach to characterize a population of 119 equine K. pneumoniae strains collected by two laboratories specialized in animal health in Normandy...
Melo UP, Ferreira C, Barreto SWM.Respiratory diseases considerably affect equine athletes, being the second most common cause of poor performance. Among these diseases, fungal pneumonia in horses, caused specifically by Aspergillus spp., is relatively rare but potentially fatal. Fungal pneumonia typically affects horses exposed to fungal elements due to environmental factors, immunosuppression, or previous debilitating illnesses. Treatment is complex, with minimal success due to late diagnosis and serious concomitant underlying diseases. The choice of medication depends on the site of infection, the fungal species involved, a...
Sauer FJ, Hellige M, Beineke A, Geburek F.Few case reports describe equine coxofemoral joint osteoarthritis (CFJOA). Objective: To evaluate diagnostic findings and outcome of horses with CFJOA and to provide a score facilitating radiographic assessment. Methods: Retrospective case series. Methods: History, clinical signs, ultrasonographic, radiographic and intra-articular anaesthesia findings, treatments, outcome, and necropsy results of horses with CFJOA presented between 2002 and 2023 were collated. Radiographic findings were categorised to develop a radiographic score which was applied by two masked examiners. Intra- and inter-obse...
Clark BL, Norton EM, Bamford NJ, Randhawa IAS, Kemp KL, McCue ME, Bertin FR, Stewart AJ.Insulin dysregulation (ID) is central to equine metabolic syndrome. There are limited epidemiological studies investigating dynamic testing of ID in ponies. Objective: To evaluate prevalence and risk factors for ID through dynamic testing of hyperinsulinaemia (DHI) and insulin resistance (IR). Methods: Cross-sectional. Methods: Sex, age, breed, height, cresty neck score (CNS), body condition score (BCS), laminitis, HMGA2:c.83G>A genotype and pituitary pars intermedia dysfunction (PPID) status were documented. Dynamic hyperinsulinaemia was diagnosed with an oral sugar test (OST) and IR with an ...
Rendle D, Hughes K, Bowen M, Bull K, Cameron I, Furtado T, Peachey L, Sharpe L, Hodgkinson J.There is a lack of consensus on how best to balance our need to minimise the risk of parasite-associated disease in the individual horse, with the need to limit the use of anthelmintics in the population to preserve their efficacy through delaying further development of resistance. Objective: To develop evidence-based guidelines utilising a modified GRADE framework. Methods: A panel of veterinary scientists with relevant expertise and experience was convened. Relevant research questions were identified and developed with associated search terms being defined. Evidence in the veterinary literat...
Malaluang P, Wagner LH, Cojkic A, Spergser J, Aurich C, Morrell JM.The presence of bacteria poses a significant challenge to the quality of stallion semen used in artificial insemination. The bacterial content of insemination doses arises from various sources, such as the healthy stallion, environment, and collection equipment, and is implicated in fertility problems as well as reduced sperm quality during storage. The conventional approach of adding antibiotics to semen extenders raises concerns about antimicrobial resistance and potential negative effects on sperm characteristics, and may not be effective in inhibiting all bacteria. The objective of this st...
Pimenta J, Dias C, Cotovio M, Saavedra MJ.Considering the increasing antibiotics resistance, there has been a propensity to replace them with antiseptics when it comes to wound management and treatment. Nevertheless, in recent years, there have been reports regarding resistance to antiseptics by some bacterial strains. There is also concern about the environmental impact of these substances. The aim of this study was to compare the antimicrobial efficacy of antiseptics and eucalyptus essential oils on bacterial strains from horse's wounds. We used twelve Escherichia coli, eight Staphylococcus aureus, two Staphylococcus pseudintermediu...
Bourebaba L, Kępska M, Qasem B, Zyzak M, Łyczko J, Klemens M, Mularczyk M, Marycz K.Equine metabolic syndrome (EMS) is a steadily growing endocrine disorder representing a real challenge in veterinary practice. As a multifactorial condition, EMS is characterized by three main metabolic abnormalities including insulin resistance, increased adiposity or obesity and hoof laminitis. Adipose tissue dysfunction is recognized as a core pathophysiological determinant of EMS, as it strongly participates to lipotoxicity and systemic metaflammation, both of which have been closely linked to the development of generalized insulin resistance. Besides, sex hormone binding globulin (SHBG) i...
Abbas G, Ghafar A, McConnell E, Beasley A, Bauquier J, Wilkes EJA, El-Hage C, Carrigan P, Cudmore L, Hurley J, Gauci CG, Beveridge I, Ling E....This study quantified the extent of anthelmintic resistance (AR) in ascarid and strongylid nematodes against commonly used anthelmintics in Australian Thoroughbred horses. Faecal egg count reduction tests (FECRTs, n = 86) and egg reappearance period (ERP) tests were conducted on 22 farms across Australia. Faecal egg counts (FECs) were determined using the modified McMaster technique, and percent faecal egg count reduction (%FECR) was calculated using the Bayesian hierarchical model and hybrid Frequentist/Bayesian analysis method. The results were interpreted using old (published in 1992) and...
Rockow M, Griffenhagen G, Landolt G, Hendrickson D, Pezzanite L.Recognition of antimicrobial resistance in equine practice has increased over the past decade. The objective of this study was to provide an updated retrospective review of antimicrobial regimens in one tertiary referral hospital and to evaluate the association with postoperative complications. A secondary objective was to evaluate other perioperative factors including surgical procedure, anesthetic and recovery parameters, and the effect of perioperative medications on complications and outcomes. A computerized search of medical records was performed to identify horses undergoing exploratory ...
Hedberg Alm Y, Halvarsson P, Martin F, Osterman-Lind E, Törngren V, Tydén E.Consisting of approximately 50 different species, the cyathostomin parasites are ubiquitous in grazing horses. Co-infection with several species is common, and large burdens can cause the fatal disease of larval cyathostominosis. Due to intense anthelmintic drug use, cyathostomin resistance has developed to all available anthelmintic drug groups. Resistance to the anthelmintic drug pyrantel (PYR) has been documented in over 90% of studies published over the past two decades. In Sweden, a study performed in the early 2000s only confirmed resistance in 4.5% of farms. Further, prescription-only a...
Westerfeld R, Payette F, Dubuc V, Manguin E, Picotte K, Beauchamp G, Bédard C, Leclere M.Reducing inhaled dust particles improves lung function in horses with severe asthma. Soaked hay is commonly used by owners, but its efficacy in improving lung function and inflammation has not been documented. Objective: To measure the effects of soaked hay and alfalfa pellets in horses with severe asthma. Methods: Ten adult horses with severe asthma from a research colony. Methods: Prospective controlled trial. Horses in clinical exacerbation were housed indoors and allocated to be fed either soaked hay (n = 5) or alfalfa pellets (n = 5) for 6 weeks. Soaked hay was immersed for 45...
Burton AJ, Giguère S, Sturgill TL, Berghaus LJ, Slovis NM, Whitman JL, Levering C, Kuskie KR, Cohen ND.Macrolide and rifampin resistance developed on a horse breeding farm after widespread use was instituted for treatment of subclinical pulmonary lesions in foals. Resistance occurred in 6 (24%) of 25 pretreatment and 8 (62%) of 13 (62%) posttreatment isolates from affected foals. Drug-resistant isolates formed 2 distinct genotypic clusters.
Huber L, Giguère S, Slovis NM, Carter CN, Barr BS, Cohen ND, Elam J, Erol E, Locke SJ, Phillips ED, Smith JL.The objective of this study was to determine the prevalence of strains resistant to macrolides and rifampin over time in clinical samples from foals submitted to diagnostic laboratories in central Kentucky. We performed a retrospective observational study of all clinical samples from foals that were submitted to veterinary diagnostic laboratories in Kentucky between January 1995 and December 2017. Samples were included if the bacterium was cultured and tested for susceptibility to erythromycin or rifampin. susceptibility testing to erythromycin was available for 2,169 isolates of , while s...
Cordeiro Rde A, de Oliveira JS, Castelo-Branco Dde S, Teixeira CE, Marques FJ, Bittencourt PV, Carvalho VL, Bandeira Tde J, Brilhante RS, Moreira JL....Candida tropicalis has been associated with invasive candidiasis, being the first or second most common non-Candida albicans Candida species isolated in humans with candidemia and candiduria, as well as being frequently isolated from healthy animals. This study aimed to characterize C. tropicalis isolates (n = 64) obtained from several animal species regarding antifungal susceptibility and production of virulence factors. The isolates were obtained from the microbiota of healthy animals (goats, n = 25; sheep, n = 6; psittacines, n = 14; rheas, n = 6; horses, n = 2; sirenians, n = 5; shrimp, n ...
Kamran K, Ali A, Villagra CA, Bazai ZA, Iqbal A, Sajid MS.Ivermectin and fipronil have been used regularly to control the hard tick Hyalomma anatolicum (Acari: Ixodidae) in domestic ruminants for more than a half-decade in Balochistan, Pakistan. Inappropriate and indiscriminate use of these acaricides has resulted in the development of resistances in tick species. In this work, acaricides (ivermectin and fipronil) resistance was evaluated in H. anatolicum through in vitro and in vivo bioassays in a horse farm of Quetta, Balochistan province, Pakistan. A participatory epidemiological survey was conducted to assess potential risk factors associated wit...
Johnson PJ, Wiedmeyer CE, LaCarrubba A, Ganjam VK, Messer NT.Although much has been written about laminitis in the context of its association with inflammatory processes, recognition is growing that most cases of laminitis examined by veterinarians in private practice are those associated with pasture grazing, obesity, and insulin resistance (IR). The term 'endocrinopathic laminitis' has been adopted to classify the instances of laminitis in which the origin seems to be more strongly associated with an underlying endocrinopathy, such as either IR or the influence of corticosteroids. Results of a recent study suggest that obesity and IR represent the mos...
Castagnolli KC, de Figueiredo LB, Santana DA, de Castro MB, Romano MA, Szabó MP.Acquired immunity of horses to larvae, nymphs and adults of the Amblyomma cajennense tick was evaluated through three consecutive experimental infestations of tick-bite naïve hosts. Data from these infestations were compared to those from field-sensitized horses and donkeys. It was observed that tick-bite naïve horses developed a low level of resistance after two infestations as shown by a significant decrease in larval yield and a tendency for lower engorged weight of nymphs during third infestation. Ticks fed on field-sensitized horses had a similar biological performance to that observed ...
Fines M, Pronost S, Maillard K, Taouji S, Leclercq R.Treatment with a combination of erythromycin and rifampin has considerably improved survival rates of foals and immunocompromised patients suffering from severe pneumonia caused by Rhodococcus equi. Frequently, because of monotherapy, emergence of rifampin-resistant strains has been responsible for treatment failure. Using consensus oligonucleotides, we have amplified and sequenced the rifampin resistance (Rif(r))-determining regions of 12 rifampin-resistant R. equi strains isolated from three foals and of mutants selected in vitro from R. equi ATCC 3701, a rifampin-susceptible strain. The ded...
Buckley T, McManamon E, Stanbridge S.This study sought to determine whether an increase in resistance of Rhodococcus equi to the antibiotics rifampin and erythromycin occurred over a 10-year period. This was carried out by the use of E test strips for rifampin and erythromycin to determine the MIC (minimum inhibitory concentration) values of Rhodococcus equi to this combination of antibiotics.The findings of this study indicated that there was an increase in resistance of Rhodococcus equi to rifampin and erythromycin over the 10-year period. The MIC for rifampin increased from 0.081 μg/ml in 1996 to 0.187 μg/ml in 2006 and from...
Taylor MA, Hunt KR.The term 'anthelmintic drug resistance' describes the heritable ability of some nematode parasites to survive treatment with anthelmintic drugs at the recommended therapeutic dose levels. Genes for resistance appear to be present in many of the important pathogenic nematodes of ruminants and horses. Under intensive management systems, where heavy reliance is placed on anthelmintic drugs for worm control, the selection of resistant genotypes may result in increased reports of the drugs failing to control the nematode populations against which they are aimed. Anthelmintic resistance has been rep...
Rasheed H, Ijaz M, Ahmed A, Javed MU, Shah SFA, Anwaar F.Antimicrobial resistance is a global issue that limits therapeutic options for infections. S. aureus being a member of the ESKAPE group is capable of "escaping" the biocidal action of antimicrobial agents. There are phenotypic and genotypic methods used for the identification of antibiotic resistant genes harboring S. aureus but these methods do not always show concordant results. To address these discrepancies, a total of 335 equine nasal swab samples from four districts of Punjab were collected using a convenient sampling technique. These samples were first subjected to common microbial tech...
Abbas G, Ghafar A, McConnell E, Beasley A, Bauquier J, Wilkes EJA, El-Hage C, Carrigan P, Cudmore L, Hurley J, Gauci CG, Beveridge I, Ling E....This study quantified the extent of anthelmintic resistance (AR) in ascarid and strongylid nematodes against commonly used anthelmintics in Australian Thoroughbred horses. Faecal egg count reduction tests (FECRTs, n = 86) and egg reappearance period (ERP) tests were conducted on 22 farms across Australia. Faecal egg counts (FECs) were determined using the modified McMaster technique, and percent faecal egg count reduction (%FECR) was calculated using the Bayesian hierarchical model and hybrid Frequentist/Bayesian analysis method. The results were interpreted using old (published in 1992) and...
Carlson KL, Kuskie KR, Chaffin KM, Libal MC, Giguère S, Lawhon SD, Cohen ND.This study determined the antimicrobial activity of tulathromycin against Rhodococcus equi in vitro. Ninety-eight virulent isolates of R. equi from equine clinical cases were examined, of which 20 isolates were macrolide resistant. A custom 96-well antimicrobial susceptibility testing plate was used, allowing 14 additional antimicrobials to be tested against R. equi. Isolates were cultured with various concentrations of antimicrobials, and minimal inhibitory concentration (MIC) values were determined. Tulathromycin was found to have poor activity in vitro against R. equi isolates susceptible o...
Val-Calvo J, Darcy J, Gibbons J, Creighton A, Egan C, Buckley T, Schmalenberger A, Fogarty U, Scortti M, Vázquez-Boland JA.A multidrug-resistant clone of the animal and human pathogen Rhodococcus equi, MDR-RE 2287, has been circulating among equine farms in the United States since the 2000s. We report the detection of MDR-RE 2287 outside the United States. Our finding highlights the risk for MDR-RE spreading internationally with horse movements.
Feary DJ, Hyatt D, Traub-Dargatz J, Roach S, Jones RL, Wu CC, Morley PS.The objective of this study was to investigate the perceived increase in resistance of Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) isolated from the lower respiratory tract of horses to trimethoprim-sulfamethoxazole (SXT). The recorded SXT-susceptibility results of 50 S. zooepidemicus isolates from the tracheal wash fluid of equine patients examined at Colorado State University Veterinary Teaching Hospital from each of 2 time periods (1987-1990 and 1997-2001) were compared and statistically analyzed using a cross-sectional study design. There was a statistically significant diff...
Lejeune M, Mann S, White H, Maguire D, Hazard J, Young R, Stone C, Antczak D, Bowman D.The American Association of Equine Practitioners strongly advocates evidence-based intestinal strongyle control in horses. It recommends targeted treatment of all heavy egg shedders (>500 eggs per gram (EPG) of feces), while the low shedders (0-200 EPG) are left untreated. As 50-75% of adult horses in a herd are low shedders, preventing them from unnecessary anthelmintic exposure is critical for tackling resistance. There are various fecal egg count (FEC) techniques with many modifications and variations in use, but none is identified as a gold standard. The hypothesis of the study was that...
Petry S, Sévin C, Kozak S, Foucher N, Laugier C, Linster M, Breuil MF, Dupuis MC, Hans A, Duquesne F, Tapprest J.Study of the rifampicin resistance of Rhodococcus equi strains isolated from French horses over a 20-year period. Rifampicin susceptibility was tested by disk diffusion (DD) and broth macrodilution methods, and rpoB gene sequencing and MLST were performed on 40 R. equi strains, 50.0% of which were non-susceptible to rifampicin. Consistency of results was observed between rifampicin susceptibility testing and rpoB sequencing. Strains non-susceptible to rifampicin by DD had a substitution at one of the sites (Asp516, His526 and Ser531) frequently encountered and conferring rifampicin resistance....
Bourebaba L, Serwotka-Suszczak A, Bourebaba N, Zyzak M, Marycz K.Hyperactivation of protein tyrosine phosphatase (PTP1B) has been associated with several metabolic malfunctions ranging from insulin resistance, metaflammation, lipotoxicity, and hyperglycaemia. Liver metabolism failure has been proposed as a core element in underlying endocrine disorders through persistent inflammation and highly fibrotic phenotype. Unassigned: In this study, the outcomes of PTP1B inhibition using trodusquemine (MSI-1436) on key equine metabolic syndrome (EMS)-related alterations including inflammation, fibrosis, and glucose uptake have been analyzed in liver explants collect...
Bourebaba L, Kępska M, Qasem B, Zyzak M, Łyczko J, Klemens M, Mularczyk M, Marycz K.Equine metabolic syndrome (EMS) is a steadily growing endocrine disorder representing a real challenge in veterinary practice. As a multifactorial condition, EMS is characterized by three main metabolic abnormalities including insulin resistance, increased adiposity or obesity and hoof laminitis. Adipose tissue dysfunction is recognized as a core pathophysiological determinant of EMS, as it strongly participates to lipotoxicity and systemic metaflammation, both of which have been closely linked to the development of generalized insulin resistance. Besides, sex hormone binding globulin (SHBG) i...
Spier SJ, Berger Pusterla J, Villarroel A, Pusterla N.Behavioural reactions to selected handling procedures were compared between conditioned, or imprint-trained, and untrained foals raised on the same farm. Nineteen randomly chosen healthy foals were imprint trained at birth and 24 h later (Group A). Twenty-one similar foals that were not imprint-trained served as age-matched controls (Group B). Training began within 10 min of birth and consisted of touch desensitization by gentle rubbing. Each tactile stimulus was repeated 30-50 times over 45-60 min, until the foal no longer resisted the procedure and appeared relaxed. The procedure was then re...
Fenton CS, Buckley TC.Rhodococcus equi is a gram positive, intracellular pathogen of foals worldwide. The aim of this study was to determine whether there was an increasing resistance occurring in Rhodococcus equi towards the antibiotics rifampin and erythromycin over a seven year period. The investigation was carried out with the use of E test strips (epsilometers) for rifampin and erythromycin in order to determine the Minimum Inhibitory Concentrations (MIC) values of Rhodococcus equi to these antibiotics. Results: The main results of this study found that the mean MICs were higher for erythromycin than for rifam...
Drogemuller M, Schnieder T, von Samson-Himmelstjerna G.P-glycoproteins (Pgps) are adenosine triphosphate-binding transporter proteins thought to be associated with multi-drug resistance in mammals and protozoans and have been suggested to be involved in the mechanism of ivermectin (IVM) resistance in Haemonchus contortus. Until now, resistance to IVM has not been reported in cyathostomins in horses in spite of its widespread and frequent use. Reasons for this might be differences in the molecular mechanism of the development of resistance. Based on this hypothesis, the present study was carried out to find homologues of Pgp in cyathostomins. A 416...
Silva JA, Castañares M, Mouguelar H, Valenciano JA, Pellegrino MS.Endometritis, the inflammation of the endometrium, is the leading cause of subfertility in mares, and therefore responsible for major economic losses in the horse industry worldwide. It is generally treated with uterine lavages combined with ecbolic agents and local or systemic antibiotics. However, since antibiotic overuse has been associated with antimicrobial resistance in mares with persistent endometritis, new prevention and treatment alternatives are needed. One such alternative could be the use of probiotic lactic acid bacteria (LAB) isolated from the host. Thanks to their species speci...
Ellse L, Burden F, Wall R.Equine pediculosis is a significant health and welfare issue, particularly in elderly and chronically debilitated animals. Currently infestation is controlled predominantly using topically applied pyrethroid insecticides, allowing limited scope for the rotation of drugs and increasing the risk of selection for resistance. Here the insecticidal efficacies of two pyrethroid-based products against the louse Bovicola (Werneckiella) ocellatus collected from donkeys were examined in vitro. The products were cypermethrin (Deosect™, Pfizer Ltd., 5% (w/v) cypermethrin, cutaneous spray) and permethrin...
Orsini JA, Benson CE, Spencer PA, Van Miller E.Resistance of gram-negative bacteria to gentamicin has become an increasingly common problem among clinical isolates from human beings. Susceptibility of isolates from horses to gentamicin and amikacin was evaluated for the period from July, 1983 to June, 1985. All isolates of Escherichia coli, and species of Enterobacter, Klebsiella, Proteus, and Pseudomonas examined were susceptible to amikacin, except 2 of the 46 Pseudomonas isolates. In contrast, 13 to 50% of isolates were resistant to gentamicin. Escherichia coli, and Klebsiella, Proteus, and Enterobacter species isolates were highly sign...
Matthews JB, Peczak N, Lightbody KL.Helminths are commonly found in grazing equids, with cyathostomin nematodes and the cestode being the most prevalent. Most horses harbour low burdens of these parasites and do not develop signs of infection; however, in a small number of animals, high burdens can accumulate and cause disease. Cyathostomins are associated with a syndrome known as larval cyathostominosis. This occurs when large numbers of larvae emerge from the large intestinal wall. This disease has a case fatality rate of up to 50%. infection has been associated with various types of colic, with burdens of >20 worms assoc...
Hedberg Alm Y, Halvarsson P, Martin F, Osterman-Lind E, Törngren V, Tydén E.Consisting of approximately 50 different species, the cyathostomin parasites are ubiquitous in grazing horses. Co-infection with several species is common, and large burdens can cause the fatal disease of larval cyathostominosis. Due to intense anthelmintic drug use, cyathostomin resistance has developed to all available anthelmintic drug groups. Resistance to the anthelmintic drug pyrantel (PYR) has been documented in over 90% of studies published over the past two decades. In Sweden, a study performed in the early 2000s only confirmed resistance in 4.5% of farms. Further, prescription-only a...
Rendle D, Hughes K, Bowen M, Bull K, Cameron I, Furtado T, Peachey L, Sharpe L, Hodgkinson J.There is a lack of consensus on how best to balance our need to minimise the risk of parasite-associated disease in the individual horse, with the need to limit the use of anthelmintics in the population to preserve their efficacy through delaying further development of resistance. Objective: To develop evidence-based guidelines utilising a modified GRADE framework. Methods: A panel of veterinary scientists with relevant expertise and experience was convened. Relevant research questions were identified and developed with associated search terms being defined. Evidence in the veterinary literat...
