Pre- or perioperative antibiotic prophylaxis in horses undergoing aseptic, elective orthopaedic surgery

This dissertation comprises a retrospective analysis of patient files and a randomised, prospective clinical study of postoperative complications in equines after clean orthopaedic surgical procedures. The main aim of these studies was to evaluate possible differences between horses pre-treated with antibiotics and those not having received these drugs. For the retrospective part, 652 out of the 684 case files were suitable for statistical analysis. Details were compiled on the patients, the surgical procedure, and the surgery-associated complications. Antibiotic-receiving patients (n=259) were statistically compared to controls (n=393) by employing the Fisher-Freeman-Halton test or an ANOVA. The main parameter was the development of postoperative complications. For the post hoc analysis, Fisher’s exact test and the Wilcoxon-Mann-Whitney-test were used. The overall complication rate in the retrospective study was 39.1%. An increased incisional swelling was observed most often (25.6%), followed by exudation (7.5%), fever (2.3%), dehiscence (1.8%), and seroma in five cases (0.8%). Septic arthritis was documented in 7/463 horses (1.5%) undergoing arthroscopies. There were no significant differences detected in the development of postoperative complications between the 97/259 (37.5%) antibiotic-receiving patients and in the 158/393 (40.2%) controls. The application of perioperative antibiotics was significantly influenced by the surgeon (p<0.0001), type of surgery (p=0.0007), and increased with the number of surgical lesions (p=0.03). Antibiotic-receiving patients were treated for 3-5 days after surgery and most of them received penicillin-based antibiotics. Patients with three or more interventions per session (n=30) received antibiotics significantly more often. In patients undergoing tendovaginoscopy/bursoscopy, fasciotomy, and neurectomy (n=98), antibiotic prophylaxis was initiated less frequently than in the other surgeries, e.g., combinations of surgeries, splint bone extraction, tenotomy, and arthroscopy (n=554). In the prospective clinical study, 75 horses were assigned randomly to either the antibiotic-receiving (treated) or the control group. Treated horses received 10 mg/kg amoxicillin and 6.6 mg/kg gentamicin once directly before inducing general anaesthesia. These horses were intensely monitored for five days. Using a semiquantitative scoring system for swelling, skin temperature, exudation, and dehiscence, the surgical wounds were assessed on the days one, three, and five after surgery. In addition, the inflammatory parameters SAA, iron, and haptoglobin were determined on the day before, directly after, and on days one three and five after the surgery. Differences between the groups in score points, rectal body temperature, concentrations of inflammatory parameters, and patient characteristics were tested by the Fisher-Freeman-Halton test or the ANOVA/Wald test. For the post hoc analysis, Fisher’s exact test and the Wilcoxon-Mann-Whitney test were used. Total score (p=0.002), the scores for swelling (p=0.002), and skin temperature (p=0.007) were significantly higher in the treated group than in controls. The post hoc analysis identified a significantly higher total score for the treated horses on day 1 (p=0.02), and 5 (p=0.01), which was mainly due to swelling with significantly higher scores on days 1 (p=0.02) and 5 (p=0.002), too. On day 1 (p=0.04) and 3 (p=0.03), the score points for skin temperature were significantly higher in the treated horses. Four horses in the control group and just one treated developed fever. There was no significant difference between the groups in SAA (p=0.18), serum iron (p=0.76), and haptoglobin (p=0.85) concentrations. Two horses (1 control, 1 treated drop-out), of which the treated one dropped out of the study because of postoperative additional gentamicin administration, developed a septic joint eight and nine days after surgery, respectively. Such severe complications in equine clean orthopaedic surgery are rare, whether having received perioperative antibiotics or not. In summary, the use of perioperative antibiotic prophylaxis in uncomplicated, elective orthopaedic surgical procedures in equines cannot be justified based on these data.Dieses Dissertationsprojekt beinhaltet eine retrospektive Analyse und eine randomisierte, prospektive klinische Studie zu postoperativen Komplikationen bei Pferden nach sauberen, elektiven orthopädischen Eingriffen. Ziel beider Studien war es zu untersuchen, ob Unterschiede zwischen antibiotisch (vor-)behandelten und nicht mit Antibiotika behandelten Tieren (Kontrolle) hinsichtlich der Entwicklung postoperativer Komplikationen bestehen. Für den retrospektiven Teil konnten aus 684 Patientenakten 652 Fälle eingeschlossen werden. Einzelheiten zum Signalement, chirurgischen Eingriffen und OP-assoziierten Komplikationen wurden extrahiert. Mittels Fisher-Freeman-Halton-Test oder ANOVA wurde statistisch geprüft, ob Unterschiede zwischen mit Antibiotika behandelten Patienten (n=259) und Kontrollen (n=393) bestanden. Als post-hoc Tests wurden Fisher’s Exact Test und der Wilcoxon-Mann-Whitney Test verwendet. Insgesamt traten bei 39,1% der Pferde in der retrospektiven Studie postoperative Komplikationen auf. Vermehrte Schwellung (25,6%) war die häufigste Komplikation, gefolgt von Exsudation (7,5%), Fieber (2,3%), Dehiszens (1,8%), septischer Arthritis [bei 463 arthroskopierten Patienten (1,5%)] und einem Serom, das bei fünf Patienten auftrat (0,8%). Signifikante Unterschiede in den OP-assoziierten Komplikationen zwischen antibiotisch behandelten Patienten (97/259) und Kontrollen (158/393) wurden nicht nachgewiesen. Die Gabe von perioperativen Antibiotika wurde signifikant vom Chirurgen (p>0,0001), der Art der Operation (p=0,0007) und der Anzahl chirurgischer Eingriffe pro Sitzung beeinflusst (p=0,03). Mit Antibiotika behandelte Pferde erhielten 3-5 Tage lang Antibiotika. Am häufigsten wurden Penicillin-basierte Wirkstoffe eingesetzt. Patienten mit drei oder mehr Eingriffen (n=30) erhielten signifikant häufiger Antibiotika. Perioperative Antibiotika wurden seltener bei Tendovaginoskopie/Bursoskopie, Fasziotomie und Neurektomie (n=98) als bei Kombinationen von Eingriffen, Griffelbeinextraktionen, Desmotomie und Arthroskopie (n=554) gegeben. Für die prospektive Studie wurden 75 Pferde, die für einen elektiven orthopädischen EIngriff in der Klinik vorgestellt wurden, randomisiert entweder der Antibiotika-Gruppe oder der Kontroll-Gruppe zugeordnet. Antibiotisch behandelte Pferde erhielten einmalig 10 mg/kg Amoxicillin und 6,6 mg/kg Gentamicin vor der Einleitung der Narkose. Diese 75 Pferde wurden über 5 Tage intensiv überwacht. Mittels eines Scores wurden Schwellung, Hauttemperatur, Exsudation und Dehiszens am ersten, dritten und fünften Tag nach dem Eingriff beurteilt. Zusätzlich wurden am Tag vor, direkt nach sowie einen, drei und fünf Tage nach der Operation die Entzündungsparameter SAA, Eisen und Haptoglobin bestimmt. Die beiden Patientengruppen wurden auf Unterschiede in den Scorepunkten, Körpertemperatur, Konzentrationen der Entzündungsparameter und Patientencharakteristika mit dem Freeman-Halton-Test oder ANOVA/Wald-Test geprüft. Als post-hoc-Tests wurden Fisher’s Exact Test und der Wilcoxon-Mann-Whitney-Test verwendet. Der Gesamtscore (p=0.002), die Scores für Schwellung (p=0.002) und Hauttemperatur (p=0.007) der antibiotisch behandelten Tiere waren signifikant höher als bei den Kontrollen. In der Post-hoc Analyse war der Gesamtscore bei behandelten Tieren an Tag 1 (p=0.02) und fünf (p=0.01) signifikant höher als bei den Kontrollen, ebenso wie der Score für Schwellung an Tag 1 (p=0.02) und 5 (p=0.002), sowie der Score für Hauttemperatur an Tag 1 (p=0.04) und 3 (p=0.03). Weder in der SAA- (p=0.18), noch in der Eisen- (p=0.76) oder Haptoglobin-Konzentration (p=0.85) gab es signifikante Unterschiede zwischen den Gruppen. Zwei Pferde (1 Kontrolle, 1 Drop-out) entwickelten ein septisches Hufgelenk. Das ausgeschlossene antibiotisch behandelte Pferd entwickelte an Tag 9 nach dem Eingriff ein septisches Hufgelenk trotz einer zusätzlichen Behandlung mit Gentamicin an Tag 1 und 2. Bei dem Kontrollpatienten trat die septische Arthritis an Tag 8 auf. Schwere postoperative Komplikationen bei sauberen orthopädischen Eingriffen beim Pferd sind selten. Die Inzidenzen schwerer Komplikationen bei Patienten mit und ohne perioperative Antibiose unterschieden sich nicht statistisch signifikant. Zusammenfassend lässt sich anhand der vorliegenden Daten ein grundsätzlicher Einsatz von Antibiotika bei unkomplizierten, elektiven orthopädischen Eingriffen beim Pferd nicht rechtfertigen

Diagnostic orientation values for ACTH and other parameters for clinically healthy donkeys and mules (insulin, triglycerides, glucose, fructosamines, and ɣ‐GT)

Pituitary pars intermedia dysfunction is the most prevalent endocrine disease in horses. Although donkeys and mules may also be affected, only a few data have been published. Reference values for diagnostic parameters, such as adrenocorticotropic hormone (ACTH), are especially scarce or even lacking. Therefore, in the present study, available data from the literature have been verified and completed to facilitate a reliable diagnosis. Clinical inspections and haematological and biochemical examinations were carried out four times in a three‐month interval (February to November) in 44 donkeys and 31 mules. Data from clinically healthy animals were used as an orientation. Plasma ACTH concentrations showed seasonal changes in both animal groups. However, it was generally higher in donkeys than mules. Although blood glucose (EDTA plasma) showed no difference between groups, serum insulin concentrations were consistently higher in donkeys. Serum fructosamine levels were slightly higher in mules, whereas, in some cases, serum triglyceride levels were considerably higher in donkeys. Serum gamma‐glutamyltransferase showed a striking peak in mules in August, whereas the remaining gamma‐glutamyltransferase values were lower compared to donkeys. By comparing donkeys and mules, the present work reveals differences in various blood parameters which should be considered for diagnoses and future studies

Pituitary Pars Intermedia Dysfunction and Metabolic Syndrome in Donkeys

Appropriate medical care for donkeys is challenging despite being important working animals in non-industrialized countries and pets in first world countries. Although the same principles of diagnosis and therapy as in horses are commonly applied, there are differences in reference values and physiologic reaction to dynamic tests. However, donkeys seem to suffer from typical equine diseases, such as metabolic syndrome and pituitary pars intermedia dysfunction (PPID). Asinine metabolic syndrome (AMS) comprises obesity, insulin dysregulation, and laminitis. The principles of diagnosis are similar to horses. Donkey-specific reference ranges for insulin and glucose have been evaluated previously. Examinations regarding dynamic testing revealed differences in the intravenous glucose tolerance test and the combined insulin tolerance test compared to horses. The therapy of AMS is based mainly on weight loss and exercise. There are conflicting data regarding the incidence of PPID in donkeys. Laminitis and hypertrichosis were described as the main clinical signs. Species-specific and seasonal reference ranges were defined to diagnose PPID in donkeys. Furthermore, the dexamethasone suppression test, the thyrotropin releasing hormone (TRH) test and the combined dexamethasone suppression/TRH test were evaluated. Pergolide is commonly recommended for treatment

Seroprevalence of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum Infections in German Horses

There are limited data on Lyme borreliosis (LB), a tick-borne disease caused by the Borrelia burgdorferi sensu lato complex, in horses. Seropositivity is not necessarily associated with clinical disease. Data on seropositivity against Borrelia burgdorferi and Anaplasma phagocytophilum in German horses are sparse. Therefore, serum samples from horses (n = 123) suspected of having Lyme borreliosis and clinically healthy horses (n = 113) from the same stables were tested for specific antibodies against Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum. The samples were screened for antibodies against Borrelia burgdorferi (ELISA and an IgG line immunoblot assay). Furthermore, the samples were examined for antibodies against B. burgdorferi and Anaplasma phagocytophilum with a validated rapid in-house test (SNAP® 4Dx Plus® ELISA). The clinical signs of suspect horses included lameness (n = 36), poor performance (n = 19), and apathy (n = 12). Twenty-three percent (n = 26) of suspect horses and 17% (n = 18) of clinically healthy horses were seropositive for having a Borrelia burgdorferi sensu lato infection (p = 0.371), showing that the detection of specific antibodies against B. burgdorferi alone is not sufficient for a diagnosis of equine LB. Anaplasma phagocytophilum seropositivity and seropositivity against both pathogens was 20%/6% in suspect horses and 16%/2% in the clinically healthy population, showing only minor differences (p = 0.108). Unspecific testing for antibodies against B. burgdorferi without clinical suspicion of Lyme borreliosis is not recommended since the clinical relevance of seropositivity against Borrelia burgdorferi sensu lato remains to be elucidated

Auswirkungen von Endokrinopathien auf das Plasma-Aminosäureprofil von Pferden

Horses suffering from laminitis usually have an underlying endocrine disease such as equine metabolic syndrome or a dysfunction of the pituitary gland (pitiutary pars intermedia dysfunction = PPID). Hyperinsulinaemia, which is caused by insulin-dysregulation, is currently assumed to be the triggering factor for laminitis. Insulin-dysregulation is present in equine metabolic syndrome and can also occur in horses suffering from PPID. It has already been shown that experimentally induced hyperinsulinaemia causes a change in the plasma amino acid profile of horses. This project was divided into 2 sub-projects. In the first sub-project, the plasma amino acid concentration of horses suffering from PPID was compared with that of healthy horses. Therefore, EDTA-plasma of horses from horses that were presented at the Equine Clinic of the Freie Universität Berlin for different reasons and required laboratory tests of blood anticoagulated with EDTA was asserved. This plasma was used to determine the basal ACTH concentration as well as the amino acid profile. Horses were considered to have PPID if the ACTH concentration was ≥ 100 pg/ml, i.e. they were considered to have PPID at any time. Horses were defined as healthy (nPPID) if the ACTH concentration was below 30 pg/ml, so they were considered healthy at any time point. Horses that received pergolide and whose ACTH concentration was ≤ 30 pg/ml were assigned to the PPIDrr group (PPID, ACTH in the reference range) and horses that received pergolide and whose ACTH concentration was ACTH ≥ 100 pg/ml were assigned to the PPIDarr group (PPID, ACTH above the reference range). A total of 93 horses were examined, 88 of them in the clinic and 5 in a private practice. Of these, 53 horses met the inclusion criteria (ACTH ≤ 30 pg/ml or ACTH ≥ 100 pg/ml). 25 horses were diagnosed as nPPID, 20 as PPID, 5 as PPIDrr and 3 as PPIDarr. No significant differences were present between the groups in terms of sex and breed. However, significant differences were found between groups with respect to feeding, age and ACTH concentration. Significant differences were present between nPPID and PPIDrr and PPID and PPIDrr with respect to feeding: All horses identified as PPIDrr were fed hay only, whereas the nPPID and PPID patients were fed concentrates (1 nPPID), mash (10 nPPID, 3 PPID) or grass (1 nPPID, 12 PPID) in addition to hay. One horse (nPPID) received only grass. In addition, horses suffering from PPID were significantly older than nPPID horses. There were no significant differences in age between the other groups. There were no significant differences in ACTH concentration between nPPID and PPIDrr. The ACTH concentration of PPID patients was significantly higher than in nPPID, PPIDrr and PPIDarr. In addition, PPIDarr horses had significantly higher ACTH concentrations than PPIDrr horses. The following significant differences were present in plasma amino acid concentrations: Arginine was significantly higher in PPIDrr than in PPID and nPPID, asparagine was significantly higher in PPID, PPIDrr and PPIDarr than in nPPID, citrulline was significantly higher in PPIDrr than in nPPID and PPID, cysteine was significantly lower in PPIDrr than in PPID, nPPID and PPIDarr and glutamine was significantly higher in PPID and PPIDarr than in nPPID. In the second part of the project, the plasma amino acid concentration of obese horses with and without chronic laminitis/lean horses suffering from chronic laminitis presented for a combined glucose-insulin-test (CGIT) as well as for a radiographic examination of the hooves. A total of 25 obese horses and two lean horses with recurrent laminitis underwent CGIT. Of the 27 horses that presented, five were non-insulin-dysregulated (obese), 14 were insulindysregulated and eight were insulin-dysregulated with radiographic evidence of chronic laminitis. Significant differences in resting amino acid concentrations were found between obese and insulin-dysregulated laminitis affected horses (citrulline, GABA, methionine). Furthermore, a significant difference between insulin-dysregulated horses with and without laminitis was detected with respect to the plasma GABA concentration. Overall, this project provides interesting approaches to develop further diagnostic tests, especially for the detection of horses at risk of laminitis, and possibly also for research into feed supplements.Bei an Hufrehe leidenden Pferden liegt häufig eine endokrine Grunderkrankung wie beispielsweise das equine metabolische Syndrom oder eine Dysfunktion des Hypophysenzwischenlappens (Pitiutary Pars Intermedia Dysfunction = PPID) vor. Als auslösender Faktor für die Hufrehe wird aktuell eine Hyperinsulinämie, die durch eine Insulindysregulation zustande kommt, angenommen. Eine Insulindysregulation liegt beim equinen metabolischen Syndrom vor und kann auch bei an PPID erkrankten Pferden vorkommen. Es wurde bereits gezeigt, dass eine experimentell induzierte Hyperinsulinämie eine Veränderung des Plasma-Aminosäureprofils von Pferden bewirkt. Das Projekt untergliederte sich in 2 Teilprojekte. Im ersten Teilprojekt wurde die Plasma-Aminosäurekonzentration von an PPID erkrankten Pferden mit der gesunder Pferde verglichen. Es wurde daher EDTA-Plasma von Pferden von Pferden, die aus unterschiedlichen Gründen in der Pferdeklinik der Freien Universität Berlin vorgestellt wurden und Laboruntersuchungen von mit EDTA antikoaguliertem Blut erforderten, asserviert. Mit diesem Plasma wurde die basale ACTH-Konzentration sowie das Aminosäureprofil bestimmt. Pferde galten als an PPID erkrankt, wenn die ACTH-Konzentration ≥ 100 pg/ml lag, sie also zu jedem Zeitpunkt als erkrankt gelten. Pferde wurden als gesund (nPPID) definiert, wenn die ACTHKonzentration unter 30 pg/ml lag, sie also zu jedem Zeitpunkt als gesund gelten. Pferde, die Pergolid erhielten und deren ACTH Konzentration ≤ 30 pg/ml lag, wurden der Gruppe PPIDrr (PPID, ACTH im Referenzbereich) zugeordnet und Pferde, die Pergolid erhielten und deren ACTH Konzentration ACTH ≥ 100 pg/ml lag, wurden der Gruppe PPIDarr (PPID, ACTH oberhalb des Referenzbereichs) zugeordnet. Insgesamt wurden 93 Pferde untersucht, davon 88 Pferde in der Klinik und 5 Pferde in einer Privatpraxis. Davon erfüllten 53 Pferde die Einschlusskriterien (ACTH ≤ 30 pg/ml oder ACTH ≥ 100 pg/ml). 25 Pferde wurden als nPPID, 20 als PPID, 5 als PPIDrr und 3 als PPIDarr diagnostiziert. Zwischen den Gruppen lagen keine signifikanten Unterschiede hinsichtlich des Geschlechtes und der Rasse vor. Es wurden jedoch signifikante Unterschiede zwischen den Gruppen hinsichtlich der Fütterung, des Alters und der ACTH-Konzentration festgestellt. Zwischen nPPID und PPIDrr sowie PPID und PPIDrr lagen signifikante Unterschiede bezüglich der Fütterung vor: Alle als PPIDrr identifizierten Pferde wurden ausschließlich mit Heu gefüttert, während die nPPID- und PPID-Patienten neben Heu auch Kraftfutter (1 nPPID), Mash (10 nPPID, 3 PPID) oder Gras (1 nPPID, 12 PPID) erhielten. Ein Pferd (nPPID) erhielt nur Gras. Zudem waren an PPID erkrankte Pferde signifikant älter als nPPID-Pferde. Zwischen den anderen Gruppen gab es keine signifikanten Unterschiede hinsichtlich des Alters. Es gab keine signifikanten Unterschiede in der ACTHKonzentration zwischen nPPID und PPIDrr. Die ACTH-Konzentration von PPID-Patienten war signifikant höher als bei nPPID, PPIDrr und PPIDarr. Darüber hinaus hatten PPIDarr-Pferde signifikant höhere ACTH-Konzentrationen als PPIDrr-Pferde. Bei den Plasma-Aminosäurekonzentrationen lagen folgende signifikante Unterschiede vor: Arginin war signifikant höher bei PPIDrr als bei PPID und nPPID, Asparagin war signifikant höher bei PPID, PPIDrr und PPIDarr als bei nPPID, Citrullin war signifikant höher bei PPIDrr als in nPPID und PPID, Cystein war signifikant niedriger bei PPIDrr als bei PPID, nPPID und PPIDarr und Glutamin war signifikant höher bei PPID und PPIDarr als bei nPPID. Im zweiten Teil des Projektes wurde die Plasma-Aminosäurekonzentration adipöser Pferde mit und ohne chronische Hufrehe/schlanker an chronischer Hufrehe erkrankter Pferde, die für einen kombinierten Glukose-Insulin-Test (CGIT) sowie für eine röntgenologische Untersuchung der Hufe vorgestellt wurden. Insgesamt wurden 25 adipöse Pferde und zwei schlanke Pferde mit rezidivierender Hufrehe einem CGIT unterzogen. Von den 27 Pferden, die vorgestellt wurden, waren fünf nicht Insulin-dysreguliert (adipös), 14 waren Insulin-dysreguliert und acht waren Insulin-dysreguliert mit röntgenologischen Anzeichen einer chronischen Hufrehe. Es wurden signifikante Unterschiede in den Ruhekonzentrationen der Aminosäuren (Citrullin, GABA, Methionin) zwischen gesunden und Insulin-dysregulierten an Hufrehe erkrankten Pferden festgestellt. Außerdem lagen Unterschiede in der Plasma-Konzentration von GABA zwischen Insulin-dysregulierten Pferden mit und ohne Hufrehe vor. Insgesamt liefert dieses Projekt interessante Ansätze, weitere diagnostische Tests, insbesondere zur Detektion von Hufrehe-gefährdeten Pferde, zu entwickeln und möglicherweise auch zur Erforschung von Futterergänzungsmitteln

Molecular Characterization of Equine Staphylococcus aureus Isolates Exhibiting Reduced Oxacillin Susceptibility

The detection of borderline oxacillin-resistant Staphylococcus aureus (BORSA) represents a challenge to both, veterinary and human laboratories. Between 2015 and 2017, 19 equine S. aureus with elevated minimal inhibitory concentrations for oxacillin were detected in routine diagnostics. The aim of this study was to characterize these isolates to identify factors possibly associated with the BORSA phenotype. All S. aureus were subjected to antimicrobial susceptibility testing and whole genome sequencing (WGS). A quantifiable β-lactamase activity assay was performed for a representative subset of 13 isolates. The WGS data analysis of the 19 BORSA isolates identified two different genomic lineages, sequence type (ST) 1 and ST1660. The core genome multilocus sequence typing (cgMLST) revealed a close relatedness of all isolates belonging to either ST1 or ST1660. The WGS analysis identified the resistance genes aadD, dfrG, tet(L), and/or blaZ and aacA-aphD. Phenotypic resistance to penicillins, aminoglycosides, tetracyclines, fluoroquinolones and sulfamethoxazole/trimethoprim was observed in the respective isolates. For the penicillin-binding proteins 1–4, amino acid substitutions were predicted using WGS data. Since neither transglycosylase nor transpeptidase domains were affected, these alterations might not explain the BORSA phenotype. Moreover, β-lactamase activity was found to be associated with an inducible blaZ gene. Lineage-specific differences regarding the expression profiles were noted.Peer Reviewe

Seroprevalence of <i>Borrelia burgdorferi</i> sensu lato and <i>Anaplasma phagocytophilum</i> Infections in German Horses

There are limited data on Lyme borreliosis (LB), a tick-borne disease caused by the Borrelia burgdorferi sensu lato complex, in horses. Seropositivity is not necessarily associated with clinical disease. Data on seropositivity against Borrelia burgdorferi and Anaplasma phagocytophilum in German horses are sparse. Therefore, serum samples from horses (n = 123) suspected of having Lyme borreliosis and clinically healthy horses (n = 113) from the same stables were tested for specific antibodies against Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum. The samples were screened for antibodies against Borrelia burgdorferi (ELISA and an IgG line immunoblot assay). Furthermore, the samples were examined for antibodies against B. burgdorferi and Anaplasma phagocytophilum with a validated rapid in-house test (SNAP® 4Dx Plus® ELISA). The clinical signs of suspect horses included lameness (n = 36), poor performance (n = 19), and apathy (n = 12). Twenty-three percent (n = 26) of suspect horses and 17% (n = 18) of clinically healthy horses were seropositive for having a Borrelia burgdorferi sensu lato infection (p = 0.371), showing that the detection of specific antibodies against B. burgdorferi alone is not sufficient for a diagnosis of equine LB. Anaplasma phagocytophilum seropositivity and seropositivity against both pathogens was 20%/6% in suspect horses and 16%/2% in the clinically healthy population, showing only minor differences (p = 0.108). Unspecific testing for antibodies against B. burgdorferi without clinical suspicion of Lyme borreliosis is not recommended since the clinical relevance of seropositivity against Borrelia burgdorferi sensu lato remains to be elucidated

A Pilot Randomised Clinical Trial Comparing a Short-Term Perioperative Prophylaxis Regimen to a Long-Term Standard Protocol in Equine Colic Surgery

Background: For surgical interventions classified as clean or clean-contaminated, including laparotomy, guidelines in human and veterinary medicine recommend a short-term perioperative antibiotic prophylaxis (PAP). In equine colic surgery, however, PAP commonly exceeds 24 h. Objectives: The aim of this study was to compare a single-shot to a 5-day lasting PAP considering surgical site infections (SSI) and other adverse effects probably associated with the particular antimicrobial regimen. Study design: The study was designed as a randomised non-inferiority pilot study including horses subjected to colic surgery while receiving one of two distinct PAP regimens. Methods: All horses (n = 67) included in the study received the standard physical examination before and after surgery. Colic surgery was performed according to the current standard of the clinic. Horses were randomly assigned to two groups, receiving either the “single-shot” or the “5-day lasting” antibiotic prophylaxis. The “single-shot” group (n = 30) received penicillin and gentamicin only once before and, if needed, during surgery, whereas the “5-day lasting” group (n = 37) received antibiotics for five days. In addition to the standard laboratory examinations, serum amyloid A and fibrinogen were determined preoperatively and during five days after surgery. SSI, postoperative colitis and haemolytic anaemia were classified as postoperative complications potentially related to antibiotic use. Results: The outcome of this preliminary non-inferiority clinical trial showed that the occurrence of postoperative adverse events (i.e., SSI, postoperative colitis and haemolytic anaemia) lacked significant differences between the study groups. Main limitations: The main limitations of this study are the limited group sizes and our inability to blind the study. Conclusions: Single-shot PAP seems to be an alternative approach considering the 5-day lasting protocol commonly used in equine abdominal surgery. However, a proper hygiene management together with a close clinical and laboratory monitoring of the equine patient is indispensable