Antibiotic prophylaxis and hospitalization of horses subjected to median laparotomy: gut microbiota trajectories and abundance increase of Escherichia

Introduction: Horse clinics are hotspots for the accumulation and spread of clinically relevant and zoonotic multidrug-resistant bacteria, including extended-spectrum β-lactamase producing (ESBL) Enterobacterales. Although median laparotomy in cases of acute equine colic is a frequently performed surgical intervention, knowledge about the effects of peri-operative antibiotic prophylaxis (PAP) based on a combination of penicillin and gentamicin on the gut microbiota is limited. Methods: We collected fecal samples of horses from a non-hospitalized control group (CG) and from horses receiving either a pre-surgical single-shot (SSG) or a peri-operative 5-day (5DG) course of PAP. To assess differences between the two PAP regimens and the CG, all samples obtained at hospital admission (t0), on days three (t1) and 10 (t2) after surgery, were screened for ESBL-producing Enterobacterales and subjected to 16S rRNA V1–V2 gene sequencing. Results: We included 48 samples in the SSG (n = 16 horses), 45 in the 5DG (n = 15), and 20 in the CG (for t0 and t1, n = 10). Two samples of equine patients receiving antibiotic prophylaxis (6.5%) were positive for ESBL-producing Enterobacterales at t0, while this rate increased to 67% at t1 and decreased only slightly at t2 (61%). Shannon diversity index (SDI) was used to evaluate alpha-diversity changes, revealing there was no significant difference between horses suffering from acute colic (5DG, SDImean of 5.90, SSG, SDImean of 6.17) when compared to the CG (SDImean of 6.53) at t0. Alpha-diversity decreased significantly in both PAP groups at t1, while at t2 the onset of microbiome recovery was noticed. Although we did not identify a significant SDImean difference with respect to PAP duration, the community structure (beta-diversity) was considerably restricted in samples of the 5DG at t1, most likely due to the ongoing administration of antibiotics. An increased abundance of Enterobacteriaceae, especially Escherichia, was noted for both study groups at t1. Conclusion: Colic surgery and PAP drive the equine gut microbiome towards dysbiosis and reduced biodiversity that is accompanied by an increase of samples positive for ESBL-producing Enterobacterales. Further studies are needed to reveal important factors promoting the increase and residency of ESBL-producing Enterobacterales among hospitalized horses

Frequency, Local Dynamics, and Genomic Characteristics of ESBL-Producing Escherichia coli Isolated From Specimens of Hospitalized Horses

Previous research identified veterinary clinics as hotspots with respect to accumulation and spread of multidrug resistant extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (EC). Therefore, promoting the prudent use of antibiotics to decrease selective pressure in that particular clinical environment is preferable to enhance biosecurity for animal patients and hospital staff. Accordingly, this study comparatively investigated the impact of two distinct perioperative antibiotic prophylaxis (PAP) regimens (short-term versus prolonged) on ESBL-EC carriage of horses subjected to colic surgery. While all horses received a combination of penicillin/gentamicin (P/G) as PAP, they were assigned to either the “single-shot group” (SSG) or the conventional “5-day group” (5DG). Fecal samples collected on arrival (t0), on the 3rd (t1) and on the 10th day after surgery (t2) were screened for ESBL-EC. All isolates were further investigated using whole genome sequences. In total, 81 of 98 horses met the inclusion criteria for this study. ESBL-EC identified in samples available at t0, t1 and t2 were 4.8% (SSG) and 9.7% (5DG), 37% (SSG) and 47.2% (5DG) as well as 55.6% (SSG) and 56.8% (5DG), respectively. Regardless of the P/G PAP regimen, horses were 9.12 times (95% CI 2.79–29.7) more likely to carry ESBL-EC at t1 compared to t0 (p < 0.001) and 15.64 times (95% CI 4.57–53.55) more likely to carry ESBL-EC at t2 compared to t0 (p < 0.001). ESBL-EC belonging to sequence type (ST) 10, ST86, ST641, and ST410 were the most prevalent lineages, with blaCTX–M–1 (60%) being the dominant ESBL gene. A close spatio-temporal relationship between isolates sharing a particular ST was revealed by genome analysis, strongly indicating local spread. Consequently, hospitalization itself has a strong impact on ESBL-EC isolation rates in horses, possibly masking differences between distinct PAP regimens. The results of this study reveal accumulation and spread of multi-drug resistant ESBL-EC among horses subjected to colic surgery with different P/G PAP regimens, challenging the local hygiene management system and work-place safety of veterinary staff. Moreover, the predominance of particular ESBL-EC lineages in clinics providing health care for horses needs further investigation.Peer Reviewe

Antibiotic prophylaxis and hospitalization of horses subjected to median laparotomy: gut microbiota trajectories and abundance increase of Escherichia

IntroductionHorse clinics are hotspots for the accumulation and spread of clinically relevant and zoonotic multidrug-resistant bacteria, including extended-spectrum β-lactamase producing (ESBL) Enterobacterales. Although median laparotomy in cases of acute equine colic is a frequently performed surgical intervention, knowledge about the effects of peri-operative antibiotic prophylaxis (PAP) based on a combination of penicillin and gentamicin on the gut microbiota is limited.MethodsWe collected fecal samples of horses from a non-hospitalized control group (CG) and from horses receiving either a pre-surgical single-shot (SSG) or a peri-operative 5-day (5DG) course of PAP. To assess differences between the two PAP regimens and the CG, all samples obtained at hospital admission (t0), on days three (t1) and 10 (t2) after surgery, were screened for ESBL-producing Enterobacterales and subjected to 16S rRNA V1–V2 gene sequencing.ResultsWe included 48 samples in the SSG (n = 16 horses), 45 in the 5DG (n = 15), and 20 in the CG (for t0 and t1, n = 10). Two samples of equine patients receiving antibiotic prophylaxis (6.5%) were positive for ESBL-producing Enterobacterales at t0, while this rate increased to 67% at t1 and decreased only slightly at t2 (61%). Shannon diversity index (SDI) was used to evaluate alpha-diversity changes, revealing there was no significant difference between horses suffering from acute colic (5DG, SDImean of 5.90, SSG, SDImean of 6.17) when compared to the CG (SDImean of 6.53) at t0. Alpha-diversity decreased significantly in both PAP groups at t1, while at t2 the onset of microbiome recovery was noticed. Although we did not identify a significant SDImean difference with respect to PAP duration, the community structure (beta-diversity) was considerably restricted in samples of the 5DG at t1, most likely due to the ongoing administration of antibiotics. An increased abundance of Enterobacteriaceae, especially Escherichia, was noted for both study groups at t1.ConclusionColic surgery and PAP drive the equine gut microbiome towards dysbiosis and reduced biodiversity that is accompanied by an increase of samples positive for ESBL-producing Enterobacterales. Further studies are needed to reveal important factors promoting the increase and residency of ESBL-producing Enterobacterales among hospitalized horses

Perioperative antibiotic prophylaxis in horses undergoing aseptic colic surgery

Im Rahmen dieser Promotion wurde eine prospektive, randomisierte Studie zu postoperativen Komplikationen bei Pferden nach chirurgischen Eingriffen bei kolikoperierten Patienten erstellt. Ziel dieser Studie bestand darin, Unterschiede hinsichtlich postoperativer Komplikationen zwischen zwei verschiedenen Regimen von Antibiotika (Single-Shot vs. konventionelle Antibiotikagabe) zu evaluieren und eine Single-Shot Gabe als antibiotische Prophylaxe bei diesen Eingriffen zukünftig in Erwägung zu ziehen. Für die prospektive Studie konnten 67 Pferde ausgewertet werden, die in der Klinik für Pferde, FU Berlin einer Kolikoperation unterzogen wurden. Die Pferde wurden randomisiert einer der beiden Gruppen zugeordnet. Alle Pferde wurden intensiv über zehn Tage überwacht. In den Wundbeurteilungen an Tag drei, fünf und zehn wurden mittels eines Scores die Kriterien Exsudation, Schwellung und Nahtdehiszenz evaluiert. Weiterhin wurden die Blutwerte Leukozyten, Hämatokrit, Totalprotein, Serumamyloid A, Fibrinogen und Laktat prä- und postoperativ in den ersten fünf Tagen und am zehnten Tag ermittelt. 1. Hauptfrage: Ist eine Single-Shot Antibiotikagabe gleichwertig zu dem konventionellen perioperativen Antibiotikamanagement hinsichtlich möglicher, postoperativer Komplikationen? Mittels eines linearen Modells mit negativer Binomialverteilung wurden die Wundscores beurteilt. Es gab keinen signifikanten Unterschied hinsichtlich des Gesamtscores aller Tage zwischen den zu vergleichenden Gruppen (p = 0,985, lineare Regression). Sowohl bei der Entstehung von Wundinfektionen in den ersten zehn Tagen postoperativ (p = 0,2, exakter Fischer-Test) als auch bei der Entstehung von Wundinfektionen innerhalb dreißig Tagen postoperativ (p = 0,07, exakter Fischer-Test) gab es keinen signifikanten Unterschied. Auch hinsichtlich der Entstehung von postoperativer Colitis (p = 0,2, exakter Fischer-Test) als auch der Entstehung postoperativer hämolytischer Anämie (p = 0,317, exakter Fischer-Test) gab es keine signifikanten Unterschiede zwischen den Gruppen. Bei einer Studienpower von 60% und einem gesetzten Limit von 15%, entstand eine Differenz von 7,7 % zwischen den zu vergleichenden Gruppen in der Beurteilung des Auftretens von postoperativ auftretenden Komplikationen. Es existiert somit keine Unterlegenheit der Single-Shot Gruppe gegenüber der konventionellen Gruppe hinsichtlich des Auftretens von unerwünschten Komplikationen postoperativ. 1. Detailfragen: Welchen Einfluss hat das perioperative Antibiotikamanagement (SingleShot versus konventionell) auf die Entzündungsparameter im Blut des Pferdes? Welchen Einfluss hat das perioperative Management weiterhin auf die Entwicklung resistenter Erreger in der Nase und dem Kot der Pferde? Mithilfe eines linearen gemischten Regressionsmodells wurden die Blutwerte ausgewertet. Es existierte kein signifikanter Unterschied zwischen den SAA-Werten (p = 0,799, lineares Regressionsmodell), den Leukozyten (p = 0,998, lineares Regressionsmodell), den Fibrinogenwerten (p = 0,545, lineares Regressionsmodell) und den Totalproteinwerten (p = 0,722, lineares Regressionsmodell) zwischen den beiden zu vergleichenden Gruppen. Eine Auswertung der erhobenen Nasentupfer- und Kotproben wurde mit dem Chi-QuadratTest und dem exakten Fisher-Test erhoben. Auch hier fand sich kein signifikanter Unterschied von MRSA (p = 0,288, Chi-Quadrat-Test), MDR-Enterobacterales (p = 0,286, Chi-Quadrat– Test) und Acinetobacter baumannii (p = 0,493, exakter Fisher-Test) in den gewonnenen Nasentupferproben am dritten Tag postoperativ zwischen den zu vergleichenden Gruppen. Hinsichtlich der Kotproben an diesem Tag war kein signifikanter Unterschied bei dem Auftreten von MDR-Enterobacterales (p = 0,099, Chi-Quadrat-Test) und Acinetobacter baumannii (p = 0,503, Chi-Quadrat-Test) zu verzeichnen. Auch am zehnten Tag postoperativ gab es keinen signifikanten Unterschied hinsichtlich des Auftretens von MRSA (p = 0,920, Chi-QuadratTest), MDR-Enterobacterales (p = 0,481, exakter Fisher-Test) und Acinetobacter baumannii (p = 0,494, exakter Fisher-Test) in der Nase der Studienteilnehmer. Die Kotprobenergebnisse wiesen ebenfalls keine signifikanten Unterschiede zwischen den Gruppen mit MDR-Enterobacterales (p = 0,938, Chi-QuadratTest) und Acinetobacter baumannii (p = 0,240, exakter Fisher-Test) auf. Auffällig war jedoch, dass das Auftreten von multiresistenten E.coli in der Kotprobe und Acinetobacter baumannii in Nasentupfer- und Kotprobe ausschließlich in der konventionellen Gruppe nachzuweisen war. Es konnte jedoch keine Signifikanz nachgewiesen werden. Zusammenfassend ist der Einsatz eines perioperativen Managements in Form eines SingleShots bei sauberen und sauber-kontaminierten Operationen im Bereich der Kolikchirurgie zu empfehlen. Auch diese Studie verdeutlicht, dass ein vermehrter Einsatz von Antibiotika das Auftreten von resistenten Bakterien begünstigt. Um postoperative Komplikationen im Rahmen einer antimikrobiellen Single-Shot Gabe noch sicherer zu beurteilen, empfehlen sich weitere Studien mit höheren Fallzahlen.For this dissertation a randomised prospective study was carried out to assess postoperative complications when using two types of perioperative antibiotic treatments in horses undergoing emergency laparotomies. The aim of this study was to identify differences in postoperative complications between the two types of perioperative antibiotic treatments (Single-Shot versus 120 hour treatment). Sixtyseven horses who were undergoing a surgical emergency celiotomy in the clinic for horses at the FU Berlin were included in the prospective study. All patients were randomised to one of the treatment groups. All horses were monitored for ten days after surgery. A scoring system for exsudation, swelling and incisional dehiscence was established. A wound assesment on day three, five and ten after surgery was carried out. The blood parameters leucocytes, packed cell volume, total protein, serum amyloid a, fibrinogen and lactat were measured on the first to the fifth day and on day ten after surgery. 1. Main aim of the study: Is a use of single shot antibiotic treatment perioperative equivalent in regard to surgical side infections and other postoperative complications in horses to the common 120 hours antibiotic treatment? For the evaluation of the wound scores a linear regressionmodel with negative binomial distributation was used. There were no significant differences in the total scores between both antibiotic groups (p = 0.985, linear regression). In the development of surgical side infections in the first ten days after surgery (p = 0.2, exact fisher-test) as well as the development within thirty days postoperative (p = 0.07, fisher-exact test) there was no significant difference. Regarding the appearance of postsurgical colitis in horses (p = 0.2, exact fisher-test) and the development of postoperative hemolytic anemia (p = 0.317, exact fisher-test) there were no significant differences between both groups. With a study power of 60% and a staid limit of 15% there was a difference of 7,7% between the comparative groups in the evaluation of the occurence of postoperative complications. There was no inferiority of the single shot group adverse the conventional group with the regard to the occurence of postoperative complications. 1. Detail questions: How does the postoperative antimicrobial treatment (single shot versus conventional) influence the inflammation parameters in the blood of the horses? Is there an influence of the antibiotic treatment on the appearance of resistant bacteria in the nose and feces of the horses? With the use of a linear mixed regression modell the blood parameters of the horses were evaluated. There were no significant differences between the serum amyloid a parameters (p = 0.799, linear regressionmodel), the leucocytes (p = 0.988, linear regressionmodel), the fibrinogen parameters (p = 0.545, linear regressionmodel), and the total protein parameters (p = 0.722, linear regressionmodel), between both groups. To evaluate the samples from the noses and faeces the chi square test and the fisher exact test was utilized. There were no significant differences in the colonization with MRSA (p = 0.288, chi square test), MDR-Enterobacterales (p = 0.286, chi square test) and Acinetobacter baumannii (p = 0.493, fisher exact test) in the nose samples between the groups on the third day after surgery. The faecal samples on this day showed no significant differences in the colonization of MDR-Enterobacterales (p = 0.099, chi square test) and Acinetobacter baumannii (p = 0.503, chi square test). On the tenth day after surgery there were no significant difference on the establishment of MRSA (p = 0.920, chi square test), MDR-Enterobacterales (p = 0.481, fisher exact test) and Acinetobacter baumannii (p = 0.494, fisher exact test) in the nose samples between the groups. No significant differences were found in the establishment of MDR-Enterobacterales (p = 0.938, chi square test) and Acinetobacter baumannii (p = 0.240, fisher exact test) in the faecal samples on this day. It was noticable that the colonization with multidrug resistant E.coli and Acinetobacter baumannii in the nose and the faecal samples was only found in the conventional group. The resulat was not significant. In summary the use of a single shot as a perioperative prophylaxis in horses undergoing an emergency laparotomy in clean and clean-contamined surgerys is advisable. This prospective study shows that an increased use of antibiotic prophylaxis and therapy promote the occurence of resistant bacteria. To evaluate postoperative complications after a single shot use more safely additional studys with a higher study population would be recommendable

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

The gut microbiome of horses: current research on equine enteral microbiota and future perspectives

Understanding the complex interactions of microbial communities including bacteria, archaea, parasites, viruses and fungi of the gastrointestinal tract (GIT) associated with states of either health or disease is still an expanding research field in both, human and veterinary medicine. GIT disorders and their consequences are among the most important diseases of domesticated Equidae, but current gaps of knowledge hinder adequate progress with respect to disease prevention and microbiome-based interventions. Current literature on enteral microbiomes mirrors a vast data and knowledge imbalance, with only few studies tackling archaea, viruses and eukaryotes compared with those addressing the bacterial components. Until recently, culture-dependent methods were used for the identification and description of compositional changes of enteral microorganisms, limiting the outcome to cultivatable bacteria only. Today, next generation sequencing technologies provide access to the entirety of genes (microbiome) associated with the microorganisms of the equine GIT including the mass of uncultured microbiota, or “microbial dark matter”. This review illustrates methods commonly used for enteral microbiome analysis in horses and summarizes key findings reached for bacteria, viruses and fungi so far. Moreover, reasonable possibilities to combine different explorative techniques are described. As a future perspective, knowledge expansion concerning beneficial compositions of microorganisms within the equine GIT creates novel possibilities for early disorder diagnostics as well as innovative therapeutic approaches. In addition, analysis of shotgun metagenomic data enables tracking of certain microorganisms beyond species barriers: transmission events of bacteria including pathogens and opportunists harboring antibiotic resistance factors between different horses but also between humans and horses will reach new levels of depth concerning strain-level distinctions.Peer Reviewe