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Citation: Rockow, M.; Griffenhagen,
G.; Landolt, G.; Hendrickson, D.;
Pezzanite, L. Current Antimicrobial
Use in Horses Undergoing
Exploratory Celiotomy: A Survey of
Board-Certified Equine Specialists.
Animals 2023,13, 1433. https://
doi.org/10.3390/ani13091433
Academic Editor: Claudia Giannetto
Received: 7 April 2023
Revised: 15 April 2023
Accepted: 20 April 2023
Published: 22 April 2023
Copyright: © 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
animals
Article
Current Antimicrobial Use in Horses Undergoing Exploratory
Celiotomy: A Survey of Board-Certified Equine Specialists
Meagan Rockow, Gregg Griffenhagen , Gabriele Landolt, Dean Hendrickson and Lynn Pezzanite *
Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences,
Colorado State University, Fort Collins, CO 80523, USA; meagan.rockow@rams.colostate.edu (M.R.);
gregg.griffenhagen@colostate.edu (G.G.); gabriele.landolt@colostate.edu (G.L.);
dean.hendrickson@colostate.edu (D.H.)
*Correspondence: lynn.pezzanite@colostate.edu
Simple Summary:
Recommendations for antimicrobial prophylaxis are well described for abdominal
surgery in human medicine, but the information is limited for equine veterinary practice. In addition,
recent studies support a reduced duration of antimicrobials postoperatively in horses undergoing
celiotomy compared to what has been previously reported; however, protocols vary widely between
practices. The overall objective of this study was to provide an updated characterization of the
‘current state of play’ of antimicrobial use in horses undergoing emergency colic surgery and the
perceived risk of postoperative complications. Specifically, the aim was to poll veterinary internists
and surgeons to determine current usage among respondents in the United States. Improved
knowledge of recommendations for antimicrobial prophylaxis for commonly performed procedures
in equine practice, such as abdominal surgery, may help to reduce postoperative complications and
enhance antimicrobial stewardship at a time when resistance is increasing in equine practice.
Abstract:
In the past decade, there has been a considerable increase in the recognition of antimicrobial
resistance in equine practice. The objective of this study was to survey the current clinical use of
antimicrobials for a commonly performed surgical procedure (exploratory celiotomy) with the goal of
understanding how recent literature and changes in microbial resistance patterns may have impacted
antimicrobial selection practices. An electronic survey was distributed to veterinary professionals
within the American College of Veterinary Internal Medicine (ACVIM) and the American College of
Veterinary Surgery (ACVS). A total of 113 completed surveys were returned. Practitioners reported
antimicrobials were most frequently given 30–60 min preoperatively (63.1%). Two antimicrobial
classes were typically administered (95.5%), with gentamicin (98.2%) and potassium penicillin (74.3%)
being the most common. Antimicrobials were typically not re-dosed intraoperatively (78.6%). Factors
that affected overall treatment length postoperatively included resection (81.4%), bloodwork (75.2%),
enterotomy (74.3%), fever (85.0%), incisional complications (76.1%), and thrombophlebitis (67.3%).
The most common duration of antimicrobial use was 1–3 d for non-strangulating lesions (54.4% of
cases) and inflammatory conditions such as enteritis or peritonitis (50.4%), and 3–5 d for strangulating
lesions (63.7%). Peri-incisional and intra-abdominal antimicrobials were used by 24.8% and 11.5% of
respondents, respectively. In summary, antimicrobial usage patterns were highly variable among
practitioners and, at times, not concordant with current literature.
Keywords: horse; antimicrobials; colic; celiotomy; survey
1. Introduction
Antimicrobial administration in human and veterinary medicine has led to important
advancements in patient care. However, inappropriate antimicrobial usage has been
shown to contribute to bacterial drug resistance and is not without risk of complications.
Guidelines for use aim to maximize therapeutic efficacy while reducing the negative
Animals 2023,13, 1433. https://doi.org/10.3390/ani13091433 https://www.mdpi.com/journal/animals
Animals 2023,13, 1433 2 of 16
impacts on public health. Perioperative prophylaxis is the most common reason for use
of antimicrobials [
1
–
3
] and has been shown to decrease surgical site infection incidence,
postoperative complications, and the cost of treatment [
4
–
6
]. However, reported compliance
with prophylaxis guidelines in veterinary and human practice varies [
7
,
8
]. For example,
one study indicated that only 6.3% of horses undergoing surgery received preoperative
antimicrobials within 60 min of the initial incision [8].
Exploratory celiotomy (‘colic’) surgery in horses is generally considered a ‘clean con-
taminated’ procedure, although a minority of cases may be considered either ‘clean’ if per-
formed electively and without enterotomy/resection or ‘dirty’ following intra-abdominal
contamination or intestinal perforation [
9
–
11
]. Current recommendations for antimicrobial
use in ‘clean-contaminated’ procedures include: (1) perioperative antimicrobial prophylaxis
is indicated; (2) broad-spectrum selection is recommended but should consist of lower-
generation drugs to minimize the emergence of resistant bacterial strains; (3) selection
should be based on commonly identified isolates; (4) the intravenous route of adminis-
tration within 30 to 60 min prior to incision is recommended; (5) antimicrobials should
be re-dosed intraoperatively if surgery continues beyond two half-lives; and (6) aseptic
technique should be followed. Complications after colic surgery that may be reduced
with appropriate antimicrobial protocols reportedly include surgical site infection, throm-
bophlebitis, pneumonia, peritonitis, colitis, and Salmonella shedding [9,12–14].
The most recent available review of antimicrobial prophylaxis for exploratory ce-
liotomy in horses at one large university referral practice was reported in 2012 [
9
] and
concluded that the majority of horses treated for surgical colic at that facility received
inaccurate antimicrobial prophylaxis, both in terms of the dose received and the timing of
drug administration [
9
]. More recent studies have demonstrated no added beneficial effect
of 120 h vs. 72 h or a single preoperative dose of antimicrobials to reduce the incidence of
surgical site infection [
11
,
15
]. Many institutions base antimicrobial usage guidelines on
recommendations from human practice, the impression of common practice within veteri-
nary medicine, or consensus statements when available, as clinical trials in equine practice
comparing antimicrobial protocols for gastrointestinal surgery are limited [8,16–19].
Therefore, the overall aim of this study was to provide an updated examination of an-
timicrobial usage for abdominal surgery in horses. Specifically, the aim was to poll members
of the American College of Veterinary Internal Medicine (ACVIM) and American College
of Veterinary Surgeons (ACVS) to determine current antimicrobial usage in the United
States as well as their perceived frequency of postoperative complications. We hypothe-
sized that despite published recommendations for clean-contaminated procedures such as
exploratory celiotomy in horses, antimicrobial practices would vary between clinicians.
2. Materials and Methods
2.1. Prospective Polling of ACVIM and ACVS Diplomates on Current Antimicrobial Practices
A survey was posted on the ACVIM listserve, and the ACVS college was polled via
email to survey specialists on their current antimicrobial administration practices prior
to and following exploratory celiotomy in horses. Information requested included pre-
operative drug/dose information, number of antimicrobial classes administered, time
from preoperative dose to surgical incision (recorded or intended), whether antimicro-
bials are routinely re-dosed during surgery, and if so at what time point following the
first dose, duration of use, and whether postoperative use is dictated by factors specific
to an individual case such as procedure performed (e.g., enterotomy, bowel resection)
or bloodwork (e.g., complete blood count indicating normal leukocyte and neutrophil
counts), whether peri-incisional or intra-abdominal antimicrobials were administered, and
incidence of postoperative complications (e.g., fever (>101.5
◦
F), incisional complications,
thrombophlebitis, or other catheter associated complications and Salmonella shedding) is
known for that practice.
Animals 2023,13, 1433 3 of 16
2.2. Data Analysis
The respondents were able to submit an incomplete survey if they so desired. When
appropriate, the respondents could provide more than one response to a specific question.
Pearson’s chi-squared test and Fisher’s exact test were performed to investigate the associa-
tion between predictors (years in practice, ACVIM vs. ACVS college) and other reported
binary outcomes (intraoperative redosing, peri-incisional, or intra-abdominal antibiotics).
Prism software v8.4.1 (GraphPad Software Inc., La Jolla, CA, USA) and R version 4.1.2 (R
Foundation for Statistical Computing, Vienna, Austria) were used for graph generation
and statistical analyses, with significance assessed as p< 0.05.
3. Results
3.1. Demographic Information
A total of 113 completed surveys were returned (68.8% ACVS/ECVS [n = 1 ECVS
with the remainder being ACVS] and 31.2% ACVIM/ECVIM [n = 1 ECVIM with the
remainder being ACVIM]). As the surveys were distributed both to a listserve and an email
distribution list, the total number of surveys sent and therefore the total response rate were
unable to be determined. The number of years in practice were relatively evenly distributed
between experience group levels, with 38.6% of respondents having >20 years experience,
18.4% having 15–20 years, 20.2% having 10–15 years, 18.4% with 5–10 years, and 4.4% with
0–5 years (Figure 1). However, although the group with the fewest years of practice was
subjectively underrepresented, no associations were detected between diplomate college or
years of practice and the variables examined (Table 1).
Table 1.
Comparison of survey responses separated by diplomate college (ACVIM vs. ACVS) and
years in practice for the respondent’s answers to the questions of whether they re-dosed antibi-
otics intraoperatively, administered antibiotics peri-incisionally, or administered antibiotics intra-
abdominally. Outcomes are presented as an absolute number of responses as well as percentages
of respondents answering yes or no within each grouping. No significant differences were noted
between groups using a p-value cutoff of 0.05, and chi-squared p-values are presented (Fisher’s exact
test p-values were also agreed upon but are not shown here).
Antibiotics Redosed
Intraoperatively
Peri-Incisional Antibiotics
Administered
Intra-Abdominal Antibiotics
Administered
No Yes No Yes No Yes
Diplomate
College
ACVIM 24 (69%) 11 (31%) 29 (83%) 6 (17%) 31 (89%) 4 (11%)
ACVS 62 (84%) 12 (16%) 53 (72%) 21 (28%) 66 (89%) 8 (11%)
Chi-squared
p-value 0.079 0.236 1
Years in
Practice
0–5 4 (80%) 1 (20%) 4 (80%) 1 (20%) 5 (100%) 0
5–10 14 (70%) 6 (30%) 18 (90%) 2 (10%) 18 (90%) 2 (10%)
10–15 18 (82%) 4 (18%) 15 (68%) 7 (32%) 20 (91%) 2 (9%)
15–20 15 (71%) 6 (29%) 15 (71%) 6 (29%) 19 (90%) 2 (10%)
>20 35 (85%) 6 (15%) 30 (73%) 11 (27%) 36 (86%) 6 (14%)
Chi-squared
p-value 0.574 0.525 0.888
Animals 2023,13, 1433 4 of 16
Animals 2023, 13, x FOR PEER REVIEW 3 of 16
thrombophlebitis, or other catheter associated complications and Salmonella shedding) is
known for that practice.
2.2. Data Analysis
The respondents were able to submit an incomplete survey if they so desired. When
appropriate, the respondents could provide more than one response to a specific question.
Pearson’s chi-squared test and Fisher’s exact test were performed to investigate the asso-
ciation between predictors (years in practice, ACVIM vs. ACVS college) and other re-
ported binary outcomes (intraoperative redosing, peri-incisional, or intra-abdominal an-
tibiotics). Prism software v8.4.1 (GraphPad Software Inc., La Jolla, CA, USA) and R version
4.1.2 (R Foundation for Statistical Computing, Vienna, Austria) were used for graph gen-
eration and statistical analyses, with significance assessed as p < 0.05.
3. Results
3.1. Demographic Information
A total of 113 completed surveys were returned (68.8% ACVS/ECVS [n = 1 ECVS with
the remainder being ACVS] and 31.2% ACVIM/ECVIM [n = 1 ECVIM with the remainder
being ACVIM]). As the surveys were distributed both to a listserve and an email distribu-
tion list, the total number of surveys sent and therefore the total response rate were unable
to be determined. The number of years in practice were relatively evenly distributed be-
tween experience group levels, with 38.6% of respondents having >20 years experience,
18.4% having 15–20 years, 20.2% having 10–15 years, 18.4% with 5–10 years, and 4.4% with
0–5 years (Figure 1). However, although the group with the fewest years of practice was
subjectively underrepresented, no associations were detected between diplomate college
or years of practice and the variables examined (Table 1).
Figure 1. Demographic information of respondents, including (A) diplomate college and (B) years
in practice. Total number of responses per question indicated beneath each chart.
Table 1. Comparison of survey responses separated by diplomate college (ACVIM vs. ACVS) and
years in practice for the respondent’s answers to the questions of whether they re-dosed antibiotics
intraoperatively, administered antibiotics peri-incisionally, or administered antibiotics intra-ab-
dominally. Outcomes are presented as an absolute number of responses as well as percentages of
respondents answering yes or no within each grouping. No significant differences were noted be-
tween groups using a p-value cutoff of 0.05, and chi-squared p-values are presented (Fisher’s exact
test p-values were also agreed upon but are not shown here).
Antibiotics Redosed
Intraoperatively
Peri-incisional Antibiotics
Administered
Intra-abdominal Antibiotics
Administered
No Yes No Yes No Yes
Diplomate College
ACVIM 24 (69%) 11 (31%) 29 (83%) 6 (17%) 31 (89%) 4 (11%)
ACVS 62 (84%) 12 (16%) 53 (72%) 21 (28%) 66 (89%) 8 (11%)
Chi-squared p-
value 0.079 0.236 1
Total = 112
ACVS/ECVS (68.8%, 77/112)
ACVIM/ECVIM (31.2%, 35/112)
Diplomate College
Total = 113
0-5 years (4.4%, 5/113)
5-10 years (18.6%, 21/113)
10-15 years (20.4%, 23/113)
15-20 years (18.6%, 21/113)
>20 years (38.9%, 44/113)
Years in Practice
AB
Figure 1.
Demographic information of respondents, including (
A
) diplomate college and (
B
) years in
practice. Total number of responses per question indicated beneath each chart.
3.2. Antimicrobial Selection and Timing
The practitioners reported that preoperative antimicrobials were most commonly
administered 30 to 60 min prior to first incision (63.1%), with <30 min in 28.8% of cases
and >60 min in 2.7%, and were not recorded or varied between cases for 5.4% of respon-
dents. Two classes of antimicrobials were given in most cases (95.5%), with gentamicin
(
6.6–8.8 mg/kg
) and potassium penicillin (22,000–44,000 IU/kg) being administered most
frequently (98.2% and 74.3%, respectively). Other commonly reported antimicrobials ad-
ministered included procaine penicillin G (25,000 IU/kg) (31.9%), ceftiofur (2.2–5.0 mg/kg)
(19.5%), and cefazolin (11.0–22.0 mg/kg) (8.0%) (Figure 2).
Animals 2023, 13, x FOR PEER REVIEW 4 of 16
Years in Practice
0 - 5 4 (80%) 1 (20%) 4 (80%) 1 (20%) 5 (100%) 0
5 - 10 14 (70%) 6 (30%) 18 (90%) 2 (10%) 18 (90%) 2 (10%)
10 - 15 18 (82%) 4 (18%) 15 (68%) 7 (32%) 20 (91%) 2 (9%)
15 - 20 15 (71%) 6 (29%) 15 (71%) 6 (29%) 19 (90%) 2 (10%)
> 20 35 (85%) 6 (15%) 30 (73%) 11 (27%) 36 (86%) 6 (14%)
Chi-squared p-
value 0.574 0.525 0.888
3.2. Antimicrobial Selection and Timing
The practitioners reported that preoperative antimicrobials were most commonly ad-
ministered 30 to 60 min prior to first incision (63.1%), with <30 min in 28.8% of cases and
>60 min in 2.7%, and were not recorded or varied between cases for 5.4% of respondents.
Two classes of antimicrobials were given in most cases (95.5%), with gentamicin (6.6–8.8
mg/kg) and potassium penicillin (22,000–44,000 IU/kg) being administered most fre-
quently (98.2% and 74.3%, respectively). Other commonly reported antimicrobials admin-
istered included procaine penicillin G (25,000 IU/kg) (31.9%), ceftiofur (2.2–5.0 mg/kg)
(19.5%), and cefazolin (11.0–22.0 mg/kg) (8.0%) (Figure 2).
Figure 2. Antimicrobial selection and timing of dosing preoperatively, including (A) number of an-
timicrobial classes used, (B) timing of antimicrobial dosing preoperatively, and (C) antimicrobial
selection. Total number of responses per question indicated beneath each chart. Respondents were
not limited in the number of responses to antimicrobial selection.
3.3. Antimicrobial Dosing
Antimicrobial doses were based on preoperative weight, determined by the scale in
all horses in 26.5% of cases or, in some cases, pending patient comfort level in 53.1% of
cases. In some situations, the weights were determined by weight tape (9.7%) or a visual
estimate (10.6%). Antimicrobials were most commonly not re-dosed intraoperatively
(78.6% of cases). In those instances where antimicrobials were re-dosed, the timing of the
Tot al = 11 2
one (4.4%, 5/112)
two (95.5%, 107/112)
Number Antimicrobial Classes Used
Tota l = 111
30min (28.8%, 32/111)
30-60min (63.1%, 70/111)
>60min (2.7%, 3/111)
Not recorded/variable
(5.4%, 6/111)
Timing Antimicrobial Dosing Preoperatively
Tot al = 24 1
Gentamicin (6.6-8.8 mg/kg) (98.2%, 111/113)
Potassium penicillin (22,000-44,000 IU/kg) (74.3%, 84/113)
Ceftiofur (2.2-5.0 mg/kg) (19.5%, 22/113)
Cefazolin (11.0-22.0 mg/kg) (8.0%, 9/113)
Enrofloxacin (5.0-10.0 mg/kg) (4.4%, 5/113)
Ampicillin (15.0-20.0 mg/kg) (2.7%, 3/113)
Amoxicillin (15-30 mg/kg) (2.7%, 3/113)
Metronidazole (15.0-25.0 mg/kg) (2.7%, 3/113)
Procaine penicillin G (25,000 IU/kg) (31.9%, 36/113)
Amikacin (15.0-25.0 mg/kg) (0.9%, 1/113)
Oxytetracycline (6.6 mg/kg) (0.9%, 1/113)
Sodium penicillin G (22,000 IU/kg) (0.9%, 1/113)
Antimicrobial Selection
AB
C
Figure 2.
Antimicrobial selection and timing of dosing preoperatively, including (
A
) number of
antimicrobial classes used, (
B
) timing of antimicrobial dosing preoperatively, and (
C
) antimicrobial
selection. Total number of responses per question indicated beneath each chart. Respondents were
not limited in the number of responses to antimicrobial selection.
Animals 2023,13, 1433 5 of 16
3.3. Antimicrobial Dosing
Antimicrobial doses were based on preoperative weight, determined by the scale in
all horses in 26.5% of cases or, in some cases, pending patient comfort level in 53.1% of
cases. In some situations, the weights were determined by weight tape (9.7%) or a visual
estimate (10.6%). Antimicrobials were most commonly not re-dosed intraoperatively (78.6%
of cases). In those instances where antimicrobials were re-dosed, the timing of the second
dose was determined by 2 times x the half-life of the antimicrobial (50%), based on the
normal drug dosing interval (33.3%), or based on a different drug dosing interval (16.7%)
(Figure 3).
Animals 2023, 13, x FOR PEER REVIEW 5 of 16
second dose was determined by 2 times x the half-life of the antimicrobial (50%), based on
the normal drug dosing interval (33.3%), or based on a different drug dosing interval
(16.7%) (Figure 3).
Figure 3. Antimicrobial dosing details include (A) how doses are determined preoperatively, (B)
whether intraoperative redosing is performed, and (C) the timing of intraoperative redosing if per-
formed. Total number of responses per question indicated beneath each chart.
3.4. Treatment Length of Antimicrobial Administration
The preoperative or intraoperative factors that affected the duration of antimicrobial
administration were reported to include bowel resection (81.4%), bloodwork findings
(75.2%), and enterotomy (74.3%). Postoperative factors that affected the duration of anti-
microbial administration included fever (85.0%), incisional complications (76.1%), cathe-
ter-associated complications, including thrombophlebitis (67.3%), bloodwork findings
(46.0%), colitis (etiology other than Salmonella, 32.7%), and Salmonella shedding (15.0%).
The respondents also self-reported that clinical impression (2.7%), documented evidence
of pneumonia (6.2%), or peritonitis (8.0%), in addition to fever, were aspects of case man-
agement that may affect the duration of antimicrobial administration. The most frequently
reported average duration of antimicrobial administration was estimated to be 1 to 3 days
for non-strangulating lesions (54.5% of respondents), 3 to 5 days for strangulating lesions
(63.7%), and 1 to 3 days for inflammatory disease (50.4%) (Figure 4).
Total = 113
Weights are obtained by scale on all horses (26.5%, 30/113)
Weights are obtained by scale pending comfort level (53.1%, 60/113)
Weights are determined by weight tape (9.7%, 11/113)
Weights are determined by visual assessment (10.6%, 12/113)
Antimicrobial Dosing
Total = 112
Yes (21.4%, 24/112)
No (78.6%, 88/112)
Intraoperative Redosing Antimicrobials
Tot al = 90
2x half-life of antibiotic (16.7%, 15/90)
Normal dosing interval (11.1%, 10/90)
Different dosing interval (5.6%, 5/90)
Not redosed intraop (66.7%, 60/90)
Timing Intraoperative Redosing Antimcrobials
A
CB
Figure 3.
Antimicrobial dosing details include (
A
) how doses are determined preoperatively,
(
B
) whether intraoperative redosing is performed, and (
C
) the timing of intraoperative redosing if
performed. Total number of responses per question indicated beneath each chart.
3.4. Treatment Length of Antimicrobial Administration
The preoperative or intraoperative factors that affected the duration of antimicro-
bial administration were reported to include bowel resection (81.4%), bloodwork find-
ings (75.2%), and enterotomy (74.3%). Postoperative factors that affected the duration
of antimicrobial administration included fever (85.0%), incisional complications (76.1%),
catheter-associated complications, including thrombophlebitis (67.3%), bloodwork findings
(46.0%), colitis (etiology other than Salmonella, 32.7%), and Salmonella shedding (15.0%).
The respondents also self-reported that clinical impression (2.7%), documented evidence
of pneumonia (6.2%), or peritonitis (8.0%), in addition to fever, were aspects of case man-
agement that may affect the duration of antimicrobial administration. The most frequently
reported average duration of antimicrobial administration was estimated to be 1 to 3 days
for non-strangulating lesions (54.5% of respondents), 3 to 5 days for strangulating lesions
(63.7%), and 1 to 3 days for inflammatory disease (50.4%) (Figure 4).
3.5. Complications
Self-reported estimated incidence of complications over all surgeries evaluated in-
cluded fever, incisional infection, incisional herniation/failure, thrombophlebitis, Salmonella
shedding, and colitis (etiology other than Salmonella) (Figure 5).
Animals 2023,13, 1433 6 of 16
Animals 2023, 13, x FOR PEER REVIEW 6 of 16
Figure 4. Factors affecting the duration of antimicrobial use, including (A) preoperative or intraoper-
ative factors, (B) postoperative factors, and type of primary lesion determined intraoperatively, in-
cluding (C) non-strangulating lesions, (D) strangulating lesions, and (E) inflammatory disease. Total
number of responses per question indicated beneath each chart. For (A, B), percentages are indicated
out of the total number of individuals responding (n = 113) rather than total responses.
3.5. Complications
Self-reported estimated incidence of complications over all surgeries evaluated in-
cluded fever, incisional infection, incisional herniation/failure, thrombophlebitis, Salmo-
nella shedding, and colitis (etiology other than Salmonella) (Figure 5).
Tota l = 2 70
Enterotomy (74.3%, 84/113)
Bowel resection (81.4%, 92/113)
Bloodwork findings (75.2%, 85/113)
None - same duration in all cases (8.0%, 9/113)
Preop- or Intraoperative Factors Affecting Duration Antimicrobial Use
Tot al = 112
1 day (21.4%, 24/112)
1-3 days (54.5%, 61/112)
3-5 days (23.3%, 26/112)
>5 days (0.9%, 1/112)
Duration Antimicrobials Non-Strangulating Lesion
Tot al = 1 13
1-3 days (15.9%, 18/113)
3-5 days (63.7%, 72/113)
>5 days (20.4%, 23/113)
Duration Antimicrobials Strangulating Lesio n
Tot al = 11 3
1 day (7.1%, 8/113)
1-3 days (50.4%, 57/113)
3-5 days (31.9%, 36/113)
>5 days (10.6%, 12/113)
Duration Antimicrobials Inflammatory Disease
Total = 383
Fever (85.0%, 96/113)
Incisional (76.1%, 86/113)
Catheter-associated (67.3%, 76/113)
Salmonella shedding (15.0%, 17/113)
Colitis (non-Salmonella) (32.7%, 37/1 13)
Bloodwork (46.0%, 52/113)
Pneumonia (6.2%, 7/113)
Peritonitis (8.0 %, 9/113)
Clinical Impression (2.7%, 3/113)
Postoperative Factors Affecting Antimicrobial Duration
AB
CDE
Figure 4.
Factors affecting the duration of antimicrobial use, including (
A
) preoperative or intraop-
erative factors, (
B
) postoperative factors, and type of primary lesion determined intraoperatively,
including (
C
) non-strangulating lesions, (
D
) strangulating lesions, and (
E
) inflammatory disease.
Total number of responses per question indicated beneath each chart. For (
A
,
B
), percentages are
indicated out of the total number of individuals responding (n = 113) rather than total responses.
Animals 2023, 13, x FOR PEER REVIEW 7 of 16
Figure 5. Reported rate of complications postoperatively, including (A) fever, (B) incisional infec-
tion, (C) incisional herniation or failure, (D) thrombophlebitis, (E) Salmonella shedding, and (F) co-
litis (other than Salmonella). Total number of responses per question is indicated beneath each chart.
3.6. Peri-Incisional Antimicrobial Administration
Peri-incisional antimicrobials were reportedly used by 24.8% of respondents. Of
those who used antimicrobials by this route in their practice, antimicrobials were most
frequently implemented greater than 40% of the time (68.8% of respondents). Selection of
antimicrobials for the peri-incisional route was highly variable, with amikacin (32.1%),
gentamicin (14.3%), and penicillin (14.3%) being most commonly reported (Figure 6).
Total = 113
<10% (26.5%, 30/113)
10-20% (48.7%, 55/113)
20-40% (20.4%, 23/113)
>40% (4.43%, 20/113)
Fever (>101.5º F)
Total = 113
<10% (92.9%, 105/113)
10-20% (7.1%, 8/113)
Incisional Herniation or Failure
Total = 113
<10% (85.0%, 96/113)
10-20% (12.4%, 14/113)
20-40% (1.8%, 2/113)
>40% (0.9%, 1/113)
Salmonella shedding
Tot al = 11 3
<10% (47.8%, 54/113)
10-20% 36.3%, 41/113)
20-40% (11.5%, 13/113)
>40% (4.4%, 5/113)
Incisional Infection
Tot al = 11 3
<10% (76.1%, 86/113)
10-20% (21.2%, 24/113)
20-40% (2.7%, 3/113)
Thrombophlebitis
Tot al = 10 9
<10% (77.1%, 84/109)
10-20% (19.3%, 21/109)
20-40% (3.7%, 4/109)
Colitis (etiology non Salmonella)
AB
CD
EF
Figure 5.
Reported rate of complications postoperatively, including (
A
) fever, (
B
) incisional infection,
(
C
) incisional herniation or failure, (
D
) thrombophlebitis, (
E
)Salmonella shedding, and (
F
) colitis
(other than Salmonella). Total number of responses per question is indicated beneath each chart.
Animals 2023,13, 1433 7 of 16
3.6. Peri-Incisional Antimicrobial Administration
Peri-incisional antimicrobials were reportedly used by 24.8% of respondents. Of
those who used antimicrobials by this route in their practice, antimicrobials were most
frequently implemented greater than 40% of the time (68.8% of respondents). Selection
of antimicrobials for the peri-incisional route was highly variable, with amikacin (32.1%),
gentamicin (14.3%), and penicillin (14.3%) being most commonly reported (Figure 6).
Animals 2023, 13, x FOR PEER REVIEW 8 of 16
Figure 6. Peri-incisional antimicrobial use, including (A) reported usage (yes/no), (B) frequency of
use if reported, and (C) antimicrobial selection if used. Total number of responses per question is
indicated beneath each chart. Respondents were not limited in the number of responses to antimi-
crobial selection.
3.7. Intra-Abdominal Antimicrobial Administration
Intra-abdominal antimicrobials were reportedly used by 11.5% of respondents. Of
those who used antimicrobials by this route, the frequency of use was variable, with 35.3%
using antimicrobials in <10% of cases, 10–20% (11.8%), 20–40% (17.6%), and >40% of cases
(35.3%). The most commonly used drugs included penicillin (58.3%) and gentamicin
(16.7%) (Figure 7).
Total = 113
Yes (24.8%, 28/113)
No (75.2%, 85/113)
Peri-incisional
Antimicrobial Use
Total = 32
<10% (21.9%, 7/32)
10-20% (6.3%, 2/32)
20-40% (3.1%, 1/32)
>40% (68.8%, 22/32)
Frequency Peri-incisional
Antimicrobial Use
Total = 28
Amikacin (32.1%, 9/28)
Amoxicillin (3.6%, 1/28)
Ampicillin (3.6%, 1/28)
Cefazolin (7.1%, 2/28)
Ceftiofur (3.6%, 1/28)
Ceftriazone (3.6%, 1/28)
Cephapirin (3.6%, 1/28)
Enrofloxacin (3.6%, 1/28)
Gentamicin (14.3%, 4/28)
Neomycin (7.1%, 2/28)
Penicillin (unspecified) (10.7%, 3/28)
Potassium penicillin (3.6%, 1/28)
Sodium penicillin (3.6%, 1/28)
Selection Peri-incisional
Antimicrobial Use
AB
C
Tot al = 113
Yes (11.5%, 13/113)
No (88.5%, 100/113)
Intra-abdominal Antimicrobial Use
Total = 12
Gentamicin (16.7%, 2/12)
Potassium penicillin (41.7%, 5/12)
Sodium penicillin (8.3%, 1/12)
Penicillin (unspecified) (8.3%, 1/12)
Neomycin (8.3%, 1/12)
Ampicillin (8.3%, 1/12)
Cefazolin (8.3%, 1/12)
Selection Intra-abdominal Antimicrobial Use
Tot al = 17
<10% (35.3%, 6/17)
10-20% (11.8%, 2/17)
20-40% (17.6%, 3/17)
>40% (35.3%, 6/17)
Frequency Intra-abdominal Antimicrobial Use
AB
C
Figure 6.
Peri-incisional antimicrobial use, including (
A
) reported usage (yes/no), (
B
) frequency
of use if reported, and (
C
) antimicrobial selection if used. Total number of responses per question
is indicated beneath each chart. Respondents were not limited in the number of responses to
antimicrobial selection.
3.7. Intra-Abdominal Antimicrobial Administration
Intra-abdominal antimicrobials were reportedly used by 11.5% of respondents. Of
those who used antimicrobials by this route, the frequency of use was variable, with 35.3%
using antimicrobials in <10% of cases, 10–20% (11.8%), 20–40% (17.6%), and >40% of cases
(35.3%). The most commonly used drugs included penicillin (58.3%) and gentamicin (16.7%)
(Figure 7).
Animals 2023,13, 1433 8 of 16
Animals 2023, 13, x FOR PEER REVIEW 8 of 16
Figure 6. Peri-incisional antimicrobial use, including (A) reported usage (yes/no), (B) frequency of
use if reported, and (C) antimicrobial selection if used. Total number of responses per question is
indicated beneath each chart. Respondents were not limited in the number of responses to antimi-
crobial selection.
3.7. Intra-Abdominal Antimicrobial Administration
Intra-abdominal antimicrobials were reportedly used by 11.5% of respondents. Of
those who used antimicrobials by this route, the frequency of use was variable, with 35.3%
using antimicrobials in <10% of cases, 10–20% (11.8%), 20–40% (17.6%), and >40% of cases
(35.3%). The most commonly used drugs included penicillin (58.3%) and gentamicin
(16.7%) (Figure 7).
Total = 113
Yes (24.8%, 28/113)
No (75.2%, 85/113)
Peri-incisional
Antimicrobial Use
Total = 32
<10% (21.9%, 7/32)
10-20% (6.3%, 2/32)
20-40% (3.1%, 1/32)
>40% (68.8%, 22/32)
Frequency Peri-incisional
Antimicrobial Use
Total = 28
Amikacin (32.1%, 9/28)
Amoxicillin (3.6%, 1/28)
Ampicillin (3.6%, 1/28)
Cefazolin (7.1%, 2/28)
Ceftiofur (3.6%, 1/28)
Ceftriazone (3.6%, 1/28)
Cephapirin (3.6%, 1/28)
Enrofloxacin (3.6%, 1/28)
Gentamicin (14.3%, 4/28)
Neomycin (7.1%, 2/28)
Penicillin (unspecified) (10.7%, 3/28)
Potassium penicillin (3.6%, 1/28)
Sodium penicillin (3.6%, 1/28)
Selection Peri-incisional
Antimicrobial Use
AB
C
Tot al = 113
Yes (11.5%, 13/113)
No (88.5%, 100/113)
Intra-abdominal Antimicrobial Use
Total = 12
Gentamicin (16.7%, 2/12)
Potassium penicillin (41.7%, 5/12)
Sodium penicillin (8.3%, 1/12)
Penicillin (unspecified) (8.3%, 1/12)
Neomycin (8.3%, 1/12)
Ampicillin (8.3%, 1/12)
Cefazolin (8.3%, 1/12)
Selection Intra-abdominal Antimicrobial Use
Tot al = 17
<10% (35.3%, 6/17)
10-20% (11.8%, 2/17)
20-40% (17.6%, 3/17)
>40% (35.3%, 6/17)
Frequency Intra-abdominal Antimicrobial Use
AB
C
Figure 7.
Intra-abdominal antimicrobial use, including (
A
) reported usage (yes/no), (
B
) frequency of
use if reported, and (
C
) antimicrobial selection if used. Total number of responses per question is
indicated beneath each chart. Respondents were not limited in number to antimicrobial selection.
4. Discussion
This study contributes to the current understanding of antimicrobial use in the pe-
rioperative period for exploratory celiotomy by equine surgeons and internal medicine
specialists. As antimicrobial resistance is considered an emerging ‘One Health’ medical
issue in both human and veterinary medicine, periodic auditing of clinical practices is
warranted. The results of this survey highlight significant variation in approaches to
antimicrobial administration, similar to previous studies detailing differences between
institutions as well as between intended and actual use [
9
,
16
,
20
,
21
]. These findings repre-
sent a description of current practice rather than evidence to support antimicrobial dosing
recommendations; however, surveys of clinical practice have been used as an established
approach in human medicine to guide informed decision-making when there is insufficient
data from case-controlled clinical trials to provide evidence-based guidelines, as is the
case for many instances where antimicrobials are used in equine clinical practice [
22
]. The
limited number of antimicrobials approved for use in horses presents a challenge to equine
practitioners, resulting in frequent extra-label and compounded drug use [
23
]. Although
survey enrollment in this study was limited, as has been the case with other recently pub-
lished analyses of equine practice [
24
–
26
], these findings represent an updated picture of
the clinical use of antimicrobials by equine specialists in the United States.
Guidelines for antibiotic selection in equine patients have been adapted from human
medicine and typically include the implementation of early-generation broad-spectrum an-
timicrobials given intravenously prior to surgery [
1
,
5
,
20
,
27
]. The findings of this study were
generally in concordance with that recommendation as well as previous reports [
9
], with
two drug classes being administered most commonly preoperatively, frequently potassium
penicillin and gentamicin [
28
]. As surgical site infections (SSI) are the second most com-
monly reported short-term complication following celiotomy (after persistent postoperative
signs of colic) [
29
], antimicrobial selection should be dictated by efficacy against common
pathogens. Previous reports of SSI in horses have identified Enterobacteriaceae,Enterococcus,
Staphylococcus, and Streptococcus as commonly identified bacterial isolates [30–32].
Aminoglycosides such as gentamicin are effective against Enterobacteriaceae and, in
some instances, Staphylococci, although systemic administration is considered extra-label use
as the only FDA-approved indication for horses is via intra-uterine infusion [
28
]. Penicillin
Animals 2023,13, 1433 9 of 16
is also used extra-label to treat infections in horses, including Streptococcus. However, in one
study evaluating all isolates cultured in equine celiotomy SSI, penicillin-resistant isolates
accounted for 92%, while an additional 18% were gentamicin-resistant [
30
–
32
]. Other
studies have corroborated these findings, indicating a significant increase in the percentage
of resistant equine isolates over time [
33
–
37
] and greater consideration of drugs considered
to be critically important for human use [
1
]. Additionally, positive intraoperative cultures
of the incision have not been shown to be predictive of SSI, and when SSI did occur, it
was due to a different bacterial isolate in that study [
30
,
31
]. Furthermore, a variety of
bacterial species may be isolated from laparotomy incisions peri-operatively without the
development of SSI, indicating that while contamination of the incision peri-operatively
may be one mechanism by which SSI occurs, evaluation of other mechanisms such as
bacteremia postop warrant further investigation [
30
,
31
]. While the selection of early-
generation broad-spectrum antimicrobials appears appropriate based on a recent review of
the literature for ‘clean-contaminated’ procedures, further consideration of the timing of
the first administration and postoperative duration is warranted.
The timing of initial antimicrobial administration has been recommended to be within
60 min before the first incision based on human guidelines [
37
] but has historically been
cited as challenging in equine practice for a variety of reasons, including hospital policies,
the emergent nature of surgery in some instances, and concern for hypotension when ad-
ministered following anesthetic induction [
9
,
20
,
21
]. In one tertiary equine referral hospital
where clinical audits of antimicrobial recording were performed to raise awareness of the
timing of antimicrobial dose prior to surgery, improvement was shown between audits
for elective arthroscopies but not for emergency laparotomies, highlighting that in many
cases, lack of compliance with drug guidelines is likely the result of challenges faced by
personnel working in critical conditions rather than a lack of awareness or an unwillingness
to comply [
20
]. Evidence in humans undergoing emergency surgery supports the concept
that achieving high concentrations of antimicrobials at the time of incision and throughout
surgery is likely more important in reducing infection than the duration of antimicrobial
therapy postoperatively [
38
], which encourages increased awareness of drug timing relative
to surgery when possible.
Intraoperative redosing of antimicrobials for prolonged surgical procedures where con-
centrations of prophylactic antimicrobials may decrease below MIC for common pathogens
has been described as similarly crucial to initial drug administration in human surgery to re-
duce infection [
39
]. Human guidelines indicate redosing is warranted for procedures lasting
longer than two drug half-lives or with significant blood loss (i.e., in humans
>1.5 L)
[
40
–
42
].
Further evidence to support this concept has been demonstrated in multiple reports [
43
–
45
]
and ongoing clinical trials assessing optimal timing for abdominal surgery specifically [
46
].
However, noncompliance with this aspect of antimicrobial use has been similarly recog-
nized in multiple studies as an area where improvement may be made [
47
–
50
]. Similarly, in-
traoperative redosing is reported to be infrequently performed in equine colic surgery [
9
,
19
],
including in the authors’ practice, which was also reflected in the results of this survey.
The half-life of penicillin, one of the most commonly used drugs in this survey and a time-
dependent antimicrobial, is 30 to 40 min in horses, indicating subtherapeutic levels may be
reached during critical stages of longer procedures, such as resection and anastomoses, and
recovery from general anesthesia [
9
,
19
]. The rationale for not performing intraoperative
redosing has been cited as being due to the perceived risk of hypotension, particularly
with penicillin drugs, by anesthesiologists, a lack of awareness of drug half-lives by clin-
icians, or inadvertent noncompliance intraoperatively [
9
,
51
]. However, evidence in the
human literature suggests that stricter adherence to appropriate intraoperative redosing
recommendations may reduce the risk of incisional infection, although this requires further
investigation in equine practice specifically [
19
]. Compliance with redosing of intraopera-
tive antimicrobials in human surgery has been shown to be objectively improved through a
combined approach involving the implementation of clearly defined guidelines, increased
Animals 2023,13, 1433 10 of 16
education of healthcare providers, and automated paging systems prompting redosing,
which could also be integrated into veterinary surgery [52–54].
General guidelines regarding antimicrobial duration in veterinary medicine support
the idea that they should be administered for the shortest effective duration to reduce the
risk of the development of resistant pathogens [
27
,
55
]. In equine celiotomy procedures,
duration of administration has anecdotally been administered to reduce the risk of surgical
site infection, pneumonia, and peritonitis. When considering surgical site infection specifi-
cally, prolonged antimicrobial use beyond 24 h postoperatively in humans did not reduce
the incisional complication rate even in surgeries classified as ‘dirty’ [
40
]. This concept has
been supported by several recent papers in the equine literature that did not demonstrate
additional benefits to prolonged antimicrobial administration following equine laparo-
tomy [
11
,
15
]. Durward-Akhurst reported comparable incisional complication rates with
72 versus 120 h of antimicrobial administration, concluding that no benefit of using a
prolonged period of antimicrobials should be expected [
15
]. As colic surgery is generally
considered a clean-contaminated procedure, protocols in human medicine would suggest
that it is possible to reduce use to 24 h postoperatively [
5
]. No additional benefit beyond
a single prophylactic dose versus 120 h of administration was found in another recent
pilot study in horses, although it was acknowledged that the power calculation indicated
that a larger sample size enrolled over a longer study period would be necessary to draw
general conclusions [
11
]. Another study evaluating temporal changes in antimicrobial
regimens for equine colic surgery also indicated no additional benefit to administering
antimicrobials past a single preoperative dose [
55
]. However, whether these findings can
be extrapolated to equine patients undergoing enterotomy or resection and anastomosis
without increased risk for peritonitis requires further investigation. Additionally, as intu-
bation may be performed in painful patients without standard oral rinsing in some cases,
increased gross contamination of the lower airway may prompt longer antibiotic durations
postoperatively to reduce the perceived risk of pneumonia. Furthermore, individual case
factors (e.g., pyrexia, incisional or catheter-associated complications, bloodwork, preopera-
tive immune statuses such as pars pituitary intermedia dysfunction, or perceived risk of
pulmonary complications from intubation) are frequently considered by clinicians when
determining antimicrobial duration, as was reflected in this report, rather than applying
standard lengths of time for each case. Finally, it is recognized that other factors related to
case management are within the clinician’s control (e.g., subcutaneous lavage, skin closure
techniques, abdominal bandaging). However, antimicrobial duration also plays a role in
reducing surgical site infection [56].
Another consideration that has been raised with the extended duration of antimi-
crobial administration is regarding the prevention of intra-abdominal adhesion develop-
ment, as one study indicated that administration of the combination of 72 h of potassium
penicillin, gentamicin, and flunixin meglumine prevented abdominal adhesion formation
in foals with experimental ischemia [
57
]. However, a shorter duration of antimicrobial
administration was not evaluated, and therefore conclusions could not be definitively
drawn regarding the optimal drug administration length to reduce adhesions [
57
]. Taken
together, these findings support the notion that, as most colic surgeries are classified as
‘clean-contaminated,’ antimicrobial prophylaxis is indicated, but that extended duration
may not be necessary, and larger studies are needed to draw conclusions regarding pro-
tocols for specific indications. Given the expense of prolonged antimicrobial treatment
and increased concern with antimicrobial resistance, a more selective approach to drug
administration is indicated [19].
Postoperative complications most frequently reported in this survey included fever
and incisional infection. Of note, the prevalence of mild postoperative pyrexia (>38.3
◦
C)
is reportedly high (85%) in the early postoperative period (<48 h) and does not equate
to bacterial infection nor the necessity for long-term antimicrobial use necessarily [
5
,
19
].
Prevalence of SSI has been previously reported to be 10–42%, similar to findings self-
reported here as predominantly <10 or 10–20% of cases, although variability in reporting is
Animals 2023,13, 1433 11 of 16
likely due in part to different definitions of SSI used, the fact that estimates were reported
here rather than recorded incidences, and follow-up available to clinicians upon dismissal
from the hospital [
15
,
19
,
29
–
31
,
58
]. Infection is known to impact the length of stay and
therefore the cost of care and result in reduced long-term survival [
19
]. Notably, client-
reported satisfaction with the celiotomy procedure was not shown to be reduced with the
development of postoperative infection, except in cases of Salmonellosis in one study at a
tertiary referral hospital [19].
The incidence of postoperative complications, in addition to survival rate and prognos-
tic indices (which were not surveyed in this study), may not be comparable across regions
due to differences in management, climate, or diet (e.g., types of forage) that may influence
the onset of abdominal colic [
59
–
62
]. However, in this study, several common complications
were reported with a similar frequency to recent reports [
63
]. Other complications that
have been infrequently reported following colic surgery were not specifically questioned in
this survey nor mentioned by participants, including penicillin-induced immune-mediated
hemolytic anemia [
11
,
64
], sinus infection [
65
], hemoperitoneum [
63
], or those that may be
perceived as secondary to the anesthetic event itself (e.g., myopathy, fracture). Furthermore,
it is acknowledged that complication rates (e.g., for surgical site infection) postoperatively
have been shown to be influenced by multiple other variables outside of the clinician’s
control, which could not be accounted for in this survey format. These include such factors
as the season of the year, body weight, age, duration of colic signs, physical examination
findings, bloodwork, peritoneal fluid analysis findings on admission, whether small intesti-
nal resection was necessary, or whether the emergent nature of the condition necessitated
surgery outside of normal working hours [
30
,
31
,
56
,
65
–
68
]. Due to the factors discussed,
reported complication rates were not correlated with individual antimicrobial protocols in
this survey.
Additional antimicrobial therapy via routes other than systemic administration (i.e., peri-
incisional and intra-abdominal) was reported in 25 and 12% of cases in this survey, re-
spectively, although survey respondents were not asked to clarify whether the usage was
intended to prevent or treat infection (i.e., intra-abdominal use in cases where celiotomy
was performed to treat established peritonitis) [
69
]. Evidence for administration by these
routes is limited in equine practice, and appropriate doses to minimize local cytotoxicity
have not been determined given that administration by either route is extra-label. An-
timicrobial inclusion in lavage fluids in experimental studies in horses was reported to
induce a mild, transient inflammatory response to peritoneal fluid, although efficacy has
not been definitively assessed in equine studies to the authors’ knowledge [
70
]. Povidine-
iodine solutions administered intraabdominally further induced chemical peritonitis in
horses [
70
]. Recent meta-analyses in human surgery may support a potential benefit to
intra-operative intra-cavitary lavage and wound/incision irrigation, with reduced SSI in
groups receiving any surgical site lavage versus none, and those receiving antibacterial
versus non-antibacterial lavage interventions, antibacterial versus povidine-iodine or saline,
and pulsatile versus standard lavage, although reports included were conflicting [
71
,
72
].
However, current guidelines by the Surgical Infection Society on the management of ab-
dominal infection do not include recommendations for antimicrobial use beyond systemic
administration [
73
]. Further investigation of adjunctive antimicrobial techniques in equine
practice for abdominal surgery would be warranted in light of antimicrobial stewardship
and to assess local cytotoxicity and efficacy prior to administration.
The limitations of this study include the self-reported nature of the findings and the
likely low survey response rate. Whether individual clinicians based their responses on
objective personal audits performed recently or were relying on clinical impressions of
their practice was not recorded. The number of survey responses received was lower than
expected, indicating that a minority of the populations contacted responded, which is
similar to other recently published surveys in equine practice [
24
–
26
]. In addition, the
electronic survey was sent only to ACVS and ACVIM diplomates, which may have been
selected for response bias, and it is acknowledged that the results may not reflect usage by
Animals 2023,13, 1433 12 of 16
individuals in other colleges or non-specialists who may use antimicrobials perioperatively
for equine celiotomy. When assessing complications, other factors that may influence the
surgical site infection rate, for instance, were not surveyed as antimicrobial usage was
the primary focus of this work (e.g., abdominal bandaging, skin closure technique, and
suture selection, quality of anesthetic recovery, IV fluid therapy, intraoperative arterial
pressure) [
19
,
57
,
74
–
77
]. Not all participants answered all questions posed, indicating
some participation bias. Furthermore, the study, as designed, likely did not capture all
possible complications or those infrequently reported (e.g., sinus infection, pneumonia,
hemoperitoneum) and did not consider potential complications of any surgical procedure
under general anesthesia in horses (e.g., myopathy) [
63
,
65
]. Despite these limitations, this
study provided important insight into the current clinical use of antimicrobials for equine
abdominal surgery by large animal specialists.
5. Conclusions
Clinical auditing has been demonstrated to improve the quality of patient care in
multiple care settings [
78
,
79
] and may be applied in equine celiotomies to improve the
completeness of record keeping and raise awareness of current recommendations for an-
timicrobial prophylaxis. Identifying members of the anesthesia and/or perioperative care
teams as responsible for antimicrobial administration may bring the timing of the first dose
closer to the surgical incision. A greater emphasis on the timing of surgical preparation
(e.g., removing hair or surface contamination overlying the celiotomy incision site) prior to
induction and premedication may reduce the lag time between antimicrobial administra-
tion and the initiation of surgery. However, it is recognized that the lack of improvement in
one study with antimicrobial administration for emergency procedures following a clinical
audit [
20
] highlights the complexity of the situation for clinicians treating emergency ce-
liotomy. The consciousness of antimicrobial protocols in light of increased antimicrobial
resistance in veterinary practice and the completeness of medical records from a legal per-
spective is of mounting importance [
20
]. With this in mind, periodic audits of actual versus
intended practices may provide clinical benefits to improve fiscal responsibility to clients,
reduce antimicrobial-associated complications, and improve antimicrobial stewardship
in light of increased drug resistance. Larger case-controlled clinical trials in horses are
indicated to determine and compare the efficacy between antimicrobial protocols with
regard to intraoperative redosing and antimicrobial duration postoperatively for specific
surgical indications.
Author Contributions:
L.P. and G.G. contributed to the conceptualization. L.P., G.G., M.R., G.L. and
D.H. contributed to the methodology. L.P. and G.G. contributed to formal analysis, investigation, and
data curation. L.P., G.G. and M.R. contributed to the writing (original draft preparation). All authors
contributed to writing (review and editing), visualization, supervision, project administration, and
funding acquisition. All authors have read and agreed to the published version of the manuscript.
Funding:
This research was funded by a Young Investigator Grant from the Center for Companion
Animal Studies at Colorado State University.
Institutional Review Board Statement: Not applicable.
Informed Consent Statement:
Completion of the questionnaire by veterinary professionals was
taken as informed consent.
Data Availability Statement: The data is contained within the article.
Acknowledgments:
The authors thank the members of the American Colleges of Veterinary Internal
Medicine and Surgery who participated in the survey described herein.
Conflicts of Interest: The authors declare no conflict of interest.
Animals 2023,13, 1433 13 of 16
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