Prevalence of complications associated with use of the Henderson equine castrating instrument.

BACKGROUND: Castration is one of the most common surgical procedures performed in the horse. Complication rate and types of complications associated with use of the Henderson equine castrating instrument have not been determined. OBJECTIVE: To determine the complication rate and type of complications encountered when using the Henderson equine castrating instrument in equine ambulatory practice. STUDY DESIGN: Retrospective case series. METHODS: Medical records of horses undergoing routine castration using the Henderson drill were identified and evaluated for the occurrence of complications. The relationship between potential risk factors and complications was examined using basic descriptive statistics and quantified by means of logistic regression. RESULTS: Of 252 horses in the study population, 27 (10.7%) developed a complication after surgery; 25 of which were nonlife-threatening and responded to medical management. Two complications, one each of wound botulism and evisceration, resulted in euthanasia. Age at the time of castration was significantly associated with the occurrence of (P = 0.005, Wilcoxon rank sum test) complications. Compared to younger horses, the odds of having a complication were significantly greater (OR 2.99, 95% CI 1.27-7.0; P = 0.01) for horses of 4 years of age or more. MAIN LIMITATIONS: The retrospective nature of this study. There is also a lack of direct comparison between different castration methods. CONCLUSIONS: The Henderson equine castrating instrument is an acceptable alternative to traditional emasculators. Its use is associated with a low rate of complications (8.3%) in young horses (≤3 years of age) compared to older horses (21.3%) and a very low rate of serious complications (0.8%) in all ages of horses.

Are horse age and incision length associated with surgical site infection following equine colic surgery?

It is our clinical impression that age and incision length are more strongly associated with surgical site infection (SSI) following colic surgery than skin closure or wound protection method. Therefore, the objective of this observational clinical cohort study was to identify the risks for SSI in horses undergoing colic surgery. Data collection included pre-, intra-, and postoperative variables. Variables with P < 0.2 following univariable analysis were used in a logistic regression multivariable model. Variables with P <0.05 were included in the final model. Odds ratios (OR; 95% confidence intervals, 95% CI) were determined. The area under the curve (AUC) for the receiver-operator characteristic was calculated. The final multivariable model included breed (P = 0.008), incision length (P = 0.004), surgical procedure classification (P <0.001), and postoperative (PO) colic (P = 0.037; overall model P <0.001, and AUC was 0.81 [excellent discrimination between SSI vs. no SSI]). Warmbloods (OR 12.0; 95% CI 2.7-74.8), American breeds (OR 6.4; 95% CI 1.2-43.0), and Thoroughbreds (4.5; 95% CI 1.1-25.5) more commonly had SSI than other breeds (ponies/miniature horses, Draft breeds, Standardbreds, Arabians, and Crossbreeds [referent]). A higher SSI rate was associated with incision lengths >27 cm (3.7; 95% CI 1.5-9.9), heavily contaminated procedures (12.0; 95% CI 3.3-49.9), and horses with PO colic (2.7; 95% CI 1.1-6.8). SSI appeared to be more common after heavily contaminated procedures and in horses with PO colic, which probably resulted in more incisional contamination and trauma. Some breeds appeared to have higher odds of SSI. Age was not associated with SSI. The risk of developing SSI was higher for horses with an incision >27 cm; therefore, surgeons are encouraged to use the minimum incision length required to accomplish the necessary abdominal exploration and bowel manipulation in the safest manner possible.

Comparison of short- and long-term complications and survival following jejunojejunostomy, jejunoileostomy and jejunocaecostomy in 112 horses: 2005-2010.

REASONS FOR PERFORMING THE STUDY: There is disagreement among surgeons over whether jejunoileostomy (JI) or jejunocaecostomy (JC) is the better method of anastomosis following proximal ileal resection. OBJECTIVE: To compare short- and long-term complications and outcome in horses undergoing jejunojejunostomy (JJ), JI and JC and to test the hypotheses that a higher proportion of horses undergoing JI would have short-term complications and mortality compared with horses undergoing JC or JJ and that JC would be associated with a higher long-term mortality and occurrence of colic. STUDY DESIGN: Retrospective cross-sectional study. METHODS: Medical records of horses undergoing celiotomy for a small intestinal obstruction and JJ, JI or JC from 2005 to 2010 were reviewed. Post operative complications were recorded. Short-term outcome was alive vs. dead at hospital discharge and was analysed using a Chi-squared test. Long-term follow-up was obtained and a Kaplan-Meier estimate of the survivor function was performed. RESULTS: There were 112 horses included. A higher proportion of JI horses had a repeat celiotomy during hospitalisation compared with horses undergoing JC. The number of horses alive at hospital discharge was not different between groups: JJ 79% (95% confidence interval [CI] 68-90%), JI 78% (95% CI 61-96%), JC 83% (95% CI 71-96%). Among horses discharged with long-term follow-up, more horses had colic after JC compared with JJ or JI. Long-term post discharge survival based on the Kaplan-Meier survivor function was lower for horses undergoing JC than JJ or JI (P = 0.04). CONCLUSION: While there was no difference in short-term outcome between groups, more horses with JI underwent a repeat celiotomy during hospitalisation. Horses with a JC were more likely to have long-term complications with colic. Horses that were subjected to euthanasia because of colic within 12 months of hospital discharge either had a JC or repeat celiotomy. The results suggest that, when possible, a JI may be the preferred method of anastomosis based on more favourable survival and lower occurrence of colic long term.

Syndromic surveillance for evaluating the occurrence of healthcare-associated infections in equine hospitals.

REASONS FOR PERFORMING STUDY: Methods that can be used to estimate rates of healthcare-associated infections and other nosocomial events have not been well established for use in equine hospitals. Traditional laboratory-based surveillance is expensive and cannot be applied in all of these settings. OBJECTIVES: To evaluate the use of a syndromic surveillance system for estimating rates of occurrence of healthcare-associated infections among hospitalised equine cases. STUDY DESIGN: Multicentre, prospective longitudinal study. METHODS: This study included weaned equids (n = 297) that were admitted for gastrointestinal disorders at one of 5 participating veterinary referral hospitals during a 12-week period in 2006. A survey form was completed by the primary clinician to summarise basic case information, procedures and treatments the horse received, and whether one or more of 7 predefined nosocomial syndromes were recognised at any point during hospitalisation. Adjusted rates of nosocomial events were estimated using Poisson regression. Risk factors associated with the risk of developing a nosocomial event were analysed using multivariable logistic regression. RESULTS: Among the study population, 95 nosocomial events were reported to have occurred in 65 horses. Controlling for differences among hospitals, 19.7% (95% confidence interval, 14.5-26.7) of the study population was reported to have had at least one nosocomial event recognised during hospitalisation. The most commonly reported nosocomial syndromes that were unrelated to the reason for hospitalisation were surgical site inflammation and i.v. catheter site inflammation. CONCLUSIONS: Syndromic surveillance systems can be standardised successfully for use across multiple hospitals without interfering with established organisational structures, in order to provide useful estimates of rates related to healthcare-associated infections.

Using syndromic surveillance to estimate baseline rates for healthcare-associated infections in critical care units of small animal referral hospitals.

BACKGROUND: Expected rates of healthcare-associated infections (HCAI) have not been established in veterinary hospitals. Baseline rates are critically needed as benchmarks for quality animal care. OBJECTIVE: To estimate the occurrence of events related to HCAI identified using a standardized syndromic surveillance system in small animals in critical care cases at referral hospitals. ANIMALS: Weaned dogs and cats (n = 1,951) that were hospitalized in the critical care unit of referral teaching hospitals during a 12-week period. METHODS: Multicenter, prospective longitudinal study. A survey was completed for all enrolled animals to record basic demographics, information about procedures and treatments that animals received, and to document the occurrence of defined nosocomial syndromes. Data were analyzed to identify risk factors associated with the occurrence of these nosocomial syndromes. RESULTS: Controlling for hospital of admission, 16.3% of dogs (95% confidence intervals [CI], 14.3-18.5) and 12% of cats (95% CI, 9.3-15.5) were reported to have had ≥ 1 nosocomial syndrome occur during hospitalization. Risk factors found to have a positive association with the development of a nosocomial syndrome were longer hospital stays, placement of a urinary catheter, surgical procedures being performed, and the administration of antiulcer medications and antimicrobial drugs excluding those given perioperatively. CONCLUSIONS AND CLINICAL IMPORTANCE: Syndromic surveillance systems can be successfully standardized for use across multiple hospitals to effectively collect data pertinent to HCAI rates and risk factors for occurrence.

Short communication: Survey of animal-borne pathogens in the farm environment of 13 dairy operations.

A survey was conducted on 13 dairies to determine the occurrence of 5 animal-borne pathogens (Salmonella enterica, Escherichia coli O157:H7, Campylobacter jejuni, Mycobacterium avium ssp. paratuberculosis, and Cryptosporidium parvum) and their distributions across farm elements (feces, bedding, milk filters, stored manure, field soil, and stream water). Presence of C. parvum was measured only in feces and stored manure. All but one farm were positive for at least one pathogen species, and 5 farms were positive for 3 species. Escherichia coli O157:H7 was detected on 6 farms and in all farm elements, including milk filters. Mycobacterium avium ssp. paratuberculosis was detected on 10 of 13 farms and in all farm elements except for milk filters. Salmonella enterica and C. jejuni were detected at lower frequencies and were not identified in soil, stream water, or milk filters on any of the 13 farms. Cryptosporidium parvum was detected in feces but not in stored manure. Stored manure had the highest occurrence of pathogens (73%), followed by feces (50%), milk filters, bedding, soil, and water (range from 23 to 31%). Association of pathogen presence with farm management factors was examined by t-test; however, the small number of study farms and samples may limit the scope of inference of the associations. Pathogens had a higher prevalence in maternity pen bedding than in calf bedding, but total pathogen occurrence did not differ in calf compared with lactating cow feces or in soils with or without manure incorporation. Herd size and animal density did not appear to have a consistent effect on pathogen occurrence. The extent of pathogen prevalence and distribution on the farms indicates considerable public health risks associated with not only milk and meat consumption and direct animal contact, but also potential dissemination of the pathogens into the agroecosystem.

Post operative infection, pyrexia and perioperative antimicrobial drug use in surgical colic patients.

REASONS FOR PERFORMING STUDY: Infections are common complications in post operative colic patients. It is the impression of some surgeons that pyrexia in the early post operative period is a sign of infection and appropriate timing of perioperative antimicrobials will decrease the incidence of post operative infection. OBJECTIVE: To determine the association between 1) post operative pyrexia and development of infection and 2) perioperative antimicrobial drug use and infection rate in post operative colic patients. METHODS: Medical records of patients undergoing surgical treatment for colic were reviewed. Horses recovering from surgery and surviving >48 h were included. Data relating to case details, duration of surgery, post operative infection, peri- and post operative antimicrobial administration, presence, intensity and duration of pyrexia, were recorded. Data were analysed using standard statistical methods for simple comparisons between groups and by logistic regression for more complex comparisons. RESULTS: One-hundred-and-thirteen horses were included in the final analyses, 48 (43%) of which were diagnosed with a post operative infection. Duration of surgery and anaesthesia were associated with post operative infection. Eighty-five percent of horses (n = 96) exhibited pyrexia (rectal temperature >38.3°C) post operatively. Peak temperature >39.2°C, time post surgery to peak temperature >48 h and duration of pyrexia >48 h were significantly associated with infection. In a combined model, time to first pyrexic >48 h post surgery, peak temperature and time to peak >48 h were equally weighted and the model's positive predictive value for post operative infection was 72%. Timing and dose rate of preoperative antimicrobials were not associated with infection but duration of post operative antimicrobial drug use was. CONCLUSION AND CLINICAL RELEVANCE: Slight to mild pyrexia (38-39.4°C) in the early post operative period is not necessarily associated with impending bacterial infection in colic patients and the use of antimicrobials in these patients may be costly and unnecessary.

Survival characteristics of Salmonella enterica serovar Newport in the dairy farm environment.

Multi-drug resistant (MDR) Salmonella enterica serovar Newport (S. Newport) has established a reservoir in dairy cattle. Infected herds suffer significant mortality in both adult and young animals, posing a considerable economic loss to producers. Land application of manure from infected animals may further spread the pathogen into the agroecosystem, causing public health concerns. Previous work by our group demonstrated that the organism persisted in manure and manured soil for 6 to 10 mo under laboratory conditions. In the present study, we determined the survival characteristics of MDR S. Newport in a dairy lagoon, compost pile, and soil of a grass field under natural conditions using environmental sentinel chambers with an initial concentration of S. Newport around 7 log(10) per gram. In the static compost pile at 64 °C, S. Newport was eliminated within 18 h. In the dairy effluent lagoon, the pathogen survived for >137 d, whereas in the field soil, the organisms persisted for over 276 d. The survival of MDR S. Newport in both the lagoon and field soil followed a pattern of (1) an increase or plateau for a few days, (2) log-linear decline for 6 to 13 wk, and (3) a long tailing phase at low and variable concentration for 4 to 9 mo. Log reduction times (days required for 90% decrease in concentration) based on the log-linear decline phase were 7 d in the lagoon and 14 to 20 d in the soil. Conditions leading to faster inactivation during the initial phase do not necessarily translate into a quicker elimination of the pathogen. Regression models of the log-linear phase may be inaccurate for estimating complete pathogen elimination.