Evaluation of the Efficacy of Disinfectant Footmats for the Reduction of Bacterial Contamination on Footwear in a Large Animal Veterinary Hospital.

BACKGROUND: Infection control is critical to providing high-quality patient care. Many veterinary teaching hospitals (VTHs) utilize footbaths or footmats at entrances and key control points throughout the facility to decrease trafficking of pathogenic microorganism on contaminated footwear. HYPOTHESIS/OBJECTIVES: To compare efficacy of 4 disinfectants used in footmats for decreasing bacterial contamination of footwear in a large animal hospital. ANIMALS: A single adult dairy cow was housed in a stall for 4 days to facilitate stall contamination with fecal material. METHODS: Overboots were experimentally contaminated with organic material in a standardized manner. Each boot was randomly assigned to 1 of 5 treatments (no treatment, or exposure to 1 of 4 disinfectants: an accelerated peroxygen [AHP], a peroxygen [VIRKON], a quaternary ammonium [QUAT], and a phenolic disinfectant [PHENOLIC]) by stepping on a soaked footmat and collecting samples from boot soles. Generalized linear modeling was used to analyze differences in bacterial counts. RESULTS: Reductions in colony-forming units (CFUs) on treated boots ranged from no detectable reduction to 0.45 log10 and varied by disinfectant. Percentage reductions in total bacterial counts generally were larger (albeit still modest) for AHP and QUAT disinfectants (range 37-45%) and smallest for the PHENOLIC (no detectable reduction). CONCLUSIONS AND CLINICAL IMPORTANCE: In general, use of disinfectant footmats was associated with significant reductions in viable bacteria on overboots-albeit with variable efficacy. Footmats may be useful adjuncts to cleaning and disinfection programs for decreasing trafficking of microorganisms throughout VTHs but should not be considered as a sole prevention method.

Comparison of disinfectant efficacy when using high-volume directed mist application of accelerated hydrogen peroxide and peroxymonosulfate disinfectants in a large animal hospital.

REASONS FOR PERFORMING STUDY: Effective decontamination of animal holding environments is critical for providing high quality patient care and maintaining a safe working environment. Disinfection of animal holding environments is a significant challenge during times of epidemic disease. OBJECTIVES: The purpose of this study was to evaluate the disinfectant efficacy of 3 strategies for high-volume directed mist application of accelerated hydrogen peroxide and peroxymonosulfate disinfectants; 4.25% accelerated hydrogen peroxide (Accel(®) ; AHP) at a 1:16 dilution and single and double applications of 2% peroxymonosulfate solution (Virkon-S(®) ; VIR-1 and VIR-2) for decontamination of a large animal hospital environment. STUDY DESIGN: Experiment. METHODS: After cleaning and disinfection of the hospital environment, transparencies experimentally contaminated with known concentrations of Staphylococcus aureus, Salmonella enterica and Pseudomonas aeruginosa were placed on vertical surfaces. Disinfectant solution was applied by directed mist application and, after 30 min of contact time, transparencies were collected and individually placed into tubes containing 10 ml Dey-Engley broth. The process was repeated for each disinfectant. Tenfold dilutions of each sample were plated onto tryptic soy blood agar with 5% sheep blood. Bacterial counts from transparencies exposed to disinfectants were compared with counts from control transparencies (unexposed to disinfectants) to evaluate reduction in colony forming units. RESULTS: The least squares mean reduction (log10 ) in colony forming units (CFUs) for S. aureus and P. aeruginosa was 1.5-2.5 logs and approximately 0.8-1.0 logs for S. enterica. Reductions were generally largest for VIR-2 and smallest for AHP, although these differences were not all statistically significant and the magnitude of differences may not be clinically relevant. CONCLUSIONS: For the organisms evaluated, all 3 disinfectants applied as a directed mist were effective at reducing CFUs in a veterinary hospital environment. Effective disinfection using this method of application is dependent on adequate cleaning prior to application, and use of adequate volumes of disinfectant.

Rapid Salmonella detection in experimentally inoculated equine faecal and veterinary hospital environmental samples using commercially available lateral flow immunoassays.

REASONS FOR PERFORMING STUDY: Salmonella enterica is the most commonly reported cause of outbreaks of nosocomial infections in large animal veterinary teaching hospitals and the closure of equine hospitals. Rapid detection may facilitate effective control practices in equine populations. Shipping and laboratory testing typically require ≥48 h to obtain results. Lateral flow immunoassays developed for use in food-safety microbiology provide an alternative that has not been evaluated for use with faeces or environmental samples. OBJECTIVES: We aimed to identify enrichment methods that would allow commercially available rapid Salmonella detection systems (lateral flow immunoassays) to be used in clinical practice with equine faecal and environmental samples, providing test results in 18-24 h. STUDY DESIGN: In vitro experiment. METHODS: Equine faecal and environmental samples were inoculated with known quantities of S. enterica serotype Typhimurium and cultured using 2 different enrichment techniques for faeces and 4 enrichment techniques for environmental samples. Samples were tested blindly using 2 different lateral flow immunoassays and plated on agar media for confirmatory testing. RESULTS: In general, commercial lateral flow immunoassays resulted in fewer false-negative test results with enrichment of 1 g faecal samples in tetrathionate for 18 h, while all environmental sample enrichment techniques resulted in similar detection rates. The limit of detection from spiked samples, ∼4 colony-forming units/g, was similar for all methods evaluated. CONCLUSIONS: The lateral flow immunoassays evaluated could reliably detect S. enterica within 18 h, indicating that they may be useful for rapid point-of-care testing in equine practice applications. Additional evaluation is needed using samples from naturally infected cases and the environment to gain an accurate estimate of test sensitivity and specificity and to substantiate further the true value of these tests in clinical practice.

Detection of different serotypes of Salmonella enterica in experimentally inoculated equine fecal samples by commercially available rapid tests.

BACKGROUND: Salmonella enterica can significantly impact management of animal facilities. Comprehensive screening is essential for effective control in high-risk populations. Availability of reliable point-of-care diagnostic tests would facilitate these efforts. HYPOTHESIS/OBJECTIVES: Compare the ability of commercially available rapid diagnostic assays (2 lateral flow immunoassays [LFIs], DNA hybridization [DNAH], real-time PCR [qPCR]), and culture to detect common serotypes of S. enterica in feces. ANIMALS: n/a. METHODS: In an experimental study, 112 S. enterica isolates were randomly selected from the 10 most common serotypes recovered at a veterinary hospital. Archived isolates were amplified in broth and standardized inocula (100 colony forming units) were incubated with equine feces in tetrathionate broth (TET). Cultures were tested in a blinded fashion by using LFIs, DNAH, qPCR, and culture. RESULTS: The LFIs detected 84% and 67% of isolates, respectively, but reactivity varied among serotypes. Both reacted poorly with serotype Cerro (Group K) isolates, and 1 LFI did not react with any serotype Mbandaka (Group C1) or Montevideo (Group C1) isolates. DNAH detected 94% of isolates, whereas culture and qPCR most reliably detected all serotypes. False-positive results were obtained for 4 negative controls by using DNAH and 1 negative control by using qPCR, but LFIs and culture had no false-positive results. CONCLUSIONS AND CLINICAL IMPORTANCE: Culture, qPCR, and DNAH were effective in detecting most Salmonella isolates, but have limited application at point-of-care settings. LFIs are appealing as point-of-care tests because of low cost and ease of use, but limited detection of some serotypes needs to be evaluated with samples obtained from naturally infected animals.

Acquired urethral obstruction in New World camelids: 34 cases (1995-2008).

OBJECTIVE: Document the clinical features, short- and long-term outcomes and prognostic factors in New World camelids with acquired urethral obstruction. DESIGN: Retrospective case study. METHODS: Case data from medical records of 34 New World camelids presenting with acquired urethral obstruction were collected and follow-up information on discharged patients was obtained. Associations with short- and long-term survival were evaluated using Wilcoxon rank-sum tests, exact-logistic regressions and Kaplan-Meier survival curves. RESULTS: Of the 34 New World camelids 23 were intact males and 11 were castrated; 4 animals were euthanased upon presentation, 7 were treated medically and 23 surgically, including urethrotomy, bladder marsupialisation, tube cystostomy alone or combined with urethrotomy, urethrostomy or penile reefing. Necrosis of the distal penis was found in 4 animals and all were short-term non-survivors. Short-term survival for surgical cases was 65%, and 57% for medical cases. Incomplete urethral obstruction at admission and surgical treatment were associated with increased odds of short-term survival. Of 14 records available for long-term follow-up, 6 animals were alive and 8 were dead (median follow-up 4.5 years, median survival time 2.5 years). Recurrence of urethral obstruction was associated with long-term non-survival. CONCLUSIONS: Surgically treated New World camelids with incomplete urethral obstruction have the best odds of short-term survival and those with recurrence of urethral obstruction have a poor prognosis for long-term survival.

Environmental Salmonella in agricultural fair poultry exhibits in Colorado.

Salmonella enterica is a common zoonotic pathogen in humans. Transmission typically occurs through consumption of contaminated food products or contact with infected animals, including poultry or their environment. The objective of this study was to estimate the frequency of Salmonella contamination in the environment in poultry exhibits at agricultural fairs. Samples were collected from cages, feed, floors and tables in the exhibit and cultured for Salmonella. At least one environmental sample was positive for Salmonella in 10 of 11 fairs (91%), and Salmonella was isolated from 28 of 55 environmental samples (50.9%). Eleven different serotypes were detected. Results of this study demonstrate that environmental surfaces at agricultural fairs can be contaminated with Salmonella and could potentially serve as a route of transmission to bird owners and the general public. Poultry owners and the general public should be educated about the risks of Salmonella infection from the poultry exhibit environment. Agricultural fairs should consider instituting policies and practices to improve hygiene and mitigate the risk of zoonotic salmonellosis.

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.

Detection and control of a nosocomial outbreak caused by Salmonella newport at a large animal hospital.

BACKGROUND: Nosocomial salmonellosis is often assumed to occur because infection control and surveillance practices are inadequate, but published evidence is lacking to support the related contention that rigorous application of these practices can impact the severity of outbreaks. OBJECTIVE: Describe active surveillance, early recognition, and intensive mitigation efforts used in an effort to control an outbreak of nosocomial Salmonella enterica serotype Newport infections without hospital closure. ANIMALS: Large animals hospitalized at a referral hospital. METHODS: This prospective outbreak investigation was initiated when Salmonella Newport infections were detected among hospitalized animals by active surveillance. Data were analyzed to identify temporal and spatial patterns for epidemic spread of Salmonella in the hospital. Mitigation efforts were aggressively adjusted in response to surveillance data. Genetic relatedness of isolates was investigated by pulsed-field gel electrophoresis. RESULTS: Of 145 large animals sampled, 8 (5.6%) were infected with the Salmonella strain associated with this outbreak, and all but 1 shed Salmonella in the absence of or before the onset of disease. This strain was recovered from 14.2% (42/295) of environmental samples (ENV samples), indicating that widespread environmental contamination had occurred. Isolates of Salmonella Newport obtained from infected animals and the environment were genetically indistinguishable, confirming clonal dissemination. CONCLUSIONS AND CLINICAL IMPORTANCE: Active surveillance allowed early detection of nosocomial Salmonella transmission and hospital contamination. Use of aggressive interventions was followed by cessation of transmission. Active surveillance can allow earlier recognition and mitigation compared with programs by only sampling of clinically affected animals.

Selenium and vitamin E.

Deficiency of selenium and vitamin E has recently been identified as a major health concern of sheep producers in certain regions of the United States, and familiarity with published data on these nutrients seems to be of value to small ruminant practitioners. This article begins with a description of the biochemical roles and metabolism of selenium and vitamin E. A literature review follows in which the influence of these nutrients on the musculoskeletal, reproductive, and immune systems, as well as on flock productivity, is discussed. Methods for detection of deficiency and supplementation strategies are also described.

Virulence factors in Escherichia coli isolated from the blood of bacteremic neonatal calves.

Twenty-five Escherichia coli isolates from the blood of critically ill bacteremic calves sampled in two separate studies on a calf-rearing farm housing over 15,000 calves, in the San Joaquin Valley, California were studied. Isolates were characterized for O serogroups and for pathotypes as determined by the presence of specific virulence factors including heat-labile enterotoxin (LT), heat-stable enterotoxins a and b (STa, STb), verotoxins 1 and 2 (VT1, VT2), cytotoxic necrotizing factor (CNF), aerobactin, intimin Eae and P, F17 and CS31A fimbrial adhesins, and resistance to bactericidal effects of serum. These isolates constituted a heterogeneous group. However, isolates were mostly aerobactin positive and often resistant to the bactericidal effects of serum. Isolates of pathotypes O78 (n=6), O119:CS31a (n=3), and P positive but O non-typeable (n=3) were associated with a high mortality rate. The remaining isolates belonged to diverse pathotypes, often possessing the adhesins P, F17, CS31A and Eae but belonging to O serogroups other than O78 and O119, and were less frequently associated with mortality. Although no virulence factor common to all isolates was identified, the capacity to use iron by the presence of aerobactin which is important to the capture of iron was a predominant factor. Moreover, certain pathotypes appear to be associated with primary colisepticemia whereas other pathotypes may cause a bacteremia without necessarily leading to septicemia.

Diagnosis of enteric disease in small ruminants.

Diagnosis of gastrointestinal disease in small ruminants requires integration of information obtained in the signalment, history, physical or necropsy examination, and ancillary diagnostic tests. The purpose of this article is to provide the practitioner with a review of the clinical features of several common gastrointestinal diseases of sheep and goats. Rumen acidosis, enterotoxemia, gastrointestinal parasitism, neonatal diarrhea, and salmonellosis are discussed, and where appropriate, reviews of the pathophysiology, prevention, and control of these diseases are cited for further reading.

Brucellosis induced by RB51 vaccine in a pregnant heifer.

Brucellosis developed in a 14.5-month-old Gelbvieh heifer after the animal was vaccinated with the calfhood dose of strain RB51 Brucella abortus vaccine s.c. during the fourth month of its first pregnancy. The heifer experienced dystocia and was euthanatized during cesarean section because of a large uterine tear. The fetus was dead at delivery. Suppurative placentitis and fetal pneumonia were evident at necropsy. Brucella abortus strain RB51 was isolated from the placenta and the fetus' lung.

Treatment of sodium balance disorders. Water intoxication and salt toxicity.

Electrolyte disorders are commonly identified in food animal medicine. Some of these electrolyte disturbances require that the veterinarian be aware of the potential for causing harm during routine fluid therapy. Hyponatremia (water intoxication) and hypernatremia (salt toxicity) are two such disorders. Both create osmolar disturbances that effect changes in the brain's osmolar state. During fluid resuscitation it is possible to cause iatrogenic central nervous system damage in these cases. It is important to recognize those cases where sodium imbalance may complicate routine therapy, understand the underlying mechanisms for osmolar changes in the plasma and brain, and know the appropriate steps to take for safe correction of the sodium disturbance.

Treatment of hypernatremia in an acidotic neonatal calf.

A 7-day-old Jersey calf was evaluated because of diarrhea and pneumonia. The calf was hypernatremic, hypoproteinemic, and acidemic, and was treated initially with i.v. administration of fluids with sodium concentration (175 mEq/L) similar to the calf's serum sodium concentration. Sodium concentration of the administered fluids was gradually decreased over the following days, but the calf's serum sodium concentration decreased too rapidly, and the calf developed neurologic signs attributed to cerebral edema. Treatment with mannitol and i.v. administration of fluids with a higher concentration of sodium resulted in abatement of clinical signs. In calves, hypernatremia may develop over several days. Prescribing traditional isotonic or hypotonic fluids in such cases will be harmful, because during chronic hypernatremia, the brain's adaptive mechanisms involve accumulation of organic osmoles that may take several days to equilibrate across cell membranes, and cerebral edema may result. Administration of fluids containing sodium concentration approximately equal to the patient's measured serum sodium concentration is required to decrease serum sodium concentration more slowly than is possible with traditional isotonic fluids.

Detection of low serum immunoglobulin concentrations in clinically ill calves.

The sensitivity, specificity, and accuracy of classification of 4 tests for failure of passive transfer (FPT) were examined in clinically ill neonatal calves. Comparisons were made with serum IgG1 concentrations determined by radial immunodiffusion. Serum samples were obtained from 27 clinically ill calves < or = 21 days of age. The results of 4 commonly used assays, the sodium sulfite turbidity test, the zinc sulfate turbidity test, refractometry, and the serum gamma-glutamyl transferase (GGT) activity test, were compared with radial immunodiffusion determinations of serum IgG1 concentration. Serum GGT activity using a 50 IU/L threshold resulted in correct classification of the highest percentage of calves (93%) with regard to their passive transfer status. The sodium sulfite test with a 1+ end point and refractometry using a 5.5 g/dL end point resulted in correct classification of 85% of the calves studied. When using the sodium sulfite test, the 2+ and 3+ test end points had lower specificity, 0.58 and 0.00, respectively, than the 1+ end point. This loss in specificity resulted in misclassification of calves with adequate serum immunoglobulin concentrations as having FPT. The zinc sulfate turbidity test was inadequately specific (0.33) and resulted in misclassification of 33% of calves.

Miniature pigs.

Miniature pigs have become popular pets in North America, and veterinarians of a variety of clinical specialties may be called on for their care. Successful collection of blood from these animals requires familiarity with the location of sites for venipuncture and knowledge of adequate methods of restraint. In this article, restraint and techniques for venipuncture are described, as well as techniques for cerebrospinal fluid collection, semen collection, and vaginal cytologic examination. Interpretation of hematologic, serum biochemical, and urinalysis data are also discussed. Methods for diagnosis of skin diseases, gastrointestinal parasitism, and enteric infectious diseases are included in order to provide the practitioner with the essential knowledge and skills for a variety of clinical pathologic studies of this unique pet.

Allergic respiratory disease.

Allergic rhinitis and extrinsic allergic alveolitis are the most common allergic disorders of the bovine respiratory system. Environmental and management factors play significant roles in the pathogenesis of these disorders. When compared to infectious or toxic respiratory disease, allergic respiratory disease is relatively rare and of far less economic importance in North American cattle; however, the environmental and management conditions conducive to these diseases exist in many regions. Therefore, familiarity with the clinical and epidemiologic features of these unique diseases will aid the veterinarian in establishing an accurate diagnosis. Signs of respiratory dysfunction are common to anaphylactic and anaphylactoid reactions. Early recognition of these adverse reactions will provide the practitioner with the greatest chance of successful treatment.

Bacteriological culture of blood from critically ill neonatal calves.

The objectives of this study were to estimate the prevalence of bacteremia in critically ill, neonatal calves with severe diarrhea or depression, and to describe the variety of bacteria involved. Two studies were conducted in the summers of 1991 and 1993 involving 190 neonatal calves, 1-day to 19-days-old. Bacteremia was detected by blood culture in 31% (28/90) of calves in study 1, and in 24% (19/79) of ill calves and 0% (0/21) of control calves in study 2. Bacteria cultured from blood included Escherichia coli (51% of all isolates), other gram-negative enterics (25.5%), gram-negative anaerobes (5.9%), gram-positive cocci (11.8%), and gram-positive rods (5.9%). Among clinically ill calves, the average age was significantly lower in the blood culture-negative group (5.5 d) than in the blood culture-positive group (7.5 d) (P = 0.004). Mean serum IgG concentration was significantly (P = 0.0001) lower in blood culture-positive calves (1.146 g/L) than in blood culture-negative calves (3.077 g/L). The mortality rate was significantly (P < 0.0001) higher in the blood culture-positive group (57.4%) than in the blood culture-negative group (15.1%). Bacteremia appeared to be a frequent entity in this particular rearing situation. Early recognition of the problem, as well as appropriate treatment, may be beneficial in increasing survival rates. Results also support the need to address the failure of passive transfer of maternal antibodies to prevent bacteremia in calves.

Use of a clinical sepsis score for predicting bacteremia in neonatal dairy calves on a calf rearing farm.

In human, equine, and bovine neonates, early diagnosis of bacteremia remains a challenge for the internist. The objective of this study was to develop a predictive model for risk of bacteremia, based on a clinical evaluation system called the clinical sepsis score. Blood from 90 ill calves, 1- to 14-days-old from a calf-raising farm in the San Joaquin Valley of California was cultured. The calves were also scored according to a clinical score for hydration status, fecal appearance, general attitude, appearance of scleral vessels, and umbilical abnormality. Age, rectal temperature, heart rate, respiratory rate, and presence or absence of a focal site of infection were recorded. Prevalence of bacteremia was 31% (28/90). A logistic regression model indicated that high clinical score, presence of a focal infection, and increased age were associated with an increased risk of bacteremia in ill calves (P < 0.06). Calves for which the model predicted bacteremia with a probability > or = 40.8% were considered bacteremic, yielding acceptable sensitivity (75%) and specificity (71%) estimates. The predictive model was validated through a 2nd sampling of 100 calves (79 ill calves and 21 controls), of which 17 calves were bacteremic. The classification was 75% correct using the model, with an estimated sensitivity of 76% and specificity of 75%. Overall, results indicated that the model could be a useful tool for predicting bacteremia in ill calves in a clinical setting.