Antimicrobial prophylaxis in companion animal surgery: A scoping review for European Network for Optimization of Antimicrobial Therapy (ENOVAT) guidelines

Surgical antimicrobial prophylaxis (SAP) is widely used to reduce the risk of surgical site infections (SSI), but there is uncertainty as to what the proportion of SSI reduction is. Therefore, it is difficult for surgeons to properly weigh the costs, risks and benefits for individual patients when deciding on the use of SAP, making it challenging to promote antimicrobial stewardship in primary practice settings. The objective of this study was to map the veterinary evidence focused on assessing the effect of SAP on SSI development and in order to identify surgical procedures with some research evidence and possible knowledge gaps. In October 2021 and December 2022, Scopus, CAB Abstracts, Web of Science Core Collection, Embase and MEDLINE were systematically searched. Double blinded screening of records was performed to identify studies in companion animals that reported on the use of SAP and SSI rates. Comparative data were available from 34 out of 39123 records screened including: eight randomised controlled trials (RCT), 23 cohort studies (seven prospective and 16 retrospective) and three retrospective case series representing 12476 dogs and cats in total. Extracted data described peri- or post-operative SAP in nine, and 25 studies, respectively. In the eight RCTs evaluating SAP in companion animals, surgical procedure coverage was skewed towards orthopaedic stifle surgeries in referral settings and there was large variation in SAP protocols, SSI definitions and follow-up periods. More standardized data collection and agreement of SSI definitions is needed to build stronger evidence for optimized patient care.

Variation in knowledge, attitude, and practices toward antibiotic use among diplomates of the American Veterinary Dental College: a survey-based study

OBJECTIVE

To evaluate the knowledge, attitudes, and practices toward antibiotic use among board-certified veterinary dentists.

SAMPLE

104 veterinarians board certified by the American Veterinary Dental College.

METHODS

A 30-question survey was generated from an online platform and sent via email listserv to board-certified veterinary dentists. Responses were examined to identify patterns or correlations among the variables of interest.

RESULTS

There were 104 board-certified veterinary dentists who responded. The majority reported using prophylactic intraoperative antibiotics sparingly for dental procedures and predominately for patients with historic endocarditis or on immunosuppressive doses of steroids. For healthy patients, they reported that antibiotics are often prescribed during jaw fracture repair, maxillectomy/mandibulectomy, and treatment of stage 4 periodontal disease or periapical lucencies. Knowledge of antibiotic resistance and evidence-based antibiotic use were not significantly different between different practice sectors (academia vs private practice) or dependent on the duration of board certification. Dentists who did not believe antibiotics used postoperatively reduce local postoperative infection rates were less likely to prescribe injectable intraoperative antibiotics for the prevention of postoperative infection. No other variables were associated with the likelihood of prescribing intraoperative antibiotics. More than 95% of veterinary dentists surveyed agreed that specific antibiotic use guidelines for veterinary dentistry would help reduce inappropriate use of antibiotics.

CLINICAL RELEVANCE

There are differences among veterinary dentists regarding which procedures and patient-specific comorbidities they believe necessitate the use of prophylactic antibiotics. The development of a consensus statement and prospective studies of current antibiotic use are important next steps to improving antibiotic stewardship in veterinary dentistry.

Removing prophylactic antibiotics from pig feed: how does it affect their performance and health?

BACKGROUND

Antibiotics (AB) are an important tool to tackle infectious disease in pig farms; however some research indicates that their frequent mis/over-use may contribute to the development of antibiotic resistance and the WHO has declared that this issue should be addressed. Little is known about the long term consequences of withdrawing prophylactic AB from pig feed; hence we aimed to assess its effects on performance and health of pigs from weaning to slaughter. Six batches of 140 pigs each were monitored on a commercial farm through the weaner and finisher stages to slaughter. In-feed antibiotics were not added to the feed for half of the pigs (NOI) and were added in the other half (ABI) within each batch for the whole weaner stage. Individual pigs in both treatments were treated with parenteral administrations if and when detected as ill or lame. Productive performance, parenteral treatments and mortality were recorded on farm and the presence of respiratory disease was recorded at slaughter. Pen was considered the experimental unit.

RESULTS

ABI pigs showed higher growth (P = 0.018) and feed intake (P = 0.048) than NOI pigs in the first weaner stage but feed efficiency was not affected (NOI = 1.48 vs. ABI = 1.52). Despite an initial reduction in performance, NOI pigs had similar performance in finisher stage (ADG: NOI = 865.4 vs. ABI = 882.2) and minimal effects on health compared to ABI pigs. No difference between treatments was found at the abattoir for the percentage of pigs affected by pneumonia, pleurisy, pleuropneumonia and abscesses (P > 0.05). Mortality rate was not affected by treatment during the weaner stage (P = 0.806) although it tended to be slightly higher in NOI than ABI pigs during the finisher stage (P = 0.099). Parenteral treatments were more frequent in NOI pigs during the weaner stage (P <  0.001) while no difference was recorded during the finisher stage (P = 0.406).

CONCLUSIONS

These data suggest that the removal of prophylactic in-feed antibiotics is possible with only minor reductions in productive performance and health which can be addressed by improved husbandry and use of parenteral antibiotics.

Biological Approaches for Disease Control in Aquaculture: Advantages, Limitations and Challenges

Although aquaculture activity has experienced a great development over the past three decades, infectious diseases have become a limiting factor for further intensification. Because the use of antibiotics has led to the widespread emergence of antibiotic resistance, the search for alternative environmentally friendly approaches is urgently needed. This Opinion paper offers an update on the successes and challenges of biological approaches for bacterial disease prevention and control in aquaculture. Although most of these approaches are still in research and development stages, some of them have shown promising results in field trials. Therefore, a better understanding of the mechanisms of action of these approaches will help to maximise their beneficial properties.

Initial Management of Traumatic Wounds

When traumatic wounds are quickly and accurately treated, morbidity and costs can be significantly decreased. Several factors, such as time delay between injury and treatment, the degree of contamination, extension and depth of the wound, and the mechanism of injury, influence the treatment and prognosis and stress the importance of a patient-specific approach. Although all traumatic wounds are contaminated, antibiotic therapy is seldom required if correct wound management is installed.

Program of vaccination and antibiotic treatment to control polyserositis caused by Haemophilus parasuis under field conditions

The present study investigated the effects of vaccinating sows and piglets or piglets alone against Haemophilus parasuis on the prevalence of H. parasuis in nasal swabs, on the humoral and cellular immune responses, and on the production parameters of piglets at 3 Korean farms with a clinical history of polyserositis caused by H. parasuis. Piglets born to vaccinated or non-vaccinated sows were subdivided into 3 groups: vaccinated sows and vaccinated pigs (VS-VP), non-vaccinated sows and vaccinated pigs (NVS-VP), and non-vaccinated sows and non-vaccinated pigs (NVS-NVP). The proportion of piglets with positive nasal swabs was significantly lower (P < 0.05) in the vaccinated animals (VS-VP and NVS-VP groups) than in the non-vaccinated animals (NVS-NVP group) at 35 and 60 d of age at the 3 farms. The overall growth performance (from 7 to 60 d of age) of the vaccinated piglets was significantly better (P < 0.05) than that of the non-vaccinated piglets at the 3 farms. Piglets in the VS-VP group had significantly higher levels (P < 0.05) of H. parasuis-specific IgG antibodies, lymphocyte proliferation, and interferon-γ-secreting cells than piglets in the NVS-VP and NVS-NVP groups on days 1, 7, 21, 35, and 60 after birth at the 3 farms.

Faecal shedding of CTX-M-producing Escherichia coli in horses receiving broad-spectrum antimicrobial prophylaxis after hospital admission

The objective of this longitudinal study was to investigate the occurrence and genetic background of faecal Escherichia coli resistant to cefotaxime (CTX) in horses receiving broad-spectrum antimicrobial prophylaxis after admission to a veterinary teaching hospital. The ten horses enrolled in the study were treated with cefquinome either alone (n=4) or in combination with metronidazole (n=3) or other antimicrobial agents (n=3). CTX-resistant coliforms in faeces collected before, during and after treatment were quantified on selective MacConkey agar supplemented with CTX, and a colony isolated randomly from each positive sample was characterized by pulsed-field gel electrophoresis, and by PCR detection and sequencing of bla(TEM), bla(SHV), bla(CTX-M) and bla(CMY). All horses were negative for CTX-resistant coliforms at admission but became positive within the first three days of treatment. The average faecal densities of CTX-resistant coliforms increased significantly following antimicrobial prophylaxis (P<0.001). Genetic characterization of 29 faecal isolates revealed that this effect was due to proliferation of E. coli producing either CTX-M-1 (n=28) or CTX-M-14 (n=1). Five CTX-M-1 isolates produced additional β-lactamases (TEM-1, CMY-34 and the novel variant CMY-53). Shedding of CTX-M-producing E. coli appeared intermittent in four horses and persisted two weeks after antimicrobial treatments in five of six patients tested after discharge from hospital. Nosocomial transmission was suggested by finding five identical CTX-M-1-producing E. coli pulsotypes in multiple horses. The originality of the study lies in the unanticipated high frequency and genetic diversity of CTX-M-producing E. coli observed in the faecal flora of hospitalized patients receiving broad-spectrum antimicrobial prophylaxis.

Decreased mortality of weaned pigs with Streptococcus suis with the use of in-water potassium penicillin G

This study evaluated the efficacy of potassium penicillin G in drinking water of weaned pigs to reduce mortality and spread of infection caused by Streptococcus suis. A total of 896 18-day-old weaned pigs were randomly assigned to either treatment with potassium penicillin G in-water (Treated), or no treatment (Control). The outcomes analyzed were total mortality, mortality due to S. suis, and overall counts of S. suis colonies. The risk of mortality due to S. suis and total mortality were significantly increased in the Control group compared with Treated pigs (P < 0.05). Bacterial culture of posterior pharyngeal swabs indicated that Control pigs were significantly more likely to have ≥ 1000 colonies of S. suis per plate than were Treated pigs (P < 0.05). This study demonstrates that potassium penicillin G administered in drinking water is effective in reducing mortality associated with S. suis infection and reducing tonsillar carriage of S. suis.

Vascular access port implantation and serial blood sampling in a Gottingen minipig (Sus scrofa domestica) model of acute radiation injury

Threats of nuclear and other radiologic exposures have been increasing, but no countermeasure for acute radiation syndrome has been approved by regulatory authorities. Because of their similarity to humans in regard to physiology and anatomy, we are characterizing Gottingen minipigs as a model to aid the development of radiation countermeasures. Irradiated minipigs exhibit immunosuppression, severe thrombocytopenia, vascular leakage, and acute inflammation. These complications render serial acquisition of blood samples problematic. Vascular access ports (VAP) facilitate serial sampling, but their use often is complicated by infections and fibrin deposition. We demonstrate here the successful use of VAP for multiple blood samplings in irradiated minipigs. Device design and limited postoperative prophylactic antimicrobial therapy before irradiation were key to obtaining serial sampling, reducing swelling, and eliminating infection and skin necrosis at the implantation site. Modifications of previous protocols included the use of polydioxanone sutures instead of silk; eliminating chronic port access; single-use, sterile, antireflux prefilled syringes for flushing; strict aseptic weekly maintenance of the device, and acclimating animals to reduce stress. VAP remained functional in 19 of 20 irradiated animals for as long as 3 mo. The remaining VAP failed due to a small leak in the catheter, leading to clot formation. VAP-related sepsis occurred in 2 minipigs. Blood sampling did not cause detectable stress in nonanesthetized sham-irradiated animals, according to leukograms and clinical signs.

Diseases in neonatal foals. Part 1: the 30 day incidence of disease and the effect of prophylactic antimicrobial drug treatment during the first three days post partum

REASONS FOR PERFORMING STUDY

Neonatal diseases have been grouped and analysed but up-to-date statistically significant information about the incidence and prevalence of diseases in foals is limited. Since the 1950s it has been a common management practice to administer a 3 day course of antimicrobial drugs to neonatal foals. This was shown to significantly reduce the incidence of infections (Platt 1977). Since then management practices have improved and it is widely believed that prophylactic antimicrobial drugs are no longer necessary in foal rearing.

OBJECTIVES

To determine the 30 day incidences or prevalences (depending on case definition) of various diseases and conditions in the neonatal foal and ascertain the influence of a prophylactic 3 day treatment on the frequency of infections.

METHODS

The population consisted of Thoroughbred foals born on stud farms in the Newmarket (UK) area in 2005 (n = 1031). Depending on the stud farm's practice in the use of prophylactic antimicrobial drugs, 2 groups of newborn foals (treated and untreated) were identified and followed for 30 days.

RESULTS

The 30 day incidences of infectious diseases under study were between 0.2% (osteomyelitis) and 5.85% (systemic disease with diarrhoea). The overall incidence for 'total infectious diseases' was 8.27%. The most commonly observed noninfectious condition was limb deformities (12.11% of all foals). There was no significant difference in the incidence of infectious diseases between the 2 groups.

CONCLUSION

Infectious diseases are still an important problem in neonatal foals requiring further investigation as to which factors other than antimicrobial prophylaxis are relevant for disease prevention.

POTENTIAL RELEVANCE

The results provide an up-to-date overview about the frequencies of various neonatal foal diseases. They do not support the traditional prophylactic use of antimicrobials to prevent infectious diseases in healthy newborn foals. However, it should be noted that this study was not a randomised controlled trial and therefore does not provide the strongest possible evidence for this conclusion.

Retrospective study of perioperative antimicrobial use practices in horses undergoing elective arthroscopic surgery at a veterinary teaching hospital

Perioperative antimicrobial administration practices were evaluated retrospectively in 97 horses undergoing elective arthroscopy, and antimicrobial use was compared with standard recommendations for perioperative prophylaxis. Parenteral antimicrobials were administered perioperatively to 95/97 (98%) horses, 88 of which received intravenous sodium penicillin. Time from 1st dose until 1st incision ranged from 30 to 390 min [142 +/- 55.6 min, mean +/- standard deviation (s), median 135 min], and the first incision was performed greater than 2 half-lives after administration of sodium penicillin in 86/95 (91%) cases. Overall duration of therapy was 30.8 +/- 24.2 h (mean +/- s). Six (6.3%) horses received only a single preoperative dose, while 63 (66%) horses were treated for 24 h or less. While objective data regarding optimal perioperative antimicrobial prophylaxis are limited, the antimicrobial use practices observed here commonly deviated from standard recommendations for perioperative prophylaxis.

Principles of antimicrobial therapy: what should we be using?

Although the use of antimicrobials has had an insurmountable impact on preventing patient morbidity and mortality, problems with antimicrobial resistance and antimicrobial-induced diarrhea are becoming more apparent in human and veterinary medicine. The mortality associated with nosocomial infection with antimicrobial-resistant bacteria in human patients is alarming. Similarly, in veterinary medicine, the morbidity and high cost of treatment of patients with postoperative infection, for example, are concerns. Specifically in equine medicine, the high morbidity and mortality associated with antimicrobial-induced diarrhea have been devastating in many equine practices. Misuse of antimicrobials is extremely common in human and veterinary medicine. All clinicians have the responsibility to consider the appropriateness of their antimicrobial use carefully and, whenever possible, to minimize antimicrobial administration to patients.

[Antimicrobial resistance of Escherichia coli isolated from pigs in Argentina]

Antimicrobial resistance of Escherichia coil isolated from pigs in Argentina. Sixty-nine Escherichia coli isolates from healthy pigs or with clinical signs non-compatible with diarrhea caused by this microorganism, were studied. The purpose was to determine the resistance profile against antimicrobials frequently used in veterinary and human medicine. The agar diffusion method was used. High resistance percentages against antimicrobials used in swine farms such as ampicillin, streptomycin and tetracycline were observed, as well as against trimetoprim-sulfametoxazole and chloramphenicol, compounds that were stopped being used several years ago. Sixty two percent of isolates showed multidrug-resistance. The results obtained in this work corroborate the hypothesis that the phenotypic distribution of resistance and possibly that of its genetic determinants, are directly influenced by the antimicrobial treatments used.

A retrospective study of pathologic findings in the Amazon and Orinoco river dolphin (Inia geoffrensis) in captivity

River dolphins are especially susceptible to negative human impacts. For their conservation, attempts of relocation or procreation ex situ may become important in the future to avoid their extinction. Additional knowledge and medical experiences of river dolphin management in captivity may aid such conservation efforts. The medical records and necropsy and histopathology reports on 123 captive Amazon River dolphins (Inia geoffrensis) were re-viewed. Of these 123 animals, 105 were necropsied and 70 necropsies were supported with histopathology. Eighteen animals were not necropsied. Among wild-born animals, mortality was highest in the first 2 mo immediately postcapture and transport, accounting for 32 of 123 deaths. Pneumonia and skin lesions (cutaneous and subcutaneous ulcerations and abscesses) were the most common findings, found in 44 of 105 (42%) and 38 of 105 (36%) of gross diagnoses, respectively. At least 10 of 44 cases of pneumonia diagnosed grossly included a verminous component. Cachexia, from a variety of causes, was a major gross finding in 21 animals. Fifteen animals had histologic evidence of significant renal pathology, and this was the primary cause of death in 13 cases. Hepatic pathology was found in 18 cases, and bacterial sepsis was confirmed via histology in 16 cases. Based on these findings, it may be concluded that keys to successful maintenance of this species include 1) prophylactic anthelminthic and antibiotic therapy immediately post-capture; 2) maintenance of animals in larger enclosures than in past attempts, in compatible groups, and in facilities capable of separating aggressive animals; 3) maintenance in microbiologically hygienic water quality at all times; and 4) a proactive program of preventive medicine during the immediate postcapture, quarantine, and maintenance period of captivity.

Antimicrobial use in the surgical patient

Antimicrobials are often used in the surgical patient in an effort to prevent infection (prophylactic) or to treat established infection (therapeutic). To be effective, prophylactic antimicrobials at appropriate concentrations must be present in tissues at the surgical site at the time of contamination to prevent bacterial growth and subsequent infection. Therapeutic antimicrobials are used to treat established localized or systemic infection. Selection of antimicrobial agents for prophylactic or therapeutic use should be based on knowledge of expected flora, ability of the antimicrobial to reach the target tissue at appropriate concentrations, bacterial resistance patterns, drug pharmacokinetics, and culture and susceptibility testing results (therapeutic use). Failure of antimicrobial therapy to prevent or treat infection in the surgical patient may result from poor antimicrobial selection, inappropriate dosage or frequency, or inappropriate duration of therapy.

Challenges to Military Working Dog Management and Care in the Kuwait Theater of Operation

In a combat environment, troop safety and installation security are paramount. Documentation of the frequent use of explosive devices by insurgents in Southwest Asia has increased the need for augmentation of defensive capabilities. Military working dogs (MWDs) are trained and certified to perform missions supporting security and detection of explosives. Challenges arise in theater because the number of certified dogs available can be limited and the standards of housing and care that are available in the continental United States are not usually available in a combat theater. Planning, preparation, and training of MWD handlers,animal care specialists, and Veterinary Corps officers will maximize mission performance and MWD health. Some of th echallenges and needs associated with management and care of the MWDs in the Kuwait theater of operation are discussed. Suggested improvements to the current deployment readiness paradigm are offered from the perspective of a staff veterinarian who was deployed in support of Operation Iraqi Freedom in 2004.

Prevention of Postoperative Infections in Horses

The best defense against postoperative infection is to use multiple strategies to minimize wound contamination, maintain wound tissue health, and provide rational antimicrobial strategies that do not promote the development of resistant bacteria and superinfections.

Perioperative administration of antimicrobials associated with elective surgery for cranial cruciate ligament rupture in dogs: 83 cases (2003–2005)

OBJECTIVE

To evaluate perioperative antimicrobial use associated with elective surgery for cranial cruciate ligament rupture in dogs.

DESIGN

Retrospective case series.

ANIMALS

83 dogs.

PROCEDURES

Medical records were reviewed and antimicrobial use practices were evaluated for dogs with no other problems that would affect antimicrobial use decisions.

RESULTS

Antimicrobials were administered before or during surgery to 75 of 83 (90%) dogs. Timing of administration with respect to first incision, intraoperative administration, and duration of administration were variable. Antimicrobial administration began after surgery in 3 (3.6%) dogs. Fifty-five of 65 (85%) dogs treated before surgery received the first dose within 60 minutes of the first incision. Time from first antimicrobial administration to closure of the incision ranged from 15 to 285 minutes (mean +/- SD, 141 +/- 53 minutes). If a guideline of repeated administration every 2 hours after first administration until closure of the surgical site was used, 22 of 43 (51%) dogs received the required intraoperative dose, whereas 6 of 32 (19%) dogs that did not require intraoperative treatment were treated. Twenty-four (29%) dogs received antimicrobials after surgery.

CONCLUSIONS AND CLINICAL RELEVANCE

Certain discrepancies between antimicrobial use practices in this study and standard guidelines used in human medicine were evident.

A Clinical Trial Evaluating Prophylactic and Therapeutic Antibiotic Use on Health and Performance of Preweaned Calves

The objective of this clinical trial was to evaluate the influence of prophylactic and therapeutic antibiotics on health and performance in preweaned dairy calves on a calf ranch. One hundred twenty 1-d-old calves were enrolled into 3 management systems for antibiotic use and raised until 4 wk of age. Sixty calves were not eligible to receive prophylactic or therapeutic antibiotics. Thirty calves were eligible to receive individual antibiotic treatment for disease, but no prophylactic antibiotics in milk replacer. The remaining 30 calves received milk replacer medicated with neomycin and tetracycline HCl, and could be treated with antibiotics. Health status and treatments were monitored and recorded daily. The primary study outcomes were weight gain, morbidity, and mortality. The most important factor associated with morbidity and mortality was passive immune transfer through colostrum. In-feed antibiotics delayed onset of morbidity, decreased overall morbidity, and increased weight gain. Nonantibiotic therapies for clinical disease were associated with increased mortality and morbidity compared with antibiotic treatments. The study has shown that minimizing or eliminating the use of antibiotics in the feed requires measures to ensure adequate passive transfer of immunity, but that in the face of inadequate passive transfer of immunity, animal welfare may be endangered by replacing medicated milk replacer with nonmedicated milk replacer, and therapeutic antibiotics with nonantibiotic alternatives.

Susceptibility ofClostridium perfringensstrains from broiler chickens to antibiotics and anticoccidials

Clostridium perfringens strains isolated in 2002 from the intestines of broiler chickens from 31 different farms located in Belgium were tested for susceptibility to 12 antibiotics used for therapy, growth promotion or prevention of coccidiosis. All strains were uniformly sensitive to the ionophore antibiotics monensin, lasalocid, salinomycin, maduramycin and narasin. All were sensitive to avilamycin, tylosin and amoxicillin, while flavomycin (bambermycin) showed low or no activity. Chlortetracycline and oxytetracycline were active at very low concentrations, but low-level acquired resistance was detected in 66% of the strains investigated. Fifty percent of these strains carried the tetP(B) resistance gene, while the tet(Q) gene was detected in only one strain. One strain with high-level resistance against tetracyclines carried the tet(M) gene. Sixty-three percent of the strains showed low-level resistance to lincomycin. The lnu(A) and lnu(B) genes were each only found in one strain. Compared with a similar investigation carried out in 1980, an increase was seen in resistance percentages with lincomycin (63% against 49%) and a slight decrease with tetracycline (66% against 74%).

Treatment of periodontal pockets with doxycycline in beagles

Following pretreatment with clindamycin, cleaning, scaling, polishing, and curettage, six beagles that were patients at the Dental Department of the Clinic for Surgery and Ophthalmology of the University of Veterinary Medicine of Vienna received a doxycycline polymer filling (Doxirobe, Pharmacia Animal Health) in periodontal pockets of teeth 204, 208, 304, and 309. Gingivitis index, gingival crevicular fluid, probing depth, and attachment loss were determined before and 6 and 12 weeks after treatment. Teeth 104, 108, 404, and 409 did not receive antibiotic therapy but were pretreated in the same manner as the doxycycline-treated teeth. Pocket depth for teeth treated with doxycycline was significantly reduced (improved) by 39% after 6 weeks (P =.001) and by 35% after 12 weeks (P =.001). Pockets around control teeth were improved after cleaning and curettage but were still significantly deeper than around teeth treated with doxycycline. Compared with control teeth, teeth treated with doxycycline had significantly less gingival crevicular fluid after treatment (P =.001). Teeth treated with doxycycline gained significant attachment after 6 (42%) and 12 (38%) weeks. Significantly fewer bacteria were harvested from doxycycline-treated teeth than from control teeth. The gingival index was significantly lower in the doxycycline-treated teeth than in the control teeth 6 (P =.002) and 12 (P =.007) weeks after treatment. Local application of doxycycline complements traditional subgingival curettage therapy in a reasonable and effective way and can significantly improve treatment success, especially with regard to pocket depth reduction and attachment gain.

Differences in antibiotic resistance in Escherichia coli, isolated from East-European swine herds with or without prophylactic use of antibiotics

The aim of the study was to compare the resistance patterns of Escherichia coli isolates from pig herds with or without prophylactic use of anti-microbial substances. The presented pig units received either antibiotics or oregano as preventive feed additives. The trial was performed from April to October 2001, in the large 'country-corner', Hungary-Rumania-Serbia. Thirty of 39 evaluated herds suffered E. coli O139 K88 ac or ad LT STb caused losses, the remaining were negative for E. coli O139. Thirteen of the selected 30 herds produced with oregano feed supplementation (Oregpig Pecs, Hungary) antibiotic-free pigs. These units had no history of prophylactic antibiotic use since 1995. The remaining 17 herds routinely used prophylactic antibiotic feed supplementation. In each herd, pigs of four different age groups (suckling piglets, weaners. fattening swine and breeding sows), showing the clinical symptoms of wasting, were investigated. E. coli O139 K88 ac or ad LT STb were tested for their resistance to antibiotics, available in this region. Oregano-fed herds demonstrated high significantly (P < 0.001) lower MICs (microg/ml) for ampicillin, doxycyclin, enrofloxacin, gentamycin, oxytetracyclin and sulfamethacin compared to herds with prophylactic use of antibiotics. Resistance to ceftiofur revealed significant (P < 0.05) differences between the antibiotic- or oregano-treated units. The present results confirm literature data, that prophylactic use of antibiotics likely plays a role in inducing resistance of E. coli and other intestinal bacteria. Thus, imposing greater restrictions on antibiotic use in animal agriculture is likely to reduce but not eliminate the occurrence of resistant isolates.

Survey of complications and antimicrobial use in equine patients at veterinary teaching hospitals that underwent surgery because of colic

OBJECTIVE

To determine current practices regarding use of antimicrobials in equine patients undergoing surgery because of colic at veterinary teaching hospitals.

DESIGN

Survey.

SAMPLE POPULATION

Diplomates of the American College of Veterinary Surgeons performing equine surgery at veterinary teaching hospitals in the United States.

PROCEDURE

A Web-based questionnaire was developed, and 85 surgeons were asked to participate. The first part of the survey requested demographic information and information about total number of colic surgeries performed at the hospital, number of colic surgeries performed by the respondent, and whether the hospital had written guidelines for antimicrobial drug use. The second part pertained to nosocomial infections. The third part provided several case scenarios and asked respondents whether they would use antimicrobial drugs in these instances.

RESULTS

Thirty-four (40%) surgeons responded to the questionnaire. Respondents indicated that most equine patients undergoing surgery because of colic at veterinary teaching hospitals in the United States received antimicrobial drugs. Drugs that were used were similar for the various hospitals that were represented, and for the most part, the drugs that were used were fairly uniform irrespective of the type of colic, whereas the duration of treatment varied with the type of colic and the surgical findings. The combination of potassium penicillin and gentamicin was the most commonly used treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of this study document the implementation of recommendations by several authors in veterinary texts that antimicrobial drugs be administered perioperatively in equine patients with colic that are undergoing surgery. However, the need for long-term antimicrobial drug treatment in equine patients with colic is unknown.

Positive intraoperative cultures and canine total hip replacement: risk factors, periprosthetic infection, and surgical success

The results of closing intraoperative cultures from 27 canine total hip replacements (THR) were reviewed. The relationship between these culture results and presurgical and surgical factors, and the short- and long-term success of THR were assessed. Eleven out of 27 cases had a positive culture, but none of these 11 cases were diagnosed with periprosthetic infection at follow-up examination. The duration of the clinical signs of hip disease prior to THR was significantly greater for those cases with a positive culture (P=0.034). The incidence of positive cultures was not related to surgical success.

Effects of rearing conditions on the colonization of Salmonella enteritidis in the cecum of chicks

Salmonella enteritidis is the cause of human salmonellosis associated with contaminated eggs. In this study, we artificially challenged S. enteritidis to chicks just after hatching, and the effects of breeding conditions on the intestinal carriage of S. enteritidis were examined. S. enteritidis was not directly detected from spleen, liver and blood, but were constantly isolated from the cecal contents throughout the experiment. When chicks were reared in the unsanitary conditions and in the high housing density, the numbers of S. enteritidis increased. The subsequent experiment was undertaken to examine whether the antibacterial additive in a feed would have any impact on S. enteritidis colonization in chicks. Some antibiotic effective on the growth promotion had an influence on S. enteritidis colonization.

Effect of enrofloxacin-Na against pathogens related to the respiratory and alimentary diseases in suckling and weanling piglets

A field trial was conducted to evaluate effect of enrofloxacin-Na against pathogens related to the respiratory and alimentary diseases in eighty suckling piglets (6-7 days old) and eighty weanling piglets (5-6 weeks old). Respective twenty of the suckling and weanling piglets were assigned to each of 4 experimental groups; control (non-treated), clinical injection dose (CID), 2x clinical injection dose (2CID). and premix. A 0.05 ml (2.5 mg) of enrofloxacin-Na injection (5% solution, 1 ml) per kg body weight of piglets as CID was injected intramuscularly for 3 days and the clinical signs were observed for 9 days. The premix (150 ppm) of enrofloxacin-Na was administered with feed for 7 days ad libitum and the clinical signs were observed for 13 days. The enrofloxacin-Na-treated piglets showed a higher increase in body weight and a lower feed per gain than the control piglets. In addition, the treatment of enrofloxacin-Na, regardless of the route of administration, decreased the incidence rate of diarrhea in suckling piglets and respiratory symptoms in weanling piglets. The isolation index of E. coli and Cl. perfringens during the treatment periods was also lowered by the enrofloxacin-Na treatment in both suckling and weanling piglets. The antibiotics was also evaluated as safe locally and whole bodily as treated by injection or feeding. These results indicate that the newly developed antibiotics, enrofloxacin-Na, is very useful for the prevention and therapy of swine diseases in the pig industry.

Influence of ileo-caecal cannulation and oxytetracycline on ileo-caecal and rectal coliform populations in pigs

The effect of surgery (insertion of an ileo-caecal cannula) and a subsequent parenteral treatment with oxytetracycline on the ileo-caecal and rectal coliform populations in 7 Swedish Yorkshire castrates were studied. Samples were collected during surgery as well as 3, 7, 14 and 20 days post surgery. The diversity of the enteric coliform flora was initially high both in the ileo-caecal ostium and in rectum. No alteration in the diversity of the enteric coliform flora was observed following surgery and treatment with oxytetracycline. As the insertion of ileo-caecal cannulas did not affect the intestinal coliform flora this study gives support to the use of this technique to mirror processes in the small intestine of pigs. Further, the diversity of the enteric coliform flora was unaffected by the parenteral treatment with oxytetracycline.

Antimicrobial residue detection in chicken yolk samples following administration to egg-producing chickens and effects of residue detection on competitive exclusion culture (PREEMPT) establishment

Competitive exclusion (CE) cultures may offer alternatives to antimicrobial agents for disease prophylaxis in poultry. To avoid potential transfer of antibiotic resistance, safe and effective CE cultures must, by necessity, be highly sensitive to antimicrobial residues. The following studies evaluated the effect of maternal administration of selected antibiotics on the establishment of a licensed CE culture, PREEMPT. Selected antibiotics were administered to actively laying hens for a period of 7 days (experiment 1) or 9 days (experiment 2) in drinking water [sulfadimethoxine (0.05%), enrofloxacin (0.005%), and tylosin tartrate (0.05%)] or feed (sulfadimethoxine with ormetoprim, 250 ppm). In experiment 1, fertile eggs were collected daily and subjected to bioassay for detectable antimicrobial residues in yolk. Antimicrobial residues were not detected during the 7 days of treatment or the subsequent 3 days following cessation of treatment in the control, sulfadimethoxine, sulfadimethoxine with ormetoprim, or tylosin treatment groups. However, detectable residues were observed in eggs derived from enrofloxacin-treated hens on days 6 and 7 during antibiotic administration and also on days 2 and 3 post-antibiotic administration. In experiment 2, antimicrobial residues were also only detected in yolks from hens treated with enrofloxacin. Residue detection occurred on days 2-6 of antibiotic administration, on day 9 of antibiotic administration, on days 1-3 post-antibiotic administration, and also on day 7 post-antibiotic administration. A subset of eggs from each experimental group, corresponding to days 2-6 of antibiotic administration, days 4-6 post-antibiotic administration, and days 14-16 post-antibiotic administration, were pooled for incubation, and chicks hatched from these pools of fertile eggs were treated with PREEMPT at hatch. When 48-h cecal propionate concentrations were used as an index of culture establishment, reduced (P < 0.05) efficacy was observed only in chicks derived from enrofloxacin-treated hens at either collection period. Although several antibiotics do not appear to produce detectable egg residues or interfere with CE culture establishment, these data suggest that chicks derived from enrofloxacin-treated hens may not be candidates for safe and effective CE culture treatment.

Effects of tilmicosin phosphate, administered prior to transport or at time of arrival, and feeding of chlortetracycline, after arrival in a feedlot, on Mannheimia haemolytica in nasal secretions of transported steers

OBJECTIVE

To determine effects of time of administration of tilmicosin and feeding of chlortetracycline on colonization of the nasopharynx of transported cattle by Mannheimia haemolytica (MH).

ANIMALS

454 steers (body weight, 200 kg).

PROCEDURE

3 studies included 4 truckloads of steers assembled and processed in the southeastern United States. For each truckload of steers, a third received tilmicosin before transportation (PRIOR), then all were transported to a feedlot in New Mexico (23 hours). At arrival (day 0), another third received tilmicosin (ARR). The remaining third did not receive tilmicosin (control steers [CTR]). Steers in studies 1 and 2 were housed in a feedlot, and steers in study 3 were housed on wheat pasture. One half of the steers from each group in studies 2 and 3 were fed chlortetracycline on days 5 to 9. Steer with signs of respiratory tract disease were treated. Nasal swab specimens were examined for MH to determine colonization.

RESULTS

PRIOR and ARR steers had a lower incidence of respiratory tract disease and MH colonization than CTR steers, but PRIOR and ARR steers did not differ. Feeding chlortetracycline did not have an effect.

CONCLUSIONS AND CLINICAL RELEVANCE

Tilmicosin can inhibit MH from colonizing the nasopharynx of cattle. Because tilmicosin inhibits the growth of MH in the respiratory tract, medication with tilmicosin prior to transport should reduce the incidence of acute respiratory tract disease during the first week at the feedlot when calves are most susceptible to infectious organisms.

Calibration for nonlinear mixed effects models: an application to the withdrawal time prediction

We propose calibration methods for nonlinear mixed effects models. Using an estimator whose asymptotic properties are known, four different statistics are used to perform the calibration. Simulations are carried out to compare the performance of these statistics. Finally, the milk discard time prediction of an antibiotic, which has motivated this study, is performed on real data.

Development of a rapid and inexpensive assay for the nonspecific detection of antimicrobial residues in chicken egg yolks and neonatal yolk sacs

Competitive exclusion of intestinal pathogens by administration of beneficial and defined cultures of normal intestinal microflora is a safe and effective means of reducing the incidence and severity of chick infections with Salmonella and other intestinal pathogens. It is important that competitive exclusion cultures not carry genetic material (e.g., plasmids), which could transfer antibiotic resistance to other microflora, including pathogens. As such, safe and effective competitive exclusion cultures must be sensitive to commonly used antimicrobial agents. By necessity, intentional or accidental exposure of these beneficial microflora to antibiotics will reduce or eliminate the protection provided by competitive exclusion culture establishment. As antibiotic residues can be present from embryonic, hatchling, or maternal administration, a rapid and sensitive assay for the nonspecific detection of residues, which could interfere with competitive exclusion culture establishment, is needed. This study was conducted to develop a rapid and inexpensive bioassay to detect multiple antimicrobial residues in egg yolk and neonatal yolk sacs. Aerobic bacterial strains with known sensitivity to several antibiotics used by the poultry industry were selected and individually compared for sensitivity to enrofloxacin, gentamicin, tetracycline, ceftiofur, and tylosin concentrations in egg yolks. This assay was found to be relatively sensitive for the detection of these antimicrobials, and detection of residues was associated with reduced competitive exclusion culture (PREEMPT) establishment in one experiment. Importantly, this assay can be implemented with minimal training or equipment under commercial hatchery practices and could be used to determine embryo groups, in advance of hatch, that are not suitable candidates for competitive exclusion treatment in the hatchery.

The effect of in ovo or day-of-hatch subcutaneous antibiotic administration on competitive exclusion culture (PREEMPT) establishment in neonatal chickens

The effect of in ovo or day-of-hatch subcutaneous antibiotic administration on the detection of antibiotic residues in yolk sac or blood serum samples and the potential for observed residues to interfere with competitive exclusion (CE) culture establishment was compared in three experiments. The in ovo or subcutaneous administration of gentamicin sulfate or ceftiofur sodium was associated with detectable levels of antibiotic residues in yolk sac or blood serum samples in Experiment 1. Further, the ability to detect antibiotic residues in day-of-hatch chicks was associated with reduced levels of CE culture establishment when cecal propionate level, an indicator of PREEMPT establishment, was determined following PREEMPT application by oral gavage on the day of hatch in Experiments 1 and 2. Restricting chicks from feed, as opposed to providing access ad libitum to a starter ration, for 6 h immediately following administration of PREEMPT improved (P < 0.05) CE culture establishment in Experiment 2 in nonantibiotic injected control chicks, but did not affect (P > 0.05) experimental groups receiving either gentamicin sulfate or ceftiofur sodium by either in ovo or subcutaneous routes. The in ovo administration of 0.1 or 0.2 mg ceftiofur sodium to individual embryos on Day 18 of embryogenesis in Experiment 3 was associated with marked depressions (P < 0.05) in cecal propionate levels compared with uninjected control chicks. When feed was restricted and the time of PREEMPT administration was delayed for 48 or 72 h posthatch, mean cecal propionate levels in in ovo ceftiofur sodium-injected chicks were not significantly different (P > 0.05) from controls, indicating a time- and feed restriction-associated effect on improving CE culture establishment.

Bacterial contamination of suction tips used during surgical procedures performed on dogs and cats

OBJECTIVE

To determine prevalence of bacterial contamination of surgical suction tips.

SAMPLE POPULATION

Surgical tips used during 44 surgical procedures performed on 42 dogs and 2 cats.

PROCEDURE

Surgical procedures were classified into 1 of 3 categories according to degree of bacterial contamination of the surgical site (clean, clean-contaminated, contaminated). Two sets of suction apparatuses were used for test and control suction tips. Test tips were used normally to suction blood and fluid, whereas control tips were placed on the surgical drapes but not in the surgical wound. Suction tips were collected aseptically and placed into thioglycolate broth tubes for qualitative aerobic and anaerobic bacterial culture at the end of each procedure.

RESULTS

Test and control suction tips were contaminated with bacteria during 30 of 44 (68%) procedures. Staphylococcus spp were the predominant bacteria in tips used during clean and clean-contaminated surgeries. When surgery was performed on clean-contaminated or contaminated wounds, prevalence of isolation of other bacteria such as Pseudomonas spp, Streptococcus spp, and Escherichia coli from both test and control suction tips was higher than for clean wounds. Mean time of procedures during which both test and control suction tips became contaminated was not significantly different from time of procedures during which neither tip became contaminated.

CONCLUSION AND CLINICAL RELEVANCE

Surgical suction tips often become contaminated during standard veterinary surgical procedures. The risk of wound infection after surgery may be influenced by bacterial contamination of surgical suction tips.

Efficacy of antimicrobial treatments and vaccination regimens for control of porcine reproductive and respiratory syndrome virus and Streptococcus suis coinfection of nursery pigs

Seventy-six, crossbred, porcine reproductive and respiratory syndrome virus (PRRSV)-free pigs were weaned at 12 days of age and randomly assigned to seven groups of 10 to 11 pigs each. Pigs in group 1 served as unchallenged controls. Pigs in groups 2 to 7 were challenged intranasally with 2 ml of high-virulence PRRSV isolate VR-2385 (10(4.47) 50% tissue culture infective doses per 2 ml) on day 0 of the study (30 days of age). Seven days after PRRSV challenge, pigs in groups 2 to 7 were challenged intranasally with 2 ml of Streptococcus suis serotype 2 (10(8.30) CFU/2 ml). Group 2 pigs served as untreated positive controls. Antimicrobial treatments included daily intramuscular injection with 66,000 IU of procaine penicillin G per kg of body weight on days 8 to 10 (group 3), drinking water medication with 23.1 mg of tiamulin per kg during days 8 to 10 (group 4), and daily intramuscular injection of 5.0 mg of ceftiofur hydrochloride per kg on days 8 to 10 (group 5). Vaccination regimens included two intramuscular doses of an autogenous killed S. suis vaccine (group 6) prior to S. suis challenge or a single 2-ml intramuscular dose of an attenuated live PRRSV vaccine (group 7) 2 weeks prior to PRRSV challenge. Mortality was 0, 63, 45, 54, 9, 40, and 81% in groups 1 to 7, respectively. Ceftiofur treatment was the only regimen that significantly (P < 0. 05) reduced mortality associated with PRRSV and S. suis coinfection. The other treatments and vaccinations were less effective. We conclude that ceftiofur administered by injection for three consecutive days following S. suis challenge was the most effective regimen for minimizing disease associated with PRRSV and S. suis coinfection.

Diagnostic and public health dilemma of lactose-fermenting Salmonella enterica serotype Typhimurium in cattle in the Northeastern United States

The presence of lactose-fermenting Salmonella strains in clinical case materials presented to microbiology laboratories presents problems in detection and identification. Failure to detect these strains also presents a public health problem. The laboratory methods used in detecting lactose-fermenting Salmonella enterica serotype Typhimurium from six outbreaks of salmonellosis in veal calves are described. Each outbreak was caused by a multiply-resistant and lactose-fermenting strain of S. enterica serotype Typhimurium. The use of Levine eosin-methylene blue agar in combination with screening of suspect colonies for C8 esterase enzyme and inoculation of colonies into sulfide-indole-motility medium for hydrogen sulfide production was particularly effective for their detection. A hypothesis for the creation of lactose-fermenting salmonellae in the environment is presented. It is proposed that the environment and husbandry practices of veal-raising barns provide a unique niche in which lactose-fermenting salmonellae may arise.

Effect of avilamycin, tylosin and ionophore anticoccidials on Clostridium perfringens enterotoxaemia in chickens

In order to study the prophylactic and metaphylactic effect of antomicrobial growth promoters and ionophorous anticoccidials on the incidence of Cl. perfringens enterotoxaemia in chickens, experimental attempts were performed with 675 chickens in 27 trials. The birds were intraduodenally infected with Cl. perfringens type A (ATCC 3624). The following antimicrobial growth promoters and ionophore anticoccidials were used either on their own or in combination: avilamycin, narasin, monensin and tylosin. While infected and non-medicated trials showed an average incubation period of 1 week, clinical symptoms occurred 2-4 days later in infected and medicated birds. Avilamycin medicated birds had the longest incubation period. In the infected and non-medicated trials, a mortality rate of 16%-36% was noted within 3 weeks post infection. The avilamycin trials showed a mortality rate of 0-8% (0-2 birds died) and the narasin and monensin a mortality rate of 0-8%, respectively. In the combination groups (monensin + avilamycin or narasin + avilamycin), the mortality rate ranged from 0 to 4%. Tylosin showed a very good metaphylactic/therapeutic effect against Cl. perfringens enterotoxaemia. Following infection, medicated birds showed a significantly better bodyweight gain than the chickens, whose feeds had not been supplemented. From epidemiological point of view, the systematic prevention of coccidiosis is a key in the control of Cl. perfringens enterotoxaemia in chickens.

Comparison of the supplemental effects of Saccharomyces cerevisiae and antibiotics in low-protein and high-fibre diets fed to broiler chickens

Two experiments were completed to compare the supplemental effects of yeast Saccharomyces cerevisiae and sub-therapeutic antibiotics in high-fibre and low-protein diets for broiler chicks. In experiment 1, yeast was added at 1.5, 3.0 and 6.0 g kg-1 while penicillin, tylosin or neoterramycin were added at 150 mg kg-1 into different batches of a high-fibre diet containing 250 g kg-1 palm kernel meal. Saccharomyces cerevisiae and antibiotics increased BW, BWG, FCR, feed intake, carcass and breast weights above the control. Small intestine weight was reduced by antibiotics, while yeast caused a lower deposition of abdominal fat. Liver weights of different treated broilers were similar. The performance indices were superior on penicillin and 3.0 g kg-1 yeast compared to other supplements evaluated. In the second experiment, 1.5 and 3.0 g kg-1 of yeast, and 0.75 mg kg-1 of procaine penicillin, zinc bacitracin and tylosin were separately added to a 180 g kg-1 crude protein diet. Performance of the chicks with additives was compared with unsupplemented negative and positive controls containing 180 and 210 g kg-1 crude protein respectively. Broilers fed with supplements had superior BW, BWG, FCR and feed intake compared to the negative control, but carcass data were similar. Dietary penicillin increased BW, BWG, feed intake more than other supplements, but yeast stimulated higher FCR. Data from both studies indicated that Saccharomyces cerevisiae comparatively increased growth and carcass weight and reduce abdominal fat, therefore, it can serve as a natural substitute for antibiotics in broiler diet.

Antibiotic treatment and post-handling survival of reindeer calves in Alaska

Free ranging reindeer (Rangifer tarandus tarandus) are driven into corral systems and handled each summer on the Seward Peninsula (Alaska, USA). During June and July of 1995-96 reindeer calves were inspected for injury, handled, weighed, and randomly treated with long-acting oxytetracycline. Calves that returned to subsequent handlings within the same year, received treatment only if they had been treated during their first handling. The effects of prophylactic antibiotic treatment and other factors, including weight, handling related injury, and sex on post-handling survival in reindeer calves were evaluated. Return rates of yearlings in 1996 and 1997 were analyzed using logistic regression. Weight change of calves between handlings was examined using a general linear model. Calf weight and handling injury were the only factors that significantly affected calf survival. No factor had a significant effect on calf weight change between handlings. Apparently, long-acting oxytetracycline was not an effective prophylactic treatment for this capture operation. The benefits of prophylactic antibiotic treatment have not been quantified and further studies of the effects and efficacy of prophylactic treatments are recommended. Ineffective treatments should be avoided because they may add additional stress to the captured animal. Managers should evaluate the potential effectiveness of a prophylactic treatment before indiscriminately applying one. Preventing calf injuries was the most effective method of reducing post-handling mortality in this study and should be given a high priority in the design of capture operations.

Drug disposition and dosage determination of once daily administration of gentamicin sulfate in horses after abdominal surgery

OBJECTIVE

To evaluate pharmacokinetics of once daily i.v. administration of gentamicin sulfate to adult horses that had abdominal surgery.

DESIGN

Prospective study.

ANIMALS

28 adult horses that underwent abdominal surgery for colic.

PROCEDURE

14 horses were treated with each dosage of gentamicin (i.e., 6.6 or 4 mg/kg, i.v., q 24 h) and blood samples were collected for pharmacokinetic analysis. Plasma gentamicin concentrations were measured by use of a fluorescence polarization immunoassay. Pharmacokinetic analysis measured the elimination half-life, volume of distribution, and gentamicin total systemic clearance. Treatment outcome, CBC, and serum creatinine concentrations were recorded.

RESULTS

1 horse in the high-dosage group died. All other horses successfully recovered, and did not develop bacterial infection or have evidence of drug toxicosis resulting in renal injury. Mean pharmacokinetic variables for gentamicin administration at a high or low dosage (i.e., 6.6 or 4 mg/kg, i.v., q 24 h) were half-life of 1.47 and 1.61 hours, volume of distribution of 0.17 and 0.17 L/kg, and systemic clearance of 1.27 and 1.2 ml/kg/min, respectively. Mean serum creatinine concentration was 1.74 and 1.71 for the high and low dosages, respectively, and serum creatinine concentration was not correlated with gentamicin clearance.

CONCLUSIONS AND CLINICAL RELEVANCE

Gentamicin administration at a dosage of 4 mg/kg, i.v., every 24 hours, will result in plasma concentrations that are adequate against susceptible bacteria with a minimum inhibitory concentration (MIC) of < or = 2.0 micrograms/ml. Gentamicin administration at a calculated dosage of 6.8 mg/kg, i.v., every 24 hours will result in optimum plasma concentrations against susceptible bacteria with a MIC of < or = 4.0 micrograms/ml.

Effect of perioperative prophylactic antimicrobial treatment in dogs undergoing elective orthopedic surgery

OBJECTIVE

To determine whether perioperative antimicrobial prophylaxis would reduce incidence of postoperative infection among dogs undergoing elective orthopedic procedures.

DESIGN

Randomized, controlled, blinded, intention clinical trial.

ANIMALS

Dogs of any breed, sex, or age undergoing elective orthopedic surgery at a veterinary teaching hospital.

PROCEDURES

Dogs were randomly assigned to 1 of 3 groups: treatment with saline solution, treatment with potassium penicillin G, and treatment with cefazolin. Treatments were intended to be administered within 30 minutes prior to surgery; a second dose was administered if surgery lasted > 90 minutes. Dogs were monitored for 10 to 14 days after surgery for evidence of infection.

RESULTS

After the first 112 dogs were enrolled in the study, it was found that infection rate for control dogs (5/32 dogs) was significantly higher than the rate for dogs treated with antimicrobials (3/80 dogs). Therefore, no more dogs were enrolled in the study. A total of 126 dogs completed the study. Monte Carlo simulations indicated that compared with dogs that received antimicrobials prophylactically, dogs that received saline solution developed infections significantly more frequently. Difference in efficacy, however, was not observed between the 2 antimicrobial drugs used.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that perioperative antimicrobial prophylaxis decreased postoperative infection rate in dogs undergoing elective orthopedic surgery, compared with infection rate in control dogs. Cefazolin was not more efficacious than potassium penicillin G in these dogs.

Health and growth performance of barrows reared in all-in/all-out or continuous flow facilities with or without a chlortetracycline feed additive

OBJECTIVE

To compare health and growth performance in barrows reared in all-in/all-out (AIAO) or continuous flow (CF) management systems.

ANIMALS

400 barrows.

PROCEDURE

Barrows (approx 2 months old) were allotted to 4 replications (100 barrows each); barrows were housed in AIAO or CF rooms (10 pens/room), and 50 pigs/replicate received chlortetracycline (CTC, 110 mg/kg of feed). Barrows from each pen were slaughtered at 3, 4, 5, and 6 months old.

RESULTS

Barrows in the AIAO room had greater total daily gain (TDG) and lean daily gain (LDG) than did barrows in the CF room. Addition of CTC did not improve TDG or LDG in either environment. Barrows in the AIAO room reached body weight of 104.5 kg in 169.7 days, compared with 177.3 days for barrows in the CF room. Feed-to-gain ratio was not affected by management or CTC. Lungs from barrows reared in AIAO facilities had a lower percentage of lesions than did lungs of barrows reared in CF facilities (1.74% vs 9.52%). Addition of CTC did not affect prevalence and extent of lung lesions. Extent of lung lesions was positively correlated with change in serum optical density (OD) to Mycoplasma hyopneumoniae (r = 0.35), but not with change in serum OD to Actinobacillus pleuropneumoniae. Lean growth and serum OD to M. hyopneumoniae and A. pleuropneumoniae were not correlated.

CONCLUSIONS

Health and growth performance were better for barrows in an AIAO facility, compared with a CF facility, but addition of CTC to feed failed to enhance health or performance of barrows in either facility.

Surgical treatment of gastric leiomyoma in a dog

A 12-year-old entire male Maltese terrier was presented with a 1 month history of vomiting and haematemesis. Microcytic hypochromic anaemia was detected. Abdominal radiography, ultrasonography and gastric endoscopy identified a discrete intramural mass in the pyloric antrum. An ulcerated leiomyoma was removed by a partial-thickness intraluminal resection of the gastric wall. The dog recovered well and is free from clinical signs 20 months after surgery.

Pharmacokinetics, bioavailability and dosage regimen of sulphadimidine in camels (Camelus dromedarius) under hot, arid environmental conditions

A two-way crossover study was conducted in young Bikaneri camels (aged between 12 and 18 months) during the hot summer season to determine the bioavailability, pharmacokinetics and dosage regimens of sulphadimidine (SDM). A dose of 100 mg.kg-1 of SDM was used to study both the intravenous and oral pharmacokinetics of the drug. Analysis of the intravenous data according to a two-compartment pharmacokinetic model revealed that SDM was well distributed in the body (Vd(area):0.862 L.kg-1), had an overall body clearance of 0.035 +/- 0.019 L.h-1.kg-1 and the elimination of half-lives was in the range of 14.2 to 20.6 h. The mean maximum plasma SDM concentration following oral administration was 63.23 +/- 2.33 micrograms.mL-1, which was achieved 24 h after the oral administration. The mean bioavailability of SDM following oral administration was approximately 100%. To achieve and maintain the therapeutically satisfactory plasma sulphadimidine levels of > or = 50 micrograms.mL-1, the optimum dosage regimen for camels following either intravenous or oral administration would be 110 mg.kg-1 as the priming dose and 69 mg.kg-1 as the maintenance dose, to be repeated at 24 h intervals.