Salmonella enterica serovar Newport has undergone a rapid epidemic spread in dairy cattle. This provides an efficient mechanism for pathogen amplification and dissemination into the environment through manure spreading on agricultural land. The objective of this study was to determine the survival characteristics of Salmonella serovar Newport in manure and manure-amended soils where the pathogen may be amplified. A multidrug-resistant (MDR) Salmonella serovar Newport strain and a drug-susceptible (DS) strain, both bovine isolates, were inoculated into dairy manure that was incubated under constant temperature and moisture conditions alone or after being mixed with sterilized or nonsterilized soil. Salmonella serovar Newport concentrations increased by up to 400% in the first 1 to 3 days following inoculation, and a trend of steady decline followed. With manure treatment, a sharp decline in cell concentration occurred after day 35, possibly due to microbial antagonism. For all treatments, decreases in Salmonella serovar Newport concentrations over time fit a first-order kinetic model. Log reduction time was 14 to 32 days for 1 log 10 , 28 to 64 days for 2 log 10 , and 42 to 96 days for 3 log 10 declines in the organisms' populations from initially inoculated concentrations. Most-probable-number monitoring data indicated that the organisms persisted for 184, 332, and 405 days in manure, manure-amended nonsterilized soil, and manure-amended sterilized soil, respectively. The MDR strain and the DS strain had similar survival patterns.

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

BackgroundEquine neuroborreliosis (NB), Lyme disease, is difficult to diagnose and has limited description in the literature.ObjectiveProvide a detailed description of clinical signs, diagnostic, and pathologic findings of horses with NB.AnimalsSixteen horses with histologically confirmed NB.MethodsRetrospective review of medical records at the University of Pennsylvania and via an ACVIM listserv query with inclusion criteria requiring possible exposure to Borrelia burgdorferi and histologic findings consistent with previous reports of NB without evidence of other disease.ResultsSixteen horses were identified, 12 of which had additional evidence of NB. Clinical signs were variable including muscle atrophy or weight loss (12), cranial nerve deficits (11), ataxia (10), changes in behavior (9), dysphagia (7), fasciculations (6), neck stiffness (6), episodic respiratory distress (5), uveitis (5), fever (2), joint effusion (2), and cardiac arrhythmias (1). Serologic analysis was positive for B. burgdorferi infection in 6/13 cases tested. CSF abnormalities were present in 8/13 cases tested, including xanthochromia (4/13), increased total protein (5/13; median: 91 mg/dL, range: 25–219 mg/dL), and a neutrophilic (6/13) or lymphocytic (2/13) pleocytosis (median: 25 nucleated cells/μL, range: 0–922 nucleated cells/μL). PCR on CSF for B. burgdorferi was negative in the 7 cases that were tested.Conclusion and Clinical ImportanceDiagnosis of equine NB is challenging due to variable clinical presentation and lack of sensitive and specific diagnostic tests. Negative serology and normal CSF analysis do not exclude the diagnosis of NB.

Multidrug-resistant (MDR) strains of Salmonella enterica serotype Newport have been described for many years. However, the recognition of Newport strains with resistance to cephalosporin antibiotics is more recent. Plasmid-mediated CMY-2 AmpC ␤-lactamases have been identified in Salmonella in the United States, and the bla CMY-2 gene has been shown to be present in Salmonella serotype Newport. This organism is currently undergoing epidemic spread in both animals and humans in the United States, and this is to our knowledge the first description of the molecular epidemiology of this Salmonella strain in animals. Forty-two isolates were included in this study. All isolates were characterized by pulsed-field gel electrophoresis, plasmid analysis, and antibiogram. Four pulsed-field profiles with XbaI were observed. Plasmid analyses showed that although the majority of isolates harbored a single plasmid of 140 kb, this plasmid was not identical in all strains. All isolates showed the presence of the bla CMY gene by PCR. Integrons were detected in 16 of the 42 isolates; a fragment of approximately 1,000 bp, amplified with the intI-F and aadAI-R primers, confirmed the presence of the aadAI gene cassette within an integron in these 16 isolates. The potential for coselection of the bla CMY gene, if located on an MDR replicon, may not be dependent on any particular antibiotic but rather may be the result of more general antimicrobial use. If this replicon is mobile, it is to be expected that similar MDR strains of additional Salmonella serotypes will be recognized in due course.

Background: Nosocomial salmonellosis is an important problem for large animal veterinary teaching hospitals (VTHs). Objective: To describe failure of an Infection Control Program (ICP) that resulted in an outbreak of salmonellosis caused by Salmonella Newport multidrug resistant (MDR)-AmpC at a large animal VTH.Animals: Sixty-one animals identified with the outbreak strain of Salmonella. Methods: Retrospective study: Data collected included signalment, presenting complaint, duration of hospitalization, discharge status, and financial information. Phenotypic and genotypic characterization was performed on Salmonella isolates.Results: The outbreak occurred despite an existing ICP; the ICP was reviewed and weaknesses identified. Routine patient surveillance was not performed before or during the outbreak; fecal sampling was triggered only by a patient algorithm based on clinical signs. Sixty-one animals were infected with the outbreak strain of S. Newport, and the majority were horses (n 5 54). Case fatality rate was 36.1%. S. Newport isolates demonstrated high genetic similarity (Dice ! 0.96), and all had the MDRAmpC phenotype. Environmental persistence of the organism necessitated complete hospital closure, extensive decontamination, and remediation of the facility. A paradigm shift in the relevance of biosecurity in a VTH and the establishment of a stringent ICP were integral components of successful hospital reopening.Conclusions and Clinical Importance: An ineffective ICP resulted in a nosocomial outbreak caused by a MDR S. Newport in a VTH. Closure of a VTH affected all missions of the institution and had substantial financial impact (US$4.12 million).

While there was no difference in short-term outcome between groups, more horses with JI underwent a repeat celiotomy during hospitalisation. Horses with a JC were more likely to have long-term complications with colic. Horses that were subjected to euthanasia because of colic within 12 months of hospital discharge either had a JC or repeat celiotomy. The results suggest that, when possible, a JI may be the preferred method of anastomosis based on more favourable survival and lower occurrence of colic long term.

No abstract

These results should help direct future research with regard to investigation of risk factors for equine MRSA infection in community and hospital populations.