Featured Publications:
Florfenicol is an important antibiotic in veterinary medicine that is used extensively in aquaculture, including salmon farming in Chile. We analysed a set of 119 florfenicol-resistant Gram-negative bacilli from seven freshwater Chilean salmon farms for the molecular determinants involved in the florfenicol resistance. Ninety-seven of these strains were glucose non-fermenting bacilli, mainly belonging to the…
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Large multidrug resistance plasmids of the A/C incompatibility complex (IncA/C) have been found in a diverse group of Gram-negative commensal and pathogenic bacteria. We present three completed sequences from IncA/C plasmids that originated from Escherichia coli (cattle) and Salmonella enterica serovar Newport (human) and that carry the cephamycinase gene blaCMY-2. These large plasmids (148 to…
Read MoreObjective: To evaluate the bactericidal activity of seven commercial disinfectants against Lawsonia intracellularis using a tissue culture system. Materials and methods: Two L intracellularis isolates were tested for susceptibility to several classes of disinfectants, including iodine, a biguanide, phenol, an oxidizing agent, a quaternary ammonium compound (QAC), and the combinations of QACs with aldehydes (formaldehyde and glutaraldehyde). All disinfectants were diluted…
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The objective of this study was to determine the in vitro efficacy of Stalosan F, a mixed chemical and heavy metal disinfectant, against two strains of Lawsonia intracellularis using both a modified tissue culture and a direct count method. For testing as a powder, 1g, 0.5g, or 0.25g of Stalosan F was applied to…
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Cultivation methods are commonly used in Salmonella surveillance systems and outbreak investigations, and consequently, conclusions about Salmonella evolution and transmission are highly dependent on the performance characteristics of these methods. Past studies have shown that Salmonella serotypes can exhibit different growth characteristics in the same enrichment and selective media. This could lead not only to…
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The objective of this study was to determine the in vitro minimum inhibitory concentration (MIC) of antimicrobials against 10 isolates of Lawsonia intracellularis, the etiological agent of proliferative enteropathy (PE). Antimicrobials tested included carbadox, chlortetracycline, lincomycin, tiamulin, tylosin and valnemulin. The MIC of each antimicrobial against L. intracellularis was determined using a tissue culture system…
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The origins and virulence potential of fluoroquinolone-resistant (FQ-R) Escherichia coli from dogs with urinary tract infection (UTI) are undefined. Therefore, fluoroquinolone-resistant (n=38) or susceptible (n=62) E. coli urine isolates from dogs with UTI were characterized for phylogenetic group (A, B1, B2, D) and 61 virulence-associated genes by multiplex PCR, then were compared according to these…
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OBJECTIVE: To estimate seroprevalence of antibodies against the serogroup of epizootic hemorrhagic disease viruses (EHDVs) and describe spatial distribution of antibodies against EHDV among cattle herds in Illinois and western Indiana. SAMPLE POPULATION: 9,414 serum samples collected from cattle in 60 herds over 3 transmission seasons. PROCEDURES: Serum samples were tested for antibodies against EHDV…
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Singer RS, Patterson SK, Wallace RL Applied and Environmental Microbiology 74(22):6956-62 The goal of this study was to follow ceftiofur-treated and untreated cattle in a normally functioning dairy to examine enteric Escherichia coli for changes in antibiotic resistance profiles and genetic diversity. Prior to treatment, all of the bacteria cultured from the cows were susceptible…
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Paulin-Curlee, GG, Sreevatsan S, Singer RS, Isaacson R, Reneau J, Bey R, Foster D Journal of Dairy Science 91:554-563 Despite advances in controlling mastitis (inflammation of the mammary gland), udder infections caused by Klebsiella pneumoniae continue to affect dairy cattle. Mastitis caused by K. pneumoniae responds poorly to antibiotic treatment, and as a consequence, infections…
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French BC, Hird DW, Romano PS, Hayes RH, Nijhof AM, Jongejan F, Mellor DJ, Singer RS, Fine AE, Gay JM, Davis RG, Conrad PA Journal of Veterinary Medical Education 34:502-509 While many studies have evaluated whether or not factual information can be effectively communicated using computer-aided tools, none has focused on establishing and changing students’…
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Boyer TC, Ward MP, Wallace RL, Singer RS American Journal of Veterinary Research 68:1212-1219 OBJECTIVE: To estimate seroprevalence of bluetongue virus (BTV) and the geographic distribution of seropositive cattle herds in Illinois and western Indiana. SAMPLE POPULATION: 10,585 serum samples obtained from cattle in 60 herds during 3 transmission seasons (2000 through 2002). PROCEDURES: In…
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Paulin-Curlee GG, Singer RS, Sreevatsan S, Isaacson R, Reneau J, Foster D, Bey R Journal of Dairy Science 90:3681-3689 The objectives of this study were to determine the level of genetic diversity of Klebsiella pneumoniae isolated from clinical mastitis cases and to define genotypes most commonly associated with the disease. Individual quarter milk samples were…
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Antibiotics and antibiotic metabolites have been found in the environment, but the biological activities of these compounds are uncertain, especially given the low levels that are typically detected in the environment. The objective of this study was to estimate the selection potential of chlortetracycline (CTC) on the antibiotic resistance of aerobic bacterial populations in…
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To achieve further reductions in foodborne illness levels in humans, effective pre-harvest interventions are needed. The health status of food animals that are destined to enter the human food supply chain may be an important, although often overlooked, factor in predicting the risk of human foodborne infections. The health status of food animals can potentially…
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