Molecular characterization of gentamicin-resistant Enterococci in the United States: evidence of spread from animals to humans through food.
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We evaluated the molecular mechanism for resistance of 360 enterococci for which the gentamicin MICs were >/=128 micro g/ml. The aac(6')-Ie-aph(2")-Ia, aph(2")-Ic, and aph(2")-Id genes were identified by PCR in isolates from animals, food, and humans. The aph(2")-Ib gene was not identified in any of the isolates. Two Enterococcus faecalis isolates (MICs > 1,024 micro g/ml) from animals failed to generate a PCR product for any of the genes tested and likely contain a new unidentified aminoglycoside resistance gene. Pulsed-field gel electrophoresis (PFGE) analysis showed a diversity of strains. However, 1 human and 18 pork E. faecalis isolates from Michigan with the aac(6')-Ie-aph(2")-Ia gene had related PFGE patterns and 2 E. faecalis isolates from Oregon (1 human and 1 grocery store chicken isolate) had indistinguishable PFGE patterns. We found that when a gentamicin-resistant gene was present in resistant enterococci from animals, that gene was also present in enterococci isolated from food products of the same animal species. Although these data indicate much diversity among gentamicin-resistant enterococci, the data also suggest similarities in gentamicin resistance among enterococci isolated from humans, retail food, and farm animals from geographically diverse areas and provide evidence of the spread of gentamicin-resistant enterococci from animals to humans through the food supply. (+info)
Detection of Ehrlichia spp. in the blood of wild white-tailed deer in Missouri by PCR assay and serologic analysis.
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Blood samples collected from wild deer in Missouri in November of 2000 and 2001 were positive by PCR assays for Ehrlichia chaffeensis (50 of 217; 23%), Ehrlichia ewingii (44 of 217; 20%), and Anaplasma species (214 of 217; 99%). Nucleotide sequences of selected amplicons from the assay for anaplasma matched sequences of the white-tailed deer agent. Serologic analysis of 112 deer sampled in 2000 showed a very high prevalence of antibodies to E. chaffeensis (97 of 112; 87%) and a low prevalence of antibodies reactive with Anaplasma phagocytophila (2 of 112; 2%). (+info)
Leucotoxic activities of Staphylococcus aureus strains isolated from cows, ewes, and goats with mastitis: importance of LukM/LukF'-PV leukotoxin.
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Among the toxins that Staphylococcus aureus is able to secrete, bi-component toxins named leukotoxins target specifically leukocytes, mainly phagocytic cells. Isolates from cows, goats and ewes with mastitis were selected on the basis of the presence or not of the genes encoding the recently described LukM/LukF'-PV leukotoxin. Of the 128 isolates tested, 126 had moderate to high leukotoxic activity to bovine polymorphonuclear cells (PMN). The supernatants of lukM-positive isolates were much more leukotoxic than the supernatants of lukM-negative isolates: mean leukotoxic titers were 122 versus 20 and 581 versus 26 for isolates of bovine and caprine origin, respectively. Among lukM/lukF'-PV positive isolates, those of caprine and ovine origins were more leukotoxic than were isolates of bovine origin (P < 0.01). The two most abundant proteins in the culture supernatant of a highly toxic isolate were purified and identified as the two components of LukM (LukM and LukF'-PV) on the basis of their molecular mass, N-terminal amino acid sequence, and high synergistic activity. LukM/LukF'-PV induced the flattening of bovine PMN at a concentration as low as 3.6 ng/ml (0.1 nM). A higher concentration (18 ng/ml) was necessary to produce the same effect on caprine or ovine PMN. Affinity-purified antibodies to LukM or to LukF'-PV neutralized the leukotoxic effect of all the culture supernatants. They neutralized with the same efficiency the toxic activity of supernatants from lukM/lukF'-PV positive or negative isolates. These results establish that LukM/LukF'-PV is very active on PMN of ruminants and suggest that this leukotoxin could be the most active leukotoxin produced by mastitis isolates. They prompt further studies to delineate the contribution of LukM/LukF'-PV to the pathogenesis of mastitis in ruminants and the protective effect of antibodies to this leukotoxin. (+info)
A comparative study of white blood cell counts and disease risk in carnivores.
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In primates, baseline levels of white blood cell (WBC) counts are related to mating promiscuity. It was hypothesized that differences in the primate immune system reflect pathogen risks from sexually transmitted diseases (STDs). Here, we test for the generality of this result by examining hypotheses involving behavioural, ecological and life-history factors in carnivores. Again, we find a significant correlation in carnivores between mating promiscuity and elevated levels of WBC counts. In addition, we find relationships with measures of sociality, substrate use and life-history parameters. These comparative results across independent taxonomic orders indicate that the evolution of the immune system, as represented by phylogenetic differences in basal levels of blood cell counts, is closely linked to disease risk involved with promiscuous mating and associated variables. We found only limited support for an association between the percentage of meat in the diet and WBC counts, which is consistent with the behavioural and physiological mechanisms that carnivores use to avoid parasite transmission from their prey. We discuss additional comparative questions related to taxonomic differences in disease risk, modes of parasite transmission and implications for conservation biology. (+info)
Linking human and veterinary health: trends, directions and initiatives.
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The objective of this brief article is to provide an overview of some of the important harmonization efforts that are currently under way within the animal health community. Topics include: scientific networks and interdisciplinary communication; organizations that address animal-related public health concerns; the role of the veterinary pharmaceutical scientist within human health-oriented professional organizations; recent publications pertaining to veterinary pharmacology, pharmaceutics and therapeutics; and the role of global networking in veterinary product research and development. (+info)
Evolving importance of biologics and novel delivery systems in the face of microbial resistance.
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Methods to control infectious diseases in livestock are growing in importance. As the size of the average farm increases - for poultry, dairy and beef cattle, swine, and fish - the risk of rapid spread of infectious diseases increases as well. This increases the need for alternative methods of control of infectious agents. Improvements in specific immunogens, adjuvants, and delivery systems are needed to meet the demand for vaccines to ensure a healthy and safe meat supply. This article explores the challenges, trends, and recent advances in the control of infectious diseases through the use of biologics. (+info)
Introduction: a welcome to the First Special Animal Health Issue of AAPS PharmSci.
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The goal of this special volume is to provide veterinary scientists with state-of-the art reviews in animal health and to inform human health scientists of the various challenges and collaborative opportunities associated with their animal health counterparts. The contributors are highly respected experts, providing invaluable insights into current issues and state-of-the-art advances within veterinary medicine. (+info)
Seroprevalence of OHV-2, BVDV, BHV-1, and BRSV in ranch-raised bison (Bison bison).
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Serum samples were collected at slaughter from 226 24-30-month-old American bison (Bison bison) bulls from Kansas, Minnesota, North Dakota, and Manitoba and assayed for antibodies to ovine herpesvirus type-2 (OHV-2), bovine viral diarrhea virus (BVDV), bovine herpesvirus type-1 (BHV-1), and bovine respiratory syncytial virus (BRSV). Antibodies were detected by serum neutralization for BVDV, BHV-1, and BRSV, while antibodies to OHV-2 were detected by competitive inhibition-ELISA (CI-ELISA). Detectable antibodies were found against all viruses: 10 of 226 (4.40%) against OHV-2, 125 of 226 (55.3%) against BVDV, 99 of 226 (43.8%) against BHV-1, and 208 of 226 (92.0%) against BRSV. Titers from 93.6% of the BVDV-positive animals, 79.8% of the BHV-1-positive animals, and 98.1% of the BRSV-positive animals were > or = 1.25. These data indicate that a low percentage of clinically normal bison are seropositive for OHV-2 while a high percentage of bison sampled are seropositive for BVDV, BHV-1, and BRSV. (+info)