@article{gonçalves_lyman_hockett_rodriguez_dos santos_anderson_2017, title={Using milk leukocyte differentials for diagnosis of subclinical bovine mastitis}, volume={84}, ISSN={0022-0299 1469-7629}, url={http://dx.doi.org/10.1017/S0022029917000267}, DOI={10.1017/s0022029917000267}, abstractNote={This research study aimed to evaluate the use of the milk leukocyte differential (MLD) to: (a) identify quarter milks that are culture-positive; and (b) characterize the milk leukocyte responses to specific groups of pathogens causing subclinical mastitis. The MLD measures the absolute number and relative percentage of inflammatory cells in milk samples. Using the MLD in two dairy herds (170 and 172 lactating cows, respectively), we studied all lactating cows with a most recent monthly Dairy Herd Improvement Association somatic cell count (SCC) >200 × 103 cells/ml. Quarter milk samples from 78 cows meeting study criteria were analysed by MLD and aseptically collected milk samples were subjected to microbiological culture (MC). Based upon automated instrument evaluation of the number and percentage of inflammatory cells in milk, samples were designated as either MLD-positive or – negative for subclinicial mastitis. Positive MC were obtained from 102/156 (65·4%) of MLD-positive milk samples, and 28/135 (20·7%) of MLD-negative milk samples were MC-positive. When MC was considered the gold standard for mastitis diagnosis, the calculated diagnostic Se of the MLD was 65·4% (IC95% = 57·4 to 72·8%) and the Sp was 79·3% (IC95% = 71·4 to 85·7%). Quarter milks positive on MC had higher absolute numbers of neutrophils, lymphocytes and macrophages, with higher neutrophils% and lymphocytes% but lower macrophages%. The Log10 (N/L) ratios were the most useful ratio to differentiate specific subclinical mastitis quarters from healthy quarters. Use of the MLD on cows with monthly composite SCC > 200 × 103 cells/ml for screening at quarter level identified quarters more likely to be culture-positive.}, number={3}, journal={Journal of Dairy Research}, publisher={Cambridge University Press (CUP)}, author={Gonçalves, Juliano Leonel and Lyman, Roberta L. and Hockett, Mitchell and Rodriguez, Rudy and dos Santos, Marcos Veiga and Anderson, Kevin L.}, year={2017}, month={Jun}, pages={309–317} }
 @article{mullen_lee_lyman_mason_washburn_anderson_2014, title={Short communication: An in vitro assessment of the antibacterial activity of plant-derived oils}, volume={97}, ISSN={["1525-3198"]}, DOI={10.3168/jds.2013-7806}, abstractNote={Nonantibiotic treatments for mastitis are needed in organic dairy herds. Plant-derived oils may be useful but efficacy and potential mechanisms of action of such oils in mastitis therapy have not been well documented. The objective of the current study was to evaluate the antibacterial activity of the plant-derived oil components of Phyto-Mast (Bovinity Health LLC, Narvon, PA), an herbal intramammary product, against 3 mastitis-causing pathogens: Staphylococcus aureus, Staphylococcus chromogenes, and Streptococcus uberis. Plant-derived oils evaluated were Thymus vulgaris (thyme), Gaultheria procumbens (wintergreen), Glycyrrhiza uralensis (Chinese licorice), Angelica sinensis, and Angelica dahurica. Broth dilution testing according to standard protocol was performed using ultrapasteurized whole milk instead of broth. Controls included milk only (negative control), milk + bacteria (positive control), and milk + bacteria + penicillin-streptomycin (antibiotic control, at 1 and 5% concentrations). Essential oil of thyme was tested by itself and not in combination with other oils because of its known antibacterial activity. The other plant-derived oils were tested alone and in combination for a total of 15 treatments, each replicated 3 times and tested at 0.5, 1, 2, and 4% to simulate concentrations potentially achievable in the milk within the pre-dry-off udder quarter. Thyme oil at concentrations ≥2% completely inhibited bacterial growth in all replications. Other plant-derived oils tested alone or in various combinations were not consistently antibacterial and did not show typical dose-response effects. Only thyme essential oil had consistent antibacterial activity against the 3 mastitis-causing organisms tested in vitro. Further evaluation of physiological effects of thyme oil in various preparations on mammary tissue is recommended to determine potential suitability for mastitis therapy.}, number={9}, journal={JOURNAL OF DAIRY SCIENCE}, author={Mullen, K. A. E. and Lee, A. R. and Lyman, R. L. and Mason, S. E. and Washburn, S. P. and Anderson, K. L.}, year={2014}, month={Sep}, pages={5587–5591} }
 @article{azizoglu_lyman_anderson_2013, title={Bovine Staphylococcus aureus: Dose response to iodine and chlorhexidine and effect of iodine challenge on antibiotic susceptibility}, volume={96}, ISSN={["0022-0302"]}, DOI={10.3168/jds.2012-5857}, abstractNote={Staphylococcus aureus is a gram-positive organism that is frequently associated with clinical or subclinical mastitis. The use of germicidal teat dips is one of the measures taken by the dairy industry to control mastitis. Iodine and chlorhexidine compounds are commonly used disinfectants in teat dips. We determined the minimum inhibitory concentrations (MIC) of iodine for 37 isolates of Staph. aureus and observed variations in MIC. Seven of these Staph. aureus isolates were selected as genotype group representatives based on their pulsed-field gel electrophoresis patterns. Dose responses against iodine and chlorhexidine were determined for the 7 genotype group representatives. The response of these isolates to iodine varied significantly, whereas all isolates were susceptible to chlorhexidine, even at concentrations as low as 0.0002%. We also evaluated whether exposure of Staph. aureus to sublethal levels of iodine influenced subsequent antibiotic susceptibility. No differences in antibiotic susceptibility of Staph. aureus were observed among cultures grown in brain heart infusion broth with and without supplemental iodine. The observed variation in iodine dose responses of Staph. aureus may have implications for the occurrence of Staph. aureus mastitis on dairy farms.}, number={2}, journal={JOURNAL OF DAIRY SCIENCE}, author={Azizoglu, Reha Onur and Lyman, Roberta and Anderson, Kevin L.}, year={2013}, month={Feb}, pages={993–999} }
 @article{robbins_suyemoto_lyman_martin_barnes_borst_2012, title={An Outbreak and Source Investigation of Enterococcal Spondylitis in Broilers Caused by Enterococcus cecorum}, volume={56}, ISSN={["0005-2086"]}, DOI={10.1637/10253-052412-case.1}, abstractNote={SUMMARY. Enterococcus cecorum was isolated from spondylitis lesions in broilers from two flocks in North Carolina that were experiencing increased mortality. Affected birds showed paresis and paralysis, clinical signs characteristic of enterococcal spondylitis (ES). Affected birds rested on their hocks and caudal abdomens with legs extended forward and were unable to stand or walk. Necropsy examination of affected birds revealed firm to hard inflammatory masses involving the vertebral bodies at the level of the free thoracic vertebra that bulged dorsally and compressed the spinal cord. When opened, lesions contained pale, tan to yellow caseonecrotic material. Microscopically, necrosis and fibrinoheterophilic spondylitis with intralesional gram-positive bacteria were seen. Heavy growth of E. cecorum recovered from vertebral lesions confirmed the diagnosis of ES. To investigate possible sources of the organism for one of the flocks bacterial cultures were made from the environment, water lines, mice trapped on the farm, cecal/cloacal swabs from one of the parent broiler breeder flocks, egg residue, hatching eggs, and the hatchery environment. Except for cecal/cloacal swabs from the breeders, E. cecorum was not isolated from any of these samples. When compared phenotypically and genotypically, cecal/cloacal isolates of E. cecorum from the breeders differed from isolates from spondylitis lesions in the broilers. The source of E. cecorum for the broiler flocks was not determined, but vertical transmission appears unlikely.}, number={4}, journal={AVIAN DISEASES}, author={Robbins, Kabel M. and Suyemoto, M. Mitsu and Lyman, Roberta L. and Martin, Michael P. and Barnes, H. John and Borst, Luke B.}, year={2012}, month={Dec}, pages={768–773} }
 @article{borst_suyemoto_robbins_lyman_martin_barnes_2012, title={Molecular epidemiology of Enterococcus cecorum isolates recovered from enterococcal spondylitis outbreaks in the southeastern United States}, volume={41}, ISSN={["1465-3338"]}, DOI={10.1080/03079457.2012.718070}, abstractNote={Enterococcus cecorum, a normal intestinal inhabitant, is increasingly responsible for outbreaks of arthritis and osteomyelitis in chickens worldwide. Enterococcal spondylitis (ES) is a specific manifestation of E. cecorum-associated disease in which increased flock morbidity and mortality result from chronic infection involving the free thoracic vertebra. In this study the genetic relatedness and antimicrobial resistance of isolates recovered from ES-affected flocks in the southeastern United States were determined. ES outbreaks from 2007 to 2011 were investigated in North Carolina (15 flocks, 13 farms, four integrators), South Carolina (one flock, one farm, one integrator) and Alabama (six flocks, six farms, one integrator). From these 22 epidemiologically distinct outbreaks, 326 isolates of E. cecorum were recovered. Isolates from spinal lesions and caeca of affected birds (cases) and caeca of unaffected birds (controls) were genotyped using pulsed-field gel electrophoresis; phenotyped using both GenIII MicroPlate™ (Biolog; Hayward, CA, USA) microbial identification plates and antimicrobial sensitivity testing; and compared with each other. Isolates from spinal lesions were incapable of mannitol metabolism and the majority of these isolates were genetically clonal. In contrast, caecal isolates from control birds varied in their ability to metabolize mannitol and were genetically diverse. Isolates from both case and control birds had high levels of antimicrobial resistance. These findings indicate that the increase in E. cecorum-associated disease in the southeast United States is due to the emergence of new clones with increased pathogenicity and multidrug resistance.}, number={5}, journal={AVIAN PATHOLOGY}, author={Borst, Luke B. and Suyemoto, M. Mitsu and Robbins, Kabel M. and Lyman, Roberta L. and Martin, Michael P. and Barnes, H. John}, year={2012}, pages={479–485} }
 @article{anderson_lyman_moury_ray_watson_correa_2012, title={Molecular epidemiology of Staphylococcus aureus mastitis in dairy heifers}, volume={95}, ISSN={["1525-3198"]}, DOI={10.3168/jds.2011-4913}, abstractNote={The specific purpose was to investigate the possible interrelationships of genotypes of Staphylococcus aureus found in mammary glands, horn flies, and extramammary sites on 3 southeastern US dairies. A total of 1,228 samples were obtained from various sources on the 3 dairy herds, each of which had a history of Staph. aureus mastitis. Dairy herds studied had access to pasture, and samples were collected during the summer when horn flies (Haematobia irritans) were active. Samples collected included milk samples from all lactating herd cows, colostrum samples from heifers calving during the study period, heifer body sites (mouth, nostrils, and teats), the heifer environment (water, feed, and soil/vegetation/pasture), horn flies, and humans (hands and nostrils). Isolation of Staph. aureus was attempted from all samples, with isolates subjected to genotypic analysis using pulsed-field gel electrophoresis. A total of 244/1228 (or 19.9%) of all samples were positive for Staph. aureus. For milk samples, 52/383 (or 13.6%) of samples were Staph. aureus positive, and 70/411 (or 17.0%) of heifer quarter colostrum samples were positive. Horn fly samples were frequently positive, with over one-half (29/52, or 55.8%) of samples positive for Staph. aureus. Staphylococcus aureus obtained during the study comprised isolates from 12 different genotype groups as defined in this study. Identical genotypes were obtained from horn flies, heifer colostrum samples, and cow milk samples. Group B genotypes were shared among flies, heifer colostrum samples, body sites, and cow milk samples, whereas group A genotypes were common to the same sample locations and body sites but rarely (once) found in horn flies. We conclude, based upon the finding of identical pulsed-field gel electrophoresis genotypes in flies, heifer body sites, and heifer colostrum samples, that flies and heifer body sites could be important sources of Staph. aureus for heifer intramammary infections.}, number={9}, journal={JOURNAL OF DAIRY SCIENCE}, author={Anderson, K. L. and Lyman, R. and Moury, K. and Ray, D. and Watson, D. W. and Correa, M. T.}, year={2012}, month={Sep}, pages={4921–4930} }
 @article{ferreira_anderson_correa_lyman_ruffin_reller_fowler_2011, title={Transmission of MRSA between Companion Animals and Infected Human Patients Presenting to Outpatient Medical Care Facilities}, volume={6}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0026978}, abstractNote={Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen in both human and veterinary medicine. The importance of companion animals as reservoirs of human infections is currently unknown. The companion animals of 49 MRSA-infected outpatients (cases) were screened for MRSA carriage, and their bacterial isolates were compared with those of the infected patients using Pulsed-Field Gel Electrophoresis (PFGE). Rates of MRSA among the companion animals of MRSA-infected patients were compared to rates of MRSA among companion animals of pet guardians attending a “veterinary wellness clinic” (controls). MRSA was isolated from at least one companion animal in 4/49 (8.2%) households of MRSA-infected outpatients vs. none of the pets of the 50 uninfected human controls. Using PFGE, patient-pets MRSA isolates were identical for three pairs and discordant for one pair (suggested MRSA inter-specie transmission p-value = 0.1175). These results suggest that companion animals of MRSA-infected patients can be culture-positive for MRSA, representing a potential source of infection or re-infection for humans. Further studies are required to better understand the epidemiology of MRSA human-animal inter-specie transmission.}, number={11}, journal={PLOS ONE}, author={Ferreira, Jorge Pinto and Anderson, Kevin L. and Correa, Maria T. and Lyman, Roberta and Ruffin, Felicia and Reller, L. Barth and Fowler, Vance G., Jr.}, year={2011}, month={Nov} }
 @article{ferreira_fowler_correa_lyman_ruffin_anderson_2011, title={Transmission of Methicillin-Resistant Staphylococcus aureus between Human and Hamster}, volume={49}, ISSN={["1098-660X"]}, DOI={10.1128/jcm.02469-10}, abstractNote={ABSTRACT}, number={4}, journal={JOURNAL OF CLINICAL MICROBIOLOGY}, author={Ferreira, Jorge Pinto and Fowler, Vance G., Jr. and Correa, Maria T. and Lyman, Roberta and Ruffin, Felicia and Anderson, Kevin L.}, year={2011}, month={Apr}, pages={1679–1680} }
 @article{rivas_anderson_lyman_smith_schwager_2008, title={Proof of concept of a method that assesses the spread of microbial infections with spatially explicit and non-spatially explicit data}, volume={7}, ISSN={["1476-072X"]}, DOI={10.1186/1476-072x-7-58}, abstractNote={A method that assesses bacterial spatial dissemination was explored. It measures microbial genotypes (defined by electrophoretic patterns or EP), host, location (farm), interfarm Euclidean distance, and time. Its proof of concept (construct and internal validity) was evaluated using a dataset that included 113 Staphylococcus aureus EPs from 1126 bovine milk isolates collected on 23 farms between 1988 and 2005.Construct validity was assessed by comparing results based on the interfarm Euclidean distance (a spatially explicit measure) and those produced by the (non-spatial) interfarm number of isolates reporting the same EP. The distance associated with EP spread correlated with the interfarm number of isolates/EP (r = .59, P < 0.02). Internal validity was estimated by comparing results obtained with different versions of the same indices. Concordance was observed between: (a) EP distance (estimated microbial dispersal over space) and EP speed (distance/year, r = .72, P < 0.01), and (b) the interfarm number of isolates/EP (when measured on the basis of non-repeated cow testing) and the same measure as expressed by repeated testing of the same animals (r = .87, P < 0.01). Three EPs (2.6% of all EPs) appeared to be super-spreaders: they were found in 26.75% of all isolates. Various indices differentiated local from spatially disseminated infections and, within the local type, infections suspected to be farm-related were distinguished from cow-related ones.Findings supported both construct and internal validity. Because 3 EPs explained 12 times more isolates than expected and at least twice as many isolates as other EPs did, false negative results associated with the remaining EPs (those erroneously identified as lacking spatial dispersal when, in fact, they disseminated spatially), if they occurred, seemed to have negligible effects. Spatial analysis of laboratory data may support disease surveillance systems by generating hypotheses on microbial dispersal ability.}, journal={INTERNATIONAL JOURNAL OF HEALTH GEOGRAPHICS}, author={Rivas, Ariel L. and Anderson, Kevin L. and Lyman, Roberta and Smith, Stephen D. and Schwager, Steven J.}, year={2008}, month={Nov} }
 @article{smith_lyman_anderson_2006, title={Efficacy of vaccination and antimicrobial treatment to eliminate chronic intramammary Staphylococcus aureus infections in dairy cattle}, volume={228}, ISSN={0003-1488}, url={http://dx.doi.org/10.2460/javma.228.3.422}, DOI={10.2460/javma.228.3.422}, abstractNote={Abstract}, number={3}, journal={Journal of the American Veterinary Medical Association}, publisher={American Veterinary Medical Association (AVMA)}, author={Smith, Geof W. and Lyman, Roberta L. and Anderson, Kevin L.}, year={2006}, month={Feb}, pages={422–425} }
 @article{anderson_lyman_bodeis-jones_white_2006, title={Genetic diversity and antimicrobial susceptibility profiles among mastitis-causing Staphylococcus aureus isolated from bovine milk samples}, volume={67}, ISSN={["1943-5681"]}, DOI={10.2460/ajvr.67.7.1185}, abstractNote={Abstract}, number={7}, journal={AMERICAN JOURNAL OF VETERINARY RESEARCH}, author={Anderson, Kevin L. and Lyman, Roberta L. and Bodeis-Jones, Sonya M. and White, David G.}, year={2006}, month={Jul}, pages={1185–1191} }
 @article{anderson_lyman_2006, title={Long-term persistence of specific genetic types of mastitis-causing Staphylococcus aureus on three dairies}, volume={89}, ISSN={["0022-0302"]}, DOI={10.3168/jds.S0022-0302(06)72504-8}, abstractNote={Pulsed-field gel electrophoresis (PFGE) after SmaI digestion was used to investigate the persistence of specific genotypes of bovine mammary gland isolates of Staphylococcus aureus on 3 dairy herds. A total of 341 isolates of Staph. aureus were available from cows in 3 herds, collected over a period of 15 yr. Pulsed-field gel electrophoresis band patterns of Staph. aureus isolates were analyzed visually and with gel analysis and comparison software. Based on this analysis, isolates were classified by PFGE type. Persistence was determined as the time period from the first to the last isolation of a particular PFGE type of Staph. aureus within a herd. Specific types of mastitis-causing Staph. aureus persisted long-term on these dairies. For example, PFGE type 3 isolates persisted on farms A, B, and C for 15, 15, and 13 yr, respectively. Type 6 was found to persist for 13 yr on farm C. Despite the application of standard mastitis control practices, mastitis-causing Staph. aureus types appeared to persist long-term, as detected by PFGE, and were isolated coincident with herd problems of increased milk somatic cell counts and decreased milk production.}, number={12}, journal={JOURNAL OF DAIRY SCIENCE}, author={Anderson, K. L. and Lyman, R. L.}, year={2006}, month={Dec}, pages={4551–4556} }
 @article{hanway_hansen_anderson_lyman_rushing_2005, title={Inactivation of penicillin G in milk using hydrogen peroxide}, volume={88}, ISSN={["1525-3198"]}, DOI={10.3168/jds.S0022-0302(05)72707-7}, abstractNote={Milk antibiotic residues have been a public concern in recent years. The Grade A Pasteurized Milk Ordinance mandates that raw Grade A milk will test negative for beta-lactam antibiotic residues before processing. The purpose of this research was to investigate the ability of various levels of peroxide and heat to inactivate penicillin G in raw milk. Whole milk spiked to a mean of 436 +/- 15.1 (standard error of the mean) ppb of potassium penicillin G was treated with hydrogen peroxide at levels of 0.0, 0.09, 0.17, and 0.34%. Samples at each peroxide level (n = 6 per treatment) were treated as follows: 1) incubated at 54.4 degrees C for 3 h, 2) pasteurized at 62.8 degrees C for 30 min, 3) incubated and pasteurized as in treatments 1 and 2, or 4) received no further treatment. A beta-lactam competitive microbial receptor assay was used for quantification of penicillin G. Concentrations of penicillin in selected samples were determined by HPLC for a comparison of test methods. Treatments were evaluated relative to their ability to reduce milk penicillin G levels to below the safe level of 5 ppb. The 0.09% hydrogen peroxide level was ineffective for all treatments. Hydrogen peroxide at 0.17% lowered the mean penicillin G (+/- SEM) from 436 +/- 15.1 to 6 +/- 1.49 ppb using the incubated and pasteurized heat treatment. The 0.34% concentration of hydrogen peroxide was the most effective, inactivating penicillin G to a level well below the safe level of 5 ppb with the pasteurized heat treatment, with or without incubation.}, number={2}, journal={JOURNAL OF DAIRY SCIENCE}, author={Hanway, WH and Hansen, AP and Anderson, KL and Lyman, RL and Rushing, JE}, year={2005}, month={Feb}, pages={466–469} }
 @article{anderson_lyman_2002, title={Comparison of microbial receptor assay and liquid chromatography for determination of penicillin G and amoxicillin in milk powder}, volume={85}, number={3}, journal={Journal of AOAC International}, author={Anderson, K. L. and Lyman, R. L.}, year={2002}, pages={546–550} }
 @article{smith_spooner_lyman_george_kloos_anderson_2002, title={Distribution of strains of Staphylococcus aureus isolated from milk of cows in North Carolina}, volume={41}, number={2002}, journal={Annual Meeting, National Mastitis Council, Inc}, author={Smith, P. and Spooner, C. and Lyman, R. and George, C. and Kloos, W. and Anderson, K.}, year={2002}, pages={233–234} }
 @article{baynes_lyman_anderson_brownie_1999, title={A preliminary survey of antibiotic residues and viable bacteria in milk from three Caribbean basin countries}, volume={62}, ISSN={["1944-9097"]}, DOI={10.4315/0362-028X-62.2.177}, abstractNote={There is widespread concern about the presence of antimicrobial drugs in milk. The presence of drug residues in milk may have public health implications. Milk samples (n = 25 to 65/country) were collected from bulk tanks and commercial vendors in Barbados, Costa Rica, and Jamaica between February 1996 and August 1997. Bulk tank samples were collected from high milk-producing regions of Jamaica and Costa Rica and from 26 dairy farms in Barbados. Milk pH, bacterial growth (total CFU/ml and the presence of Streptococcus agalactiae and Staphylococcus aureus), and the presence of antimicrobials were determined. Milk samples were tested by a microbial inhibition test (Delvotest-P, Gist-Brocades Food Ingredients, Inc.) to screen for antimicrobial drugs. All positives were retested for the presence of beta-lactam antibiotics after incubating with penicillinase and some positives were identified by high-pressure liquid chromatography-UV. Mean pH values ranged from 6.5 to 6.7. S. aureus was identified in bulk tank samples from Costa Rica (52%), Barbados (44%), and Jamaica (46%). S. agalactiae was identified in bulk tank samples from Costa Rica (28%), Barbados (8 and 16%), and Jamaica (18%). Antimicrobial residues were detected in some bulk tank samples from Barbados (8%) and Jamaica (10%) but not in samples from Costa Rica. All positives in milk from Jamaica and Barbados were determined to be beta-lactams. No residues were detected in pasteurized milk samples from Barbados or ultrahigh-temperature milk from Jamaica. The presence of beta-lactam residues in some of these samples suggests the appropriateness of testing milk prior to processing for consumption.}, number={2}, journal={JOURNAL OF FOOD PROTECTION}, author={Baynes, RE and Lyman, R and Anderson, KL and Brownie, CF}, year={1999}, month={Feb}, pages={177–180} }