Roger B.  Harvey

Dr. Roger B. Harvey

Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, College Station, TX 77845, USA

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2011 in Foodborne Pathogens and Disease
Verified
Journal Article
Closed access
Roger B.  HarveyRoger B. Harvey
Roger B. Harvey
KNKeri N. Norman
Keri N. Norman
KAKathleen Andrews
Kathleen Andrews
MHMichael E. Hume
Michael E. Hume
CSCharles M. Scanlan
Charles M. Scanlan
DNDavid J. Nisbet
David J. Nisbet
The incidence and severity of disease associated with toxigenic Clostridium difficile have increased in hospitals in North America from the emergence of newer, more virulent strains. Toxigenic C. difficile has been isolated from food animals and retail meat with potential implications of transfer to human beings. The objective of the present study was to determine the prevalence of toxigenic C. difficile in chickens and retail poultry meat in Texas. Seven C. difficile isolates were detected in fecal samples of 300 (2.3%) broiler chickens. Three cultivation procedures were evaluated for isolation of C. difficile from poultry meat and detected 1/32 (3.1%), 2/32 (6.2%), and 4/32 (12.5%) for the three procedures, respectively. Chicken and poultry meat isolates were characterized as toxinotype V and pulsed-field gel electrophoresis gel type-NAP7 or NAP7-variant. Susceptibilities to 11 antimicrobial agents in the current study suggested somewhat reduced resistance than reported for other meat or animal toxinotype V isolates.

6 July 2011 in Journal of Veterinary Diagnostic Investigation
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Journal Article
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Roger B.  HarveyRoger B. Harvey
Roger B. Harvey
KNKeri N. Norman
Keri N. Norman
KAKathleen Andrews
Kathleen Andrews
BNBo Norby
Bo Norby
MHMichael E. Hume
Michael E. Hume
HSHarvey Morgan Scott
Harvey Morgan Scott
The incidence and severity of disease associated with toxigenic Clostridium difficile have increased in hospitals in North America from the emergence of newer, more virulent strains. Toxigenic C. difficile has been isolated from food animals and retail meat with potential implications of transfer to human beings. The objective of the present study was to determine the prevalence of C. difficile in pork from sausage manufacturing plants and retail meat in Texas. Twenty-three C. difficile isolates were detected from 243 meat samples (9.5%) from 3 sausage-manufacturing plants and 5 retail meat outlets from 2004 to 2009. Twenty-two isolates were positive for toxins A, B, and binary toxin, and were characterized as toxinotype V, PFGE type-NAP7, or “NAP7-variant.” Susceptibilities to 11 antimicrobial agents in the current study were similar to those reported previously for toxinotype V isolates, although the results suggested somewhat reduced resistance than reported for other meat, animal, or human clinical toxinotype V isolates.

30 April 2014 in Food Additives & Contaminants: Part A
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Journal Article
Closed access
KNKeri N. Norman
Keri N. Norman
Roger B.  HarveyRoger B. Harvey
Roger B. Harvey
KAKathleen Andrews
Kathleen Andrews
MHMichael E. Hume
Michael E. Hume
Todd Riley CallawayTodd Riley Callaway
Todd Riley Callaway
DNDavid J. Nisbet
David J. Nisbet
The incidence and severity of disease associated with toxigenic Clostridium difficile have increased in hospitals in North America with the emergence of newer, more virulent strains. Toxigenic C. difficile has been isolated from food animals and retail meat with potential implications of transfer to humans. The objective of the present study was to investigate the prevalence of C. difficile in retail seafood from grocery stores in College Station, Texas. C. difficile was found in 4.5% (3/67) of shellfish and finfish samples. The positive samples included one each from fresh mussel, frozen salmon and frozen shrimp. The mussel and salmon isolates were characterized as toxinotype V and pulsed-field gel electrophoresis (PFGE) type-NAP7. The shrimp isolate was identified as toxinotype XII, but had an unknown PFGE type. Susceptibilities to 11 antimicrobial agents were identical for the mussel and salmon isolates and were sensitive to eight of 11 antimicrobials (including ampicillin) and intermediate to clindamycin. However, the shrimp isolate was resistant to clindamycin and ampicillin. This study demonstrates that seafood, like other food commodities, can be contaminated by C. difficile.


1 January 2016 in Journal of Food Protection
Verified
Journal Article
Closed access
GLG. Levent
G. Levent
Roger B.  HarveyRoger B. Harvey
Roger B. Harvey
GCG. Ciftcioglu
G. Ciftcioglu
RBR.C. Beier
R.C. Beier
KGK.J. Genovese
K.J. Genovese
DND.J. Nisbet
D.J. Nisbet
Although thymol is bactericidal against many pathogens in vitro, its in vivo effectiveness against pathogens in the lower gastrointestinal tract is limited because of its rapid absorption in the proximal gut. Thymol-β-D-glucopyranoside (β-thymol), a conjugated form of thymol, can deliver thymol to the lower gastrointestinal tract and has shown antibacterial effects. In the present study, we examined the in vitro effects of β-thymol on Salmonella enterica serovar Typhimurium (ST) and Escherichia coli K88 (K88). We inoculated one-half strength Mueller-Hinton broth with 5.8 ± 0.09 log CFU/ml novobiocin- and naladixic acid-resistant (NN) ST (NVSL 95-1776) and 5.1 ± 0.09 log CFU ml(-1) NN-resistant K88, with or without porcine feces (0.1% [wt/vol]) (fecal incubations). The resultant bacterial suspensions were distributed under N2 to triplicate sets of tubes to achieve initial concentrations of 0, 3, 6, and 12 mM for ST treatments and 0, 3, 12, and 30 mM for K88 treatments. Samples were incubated at 39°C and then plated onto NN-containing brilliant green agar and NN-containing MacConkey agar; ST and K88 CFU concentrations were determined via 10-fold dilutions, and viable cell counts were performed at 0, 6, and 24 h. No differences in ST CFU counts were observed in β-thymol-treated tubes without the added porcine feces (i.e., pure culture) at 6 or 24 h. However, in tubes that contained fecal incubations, ST CFU counts were reduced (P < 0.05) from controls at 6 h in tubes treated with 6 and 12 mM β-thymol, whereas in tubes treated with 3, 6, and 12 mM β-thymol the CFU counts were reduced (P < 0.05) at 24 h. No differences were observed in K88 CFU counts in pure culture or in fecal incubations at 6 h, but K88 CFU counts were reduced (P < 0.05) in both pure and fecal incubations at 24 h. The results from this study demonstrate that β-thymol, in the presence of fecal suspensions, has anti-Salmonella and anti-E. coli effects, suggesting a role of β-glycoside-hydrolyzing microbes for the release of bactericidal thymol from β-thymol.

22 August 2012 in Reproductive Biology and Endocrinology
Verified
Journal Article
Open access
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ISIvan Blagoje Stancic
Ivan Blagoje Stancic
DBDarko V Bošnjak
Darko V Bošnjak
IRIvan B Radović
Ivan B Radović
BSBlagoje L Stančić
Blagoje L Stančić
Roger B.  HarveyRoger B. Harvey
Roger B. Harvey
RARobin Anderson
Robin Anderson
Background: Prolonged pre-insemination anestrus (i.e. delayed puberty) is a major contributing factor for culling up to 30% of the replacement gilts at large breeding farm units in Vojvodina. It is imperative to determine if these gilts are acyclic (prepubertal) or cyclic, but just fail to exhibit behavioural estrus. Recent investigations demonstrate that treatment with equine chorionic gonadotropin (eCG) can increase the diestrous phase duration in sexually mature gilts. Based on these finding, the aim of the present studies was to determine the reproductive status of delayed puberty gilts following injection with eCG. Methods: Two experiments were conducted on a swine breeding farm in Vojvodina. In Exp. 1, 20 prepubertal (acyclic) gilts, and 120 sexually mature (cyclic) gilts were injected with a single injection of 400 IU eCG + 200 IU human chorionic gonadotropin (hCG) or with 1000 IU eCG (cyclic gilts), at d5, d11 or d17 after spontaneous estrus detection, to determine their ovarian reaction and induced estrus manifestation. In Exp. 2, sixty delayed puberty gilts (estrus not detected until 8 month of age, av. 258 days) were culled from breeding herd and slaughtered to determine their reproductive status based on ovarian anatomical features. The second group of gilts (n = 60) was treated with a single 1000 IU eCG injection to determine their reproductive status, based on the interval between eCG injection to estrus detection and duration. The data were analyzed by descriptive statistics, t-test, analysis of variance and Duncan’s test in the software package Statistics 10th. Results: Ovulations were induced in 90% of acyclic (sexually immature) and, on average, 93.3% of cyclic (sexually mature) gilts after the eCG injection. On average, 4 days after the eCG injection, estrus was detected in 85% of the treated acyclic (sexually immature) gilts and in 95% (19/20) of the cyclic (sexually mature) gilts, treated with eCG on day 17 after spontaneous estrus detection. The interval from eCG to induced estrus detection was prolonged (av. 25 days) in 95% (19/20) of the sexually mature gilts treated with eCG on day 5 and in 90% (18/20) of gilts treated on day 11 after spontaneous estrus detection (Exp. 1). Forty anestrous gilts reached cyclic pubertal ovarian activity. Estrus manifestation was detected in 56 gilts (93.3% of the total 60 treated prolonged anestrous gilts, av. 259 days of age), after a single 1000 IU eCG injection. Thirty-four gilts (60.7% of the total gilts in estrus) with prolonged eCG to estrus interval (av. 24.7 days) were considered spontaneously cyclic (sexually mature), but behaviourally anestrous before treatment. The remaining 22 (39.3% of the total gilts in estrus) were considered truly sexually immature (acyclic) before the treatment or were eCG injected in the late luteal or proestrous phase of spontaneous estrous cycle (Exp. 2). Conclusions: In 66.7% of the delayed puberty gilts, pre-ovulatory follicles (PoF), corpora hemorrhagica (CH), corpora lutea (CL), or corpora albicantia (CA) were found on the ovaries upon post mortem examination. These gilts were considered as sexually mature before slaughtering. In 60.7% of the delayed puberty gilts, behavioural estrus was detected an average of 24.7 days following eCG injections. These gilts were considered as eCG treated during the luteal phase (diestrus) of the spontaneous estrus cycle. Both findings suggest that delayed puberty gilts actually reached cyclic pubertal ovarian activity (sexual maturity) before culling from the breeding herd.