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François Malouin - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of a Rhodomyrtus tomentosa ethanolic extract for its therapeutic potential on Staphylococcus aureus infections using in vitro and in vivo models of mastitis
Veterinary Research, 2019Co-Authors: Auemphon Mordmuang, Eric Brouillette, Supayang Piyawan Voravuthikunchai, François MalouinAbstract:An ethanolic extract from Rhodomyrtus tomentosa leaves (RTL) was studied as a natural alternative to control Staphylococcus aureus , which is an important pathogen responsible for bovine mastitis. The minimal inhibitory concentrations (MICs) of the RTL extract and of rhodomyrtone, a pure compound isolated from the plant, were determined by a microdilution method. Rhodomyrtone and the RTL extract exhibited antibacterial activity against S. aureus , including its persistent phenotype (SCV: small-colony variant) and a biofilm hyperproducer strain, with MICs of 0.25–0.5 and 8–16 µg/mL, respectively. Time-kill kinetics showed a strong bactericidal activity for both the RTL extract- and rhodomyrtone-treated bacteria at 2 × MIC as early as 4 h post-exposure. An additive effect of the extract at 0.5 × MIC was observed in a combination with oxytetracycline or Pirlimycin against S. aureus by showing a 64- to 128-fold reduction in antibiotic MICs. Moreover, the RTL extract significantly decreased the number of intracellular SCVs inside bovine mammary epithelial cells. However, the extract or its combination with Pirlimycin only slightly improved the activity of Pirlimycin against the bacterial colonization of mouse mammary glands. In vitro MICs determined in the presence of casein indicated that the limited activity of the RTL extract in the murine model of mastitis could be linked to neutralization of active components by milk proteins. While the RTL extract showed interesting antibacterial properties in vitro, to be considered as an alternative to antibiotics in dairy farms, formulation studies are needed to cope with the observed reduction of activity in vivo.
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in vitro antibiotic susceptibility and biofilm production of staphylococcus aureus isolates recovered from bovine intramammary infections that persisted or not following extended therapies with cephapirin Pirlimycin or ceftiofur
Veterinary Research, 2017Co-Authors: Celine Ster, Valerie Lebeau, Julia Leclerc, Alexandre Fugere, François MalouinAbstract:Staphylococcus aureus intramammary infections (IMIs) have low cure rates using standard antibiotic treatment and increasing the duration of treatment usually improves therapeutic success. Chronic IMIs are thought to be caused by bacteria presenting a specific virulence phenotype that includes the capacity to produce greater amounts of biofilm. In this study, antibiotic susceptibility and biofilm production by S. aureus isolates recovered from IMIs that were cured or not following an extended therapy with cephapirin, Pirlimycin or ceftiofur for 5, 8 and 8 days, respectively, were compared. An isolate was confirmed as from a persistent case (not cured) if the same S. aureus strain was isolated before and after treatment as revealed by the same VNTR profile (variable number of tandem repeats detected by multiplex PCR). The antibiotic minimal inhibitory concentrations (MICs) were determined for these isolates as well as the capacity of the isolates to produce biofilm. Isolates from persistent cases after extended therapy with cephapirin or ceftiofur had higher MICs for these drugs compared to isolates from non-persistent cases (p < 0.05) even though the antibiotic susceptibility breakpoints were not exceeded. Isolates of the ceftiofur study significantly increased their biofilm production in presence of a sub-MIC of ceftiofur (p < 0.05), whereas isolates from the Pirlimycin group produced significantly less biofilm in presence of a sub-MIC of Pirlimycin (p < 0.001). Relative antibiotic susceptibility of the isolates as well as biofilm production may play a role in the failure of extended therapies. On the other hand, some antibiotics may counteract biofilm formation and improve cure rates.
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In vitro antibiotic susceptibility and biofilm production of Staphylococcus aureus isolates recovered from bovine intramammary infections that persisted or not following extended therapies with cephapirin, Pirlimycin or ceftiofur
Veterinary Research, 2017Co-Authors: Celine Ster, Valerie Lebeau, Julia Leclerc, Alexandre Fugere, François MalouinAbstract:Staphylococcus aureus intramammary infections (IMIs) have low cure rates using standard antibiotic treatment and increasing the duration of treatment usually improves therapeutic success. Chronic IMIs are thought to be caused by bacteria presenting a specific virulence phenotype that includes the capacity to produce greater amounts of biofilm. In this study, antibiotic susceptibility and biofilm production by S. aureus isolates recovered from IMIs that were cured or not following an extended therapy with cephapirin, Pirlimycin or ceftiofur for 5, 8 and 8 days, respectively, were compared. An isolate was confirmed as from a persistent case (not cured) if the same S. aureus strain was isolated before and after treatment as revealed by the same VNTR profile (variable number of tandem repeats detected by multiplex PCR). The antibiotic minimal inhibitory concentrations (MICs) were determined for these isolates as well as the capacity of the isolates to produce biofilm. Isolates from persistent cases after extended therapy with cephapirin or ceftiofur had higher MICs for these drugs compared to isolates from non-persistent cases ( p
K F Knowlton - One of the best experts on this subject based on the ideXlab platform.
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fate of Pirlimycin and antibiotic resistance genes in dairy manure slurries in response to temperature and ph adjustment
Science of The Total Environment, 2020Co-Authors: Meng M Li, K F Knowlton, Amy Pruden, C L Teets, Pang DuAbstract:Abstract Quantifying the fate of antibiotics and antibiotic resistance genes (ARGs) in response to physicochemical factors during storage of manure slurries will aid in efforts to reduce the spread of resistance when manure is land-applied. The objectives of this study were to determine the effects of temperature (10, 35, and 55 °C) and initial pH (5, 7, 9, and 12) on the removal of Pirlimycin and prevalence of ARGs during storage of dairy manure slurries. We collected and homogenized feces and urine from five lactating dairy cows treated with Pirlimycin and prepared slurries by mixing manure and sterile water. Aliquots (200 mL) of slurry were transferred and incubated in 400 mL glass beakers under different temperatures (10, 35, and 55 °C) or initial pH (5, 7, 9, and 12). Pirlimycin concentration and abundances of 16S rRNA, mefA, tet(W), and cfxA as indicators of total bacteria and ARGs corresponding to macrolide, tetracycline, and β-lactam resistance, respectively, were analyzed during manure incubation. The thermophilic environment (55 °C) increased the deconjugation and removal of Pirlimycin, while the acidic shock at pH 5 increased deconjugation but inhibited removal of Pirlimycin, suggesting that the chemical stability of Pirlimycin could be affected by temperature and pH. The thermophilic environment decreased mefA relative abundance on day 7 and 28 (P = 0.02 and 0.04), which indicates that the bacteria that encoded mefA gene were not thermotolerant. Although mefA relative abundance was greater at the pH 9 shock than the rest of pH treatments on day 7 (P = 0.04), no significant pH effect was observed on day 28. The tet(W) abundance under initial pH 12 shock was less than other pH shocks on day 28 (P = 0.01), while no temperature effect was observed on day 28. There was no significant temperature and initial pH effect on cfxA abundance at any time point during incubation, implying that the bacteria that carrying cfxA gene are relatively insensitive to these environmental factors. Overall, directly raising temperature and pH can facilitate Pirlimycin removal and decrease mefA and tet(W) relative abundances during storage of manure slurries.
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manure injection affects the fate of Pirlimycin in surface runoff and soil
Journal of Environmental Quality, 2016Co-Authors: Stephanie B Kulesza, Rory O Maguire, Julia Cushman, K F KnowltonAbstract:Antibiotics used in animal agriculture are of increasing environmental concern due to the potential for increased antibiotic resistance after land application of manure. Manure application technology may affect the environmental behavior of these antibiotics. Therefore, rainfall simulations were conducted on plots receiving three manure treatments (surface application, subsurface injection, and no manure control) to determine the fate and transport of Pirlimycin, an antibiotic commonly used in dairy production. Rainfall simulations were conducted immediately and 7 d after application of dairy manure spiked with 128 ng g−1 (wet weight) Pirlimycin. Soil samples were collected from all plots at two depths (0–5 and 5–20 cm). For injection plots, soil was collected from injection slits and between slits. Pirlimycin concentrations were higher in soil within the injection slits compared with surface application plots at 0 and 7 d. Pirlimycin concentrations in the 0- to 5-cm depth decreased by 30, 55, and 87% in the injection slit, between injection slits, and surface application plots 7 d after application. Pirlimycin concentrations were 106 ng g−1 in sediment and 4.67 ng mL−1 in water from the surface application plots, which were 21 and 32 times that of the injection plots, respectively. After 7 d, Pirlimycin levels in runoff sediment and water decreased 80 to 98%. Surface application resulted in six and three times higher Pirlimycin concentrations in water and sediment than injection. These results indicate that Pirlimycin is most susceptible to loss immediately after manure application. Thus, injection could be considered a best management practice to prevent loss of antibiotics in surface runoff.
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method development and validation solid phase extraction ultra performance liquid chromatography tandem mass spectrometry quantification of Pirlimycin in bovine feces and urine
Journal of AOAC International, 2014Co-Authors: K F Knowlton, C ShangAbstract:Pirlimycin, a lincosamide antibiotic, is one of the most commonly used antibiotics for the treatment of mastitis in dairy cows. Assessment of Pirlimycin loading to the environment via fecal and urinary excretion is critical to develop efficient management strategies to reduce environmental pollution by the livestock industry. Therefore, the aim of this study was to develop and validate an analytical method to identify and quantify Pirlimycin in bovine feces and urine. Samples were extracted with methanol– phosphate buffer and cleaned up by SPE before analysis for Pirlimycin using UPLC-MS/MS. This method was sensitive (LOQ 1.47 ng/g wet feces, 0.90 ng/mL urine), accurate (recovery, 80–108%), and precise (repeatability, 2.3–13%; reproducibility, 2.3–14%) for both bovine feces and urine. With the application of this method to samples collected in the first 10 h and then every 24 h for 120 h following intramammary dosing (50 mg/cow; n = 3 cows), Pirlimycin was detected at 40.5–287 ng/g and 46.1–254 ng/mL in feces and urine, respectively. This robust, sensitive, and accurate method can be used to assess the fate and environmental impact of antibiotics used on farms.
Amy Pruden - One of the best experts on this subject based on the ideXlab platform.
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fate of Pirlimycin and antibiotic resistance genes in dairy manure slurries in response to temperature and ph adjustment
Science of The Total Environment, 2020Co-Authors: Meng M Li, K F Knowlton, Amy Pruden, C L Teets, Pang DuAbstract:Abstract Quantifying the fate of antibiotics and antibiotic resistance genes (ARGs) in response to physicochemical factors during storage of manure slurries will aid in efforts to reduce the spread of resistance when manure is land-applied. The objectives of this study were to determine the effects of temperature (10, 35, and 55 °C) and initial pH (5, 7, 9, and 12) on the removal of Pirlimycin and prevalence of ARGs during storage of dairy manure slurries. We collected and homogenized feces and urine from five lactating dairy cows treated with Pirlimycin and prepared slurries by mixing manure and sterile water. Aliquots (200 mL) of slurry were transferred and incubated in 400 mL glass beakers under different temperatures (10, 35, and 55 °C) or initial pH (5, 7, 9, and 12). Pirlimycin concentration and abundances of 16S rRNA, mefA, tet(W), and cfxA as indicators of total bacteria and ARGs corresponding to macrolide, tetracycline, and β-lactam resistance, respectively, were analyzed during manure incubation. The thermophilic environment (55 °C) increased the deconjugation and removal of Pirlimycin, while the acidic shock at pH 5 increased deconjugation but inhibited removal of Pirlimycin, suggesting that the chemical stability of Pirlimycin could be affected by temperature and pH. The thermophilic environment decreased mefA relative abundance on day 7 and 28 (P = 0.02 and 0.04), which indicates that the bacteria that encoded mefA gene were not thermotolerant. Although mefA relative abundance was greater at the pH 9 shock than the rest of pH treatments on day 7 (P = 0.04), no significant pH effect was observed on day 28. The tet(W) abundance under initial pH 12 shock was less than other pH shocks on day 28 (P = 0.01), while no temperature effect was observed on day 28. There was no significant temperature and initial pH effect on cfxA abundance at any time point during incubation, implying that the bacteria that carrying cfxA gene are relatively insensitive to these environmental factors. Overall, directly raising temperature and pH can facilitate Pirlimycin removal and decrease mefA and tet(W) relative abundances during storage of manure slurries.
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The impacts of feeding milk with antibiotics on the fecal microbiome and antibiotic resistance genes in dairy calves
Canadian Journal of Animal Science, 2020Co-Authors: Xin Feng, Katharine F. Knowlton, Heather Littier, Emily Garner, Amy PrudenAbstract:The effects of ingestion of antibiotics on the microbiome of the young calf are not well understood. The objective of this study was to evaluate the effect of feeding milk containing Pirlimycin on ...
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Fecal Indicator Bacteria and Antibiotic Resistance Genes in Storm Runoff from Dairy Manure and Compost-Amended Vegetable Plots.
Journal of Environmental Quality, 2019Co-Authors: Kyle Jacobs, Lauren Wind, Leigh-anne Krometis, W. Cully Hession, Amy PrudenAbstract:Given the presence of antibiotics and resistant bacteria in livestock manures, it is important to identify the key pathways by which land-applied manure-derived soil amendments potentially spread resistance. The goal of this field-scale study was to identify the effects of different types of soil amendments (raw manure from cows treated with cephapirin and Pirlimycin, compost from antibiotic-treated or antibiotic-free cows, or chemical fertilizer only) and crop type (lettuce [Lactuca sativa L.] or radish [Raphanus sativus L.]) on the transport of two antibiotic resistance genes (ARGs; sul1 and ermB) via storm runoff from six naturally occurring storms. Concurrent quantification of sediment and fecal indicator bacteria (FIB; Escherichia coli and enterococci) in runoff permitted comparison to traditional agricultural water quality targets that may be driving factors of ARG presence. Storm characteristics (total rainfall volume, storm duration, etc.) significantly influenced FIB concentration (two-way ANOVA, p < 0.05), although both effects from individual storm events (Kruskal–Wallis, p < 0.05) and vegetative cover influenced sediment levels. Composted and raw manure-amended plots both yielded significantly higher sul1 and ermB levels in runoff for early storms, at least 8 wk following initial planting, relative to fertilizer-only or unamended barren plots. There was no significant difference between sul1 or ermB levels in runoff from plots treated with compost derived from antibiotic-treated versus antibiotic-free dairy cattle. Our findings indicate that agricultural fields receiving manure-derived amendments release higher quantities of these two “indicator” ARGs in runoff, particularly during the early stages of the growing season, and that composting did not reduce effects of ARG loading in runoff.
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Effect of antibiotic use and composting on antibiotic resistance gene abundance and resistome risks of soils receiving manure-derived amendments.
Environment International, 2019Co-Authors: Chaoqui Chen, Pang Du, Christine A. Pankow, Min Oh, Lenwood S. Heath, Liqing Zhang, Amy PrudenAbstract:: Manure-derived amendments are commonly applied to soil, raising questions about whether antibiotic use in livestock could influence the soil resistome (collective antibiotic resistance genes (ARGs)) and ultimately contribute to the spread of antibiotic resistance to humans during food production. Here, we examined the metagenomes of soils amended with raw or composted manure generated from dairy cows administered Pirlimycin and cephapirin (antibiotic) or no antibiotics (control) relative to unamended soils. Initial amendment (Day 1) with manure or compost significantly increased the diversity (richness) of ARGs in soils (p
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fate of Pirlimycin and antibiotic resistant fecal coliforms in field plots amended with dairy manure or compost during vegetable cultivation
Journal of Environmental Quality, 2018Co-Authors: Lauren Wind, Leigh-anne Krometis, Kyle Jacobs, Pang Du, Chaoqi Chen, Cully W Hession, Amy PrudenAbstract:: Identification of agricultural practices that mitigate the environmental dissemination of antibiotics is a key need in reducing the prevalence of antibiotic-resistant bacteria of human health concern. Here, we aimed to compare the effects of crop (lettuce [ L.] or radish [ L.]), soil amendment type (inorganic fertilizer, raw dairy manure, composted dairy manure, or no amendment), and prior antibiotic use history (no antibiotics during previous lactation cycles vs. manure mixed from cows administered Pirlimycin or cephapirin) of manure-derived amendments on the incidence of culturable antibiotic-resistant fecal coliforms in agricultural soils through a controlled field-plot experiment. Antibiotic-resistant culturable fecal coliforms were recoverable from soils across all treatments immediately after application, although persistence throughout the experiment varied by antibiotic class and time. The magnitude of observed coliform counts differed by soil amendment type. Compost-amended soils had the highest levels of cephalosporin-resistant fecal coliforms, regardless of whether the cows from which the manure was derived were administered antibiotics. Samples from control plots or those treated with inorganic fertilizer trended toward lower counts of resistant coliforms, although these differences were not statistically significant. No statistical differences were observed between soils that grew leafy (lettuce) versus rooted (radish) crops. Only Pirlimycin was detectable past amendment application in raw manure-amended soils, dissipating 12 to 25% by Day 28. Consequently, no quantifiable correlations between coliform count and antibiotic magnitude could be identified. This study demonstrates that antibiotic-resistant fecal coliforms can become elevated in soils receiving manure-derived amendments, but that a variety of factors likely contribute to their long-term persistence under typical field conditions.
H. Moorehead - One of the best experts on this subject based on the ideXlab platform.
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Efficacy of extended Pirlimycin therapy for treatment of experimentally induced Streptococcus uberis intramammary infections in lactating dairy cattle.
Veterinary Therapeutics, 2020Co-Authors: Stephen P. Oliver, Raul A. Almeida, Barbara E. Gillespie, S. J. Ivey, H. Moorehead, Phillip Lunn, H.h. Dowlen, D.l. Johnson, Ken C LamarAbstract:: Streptococcus uberis is an important cause of mastitis in dairy cows throughout the world, particularly during the dry period, around the time of calving, and during early lactation. Strategies for controlling S. uberis mastitis have not received adequate research attention and are therefore poorly defined and inadequate. Objectives of the present study were to evaluate the efficacy of extended therapy regimens with Pirlimycin for treatment of experimentally induced S. uberis intramammary infections in lactating dairy cows during early lactation and to evaluate the usefulness of the S. uberis experimental infection model for evaluating antimicrobial efficacy in dairy cows. The efficacy of extended Pirlimycin intramammary therapy regimens was investigated in 103 mammary glands of 68 dairy cows that became infected following experimental challenge with S. uberis during early lactation. Cows infected with S. uberis in one or both experimentally challenged mammary glands were randomly allocated to three groups, representing three different treatment regimens with Pirlimycin, including 2-day (n = 21 cows, 31 mammary quarters), 5-day (n = 21 cows, 32 quarters), and 8-day (n = 26 cows, 40 quarters). For all groups, Pirlimycin was administered at a rate of 50 mg of Pirlimycin hydrochloride via intramammary infusion. A cure was defined as an experimentally infected mammary gland that was treated with Pirlimycin and was bacteriologically negative for the presence of S. uberis at 7, 14, 21, and 28 days after treatment. Experimental S. uberis intramammary infections were eliminated in 58.1% of the infected quarters treated with the Pirlimycin 2-day regimen, 68.8% for the 5-day regimen, and 80.0% for the 8-day regimen. Significant differences (P
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intramammary infections in heifers during early lactation following intramammary infusion of Pirlimycin hydrochloride or penicillin novobiocin at the first milking after parturition
Journal of Dairy Research, 2007Co-Authors: Stephen P. Oliver, H. Moorehead, H.h. Dowlen, D.l. Johnson, B E Gillespie, M J Lewis, K C Lamar, Susan I Headrick, John W HallbergAbstract:A study was conducted to determine whether intramammary antibiotic treatment of heifer mammary glands following the first milking after calving was effective for reducing the percentage of mammary quarters infected during early lactation. Jersey and Holstein heifers from two research herds were assigned to one of three treatment groups: (1) no intramammary infusion following the first milking after parturition, (2) intramammary infusion of all quarters with Pirlimycin hydrochloride following the first milking after parturition and (3) intramammary infusion of all quarters with novobiocin sodium plus penicillin G procaine following the first milking after parturition. Almost 93% of Jersey heifers (40/43) and 73·1% of quarters (125/171) were infected at the first milking. Almost 77% of quarters (33/43) were cured following treatment with Pirlimycin, 61·8% (21/34) were cured following treatment with penicillin-novobiocin and 39·6% (19/48) of infections were eliminated spontaneously in the untreated control group. Significantly fewer infections were observed in Pirlimycin or penicillin-novobiocin treated mammary glands of Jersey heifers during early lactation than in untreated control mammary glands. Almost 89% of Holstein heifers (32/36) and 52·8% of quarters (76/144) were infected at the first milking. About 57% (12/21) of quarters were cured following treatment with Pirlimycin, 41·4% (12/29) were cured following treatment with penicillin-novobiocin and 23·1% (6/26) of infections were eliminated spontaneously in the untreated negative control group. Significantly fewer infections were observed in Pirlimycin treated mammary glands of Holstein heifers during early lactation than in untreated control mammary glands. However, no significant differences were observed following penicillin-novobiocin treatment of Holstein heifers after the first milking of lactation compared with untreated control quarters. Coagulase-negative staphylococci, Streptococcus uberis and Streptococcus dysgalactiae subsp dysgalactiae were isolated most frequently in heifers from both herds.
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influence of prepartum Pirlimycin hydrochloride or penicillin novobiocin therapy on mastitis in heifers during early lactation
Journal of Dairy Science, 2004Co-Authors: S P Oliver, S. J. Ivey, H. Moorehead, H.h. Dowlen, D.l. Johnson, B E Gillespie, M J Lewis, K C Lamar, S T Chester, J W HallbergAbstract:A study was conducted in 2 dairy research herds to determine whether prepartum therapy of heifer mammary glands with penicillin-novobiocin or Pirlimycin hydrochloride was effective for reducing the percentage of heifers and mammary quarters infected with mastitis pathogens during early lactation. Almost 96% of Jersey heifers (67 of 70) and 71.3% of quarters (199 of 279) were infected 14 d before expected calving. Of the quarters infected at 14 d before expected parturition, 75% (54 of 72) were uninfected following treatment with penicillin-novobiocin; 87% (61 of 70) were uninfected following treatment with Pirlimycin, and 56% (32 of 57) were uninfected in the untreated negative control group. The majority of intramammary infections in Jersey heifers were due to coagulase-negative staphylococci (61%), Streptococcus species, primarily Streptococcus uberis (19%), and Staphylococcus aureus (8%). Almost 73% of Holstein heifers (40 of 55) and 34.3% of mammary quarters (73 of 213) were infected 14 d before expected calving. Of the quarters infected at 14 d before expected parturition, 76% (19 of 25) were uninfected following treatment with penicillin-novobiocin; 59% (17 of 29) were uninfected following treatment with Pirlimycin, and 26% (5 of 19) were uninfected in the untreated negative control group. The majority of intramammary infections in Holstein heifers were due to coagulase-negative staphylococci (44%) and Staph. aureus (30%). In both herds, the bacteriological cure rate was significantly higher in heifer mammary glands treated with penicillin-novobiocin or Pirlimycin hydrochloride than in untreated controls. Prepartum therapy of heifer mammary glands with penicillin-novobiocin or Pirlimycin hydrochloride significantly reduced the percentage of heifers and quarters infected with mastitis pathogens during early lactation.
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efficacy of extended Pirlimycin therapy for treatment of experimentally induced streptococcus uberis intramammary infections in lactating dairy cattle
Veterinary Therapeutics, 2003Co-Authors: Stephen P. Oliver, Raul A. Almeida, Barbara E. Gillespie, S. J. Ivey, H. Moorehead, Phillip Lunn, H.h. Dowlen, D.l. Johnson, Ken C LamarAbstract:: Streptococcus uberis is an important cause of mastitis in dairy cows throughout the world, particularly during the dry period, around the time of calving, and during early lactation. Strategies for controlling S. uberis mastitis have not received adequate research attention and are therefore poorly defined and inadequate. Objectives of the present study were to evaluate the efficacy of extended therapy regimens with Pirlimycin for treatment of experimentally induced S. uberis intramammary infections in lactating dairy cows during early lactation and to evaluate the usefulness of the S. uberis experimental infection model for evaluating antimicrobial efficacy in dairy cows. The efficacy of extended Pirlimycin intramammary therapy regimens was investigated in 103 mammary glands of 68 dairy cows that became infected following experimental challenge with S. uberis during early lactation. Cows infected with S. uberis in one or both experimentally challenged mammary glands were randomly allocated to three groups, representing three different treatment regimens with Pirlimycin, including 2-day (n = 21 cows, 31 mammary quarters), 5-day (n = 21 cows, 32 quarters), and 8-day (n = 26 cows, 40 quarters). For all groups, Pirlimycin was administered at a rate of 50 mg of Pirlimycin hydrochloride via intramammary infusion. A cure was defined as an experimentally infected mammary gland that was treated with Pirlimycin and was bacteriologically negative for the presence of S. uberis at 7, 14, 21, and 28 days after treatment. Experimental S. uberis intramammary infections were eliminated in 58.1% of the infected quarters treated with the Pirlimycin 2-day regimen, 68.8% for the 5-day regimen, and 80.0% for the 8-day regimen. Significant differences (P <.05) in efficacy were observed between the 2-day and 8-day treatment regimens. The number of somatic cells in milk decreased significantly following therapy in quarters for which treatment was successful in eliminating S. uberis. However, there was no evidence to suggest that extended therapy with Pirlimycin resulted in a greater reduction in somatic cell counts in milk than the 2-day treatment. The S. uberis experimental infection model was a rapid and effective means of evaluating antimicrobial efficacy during early lactation at a time when mammary glands are highly susceptible to S. uberis intramammary infection.
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efficacy of extended Pirlimycin hydrochloride therapy for treatment of environmental streptococcus spp and staphylococcus aureus intramammary infections in lactating dairy cows
Veterinary Therapeutics, 2002Co-Authors: B E Gillespie, S. J. Ivey, H. Moorehead, Phillip Lunn, H.h. Dowlen, D.l. Johnson, M J Lewis, K C Lamar, J W Hallberg, S T ChesterAbstract:: Fifty-one chronically infected lactating dairy cows were used to evaluate the efficacy of extended Pirlimycin therapy regimens for treatment of intramammary infections by environmental Streptococcus spp and Staphylococcus aureus. Cows (n = 47) with one or more infected mammary quarters were blocked by parity and randomly allocated to one of three groups for treatment with Pirlimycin (50 mg/mammary quarter) as follows: one treatment per day for 2 days (n = 36 infected mammary quarters); one treatment per day for 5 days (n = 36 infected mammary quarters); and one treatment per day for 8 days (n = 20 infected mammary quarters). Four cows with nine infected mammary quarters were included as untreated controls. Milk samples from each mammary quarter were collected 7 days before treatment, immediately before treatment, and weekly for 4 weeks after the final treatment for microbiological evaluation. A bacteriologic cure was defined as a treated, infected quarter that was bacteriologically negative for the presence of previously identified bacteria at weekly intervals after treatment. Efficacy of Pirlimycin therapy against intramammary infections caused by environmental Streptococcus spp and S. aureus was 44.4%, 61.1%, and 95.0% for the 2-, 5-, and 8-day treatment regimens, respectively. None of the infections in the untreated control quarters was cured. Significant differences in efficacy were detected between all Pirlimycin groups and the untreated control group, between the 8- and 2-day treatment regimens, and between the 8-day and 5-day treatment regimens (P < or = .05). Results of this study indicate that extended Pirlimycin therapy was effective in eliminating intramammary infections caused by environmental streptococci and S. aureus in lactating dairy cows.
H.h. Dowlen - One of the best experts on this subject based on the ideXlab platform.
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Efficacy of extended Pirlimycin therapy for treatment of experimentally induced Streptococcus uberis intramammary infections in lactating dairy cattle.
Veterinary Therapeutics, 2020Co-Authors: Stephen P. Oliver, Raul A. Almeida, Barbara E. Gillespie, S. J. Ivey, H. Moorehead, Phillip Lunn, H.h. Dowlen, D.l. Johnson, Ken C LamarAbstract:: Streptococcus uberis is an important cause of mastitis in dairy cows throughout the world, particularly during the dry period, around the time of calving, and during early lactation. Strategies for controlling S. uberis mastitis have not received adequate research attention and are therefore poorly defined and inadequate. Objectives of the present study were to evaluate the efficacy of extended therapy regimens with Pirlimycin for treatment of experimentally induced S. uberis intramammary infections in lactating dairy cows during early lactation and to evaluate the usefulness of the S. uberis experimental infection model for evaluating antimicrobial efficacy in dairy cows. The efficacy of extended Pirlimycin intramammary therapy regimens was investigated in 103 mammary glands of 68 dairy cows that became infected following experimental challenge with S. uberis during early lactation. Cows infected with S. uberis in one or both experimentally challenged mammary glands were randomly allocated to three groups, representing three different treatment regimens with Pirlimycin, including 2-day (n = 21 cows, 31 mammary quarters), 5-day (n = 21 cows, 32 quarters), and 8-day (n = 26 cows, 40 quarters). For all groups, Pirlimycin was administered at a rate of 50 mg of Pirlimycin hydrochloride via intramammary infusion. A cure was defined as an experimentally infected mammary gland that was treated with Pirlimycin and was bacteriologically negative for the presence of S. uberis at 7, 14, 21, and 28 days after treatment. Experimental S. uberis intramammary infections were eliminated in 58.1% of the infected quarters treated with the Pirlimycin 2-day regimen, 68.8% for the 5-day regimen, and 80.0% for the 8-day regimen. Significant differences (P
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intramammary infections in heifers during early lactation following intramammary infusion of Pirlimycin hydrochloride or penicillin novobiocin at the first milking after parturition
Journal of Dairy Research, 2007Co-Authors: Stephen P. Oliver, H. Moorehead, H.h. Dowlen, D.l. Johnson, B E Gillespie, M J Lewis, K C Lamar, Susan I Headrick, John W HallbergAbstract:A study was conducted to determine whether intramammary antibiotic treatment of heifer mammary glands following the first milking after calving was effective for reducing the percentage of mammary quarters infected during early lactation. Jersey and Holstein heifers from two research herds were assigned to one of three treatment groups: (1) no intramammary infusion following the first milking after parturition, (2) intramammary infusion of all quarters with Pirlimycin hydrochloride following the first milking after parturition and (3) intramammary infusion of all quarters with novobiocin sodium plus penicillin G procaine following the first milking after parturition. Almost 93% of Jersey heifers (40/43) and 73·1% of quarters (125/171) were infected at the first milking. Almost 77% of quarters (33/43) were cured following treatment with Pirlimycin, 61·8% (21/34) were cured following treatment with penicillin-novobiocin and 39·6% (19/48) of infections were eliminated spontaneously in the untreated control group. Significantly fewer infections were observed in Pirlimycin or penicillin-novobiocin treated mammary glands of Jersey heifers during early lactation than in untreated control mammary glands. Almost 89% of Holstein heifers (32/36) and 52·8% of quarters (76/144) were infected at the first milking. About 57% (12/21) of quarters were cured following treatment with Pirlimycin, 41·4% (12/29) were cured following treatment with penicillin-novobiocin and 23·1% (6/26) of infections were eliminated spontaneously in the untreated negative control group. Significantly fewer infections were observed in Pirlimycin treated mammary glands of Holstein heifers during early lactation than in untreated control mammary glands. However, no significant differences were observed following penicillin-novobiocin treatment of Holstein heifers after the first milking of lactation compared with untreated control quarters. Coagulase-negative staphylococci, Streptococcus uberis and Streptococcus dysgalactiae subsp dysgalactiae were isolated most frequently in heifers from both herds.
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influence of prepartum Pirlimycin hydrochloride or penicillin novobiocin therapy on mastitis in heifers during early lactation
Journal of Dairy Science, 2004Co-Authors: S P Oliver, S. J. Ivey, H. Moorehead, H.h. Dowlen, D.l. Johnson, B E Gillespie, M J Lewis, K C Lamar, S T Chester, J W HallbergAbstract:A study was conducted in 2 dairy research herds to determine whether prepartum therapy of heifer mammary glands with penicillin-novobiocin or Pirlimycin hydrochloride was effective for reducing the percentage of heifers and mammary quarters infected with mastitis pathogens during early lactation. Almost 96% of Jersey heifers (67 of 70) and 71.3% of quarters (199 of 279) were infected 14 d before expected calving. Of the quarters infected at 14 d before expected parturition, 75% (54 of 72) were uninfected following treatment with penicillin-novobiocin; 87% (61 of 70) were uninfected following treatment with Pirlimycin, and 56% (32 of 57) were uninfected in the untreated negative control group. The majority of intramammary infections in Jersey heifers were due to coagulase-negative staphylococci (61%), Streptococcus species, primarily Streptococcus uberis (19%), and Staphylococcus aureus (8%). Almost 73% of Holstein heifers (40 of 55) and 34.3% of mammary quarters (73 of 213) were infected 14 d before expected calving. Of the quarters infected at 14 d before expected parturition, 76% (19 of 25) were uninfected following treatment with penicillin-novobiocin; 59% (17 of 29) were uninfected following treatment with Pirlimycin, and 26% (5 of 19) were uninfected in the untreated negative control group. The majority of intramammary infections in Holstein heifers were due to coagulase-negative staphylococci (44%) and Staph. aureus (30%). In both herds, the bacteriological cure rate was significantly higher in heifer mammary glands treated with penicillin-novobiocin or Pirlimycin hydrochloride than in untreated controls. Prepartum therapy of heifer mammary glands with penicillin-novobiocin or Pirlimycin hydrochloride significantly reduced the percentage of heifers and quarters infected with mastitis pathogens during early lactation.
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efficacy of extended Pirlimycin therapy for treatment of experimentally induced streptococcus uberis intramammary infections in lactating dairy cattle
Veterinary Therapeutics, 2003Co-Authors: Stephen P. Oliver, Raul A. Almeida, Barbara E. Gillespie, S. J. Ivey, H. Moorehead, Phillip Lunn, H.h. Dowlen, D.l. Johnson, Ken C LamarAbstract:: Streptococcus uberis is an important cause of mastitis in dairy cows throughout the world, particularly during the dry period, around the time of calving, and during early lactation. Strategies for controlling S. uberis mastitis have not received adequate research attention and are therefore poorly defined and inadequate. Objectives of the present study were to evaluate the efficacy of extended therapy regimens with Pirlimycin for treatment of experimentally induced S. uberis intramammary infections in lactating dairy cows during early lactation and to evaluate the usefulness of the S. uberis experimental infection model for evaluating antimicrobial efficacy in dairy cows. The efficacy of extended Pirlimycin intramammary therapy regimens was investigated in 103 mammary glands of 68 dairy cows that became infected following experimental challenge with S. uberis during early lactation. Cows infected with S. uberis in one or both experimentally challenged mammary glands were randomly allocated to three groups, representing three different treatment regimens with Pirlimycin, including 2-day (n = 21 cows, 31 mammary quarters), 5-day (n = 21 cows, 32 quarters), and 8-day (n = 26 cows, 40 quarters). For all groups, Pirlimycin was administered at a rate of 50 mg of Pirlimycin hydrochloride via intramammary infusion. A cure was defined as an experimentally infected mammary gland that was treated with Pirlimycin and was bacteriologically negative for the presence of S. uberis at 7, 14, 21, and 28 days after treatment. Experimental S. uberis intramammary infections were eliminated in 58.1% of the infected quarters treated with the Pirlimycin 2-day regimen, 68.8% for the 5-day regimen, and 80.0% for the 8-day regimen. Significant differences (P <.05) in efficacy were observed between the 2-day and 8-day treatment regimens. The number of somatic cells in milk decreased significantly following therapy in quarters for which treatment was successful in eliminating S. uberis. However, there was no evidence to suggest that extended therapy with Pirlimycin resulted in a greater reduction in somatic cell counts in milk than the 2-day treatment. The S. uberis experimental infection model was a rapid and effective means of evaluating antimicrobial efficacy during early lactation at a time when mammary glands are highly susceptible to S. uberis intramammary infection.
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efficacy of extended Pirlimycin hydrochloride therapy for treatment of environmental streptococcus spp and staphylococcus aureus intramammary infections in lactating dairy cows
Veterinary Therapeutics, 2002Co-Authors: B E Gillespie, S. J. Ivey, H. Moorehead, Phillip Lunn, H.h. Dowlen, D.l. Johnson, M J Lewis, K C Lamar, J W Hallberg, S T ChesterAbstract:: Fifty-one chronically infected lactating dairy cows were used to evaluate the efficacy of extended Pirlimycin therapy regimens for treatment of intramammary infections by environmental Streptococcus spp and Staphylococcus aureus. Cows (n = 47) with one or more infected mammary quarters were blocked by parity and randomly allocated to one of three groups for treatment with Pirlimycin (50 mg/mammary quarter) as follows: one treatment per day for 2 days (n = 36 infected mammary quarters); one treatment per day for 5 days (n = 36 infected mammary quarters); and one treatment per day for 8 days (n = 20 infected mammary quarters). Four cows with nine infected mammary quarters were included as untreated controls. Milk samples from each mammary quarter were collected 7 days before treatment, immediately before treatment, and weekly for 4 weeks after the final treatment for microbiological evaluation. A bacteriologic cure was defined as a treated, infected quarter that was bacteriologically negative for the presence of previously identified bacteria at weekly intervals after treatment. Efficacy of Pirlimycin therapy against intramammary infections caused by environmental Streptococcus spp and S. aureus was 44.4%, 61.1%, and 95.0% for the 2-, 5-, and 8-day treatment regimens, respectively. None of the infections in the untreated control quarters was cured. Significant differences in efficacy were detected between all Pirlimycin groups and the untreated control group, between the 8- and 2-day treatment regimens, and between the 8-day and 5-day treatment regimens (P < or = .05). Results of this study indicate that extended Pirlimycin therapy was effective in eliminating intramammary infections caused by environmental streptococci and S. aureus in lactating dairy cows.