{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T21:43:03Z","timestamp":1777930983834,"version":"3.51.4"},"reference-count":23,"publisher":"SAGE Publications","issue":"4","license":[{"start":{"date-parts":[[1989,10,1]],"date-time":"1989-10-01T00:00:00Z","timestamp":623203200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J VET Diagn Invest"],"published-print":{"date-parts":[[1989,10]]},"abstract":"<jats:p>The effects of combining erythromycin (Ery) with oxytetracycline (Oxy) or spectinomycin (Sp) on Pasteurella haemolytica were evaluated in vitro using the chessboard (checkerboard) technique. These combinations were selected because all are drugs widely used in bovine respiratory disease treatment, and they represent possible sequential or complementary mechanisms of action. Using the recommended breakpoints of &gt;4 \u03bcg\/ml for Ery, 16 \u03bcl for Oxy, and 32 \u03bcl for Sp, of the 33 P. haemolytica isolates, 32 were resistant to Oxy, 27 to Sp, and 14 to Ery. Based on the fractional inhibitory concentration index, Ery and Oxy in combination were synergistic or additive against 32 of 33 isolates. The combination of Ery and Sp was synergistic or additive against 27 of 33 isolates. No instances of antagonism were seen. When the effects were considered within the context of therapeutically achievable serum\/tissue concentrations, the effects of Ery and Oxy in combination were only marginal. Thus, against P. haemolytica isolates, Ery and Sp appeared to represent an effective antimicrobial combination, whereas Ery and Oxy were only of marginal efficacy as a combination.<\/jats:p>","DOI":"10.1177\/104063878900100404","type":"journal-article","created":{"date-parts":[[2011,5,12]],"date-time":"2011-05-12T16:10:00Z","timestamp":1305216600000},"page":"299-304","source":"Crossref","is-referenced-by-count":9,"title":["In Vitro Assessment of the Efficacy of Erythromycin in Combination with Oxytetracycline or Spectinomycin against\n                    <i>Pasteurella Haemolytica<\/i>"],"prefix":"10.1177","volume":"1","author":[{"given":"George E.","family":"Burrows","sequence":"first","affiliation":[{"name":"Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078-0353"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Patty","family":"Ewing","sequence":"additional","affiliation":[{"name":"Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078-0353"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[1989,10,1]]},"reference":[{"key":"bibr1-104063878900100404","doi-asserted-by":"publisher","DOI":"10.1093\/jac\/9.suppl_A.35"},{"key":"bibr2-104063878900100404","first-page":"299","volume-title":"Antibiotics: Assessment of antimicrobial activity and resistance","author":"Beale AS","year":"1983"},{"key":"bibr3-104063878900100404","doi-asserted-by":"publisher","DOI":"10.1097\/00000441-196312000-00013"},{"key":"bibr4-104063878900100404","doi-asserted-by":"crossref","first-page":"798","DOI":"10.2460\/ajvr.1985.46.04.798","volume":"46","author":"Burrows GE","year":"1985","journal-title":"Am J Vet Res"},{"key":"bibr5-104063878900100404","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2885.1986.tb00032.x"},{"key":"bibr6-104063878900100404","doi-asserted-by":"publisher","DOI":"10.1016\/S0021-9258(18)65573-5"},{"key":"bibr7-104063878900100404","first-page":"77","volume":"26","author":"Fales WH","year":"1983","journal-title":"Proc Annu Meet Am Assoc Vet Lab Diagn"},{"key":"bibr8-104063878900100404","doi-asserted-by":"publisher","DOI":"10.1177\/104063878900100106"},{"key":"bibr9-104063878900100404","first-page":"43","volume":"24","author":"Fales WH","year":"1981","journal-title":"Proc Annu Meet Am Assoc Vet Lab Diagn"},{"key":"bibr10-104063878900100404","unstructured":"Gale EF, Cunliffe E, Reynolds PE, 1981. 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