Antimicrobial resistance among important bovine pathogens isolated at the KSU Veterinary Diagnostic Laboratory over two and a half years

Kansas Agricultural Experiment Station Research Reports, Dec 1993

A retrospective study was conducted to determine the prevalence of antimicrobial resistance among six important bacterial pathogens of bovine origin. The study extended from June 1990 through December 1992 and included a review of the microbiology records of bovine submissions to the KSU Veterinary Diagnostic Laboratory. Antimicrobial susceptibility results for Pasteurella haemolytica, Pasteurella multocida, Actinomyces pyogenes, Hemophilus somnus, Escherichia coli, and Salmonella spp. are summarized. Pathogens were recovered primarily from cases of pneumonia and/or diarrhea. Each isolate was tested for susceptibility to 14 different antimicrobial agents. A high prevalence of resistance (>70%) was noticed for respiratory pathogens to sulfachloropyridazine. In addition, Pasteurella spp. were very resistant (>71%) to sulfadimethoxine. Most of the H. somnus isolates showed little resistance (<35%) to 12 of the 14 drugs tested. A. pyogenes isolates were generally susceptible to most antimicrobials except sulfa drugs. As expected, a high prevalence of resistance (>70%) was noticed for enteric pathogens (Salmonella and E. coli) to most of the antimicrobials tested.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

http://newprairiepress.org/cgi/viewcontent.cgi?article=2144&context=kaesrr

Antimicrobial resistance among important bovine pathogens isolated at the KSU Veterinary Diagnostic Laboratory over two and a half years

Antimicrobial resistance among important bovine pathogens isolated at the K SU Veterinar y Diagnostic Laborator y over two and a half years D.P. Rogers 0 1 2 M.W. Vorhies 0 1 2 M. M. Chengappa 0 1 2 0 This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 1993 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. Brand names appearing in this publication are for product identification purposes only. K-State Research and Extension is an equal opportunity provider and employer , USA 1 Tribrissen , 1/19,2/38 2 Penicillin G , 0.12,2 Follow this and additional works at: http://newprairiepress.org/kaesrr Part of the Other Animal Sciences Commons Recommended Citation Rogers, D.P.; Vorhies, M.W.; and Chengappa, M. M. (1993) "Antimicrobial resistance among important bovine pathogens isolated at the KSU Veterinary Diagnostic Laboratory over two and a half years," Kansas Agricultural Experiment Station Research Reports: Vol. 0: Iss. 1. https://doi.org/10.4148/2378-5977.2144 - Antimicrobial resistance among important bovine pathogens isolated at the KSU Veterinary Diagnostic Laboratory over two and a half years Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 License. This Research Report article is available in Kansas Agricultural Experiment Station Research Reports: http://newprairiepress.org/ kaesrr/vol0/iss1/741 ANTIMICROBIAL RESISTANCE AMONG IMPORTANT BOVINE PATHOGENS ISOLATED AT THE KSU VETERINARY DIAGNOSTIC LABORATORY OVER TWO AND A HALF YEARS Summary A retrospective study was conducted to determine the prevalence of antimicrobial resistance among six important bacterial pathogens of bovine origin. The study extended from June 1990 through December 1992 and included a review of the microbiology records of bovine submissions to the KSU Veterinary Diagnostic Laboratory. Antimicrobial susceptibility results for Pasteurella haemolytica, Pasteurella multocida, Actinomyces pyogenes, Hemophilus somnus, Escherichia coli, and Salmonella spp. are summarized. Pathogens were recovered primarily from cases of pneumonia and/or diarrhea. Each isolate was tested for susceptibility to 14 different antimicrobial agents. A high prevalence of resistance (>70%) was noticed for respiratory pathogens to sulfachloropyridazine. In addition, Pasteurella spp. were very resistant (>71%) to sulfadimethoxine. Most of the H. somnus isolates showed little resistance (<35%) to 12 of the 14 drugs tested. A. pyogenes isolates were generally susceptible to most antimicrobials except sulfa drugs. As expected, a high prevalence of resistance (>70%) was noticed for enteric pathogens (Salmonella and E. coli) to most of the antimicrobials tested. Introduction Pneumonia and diarrhea in cattle of all ages can be initiated by a variety of microbial agents, but only the bacteria involved in these conditions are the major targets of antimicrobial therapy. Antimicrobial susceptibility profiles are important in determining appropriate therapy against those bacterial pathogens. A major problem facing veterinarians is deciding quickly what drug and dosage will be effective in treating cattle affected with these conditions. This is increasingly difficult, because drug resistance appears to be increasing steadily. Because many bacteria develop resistance to antimicrobial agents, isolation of an infectious agent from an animal is often not sufficient to determine proper treatment. Susceptibility profiles of bacteria are constantly changing; thus, a veterinarian must know the antimicrobial sensitivity profile of bacteria in question before treatment. This retrospective study determined the prevalence of antimicrobial resistance among important cattle pathogens recovered from cases of pneumonia and diarrhea. Experimental Procedures (Key Words: Resistance, Disease, Bacteria, Treatment, Cattle.) Bacterial pathogens were recovered from cattle that had died from pneumonia and/or 1KSU College of Veterinary Medicine, Department of Pathology and Microbiology, and Veterinary Diagnostic Investigation, respectively. diarrhea and had been evaluated at the KSU Veterinary Diagnostic Laboratory between June 1990 and December 1992. The pathogens were isolated and identified biochemically and serologically using standard procedures. Susceptibility testing of bacteria was performed with the automated Sensititre System (Sensititre Microbiology System, Westlake, OH). The antimicrobial agents and their concentrations are presented in Table 1. Results and Discussion Enteric pathogens such as Salmonella and E. coli were more resistant to antimicrobials than pneumonic pathogens such as Pasteurella, Haemophilus, and Actinobacillus (Table 1). This agrees with recent findings of other researchers. Ceftiofur (Naxcel®) still appeared to be very effective against all respiratory and enteric pathogens tested. However, these in vitro observations should be used only as a guide to antimicrobial selection. Resistance to these drugs may develop through increased use, so continued surveillance is warranted. In the present study, the animals or tissues evaluated tended to be from herds where treatment response was nil and death losses were heavy. Thus, these data represent the high prevalence of drug resistance among bacteria associated with cases of pneumonia and diarrhea. Specimens collected prior to death, during early course of disease, or prior to treatment also might show antimicrobial resistance. Percentage of Resistant Bacteria Recovered from Bovine Pneumonic and Diarrheic Cases Antimicrobial P. haemolytica P. multocida H. somnus A. pyogenes Salmonella E. coli Total % Res. Total % Res. Total % Res. Total % Res. Total % Res. Total % Res. Tylosin 297 88 215 83 49 21 91 22 167 99 (5,10) aNumber in paretheses indicates concentration of drugs in µg/ml. bCeftiofur (Naxcel®) concentration was increased from .2 and .4 to 1 and 2 µg/ml on October 1, 1991. 95 55 95 95 95 95 95 95 91 55 55 95 55 30 11 14 16 24 14 49 18 34 80 69 26 44 174 66 174 174 174 174 174 174 171 66 66 174 66 66 28 6 8 99 29 66 99 97 90 99 78 15 828 343 828 828 828 828 828 828 827 343 343 828 343 825 60 7 26 5 99 20 58 99 58 87 94 79 34 99 agentsa Ampicillin (2,4,8) Ceftiofur (1,2)b Cephalothin (8,16) Enrofloxacin (1,4) Erythromycin (0.5,4) Gentamicin (4,8) Neomycin (8) Penicillin G (0.12,2) Spectinomycin (8,16) Sulphadimethoxine (20,40) Tetracycline (4,8) 297 106 297 297 297 297 297 297 297 106 106 297 106 49 2 9 8 6 27 34 51 82 68 72 52 11 216 126 216 216 216 216 216 216 215 126 126 216 126 32 15 10 8 30 10 49 35 79 79 71 36 13 49 21 49 49 49 49 49 49 49 21 21 49 21


This is a preview of a remote PDF: http://newprairiepress.org/cgi/viewcontent.cgi?article=2144&context=kaesrr

D.P. Rogers, M.W. Vorhies, M. M. Chengappa. Antimicrobial resistance among important bovine pathogens isolated at the KSU Veterinary Diagnostic Laboratory over two and a half years, Kansas Agricultural Experiment Station Research Reports, 1993,