7 research outputs found
Antimicrobial resistance among important bovine pathogens isolated at the KSU Veterinary Diagnostic Laboratory over two and a half years
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
Causes of diarrhea, pneumonia, and abortion in 1991 cattle submissions to the KSU Veterinary Diagnostic Laboratory
Causes of diarrhea, pneumonia, and abortion
in Kansas cattle submissions to the Kansas
State University Veterinary Diagnostic Laboratory
during 1991 were summarized. Antimicrobial
susceptibility results for Pasteurella
haemolytica, Pasteurella multocida, Hemophilus
somnus, and Salmonella spp., the common
causes of pneumonia and/or diarrhea in cattle
with increasing antibiotic resistance patterns,
were also summarized. The most commonly
diagnosed causes of diarrhea in young calves
(under 1 month of age) were coronavirus,
Escherichia coli, and Salmonella. The three
most common causes of diarrhea in 1 to 18
month-old cattle were BVD virus, coccidia,
and Salmonella. Most respiratory submissions
were 7- to 18-month-old cattle. P.
haemolytica and P. multocida were the most
commonly identified pathogens from these
cattle. In 20% of the cases, more than one
pathogen was identified. The most commonly
diagnosed cause of abortion was bacterial
infection (20%), but a cause was not identified
in nearly 70% of abortion submissions
Causes of diarrhea, pneumonia, and septicemia in swine for 1991 submissions to the KSU Veterinary Diagnostic Laboratory
Causes of pre- and postweaning diarrhea,
pneumonia, and bacterial septicemia in pigs
were summarized for fiscal year 1991 (July,
1990 to June, 1991) for submissions to the
Kansas State University Veterinary Diagnostic
Laboratory. Escherichia coli was the most
common cause of both pre- and postweaning
diarrhea in pigs (33.5% and 25.0%, respectively, of submissions for diarrhea). Other commonly diagnosed causes included transmissible gastroenteritis (24.4%) and coccidiosis (16.5%) for preweaning diarrhea, and proliferative enteritis (19.2 %) and salmonellosis (13.2 %) for postweaning diarrhea. The most commonly diagnosed causes of pneumonia in nursing, growing, and finishing pigs were Pasteurella multocida, Mycoplasma, and Actinobacillus (Haemophilus) pleuropneumoniae. Streptococcus and Salmonella were common causes of bacterial septicemia in Kansas pigs
Growth and microbiology of nonmedicated, segregated, early-weaned pigs
Seventy pigs, 7 to 10 d of age, were randomly selected by litter of origin from a
commercial farm in Northeast Kansas to
compare the growth and microbiology of
nonmedicated, segregated, early-weaned pigs to controls raised at the farm of origin. After weaning, both groups were fed a similar nutritional programs consisting of
dry diets. No antimicrobial drugs were
administered to the pigs except for a feed
grade antimicrobial (carbadox) from weaning
to 50 lb. Pigs were monitored for 12 weeks. Individual pigs weights, nasal swabs, and serum samples were collected on d 0 and then every 14 d thereafter for a total of 7 collections. Four pigs were necropsied at the initiation of the study (d 0). In addition, four pigs were randomly selected at each collection period from each group for necropsy and collection of tissues
for bacterial culture. The segregated earlyweaned pigs were able to reach an accelerated phase of growth before the controls. On d 14, 28, 42, 56, and 70 of the experiment, segregated early-weaned pigs were
21, 82, 90, 54, and 52% heavier than control
pigs, respectively. A low percentage of pigs were infected with Pasteurella multocida at 7 to 10 d of age, which corresponds to d 0 of the experiment. The principal time of transmission of P. multocida infection was in the immediate postweaning period. The rate of isolation of P. multocida then declined from d 14 to d 84 of the experiment in both groups of nonmedicated pigs. This response must be kept in mind when evaluating the efficacy of antibiotic protocols. Appropriate nonmedicated controls must also be evaluated. The maximum difference in rate of isolation of P. multocida from nasal swabs and tissues between the early and control groups occurred on d 28 and d 42 of the experiment.
This corresponds to the two collection days when segregated early-weaned pigs were 82% and 90% heavier than control pigs raised on-site. The only Pasteurella multocida isolates capable of producing toxin were detected on d 14 in the control group. Pasteurella multocida toxin has also been shown to have deleterious effects on systemic organs and immune response. The rates of Bordetella bronchiseptica isolation were similar between control and segregated early-weaned groups. However, B. bronchiseptica isolates were recovered from any tissues of any pigs necropsied. Antibiotic regimens targeted at this organism would appear unwarranted in a commercial production setting. Haemophilus parasuis and Streptococcus suis were present in both groups of pigs at 7 to 10 d of age. However, as indicated by the excellent growth performance achieved in the presence of H. parasuis colonization of the nasal cavity, elimination of this organism probably is not necessary to achieve excellent growth levels. More studies need to be undertaken to understand the mode of transmission and epidemiology of Streptococcus suis infection. Mycoplasma hyopneumoniae apparently was eliminated without medication by moving pigs to an isolated site. Mycoplasma hyopneumoniae could be detected only in the control group. Data from this experiment also suggest that weaning pigs at 14 to 17 d could prevent vertical transmission of Actinobacillus pleuropneumonia. The growth and microbiology of nonmedicated, segregated, early-weaned pigs must be considered when developing cost-effective and efficacious medication protocols for application of segregated early weaning in the commercial swine industry