عنوان

Staphylococci of bovine mammary gland:

Number

TLpq304003688

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

Staphylococci of bovine mammary gland:

General Material Designation

[Thesis]

First Statement of Responsibility

G. Muhammad

Title Proper by Another Author

Conventional and molecular dynamics of infections, plasmid stability, reproducibility, and interspecific conjugal transfer of antibiotic resistance

Subsequent Statement of Responsibility

K. H. Hoblet

Name of Publisher, Distributor, etc.

The Ohio State University

Date of Publication, Distribution, etc.

1992

Specific Material Designation and Extent of Item

206

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

The Ohio State University

Text preceding or following the note

1992

Text of Note

Quarter foremilk and streak canal swab samples were taken from 45 cows and 38 heifers within first three days, days 13 to 15 and days 20 to 22 postpartum. In addition, in cows similar samples were taken for 3 consecutive days at the cessation of lactation. At calving, 34.4 and 44.7% of cow and heifer quarters, respectively harbored staphylococci. Corresponding figures 3 weeks later were 15 and 19.1%. Thus, there was significant reduction in the prevalence of quarters harboring staphylococci in both cows and heifers (P < 0.05). At calving 44.4 and 59.9% of cow and heifer streak canal, respectively harbored staphylococci. There was nonsignificant (P > 0.05) reduction of 14.9% in the prevalance of streak canals harboring staphylococci in cows after calving. In heifers, a significant reduction (P < 0.05) of 27.5% in the prevalence of streak canals harboring staphylococci was observed. The sampling reliability of streak canal staphylococcal isolations was half that of the quarter isolation. At calving, 46 and 47.4% of all milk isolates in cows and heifers, respectively had STAPH-Trac profiles identical with those of the streak canal. In 15 cows and 15 heifers, persistence of infection, inter- and intraquarter identities of isolates observed on the basis of species determination were evaluated on the basis of biotyping and plasmid profiles-antibiogram patterns of isolates. Biotyping alone was useful in revealing interstrain differences in S. xylosus and S. epidermidis. Plasmid profile-antibiogram was able to distinguish among strains having the same biochemical profiles. Different quarters of an animal were infected with different strains of a species. Seven of 8 test isolates harbored stable plasmids under conditions of repeated subculturing. The reproducibility of plasmid profiles using mutanolysin was comparable with that using lysostaphin. Deviations of usd\leusd5 mm in the zone sizes resulted in the shift of susceptibility categories. To determine the transferability of antibiotic resistance from CNS to S. aureus and among different coagulase-negative staphylococcal species, 126 matings were performed among 37 isolates. No transfer of penicillin, tetracycline and erythromycin resistance was detected. Two strains transferred streptomycin resistance to two S. aureus strains and one S. chromogenes. Conjugation was determined to be the process of resistance transfer.

Biological sciences

Microbiology

Molecular biology

Molecular biology

Veterinary services

Veterinary services

G. Muhammad

K. H. Hoblet

Electronic name

p

[Thesis]

276903

a

Y