Objective—To determine whether Mycoplasma
strains typically associated with mastitis in dairy cattle
can be isolated from body sites other than the
Design—Prospective clinical trial.
Animals—7 Holstein cows in various stages of lactation
with intramammary Mycoplasma infection.
Procedure—Milk samples, antemortem swab specimens
from various body sites, and postmortem swab
and tissue specimens were submitted for Mycoplasma
culture. Pulsed-field gel electrophoresis (PFGE) was
performed on chromosomal digests of all Mycoplasma
isolates. Isolates with the same number and size of
chromosomal digest bands were considered to be of
the same type.
Results—For each cow, all isolates obtained from
milk, mammary gland parenchyma, and supramammary
lymph nodes had the same PFGE pattern. All
cows had at least 1 isolate from nonmammary system
tissues that had the same PFGE pattern as isolates
from the mammary system. Overall, 44 of the
70 (63%) Mycoplasma isolates obtained from body
sites other than mammary system sites had the
same PFGE pattern as did mammary system isolates.
Conclusions and Clinical Relevance—Results confirmed
our hypothesis that Mycoplasma strains isolated
from the milk of dairy cattle with Mycoplasma
mastitis frequently have PFGE patterns identical to
those for strains isolated from other body sites, suggesting
that there is at least a potential for internal
transmission of Mycoplasma organisms. (J Am Vet
Med Assoc 2005;227:455–459)