Prevalencel of Imstitic Staphylococci Str eptococci and coliflorm (Escherichia Coli) in Threee Dairy Farhs in and Around Addis Ababa
No Thumbnail Available
Date
1988-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Prevalence of mastitic staphylococci, streptococci & coliform species
in foremilk samples of apparently healthy lactating cows was studied in
3 dairy farms. One hundred & twenty apparently healthy lactating cows
were randomly selected on the basis of lactation numbers. These were 40
from Debre Zeit, 40 from Repi & 40 from Kumbi dairy farms. Pooled foremilk
samples \~ere co11ected from the teats of each lactating cO\~ & totally
120 foremilk samples were collected & analysed from the 3 farms.
The total mesophilic aerobic bacterial, streptococcal & staphylococcal
counts & the bacterial counts of Staphylococcus & Streptococcus species
were estimated using different kinds of media. The susceptibilities of
55 isolates of mastitic staphylococcal & streptococcal strains to 11
antibiotics was determined using the standard agar disc diffusion
technique.
The total mesophilic aerobic bacterial counts was highly variable &
ranged from hundreds to mi11ions in a11 of the dairy farms. The high total
mesophilic aerobic bacterial counts greater than or equal to 1 x 105
colony forming units I mi11iliter were mainly associated with high numbers
of streptococcal counts. Staphylococci were regularly isolated in all
foremilk samples, however, their contribution to increases in the total
mesophilic aerobic bacterial count was not as significant as that of
rd '
streptococci. At the 3 & subsequent lactations, the number of co\~s
that had total mesophilic aerobic bacterial counts'greater than or equal
to 2xl04 colony forming units/milliliter increased at Kumbi & Repi
farms. At the Debre Zeit farm, with increases in lactation numbers the
number of cows that had greater than or equal to lxlO 5 colony forming
units/milliliter was high.Five hundred & thirty five isolates were biochemically tested from
the 120 samples. Of these 312 belonged to Staphylococcus, 215
belonged to Streptococcus, 6 belonged to Micrococcus & 2 belonged to
coliform. Five species & 2 subspecies of staphylococci, 7 species of
streptococci & 1 coliform species were identified. Among mastitic
staphylococci, Staphylococcus epidermidis was the most prevalent and was
isolated from 80.8% of the foremilk samples, followed by Staphylococcus
aureu~ (20%), Staphylococcus hyi~ subsp. chromogenes (12.5%),
Staphylococcus hyicus subsp. hyicus (5.8%). Similarly, other
Staphylococcus species were also isolated in different proportions:
Staphylococcus simulans (6.7%), Staphylococcus xylosus (4.2%),
Staphllococcus intermedius (0.83%) & Staphylococcus hominis/Staphylococcus
w~rneri / Staphylococcus haemolyticus group (6.7%).
Of the mastitic streptococcal strains, Streptococcus bovis was the
most prevalent &was isolated from 40.8% of the lactating cows sampled,
followed·by Streptococcus uberis (15.8%), Streptococcus dysagalactiae
(14.2%), Streptococcus agalactiae (9.2%), Streptococcus faecalis (5%),
Streptococcus sp. G (5.8%) & Streptococcus infrequens (0.8%). Other
streptococcal strains were also isolated. Streptococcus lactis lias
detected in 0.8% of the samples.
Generally the frequency of isolation for Streptococcus uberis,
Streptococcus dysagalactiae, Streptococcus agalactiae & Staphylococcus
aureus was high during the latter lactation numbers (3, 4 & 5).
Escherichia coli was not common in the herds & was detected in
1.7% of the foremilk samples from one herd only.
Among 30 isolates of staphylococcal strains tested, 26.7% lIere
resistant to penicillin & tetracycline. All the staphylococcal strainsliere sensitive to erythromycin, oxacillin, cephalothin, chloramphenicol,
kanamycin, gentamycin, streptomycin, clindamycin & vancomycin.
Of 25 isolates of streptococcal strains, resistance to oxacillin,
tetracycline, kanamycin, gentamycin, streptomycin was sholin by 8, 23, 8
16 & 40% of the iso1ate~. respectively. All the streptococcal strains were
sensitive to penicillin, erythromycin, cephalothin, c1indamycin,
vancomycin & chloramphenicol.
Description
Keywords
Biology