Isolation and characterization of Streptococcus bovis from rumen content of Awassa sheep in Iraq

الملخص EN

This is the first study in Iraq aimed to isolate and characterize Streptococcus bovis from rumen of Awassi sheep .Ten sheep with different ages fed on grain base diet for three days were used to collect 20 ruminal fluid samples twice at fourth and fifth days by rumenocentesis method , samples cultured on selective media (Modified membrane-bovis agar(M-BA) ,broth of basal medium and modified blood brain heart infusion) ,the isolates were identified according to their morphological, physiological ,biochemical tests and serological by Lancefield group.Cultural characteristic on the selective medium M-BA showed two types of streptococci :first type (23) comprised the majority of isolates ,this type characterized by high acid producing streptococci formed mucoid ,creamy ,orange –centered colonies and second type (4) characterize by low acid producing formed small white colonies .Morphologically the isolates were identified as gram positive ,the cells were oval or spherical , singles, pairs & short chains of 4 to 8 cells.

The organisms were found to full under the Lancefield group D.All isolated bacteria grew on broth of basal medium post incubation at 45C˚ ,but not grew at 10C˚ and 50C˚.

Adding of 2% NaCl permit the growth, while in 6.5% NaCl didn’t grow.

And did not grew on adding 0.04 % Potassium tellurite .All isolates produced lactic acid but ammonia production from arginine was negative, no hemolysis on blood agar .

All isolates ferment starch, lactose, fructose, glucose, raffinose and cellobiose.The results of culturing and Physiological and biochemical tests showed that 27 isolates has the characterictices of Streptococcus bovis in 3 types (S1,S2 &S3) ,first type of colony divided into two strain (S115)(S28)according to difference In arabinose.

And (S3) called on the second type white pigmented isolates which did not ferment inulin