ISOLATION, IDENTIFICATION AND ANTIBIOGRAM STUDY OF Escherichia coli AND Shigella spp. FROM FECAL SAMPLE OF TIGER AND LION AT DHAKA ZOO

Abstract

Escherichia coli and Shigella spp. isolated from fecal samples of tiger and lion collected from Dhaka Zoo and samples were identified in the Bacteriology Laboratory of Bangladesh Livestock Research Institute,. Savar, Dhaka during the period from July to December 2014. A total of 40 samples, 18 from Tiger and 22 from Lion fecal samples were collected aseptically and subjected to primary isolation by propagating in nutrient broth followed by culture on different agar media and both. Gram’s staining and hanging drop techniques were also performed. Biochemical properties of the isolates were studied. Author found that 65% samples were E. coli positive. On the other hand 35% samples were revealed as Shigella containing samples. All the E. coli isolates were found to produce bright pink colonies on MacConkey agar, yellowish green colonies surrounded by an intense yellow green zone on Brilliant Green (BG) agar and characteristic metallic sheen colonies on the Eosine Methyline Blue (EMB) agar. In Gram’s staining technique, all the isolates were pink coloured, indicating Gram negative small bacilli while in the hanging drop technique the organisms were motile. All the E. coli isolates fermented dextrose, maltose, lactose, sucrose and mannitol with the production of both acid and gas. The results of catalase, MR and indole tests with E. coli isolates were positive but V-P test was negative. All the isolated Shigella spp. produced colorless colonies on MacConkey agar, SS agar and EMB agar. During biochemical test all the Shigella isolates ferment dextrose and lactose quickly and sucrose slowly by produced only acid but gas. In Gram’s staining showed pink color medium size, rod shaped organism and non motile in hanging drop slide. In antibiotic sensitivity test, most of the E. coli isolates were sensitive to Ciprofloxacin (CIP), Ceftriaxone (CRO), Azithromycin (AZM) and Cefotaxime (CTX) and resistant to Oxytetracyclin (OT), Erythromycin (E), Amoxicillin/Clavulanic acid (AMC) and Cephradin (CE). Isolated Shigella spp. were revealed sensitive to Ciprofloxacin (CIP), Ceftriaxone (CRO), intermediately sensitive to Amoxicillin/Clavulanic acid (AMC) and resistant to Oxytetracyclin (OT), Erythromycin (E), Azithromycin (AZM) and Cephradin (CE).