Isolation and characterization of sheep salmonellae in and around Bangladesh Agricultural University campus

Abstract

The study was carried out for isolation of Salmonella spp. and their characterization from sheep during the period from November 2006 to May 2007. For this study a total number of 63 rectal swab samples of sheep were collected. Out of 63 samples, 9 samples were identified as positive for Salmonella and each positive sample was treated as one isolate. All the Salmonella isolates revealed the same morphological, cultural and biochemical characteristics. In the stab culture on TSI agar slant, all of the isolated Salmonella isolates produced acid (yellow) and gas in the butt, the production of hydrogen sulfide gas in both butt and slant, and the alkaline (red) reaction in the slant. For the slide agglutination test, Salmonella agglutinating antiserum (poly ‘O' and poly ‘H') was used which agglutinated all the isolates and thereby identified the organism as Salmonella. The pathogenicity of the isolates was studied in mice and it revealed that the isolates were pathogenic. After isolation of Salmonella, eight commonly used antibiotics were used for the antibiogram study of isolated Salmonella. Among the isolates, 77.78% were highly sensitive and 22.22% were moderately sensitive to ciprofloxacin and spiramycin, 66.67% were highly sensitive and 33.33% were moderately sensitive to gentamicin. 55.56% were moderately sensitive and 44.44% were less sensitive to oxytetracycline and streptomycin, 33.33% were moderately sensitive and 66.67% were less sensitive to amoxycillin, 11.11% were moderately sensitive, 33.33% were less sensitive and 66.67% were resistant to sulphamethoxazole, 11.11% were less sensitive and 88.89% were resistant to penicillin-G.  From the results it may be concluded that the prevalence of Salmonella organisms in sheep of this country is remarkable and isolated Salmonella spp. are pathogenic for laboratory animals and highly sensitive to ciprofloxacin, spiramycin and gentamicin. From the results it also may be concluded that slide agglutination test can be used for the rapid detection of Salmonella organism. Key words: isolation, characterization, pathogenicity, antibiogram study DOI = 10.3329/bjvm.v6i1.1346 Bangl. J. Vet. Med. (2008). 6 (1): 75-78