The prevalence and virulence of Salmonella isolates from pigs in Hiep Hoa district, Bac Giang province, Viet Nam

Abstract

The study was conducted to determine the infection rate and virulent factors of Salmonella bacteria isolating from 256 sows in 20 breeding farms in Hiep Hoa district, Bac Giang province, Viet Nam. The studied result showed that the serotype of 2/166 positive samples with Salmonella weltevreden; 3/166 positive samples with Salmonella dublin; 5/166 positive samples with Salmonella anatum and Salmonella senftenberg; 6/166 positive samples with Salmonella heidelberg; 9/166 positive samples with Salmonella enteritidis; 30/166 positive samples with Salmonella typhimurium, 41/166 positive samples with Salmonella choleraesuis, and 10/166 positive samples with Salmonella were unknown. The isolated Salmonella strains carried the virulent genes, including the Salmonella typhimurium, Salmonella enteritidis and Salmonella choleraesuis strains bearing Stn gene (causing enteritidis) accounted for 73.3%, 88.8%, and 92.6%, respectively. The Salmonella typhimurium, Salmonella enteritidis, Salmonella choleraesuis strains bearing fimA gene accounted for 66.6%, 88.8%, and 92.6%, respectively. The Salmonella typhimurium, Salmonella choleraesuis and Salmonella enteritidis strains bearing InvA gene accounted for 26.6%, 39.0%, and 66.6%, respectively. The rate of Salmonella choleraesuis strain resisting nalidixic acid; ciprofloxacin, rifampicin, spectinomycin; ceftazidime, oxytetracycline; nitrofurantoin; trimethoprim-sulfamethoxazole; kanamycin was 2.4%, 7.3%, 9.7%, 12.1%, respectively. The rate of Salmonella enteritidis strain resisting ciprofloxacin, rifampicin, ceftazidime, spectinomycin, nitrofurantoin; trimethoprimsulfamethoxazole, kanamycin was 11.1%, 22.2%, respectively. The rate of Salmonella typhimurium strain resisting nitrofurantoin, nalidixic acid and ceftazidime; ciprofloxacin, spectinomycin and rifampicin; trimethoprim-sulfamethoxazole; kanamycin was 3.3%, 6.6%, 16.6%, 20.0%, respectively. The isolated Salmonella strains were strongly susceptible with nalidixic acid, oxytetracycline, ceftazidime, rifampicin, ciprofloxacin and nitrofurantoin. They also resisted to the above mentioned antibiotics at various levels. Of which, resistance to trimethoprim-sulfamethoxazole, spectinomycin, and kanamycin accounted for the highest rate.