Isolation and antibiotic resistance profile of Streptococcus spp from commercial poultry carcasses in Ardabil province, northwest of Iran

Abstract

Farmers use antibiotics for prophylaxis and therapy to maintain the production. However, widespread use of antibiotic is increased antibiotic resistance. The present study was carried out to isolate and identify Streptococcus spp involved in commercial poultry carcasses and also to examine isolated bacteria for antibiotic resistance profile. Samples were taken from heart blood and liver’s visceral surface of 125 carcasses obtained from 30 commercial flocks (including 27 broiler flocks, 1 laying flocks and 2 breeder flocks) located in different parts of Ardabil province, northwest of Iran. Streptococcus spp isolates were identified based on microbiological standard methods. The antibiotic susceptibility test was performed using the Kirby-Bauer disk diffusion method. Out of 125 collected carcasses, bacteria isolates 98 were diagnosed. Among them, 6 (6.13 %) of isolates were confirmed to be Streptococcus spp. The strains exhibited high percentages of resistance to Ampicillin (100 %) and Doxycycline (100 %) and low percentages of resistance to Clindamycin (16.7%) and Cefatoxaime (0.0 %). Neomycin, Enrofloxacin, Erythromycin, Gentamycin, Ciprofloxacin  and Chloramphenicol were resistant with 83.4 %, 83.4 %,  66.7 %,  50.0 %, 33.4 % and 33.4 %. The present study showed that poultry products, especially infectious lesions of liver and heart of poultry carcasses can be an important source of contamination and dissemination of drug-resistane Streptococcus spp. Therefore, performing antimicrobial sensitivity test is necessary prior to prescribing any antibiotic in commercial poultry.