ABSTRACT
Infectious bursal disease [IBD] is a highly contagious disease of chickens caused by the infectious bursal disease virus [IBDV]. This study was conducted to characterize three IBDV strains from Iran. A reverse transcriptase-polymerase chain reaction [RT-PCR] procedure was used to amplify a 715-bp fragment of the VP1 gene from IBDV strains. Amplified VP1 fragments of the three Iranian IBDV strains were sequenced and compared with published sequences of IBDV strains from around the world, and their phylogenetic relationships were analyzed. Alignment of IBDV strains revealed 23 nucleotide differences between vvIBDV [except for IL and PT] and other non-vvIBDV strains. Two nucleotide positions, 863G and 1023A, were specific as JRMP07IR and JRMP14IR strains. All vvIBDVs differed [except for IL and PT strains] from non-vvIBDVs at aa [amino acids] positions 242E and 287A. In the three Iranian IBDV strains, aa positions 251R in both JRMP07IR and JRMP14IR, and 360L in JRMP14IR differed from those of other vvIBDVs. In phylogenetic analyses, all three Iranian strains clustered together with vvIBDVs. One Iranian strain, JRMP30IR, was more closely related to two European strains [HOL and UK661] and two south-east Asian strains [OKYM and ZJ2000]. However, the other two Iranian strains, JRMP07IR and JRMP14IR, were closer to two Turkish strains [OA/G1 and OE/G2] and a Malaysian strain [UPM94]. Further comprehensive investigations will provide researchers a better knowledge on the distribution, variability, and phylogenetic relationships of different IBDVs isolated in Iranandother parts of the world. Key words: Infectious bursal disease virus, Very virulent strains, VP1, Chicken, Iran
ABSTRACT
Different susceptibility rates of pathogenic bacteria to antimicrobial agents are considered major factors in the choice of drugs and the success of treatments. Concerns have been raised regarding the emergence of antimicrobial resistance among pathogenic bacteria that may result in unpredictable antimicrobial susceptibilities and therapy failure. The purpose of this investigation was to determine the antimicrobial susceptibility of 1,000 bacterial isolates to five antibacterial agents commonly used in the Iranian poultry industry. From July 2008 to June 2009, the antimicrobial susceptibility of 1,000 bacterial isolates to five antibacterial agents was tested. These agents that are commonly used in the Iranian poultry industry include colistin, doxycycline, enrofloxacin, florfenicol, and sulfamethoxazole + trimethoprime. The data were provided by 19 laboratories in eight Iranian provinces. The bacterial species belonged mainly to Escherichia coli and Salmonella spp. Of all tested samples, 55.5% were resistant to colistin, 61.5% to doxycycline, 41.5% to enrofloxacin, 34.5% to florfenicol, and 65.5% to sulfamethoxazole+trimethoprime. The findings of this survey represent the high frequency of resistance to antimicrobial agents commonly used in the Iranian poultry industry. They also highlight the need for the implementation of a national monitoring program for antimicrobial resistance and for a rational use of antimicrobial drugs