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 strai...

In this study, twenty-five strains of Mycobacterium tuberculosis resistant to isoniazid (INH) were isolated from patients with tuberculosis (TB). Nine strains (36%) were found to be virulent in guinea-pigs [root index virulence (RIV» 1 ]. The remaining sixteen strains (64%) were non-virulent (RIV <1). Of the nine strains resistant to INH as well as virulent to guinea-pigs, eight of them wer...

in this study, twenty-five strains of mycobacterium tuberculosis resistant to isoniazid (inh) were isolated from patients with tuberculosis (tb). nine strains (36%) were found to be virulent in guinea-pigs [root index virulence (riv» 1 ]. the remaining sixteen strains (64%) were non-virulent (riv <1). of the nine strains resistant to inh as well as virulent to guinea-pigs, eight of them were fo...

Streptococcus suis is an important zoonotic pathogen. However, identification of virulent S. suis strains is complicated because of the high diversity of the species. Here we evaluated the genetic difference among S. suis strains using comparative genomic hybridization (CGH) and virulence variation in vivo and in vitro. We showed that different clades differed in their ability to activate TLR2/...

Virulent strains of Salmonella opsonized with normal mouse plasma are never phagocytosed as well as avirulent strains. The virulent strains of Salmonella phagocytosed after opsonization with normal mouse plasma are able to multiply within normal mouse peritoneal macrophages, whereas under similar experimental conditions the avirulent strains are killed. When virulent strains of Salmonella are o...

Xanthomonas arboricola is a plant-associated bacterial species that causes diseases on several plant hosts. One of the most virulent pathovars within this species is X. arboricola pv. pruni (Xap), the causal agent of bacterial spot disease of stone fruit trees and almond. Recently, a non-virulent Xap-look-a-like strain isolated from Prunus was characterized and its genome compared to pathogenic...

Ethanol extract of propolis (EEP) has antibacterial, antiviral, antiprotozoal and antifungal properties, in addition to many biological effects. Our laboratory has demonstrated a synergistic effect of EEP and antibiotics on the growth of Staphylococcus aureus, and suggested that the bactericidal effect of EEP was expressed mainly on virulent mycobacteria rather than on non-virulent (attenuated)...

We investigated the susceptibility of virulent and avirulent strains of Haemophilus ducreyi to the bactericidal activity of normal human serum and to phagocytosis and killing by human polymorphonuclear leukocytes (PMNL). Strains were defined as virulent if intradermal inoculation into a rabbit produced a typical necrotic lesion. Nonvirulent strains produced no cutaneous lesions in rabbits. Viru...