Reports in the literature, recently reviewed by Mussgay (8), contain numerous examples of alterations in the properties of arboviruses as a result of their passage in various host systems. Countless other observations of this type undoubtedly have been made but not reported. Early accounts of alterations in virulence of yellow fever virus (YFV) as a result of propagation in vitro have been desc...

The aim of the current study was to determine the virulence factors, serogroups, and antibiotic resistance properties of Shiga toxin-producing Escherichia coli isolated from chicken meat samples. A total of 422 chicken meat samples were collected from 5 townships of Iran. Specimens were immediately transferred to the laboratory in a cooler with an ice pack. Samples were cultured, and the positi...

conclusions: high percentage of hemolysins, biofilm and beta lactamase production by isolated staphylococci, suggests an important role of these virulence factors in the pathogenesis of isolated staphylococci from dermatitis lesions. the s. aureus isolates from wound infections, show a high sensitivity pattern to all examined antibiotics. only ciprofloxacin was found to be active against all is...

background putative virulence factors are responsible for the pathogenicity of utis caused by pseudomonas aeruginosa (p. aeruginosa). resistance of p. aeruginosa to commonly used antibiotics is caused by the extreme overprescription of those antibiotics. objectives the goal of the present study was to investigate the prevalence of virulence factors and the antibiotic resistance patterns of p. a...

  In the present study, the effect of the high and low virulence S. iniae strains on oxidative activity and cytotoxic effects of trout spleen macrophages were studied. Spleen macrophages were collected from trout. Luminol was used as chemiluminigenic probe. Phorbolmyristate acetate (PMA) also was used as positive control activating agent of respiratory burst and significantly stimulated pr...

OBJECTIVE The presence of enterobacteria such as Escherichia coli in the vagina of normal women is not synonymous with infection. However, vaginal E. coli may also cause symptomatic infections. We examined bacterial virulence properties that may promote symptomatic female reproductive tract infections (RTI) and neonatal sepsis. METHODS E. coli isolated as the causative agent from cases of vag...

Pigs were exposed to three passages of the NADC-8 strain of porcine reproductive and respiratory syndrome virus (PRRSV) to investigate the relationship between genotypic and phenotypic properties. Differences were found in the virulence of the three passages called virulent, intermediate, and avirulent. Avirulent virus was derived by attenuation of virulent virus in cell culture and intermediat...