Authors:Fatemeh Eghbalpoor, Mehri Habibi, Omid Azizi, Mohammad Reza Asadi Karam and Saeid Bouzari
of antibioticresistance [ 4 ]. Capsule is among the main virulence factors of K. pneumoniae isolates for protection against host immune system. K1 and K2 capsular serotypes containing the mucoviscosity-associated gene A ( magA ) were associated
Authors:Balázs Farkas, Eszter Ostorházi, Katinka Pónyai, Béla Tóth, Elmardi Adlan, László Párducz, Márta Marschalkó, Sarolta Kárpáti and Ferenc Rozgonyi
Beeton, M. L., Chalker, V. J., Maxwell, N. C. és mtsai: Concurrent titration and determination of antibioticresistance in Ureaplasma species with identification of novel point mutations in genes associated with resistance. Antimicrob. Agents Chemother
Besides the well-known O157:H7 clone causing enterohaemorrhagic colitis and haemolytic uraemic syndrome in Europe, Japan and North America, the number of Escherichia coli isolates with non-motile (NM) phenotype has considerably increased. We supposed that spontaneous antibiotic resistance mutation could cause this phenotypic change. To model our hypothesis we isolated rifampicin- (Rif) and ampicillin- (Amp) resistant mutants from E. coli O157:H7 prototype strains 7785 and EDL933. Among Rif r mutants we could isolate strains with no or reduced motility, while the Ampr mutants became hypermotile. The biochemical profile of the mutants had not changed but phage sensitivity and generation time of the mutants were altered. Among the representative strains we did not find polymorphism with Southern blot analysis and no polymorphism was found in the fliC gene of the mutants. The described characteristics have proven to be stable. In a mice virulence assay by intravenous infections the virulence of the derivatives was also found to be changed. In summary, we found that the antibiotic-resistant phenotype in E. coli O157:H7 was coexpressed with several other phenotypic changes including motility and virulence. It can be assumed that expression of the involved phenotypes may be under the influence of a common regulatory cascade. Further work is needed to identify the components and mechanism of this regulatory system.
Authors:Abraham Ajayi, Stella Ifeanyi Smith, Julien Coulibaly Kalpy, Ibidunni Oreoluwa Bode-Sojobi, Yao Kouamé René and Adeyemi Isaac Adeleye
and antibioticresistance profiling of Salmonella serovars isolated from humans, chicken, and pigs [ 17 – 19 ] but there is drought of information on studies that evaluates human and a broader range of food animals at once. Hence, this study explores