Naslov
The Strong Growth Advantage in Stationary Phase Phenomenon in Mixed Cultures of Antimicrobial Resistant Escherichia and Salmonella

Autori
Bačun-Družina, Višnja ; Butorac, Ana, Halec, Ivana ; Gjuračić, Krešimir

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of abstracts / - , 2008, A-24

Skup
EhrlichII- 2nd World Conference on Magic Bullets

Mjesto i datum
Nürnberg, Njemačka, 03.10.2008. - 05.10.2008

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Strong GASP phenotype; Escherichia coli; Salmonella enterica

Sažetak
Background: During prolonged stationary phase, mutants with increased fitness express growth advantage in stationary phase” (GASP) enabling them to grow and displace the parent as the majority population. Aims: 1) To study the GASP phenotype in mixed cultures of Escherichia coli and Salmonella enterica serovar typhimurium wild type and strains harboring either the resistance to nalidixic acid (NalR) or to streptomycin (StrR). 2). To evaluate the influence of multidrug resistance on the appearance of GASP phenotype. 3) To detect if there are genomic differences between both aged wild-type and used resistant mutants (StrR and NalR) of E. coli, the pulsed-field gel electrophoresis (PFGE) of total genomic DNA was conducted. Methods: In a typical GASP competition experiment, cells from a 10-day-old culture are inoculated as a numerical minority (1:100 vol/vol) into a young (1-day-old) culture. The genomic DNA from randomly chosen colonies was digested with SfiI and resolved by pulsed-field gel electrophoresis (PFGE). Results: In the mixture consisting of the aged S. enterica StrR and young E. coli NalR, strong phenotype GASP mutants of S. enterica dominated after the third day of mutual growth. Likewise, but with inversed bacterial resistance, in the mixture of 10-day-old S. enterica NalR culture with young culture of E. coli StrR, the S. enterica NalR GASP mutants of strong phenotype dominated the mixture after the fifth day and were maintained at about 1x108 CFU/ml. Electrophoretic karyotype of the 10-days-old GASP mutants of E. coli strains carrying the resistance revealed additional bands when compared to the wild-type. Conclusions: 1) The strong GASP phenotype was obtained in mixed cultures with the aged mutant strains, but not when the isogenic antibiotic-sensitive strains were used. 2) The cells in mixed cultures of double mutant E. coli strain NalR ValR bear multiple useful GASP mutations that increase its fitness in comparison with mutants E. coli strain StrR and S. enterica strain StrR and showed strong GASP phenotype. 3) The PFGE analysis demonstrated the significant chromosomal rearrangements in 10-day-old bacterial antibiotic-resistant mutated cells that correspond with the appearance of strong GASP phenomenon.

Izvorni jezik
Engleski

Znanstvena područja
Biotehnologija

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