Characterization of the catecholate indicator strain S. typhimurium TA2700 as an ent fhuC double mutant

Abstract

The Salmonella typhimurium strain TA2700 is a good indicator strain for enterobactin and other catecholate siderophores. It is unable to use hydroxamate siderophores and K-keto-/K-hydroxyacids and is resistant to albomycin, a sideromycin. By using a MudPQ mapping set the hydroxamate uptake mutation in TA2700 was located in the 2^5 Cs region. Using transduction with known markers, the mutation was mapped more precisely near 4 Cs. By complementation with different fhu genes from Escherichia coli, a complementation of the hydroxamate iron utilization phenotype was observed in fhuC-complemented TA2700 only. All fhuC-complemented strains were also sensitive to albomycin. A fhuC transductant of S. typhimurium TA2700 was cross-fed by K-ketoisocaproic acid. By cotransduction with known and unknown markers near 13 Cs an ent mutation of S. typhimurium TA2700 was mapped. z

Resuscitation of Salmonella enterica Serovar Typhimurium and Enterohemorrhagic Escherichia coli from the Viable but Nonculturable State by Heat-Stable Enterobacterial Autoinducer

“…As we reported previously (19), addition of ferrioxamine E to BPW resulted in prolonged periods of resuscitation of S. enterica serovar Typhimurium from highly stressed populations beyond the time when incubation in BPW alone no longer resulted in reactivation. Resuscitation by ferrioxamine E is dependent on siderophore uptake, since recovery of the fhuC mutant TA2700 (16,19), which is unable to transport ferrioxamines, was not enhanced by the presence of ferrioxamine E. Furthermore, for all strains of Salmonella that we have tested, including TA2700, supplementation of BPW with enterobacterial AI resulted in resuscitation of cells in stressed populations for longer periods of time than did ferrioxamine E supplementation (Fig. 1a).…”

“…Thus, we confirmed our previous observation that ferrioxamine E can resuscitate wild-type S. enterica serovar Typhimurium from water microcosms and extended it by demonstrating a similar effect on heat-stressed populations. Since Salmonella strains of subspecies I, II, and IIIb, which include more than 98% of all clinical isolates, (9)(10)(11)(12)(13)(14)(15)(16)(17)(18) possess the high-affinity ferrioxamine uptake and utilization system (9), supplementation with ferrioxamine E can be considered to be semiselective for detection of Salmonella spp. in stressed populations (19).…”

Salmonella typhimurium IroN and FepA Proteins Mediate Uptake of Enterobactin but Differ in Their Specificity for Other Siderophores

“…Our strategy to identify a fepA mutant was therefore to characterize transposon insertions, which are cotransduced with enterobactin biosynthesis genes. A phage lysate of a random bank of S. typhimurium Tn10dTc mutants was transduced into an S. typhimurium mutant (TA2700) which is defective for enterobactin production (17). Transductions were performed by using the high-frequency generalized transducing phage mutant P22HT 105/1 int 201.…”

Bekämpfung bakterieller Infektionen - eine ständige Aufgabe des gesundheitlichen Verbraucherschutzes

“…ders gut zur Charakterisierung dieser Catecholaterezeptoren, da es sich um eine ent (enterobactin negativ), fhuC-Mutante handelt, in der die Eisenaufnahme durch Hydroxamate und α-Ketosäuren unterbunden ist [3]. Es wurden alle Rezeptorkombinationsmutanten durch P22HT-Transduktion konstruiert.…”

“…Mittels Feindifferenzierung, besonders der Lysotypie, wurde nachgewiesen, daß epidemiologische Zusam-gegenüber den Vorjahren weiter angestiegen ist[3]. Die Anzahl Infektionen von S. Typhimurium von 1996 zu 1997 ist um ca.…”