In vivo expression of the heat stable (estA) and heat labile (eltB) toxin genes of enterotoxigenic Escherichia coli (ETEC).
Enterotoxigenic Escherichia coli (ETEC) colonize the intestine and adhere to the epithelium by means of different host specific colonization factors (CFs). Colonizing ETEC produce one or both of two enterotoxins; the heat stable (ST) and heat labile (LT) toxins which are both able to cause diarrhoea. The regulation of virulence genes in ETEC during infection of the human intestine is mainly unknown. In this study we analysed the level of mRNA expression of estA, coding for ST, and eltB, coding for the B subunit of LT, during human infection. The expressions of the toxins in ETEC strains expressing both ST and LT were investigated in bacteria isolated directly from patient stool without sub-culturing, (in vivo) and compared to the expression pattern of the corresponding ST/LT strains grown in liquid broth (in vitro) by quantitative competitive RT-PCR using fluorescent primers. We found that estA and eltB are expressed in the in vivo samples but no significant up-or down regulation of the expression levels of either estA or eltB could be determined in vivo as compared to in vitro.
Sjöling
Asa
A
Institute of Biomedicine, Department of Microbiology and Immunology, Göteborg University, Box 435, 405 30 Göteborg, Sweden. asa.sjoling@microbio.gu.se
Qadri
Firdausi
F
Nicklasson
Matilda
M
Begum
Yasmin Ara
YA
Wiklund
Gudrun
G
Svennerholm
Ann-Mari
AM
D000222:Adaptation, Physiological; D001427:Bacterial Toxins / Q000096:biosynthesis / Q000235:genetics*; D003967:Diarrhea / Q000382:microbiology; D004768:Enterotoxins / Q000096:biosynthesis / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D004927:Escherichia coli Infections / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000235:genetics*; D005243:Feces / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014774:Virulence; D037521:Virulence Factors / Q000096:biosynthesis
D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D037521:Virulence Factors; C034151:heat stable toxin (E coli); C027538:heat-labile enterotoxin, E coli