Severe diarrhoea caused by highly ciprofloxacin-susceptible Campylobacter isolates

AbstractThe impact of fluoroquinolone resistance of Campylobacter jejuni and Campylobacter coli isolates on the outcome of the disease in sporadic Campylobacter infections of Finnish individuals was studied. Questionnaires were sent, during a 6-month study period, to patients who were stool culture-positive for Campylobacter spp. In total, 192 returned questionnaires were analysed and assessed, together with the susceptibility data of the respective bacterial isolates. Only one (2%) of the domestic, but half of the imported, Campylobacter isolates were resistant to ciprofloxacin. Ciprofloxacin resistance was not associated with particularly severe infection. Instead, ciprofloxacin-susceptible Campylobacter isolates, as compared to ciprofloxacin-resistant isolates, showed a tendency to cause more severe infections, characterized by bloody stools and hospitalization

Differential regulation of SOCS genes in normal and transformed erythroid cells

The SOCS family of genes are negative regulators of cytokine signalling with SOCS-1 displaying tumor suppressor activity. SOCS-1, CIS and SOCS-3 have been implicated in the regulation of red blood cell production. In this study, a detailed examination was conducted on the expression patterns of these three SOCS family members in normal erythroid progenitors and a panel of erythroleukemic cell lines. Unexpectedly, differences in SOCS gene expression were observed during maturation of normal red cell progenitors, viz changes to CIS were inversely related to the alterations of SOCS-1 and SOCS-3. Similarly, these SOCS genes were differentially expressed in transformed erythoid cells erythroleukemic cells immortalized at an immature stage of differentiation expressed SOCS-1 and SOCS-3 mRNA constitutively, whereas in more mature cell lines SOCS-1 and CIS were induced only after exposure to erythropoietin (Epo). Significantly, when ectopic expression of the tyrosine kinase Lyn was used to promote differentiation of immature cell lines, constitutive expression of SOCS-1 and SOCS-3 was completely suppressed. Modulation of intracellular signalling via mutated Epo receptors in mature erythroleukemic lines also highlighted different responses by the three SOCS family members. Close scrutiny of SOCS-1 revealed that, despite large increases in mRNA levels, the activity of the promoter did not alter after erythropoietin stimulation; in addition, erythroid cells from SOCS-1-/- mice displayed increased sensitivity to Epo. These observations indicate complex, stage-specific regulation of SOCS genes during normal erythroid maturation and in erythroleukemic cells