this reduction in use. The first period of media PBTZ 169 coverage of regulatory warnings was associated with a temporal dip in citalopram, and sertraline use in pediatrics, and adolescents in NL. Similar reductions in SSRI use by children and adolescents were also reported in other countries.. However, our data demonstrate that this temporal decrease in use by Dutch children and adolescent user groups recovered between the first and second period of media coverage of regulatory warnings. These results may indicate that doctors outweighed the benefits of SSRIs compared to the risks. Wijlaars et al. have reported similar longterm use patterns for British children, but without systematically accounting for the effects of the media coverage of the warnings, or differential antidepressant use by various young age groups. Conclusion The timing of the media coverage of regulatory warnings about the suicidality risk associated with 
SSRI use coincided with changes in overall use in the NL and UK from 20002010. The results of this study demonstrate that short-term investigations only provide a snapshot of the potential implications of media coverage and regulatory warnings. We confirmed a strong, but not causal, association between periods of intense media coverage of regulatory warnings and significant changes in SSRI use over a ten-year period in both countries. However, our long-term assessment illustrated that the changes were temporal, drugspecific and more pronounced in pediatrics and young adults. The twofold increase in SSRI use over the 10-year period indicates that regulatory warnings and media coverage may come and go, but they do not have a significant impact on the overall upward trend of SSRI use as a drug class in both countries. Proteus mirabilis is an important pathogen of the urinary tract, and is the primary infectious agent in patients with indwelling urinary catheters. Several potential virulence factors may be responsible for the pathogenicity of P. mirabilis. Among them, flagella, necessary for swarming, are involved in establishing infection. Haemolysin, which is cytotoxic for cultured urinary tract epithelial cells, has been shown to be correlated with the ability of bacteria to invade cells. The ability of P. mirabilis to express virulence factors, such as haemolysin, and to invade urothelial cells, is coordinately regulated with swarming differentiation. Characterization of Proteus mutants has indicated that a substantial number of proteins, including FlhD2C2, RsbA and RsmA, are involved in regulation of swarming and virulence factor expression. Among these regulatory proteins, RcsD has been shown to act as a negative regulator of swarming differentiation and virulence factor expres- sion in P. mirabilis. In Escherichia coli, the RcsCDB signal transduction system consists of three proteins: the sensor RcsC, the cognate response regulator RcsB and the histidinecontaining phosphotransfer protein RcsD. It has been determined that the flow of phosphoryl groups through the Rcs phosphorelay components occurs as follows: RcsC RcsD RcsB. This Rcs system appears to be conserved in the family Enterobacteriaceae, and it is involved in controlling the transcription of a vast range of genes, such as those regulating flagellum synthesis, O-antigen chain length, and virulence. It is noteworthy that the Rcs system negatively regulates the transcription of the flhDC flagellar master switch in E. coli, Salmonela and P. mirabilis. FlhD2C2 is nec