Risk factors and prognosis of complicated urinary tract infections caused by Pseudomonas aeruginosa in hospitalized patients: a retrospective multicenter cohort study

Purpose

Complicated urinary tract infections (cUTIs) are among the most frequent health-care-associated infections. In patients with cUTI, Pseudomonas aeruginosa deserves special attention, since it can affect patients with serious underlying conditions. Our aim was to gain insight into the risk factors and prognosis of P. aeruginosa cUTIs in a scenario of increasing multidrug resistance (MDR).

Methods

This was a multinational, retrospective, observational study at 20 hospitals in south and southeastern Europe, Turkey, and Israel including consecutive patients with cUTI hospitalized between January 2013 and December 2014. A mixed-effect logistic regression model was performed to assess risk factors for P. aeruginosa and MDR P. aeruginosa cUTI.

Results

Of 1,007 episodes of cUTI, 97 (9.6%) were due to P. aeruginosa. Resistance rates of P. aeruginosa were: antipseudomonal cephalosporins 35 of 97 (36.1%), aminoglycosides 30 of 97 (30.9%), piperacillin-tazobactam 21 of 97 (21.6%), fluoroquinolones 43 of 97 (44.3%), and carbapenems 28 of 97 (28.8%). The MDR rate was 28 of 97 (28.8%). Independent risk factors for P. aeruginosa cUTI were male sex (OR 2.61, 95% CI 1.60-4.27), steroid therapy (OR 2.40, 95% CI 1.10-5.27), bedridden functional status (OR 1.79, 95% CI 0.99-3.25), antibiotic treatment within the previous 30 days (OR 2.34, 95% CI 1.38-3.94), indwelling urinary catheter (OR 2.41, 95% CI 1.43-4.08), and procedures that anatomically modified the urinary tract (OR 2.01, 95% CI 1.04-3.87). Independent risk factors for MDR P. aeruginosa cUTI were age (OR 0.96, 95% CI 0.93-0.99) and anatomical urinary tract modification (OR 4.75, 95% CI 1.06-21.26). Readmission was higher in P. aeruginosa cUTI patients than in other etiologies (23 of 97 [23.7%] vs 144 of 910 [15.8%], P=0.04), while 30-day mortality was not significantly different (seven of 97 [7.2%] vs 77 of 910 [8.5%], P=0.6).

Conclusion

Patients with P. aeruginosa cUTI had characteristically a serious baseline condition and manipulation of the urinary tract, although their mortality was not higher than that of patients with cUTI caused by other etiologies.

Antimetastatic activity of Atu027, a liposomal small interfering RNA formulation, targeting protein kinase N3 (PKN3): Final results of a phase I study in patients with advanced solid tumors

e13597

Background: Atu027 contains siRNA-lipoplexes, which elicits RNAi mediated suppression on PKN3 in vascular endothelial cells. In various xenograft mouse models, silencing of PKN3 expression and significant inhibition of invasive growth, lymph node and pulmonary metastasis formation was shown. Methods: Atu027 was applied to patients (pts) as a single 4h-infusion with subsequent follow-up for 3 wks. Thereafter pts were treated twice weekly for 4 weeks. In case of SD, pts were treated until PD. Dose escalation was associated with assessment of toxicity, pharmacokinetics (PK), and multiplex biomarker analyses in plasma from treated pts. Results: A total of 33 pts have received Atu027 of 11 dose levels (DL) up to 0.336 mg/kg. No pre-medication was required. No cytokine activation (TNF-α, IL-1β, IFN-γ, IL-6) was observed. In some subjects transient activation of the complement system (C3a, Bb, sC5b-9) was found, but without any clinical relevance. PK-data showed dose-dependent increase in plasma siRNA as well as lipid levels. Among various biomarkers tested, sVEGFR-1 plasma levels decreased significantly upon treatment. Across all dose levels, Atu027 was well-tolerated. Adverse events possibly related to Atu027 were fatigue grade G1 (6pts), hair loss G1 (2pts), sweating G1 (1pt), and abdominal pain G2 (1pt). G3 AEs not considered as DLTs were elevated lipase (2 pts, DL2+DL10) and diarrhea (1 pt, DL5). So far, no DLTs were seen in the last DL. Stable disease after 3 and 6 months was observed in 10 and 3 pts, respectively. Two pts with neuroendocrine cancer had disease stabilization for 9 and 12 months, respectively, including partial regression of pulmonary metastases in 1 pt. Another patient with breast cancer had regression of liver metastases. Conclusions: Atu027 is well-tolerated and anti-metastatic activity has been observed. Soluble VEGFR-1 might serve as a biomarker. So far, 0,336 mg/kg is the recommended dose for further phase II trials.

The forskolin-induced opening of tight junctions in Xenopus gallbladder epithelium is mediated by protein kinase C

The effects of protein kinase A (PKA)-mediated and protein kinase C (PKC)-mediated stimulation on the tight junctions of the moderately tight Xenopus gallbladder epithelium have been investigated. Transepithelial impedance and DC voltage divider ratio measurements in Ussing-type chambers were used to calculate the cell membrane and tight junction resistances in the stimulated state. Under control conditions the TE resistance was used as a lowest estimate of tight junction resistance. Stimulation of PKA by forskolin and theophyllin as well as stimulation of PKC by phorbol dibutyrate lowered the TE resistance mainly via the reduction of the tight junctional resistance. PKA stimulation opened, in addition, an apical Cl- selective conductance. The paracellular pathway activated by PKA or PKC did not discriminate between small anions and cations. The effects of PKA stimulation could be blocked by the selective inhibition of PKA (with H89) or of PKC (with bisindolylmaleimide). By contrast the PKC-evoked effects were insensitive to H89, showing that the effects of PKA on the paracellular pathway were mediated by PKC.

The activation of an apical Cl- conductance by extracellular ATP is potentiated by genistein in Necturus gallbladder epithelium

Necturus gallbladder epithelium (NGE) expresses a CFTR-homologous apical Cl- conductance (Ga,Cl) which can be activated either by elevation of intracellular cAMP or by extracellular ATP. Here we show by microelectrode experiments and impedance analysis that genistein (50 microM), which is known to potentiate the stimulation of Ga,Cl in several cell culture models, also potentiates the stimulation of Ga,Cl by low doses of forskolin in NGE. Moreover, we show that genistein also potentiates the stimulation of Ga,Cl by ATP. In addition genistein renders gallbladders that initially do not respond to ATP sensitive to this stimulant, and it delays the conductance inactivation after ATP removal. Under control conditions Ga,Cl inactivates within < 5 min, but in the presence of genistein a significant Ga,Cl persists even after 60 min. These effects of genistein are not related to inhibition of protein tyrosine kinases, since structurally different inhibitors of the tyrphostin family do not mimic the genistein effects. The data support our conclusion that stimulation of Ga,Cl by ATP is mediated by activation of the cAMP pathway and involves a CFTR-homologous protein. They also favour the view that genistein acts via inhibition of protein phosphatases which dephosphorylate CFTR, but cannot exclude the possibility of a direct interaction with CFTR.

Activation of an apical Cl- conductance by extracellular ATP in Necturus gallbladder is mediated by cAMP and not by [Ca2+]i

Necturus gallbladder epithelium (NGE) expresses a CFTR-like apical Cl- conductance that can be activated by cAMP. Here, we show that extracellular ATP (100 microM), which is known to elevate intracellular Ca2+ and to hyperpolarize cells by stimulating apical and basolateral K+ conductances, also stimulates an apical Cl- conductance (Ga,Cl), however with a much slower time course. The selectivity sequence of Ga,Cl was SCN- > I- > NO3- > Br- > Cl- >> isethionate (ISE-), but SCN- and I- partially blocked it, which is analogous to observations of CFTR Cl- channels. To disclose a possible role for intracellular Ca2+, gallbladders were incubated with the Ca2+ chelator BAPTA/AM or bathed in solutions containing only submicromolar Ca2+ concentrations. BAPTA partially inhibited the Ca(2+)-mediated hyperpolarization, but did not reduce the ATP-dependent activation of Ga,Cl and the latter was also seen in low extracellular Ca2+. On the other hand, the cAMP-antagonist Rp-8-Br-cAMPS strongly inhibited the stimulation of Ga,Cl by ATP (as well as by forskolin), but left the ATP-induced hyperpolarization unchanged. Preincubation with a low concentration of forskolin markedly enhanced the stimulatory effect of ATP, and this effect was not modified by the selective inhibition of protein kinase C. These data suggest the involvement of different signal transduction pathways in the ATP-dependent activation of K+ and Cl- conductances in NGE. The stimulation of the Ga,Cl appears to be mediated by cAMP but not by elevation of intracellular Ca2+.