Factors associated with mortality in Infections caused by Carbapenem-resistant Enterobacteriaceae.

INTRODUCTION: There is little information about weigh of factors possibly associated with mortality, in infections caused by Carbapenem-resistant Enterobacteriaceae (CRE) in Latin America. METHODOLOGY: A case-controls study nested in a historical cohort was performed including all patients with CRE infections diagnosed between June 2013 and December 2018 at Hospital Universitario San Ignacio in Bogotá, Colombia. Univariate and multivariate analysis were performed to compare cases of mortality within the first month after the infection diagnosis with surviving patients. RESULTS: A total of 131 patients were included. The overall 30-day mortality rate was 38.17%. In the multivariate analysis, a direct association was found between mortality and septic shock (OR 26.7 CI6.6-107.3 p < 0.01), post-chemotherapy febrile neutropenia (OR 3.3 CI1.06-10.8 p = 0.04) and Charlson Index ≥ 3 (OR 5.5 CI 1.5-20.06 p < 0.01). An inverse association was found with interventions to control the infectious focus (OR 0.3 CI0.1-0.7 p < 0.01). The MIC of different antibiotics and the use of combined antibiotic therapy (triple therapy vs. double therapy or monotherapy) were not associated with mortality. CONCLUSIONS: In patients with CRE infections, septic shock, a Charlson comorbidity index ≥ 3, and post-chemotherapy febrile neutropenia are independently related to an increase in mortality. The control of the infectious focus is a protective factor. A rapid identification of these patients, and the implementation of measures to control infectious focus and to detect CRE colonization in patients who are going to be taken to myelosuppressive chemotherapy could impact positively the prognosis of these patients.

Identification of dehydroabietc acid from Boswellia thurifera resin as a positive GABAA receptor modulator.

In a two-microelectrode voltage clamp assay with Xenopus laevis oocytes, a petroleum ether extract (100 µg/mL) of the resin of Boswellia thurifera (Burseraceae) potentiated GABA-induced chloride currents (IGABA) through receptors of the subtype α1ß2γ2s by 319.8% ± 79.8%. With the aid of HPLC-based activity profiling, three known terpenoids, dehydroabietic acid (1), incensole (2), and AKBA (3), were identified in the active fractions of the extract. Structure elucidation was achieved by means of HR-MS and microprobe 1D/2D NMR spectroscopy. Compound 1 induced significant receptor modulation in the oocyte assay, with a maximal potentiation of IGABA of 397.5% ± 34.0%, and EC50 of 8.7 µM ± 1.3 µM. This is the first report of dehydroabietic acid as a positive GABAA receptor modulator.

Identification of dihydrostilbenes in Pholidota chinensis as a new scaffold for GABAA receptor modulators.

A dichloromethane extract of stems and roots of Pholidota chinensis (Orchidaceae) enhanced GABA-induced chloride currents (I(GABA)) by 132.75 ± 36.69% when tested at 100 µg/mL in a two-microelectrode voltage clamp assay, on Xenopus laevis oocytes expressing recombinant α1ß2γ2S GABA(A) receptors. By means of an HPLC-based activity profiling approach, the three structurally related stilbenoids coelonin (1), batatasin III (2), and pholidotol D (3) were identified in the active fractions of the extract. Dihydrostilbene 2 enhanced I(GABA) by 1512.19 ± 176.47% at 300 µM, with an EC50 of 52.51 ± 16.96 µM, while compounds 1 and 3 showed much lower activity. The relevance of conformational flexibility for receptor modulation by stilbenoids was confirmed with a series of 13 commercially available stilbenes and their corresponding semisynthetic dihydro derivatives. Dihydrostilbenes showed higher activity in the oocyte assay than their corresponding stilbenes. The dihydro derivatives of tetramethoxy-piceatannol (12) and pterostilbene (20) were the most active among these derivatives, but they showed lower efficiencies than compound 2. Batatasin III (2) showed high efficiency but no significant subunit specificity when tested on the receptor subtypes α1ß2γ2s, α2ß2γ2s, α3ß2γ2s, α4ß2γ2s, α5ß2γ2s, α1ß1γ2s, and α1ß3γ2s. Dihydrostilbenes represent a new scaffold for GABA(A) receptor modulators.

Phytochemical profiling of Curcuma kwangsiensis rhizome extract, and identification of labdane diterpenoids as positive GABAA receptor modulators.

An ethyl acetate extract of Curcuma kwangsiensis S.G. Lee & C.F. Liang (Zingiberaceae) rhizomes (100 µg/ml) enhanced the GABA-induced chloride current (IGABA) through GABAA receptors of the α1ß2γ2S subtype by 79.0±7.0%. Potentiation of IGABA was measured using the two-microelectrode voltage-clamp technique and Xenopus laevis oocytes. HPLC-based activity profiling of the crude extract led to the identification of 11 structurally related labdane diterpenoids, including four new compounds. Structure elucidation was achieved by comprehensive analysis of on-line (LC-PDA-ESI-TOF-MS) and off-line (microprobe 1D and 2D NMR) spectroscopic data. The absolute configuration of the compounds was established by comparison of experimental and calculated ECD spectra. Labdane diterpenes represent a new class of plant secondary metabolites eliciting positive GABAA receptor modulation. The highest efficiency was observed for zerumin A (maximum potentiation of IGABA by 309.4±35.6%, and EC50 of 24.9±8.8 µM).

A hypomorphic mutation in the Gfi1 transcriptional repressor results in a novel form of neutropenia.

Using N-ethyl-N-nitrosourea-induced mutagenesis, we established a mouse model with a novel form of neutropenia resulting from a point mutation in the transcriptional repressor Growth Factor Independence 1 (Gfi1). These mice, called Genista, had normal viability and no weight loss, in contrast to mice expressing null alleles of the Gfi1 gene. Furthermore, the Genista mutation had a very limited impact on lymphopoiesis or on T- and B-cell function. Within the bone marrow (BM), the Genista mutation resulted in a slight increase of monopoiesis and in a block of terminal granulopoiesis. This block occurred just after the metamyelocytic stage and resulted in the generation of small numbers of atypical CD11b(+) Ly-6G(int) neutrophils, the nuclear morphology of which resembled that of mature WT neutrophils. Unexpectedly, once released from the BM, these atypical neutrophils contributed to induce mild forms of autoantibody-induced arthritis and of immune complex-mediated lung alveolitis. They additionally failed to provide resistance to acute bacterial infection. Our study demonstrates that a hypomorphic mutation in the Gfi1 transcriptional repressor results in a novel form of neutropenia characterized by a split pattern of functional responses, reflecting the distinct thresholds required for eliciting neutrophil-mediated inflammatory and anti-infectious responses.

Discovery of GABA(A) receptor modulator aristolactone in a commercial sample of the Chinese herbal drug "Chaihu" (Bupleurum chinense roots) unravels adulteration by nephrotoxic Aristolochia manshuriensis roots.

In a two-microelectrode voltage clamp assay using Xenopus laevis oocytes, a petroleum ether extract prepared from a commercial sample of the traditional Chinese herbal drug labelled as " Chaihu" (Bupleurum chinense DC. roots) enhanced the I(GABA) by 156 % ± 22 % when tested at 100 µg/mL. By means of HPLC-based activity profiling combined with high-resolution LC-MS and microprobe NMR, the germacranolide aristolactone was identified as one of the main active compounds (EC50 56.02 µM ± 5.09 µM). However, aristolactone has been previously reported only from the genus Aristolochia (Aristolochiaceae), suggesting a possible adulteration. With the aid of a validated HPTLC protocol for detection of aristolochic acids and with reference samples, the commercial sample was confirmed to be a mixture of Aristolochia manshuriensis root and Bupleurum chinense root. This finding was corroborated by macroscopic inspection of the drug. This case of adulteration with a highly nephrotoxic drug raises concerns about adequate quality control of TCM drugs commercialized in Europe.

HPLC-based activity profiling of Angelica pubescens roots for new positive GABAA receptor modulators in Xenopus oocytes.

A petroleum ether extract of the traditional Chinese herbal drug Duhuo (roots of Angelica pubescens Maxim. f. biserrata Shan et Yuan), showed significant activity in a functional two-microelectrode voltage clamp assay with Xenopus oocytes which expressed recombinant γ-aminobutyric acid type A (GABA(A)) receptors of the subtype α(1)ß(2)γ(2S). HPLC-based activity profiling of the active extract revealed six compounds responsible for the GABA(A) receptor modulating activity. They were identified by microprobe NMR and high resolution mass spectrometry as columbianetin acetate (1), imperatorin (3), cnidilin (4), osthol (5), and columbianedin (6). In concentration-dependent experiments, osthol and cnidilin showed the highest potentiation of the GABA induced chloride current (273.6%±39.4% and 204.5%±33.2%, respectively at 300 µM). Bisabolangelone (2) only showed minor activity at the GABA(A) receptor. The example demonstrates that HPLC-based activity profiling is a simple and efficient method to rapidly identify GABA(A) receptor modulators in a bioactive plant extract.