Acute Kidney Injury related to intravenous Colistin Use in Lebanese Hospitalized Patients: Incidence and Associated Factors

Introduction: Colistin use has risen because of the emergence of Gram-negative resistant infections. Acute kidney injury (AKI) remains a treatment-limiting factor for widespread colistin clinical use. This study aimed to determine the incidence and the factors associated with the development of colistin-induced AKI. Method: A retrospective observational study was conducted by reviewing files of adult patients, with normal kidneys function between January 2015 to March 2019 at a university hospital located in Beirut city. AKI was defined based on KDIGO criteria. Several variables were tested to determine independent factors that were associated with colistin induced AKI. Results: A total of 113 patients were included in this study. AKI occurred in 53 patients (46.9%). The Charlson Comorbidity Index (CCI) was significantly higher in the AKI group (2.26, P-value = 0.026). In the multivariate analysis, low serum albumen was found as an independent significant predictor for AKI (OR=.065, 95%CI: .013-.337, P-value=0.001). Moreover, the risk for AKI increased by 2 folds (OR=2.019, 95%CI: 1.094-3.728, P-value: 0.025), when two or more nephrotoxic agents were administered simultaneously with colistin. Patient’s age was also found as significant predictor for AKI (OR=1.034, 95% CI:1-1.07), with a cut-off value of 58.5 year-old. Conclusion: This study demonstrated that the use of concomitant use of two or more nephrotoxic drugs, patient’s age of 58.5 or more, and the presence of hypoalbuminemia were independent factors for the development of colistin-induced AKI. These factors should be therefore taken into consideration when prescribing colistin in clinical practice to reduce the risk of AKI.

PEMBUATAN NANOPARTIKEL ALBUMIN MENGGUNAKAN METODE DESOLVASI SEBAGAI ALTERNATIF SISTEM PEMBAWA

Desolvasi merupakan teknik pembuatan nanopartikel berdasarkan perbedaan kelarutan antara desolvating agent dengan pelarut air yang bercampur BSA. Tujuan dari penelitian ini adalah mengembangkan teknik desolvasi untuk pembuatan nanopartikel. berbahan Bovine Serum Albumen (BSA) dengan metode desolvasi. Parameter yang diuji adalah optimasi penggunaan beberapa macam bahan desolvating agent, jumlah BSA, jumlah desolvating agent, lama waktu pengadukan, dan pH dari pelarut. Nanopartikel BSA. Hasil yang didapat menunjukkan bahwa nanopartikel BSA terbaik adalah nanopartikel BSA yang menggunakan 4 mL aseton sebagai desolvating agent dan 30 mg BSA 30 mg dalam 2 mL pelarut air, dengan waktu pengadukan selama 3 jam dan pH 9.

Synthesis and Characterization of Mercapturic Acid (N-acetyl-L-cysteine)-Aflatoxin B1 Adduct and Its Quantitation in Rat Urine by an Enzyme Immunoassay

A simple and sensitive indirect noncompetitive enzyme immunoassay to quantitate mercapturic acid-aflatoxin B1 (AFB1) adduct in rat urine is reported. A novel procedure was developed for in vitro synthesis of an immunogen, bovine serum albumen-glutathione-aflatoxin B1 (BSA-GSH-AFB1) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride. Sulphydryl group's analysis confirmed the conjugation of SH groups to AFB1. Thin-layer chromatography and spectral analysis (absorption, fluorescence, and Fourier transform infrared) of the conjugates further confirmed the formation of the adducts. Polyclonal antibodies specific to mercapturic acid-AFB1 adduct were produced against BSA-GSH-AFB1. The assay was found to be linear in the range of 100 pg100 ng of the analyte (y ab x). A 50 displacement of BSA-GSH-AFB1 antibodies was achieved at an inhibitory concentration (IC50)of 11.9 ng GSH-AFB1 (r2 0.98) and 1.22 ng N-acetyl-L-cysteine (NAC)-AFB1 (r2 0.98). Spiking 5 g/mL of reference standard to the control rat urine showed a recovery of 98 2. The immunoassay was validated in a rodent model exposed to a single oral dose of 1 mg/kg body mass of pure AFB1. The excretion of NAC-AFB1 adduct was quantitated at the end of 24 h. The concentration of the NAC-AFB1 adduct excreted in urine as determined by the immunoassay was found to be in the range of 3.225.97 g/mg creatinine. The present method may find wide application as a biochemical tool in molecular epidemiological and intervention studies with respect to human exposure to dietary aflatoxins.

aro Mutations in Salmonella enterica Cause Defects in Cell Wall and Outer Membrane Integrity

ABSTRACT In this study we characterized aro mutants of Salmonella enterica serovars Enteritidis and Typhimurium, which are frequently used as live oral vaccines. We found that the aroA, aroD, and aroC mutants were sensitive to blood serum, albumen, EDTA, and ovotransferrin, and this defect could be complemented by an appropriate aro gene cloned in a plasmid. Subsequent microarray analysis of gene expression in the aroD mutant in serovar Typhimurium indicated that the reason for this sensitivity might be the upregulation of murA. To confirm this, we artificially overexpressed murA from a multicopy plasmid, and this overexpression caused sensitivity of the strain to albumen and EDTA but not to serum and ovotransferrin. We concluded that attenuation of aro mutants is caused not only by their inability to synthesize aromatic metabolites but also by their defect in cell wall and outer membrane functions associated with decreased resistance to components of innate immune response.

Influence of Variations in Methodology on Populations of Listeria monocytogenes Recovered from Lettuce Treated with Sanitizers

The elimination of Listeria monocytogenes inoculated onto a piece of cut iceberg lettuce (3.8 by 3.8 cm) by treatment with chlorinated water (200 μg/ml free chlorine) and a 0.5% (wt/vol) solution of FIT Professional Line Antibacterial Cleaner (FIT) was investigated. The efficacy of the two sanitizers was not influenced by the composition of the medium used to culture the L. monocytogenes used in the inocula, the number of strains in the inoculum, or the recovery medium used to enumerate the pathogen on lettuce after treatment. Drying inoculum on lettuce for 45 min at 37°C caused more cells to die or not be retrieved compared with drying inoculum for 30 min at 25°C. However, the percentage of cells in the inoculum recovered from lettuce treated with chlorine or FIT was not significantly different, regardless of the drying method. Stomaching, homogenizing, or stomaching followed by homogenizing lettuce treated with sanitizers resulted in recovery of similar numbers of L. monocytogenes, indicating that stomaching and homogenizing are equivalent in extracting cells; the sequential use of both processing methods did not substantially increase the efficiency of recovery. Washing lettuce with water or treating lettuce with 200 μg/ml chlorine or FIT resulted in decreases in populations of 0.60, 1.76, and 1.51 log CFU per lettuce piece, respectively, regardless of variations in test parameters. Reductions caused by sanitizers were significantly greater (α = 0.05) than that observed for water but not significantly different from each other. It is concluded that evaluation of sanitizers for their efficacy in killing L. monocytogenes on lettuce can be determined by spot inoculating 50 μl of a five-strain mixture of cells from 24-h cultures suspended in 5% horse serum albumen, followed by drying the inoculum for 45 min at 37°C, treatment by submerging in 50 ml of sanitizer for 5 min, stomaching samples in 50 ml of Dey-Engley neutralizing broth for 2 min, and enumerating survivors on modified Oxford medium.

Inorganic and organic substrates as sources of nitrogen and phosphorus for multiple genotypes of two ericoid mycorrhizal fungal taxa from Woollsia pungens and Leucopogon parviflorus (Ericaceae)

The abilities of six genotypes of two putative Helotiales ascomycete ericoid mycorrhizal fungal taxa from Woollsia pungens Cav. (Muell.) and Leucopogon parviflorus (Andr.) Lindl. (Ericaceae) to utilise a range of nitrogen and phosphorus compounds for growth were tested in axenic liquid culture. Although significant intra- and interspecific variation was observed, genotypes of both taxa utilised NH4+, NO3–, a range of acidic, neutral and basic amino acids and bovine serum albumen as sole nitrogen sources, along with orthophosphate, inositol hexaphosphate and DNA as sole phosphorus sources. For several isolates of each taxon, growth on the sulfur-containing amino acid cysteine was increased significantly when other forms of sulfur were excluded from the growth medium, suggesting that cysteine utilisation may represent a sulfur-scavenging strategy. Pooled data for all genotypes indicated that Taxon II produced significantly greater biomass on most substrates; however, in no case did this differ by an order of magnitude or more. Both taxa thus appear likely to have broadly similar abilities to obtain nitrogen and phosphorus from organic substrates on soil.