First Isolation and Clinical Case of Brevundimonas diminuta in a Newborn with Low Birth Weight, in Democratic Republic of Congo: A Case Report

Brevundimonas diminuta is rarely described in clinical specimens, never at the umbilical stump. Most of the reported cases are in patients with underlying pathologies. We must integrate this microorganism in the etiological agents of nosocomial infections, but much remains to be understood about its virulence. We present a case of umbilical stump infection (omphalitis) caused by B. diminuta, in a preterm and hypotrophic new-born and discuss the diagnosis of this bacterium and its role as responsible of nosocomial neonatal infections.

Brevundimonas diminuta coinfection as source of pyogenic liver abscess

Brevundimonas diminuta, a non-fermenting gram-negative bacterium, is emerging as an important multidrug resistant opportunistic pathogen. It has been described in cases of bacteremia, pleuritis, keratitis and peritoneal dialysis-associated peritonitis. We describe, for the first time, a case of pyogenic liver abscess caused by coinfection of B. diminuta and Streptococcus anginosus, and briefly review pyogenic liver abscesses and the literature regarding B. diminuta.

Thermo-Stable Alkaline Protease Purified from a Novel Endophyte Brevundimonas diminuta VKB1 Hosted in Carica papaya L. – Production Enrichment Approach

Protease is the central component of enzymes in all lives, from microbes to humans. Their limited applications in the medicinal field demand their need for higher production. Our study enlightens protease's sustainable production using various optimization techniques and purification of the protease purified from Carica papaya L's endophytes. The results depict that the protease synthesis was enhanced to five-fold concentration after optimization of the production media. The purified protease was a single protein showing high stability towards alkaline pH and thermo-stable. The metal ions' influence indicates that the protease can be catalyzed highly in the presence of copper, magnesium, iron atoms. Results disclose the purified protease further can be taken for pharmacological studies to understand their efficiency as a therapeutic regime.

Treatment of white water with combined predominant bacteria and immobilized enzyme

White water treatment with combined predominant bacterial species and immobilized enzyme was investigated. The use of the single predominant bacteria of Brevundimonas diminuta or Virgibacillus pantothenticus resulted in poor treatment responses. With the combined bacterial species, the treatment effect was clearly improved. When the dosage ratio of Brevundimonas diminuta to Virgibacillus pantothenticus was 1:2, the chemical oxygen demand (CODCr) removal rate reached 70.5%, the cationic demand decreased 46.0%, and the electrical conductivity decreased 18.6% after 16 h of treatment. When mixed with the immobilized enzyme, the treatment efficiency increased with the immobilized pectinase dosage. When 8 g/L immobilized pectinase was added, the treatment time was shortened from 16 h to 4 h, the highest removal rate of CODCr was 74.1%, the cationic demand decreased 68.7%, and the electrical conductivity in the white water decreased 30.1%. The results indicated that the combination of predominant bacterial species and immobilized pectinase could greatly improve the treatment efficiency of white water.

Steady-State Kinetics of Enzyme-Catalyzed Hydrolysis of Echothiophate, a P–S Bonded Organophosphorus as Monitored by Spectrofluorimetry

Enzyme-catalyzed hydrolysis of echothiophate, a P–S bonded organophosphorus (OP) model, was spectrofluorimetrically monitored, using Calbiochem Probe IV as the thiol reagent. OP hydrolases were: the G117H mutant of human butyrylcholinesterase capable of hydrolyzing OPs, and a multiple mutant of Brevundimonas diminuta phosphotriesterase, GG1, designed to hydrolyze a large spectrum of OPs at high rate, including V agents. Molecular modeling of interaction between Probe IV and OP hydrolases (G117H butyrylcholinesterase, GG1, wild types of Brevundimonas diminuta and Sulfolobus solfataricus phosphotriesterases, and human paraoxonase-1) was performed. The high sensitivity of the method allowed steady-state kinetic analysis of echothiophate hydrolysis by highly purified G117H butyrylcholinesterase concentration as low as 0.85 nM. Hydrolysis was michaelian with Km = 0.20 ± 0.03 mM and kcat = 5.4 ± 1.6 min−1. The GG1 phosphotriesterase hydrolyzed echothiophate with a high efficiency (Km = 2.6 ± 0.2 mM; kcat = 53400 min−1). With a kcat/Km = (2.6 ± 1.6) × 107 M−1min−1, GG1 fulfills the required condition of potential catalytic bioscavengers. quantum mechanics/molecular mechanics (QM/MM) and molecular docking indicate that Probe IV does not interact significantly with the selected phosphotriesterases. Moreover, results on G117H mutant show that Probe IV does not inhibit butyrylcholinesterase. Therefore, Probe IV can be recommended for monitoring hydrolysis of P–S bonded OPs by thiol-free OP hydrolases.