Irina Gheorghe

Snapshot on carbapenemase-producing Pseudomonas aeruginosa and Acinetobacter baumannii in Bucharest hospitals reveals unusual clones and novel genetic surroundings for blaOXA-23

OBJECTIVES The present study was designed to provide a snapshot on carbapenemase-producing Pseudomonas aeruginosa (n=11) and Acinetobacter baumannii (n=7) isolates in hospitalized patients (November 2011, January-March 2012) from two main hospitals in Bucharest, south Romania. METHODS Clonality among isolates was established by PFGE, MLST and Fourier transform infrared spectroscopy. Carbapenemases were screened by the Blue-Carba test, PCR and sequencing. Transferability of blaOXA-23 was tested by conjugation and plasmid typing (number, size and identity) was assessed by S1-PFGE, replicon typing, hybridization and PCR mapping. RESULTS All P. aeruginosa isolates carried chromosomally located blaVIM-2, associated with a common class 1 integron (aacA7-blaVIM-2) or an atypical configuration (aacA7-blaVIM-2-dfrB5-tniC). These isolates belonged to unusual lineages; mostly ST233 disseminated in one hospital unit, with ST364 and ST1074 also being detected. A. baumannii isolates carried blaOXA-23 in Tn2008, which was found truncating a TnaphA6 transposon located in a common 60 kb GR6 (aci6) pABKp1-like conjugative plasmid in highly related CC92 clones (ST437, ST764 and ST765), where CC stands for clonal complex. CONCLUSIONS Our results show the spread of VIM-2-producing P. aeruginosa and OXA-23-producing A. baumannii clinical isolates in two hospitals from Bucharest and highlight a peculiar population structure in this Eastern European country. Also, we demonstrate the dissemination of a common and conjugative aci6 pABKp1-like plasmid scaffold in different A. baumannii clones and we report the first known identification of Tnaph6-carrying pACICU2-like plasmids in Europe.

Caprolactam-silica network, a strong potentiator of the antimicrobial activity of kanamycin against gram-positive and gram-negative bacterial strains.

Here, we report the fabrication of a novel ε-caprolactam-silica (ε-SiO2) network and assessed its biocompatibility and ability to improve the antimicrobial activity of kanamycin. The results of the quantitative antimicrobial assay demonstrate that the obtained ε-SiO2 network has efficiently improved the kanamycin activity on Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 strains, with a significant decrease of the minimum inhibitory concentration. The ε-SiO2 network could be feasibly obtained and represents an alternative for the design of new antibiotic drug carriers or delivery systems to control bacterial infections.

Present and perspectives in pesticides biosensors development and contribution of nanotechnology

A biosensor is an analytical device, used for the detection of an analyte, combining a biological component (bioreceptor represented by biomolecules or synthetic molecules obtained using biological scaffolds) with a physico-chemical detector, as well as an associated electronic system, which amplifies, process, and display the detected signal. Biosensors are used in a wide range of applications for the quick and easy detection of pesticides and water contaminants, such as heavy metal ions, organophosphates, of biological warfare agents, and pathogens, of drug residues in food, determining levels of toxic substances before and after bioremediation, to drug discovery and evaluation of biological activity of new compounds and so on. Anthropic activities generate the release of contaminants, such as pesticides and other pollutants, in soil and the aquatic environment, presenting a real threat to ecosystems and human health. Thus, monitoring tools become essential for water managers to detect these chemicals before the occurrence of adverse effects. The purpose of this chapter is to present the current state and perspectives in the development of pesticides biosensors and the contribution of nanotechnology.

Aspects of Gut Microbiota and Immune System Interactions in Infectious Diseases, Immunopathology, and Cancer

The microbiota consists of a dynamic multispecies community of bacteria, fungi, archaea, and protozoans, bringing to the host organism a dowry of cells and genes more numerous than its own. Among the different non-sterile cavities, the human gut harbors the most complex microbiota, with a strong impact on host homeostasis and immunostasis, being thus essential for maintaining the health condition. In this review, we outline the roles of gut microbiota in immunity, starting with the background information supporting the further presentation of the implications of gut microbiota dysbiosis in host susceptibility to infections, hypersensitivity reactions, autoimmunity, chronic inflammation, and cancer. The role of diet and antibiotics in the occurrence of dysbiosis and its pathological consequences, as well as the potential of probiotics to restore eubiosis is also discussed.

11 – Fate of antibiotics during water treatment: impact on antimicrobial resistance in environmental and clinical strains

Wastewater treatment plants (WWTPs) provide appropriate conditions for the selection of antibiotic resistance (AR), as well as for the exchange of AR genes between pathogenic and environmental bacteria, and further dissemination among members of the endogenous microbial community, due to the presence of antibiotics, high organic content, as well as high microbial density and diversity. The purpose of this chapter is to highlight some aspects regarding the origin, transfer, and accumulation of antibiotic resistance genes in the WWTPs aquatic environment.

Introduction in Soft Chemistry and Food Fermentation

Abstract Biotechnology (term composed of bios and technique ) is based on the industrial exploitation of productive potentiality of microorganisms, plant or animal cells, or their subcellular fractions, to obtain useful products. The progress of general microbiology, biochemistry, molecular biology, and biotechnologies led to a new science, industrial microbiology, and thereby, to industrial exploitation of new potentiality of microorganisms: antibiotic synthesis; enzyme production; production of alcoholic beverages; biofuel production; food preservation; and bioremediation of air, soil, and water contamination. Fermentation, a term derived from the Latin verb fevere (to boil), is one of the oldest methods of processing food and is the most important process in the food industry, playing many roles in the enrichment of the human dietary, food preservation, and biological enrichment of food substrates. Fermentation is a natural process achieved by microorganisms, subsequently used by humans on an industrial scale, but not invented by man. Industrial microbiology use different microorganisms, such as naturally occurring organisms, laboratory selected mutants, or even genetically modified organisms, to produce a very large variety of industrial products for human interest. This chapter provides an overview of general data regarding the fermentation process, industrial microorganisms, and their metabolites, fermented food, and health benefits.

Beta-lactam and quinolone resistance markers in uropathogenic strains isolated from renal transplant recipients

Abstract Our objectives were to investigate the extended-spectrum beta-lactamases (ESBLs) and carbapenemases (CR) genetic determinants and to assess the association between ESBL production and quinolone resistance in bacterial strains isolated from renal transplant recipients with urinary tract infections. Material and methods: A number of 30 isolates were recovered from urine specimens of patients with renal transplant from October 2015 to March 2016. The isolates were analyzed for ESBL production using double disc synergy test and for CR production by the Hodge test. Phenotypically confirmed isolates were screened by PCR for the identification of ESBL, CR and fluoroquinolone resistance genes. Results: The 30 clinical bacterial strains isolated from urinary tract infections in renal transplant recipients were identified as Klebsiella pneumoniae (17), Pseudomonas aeruginosa (7), Morganella morganii (2), Escherichia coli (2), Edwardsiella tarda (1) and Enterobacter cloacae (1). Out of them, 22 isolates were ESBL producers and 20 multi-drug resistant (MDR) (i.e., 13 K. pneumoniae and 7 P. aeruginosa strains). More than half of the ESBL clinical strains (14/22, 63.63%) revealed at least one ESBL gene, the most frequent being blaCTX-M type (18/22, 81.81%), either alone (4/22, 18.18%) or in combination with another ESBL gene (17/22, 77.27%), followed by blaTEM (13/22, 59.09%). The blaOXA-48 was present in 10 isolates (33.33%). The most frequent association of ESBLs and CR genes (5/14, 35.71%) was revealed by blaCTX-M- blaTEM - blaOXA-48, encountered particularly among K. pneumoniae isolates (4/17, 23.52%). The qnrB gene was identified in five strains, i.e. one P. aeruginosa ESBL isolate (expressing the blaCTX-M gene) and four K. pneumoniae ESBL isolates (harboring the blaCTX-M - blaTEM genes combination). Conclusions: The uropathogenic strains isolated from renal transplant recipients exhibited high rates of MDR and beta-lactam resistance. The selective pressure exerted by quinolones could enable uropathogenic bacteria to acquire resistance to this class of antibiotics.

Lessons from inter-regn communication for the development of novel, ecofriendly pesticides

Abstract Pesticides are represented by natural or chemical substances or mixtures of substances used for preventing, destroying, or controlling any pest (virucides, bactericides, fungicides, algaecides, herbicides, desiccants, insecticides, nematicides, molluscicides, rodenticides, avicides, piscicides). Despite their beneficial effects exhibited by the inhibitory effects against pests harmful for plants and animals, the chemical pesticides could also be toxic for other organisms and pollutants for the environment. Biopesticides, which are naturally occurring or derived materials from living organisms or their metabolites, have instead low negative effects as compared to chemical pesticides. Currently, under the pressing issues of food security and the need for implementation of a more sustainable agricultural system globally, there is much interest in the development of new biocontrol agents. The purpose of this chapter was to review the progress made in biopesticides development, focusing on microbial and plant-derived products and in the field of chemical pesticides biodecontamination by using microbial enzymes.

Quantum dots for bioimaging and therapeutic applications

Abstract Offering more advantages compared to the old-fashioned chemical-staining techniques, quantum dots (QD)-mediated imaging has become one of the most explored approaches when it comes to molecular, cellular, and intracellular labeling and biodetection of cytotoxic ions or molecules, organic molecules (DNA, peptides, gluthatione, cancer, cardiac/renal/ocular diseases markers, intracellular markers of various organelles) for biomedical and forensic evaluation, or pH measurements, with extremely low detection limits, upon attomolar range. Optical techniques for biomolecular imaging are being researched intensively and breakthroughs in molecular staining and imaging are being made daily. The fluorescent/phosphorescent emissions are to be factored in according to the nature of the medium in which QDs are employed for specific detection, as being used on a large scale for various immunoassays, fluorescent sensing, in vivo tumor imaging and biomolecule detection, even though certain parameters can disable the QDs sensing mechanisms. Techniques for fluorescence, phosphorescence, respectively, sensitivity and biocompatibility enhancement have been developed for a better biological behavior, in terms of parameter optimization: layer thickness, surface modification, coatings, polymer coupling, doping, crystalline size etc. Regenerative medicine might benefit from the properties of QDs, which are proven to be efficient in stem cells labeling for fluorescent imaging in vivo, with high sensitivity; antitumor and antimicrobial efficiency are also reported. In this chapter, we show also that most of the recently investigated biomedical applications can benefit from green synthesis routes of QDs.

Nanostructures for drug delivery: pharmacokinetic and toxicological aspects

For the past few decades, drug delivery systems have become one of the main research fields of the science community in advanced biomedicine. The concept of nanodrugs and the manufacturing of drug delivery systems itself have met impressive heights. In practice, various types of nanodrug systems are provided, most of them with the drugs encapsulated in variously shaped nanocarries, such as dendrimers, liposomes, micelles, and polymer nanoparticles. Nanodrug systems feature a series of pharmacokinetic advantages, such as targeted drug delivery, superior metabolic stability, and membrane permeability, enhanced bioavailability, and prolonged effects. This novel promising therapeutic approach exhibits a high degree of versatility due to the behavioral variability governed by physicochemical properties, such as size, surface charge, and hydrophilic/hydrophobic character. The purpose of this chapter was to offer a thorough report of the recent progresses and degree of toxicity that could be generated by a number of new medical therapies, with a strong impact on medicine, namely “therapeutic devices” based on nanoparticles.