Microbes and cancer: friends or faux?

Cancer is one of the most aggressive and deadly diseases in the world, representing the second leading cause of death. It is a multifactorial disease, in which genetic alterations play a key role, but several environmental factors also contribute to its development and progression. Infections induced by certain viruses, bacteria, fungi and parasites constitute risk factors for cancer, being chronic infection associated to the development of certain types of cancer. On the other hand, susceptibility to infectious diseases is higher in cancer patients. The state of the host immune system plays a crucial role in the susceptibility to both infection and cancer. Importantly, immunosuppressive cancer treatments increase the risk of infection, by decreasing the host defenses. Furthermore, alterations in the host microbiota is also a key factor in the susceptibility to develop cancer. More recently, the identification of a tumor microbiota, in which bacteria establish a symbiotic relationship with cancer cells, opened a new area of research. There is evidence demonstrating that the interaction between bacteria and cancer cells can modulate the anticancer drug response and toxicity. The present review focuses on the interaction between microbes and cancer, specifically aiming to: (1) review the main infectious agents associated with development of cancer and the role of microbiota in cancer susceptibility; (2) highlight the higher vulnerability of cancer patients to acquire infectious diseases; (3) document the relationship between cancer cells and tissue microbiota; (4) describe the role of intratumoral bacteria in the response and toxicity to cancer therapy.This research was funded by National Funds through FCT—Fundação para a Ciência e a Tecnologia, I.P., within CINTESIS, R&D Unit, grant number UIDB/4255/2020

The use of DRAQ5 to monitor intracellular DNA in Escherichia coli by flow cytometry

Flow cytometry provides a rapid and high-content multiparameter analysis of individual microorganisms within a population. In the past years, several fluorescent stains were developed in order to monitor DNA content distribution and cell-cycle phases, mainly in eukaryotic cells. Recently, due to its low detection limits, several of these fluorescent stains were also applied to prokaryotic cells. In this study, the ability of a novel far-red fluorescent stain DRAQ5 in assessing intracellular DNA content distribution in Escherichia coli DH5alpha was evaluated. The results showed that a DRAQ5-labelled live E. coli suspension can be obtained by incubation of 1 x 10(6) cells/mL with 5 microM DRAQ5 in PBS buffer supplemented with EDTA (pH = 7.4) during 30 min at 37 degrees C. Flow cytometric analysis of fixed E. coli cells revealed that ethanol should be used in detriment of glutaraldehyde for DRAQ5 labelling. After the analysis of RNase and DNase digested samples, DRAQ5 was proven to be a specific DNA labelling stain. The present study demonstrates that the use of DRAQ5 as a DNA-labelling stain provides an easy assessment of intracellular DNA content and cell-cycle phases in gram-negative bacteria such as E. coli.info:eu-repo/semantics/publishedVersio

In Vitro Effect of Local Anesthetics on Candida albicans Germ Tube Formation

Objective: This study was planned to clarify the in vitro effect of lidocaine and bupivacaine on germ tube formation by Candida albicans isolates from cases of clinical vaginal candidiasis

Evaluation of physiological effects induced by manuka honey upon staphylococcus aureus and escherichia coli

Several studies have explored the antimicrobial properties of manuka honey (MkH). However, the data available regarding antibacterial action mechanisms are scarcer. The aim of this study was to scrutinize and characterize primary e ects of manuka honey (MkH) upon the physiological status of Staphylococcus aureus and Escherichia coli (as Gram-positive and Gram-negative bacteria models, respectively), using flow cytometry (FC) to reveal its antibacterial action mechanisms. E ects of MkH on membrane potential, membrane integrity and metabolic activity were assessed using di erent fluorochromes in a 180 min time course assay. Time-kill experiments were carried out under the same conditions. Additionally, MkH e ect on e ux pumps was also studied in an E. coli strain with an over-expression of several e ux pumps. Exposure of bacteria to MkH resulted in physiological changes related to membrane potential and membrane integrity; these e ects displayed slight di erences among bacteria. MkH induced a remarkable metabolic disruption as primary physiological effect upon S. aureus and was able to block effux pump activity in a dose-dependent fashion in the E. coli strain.This work was supported by the Consejería de Sanidad of Junta de Castilla y León; under grant GRS 551/A/10. Patricia Combarros-Fuertes was funded by Consejería de Educación of Junta de Castilla y León and European Social Fund.info:eu-repo/semantics/publishedVersio

Antibacterial action mechanisms of honey: physiological effects of avocado, chestnut, and polyfloral honey upon Staphylococcus aureus and Escherichia coli

Numerous studies have explored the antibacterial properties of di erent types of honey from all around the world. However, the data available describing how honey acts against bacteria are few. The aim of this study was to apply a flow cytometry (FC) protocol to examine and characterize the primary e ects of three varieties of honey (avocado, chestnut and polyfloral) upon physiological status of Staphylococcus aureus and Escherichia coli cells to reveal their antibacterial action mechanisms. The e ects of honey samples on membrane potential, membrane integrity, and metabolic activity were assessed using di erent fluorochromes, in a 180 min time course assay. Time-kill experiments were also carried out under similar conditions. Exposure of S. aureus and E. coli to the distinct honey samples resulted in physiological changes related to membrane polarization and membrane integrity. Moreover, honey induced a remarkable metabolic disruption as primary physiological e ect upon S. aureus. The di erent honey samples induced quite similar e ects on both bacteria. However, the depth of bacteria response throughout the treatment varied depending on the concentration tested and among honey varieties, probably due to compositional di erences in the honey.This work was supported by the Consejería de Sanidad of Junta de Castilla y León; under Grant GRS 551/A/10. Patricia Combarros-Fuertes was funded by Consejería de Educación of Junta de Castilla y León and European Social Fund.info:eu-repo/semantics/publishedVersio

Evaluation of honey cell-induced effects on bacteria

Although there exist numerous studies to establish antimicrobial activity of different types of honey, few studies describe the mechanism of their antimicrobial action. Flow cytometry is an analytical method which allows to characterize cell populations at single cell level.info:eu-repo/semantics/publishedVersio

Development of cross-resistance by Aspergillus fumigatus to clinical azoles following exposure to prochloraz, an agricultural azole

Background: The purpose of this study was to unveil whether azole antifungals used in agriculture, similar to the clinical azoles used in humans, can evoke resistance among relevant human pathogens like Aspergillus fumigatus, an ubiquitous agent in nature. Additionally, cross-resistance with clinical azoles was investigated. Antifungal susceptibility testing of environmental and clinical isolates of A. fumigatus was performed according to the CLSI M38-A2 protocol. In vitro induction assays were conducted involving daily incubation of susceptible A. fumigatus isolates, at 35°C and 180 rpm, in fresh GYEP broth medium supplemented with Prochloraz (PCZ), a potent agricultural antifungal, for a period of 30 days. Minimal inhibitory concentrations (MIC) of PCZ and clinical azoles were monitored every ten days. In order to assess the stability of the developed MIC, the strains were afterwards sub-cultured for an additional 30 days in the absence of antifungal. Along the in vitro induction process, microscopic and macroscopic cultural observations were registered. Results: MIC of PCZ increased 256 times after the initial exposure; cross-resistance to all tested clinical azoles was observed. The new MIC value of agricultural and of clinical azoles maintained stable in the absence of the selective PCZ pressure. PCZ exposure was also associated to morphological colony changes: macroscopically the colonies became mostly white, losing the typical pigmentation; microscopic examination revealed the absence of conidiation. Conclusions: PCZ exposure induced Aspergillus fumigatus morphological changes and an evident increase of MIC value to PCZ as well as the development of cross-resistance with posaconazole, itraconazole and voriconazole.IFR and IMM are supported by FCT (Fundação Ciência e Tecnologia). IFR is supported by FCT PhD grant (SFRH/BD/91155/2012). I.MM is supported by FCT, Ciência 2008 and co-financed by the European Social Fund. The authors would like to thank Isabel Santos for the excellent technical assistance. Part of the results was presented at the 52nd Interscience Conference on Antimicrobial Agents and Chemotherapy, ICAAC, held San Francisco, USA, September 2012.info:eu-repo/semantics/publishedVersio

Antibacterial Action Mechanisms of Honey: Physiological Effects of Avocado, Chestnut, and Polyfloral Honey upon Staphylococcus aureus and Escherichia coli

[EN] Numerous studies have explored the antibacterial properties of different types of honey from all around the world. However, the data available describing how honey acts against bacteria are few. The aim of this study was to apply a flow cytometry (FC) protocol to examine and characterize the primary effects of three varieties of honey (avocado, chestnut and polyfloral) upon physiological status of Staphylococcus aureus and Escherichia coli cells to reveal their antibacterial action mechanisms. The effects of honey samples on membrane potential, membrane integrity, and metabolic activity were assessed using different fluorochromes, in a 180 min time course assay. Time-kill experiments were also carried out under similar conditions. Exposure of S. aureus and E. coli to the distinct honey samples resulted in physiological changes related to membrane polarization and membrane integrity. Moreover, honey induced a remarkable metabolic disruption as primary physiological effect upon S. aureus. The different honey samples induced quite similar effects on both bacteria. However, the depth of bacteria response throughout the treatment varied depending on the concentration tested and among honey varieties, probably due to compositional differences in the honeySIThis work was supported by the Consejería de Sanidad of Junta de Castilla y León; under Grant GRS 551/A/10. Patricia Combarros-Fuertes was funded by Consejería de Educación of Junta de Castilla y León and European Social Fun

Bacteriostatic and bactericidal activity of diferente Spanish honey

The aim of this study is to determine the antimicrobial capacity of Spanish honey from diferente floral and geographical origins in order lo select one which shows higher antimicrobial activity to be used in the prevention and trealment of oral mucositis derived from treatments of radio and/or chemotherapy.info:eu-repo/semantics/publishedVersio