Paula Aline Zanetti Campanerut-Sá

Cinnamaldehyde induces changes in the protein profile of Salmonella Typhimurium biofilm

The effect of cinnamaldehyde against biofilm cells of Salmonella Typhimurium ATCC 14028 was evaluated. We also assessed differential protein patterns that were expressed by biofilms compared with planktonic cells and protein expression by cinnamaldehyde-treated biofilms cells. This compound decreased biofilm biomass and metabolic activity of biofilms at both concentrations tested. Cinnamaldehyde treatment reduced the number of attached cells in polypropylene, reflected by colony count and scanning electron microscopy. The proteomic analysis of biofilms compared with planktonic cells indicated that several proteins were upregulated or downregulated, especially proteins that are involved in energy metabolism. Peroxiredoxin, ATP synthase alpha chain protein, conjugal transfer nickase/helicase TraI and elongation factor G were upregulated in untreated-biofilm cells, and their expression decreased as a function of cinnamaldehyde treatment. Cinnamaldehyde had antibiofilm activity, and several differentially expressed proteins identified provide potential and interesting targets to explore new control strategies for S. Typhimurium biofilms.

Mutations in catalase-peroxidase KatG from isoniazid resistant Mycobacterium tuberculosis clinical isolates: insights from molecular dynamics simulations

The current multidrug therapy for tuberculosis (TB) is based on the use of isoniazid (INH) in combination with other antibiotics such as rifampin, ethambutol and pyrazinamide. Literature reports have shown that Mycobacterium tuberculosis, the causative agent of TB, has become resistant to this treatment by means of point mutations in the target enzymes of these drugs, such as catalase-peroxidase (KatG). By means of equilibrium molecular dynamics in the presence of the ligand, this work evaluated ten point mutations described in the enzyme KatG that are related to resistance to INH . The results showed that the resistance mechanism is related to stereochemical modifications at the N-terminal domain of the protein, which restrict INH access to its catalytic site, not involving mechanisms of electrostatic nature. These results show insights that can be useful for the identification of new anti-TB drugs which may be able to circumvent this mechanism of resistance.

Photodynamic inactivation of foodborne bacteria by eosin Y

The aim of this study was evaluate the effect of photodynamic inactivation mediated by eosin Y in Salmonella enterica serotype Typhimurium ATCC 14028, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Bacillus cereus ATCC 11778.

Systematic review on the proteomic profile of Mycobacterium tuberculosis exposed to drugs.

The authors present an overview about proteomics studies in Mycobacterium tuberculosis exposed to some anti‐tuberculosis drugs and new candidates, using two‐dimensional gel electrophoresis and mass spectrometry. To date, that the authors have knowledge, this is the first studies that was performed specifically in M. tuberculosis using systematic review on electronic literature conducted in three databases using the following search terms: tuberculosis OR mycobacterium tuberculosis, proteome OR proteomics, and mass spectrometry electrospray ionization OR matrix‐assisted laser desorption ionization OR two‐dimensional gel electrophoresis. By electronic search, 622 abstracts of the original articles published from November 2003 to March 2016 were selected. After the selection, four articles fulfill proposed criteria and were included in this study. The studies reported changes in the protein profile of M. tuberculosis after exposure to isoniazid, ethambutol, streptomycin, ofloxacin, moxifloxacin and two new drugs candidates, SQ109 and ATB107. In conclusion, the proteins changes were related to the synthesis of mycolic acids, cellular metabolism pathways, bacterial stress and starvation.

RD Rio Mycobacterium tuberculosis lineage in the Brazil/Paraguay/Argentina triple border

The high tuberculosis (TB) incidence rates, the closeness of the cities and the high migration flux on the Brazil/Paraguay/Argentina border deserves an in-depth study, using Mycobacterial Interspersed Repetitive Unit (MIRU) and Spoligotyping genetic markers to explore the impact of the Mycobacterium tuberculosis RDRio lineage on disease transmission and resistance to anti-TB drugs in this setting. Although without the totality of M. tuberculosis isolates causing TB in this studied setting, a number of 97 isolates obtained from sputa samples culture of patients with confirmed TB, from 2013 to 2015, were submitted to 24 loci MIRU, Spoligotyping, detection of RDRio lineage and detection of mutation related to isoniazid and rifampicin resistance by MTBDRplus/DNA STRIP. In this sample, it was observed high clonal variability of circulating M. tuberculosis isolates causing TB in Brazilian cities bordering Paraguay and Argentina. The percentage of RDRio lineage causing TB in this setting was 15.46%, and lower than the detected in different areas of Brazil. According to 24 loci MIRU, the major MIRU International Type (MIT) related with RDRio lineage were MIT 26, MIT 738, MIT 601 with four, two and one isolates, respectively. Eight isolates with RDRio marker were classified as orphans. The mainly Spoligofamily related with RDRio lineage was LAM1 and LAM9 and no relationship between RDRio lineage and resistance in M. tuberculosis isolates circulating in this setting could be established. This work is pioneer in studying the dynamics of RDRio lineage transmission on the Brazil/Paraguay/Argentina border and deserves further studies to analyze the real contribution of the RDRio lineage in outbreaks and the risk of significant development of MDR-TB in the setting studied.

Combinatory activity of linezolid and levofloxacin with antituberculosis drugs in Mycobacterium tuberculosis

SETTING The increase of multidrug and extensively drug resistant Mycobacterium tuberculosis strains turns the search for new tuberculosis (TB) treatment options of paramount importance. OBJECTIVE In this sense, the present study evaluates the in vitro activity of isoniazid (INH)/rifampicin (RIF)/levofloxacin (LVX) and INH/RIF/linezolid (LNZ) combinations in resistant M. tuberculosis. DESIGN The activities of the combinations were evaluated with M. tuberculosis H37Rv, susceptible and 10 resistant clinical isolates by three-dimensional checkerboard. LVX and LNZ were used as the third drug at fixed ½ and ¼ minimum inhibitory concentration (MIC). INH and RIF were tested at concentrations ranging from 0.0009 μg/mL to 50 μg/mL and 0.0009 μg/mL to 800 μg/mL, respectively. The combinatorial effects were determined by the Fractional Inhibitory Concentration Index (FICI). FICI values ≤ 0.75, 0.75-4 and ≥4 were considered as synergism, indifferent and antagonism, respectively. RESULTS MIC ranged from 0.03 - 6.25 μg/mL for INH, 0.008-100 μg/mL for RIF, 0.12-0.25 μg/mL for LVX and 0.25-0.5 μg/mL for LNZ in the H37Rv and all clinical isolates. INH/RIF/LVX and INH/RIF/LNZ synergisms were observed in 40 and 50% of the resistant M. tuberculosis clinical isolates and better observed for INH and RIF combined to LVX or LNZ at ¼ MIC. CONCLUSION The present study calls attention for the potential use of INH/RIF/LVX and INH/RIF/LNZ combinations in the treatment of resistant TB.

New insights on Ethambutol targets in Mycobacterium tuberculosis

BACKGROUND In recent years, very few effective drugs against Mycobacterium tuberculosis have emerged, which motivates the research with drugs already used in the treatment of tuberculosis. Ethambutol is a bacteriostatic drug that affects cell wall integrity, but the effects of this drug on bacilli are not fully exploited. OBJECTIVE Based on the need to better investigate the complex mechanism of action of ethambutol, our study presented the proteome profile of M. tuberculosis after different times of ethambutol exposure, aiming to comprehend the dynamics of bacilli response to its effects. M. tuberculosis was exposed to ½ MIC of ethambutol at 24 and 48 hours. The proteins were identified by MALDI-TOF/TOF. RESULTS The main protein changes occurred in metabolic proteins as dihydrolipoyl dehydrogenase (Rv0462), glutamine synthetase1 (Rv2220), electron transfer flavoprotein subunit beta (Rv3029c) and adenosylhomocysteinase (Rv3248c). CONCLUSION Considering the functions of these proteins, our results support that the intermediary metabolism and respiration were affected by ethambutol and this disturbance provided proteins that could be explored as additional targets for this drug.