A5032507837- Antibiotic Resistance in Bacteria
- Bacterial Genetics and Biotechnology
- Antibiotics Pharmacokinetics and Efficacy
- Bacterial Identification and Susceptibility Testing
- Pneumocystis jirovecii pneumonia detection and treatment
- Antimicrobial Peptides and Activities
- Antimicrobial Resistance in Staphylococcus
- Salmonella and Campylobacter epidemiology
- Probiotics and Fermented Foods
- Lipid Membrane Structure and Behavior
- Tuberculosis Research and Epidemiology
- Immune Response and Inflammation
- Clostridium difficile and Clostridium perfringens research
- Escherichia coli research studies
- Streptococcal Infections and Treatments
- Bacteriophages and microbial interactions
- Viral gastroenteritis research and epidemiology
- Pneumonia and Respiratory Infections
- Antibiotic Use and Resistance
- Vibrio bacteria research studies
- Mycobacterium research and diagnosis
- Yersinia bacterium, plague, ectoparasites research
- Infective Endocarditis Diagnosis and Management
- RNA and protein synthesis mechanisms
- Gut microbiota and health
University of Helsinki
2011-2020
Finnish Institute for Health and Welfare
2001-2018
Helsinki University Hospital
2008-2018
Technopolis (Finland)
2017
Hospital District of Helsinki and Uusimaa
2007-2016
Czech Academy of Sciences, Institute of Microbiology
2010
Valio (Finland)
2002
Medical Diagnostic Laboratories (United States)
2000
Institute for Molecular Medicine Finland
1983-1999
Public Health Institute
1983-1999
Flavonoids are effective antioxidants and, in theory, may provide protection against cancer, although direct human evidence of this is scarce. The relation between the intake antioxidant flavonoids and subsequent risk cancer was studied among 9,959 Finnish men women aged 15–99 years initially free. Food consumption estimated by dietary history method, covering total habitual diet during previous year. During a follow-up 1967–1991, 997 cases 151 lung were diagnosed. An inverse association...
The outer membrane of gram-negative bacteria provides the cell with an effective permeability barrier against external noxious agents, including antibiotics, but is itself a target for antibacterial agents such as polycations and chelators. Both groups weaken molecular interactions lipopolysaccharide constituent membrane. Various are able, at least under certain conditions, to bind anionic sites lipopolysaccharide. Many these disorganize cross render it permeable drugs which permeate intact...
Lactobacilli supposedly have low pathogenicity; they are seldom detected in blood culture. Lactobacillus rhamnosus GG, which originates indigenously the human intestine, became available for use as a probiotic 1990 Finland. We evaluated possible effects of increased L. GG on occurrence bacteremia due to lactobacilli. were isolated 0.02% all cultures and 0.2% with positive results Helsinki University Central Hospital Finland whole, no trends seen that suggested an increase bacteremia. The...
The outer membrane-disorganizing effect of a short (10-min) treatment with polycationic agents was studied smooth Salmonella typhimurium used as test organism. were the protamine salmine, lysine polymer 20 residues (lysine20), and deacylated polymyxin B derivative nonapeptide. Two different types found. Protamine lysine20 released to 30% lipopolysaccharide from membrane sensitized bacteria anionic detergent sodium dodecyl sulfate but did not (under these conditions) make permeable...
Polymyxin B nonapeptide, a polymyxin derivative which lacks the fatty acyl part and bactericidal activity of polymyxin, was shown to sensitize smooth encapsulated Escherichia coli (O18:K1) Salmonella typhimurium hydrophobic antibiotics (novobiocin, fusidic acid, erythromycin, clindamycin, nafcillin, cloxacillin). The nonapeptide-treated bacteria were as sensitive these are deep rough mutants. A lysine polymer with 20 residues (lysine 20) had largely similar effect. Larger polymers protamine...
A synthetic peptide, KFFKFFKFFK [corrected], consisting of cationic lysine residues and hydrophobic phenylalanine was found to sensitize gram-negative bacteria amphipathic antibiotics. At a concentration 3 micrograms/ml, it decreased the MIC rifampin for smooth, encapsulated Escherichia coli by factor 300. Other susceptible bacterial species included Enterobacter cloacae, Klebsiella pneumoniae, Salmonella typhimurium, but Pseudomonas aeruginosa resistant. Similar results were obtained with...
Summary Lipopolysaccharides (LPS) of two polymyxin‐resistant (pmr) mutants and the corresponding parent strain Escherichia Coli were chemically analysed for composition subjected to 31 P‐NMR (nuclear magnetic resonance) assessment phosphate substitution. Whereas saccharide portions, fatty acids, contents similar in wild‐type pmr LPS, latter contained two‐ threefold higher amounts 2‐aminoethanol. The LPS also 4‐amino‐4‐deoxy‐ l ‐arabinopyranose ( ‐Ara p 4N), which is normally not a component...
Novel approaches for the treatment of multidrug-resistant Gram-negative bacterial infections are urgently required. One approach is to potentiate efficacy existing antibiotics whose spectrum activity limited by permeability barrier presented outer membrane. Cationic peptides derived from polymyxin B have been used permeabilize membrane, granting that would otherwise be excluded access their targets. We assessed in vitro efficacies combinations SPR741 with conventional against Escherichia...
ObjectivesCarbapenemase-producing Enterobacteriaceae (CPE) are becoming a global problem; they often resistant to nearly all available antibiotics. Here we report details on Finnish CPE isolates found until the end of 2011: carbapenemase genes, travel history and multilocus sequence typing (MLST) data.
The discovery of polymyxins, highly basic lipodecapeptides, was published independently by three laboratories in 1947. Their clinical use, however, abandoned the sixties because nephrotoxicity and better-tolerated drugs belonging to other antibiotic classes were discovered. Now polymyxins have resurged as last-resort against extremely multi-resistant strains, even though their forces clinicians administer them at doses that are lower than those required for optimal efficacy. As therapeutic...
Summary De‐ O ‐acylated lipopolysaccharides (LPS) of three polymyxin‐resistant Salmonella typhimurium pmrA mutants and their parent strains were analysed by 31 P‐NMR (nuclear magnetic resonance) in order to assess, relation polymyxin resistance, the types degree substitution phosphates LPS lipid A. mutant phosphate diesters predominated over monoesters, whereas latter more abundant wild‐type LPS. The increase proportion was traced both core oligosaccharide lipld A part. In latter,...
Mutations which severely affect the function of outer membrane Escherichia coli and Salmonella typhimurium (lpxA firA mutations lipid A synthesis rfaE mutation lipopolysaccharide inner-core synthesis) were found to decrease MICs erythromycin, roxithromycin, clarithromycin, azithromycin by factors 32 512, 1,024, 64 16 64, respectively. The sensitization for three other hydrophobic antibiotics (rifampin, fusidic acid, mupirocin) ranged from 300. permeability-increasing agents polymyxin B...
ABSTRACT The lack of novel antibiotics against gram-negative bacteria has reinstated polymyxins as the drugs last resort to treat serious infections caused by extremely multiresistant organisms. However, are nephrotoxic, and this feature may complicate therapy or even require its discontinuation. Like that aminoglycosides, nephrotoxicity might be related highly cationic nature molecule. Colistin polymyxin B carry five positive charges. Here we show derivatives carrying only three charges...
Polymyxins are cationic lipopeptides (five charges) and the last resort for treatment of serious Gram-negative infections caused by multiresistant strains. NAB741 has a cyclic peptide portion identical to that polymyxin B but carries in linear threonyl-D-serinyl residue (no instead diaminobutyryl-threonyl-diaminobutyryl (two charges). At N terminus peptide, an acetyl group mixture methyl octanoyl heptanoyl residues. sensitized Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae,...
In contrast to their polymyxin-susceptible parent strains, polymyxin-resistant Salmonella typhimurium mutants ( pmrA strains) did not lose outer membrane permeability barrier macromolecules such as lysozyme and periplasmic proteins upon polymyxin treatment. The sensitization of strains deoxycholate-induced lysis required 10-times-higher concentrations than the strains. These findings indicate that mutation affects decreases its susceptibility polymyxin. By contrast, differ from parents in...