Combination of isothiocyanates and antibiotics increases susceptibility against Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Serratia marcescens.

BACKGROUND: The development and spread of multidrug-resistant organisms (MDRO) is evolving rapidly worldwide. Although effective antibiotics are still available, some infections are difficult to treat. Among MDROs, S. marcescens and A. baumannii are among the difficult-to-treat pathogens causing for instance sepsis and urinary tract infections (UTI). Isothiocyanates (ITC) are natural plant products. The antimicrobial properties of ITC appear to be more effective in combination with some antibiotics. PURPOSE: We investigated a mixture of ITC from nature-identical plant extracts of nasturtium and horseradish in different combined concentrations with broad-spectrum antibiotics against S. marcescens, A. baumannii, E. coli, K. pneumoniae and P. mirabilis. METHODS: First, we investigated the antibacterial activity of the compounds by standard agar disc diffusion test. Next, we evaluated the minimum inhibitory concentrations (MIC) via broth dilution tests. Checkerboard technique was used to assess antimicrobial effects against sulfamethoxazole-trimethoprim, ampicillin-sulbactam, nitrofurantoin, Fosfomycin, ciprofloxacin and imipenem combined with various concentrations of ITC. RESULTS: S. marcescens strains 1-3 showed reversal of resistance at >0.075 µg/mL ITC in combination with nitrofurantoin, whereas 0.05 µg/mL ITC increased antimicrobial susceptibility. Combination of fosfomycin with 0.003 µg/mL ITC resulted in increased efficacy against resistant S. marcescens strains, E. coli, K. pneumoniae and P. mirabilis. Remarkable additive antimicrobial activity was observed at 0.03 µg/mL and 0.06 µg/mL ITC in combination with 0.125 µg/mL imipenem (FIC > 0.5). CONCLUSION: The combination of ITC and antibiotics is a promising approach for the treatment of UTI caused by MDRO. The ITC combination with selected antibiotics had synergistic and additive effects.

Antimicrobial effects of mustard oil-containing plants against oral pathogens: an in vitro study.

BACKGROUND: The present study examines the antimicrobial activity of nasturtium herb (Tropaeoli maji herba) and horseradish root (Armoraciae rusticanae radix) against clinically important oral bacterial pathogens involved in periodontitis, gingivitis, pulpitis, implantitis and other infectious diseases. METHODS: A total of 15 oral pathogens, including members of the genera Campylobacter, Fusobacterium, Prevotella, Parvimonas, Porphyromonas, Tanerella, Veillonella, and HACEK organisms, were exposed to [1] a combination of herbal nasturtium and horseradish using a standardized gas test and [2] a mixture of synthetic Isothiocyantes (ITCs) using an agardilution test. Headspace gas chromatography mass spectrometry was employed to quantify the amount of allyl-, benzyl-, and 2- phenyl- ethyl-ITC. RESULTS: With exception of Veillonella parvula, all tested species were highly susceptible to herbal nasturtium and horseradish in the gas test with minimal inhibitory concentrations (MICs) between 50/20 mg and 200/80 mg and to synthetic ITCs in the agardilution with MICs between 0.0025 and 0.08 mg ITC/mL, respectively. Minimal bactericidal concentrations extended from 0.005 mg ITC/mL to 0.34 mg ITC/mL. CONCLUSIONS: ITCs may be considered an interesting alternative to antibiotics for prevention and treatment of oropharyngeal infections, periodontitis and related diseases. Furthermore, the suitability of ITCs for endocarditis prophylaxis in dental procedures might be worth further investigation.

Hop Extract Acts as an Antioxidant with Antimicrobial Effects against Propionibacterium Acnes and Staphylococcus Aureus.

Acne is associated with hyperkeratosis, elevated levels of skin sebum and growth of Propionibacterium acnes (P. acnes) and Staphylococcus aureus (S. aureus). Furthermore, P. acnes promotes inflammation by inducing IL-6 production and oxidative stress. The aim of this study was to assess the antioxidant, anti-inflammatory and antibacterial potential of a hop-CO2-extract with 50% humulone and lupulone. The susceptibility of P. acnes and S. aureus to the hop extract was tested by using the broth microdilution technique. The minimal inhibitory concentrations (MIC) for P. acnes and S. aureus were 3.1 and 9.4 µg/mL, respectively. In addition, the hop extract showed an antioxidative effect with a half maximal inhibitory concentration (IC50) of 29.43 µg/mL as well as additional anti-inflammatory effects by reducing the IL-6 expression (IC50: 0.8 µg/mL). In addition, a gel formulation with 0.3% hop extract (w/w) had antibacterial activity against P. acnes and S. aureus (inhibition zone value: 5.5 mm and 3 mm, respectively) which was significantly superior to the placebo gel. The positive control (a gel with the antibiotic clindamycin) showed an inhibition zone of 9 mm. Due to its antioxidant, anti-inflammatory and antibacterial effects hop extract might be a treatment option for acne-prone skin.

Treating urinary tract infections due to MDR E. coli with Isothiocyanates - a phytotherapeutic alternative to antibiotics?

BACKGROUND: Multidrug-resistant (MDR) bacteria are increasingly causing urinary tract infections (UTI), which has been linked to frequent use of antibiotics. Alternative treatment regimens are urgently needed and natural isothiocyanates (ITC) may represent one. ITCs are natural plant products found in nasturtium (Tropaeoli majoris herba) and horseradish (Armoraciae rusticanae radix). PURPOSE: The objectives were to (1) assess the antimicrobial effects of nature-identical ITCs for UTI treatment caused by uropathogenic E. coli (UPEC), (2) to evaluate a potential influence of antimicrobial resistance on ITC susceptibility, and (3) to test whether ITCs affect UPEC penetration into human uroepithelial cells. METHODS: We tested 217 clinical UPEC isolates, 54.5% of which were classified as MDR, for susceptibility against ITCs. ITC susceptibility testing was performed by broth dilution using a mixture of three synthetic ITCs. Internalization was tested using human T-24 bladder carcinoma cells in an internalization assay co-incubated with UPEC (n = 5) and ITCs. RESULTS: The mean minimal inhibitory concentration (MIC) 90 was 0.17 mg/ml, showing very high susceptibility against ITCs. Interestingly, MDR E. coli were significantly less susceptible than non-MDR strains (p = .01). Internalization of UPEC was decreased by 31.9% in the mean when treated with ITCs. Overall, ITCs exerted a strong antimicrobial activity against clinical UPEC isolates and reduced internalization into uroepithelial cells. CONCLUSION: ITCs might present a promising treatment alternative for UTIs, expressing both high antimicrobial activity as well as blocking the pathogenic process of human cell penetration by UPEC. Clinical studies, however, are needed to confirm activity of ITCs in UTIs in vivo.

A Stenotrophomonas maltophilia multilocus sequence typing scheme for inferring population structure.

Stenotrophomonas maltophilia is an opportunistic, highly resistant, and ubiquitous pathogen. Strains have been assigned to genogroups using amplified fragment length polymorphism. Hence, isolates of environmental and clinical origin predominate in different groups. A multilocus sequence typing (MLST) scheme was developed using a highly diverse selection of 70 strains of various ecological origins from seven countries on all continents including strains of the 10 previously defined genogroups. Sequence data were assigned to 54 sequence types (ST) based on seven loci. Indices of association for all isolates and clinical isolates of 2.498 and 2.562 indicated a significant linkage disequilibrium, as well as high congruence of tree topologies from different loci. Potential recombination events were detected in one-sixth of all ST. Calculation of the mean divergence between and within predicted clusters confirmed previously defined groups and revealed five additional groups. Consideration of the different ecological origins showed that 18 out of 31 respiratory tract isolates, including 12 out of 19 isolates from cystic fibrosis (CF) patients, belonged to genogroup 6. In contrast, 16 invasive strains isolated from blood cultures were distributed among nine different genogroups. Three genogroups contained isolates of strictly environmental origin that also featured high sequence distances to other genogroups, including the S. maltophilia type strain. On the basis of this MLST scheme, isolates can be assigned to the genogroups of this species in order to further scrutinize the population structure of this species and to unravel the uneven distribution of environmental and clinical isolates obtained from infected, colonized, or CF patients.

Plasmid-mediated quinolone resistance in isolates obtained in german intensive care units.

Screening of 703 isolates of Enterobacteriaceae, obtained from 34 German intensive care units (ICUs), revealed qnr-positive, integron-containing isolates of Enterobacter sp. and Citrobacter freundii from four patients in 2 German ICUs. This is one of the first reports of qnr-positive strains obtained from patients in Europe.

Lack of the small plastid-encoded PsbJ polypeptide results in a defective water-splitting apparatus of photosystem II, reduced photosystem I levels, and hypersensitivity to light.

Photosystem II is a large pigment-protein complex catalyzing water oxidation and initiating electron transfer processes across the thylakoid membrane. In addition to large protein subunits, many of which bind redox cofactors, photosystem II particles contain a number of low molecular weight polypeptides whose function is only poorly defined. Here we have investigated the function of one of the smallest polypeptides in photosystem II, PsbJ. Using a reverse genetics approach, we have inactivated the psbJ gene in the tobacco chloroplast genome. We show that, although the PsbJ polypeptide is not principally required for functional photosynthetic electron transport, plants lacking PsbJ are unable to grow photoautotrophically. We provide evidence that this is due to the accumulation of incompletely assembled water-splitting complexes, which in turn causes drastically reduced photosynthetic performance and extreme hypersensitivity to light. Our results suggest a role of PsbJ for the stable assembly of the water-splitting complex of photosystem II and, in addition, support a control of photosystem I accumulation through photosystem II activity.