Indole-containing arene-ruthenium complexes with broad spectrum activity against antibiotic-resistant bacteria.

Antimicrobial resistant (AMR) bacteria are emerging and spreading globally, threatening our ability to treat common infectious diseases. The development of new classes of antibiotics able to kill or inhibit the growth of such AMR bacteria through novel mechanisms of action is therefore urgently needed. Here, a new family of indole-containing arene ruthenium organometallic compounds are screened against several bacterial species and drug resistant strains. The most active complex [(p-cym)Ru(O-cyclohexyl-1H-indole-2-carbothioate)Cl] (3) shows growth inhibition and bactericidal activity against different organisms (Acinetobacter baumannii, Mycobacterium abscessus, Mycobacterium tuberculosis, Staphylococcus aureus, Salmonella enterica serovar Typhi and Escherichia coli), demonstrating broad-spectrum inhibitory activity. Importantly, this compound series exhibits low toxicity against human cells. Owing to the novelty of the antibiotic family, their moderate cytotoxicity, and their inhibitory activity against Gram positive, Gram negative and acid-fast, antibiotic resistant microorganisms, this series shows significant promise for further development.

3-D printed polyvinyl alcohol matrix for detection of airborne pathogens in respiratory bacterial infections.

Novel sampling matrices were manufactured using 3D printing for the detection of respiratory pathogens in expired air. A specific configuration of the matrices was designed using Computer-Aided Design software. Polyvinyl alcohol (PVA) was printed using fused deposition modelling to create a multilayer matrix to enhance the capture of bacteria. The performance of these matrices was compared with gelatine filters that have been used for this work to date. PVA matrices (60 mm diameter) were contaminated with bacteria either by direct inoculation, or by aerosol exposure using an Omron A3 nebuliser. Rough and smooth morphotypes of Mycobacterium abscessus, M. smegmatis and M. bovis BCG, were used in this study to contaminate the matrices. PVA matrices and gelatine sampling filters were contaminated to compare recovery rates for quantitative analyses. These were dissolved in water, bacteria pelleted and DNA extracted followed by a Mycobacterium-specific quantitative Polymerase Chain Reaction (qPCR).The results showed that 3D printed PVA matrices are very effective to capture the bacteria. 3D printed PVA matrix and gelatine filters yielded results of the same order of magnitude for mycobacterial analyses, however, PVA matrix offers several advantages over the latter material. 3D printed PVA is considered as an economic and time-effective matrix as it is cheaper than gelatine filters. PVA is sufficiently robust to be handled and loaded into the surgical masks for sampling, compared to the brittle gelatine filters that required supportive frames. PVA is a synthetic material and it is suitable for DNA-based analyses, whilst gelatine is derived from animal collagen, and carries a high bacterial DNA background that interferes with the target DNA analysis. Furthermore, PVA dissolves in distilled water without requiring chemicals or enzymes, such as the case for gelatine hydrolysis. To summarise, 3D printed PVA sampling matrix is considered a promising tool used for microbiological diagnostic purposes.

Protein kinase B controls Mycobacterium tuberculosis growth via phosphorylation of the transcriptional regulator Lsr2 at threonine 112.

Mycobacterium tuberculosis (Mtb) is able to persist in the body through months of multi-drug therapy. Mycobacteria possess a wide range of regulatory proteins, including the protein kinase B (PknB) which controls peptidoglycan biosynthesis during growth. Here, we observed that depletion of PknB resulted in specific transcriptional changes that are likely caused by reduced phosphorylation of the H-NS-like regulator Lsr2 at threonine 112. The activity of PknB towards this phosphosite was confirmed with purified proteins, and this site was required for adaptation of Mtb to hypoxic conditions, and growth on solid media. Like H-NS, Lsr2 binds DNA in sequence-dependent and non-specific modes. PknB phosphorylation of Lsr2 reduced DNA binding, measured by fluorescence anisotropy and electrophoretic mobility shift assays, and our NMR structure of phosphomimetic T112D Lsr2 suggests that this may be due to increased dynamics of the DNA-binding domain. Conversely, the phosphoablative T112A Lsr2 had increased binding to certain DNA sites in ChIP-sequencing, and Mtb containing this variant showed transcriptional changes that correspond with the change in DNA binding. In summary, PknB controls Mtb growth and adaptations to the changing host environment by phosphorylating the global transcriptional regulator Lsr2.

[The genetic description of Acinetobacter baumannii and Pseudomonas aeruginosa strains isolated from patients with hospital acquired pneumonia hospitalized in intensive care unit]. / Genetyczna charakterystyka szczepów Acinetobacter baumannii oraz Pseudomonas aeruginosa izolowanych od chorych z zapaleniem pluc hospitalizowanych w oddziale intensywnej terapii.

The aim of study was to recognize the epidemiology of hospital acquired pneumonia on the base of genotypes of Acinetobacter baumannii and Pseudomonas aeruginosa strains. Gram negative-non fermenting bacilli are the most frequent aetiologic agent of hospital acquired pneumonia among patients from Anesthesiology and Intensive Care Unit in the Rydygiers hospital in Cracow. In the following research RAPD-PCR method was applied and there 272, 208, ERIC- 2 and PAL- 2 primers were used. The investigation was conducted among 33 Acinetobacter baumannii and 31 Pseudomonas aeruginosa strains which were isolated from endotracheal aspirates (ETA). ETA were taken from 19 patients with microbiologically confirmed pneumonia. The result of our study shows that most A. baumannii strains came from hospital habitat. In the investigated group of A. baumannii strains, 31 belonged to 3 clonal groups and probably came from two bacteria subpopulations which were present in ICU from a long time. There were only two isolates which had got the posthospital origin. Moreover, the assay of genetic similarity between A. baumannii strains, isolated from individual patients, showed that only in two patients were observed strains with different genetic profiles. Isolates which came from 8 patients had got the same pattern of bands. There were many genetic differences between investigated P. aeruginosa strains. In the group of 31 isolates, which were investigated by using 208, 272, ERIC- 2 and PAL- 2 primers, recognized respectively 10, 10, 13 and 8 of genetic profiles. All isolates of P. aeruginosa probably came from a few subpopulations of hospital strain which has undergone evolutionary divergence phenomenon in time as a result of changing condition of hospital environment and application of antibiotics. The assay of genotype of P. aeruginosa strains which were repeatedly isolated from individual patients showed that only from two patients strains with 100% genetic homology were isolated.