Short-term antibiotic treatment has differing long-term impacts on the human throat and gut microbiome “Running title : Long-term antibiotic impacts Hedvig Jakobsson 1,2 , Cecilia Jernberg 1 , Anders F Andersson 1,3 , Maria Sjolund-Karlsson 1 , Janet K Jansson 4,5* , and Lars Engstrand 1,2 Department of Bacteriology, Swedish Institute for Infectious Disease Control, Stockholm, Sweden, 2 Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden, 3 Limnology/Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Sweden, 4 Department of Microbiology, Swedish University of Agricultural Sciences, Uppsala, Sweden, Berkeley National Laboratory, Berkeley, CA, USA. Ecology Department, Lawrence phone number: +46 (8) 4572412; fax: +46-8-301797; email: hedvig.jakobsson@smi.se ∗Corresponding author. Mailing address: Department of Bacteriology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden. Phone: +46-8-4572415. Fax: 46-8- 301797. Email: lars.engstrand@smi.se Abbreviations: T-RFLP, terminal-restriction fragment length polymorphism; TRFs, terminal- restriction fragments; OTU, operational taxonomic unit; CA, correspondence analysis; erm, erythromycin resistance methylase. *Jansson's work is partially supported by the U.S. Department of Energy and Lawrence Berkeley National Laboratory under Contract No. DE-AC02-05CH11231.

Short-term antibiotic treatment has differing long-term impacts on the human throat and gut microbiome

The natural population of the aquatic environment supports a diverse aquatic biota and a robust seafood industry. However, this environment also provides an appropriate niche for the growth of pathogenic bacteria that cause problems for human health. For example, species of the genus Vibrio inhabit marine and estuarine environments. This genus includes species that are pathogenic to aquaculture, invertebrates, and humans. In humans, they can cause prominent diseases like gastroenteritis, wound infections, and septicemia. The increased number of multidrug resistant (MDR) Vibrio strains has drawn the attention of the scientific community to develop new broad-spectrum antibiotics. Hence, in this paper we report the bactericidal effects of compounds derived from Piper betel plants: piperidine, chlorogenic acid, and eugenyl acetate, against various strains of Vibrio species. The different MIC90 values were approximately in a range of 2-6 mg/mL, 5-16 mg/mL, 5-20 mg/mL, and 30-80 mg/mL, for piperidine, chlorogenic acid, and eugenyl acetate, respectively. Piperidine showed the best anti-Vibrio effect against the five Vibrio species tested. Interestingly, combinations of sub-inhibitory concentrations of piperidine, chlorogenic acid, and eugenyl acetate showed inhibitory effects in the Vibrio strains. Furthermore, these compounds showed synergism or partial synergism effects against MDR strains of the Vibrio species when they were incubated with antibiotics (ampicillin and chloramphenicol).

https://www.mdpi.com/2076-0817/8/2/64/pdf

Piper betel Compounds Piperidine, Eugenyl Acetate, and Chlorogenic Acid Are Broad-Spectrum Anti-Vibrio Compounds that Are Also Effective on MDR Strains of the Pathogen

The spread of multidrug-resistant (MDR) Vibrio cholerae necessitates the development of novel prevention and treatment strategies. This study aims to evaluate the in vitro antibacterial activity of green tea polyphenol (−)-epigallocatechin-3-gallate (EGCG) against MDR V. cholerae. First, MIC and MBC values were evaluated by broth microdilution techniques against 45 V. cholerae strains. The checkerboard assay was then used to determine the synergistic effect of EGCG and tetracycline. The pharmaceutical mode of action of EGCG was clarified by time-killing kinetics and membrane disruption assay. Our results revealed that all of the 45 clinical isolates were susceptible to EGCG, with MIC and MBC values in the range of 62.5–250 µg/mL and 125–500 µg/mL, respectively. Furthermore, the combination of EGCG and tetracycline was greater than either treatment alone, with a fractional inhibitory concentration index (FICI) of 0.009 and 0.018 in the O1 and O139 representative serotypes, respectively. Time-killing kinetics analysis suggested that EGCG had bactericidal activity for MDR V. cholerae after exposure to at least 62.5 µg/mL EGCG within 1 h. The mode of action of EGCG might be associated with membrane disrupting permeability, as confirmed by scanning electron microscopy. This is the first indication that EGCG is a viable anti-MDR V. cholerae treatment.

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Antimicrobial Activity of the Green Tea Polyphenol (−)-Epigallocatechin-3-Gallate (EGCG) against Clinical Isolates of Multidrug-Resistant Vibrio cholerae

Metabolic and molecular modelling of zebrafish gut biome to unravel antimicrobial peptides through metagenomics.

Vibrio cholerae is the causative organism of the cholera epidemic, and it remains a serious global health problem, particularly the multidrug-resistant strain, despite the development of several generic drugs and vaccines over time. Natural products have long been exploited for the treatment of various diseases, and this study aimed to evaluate the in vitro antibacterial activity of coffee beans and coffee by-products against V. cholerae antimicrobial resistant strains. A total of 9 aqueous extracts were investigated, including light coffee (LC), medium coffee (MC), dark coffee (DC), dried green coffee (DGC), dried red coffee (DRC), fresh red coffee (FRC), Arabica leaf (AL), Robusta leaf (RL), and coffee pulp (CP). The influential coffee phytochemicals, i.e., chlorogenic acid (CGA), caffeic acid (CA), and caffeine, were determined using HPLC. The antibacterial properties were tested by agar well-diffusion techniques, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were further determined against 20 V. cholerae isolates. The results revealed that all tested strains were sensitive to coffee extracts, with MIC and MBC values in the range of 3.125–25.0 mg/mL and 12.5–50.0 mg/mL, respectively. With a MIC of 6.25 mg/mL, DGC, DRC, and CP appeared to be the most effective compounds against 65, 60, and 55% of clinical strains, respectively. The checkerboard assay revealed that the combination of coffee extract and tetracycline was greater than either treatment alone, with the fractional inhibitory concentration index (FICI) ranging from 0.005 to 0.258. It is important to note that CP had the lowest FICI (0.005) when combined with tetracycline at 60 ng/mL, which is the most effective dose against V. cholerae six-drug resistance strains (azithromycin, colistin, nalidixic acid, sulfamethoxazole, tetracycline, and trimethoprim), with a MIC of 47.5 μg/mL (MIC alone = 12.5 mg/mL). Time killing kinetics analysis suggested that CA might be the most effective treatment for drug-resistant V. cholerae as it reduced bacterial growth by 3 log10 CFU/mL at a concentration of 8 mg/mL within 1 h, via disrupting membrane permeability, as confirmed by scanning electron microscopy (SEM). This is the first report showing that coffee beans and coffee by-product extracts are an alternative for multidrug-resistant V. cholerae treatment.

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Potential Antimicrobial Properties of Coffee Beans and Coffee By-Products Against Drug-Resistant Vibrio cholerae

Background Mycobacterium tuberculosis, Vibrio cholerae, and pathogenic Escherichia coli are global concerns for public health. The emergence of multi-drug resistant (MDR) strains of these pathogens is creating additional challenges in controlling infections caused by these deadly bacteria. Recently, we reported that Acetate kinase (AcK) could be a broad-spectrum novel target in several bacteria including these pathogens. Methods Here, using in silico and in vitro approaches we show that (i) AcK is an essential protein in pathogenic bacteria; (ii) natural compounds Chlorogenic acid and Pinoresinol from Piper betel and Piperidine derivative compound 6-oxopiperidine-3-carboxylic acid inhibit the growth of pathogenic E. coli and M. tuberculosis by targeting AcK with equal or higher efficacy than the currently used antibiotics; (iii) molecular modeling and docking studies show interactions between inhibitors and AcK that correlate with the experimental results; (iv) these compounds are highly effective even on MDR strains of these pathogens; (v) further, the compounds may also target bacterial two-component system proteins that help bacteria in expressing the genes related to drug resistance and virulence; and (vi) finally, all the tested compounds are predicted to have drug-like properties. Results and conclusion Suggesting that, these Piper betel derived compounds may be further tested for developing a novel class of broad-spectrum drugs against various common and MDR pathogens.

Acetate Kinase (AcK) is Essential for Microbial Growth and Betel-derived Compounds Potentially Target AcK, PhoP and MDR Proteins in M. tuberculosis, V. cholerae and Pathogenic E. coli: An in silico and in vitro Study.

A healthy human body functions in sync with a wide array of gut microbes collectively known as human gut microbiome. They complement in a number of functions which are essential in our daily life such as in food metabolism. Various illnesses including colon cancer, autism, obesity, and autoimmune diseases have been linked to an imbalanced gut microbiota. Antibiotics are indispensable drug; however, the administration of antibiotics in humans as well as in animal farms has shown to increase antimicrobial resistance genes (ARGs) in gut microbiome. This is of serious concern since the commensals in gut microbiome could capture ARGs through horizontal gene transfer which in turn could cause postsurgical infections. In addition, numerous studies have consistently shown that the gut microbiome is unique to each individual. Hence, in-depth knowledge on the gut microbiota community and the factor responsible for shaping and spreading of ARGs is essential. This would in turn enable the development of custom-tailored personalized food and drugs in the future.

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Metagenomics of Antimicrobial Resistance in Gut Microbiome

Vector-borne diseases (VBDs) are caused majorly by arthropods which effects millions of people worldwide. Malaria alone is a dreadful disease in developing countries. However, the emergence of new VBDs and their resistance to standard drugs have posed a serious threat to the world. Hence, a new source of drugs to treat the dreadful VBDs is the need of the hour. It is surprising that one of the most ancestral innate immunities in every class of life is known as host 2defense peptides or antimicrobial peptides (AMPs) and have not been much in focus majorly due to lack of revenue generation. AMPs have shown to have promising anti-infective activates on a wide range of microbes including viral and cancer cells. In this chapter, we have compiled some of the research on microbial biomolecules targeting the vector and the pathogens along with the possible mode of action.
 The later part of the chapter focuses on prevention of VBDs through mathematical models, regulatory measures, and community-level participation. Vectors are highly dependent on the environmental condition for its maturation and life cycles. Therefore, in order to make the best usage of various environmental data, models pertaining to the VBD outbreaks or the abundance of vectors can be built using environmental data and NASA’s satellite-based Moderate Resolution Imaging Spectroradiometer in order to predict the most likely possibility of prevention using powerful algorithms. We have also discussed the importance and the problems faced in imparting knowledge through a public awareness program regarding various VBDs and the importance of community-level participation along with personal prophylaxis measures.

Ranjith Kumavath

Papers

Acetate Kinase (AcK) is Essential for Microbial Growth and Betel-derived Compounds Potentially Target AcK, PhoP and MDR Proteins in M. tuberculosis, V. cholerae and Pathogenic E. coli: An in silico and in vitro Study.

Metagenomics of Antimicrobial Resistance in Gut Microbiome

Microbial Biomolecules : Challenges to Control and Prevent Vector-Borne Diseases