Attenuation of adhesion, quorum sensing and biofilm mediated virulence of carbapenem resistant Escherichia coli by selected natural plant products

Carbon-Based Nanomaterials Alter the Behavior and Gene Expression Patterns of Bacteria

One of the most dangerous characteristics of bacteria is their propensity to form biofilms and their resistance to the drugs used in clinical practice today. The total number of genes that can be categorized as virulence genes ranges from a few hundred to more than a thousand. The bacteria employ a variety of mechanisms to regulate the expression of these genes in a coordinated manner during infection. The search for new agents with anti-virulence capacity is therefore crucial. Nanotechnology provides safe platforms for targeted therapies to combat a broad spectrum of microbial infections. As a new class of innovative materials, carbon-based nanomaterials (CBNs), which include carbon dots, carbon nanotubes, graphene, and fullerenes can have strong antibacterial activity. Exposure to CBNs has been shown to affect bacterial gene expression patterns. This study investigated the effect of CBNs on the repression of specific genes related to bacterial virulence/pathogenicity.

Computational and experimental strategies for combating MBL P. aeruginosa (MBLPA) biofilms using phytochemicals: Targeting the quorum sensing network

Pseudomonas aeruginosa is a Gram-negative opportunistic bacterium, ubiquitously found in nature and causative agent in many infections. Due to increased antibiotic resistance, there is a need to develop more robust antibacterial agents from natural sources. In this study, we worked on two metallo-β-lactamase (MBL) producing Pseudomonas aeruginosa strains and targeted the Quorum Sensing mechanism (QS) of these bacteria to combat antibiotic resistance. Our study aimed at using phytochemicals which have been used since centuries in herbal medicine. We used fifteen commercially available phytochemicals and check their effects on biofilm formation, quorum sensing and inter-related mechanisms. Sub-inhibitory concentration of isoliquiritin inhibited biofilm formation 55 % in P8 at day 6 and 48 % in P6 at day 6; quorum sensing 83 % in P6 and 61 % in P8 whereas sub-inhibitory concentration of 6-gingerol suppressed biofilm formation by 48 % in P8 at day 6 and 44 % in P6 at day 6; quorum sensing 69 % in P6 and 48 % in P8, respectively. The results indicated isoliquiritin, epigallocatechin gallate, eugenol, luteolin and chrysin to be the potential candidates in inhibiting QS and related mechanisms. Isoliquiritin which was never been used before against biofilm and QS related studies, showed remarkable results and found to be more efficient in inhibiting QS than 6-gingerol -a known QS inhibitor. For examining the molecular interaction between phytochemicals and QS, In-silico molecular docking was performed between phytoligands and four QS proteins (Las I, Las R, RhlI and Rhl R). In-silico docking analysis revealed that isoliquiritin showed strong bond with amino acids (Trp34, Asp35, Asp35, Tyr105, Arg104, Val138, Thr140) present at the active site of RhlI with binding energy value of -8.4 kcal/mol as compared to that of 6-gingerol with Rhl1 (-7.3 kcal/mol). In conclusion, our study may help in controlling nosocomial infections caused by carbapenem-resistant metallo beta-lactamase P. aeruginosa (MBL-PA) by utilizing these phytochemicals in biofilms disruption and quorum sensing inhibition. Moreover their synergism with antibiotics may help in lowering the MIC of carbapenem antibiotics against such Multi-drug resistant strains.

Cupferron impairs the growth and virulence of Escherichia coli clinical isolates

AIMS

Multidrug resistance is a worrying problem worldwide. The lack of readily available drugs to counter nosocomial infections requires the need for new interventional strategies. Drug repurposing represents a valid alternative to using commercial molecules as antimicrobial agents in a short time and with low costs. Contextually, the present study focused on the antibacterial potential of the ammonium salt N-nitroso-N-phenylhydroxylamine (Cupferron), evaluating the ability to inhibit microbial growth and influence the main virulence factors.

METHODS AND RESULTS

Cupferron cytotoxicity was checked via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and hemolysis assays. The antimicrobial activity was assessed through the Kirby-Bauer disk diffusion test, broth microdilution method, and time-killing kinetics. Furthermore, the impact on different stages of the biofilm life cycle, catalase, swimming, and swarming motility was estimated via MTT and crystal violet (CV) assay, H2O2 sensitivity, and motility tests, respectively. Cupferron exhibited <15% cytotoxicity at 200 µg/mL concentration. The 90% bacterial growth inhibitory concentrations (MIC90) values recorded after 24 hours of exposure were 200 and 100 µg/mL for multidrug-resistant (MDR) and sensitive strains, respectively, exerting a bacteriostatic action. Cupferron-treated bacteria showed increased susceptibility to biofilm production, oxidative stress, and impaired bacterial motility in a dose-dependent manner.

CONCLUSIONS

In the new antimicrobial compounds active research scenario, the results indicated that Cupferron could be an interesting candidate for tackling Escherichia coli infections.

Detection of Antibiotic Resistance in Feline-Origin ESBL Escherichia coli from Different Areas of China and the Resistance Elimination of Garlic Oil to Cefquinome on ESBL E. coli

The development of drug-resistance in the opportunistic pathogen Escherichia coli has become a global public health concern. Due to the share of similar flora between pets and their owners, the detection of pet-origin antibiotic-resistant E. coli is necessary. This study aimed to detect the prevalence of feline-origin ESBL E. coli in China and to explore the resistance elimination effect of garlic oil to cefquinome on ESBL E. coli. Cat fecal samples were collected from animal hospitals. The E. coli isolates were separated and purified by indicator media and polymerase chain reaction (PCR). ESBL genes were detected by PCR and Sanger sequencing. The MICs were determined. The synergistic effect of garlic oil and cefquinome against ESBL E. coli was investigated by checkerboard assays, time-kill and growth curves, drug-resistance curves, PI and NPN staining, and a scanning electronic microscope. A total of 80 E. coli strains were isolated from 101 fecal samples. The rate of ESBL E. coli was 52.5% (42/80). The prevailing ESBL genotypes in China were CTX-M-1, CTX-M-14, and TEM-116. In ESBL E. coli, garlic oil increased the susceptibility to cefquinome with FICIs from 0.2 to 0.7 and enhanced the killing effect of cefquinome with membrane destruction. Resistance to cefquinome decreased with treatment of garlic oil after 15 generations. Our study indicates that ESBL E. coli has been detected in cats kept as pets. The sensitivity of ESBL E. coli to cefquinome was enhanced by garlic oil, indicating that garlic oil may be a potential antibiotic enhancer.

Reduction of biofilm formation of Escherichia coli by targeting quorum sensing and adhesion genes using the CRISPR/Cas9-HDR approach, and its clinical application on urinary catheter

BACKGROUND

Escherichia coli is a common cause of biofilm-associated urinary tract infections (UTIs). Biofilm formation in E. coli is responsible for various indwelling medical device-associated infections, including catheter-associated urinary tract infections (CAUTIs). This study aimed to reduce biofilm formation of E. coli ATCC 25922 by knocking out genes involved in quorum sensing (QS) (luxS) and adhesion (fimH and bolA) using the CRISPR/Cas9-HDR approach.

METHOD

Single-guide RNAs (sgRNAs) were designed to target luxS, fimH and bolA genes. Donor DNA for homologous recombination was constructed to provide accurate repairs of double-strand breaks (DSBs). A biofilm quantification assay (crystal violet assay) was performed to quantify the biofilm formation of mutant and wild-type strains. Morphological changes in biofilm architecture were confirmed by scanning electron microscopy (SEM). Further application of the biofilm formation of mutant and wild-type strains on urinary catheter was tested.

RESULTS

Crystal violet assay showed that the biofilm formation of ΔfimH, ΔluxS, and ΔbolA strains was significantly reduced compared to the wild-type strain (P value < 0.001). The percentage of biofilm reduction of mutant strains was as follows: ΔluxS1 77.51 %, ΔfimH1 78.37 %, ΔfimH2 84.17 %, ΔbolA1 78.24 %, and ΔbolA2 75.39 %. Microscopic analysis showed that all mutant strains lack extracellular polymeric substances (EPS) production compared to the wild-type strain, which was embedded in its EPS matrix. The adherence, cell aggregation, and biofilm formation of wild-type strain on urinary catheters were significantly higher compared to ΔfimH, ΔluxS and ΔbolA strains.

CONCLUSION

Altogether, our results demonstrated that the knockout of luxS, fimH, and bolA genes reduced EPS matrix production, which is considered the main factor in the development, maturation, and maintenance of the integrity of biofilm. This pathway could be a potential strategy to disrupt E. coli biofilm-associated UTIs. This study suggests that CRISPR/Cas9-HDR system may provide an efficient and site-specific gene editing approach that exhibits a possible antibiofilm strategy through intervention with the QS mechanism and adhesion property to suppress biofilm formation associated with UTI catheter infections.

New tools to mitigate drug resistance in Enterobacteriaceae - Escherichia coli and Klebsiella pneumoniae

Treatment to common bacterial infections are becoming ineffective of late, owing to the emergence and dissemination of antibiotic resistance globally. Escherichia coli and Klebsiella pneumoniae are the most notorious microorganisms and are among the critical priority pathogens listed by WHO in 2017. These pathogens are the predominant cause of sepsis, urinary tract infections (UTIs), pneumonia, meningitis and pyogenic liver abscess. Concern arises due to the resistance of bacteria to most of the beta lactam antibiotics like penicillin, cephalosporin, monobactams and carbapenems, even to the last resort antibiotics like colistin. Preventing influx by modulation of porins, extruding the antibiotics by overexpression of efflux pumps, mutations of drug targets/receptors, biofilm formation, altering the drug molecules and rendering them ineffective are few resistance mechanisms that are adapted by Enterobacteriaeceae upon exposure to antibiotics. The situation is exacerbated due to the process of horizontal gene transfer (HGT), wherein the genes encoding resistance mechanisms are transferred to the neighbouring bacteria through plasmids/phages/uptake of free DNA. Carbapenemases, other beta lactamases and mcr genes coding for colistin resistance are widely disseminated leading to limited/no therapeutic options against those infections. Development of new antibiotics can be viewed as a possible solution but it involves major investment, time and labour despite which, the bacteria can easily adapt to the new antibiotic and evolve resistance in a relatively short time. Targeting the resistance mechanisms can be one feasible alternative to tackle these multidrug resistant (MDR) pathogens. Removal of plasmid (plasmid curing) causing resistance, use of bacteriophages and bacteriotherapy can be other potential approaches to combat infections caused by MDR E. coli and K. pneumoniae. The present review discusses the efficacies of these therapies in mitigating these infections, which can be potentially used as an adjuvant therapy along with existing antibiotics.

Attenuation of quorum sensing mediated virulence factors production and biofilm formation in Pseudomonas aeruginosa PAO1 by Colletotrichum gloeosporioides HM3

Signal dependent microbial communication in Pseudomonas aeruginosa PAO1 is a typical phenomenon mediated by acyl homo-serine lactone molecules that helps in developing biofilm and enhance antibiotic resistance. Microbial sources provide insight to the hidden treasure of secondary metabolites, and these structurally diversified chemical motifs can be used as antimicrobial and anti-infective agents. In the present study, endophytic fungus, Colletotrichum gloeosporioides HM3 isolated from Carica papaya leaves was explored for anti-infective potential against P. aeruginosa PAO1. The crude extract of C. gloeosporioides HM3 displayed bacteriostatic effect on P. aeruginosa PAO1 growth at 750 μg/ml concentration. A significant decline was observed in the production of quorum sensing regulated virulence factors, i.e. 56.32%, 62.54%, and 66.67% of pyocyanin, chitinase, and elastase enzyme, respectively. A drastic reduction in pathogenic determinant behaviour after treatment with crude extract of C. gloeosporioides HM3 i.e. EPS, rhamnolipid, and HCN production was noted. Light microscopy and CLSM analysis revealed that fungal extract treatment has reduced bacterial ability to form dense biofilm architecture. In silico analysis demonstrated the binding efficiency of bioactive compound, 4-(2,3-dimethoxybenzylidene)-3-methyl-1-(4-nitrophenyl)-2-pyrazolin-5-one, which is equipotent to the natural ligand and displayed a docking score of -5.436 kcal/mol with QS transcriptional regulator (LasR). Whereas the compound Acetamide, n-[tetrahydro-3-(phenylmethyl) thieno [3,4-d]thiazol-2 (3 h)-ylidene]-, s,s-dioxide exhibits a docking score of -4.088 kcal/mol (LasR) and -1.868 kcal/mol (RhlR) with cognate receptor proteins. Henceforth, the research report suggests C. gloeosporioides HM3 derived metabolites could be considered as a potential inhibitors of QS regulated virulence factors and biofilm production in P. aeruginosa PAO1.

Novel Opportunity to Reverse Antibiotic Resistance: To Explore Traditional Chinese Medicine With Potential Activity Against Antibiotics-Resistance Bacteria

Antibiotic resistance is becoming significantly prominent and urgent in clinical practice with the increasing and wide application of antibacterial drugs. However, developing and synthesizing new antimicrobial drugs is costly and time-consuming. Recently, researchers shifted their sights to traditional Chinese medicine (TCM). Here, we summarized the inhibitory mechanism of TCM herbs and their active ingredients on bacteria, discussed the regulatory mechanism of TCM on antibiotic-resistant bacteria, and revealed preclinical results of TCM herbs and their active components against antibiotic-resistant bacteria in mouse models. Those data suggest that TCM herbs and their effective constituents exhibit potential blockage ability on antibiotic-resistant bacteria, providing novel therapeutic ideas for reversing antibiotic resistance.

Phenotypic and genotypic characterization of biofilm forming, antimicrobial resistant, pathogenic Escherichia coli isolated from Indian dairy and meat products

Escherichia coli are commensal gastrointestinal microflora of humans, but few strains may cause food-borne diseases. Present study aimed to identify antimicrobial resistant (AMR), biofilm-forming E. coli from Indian dairy and meat products. A total of 32 E. coli isolates were identified and evaluated for biofilm-formation. EMC17, an E. coli isolate was established as a powerful biofilm-former that attained maximum biofilm-formation within 96 h on glass and stainless-steel surfaces. Presence and expression of virulence-associated genes (adhesins, invasins and polysaccharides) and ability to adhere and invade human liver carcinoma HepG2 cell lines implicates EMC17 to be pathotype belonging to Extra-intestinal Pathogenic E. coli (ExPEC). Antibiotic profiling of EMC17 identified it as multi-drug resistant (MDR) strain, possessing extended spectrum β-lactamases (ESBL's) and biofilm phenotype. Early production of quorum sensing molecules (AHLs) alongside EPS production facilitated early onset of biofilm formation by EMC17. Furthermore, the biofilm-forming genes of EMC17 were significantly upregulated 3-27 folds in the biofilm-state. This study showed prevalence of MDR, biofilm-forming, pathogenic E. coli in Indian dairy and meat products that potentially serve as reservoirs for transmission of antimicrobial-resistant (AMR) genes of bacteria from food to humans and pose serious food safety threat.

A comprehensive review of therapeutic approaches available for the treatment of cholera

Objectives

The oral rehydration solution is the most efficient method to treat cholera; however, it does not interfere in the action mechanism of the main virulence factor produced by Vibrio cholerae, the cholera toxin (CT), and this disease still stands out as a problem for human health worldwide. This review aimed to describe therapeutic alternatives available in the literature, especially those related to the search for molecules acting upon the physiopathology of cholera.

Key findings

New molecules have offered a protection effect against diarrhoea induced by CT or even by infection from V. cholerae. The receptor regulator cystic fibrosis channel transmembrane (CFTR), monosialoganglioside (GM1), enkephalinase, AMP-activated protein kinase (AMPK), inhibitors of expression of virulence factors and activators of ADP-ribosylarginine hydrolase are the main therapeutic targets studied. Many of these molecules or extracts still present unclear action mechanisms.

Conclusions

Knowing therapeutic alternatives and their molecular mechanisms for the treatment of cholera could guide us to develop a new drug that could be used in combination with the rehydration solution.

Anti-virulence activity of polyphenolic fraction isolated from Kombucha against Vibrio cholerae

The use of traditional foods and beverages or their bioactive compounds as anti-virulence agents is a new alternative method to overcome the increased global emergence of antimicrobial resistance in enteric pathogens. In the present study, we investigated the anti-virulence activity of a polyphenolic fraction previously isolated from Kombucha, a 14-day fermented beverage of sugared black tea, against Vibrio cholerae O1. The isolated fraction was mainly composed of the polyphenols catechin and isorhamnetin. The fraction, the individual polyphenols and the combination of the individual polyphenols significantly inhibited bacterial swarming motility and expression of flagellar regulatory genes motY and flaC, even at sub-inhibitory concentrations. The polyphenolic compounds also decreased bacterial protease secretion and mucin penetration in vitro. In vivo study revealed that the polyphenolic fraction significantly inhibited V. cholerae induced fluid accumulation in the rabbit ileal loop model and intestinal colonization in suckling mice model. Therefore, the anti-virulence activity of the Kombucha polyphenolic fraction involved inhibition of motility and protease secretion of V. cholerae, thus preventing bacterial penetration through the mucin layer as well as fluid accumulation and bacterial colonization in the intestinal epithelial cells. The overall results implied that Kombucha might be considered as a potential alternative source of anti-virulence polyphenols against V. cholerae. To the best of our knowledge, this is the first report on the anti-virulence activity of Kombucha, mostly attributed to its polyphenolic content.

Virulence factors of uropathogenic Escherichia coli (UPEC) and correlation with antimicrobial resistance

Background

Escherichia coli has found to be the predominant uropathogen (50–90%) in uncomplicated, community acquired urinary tract infection (UTI). Uropathogenic Escherichia coli (UPEC) express a multitude of virulence factors, which enable the bacteria to establish UTI. The objective of this study was to evaluate the presence of different phenotypic virulence markers in UPEC isolates and determine their correlation with antibiotic resistance pattern.

Results

Out of 105 patients, 56 (53%) were females and 49 (47%) were males. The age of the patients in the study ranged from 18 years to 87 years and majority of the patients belonged to the age group 20–29 years. Virulence factor was observed in 65% (n = 69) of UPEC and 20% (n = 22) of control isolates (P = 0.0001). Haemolysin production was observed in 34(32.3%) of uroisolates and 12 (11.4%) of control strain. Similarly, 62% of UPEC and 1% of control produced biofilm (P = 0.0001). The expression of Mannose-resistant hemagglutinin (MRHA) and mannose-sensitive hemagglutinin (MSHA) in uroisolates were 52.3% (n = 55) and 5.7% (n = 6) respectively, whereas in faecal isolates, 8.5% (n = 9) expressed MRHA and none produced MSHA. Antimicrobial resistance showed a high degree of resistance towards ampicillin, cotrimoxazole and norfloxacin. The resistance was observed in significant higher degree in biofilm formers as compared to non-formers. MDR and ESBL was observed in 51 and 46% of test strains and 9 and 7.6% of control strains (P = 0.0001).

Conclusion

A significant association between virulence factors of UPEC and antimicrobial resistance in UPEC was present. Routine testing of these factors and co-relation with AMR is recommended. These findings will certainly help understand the pathogenicity and proper management of UTI patients, thus decreasing the improper use of antibiotics.

Biofilms in the Food Industry: Health Aspects and Control Methods

Diverse microorganisms are able to grow on food matrixes and along food industry infrastructures. This growth may give rise to biofilms. This review summarizes, on the one hand, the current knowledge regarding the main bacterial species responsible for initial colonization, maturation and dispersal of food industry biofilms, as well as their associated health issues in dairy products, ready-to-eat foods and other food matrixes. These human pathogens include Bacillus cereus (which secretes toxins that can cause diarrhea and vomiting symptoms), Escherichia coli (which may include enterotoxigenic and even enterohemorrhagic strains), Listeria monocytogenes (a ubiquitous species in soil and water that can lead to abortion in pregnant women and other serious complications in children and the elderly), Salmonella enterica (which, when contaminating a food pipeline biofilm, may induce massive outbreaks and even death in children and elderly), and Staphylococcus aureus (known for its numerous enteric toxins). On the other hand, this review describes the currently available biofilm prevention and disruption methods in food factories, including steel surface modifications (such as nanoparticles with different metal oxides, nanocomposites, antimicrobial polymers, hydrogels or liposomes), cell-signaling inhibition strategies (such as lactic and citric acids), chemical treatments (such as ozone, quaternary ammonium compounds, NaOCl and other sanitizers), enzymatic disruption strategies (such as cellulases, proteases, glycosidases and DNAses), non-thermal plasma treatments, the use of bacteriophages (such as P100), bacteriocins (such us nisin), biosurfactants (such as lichenysin or surfactin) and plant essential oils (such as citral- or carvacrol-containing oils).

DRDO Herbal Technologies: Military and Civil Applications

The novel herbal technologies developed by India’s Defence Research and Development Organization are discussed with a view to improving the lives of soldiers and civilians. The life sciences laboratories of DRDO are engaged in R&D with the aim to develop processes, products and technologies and effective strategies to protect and enhance the operational efficiency of the Indian Armed Forces. Over the last five decades, the endeavours have resulted in creating specialized human capital through selection and training; enhancing efficiency through customized nutrition; optimizing human efficiency through traditional systems; optimizing performance through human engineering approach; protecting against health hazards like CBRN and vectors; reducing combat stress by counselling, training and resilience building; reinforcing adaptation through acclimatization processes and saving lives through life support systems. Several technologies with holistic and pragmatic applications for defence and civil sector from a herbal perspective are presented.

Development of a Novel Herbal Formulation To Inhibit Biofilm Formation in Toxigenic Vibrio cholerae

Vibrio cholerae, a causative agent of the waterborne disease cholera, still threatens a large proportion of world's population. The role of biofilm formation in V. cholerae pathogenesis is well established, as it provides the bacterium enhanced tolerance to antimicrobial agents and increased transmission. In the present study, four medicinal plants used in traditional medicines with antidiarrheal properties were evaluated for its antibiofilm activity. Methanol extracts of these plants (Centella asiatica, Elephantopus scaber, Camellia sinensis, and Holarrhena antidysenterica) showed promising antibiofilm activity against V. cholerae with crystal violet and air-liquid interface coverslip assays. Results revealed that C. asiatica, E. scaber, C. sinensis, and H. antidysenterica extracts significantly inhibited biofilm formation by approximately 75, 76, 78, and 55% at concentrations of 3, 2, 1, and 0.6 mg/mL, respectively. A promising antibiofilm activity of ∼89% inhibition at 1.5 mg/mL concentration was observed when a combination of E. scaber and C. sinensis was used. The herbal extracts were thermostable at a temperature range of 40 to 100°C. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay revealed that the viability of bacteria was not affected by treatment with these plant extracts. Gene expression studies revealed that extracts of H. antidysenterica leaf, H. antidysenterica bark, and the whole plant of E. scaber and C. asiatica down-regulate aphA or aphB, the major regulator genes modulating both virulence and biofilm formation. Hence, we propose that these herbal combinations could serve as a multifaceted approach to combat the pathogen and also, in turn, reduce antimicrobial resistance development.

The Complex Relationship between Virulence and Antibiotic Resistance

Antibiotic resistance, prompted by the overuse of antimicrobial agents, may arise from a variety of mechanisms, particularly horizontal gene transfer of virulence and antibiotic resistance genes, which is often facilitated by biofilm formation. The importance of phenotypic changes seen in a biofilm, which lead to genotypic alterations, cannot be overstated. Irrespective of if the biofilm is single microbe or polymicrobial, bacteria, protected within a biofilm from the external environment, communicate through signal transduction pathways (e.g., quorum sensing or two-component systems), leading to global changes in gene expression, enhancing virulence, and expediting the acquisition of antibiotic resistance. Thus, one must examine a genetic change in virulence and resistance not only in the context of the biofilm but also as inextricably linked pathologies. Observationally, it is clear that increased virulence and the advent of antibiotic resistance often arise almost simultaneously; however, their genetic connection has been relatively ignored. Although the complexities of genetic regulation in a multispecies community may obscure a causative relationship, uncovering key genetic interactions between virulence and resistance in biofilm bacteria is essential to identifying new druggable targets, ultimately providing a drug discovery and development pathway to improve treatment options for chronic and recurring infection.

In vivo anti-arthritic efficacy of Camellia sinensis (L.) in collagen induced arthritis model

BACKGROUND

Rheumatoid arthritis (RA), an autoimmune inflammatory disorder with synovial hyperplasia, destruction of cartilage, bone damage is often associated with risk of infections. Such risk could be attributed towards usage of immunosuppressive agents. Thus, the present study was undertaken to evaluate the anti-arthritic efficacy of aquo-alcoholic extract of Camellia sinensis (L.).

MATERIAL AND METHODS

Dried leaves of Camellia sinensis (L.) or Cs were filtered and extracted in 1:1 aqueous: ethanol by Soxhlet apparatus followed by lyophilization and spray drying to develop amorphous powder. Four different oral doses (50, 100, 200, 400mg/kg/body wt.) of aquo-alcoholic extract were evaluated for anti-edematogenic effect in collagen induced arthritis model. The selected anti-arthritic doses of Cs were evaluated for the oxidative stress markers like Glutathione [5-5'dithio-bis-2-nitrobenzoicacid (DTNB)], Superoxide dismutase [Epinephrine], Catalase [Hydrogen peroxide], Lipid peroxidation [Thiobarbituric acid reactive substance (TBARS)], Nitric oxide [Griess reagents:Nitrobluetetrazolium], Articular elastase [N-methoxysuccinyl-Ala-Ala-Pro- Val p-nitroanilide] in joints followed by haematological evaluation including RBC, WBC, Haemoglobin, platelets and haematocrit. To validate these biochemical changes, the radiological and histopathological (Haematoxylin & Eosin) evaluation was also conducted.

RESULTS

The selected anti-arthritic dose of Cs i.e. 400mg/kg/body wt. (∼60% anti-arthritic efficacy on 35th day) could be attributed towards significant (p<0.05) increase in the levels of enzymatic (Superoxide dismutase and Catalase) and non-enzymatic (Glutathione) antioxidants by 34%, 59% and 50% respectively. Simultaneously, the significant (p<0.05) reduction of lipid peroxides, nitrite radical and elastase activity by 32%, 45% & 32% respectively as compare to control indicated overall decrease in oxidative stress. Haematological evaluation revealed restoration of RBC, WBC and platelets level in treatment group. The confirmatory analysis utilizing radiological and histological assessment showed alleviation of joint deformity, tissue swelling, pannus formation and neutrophils infiltration in treatment group as compared to collagen induced arthritis.

CONCLUSION

The analysis showed that Cs can play an effective role in reduction of oxidative stress by modulating levels of antioxidants, reducing levels of free radicals while restoring normal haematopoietic cascade as observed in collagen induced arthritis model. Thus, the cumulative dose impact of 400mg/kg body wt., over a period of 14days also found extremely effective in terms of safeguarding their structural conformity against such auto-immune disorder.

Anti-hemolytic, hemagglutination inhibition and bacterial membrane disruptive properties of selected herbal extracts attenuate virulence of Carbapenem Resistant Escherichia coli

Expression of a multitude of virulence factors by multi-drug resistant microbial strains, e.g., Carbapenem Resistant Escherichia coli (Family: Enterobacteriaceae; Class: Gammaproteobacteria), is responsible for resistance against beta-lactam antibiotics. Hemolysin production and induction of hemagglutination by bacterial surface receptors inflicts direct cytotoxicity by destroying host phagocytic and epithelial cells. We have previously reported that Berberis aristata, Camellia sinensis, Cyperus rotundus Holarrhena antidysenterica and Andrographis paniculata are promising herbal leads for targeting Carbapenem resistant Escherichia coli. These herbal leads were analyzed for their anti-hemolytic potential by employing spectrophotometric assay of hemoglobin liberation. Anti-hemagglutination potential of the extracts was assessed by employing qualitative assay of visible RBC aggregate formation. Camellia sinensis (PTRC-31911-A) exhibited anti-hemolytic potential of 73.97 ± 0.03%, followed by Holarrhena antidysenterica (PTRC-8111-A) i.e., 68.32 ± 0.05%, Berberis aristata (PTRC-2111-A) i.e., 60.26 ± 0.05% and Cyperus rotundus (PTRC-31811-A) i.e., 53.76 ± 0.03%. Comprehensive, visual analysis of hemagglutination inhibition revealed that only Berberis aristata (PTRC-2111-A) and Camellia sinensis (PTRC-31911-A) exhibited anti-hemagglutination activity. However, Andrographis paniculata (PTRC-11611-A) exhibited none of the inhibitory activities. Furthermore, the pair wise correlation analysis of the tested activities with quantitative phytochemical descriptors revealed that an increased content of alkaloid; flavonoids; polyphenols, and decreased content of saponins supported both the activities. Additionally, flow cytometry revealed that cell membrane structures of CRE were damaged by extracts of Berberis aristata (PTRC-2111-A) and Camellia sinensis (PTRC-31911-A) at their respective Minimum Inhibitory Concentrations, thereby confirming noteworthy antibacterial potential of both these extracts targeting bacterial membrane; hemolysin and bacterial hemagglutination.