Altered Molecular Attributes and Antimicrobial Resistance Patterns of Vibrio cholerae O1 El Tor Strains Isolated from the Cholera Endemic Regions of India

AIMS

The present study aimed to document the comparative analysis of differential hyper-virulent features of Vibrio cholerae O1 strains isolated during 2018 from cholera endemic regions in Gujarat and Maharashtra (Western India) and West Bengal (Eastern India).

METHODS AND RESULTS

A total of 87 V. cholerae O1 clinical strains from Western India and 48 from Eastern India were analyzed for a number of biotypic and genotypic features followed by antimicrobial resistance (AMR) profile. A novel PCR was designed to detect a large fragment deletion in the Vibrio seventh pandemic island II (VSP-II) genomic region, which is a significant genetic feature of the V. cholerae strains that has caused Yemen cholera outbreak. All the strains from Western India were belong to the Ogawa serotype, polymyxin B-sensitive, hemolytic, had a deletion in VSP-II (VSP-IIC) region and carried Haitian genetic alleles of ctxB, tcpA and rtxA. Conversely, 14.6% (7/48) of the strains from Eastern India belonged to the Inaba serotype, polymyxin B-resistant, non-hemolytic, harbored VSP-II other than VSP-IIC type, classical ctxB, Haitian tcpA and El Tor rtxA alleles. Resistance to tetracycline and chloramphenicol has been observed in strains from both the regions.

CONCLUSIONS

This study showed hyper-virulent, polymyxin B-sensitive epidemic causing strains in India along with the strains with polymyxin B-resistant and non-hemolytic traits that may spread and cause serious disease outcome in future.

SIGNIFICANCE AND IMPACT OF THE STUDY

The outcomes of this study can help to improve the understanding of the hyper-pathogenic property of recently circulating pandemic V. cholerae strains in India. A special attention is also needed on the monitoring of AMR surveillance because V. cholerae strains are losing susceptibility to many antibiotics used as a second line of defense in the treatment of cholera.

Antimicrobial loaded gum odina - gelatin based biomimetic spongy scaffold for accelerated wound healing with complete cutaneous texture

The main objective of this study was to assess the therapeutic activity of gum odina and gelatin based biomimetic scaffold which was previously established as an excellent wound dressing material. In the accelerated stability study, the changes in physicochemical properties were found to be negligible. The cytotoxicity studies were carried out in-vitro and the results showed that upto 90% of the cells remained viable in presence of the scaffold, confirming its biocompatibility. Moreover, results depicted the superior ability of the scaffold to promote cutaneous healing by increasing the rate of wound contraction (about 98%), granulation formation, collagen deposition and formation of an intact epidermis within 18 days. A satisfactory amount of hydroxyproline (240.2 ± 6.67 μg/100 mg tissue) in scaffold treated groups at 21 days ensured the significant deposition of collagen to re-epithelialization. Further it can be hypothesized that the controlled levels of antioxidant enzymes (SOD, CAT) to diminish the oxidative stress in the wounded sites were due to the innate antioxidant properties of both blank and drug loaded scaffold. These results strongly indicated that the prepared scaffolds have strong potential for biomedical applications and it may serve as promising candidate for the next generation of wound treatment systems.

A Mouse Model of Helicobacter pylori Infection

Infection with Helicobacter pylori (H. pylori) is of great distress because of its vital role in the pathogenesis of chronic gastritis, peptic ulcers, and in the multi-step carcinogenic process of gastric cancer. The increasing antibiotic resistance pattern of H. pylori worldwide has prompted the World Health Organization to put this organism in the priority pathogens list. To study the disease biology, evaluation of drugs, treatment outcome and to come up with probable vaccination strategies, competent animal models that reproduce the signature of human infection are essential. Initial reports about animal colonization with H. pylori have shown significant heterogeneity, to such an extent that Barry Marshall, Nobel laureate for the discovery of H. pylori , infected himself with the bacterium to show its involvement in acute gastric illness. A paradigm-shift discovery of the H. pylori mouse-adapted strain SS1 has opened the avenues of research regarding the organism and its pathogenicity. Although the mouse model of H. pylori infection is being utilized all over the world, there are certain issues that need awareness and specific information to achieve successful, consistent colonization with symptoms resembling human. This chapter details an established and reliable protocol for the development of a competent mouse model for H. pylori infection leading to various gastro-intestinal diseases.

Enzymatic synthesis of lipophilic lutein-PUFA esters and assessment of their stabilization potential in EPA-DHA rich fish oil matrix

The objective of the present study was to synthesize ω-3 polyunsaturated fatty acid esters of lutein and to evaluate if esterification can stabilize the both bioactive molecules. Both ω-3 polyunsaturated fatty acid and lutein are prone towards auto-oxidation in their free form. Free lutein extracted from the marigold petals was enzymatically esterified using Candida antarctica NS435 Lipase B, with the ω-3 long-chain polyunsaturated fatty acids. The lutein esters were purified, characterized and finally assessed for their protective role against oxidative degradation in bulk fish oil matrix. The antioxidative effect of these esters was compared with commercial antioxidants of natural origin, i.e., α-tocopherol and a synthetic antioxidant, i.e., tert-butylhydroquinone, at a dosage of 200 mg/L. Both free lutein and lutein-polyunsaturated fatty acid ester had significantly promoted the oxidative stability of bulk fish oil. But based on dose-response relationship, lutein-polyunsaturated fatty acid ester was found to be more efficient than free lutein, in protecting fish oil from secondary oxidation, thereby augmenting their shelf life. Given the high nutraceutical value, potent antioxidative potential and organic origin, it is only relevant to incorporate lutein esters as natural preservative and stabilizers in edible oils.

Treatment of cosmetic effluent in different configurations of ceramic UF membrane based bioreactor: Toxicity evaluation of the untreated and treated wastewater using catfish (Heteropneustes fossilis)

Extensive usage of pharmaceutical and personal care products (PPCPs) and their discharge through domestic sewage have been recently recognized as a new generation environmental concern which deserves more scientific attention over the classical environmental pollutants. The major issues of this type of effluent addressed in this study were its colour, triclosan and anionic surfactant (SDS) content. Samples of cosmetic effluent were collected from different beauty treatment salons and spas in and around Kolkata, India and treated in bioreactors containing a bacterial consortium isolated from activated sludge samples collected from a common effluent treatment plant. Members of the consortium were isolated and identified as Klebsiella sp., Pseudomonas sp., Salmonella sp. and Comamonas sp. The biotreated effluent was subjected to ultrafiltration (UF) involving indigenously prepared ceramic membranes in both side-stream and submerged mode. Analysis of the MBR treated effluent revealed 99.22%, 98.56% and 99.74% removal of colour, triclosan and surfactant respectively. Investigation of probable acute and chronic cyto-genotoxic potential of the untreated and treated effluents along with their possible participation in triggering oxidative stress was carried out with Heteropneustes fossilis (Bloch). Comet formation recorded in both liver and gill cells and micronucleus count in peripheral erythrocytes of individuals exposed to untreated effluent increased with duration of exposure and was significantly higher than those treated with UF permeates which in turn neared control levels. Results of this study revealed successful application of the isolated bacterial consortium in MBR process for efficient detoxification of cosmetic effluent thereby conferring the same suitable for discharge and/or reuse.

Application of isolated bacterial consortium in UMBR for detoxification of textile effluent: comparative analysis of resultant oxidative stress and genotoxicity in catfish (Heteropneustes fossilis) exposed to raw and treated effluents

A bacterial consortium isolated from activated sludge was identified to be Bacillus sp., Pseudomonas sp., Shigella sp. and E. coli. and was found capable of 98.62 % decolourization of highly toxic textile effluent, when applied in an ultrafiltration (UF) membrane bioreactor (UMBR). Ceramic capillary UF membranes prepared over low cost support proved to be highly efficient in adverse experimental conditions. The UMBR permeate and untreated textile effluent (40 % (v/v)) was then used to treat Heteropneustes fossilis for a comparative assessment of their toxicity. Micronucleus count in peripheral blood erythrocytes and comet assay carried out in liver and gill cells showed significantly lower nuclear and tissue specific DNA damage respectively in organisms exposed to membrane permeate and was further supported by considerably lower oxidative stress response enzyme activities in comparison to raw effluent treated individuals. The results indicate efficient detoxification of textile effluent by the UMBR treatment using the isolated bacterial consortium.

Groundwater Arsenic Contamination in West Bengal: Current Scenario, Effects and Probable Ways of Mitigation

During the past two decades, Arsenic (As) contamination via groundwater has become a serious issue worldwide and is now a major concern in the Indo-Bangladesh Gangetic delta. Arsenic enters human body through contaminated groundwater consumed as drinking water. Food safety in this region is also facing severe consequences as bio-accumulation of Arsenic is occurring in food crops irrigated with As-contaminated water. Chronic exposure to Arsenic can cause not only cancerous and non-cancer health effects. Reports suggest that about 20 % population in West Bengal is highly affected. Various techniques are being introduced to provide arsenic-free drinking water at an affordable cost. But a rigorous change in habit and mind set for procuring safe drinking water in those surviving in As-contaminated zones is the most essential step towards curbing the fatal consequences of As exposure. Harvesting rain water and utilization of proper purification techniques can be considered a possible alternative of safe drinking water.

Groundwater Arsenic Contamination in West Bengal: Current Scenario, Effects and Probable Ways of Mitigation

During the past two decades, Arsenic (As) contamination via groundwater has become a serious issue worldwide and is now a major concern in the Indo-Bangladesh Gangetic delta. Arsenic enters human body through contaminated groundwater consumed as drinking water. Food safety in this region is also facing severe consequences as bio-accumulation of Arsenic is occurring in food crops irrigated with As-contaminated water. Chronic exposure to Arsenic can cause not only cancerous and non-cancer health effects. Reports suggest that about 20 % population in West Bengal is highly affected. Various techniques are being introduced to provide arsenic-free drinking water at an affordable cost. But a rigorous change in habit and mind set for procuring safe drinking water in those surviving in As-contaminated zones is the most essential step towards curbing the fatal consequences of As exposure. Harvesting rain water and utilization of proper purification techniques can be considered a possible alternative of safe drinking water.

Detection of New Delhi metallo-beta-lactamase and extended-spectrum beta-lactamase genes in Escherichia coli isolated from mastitic milk samples

In this study, eight Escherichia coli isolates were obtained from milk samples of dairy cattle suffering from clinical/subclinical mastitis. Isolates were characterized for antimicrobial resistance traits and virulence genes. Results revealed that one isolate was harbouring New Delhi metallo-beta-lactamase gene (blaNDM ). Cloning and sequencing of the PCR amplicon confirmed the identity of the gene (GenBank accession no. KC769583) having 100% homology with blaNDM-5 (GenBank accession no. JN104597.1), and this isolate was susceptible to colistin, chloramphenicol and tetracycline only. Moreover, another isolate carried extended-spectrum beta-lactamase (ESBL) gene - blaCTX-M , and all isolates possessed blaTEM gene. Of the eight isolates, only one isolate was positive for shiga toxin gene (stx2), and none were harbouring stx1 gene. Occurrence of New Delhi metallo-beta-lactamase (blaNDM ) in one E. coli isolate and ESBL genes in other isolates poses a potential threat to human health following possible entry and spread through food chain.

Giant room temperature magnetoimpedance in La0.7Ba0.15Sr0.15MnO3 and development of a sensitive position detector

Observation of room temperature giant magnetoimpedance in La0.7Ba0.15Sr0.15MnO3 compound having nanometric grain size is reported under low magnetic field and over the frequency range between 50 KHz and 15 MHz. Both the resistive and reactive components of impedance increase with increasing frequency due to skin effect of the metallic state below T(C). Above a critical frequency (1 MHz), a sharp increase in both R and X and hence Z is observed. The applied magnetic field influences the impedance by affecting the penetration depth via the transverse permeability and gives rise to large magnetoimpedance (approximately 70%) at low fields up to 0.1 T. Magnetoimpedance of La0.7Ba0.15Sr0.15MnO3 compound display major change (approximatley 61%) between 0.02 and 0.035 T and appears to originate due to the spin alignment of the charge carriers across the grain boundaries. At fields > 0.1 T, magnetoimpedance displays near saturation, corresponding to the completion of the spin alignment across the grain boundaries. An unique scaling behavior has been observed for field dependence of magnetoimpedance at various frequencies, which could be well accounted by a phenomenological model. Feasibility of the development of a sensitive linear position sensor is also demonstrated.

Magnetocaloric effect in potassium doped lanthanum manganite perovskites prepared by a pyrophoric method

The magnetocaloric effect (MCE) in fine grained perovskite manganites of the type La(1-x)K(x)MnO(3) (0<x<0.15) prepared by a pyrophoric method has been investigated. Potassium addition in lanthanum manganite enhances the Curie temperature (T(C)) of the system from 260.4 K (x = 0.05) to 309.7 K (x = 0.15). A large magnetic entropy change associated with the ferromagnetic-paramagnetic transition has been observed. The maximum entropy change |ΔS(M)(Max)| in an applied field of 1 T shows an enhancement by ∼10% with increase in K content up to x = 0.15. La(0.85)K(0.15)MnO(3) exhibits the largest |ΔS(M)(Max)| value of 3.00 J kg(-1) K(-1) at 310 K amongst the compounds investigated. Moreover, the maximum magnetic entropy change exhibits a linear dependence with applied magnetic field. The estimated adiabatic temperature change at T(C) and at 1 T field also increases with K doping, being a maximum of 2.1 K for the La(0.85)K(0.15)MnO(3) compound. The relative cooling power (RCP) of La(1-x)K(x)MnO(3) compounds is estimated to be about one-third of that of the prototype magnetic refrigerant material (pure Gd). However, La(1-x)K(x)MnO(3) compounds possess an MCE around room temperature, which is comparable to that of Gd. Further, tailoring of their T(C), higher chemical stability, lower eddy current heating and lower cost of synthesis are some of the attractive features of K doped lanthanum manganites that are advantageous for a magnetic refrigerant. The temperature dependence of the magnetic entropy change (ΔS(M)) measured under various magnetic fields is explained fairly well using the Landau theory of phase transitions. Contributions of magnetoelastic and electron interaction are found to have a strong influence in the magnetocaloric effect of manganites.

Agricultural practices and personal hygiene among agricultural workers in a rural area of Howrah district, West Bengal

The study attempted to assess agricultural practices and personal hygiene among 100 agricultural workers in a rural area of West Bengal in 1999. 69% of the study population was marginal farmer with less than 2 acres of land. Organophosphorus group of pesticides were most commonly used pesticides (68%); spraying was irregular in nature (98%), through semiautomatic sprayer (99%) and only 5% used any special dress while spraying pesticides. 40% of workers used to store pesticides either in living room or in food storage area. 88% of them did not take any food during work with pesticides, only 37% used to take regular bath after working with pesticides but regular hand washing was practiced by all of them.

Work related physical exertion and spontaneous abortion

A retrospective cohort study was undertaken among 100 women workers of 35-40 years of age to elicit the risk of spontaneous abortion. Comparison was made with a matched control group of 100 non-working women. Employed women were found at increased risk of spontaneous abortion than the control group. The difference was found statistically significant at p < 0.05, Odds ratio being 1.50 and AR% being 33.14. According to gravidity also, abortion was found to be significantly raised in working women after their joining service for first 3rd - 4th gravida. The risk then fell, to raise again for 8th or more gravida.