A comprehensive review of environmental fate and degradation of fipronil and its toxic metabolites.

The use of pesticides to increase crop production has become one of the inevitable components of modern agriculture. Fipronil, a phenylpyrazoles insecticide, is one of the most widely used, systemic, broad-spectrum insecticides. Owing to its unique mode of action and selective toxicity, it was once regarded as safer alternatives to more toxic and persistent organochlorine insecticides. However, with the increased use, many studies have reported the toxicity of fipronil and its metabolites in various non-target organisms during the last two decades. Currently, it is regarded as one of the most persistent and lipophilic insecticides in the market. In the environment, fipronil can undergo oxidation, reduction, hydrolysis, or photolysis to form fipronil sulfone, fipronil sulfide, fipronil amide, or fipronil desulfinyl respectively. These metabolites except fipronil amide are more or less toxic and persistent than fipronil and have been reported from diverse environmental samples. Recently many studies have focused on the degradation and removal of fipronil residues from the environment. However, a comprehensive review summarizing and combining these recent findings is lacking. In the present review, we evaluate, summarize, and combine important findings from recent degradation studies of fipronil and its metabolites. An attempt has been made to elucidate the possible mechanism and pathways of degradation of fipronil and its toxic metabolites.

Potential of formulated Dyadobacter jiangsuensis strain 12851 for enhanced bioremediation of chlorpyrifos contaminated soil.

Chlorpyrifos (O, O-diethyl O-3, 5, 6-trichloropyridin-2-yl phosphorothioate) is a toxic and chlorinated organic contaminant in soils across the globe. The present study examines the chlorpyrifos (CP) degrading potential of gram-negative bacterium Dyadobacter jiangsuensis (MTCC 12851), to be a promising and sustainable remedial approach. The proliferation of D. jiangsuensis in the chlorpyrifos spiked minimal salt media indicated the ability of this strain to utilize CP as a sole carbon source and also confirmed the utilization of 3,5,6- trichloro-2-pyridinyl (TCP) through silver nitrate assay. The strain 12851 degraded 80.36% and 76.93% chlorpyrifos (CP) in aqueous medium and soil environment, respectively. The water dispersible granules (WDG) of 45% (v/w) inoculum (bacterial suspension) were developed using talcum powder, acacia gum and alginic acid as key ingredients. The formulated strain (12851) achieved 21.13% enhanced CP degradation in soil under microcosm condition as compared to the unformulated one on 15th day of the treatment. The intermediate metabolites namely 3,5,6-trichloro-2-pyridinol (TCP), tetrahydropyridine, thiophosphate and phenol, 1, 3-bis (1,1-dimethylethyl) were detected during the CP degradation. The current investigation reveals D. jiangsuensis as a potential microbe for CP degradation and opens up the possibility of exploiting its formulations to remediate the CP polluted soils.

Enhancing hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine (RDX) remediation through water-dispersible Microbacterium esteraromaticum granules.

In the current manuscript, we explored the remediation potential of Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) by Gram-positive Microbacterium esteraromaticum 12849. The strain detoxified 70.9 and 63.93% RDX in minimal nutrient medium and soil, respectively. Subsequently, the strain 12849 was formulated in form of water-dispersible granules (WDG) using talcum powder and alginic acid as inert ingredients. During the microcosm study, WDG exhibited 8.98% enhanced RDX degradation in contrast to the unformulated Microbacterium esteraromaticum. The LC-MS analysis revealed the presence of two intermediates, namely N-methyl-N, N'-dinitromethanediamine, and methylenedintramine, during the RDX degradation by strain 12849 in soil. Interestingly, no significant difference was observed in the rate of RDX degradation by strain 12849 due to the formulation process. The first-order kinetics was seen in RDX degradation with a degradation coefficient of 0.04 and 0.0339 day-1 by formulated and unformulated strain, respectively. The current investigation implies M. esteraromaticum as a potential microbe for RDX degradation and opens up the possibility of exploiting it in its effective WDG form for explosive contaminated sites.

Identification of enzyme(s) capable of degrading endosulfan and endosulfan sulfate using in silico techniques.

Endosulfan is one of the most widely used organochlorine cyclodiene insecticides. Microbial oxidation of endosulfan forms endosulfan sulfate, which is more or less toxic and persistent as endosulfan. Due to lack of specificity and efficiency of microbial bioremediation technique in the field conditions, enzymatic bioremediation is receiving huge attention to clean-up the environment. In the present study, X-ray crystal structures of enzymes from Brookhaven Protein Data Bank were screened for their potential to degrade endosulfan and endosulfan sulfate using molecular docking and molecular dynamics simulation techniques. A phenol hydroxylase, 1PN0 from Trichosporon cutaneum was found to have the potential to degrade both α-endosulfan and endosulfan sulfate while a bacterial CotA laccase, 3ZDW from Bacillus subtilis has the potential to degrade α-endosulfan. The in silico result correlate with in vitro degradation study using two different strains of Trichosporon cutaneum. In vitro degradation study found that the fungal strain was capable of degrading 60.36% α-endosulfan, 70.73% ß-endosulfan, and 52.08% endosulfan sulfate. The presence of phenol hydroxylase inhibitor in the sulfur-free medium with endosulfan and endosulfan sulfate as sole sulfur source inhibits the growth of both the fungal strains. Such in silico techniques can provide an easy and reliable way to speed up the development of bioremediation processes through rapid identification of potential enzymes and microbes to counter the ever-increasing number of toxic compounds in the environment.

Combining Healthcare-Based and Participatory Approaches to Surveillance: Trends in Diarrheal and Respiratory Conditions Collected by a Mobile Phone System by Community Health Workers in Rural Nepal.

BACKGROUND: Surveillance systems are increasingly relying upon community-based or crowd-sourced data to complement traditional facilities-based data sources. Data collected by community health workers during the routine course of care could combine the early warning power of community-based data collection with the predictability and diagnostic regularity of facility data. These data could inform public health responses to epidemics and spatially-clustered endemic diseases. Here, we analyze data collected on a daily basis by community health workers during the routine course of clinical care in rural Nepal. We evaluate if such community-based surveillance systems can capture temporal trends in diarrheal diseases and acute respiratory infections. METHODS: During the course of their clinical activities from January to December 2013, community health workers recorded healthcare encounters using mobile phones. In parallel, we accessed condition-specific admissions from 2011-2013 in the hospital from which the community health program was based. We compared diarrhea and acute respiratory infection rates from both the hospital and the community, and assigned three categories of local disease activity (low, medium, and high) to each week in each village cluster with categories determined by tertiles. We compared condition-specific mean hospital rates across categories using ANOVA to assess concordance between hospital and community-collected data. RESULTS: There were 2,710 cases of diarrhea and 373 cases of acute respiratory infection reported by community health workers during the one-year study period. At the hospital, the average weekly incidence of diarrhea and acute respiratory infections over the three-year period was 1.8 and 3.9 cases respectively per 1,000 people in each village cluster. In the community, the average weekly rate of diarrhea and acute respiratory infections was 2.7 and 0.5 cases respectively per 1,000 people. Both diarrhea and acute respiratory infections exhibited significant differences between the three categories of disease rate burden (diarrhea p = 0.009, acute respiratory infection p = 0.001) when comparing community health worker-collected rates to hospital rates. CONCLUSION: Community-level data on diarrhea and acute respiratory infections modestly correlated with hospital data for the same condition in each village each week. Our experience suggests that community health worker-collected data on mobile phones may be a feasible adjunct to other community- and healthcare-related data sources for surveillance of such conditions. Such systems are vitally needed in resource-limited settings like rural Nepal.

Strengthening Nepal's Female Community Health Volunteer network: a qualitative study of experiences at two years.

BACKGROUND: Nepal's Female Community Health Volunteer (FCHV) program has been described as an exemplary public-sector community health worker program. However, despite its merits, the program still struggles to provide high-quality, accessible services nation-wide. Both in Nepal and globally, best practices for community health worker program implementation are not yet known: there is a dearth of empiric research, and the research that has been done has shown inconsistent results. METHODS: Here we evaluate a pilot program designed to strengthen the Nepali government's FCHV network. The program was structured with five core components: 1) improve local FCHV leadership; 2) facilitate structured weekly FCHV meetings and 3) weekly FCHV trainings at the village level; 4) implement a monitoring and evaluation system for FCHV patient encounters; and 5) provide financial compensation for FCHV work. Following twenty-four months of program implementation, a retrospective programmatic evaluation was conducted, including qualitative analysis of focus group discussions and semi-structured interviews. RESULTS: Qualitative data analysis demonstrated that the program was well-received by program participants and community members, and suggests that the five core components of this program were valuable additions to the pre-existing FCHV network. Analysis also revealed key challenges to program implementation including geographic limitations, literacy limitations, and limitations of professional respect from healthcare workers to FCHVs. Descriptive statistics are presented for programmatic process metrics and costs throughout the first twenty four months of implementation. CONCLUSIONS: The five components of this pilot program were well-received as a mechanism for strengthening Nepal's FCHV program. To our knowledge, this is the first study to present such data, specifically informing programmatic design and management of the FCHV program. Despite limitations in its scope, this study offers tangible steps forward for further research and community health worker program improvement, both within Nepal and globally.

Implementing a systems-oriented morbidity and mortality conference in remote rural Nepal for quality improvement.

PROBLEM: In hospitals in rural, resource-limited settings, there is an acute need for simple, practical strategies to improve healthcare quality. SETTING: A district hospital in remote western Nepal. KEY MEASURES FOR IMPROVEMENT: To provide a mechanism for systems-level reflection so that staff can identify targets for quality improvement in healthcare delivery. Strategies for change To develop a morbidity and mortality conference (M&M) quality improvement initiative that aims to facilitate structured analysis of patient care and identify barriers to providing quality care, which can subsequently be improved. DESIGN: The authors designed an M&M involving clinical and non-clinical staff in conducting root-cause analyses of healthcare delivery at their hospital. Weekly conferences focus on seven domains of causal analysis: operations, supply chain, equipment, personnel, outreach, societal, and structural. Each conference focuses on assessing the care provided, and identifying ways in which services can be improved in the future. EFFECTS OF CHANGE: Staff reception of the M&Ms was positive. In these M&Ms, staff identified problem areas in healthcare delivery and steps for improvement. Subsequently, changes were made in hospital workflow, supply procurement, and on-site training. LESSONS LEARNT: While widely practiced throughout the world, M&Ms typically do not involve both clinical and non-clinical staff members and do not take a systems-level approach. The authors' experience suggests that the adapted M&M conference is a simple, feasible tool for quality improvement in resource-limited settings. Senior managerial commitment is crucial to ensure successful implementation of M&Ms, given the challenging logistics of implementing these programmes in resource-limited health facilities.