pesticides residue poses serious concerns to human health. the present study was carried out to determine the pesticide residues of peri-urban bovine milk (n = 1183) from five different sites (Bangalore, Bhubaneswar, Guwahati, Ludhiana and Udaipur) in India and dietary exposure risk assessment to adults and children. pesticide residues were estimated using gas chromatography with flame thermionic and electron capture detectors followed by confirmation on gas chromatographymass spectrometer. The results noticed the contamination of milk with hexachlorocyclohexane (HCH), dichloro-diphenyl trichloroethane (DDT), endosulfan, cypermethrin, cyhalothrin, permethrin, chlorpyrifos, ethion and profenophos pesticides. the residue levels in some of the milk samples were observed to be higher than the respective maximum residue limits (MRLs) for pesticide. Milk samples contamination was found highest in Bhubaneswar (11.2%) followed by Bangalore (9.3%), Ludhiana (6.9%), Udaipur (6.4%) and Guwahati (6.3%). The dietary risk assessment of pesticides under two scenarios i.e. lower-bound scenario (LB) and upper-bound (UB) revealed that daily intake of pesticides was substantially below the prescribed acceptable daily intake except for fipronil in children at UB. The non-cancer risk by estimation of hazard index (HI) was found to be below the target value of one in adults at all five sites in India. However, for children at the UB level, the HI for lindane, DDT and ethion exceeded the value of one in Ludhiana and Udaipur. Cancer risk for adults was found to be in the recommended range of United States environment protection agency (USEPA), while it exceeded the USepA values for children.
Inappropriate and disproportionate use of antibiotics is contributing immensely to the development of antibiotic resistance in bacterial species associated with food contamination. The use of natural products in combination can be a potent alternative hurdle strategy to inactivate foodborne pathogens. Here, we explored the pro-oxidant properties of essential oil linalool and vitamin C in combination with copper (LVC) in combating the foodborne pathogens Vibrio fluvialis and Salmonella enterica subsp. enterica serovar Typhi using a three-dimensional (3D) checkerboard microdilution assay. Antibacterial activity in terms of the MIC revealed that the triple combination exerted a synergistic effect compared to the effects of the individual constituents. The bactericidal effect of the triple combination was confirmed by a live/dead staining assay. Reactive oxygen species (ROS) measurements with the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling assay and scanning electron microscopy imaging strongly suggested that the increase in ROS production is the underlying mechanism of the enhanced antibacterial potency of the LVC combination (linalool [1.298 mM], vitamin C [8 mM], copper [16.3 μM]). In addition, the hypersensitivity of oxidative stress regulator mutants (oxyR, katG, ahpC, and sodA mutants) toward LVC corroborated the involvement of ROS in cell death. Live/dead staining and changes in cellular morphology revealed that oxidative stress did not transform the cells into the viable but nonculturable (VBNC) state; rather, killing was associated with intracellular and extracellular oxidative burst. Furthermore, the LVC combination did not display toxicity to human cells, while it effectively reduced the pathogen levels in acidic fruit juices by 3 to 4 log CFU/ml without adversely altering the organoleptic properties. This study opens a new outlook for combinatorial antimicrobial therapy. IMPORTANCE There is a need to develop effective antibacterial therapies for mitigating bacterial pathogens in food systems. We used a 3D checkerboard assay to ascertain a safe synergistic combination of food-grade components: vitamin C, copper, and the essential oil linalool. Individually, these constituents have to be added in large amounts to exert their antibacterial effect, which leads to unwanted organoleptic properties. The triple combination could exceptionally inhibit foodborne Gram-negative pathogens like Vibrio fluvialis and Salmonella enterica subsp. enterica serovar Typhi at low concentrations (linalool, 1.298 mM; vitamin C, 8 mM; copper, 16.3 μM) and displayed potent microbial inhibition in acidic beverages. We found increased susceptibility in deletion mutants of oxidative stress regulators (oxyR, katG, ahpC, and sodA mutants) due to ROS generation by Fenton’s chemistry. The results of this study show that it may be possible to use plant-based antimicrobials in synergistic combinations to control microbial contaminants.
Background: Tetracycline antibiotics are widely used for prevention and control of disease. However, the presence of tetracycline antibiotics residues in food is a serious public health concern because of the harmful effects of these residues on consumer's health. Therefore, it is necessary to detect tetracycline residues in food of animal origin keeping in view the food safety issues and problem related to antibiotic resistance. Aim:To investigate and monitor the occurrence of tetracycline residues in cattle milk in five districts of Punjab. Materials and Methods:In this study, a total of 133 cattle milk samples were collected from dairies of 5 districts of Punjab state, India in May, 2013 and were tested and analyzed for their contamination status with tetracycline residues.Results: Out of these 133 milk samples analyzed, 18 samples were found to contain tetracycline residues. The percentages of tetracycline detected in the samples from 5 districts were in the range of 0-46.15%. The concentration of tetracycline residues in cattle milk samples were found to be in the range 16-134.5 ppb. Conclusions:Three samples exceeded the maximum recommended tetracycline antibiotic residue levels (MRLs) as prescribed by the European Union and the Codex Alimentarius Commission .
The increasing prevalence of antimicrobial resistance has become a global health problem. Acinetobacter baumannii is an important nosocomial pathogen due to its capacity to persist in the hospital environment. It has a high mortality rate and few treatment options. Antibiotic combinations can help to fight multi-drug resistant (MDR) bacterial infections, but they are rarely used in the clinics and mostly unexplored. The interaction between bacteriostatic and bactericidal antibiotics are mostly reported as antagonism based on the results obtained in the susceptible model laboratory strain Escherichia coli. However, in the present study, we report a synergistic interaction between nalidixic acid and tetracycline against clinical multi-drug resistant A. baumannii and E. coli. Here we provide mechanistic insight into this dichotomy. The synergistic combination was studied by checkerboard assay and time-kill curve analysis. We also elucidate the mechanism behind this synergy using several techniques such as fluorescence spectroscopy, flow cytometry, fluorescence microscopy, morphometric analysis, and real-time polymerase chain reaction. Nalidixic acid and tetracycline combination displayed synergy against most of the MDR clinical isolates of A. baumannii and E. coli but not against susceptible isolates. Finally, we demonstrate that this combination is also effective in vivo in an A. baumannii/Caenorhabditis elegans infection model (p < 0.001)
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