Veterinary use and antibiotic resistance

Author: Teuber, M. Description: Globally, an estimated 50% of all antimicrobials serve veterinary purposes. Bacteria that inevitably develop antibiotic resistance in animals comprise food-borne pathogens, opportunistic pathogens and commensal bacteria. The same antibiotic resistance genes and gene transfer mechanisms can be found in the microfloras of animals and humans. Direct contact, food and water link animal and human habitats. The accumulation of resistant bacteria by the use of antibiotics in agriculture and veterinary medicine and the spread of such bacteria via agriculture and direct contamination are documented. Subject headings: Agriculture;…

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Long-term application of fresh and composted manure increase tetracycline resistance in the arable soil of eastern China

Author: Peng, S.; Wang, Y.; Zhou, B.; Lin, X. Description: The aim of this study was to compare the occurrence, abundance, and diversity of tetracycline resistance genes (tet) in agricultural soils after 6 years’ application of fresh or composted swine manure. Soil samples were collected from fresh or composted manure-treated farmland at three depths (0-5 cm, 5-10 cm, and 10-20 cm). Nine classes of tet genes [tetW, tetB(P), tetO, tetS, tetC, tetG, tetZ, tetL, and tetX] were detected; tetG, tetZ, tetL, and tetB(P) were predominant in the manure-treated soil. The…

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Detection of hepatitis E virus and other livestock-related pathogens in Iowa streams

Author: Givens, C.E.; Kolpin, D.W.; Borchardt, M.A.; Duris, J.W.; Moorman, T.B.; Spencer, S.K. Description: Manure application is a source of pathogens to the environment. Through overland runoff and tile drainage, zoonotic pathogens can contaminate surface water and streambed sediment and could affect both wildlife and human health. This study examined the environmental occurrence of gene markers for livestock-related bacterial, protozoan, and viral pathogens and antibiotic resistance in surface waters within the South Fork Iowa River basin before and after periods of swine manure application on agricultural land. Increased concentrations of…

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Virulence factors in brucellosis: implications for aetiopathogenesis and treatment

Author: Fugier, E.; Pappas, G.; Gorvel, J.-P. Description: Brucella species are responsible for the global zoonotic disease brucellosis. These intracellular pathogens express a set of factors – including lipopolysaccharides, virulence regulator proteins and phosphatidylcholine – to ensure their full virulence. Some virulence factors are essential for invasion of the host cell, whereas others are crucial to avoid elimination by the host. They allow Brucella spp. to survive and proliferate within its replicative vacuole and enable the bacteria to escape detection by the host immune system. Several strategies have been used…

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Antibiotics, microbiota, and immune defense

Author: Ubeda, C.; Pamer, E.G. Description: The gastrointestinal tract microbiota contributes to the development and differentiation of the mammalian immune system. The composition of the microbiota affects immune responses and affects susceptibility to infection by intestinal pathogens and development of allergic and inflammatory bowel diseases. Antibiotic administration, while facilitating clearance of targeted infections, also perturbs commensal microbial communities and decreases host resistance to antibiotic-resistant microbes. Here, we review recent advances that begin to define the interactions between complex intestinal microbial populations and the mammalian immune system and how this relation…

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A hospital outbreak of Serratia marcescens associated with ultrasonic nebulizers

Ringrose, R.E., McKown, B., Felton, F.G., Barclay, B.O., Muchmore, H.G., Rhoades, E.R. (1968) Annals of Internal Medicine, 69(4), 719-729 A sevenfold increase in the frequency of isolation of Serratia marcescens was noted during a 2-month period. Nineteen patients were involved, and the majority of these patients acquired the organism during hospitalization. Two of the patients had signs and symptoms of definite infection. Seven others probably had infections, and the remainder appeared to have had simple colonization. All 19 patients had associated medical conditions or prior therapy. S. marcescens should be…

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A Bacterial Pathogen Targets a Host Rab-Family GTPase Defense Pathway with a GAP

Author: Spano, Stefania; Gao, Xiang; Hannemann, Sebastian; Lara-Tejero, Mari­a; Galan, Jorge E. Description: Cell-autonomous defense mechanisms are potent strategies that protect individual cells against intracellular pathogens. The Rab-family GTPase Rab32 was previously shown to restrict the intracellular human pathogen Salmonella Typhi, but its potential broader role in antimicrobial defense remains unknown. We show that Rab32 represents a general cell-autonomous, antimicrobial defense that is counteracted by two Salmonella effectors. Mice lacking Rab-32 or its nucleotide exchange factor BLOC-3 are permissive to S. Typhi infection and exhibit increased susceptibility to S. Typhimurium….

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Morphological plasticity as a bacterial survival strategy

Author: Justice, S.S.; Hunstad, D.A.; Cegelski, L.; Hultgren, S.J. Description: Bacteria have evolved complex systems to maintain consistent cell morphologies. Nevertheless, in certain circumstances, bacteria alter this highly regulated process to transform into filamentous organisms. Accumulating evidence attributes important biological roles to filamentation in stressful environments, including, but not limited to, sites of interaction between pathogenic bacteria and their hosts. Filamentation could represent an intended response to specific environmental cues that promote survival amidst the threats of consumption and killing. Subject headings: Adaptation, Physiological; Animals; Epithelial Cells/microbiology; Escherichia coli/pathogenicity/physiology; Gram-Negative…

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A comprehensive review of the antibacterial, antifungal and antiviral potential of essential oils and their chemical constituents against drug-resistant microbial pathogens

Author: Tariq, Saika; Wani, Saira; Rasool, Waseem; Shafi, Khushboo; Bhat, Muzzaffar Ahmad; Prabhakar, Anil; Shalla, Aabid Hussain; Rather, Manzoor A. Description: Essential oils are a complex mixture of odoriferous, volatile organic compounds. There are an extensive number of published articles which highlight the antimicrobial action of a variety of essential oils from various parts of the world. The main aim of this review article is to compile these antimicrobial essential oils and their constituents from reliable sources and put them together. The published literature indicates that essential oils possess a…

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Co-selection of multi-antibiotic resistance in bacterial pathogens in metal and microplastic contaminated environments: An emerging health threat

Author: Imran, Md; Das, Kirti Ranjan; Naik, Milind Mohan Description: Misuse/over use of antibiotics increases the threats to human health since this is a main reason behind evolution of antibiotic resistant bacterial pathogens. However, metals such as mercury, lead, zinc, copper and cadmium are accumulating to critical concentration in the environment and triggering co-selection of antibiotic resistance in bacteria. The co-selection of metal driven antibiotic resistance in bacteria is achieved through co-resistance or cross resistance. Metal driven antibiotic resistant determinants evolved in bacteria and present on same mobile genetic elements…

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