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1.
Support Care Cancer ; 32(7): 438, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38880860

RESUMO

PURPOSE: There are limited treatment options available for hematopoietic stem-cell transplant patients (HSCT) with oral graft-versus-host disease (GVHD). Intraoral phototherapy is a novel, yet promising therapeutic regimen. RESEARCH QUESTION: To assess the safety and effectiveness of intraoral narrowband UVB (nbUVB) phototherapy in the treatment of oral GVHD. METHODS: This case series evaluated 10 patients with refractory oral GVHD, who were treated at Northwestern Memorial Hospital with nbUVB between July 2019 and October 2023. Primary outcomes were to evaluate the safety and efficacy of phototherapy. Efficacy was measured by objective improvement in symptom scores and subjective improvement in patient reported symptoms. Safety was determined by the withdrawal due to adverse events. Total nbUVB exposure, number of treatments, and change in systemic immunosuppressive medications were also examined. RESULTS: The study cohort comprised 10 patients who developed oral GVHD at a median of 9.5 months after HSCT. The total median dose of nbUVB was 36 J/cm2, and the median number of sessions was 55. All 10 patients demonstrated some degree of improvement in symptoms. Notably, there was a reduction in the number of patients who reported symptoms of oral pain (83%), bleeding (67%), xerostomia (50%), and oral sensitivity (78%) after initiating phototherapy. There was also a statistically significant decrease in the levels of pain, erythema, and edema (p ≤ 0.001, < 0.001, 0.01, respectively). Most patients tolerated phototherapy well, but 1 patient withdrew from treatment due to adverse effects. Seventy-five percent of patients who were on immunosuppressive medications were able to decrease or stop these medications. CONCLUSION: This case series suggests that nbUVB phototherapy is well tolerated and efficacious in patients with oral GVHD.


Assuntos
Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Doenças da Boca , Terapia Ultravioleta , Humanos , Doença Enxerto-Hospedeiro/radioterapia , Doença Enxerto-Hospedeiro/terapia , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Transplante de Células-Tronco Hematopoéticas/métodos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Terapia Ultravioleta/métodos , Terapia Ultravioleta/efeitos adversos , Doenças da Boca/terapia , Doenças da Boca/etiologia , Idoso , Estudos Retrospectivos
2.
Chemphyschem ; 24(23): e202300062, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37679310

RESUMO

Surfactants are used to control the macroscopic properties of the air-water interface. However, the link between the surfactant molecular structure and the macroscopic properties remains unclear. Using sum-frequency generation spectroscopy and molecular dynamics simulations, two ionic surfactants (dodecyl trimethylammonium bromide, DTAB, and sodium dodecyl sulphate, SDS) with the same carbon chain lengths and charge magnitude (but different signs) of head groups interact and reorient interfacial water molecules differently. DTAB forms a thicker but sparser interfacial layer than SDS. It is due to the deep penetration into the adsorption zone of Br- counterions compared to smaller Na+ ones, and also due to the flip-flop orientation of water molecules. SDS alters two distinctive interfacial water layers into a layer where H+ points to the air, forming strong hydrogen bonding with the sulphate headgroup. In contrast, only weaker dipole-dipole interactions with the DTAB headgroup are formed as they reorient water molecules with H+ point down to the aqueous phase. Hence, with more molecules adsorbed at the interface, SDS builds up a higher interfacial pressure than DTAB, producing lower surface tension and higher foam stability at a similar bulk concentration. Our findings offer improved knowledge for understanding various processes in the industry and nature.

3.
Am J Dermatopathol ; 45(9): 654-657, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37625804

RESUMO

ABSTRACT: Giant cell arteritis (GCA) is a diagnosis that clinicians should not miss because of the accompanying risk of irreversible vision loss. GCA can present without the classic symptoms of headache and temporal artery tenderness, which may lead to a delay in diagnosis. Cutaneous findings, although rare, have been associated with GCA. Accordingly, it is imperative to be aware of the broad clinical and histological presentations of GCA, including the cutaneous findings, because they may prove to be harbingers of impending disease. We present a unique case of GCA where 2 distinct cutaneous morphologies, sarcoidal granuloma annulare-like dermatitis and leukocytoclastic vasculitis with granulomatous features, presented simultaneously before the classic symptoms of headache and unilateral vision loss.


Assuntos
Dermatite , Arterite de Células Gigantes , Granuloma Anular , Vasculite Leucocitoclástica Cutânea , Humanos , Arterite de Células Gigantes/complicações , Arterite de Células Gigantes/diagnóstico , Granuloma Anular/diagnóstico , Vasculite Leucocitoclástica Cutânea/diagnóstico , Vasculite Leucocitoclástica Cutânea/tratamento farmacológico , Vasculite Leucocitoclástica Cutânea/etiologia , Cefaleia
4.
J Environ Manage ; 344: 118488, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37393870

RESUMO

Mineral tailings dams pose high pollution risks to the environment and catastrophic failures. Dry stacking has been identified as a promising alternative to mitigate these risks and offers various benefits to the mining industry but lacks systematic research outcomes. To facilitate dry stacking, coal tailings slurries were dewatered using either filtration or centrifugation methods, resulting in a semi-solid form (cake) that can be safely disposed of. The handleability and disposability of these cakes are greatly influenced by the selection of chemical aids (such as polymer flocculants) and the mechanical dewatering technique employed. The effects of polyacrylamide (PAM) flocculants with a range of molecular weight, charge, and charge density are presented. Coal tailings samples with differences in clay mineralogy were dewatered using press filtration, solid bowl centrifugation, and natural air drying. Handleability and disposability of the tailings were assessed by their rheological properties, including yield stress, adhesive and cohesive stresses, and stickiness. Residue moisture, type of polymer flocculants, and clay mineralogy were found to be crucial factors affecting the handleability and disposability of the dewatered cakes. The tailing yield stress (shear strength) increased as the solid concentration increased. In the semi-solid regime (above 60 wt% solids), the tailings displayed stiff exponential growth. Similar trends were observed for stickiness and adhesive/cohesive energy of the tailings with a steel (truck) surface. Adding polymer flocculants increased the shear strength of the dewatered tailings by 10-15%, thus favouring disposability. However, the polymer selection for coal tailing handling and processing is a trade-off between its disposability and handleability, which requires a multi-criteria decision-making process. The current results also suggested that cationic PAM could be most suitable for dewatering by press filtration, while anionic PAM should be selected for dewatering by solid bowl centrifugation.


Assuntos
Carvão Mineral , Polímeros , Argila , Resistência ao Cisalhamento , Poluição Ambiental
5.
Molecules ; 28(9)2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37175380

RESUMO

Solvent extraction has been ubiquitously used to recover valuable metals from wastes such as spent batteries and electrical boards. With increasing demands for energy transition, there is a critical need to improve the recycling rate of critical metals, including copper. Therefore, the sustainability of reagents is critical for the overall sustainability of the process. Yet, the recycling process relies on functional organic compounds based on the hydroxyoxime group. To date, hydroxyoxime extractants have been produced from petrol-based chemical feedstocks. Recently, natural-based cardanol has been used to produce an alternative hydroxyoxime. The natural-based oxime has been employed to recover valuable metals (Ga, Ni, Co) via a liquid/liquid extraction process. The natural compound has a distinctive structure with 15 carbons in the alkyl tail. In contrast, petrol-based hydroxyoximes have only 12 or fewer carbons. However, the molecular advantages of this natural-based compound over the current petrol-based ones remain unclear. In this study, molecular dynamics simulation was employed to investigate the effect of extractant hydrocarbon chains on the extraction of copper ions. Two hydroxyoxime extractants with 12 and 15 carbons in the alkyl chain were found to have similar interactions with Cu2+ ions. Yet, a slight molecular binding increase was observed when the carbon chain was increased. In addition, lengthening the carbon chain made the extracting stage easier and the stripping stage harder. The binding would result in a lower pH in the extraction step and a lower pH in the stripping step. The insights from this molecular study would help design the extraction circuit using natural-based hydroxyoxime extractants. A successful application of cashew-based cardanol will improve the environmental benefits of the recycling process. With cashew-producing regions in developing countries, the application also improves these regions' social and economic sustainability.

6.
J Am Acad Dermatol ; 87(6): 1278-1280, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36075281

RESUMO

The World Health Organization declared the global monkeypox outbreak a public health emergency of international concern in July 2022. In response, the American Academy of Dermatology and International League of Dermatological Societies expanded the existing COVID-19 Dermatology Registry to become the "AAD/ILDS Dermatology COVID-19, Monkeypox, and Emerging Infections Registry." The goal of the registry is to rapidly collate cases of monkeypox and other emerging infections and enable prompt dissemination of findings to front-line healthcare workers and other members of the medical community. The registry is now accepting reports of monkeypox cases and cutaneous reactions to monkeypox/smallpox vaccines. The success of this collaborative effort will depend on active case entry by the global dermatology community.


Assuntos
COVID-19 , Dermatologia , Mpox , Estados Unidos/epidemiologia , Humanos , COVID-19/epidemiologia , Sociedades Médicas , Sistema de Registros
7.
Am J Dermatopathol ; 44(11): 812-816, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-35925148

RESUMO

ABSTRACT: Cutaneous ganglioneuromas (GNs) are exceptionally uncommon tumors, and many reported cases describe association with overlying epidermal hyperplasia that may be interpreted as seborrheic keratosis (SK) or SK-like proliferation. We report 5 cases of cutaneous GN in adult patients; all of which were discovered incidentally in the immediate vicinity of epidermal hyperplasia. A review of the literature demonstrates the current-although likely imperfect-understanding of the etiopathogenesis of both SK and GN in the skin. We explore the putative pathophysiologies of other common, well-characterized skin lesions and, taking them into account, provide rationale for the coexistence of cutaneous GN with overlying SK and SK-like epidermal changes. However, we ultimately acknowledge a dilemma of causality and, given the rarity of their co-occurrence, objectively question whether occasional cameo appearances by GN lying subjacent to SK and SK-like hyperplasia may be due merely to chance.


Assuntos
Ganglioneuroma , Ceratose Seborreica , Dermatopatias , Neoplasias Cutâneas , Adulto , Ganglioneuroma/complicações , Humanos , Hiperplasia , Ceratose Seborreica/patologia , Neoplasias Cutâneas/complicações , Neoplasias Cutâneas/patologia
8.
Langmuir ; 37(7): 2237-2255, 2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33559472

RESUMO

Surfactants are centrally important in many scientific and engineering fields and are used for many purposes such as foaming agents and detergents. However, many challenges remain in providing a comprehensive understanding of their behavior. Here, we provide a brief historical overview of the study of surfactant adsorption at the air-water interface, followed by a discussion of some recent advances in this area from our group. The main focus is on incorporating an accurate description of the adsorption layer thickness of surfactant at the air-water interface. Surfactants have a wide distribution at the air-water interface, which can have a significant effect on important properties such as the surface excess, surface tension, and surface potential. We have developed a modified Poisson-Boltzmann (MPB) model to describe this effect, which we outline here. We also address the remaining challenges and future research directions in this area. We believe that experimental techniques, modeling, and simulation should be combined to form a holistic picture of surfactant adsorption at the air-water interface.

9.
J Cutan Pathol ; 48(3): 390-395, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33063358

RESUMO

Basal cell nevus syndrome (BCNS) is an autosomal dominant condition caused most often by a loss-of-function mutation in the Patched-1 (PTCH1) gene. It is characterized by the development of varied benign and malignant tumors, including numerous cutaneous basal cell carcinomas (BCCs). The PTCH1 gene is integral in hair follicle development and loss of function mutation may lead to BCCs with an infundibulocystic histopathology in BCNS patients. Few studies have described the histopathological features of BCCs in BCNS. The recognition of these histopathologic features by dermatologists, dermatopathologists, and others caring for children will allow earlier and more effective identification of BCNS. We performed a retrospective analysis of 25 BCCs in 11 patients aged 5 to 19 years with BCNS and evaluated the histopathologic features on hematoxylin-eosin-stained sections. Our study found that 80% of BCCs in BCNS patients occurred on the head and neck with 64% of the specimens demonstrating infundibulocystic differentiation. Infundibulocystic differentiation is a common finding in BCCs found in BCNS. The finding of cutaneous neoplasms consistent with BCC with infundibulocystic differentiation in children is common in pediatric patients with BCNS and can be considered to be an early marker of the disorder, prompting further clinical investigation.


Assuntos
Síndrome do Nevo Basocelular/complicações , Carcinoma Basocelular/diagnóstico , Neoplasias Cutâneas/patologia , Adolescente , Síndrome do Nevo Basocelular/genética , Carcinoma Basocelular/genética , Carcinoma Basocelular/patologia , Diferenciação Celular/genética , Criança , Pré-Escolar , Diagnóstico Precoce , Feminino , Humanos , Masculino , Receptor Patched-1/genética , Estudos Retrospectivos , Adulto Jovem
10.
Skeletal Radiol ; 50(9): 1763-1773, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33598718

RESUMO

The global pandemic of coronavirus disease 2019 (COVID-19) has revealed a surprising number of extra-pulmonary manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. While myalgia is a common clinical feature of COVID-19, other musculoskeletal manifestations of COVID-19 were infrequently described early during the pandemic. There have been emerging reports, however, of an array of neuromuscular and rheumatologic complications related to COVID-19 infection and disease course including myositis, neuropathy, arthropathy, and soft tissue abnormalities. Multimodality imaging supports diagnosis and evaluation of musculoskeletal disorders in COVID-19 patients. This article aims to provide a first comprehensive summary of musculoskeletal manifestations of COVID-19 with review of imaging.


Assuntos
COVID-19 , Doenças do Sistema Nervoso Periférico , Humanos , Pulmão , Pandemias , SARS-CoV-2
11.
J Cutan Pathol ; 47(3): 286-290, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31605494

RESUMO

Sclerotic lipomas, a lipoma variant, are benign subcutaneous tumors, so-named because of their resemblance to sclerotic fibromas. Previous literature has suggested that these tumors may show a predilection for middle-aged adult males. We report an unusual case of a sclerotic lipoma diagnosed on the scalp of a 66-year-old female. The patient presented to the outpatient clinic with a 3- to 4-year history of an enlarging and irritated 2.6-cm nodule on the anterior crown of the scalp, clinically thought to be a pilar cyst. Histopathological examination from the excisional specimen revealed a well-circumscribed dermal to subcutaneous tumor with ample sclerotic collagen bundles, an increased number of CD34 positive spindled cells, and prominent S-100 positive mature adipocytes comprising greater than 50% of the tumor. We present this case given its atypical clinical and histopathological presentation, review the literature of sclerotic lipomas, and discuss the differential diagnosis to raise awareness of this rare entity.


Assuntos
Neoplasias de Cabeça e Pescoço/patologia , Lipoma/patologia , Couro Cabeludo/patologia , Neoplasias Cutâneas/patologia , Idoso , Feminino , Humanos , Esclerose/patologia
12.
Pediatr Dermatol ; 37(2): 305-310, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31957924

RESUMO

BACKGROUND/OBJECTIVE: Tinea capitis is a common infection of scalp hair in children. The prevalent etiologic organism has changed significantly over time, which may reflect the complex interaction of environmental factors, genetic predisposition, and movement of populations. We evaluate the prevalence of different infectious organisms causing tinea capitis and describe the clinical characteristics. METHODS: A retrospective chart review of patients diagnosed with tinea capitis with tissue culture confirmation, who were seen in pediatric dermatology at a tertiary care center from 2010 to 2015. Patient demographics, culture data, and clinical characteristics were evaluated. Inflammatory pattern, characterized by presence of pustules, bogginess, or lymphadenopathy, was noted. RESULTS: Forty-six patients with culture-positive tinea capitis were identified. In the 18 (42.9%) patients who were infected with either Trichophyton violaceum or Trichophyton soudanenese, all were of African ethnicity. In contrast, Trichophyton tonsurans was identified in a minority of African patients (3.8%), revealing a statistically significant difference between ethnicity and infective species (P-value < 0.001). T tonsurans was significantly more likely than T violaceum to exhibit an inflammatory pattern (68% vs 22%, P value < 0.027). CONCLUSIONS: While T tonsurans remained the most common cause of tinea capitis, T violaceum and T soudanense have increased in prevalence. As these latter agents are less inflammatory, clinical diagnosis may be delayed. Studying changes in the infectious cause of tinea capitis can help us create a snapshot to better understand the evolution of our population make-up, allowing us to provide crucial quality health care to all.


Assuntos
Tinha do Couro Cabeludo/microbiologia , Tinha do Couro Cabeludo/patologia , Adolescente , Arthrodermataceae , Criança , Pré-Escolar , Estudos Transversais , Etnicidade/estatística & dados numéricos , Feminino , Humanos , Lactente , Masculino , Estudos Retrospectivos , Tinha do Couro Cabeludo/etnologia
13.
Theor Popul Biol ; 126: 33-39, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30641072

RESUMO

We consider the ancestral state reconstruction problem where we need to infer phenotypes of ancestors using observations from present-day species. For this problem, we propose a multi-task learning method that uses regularized maximum likelihood to estimate the ancestral states of various traits simultaneously. We then show both theoretically and by simulation that this method improves the estimates of the ancestral states compared to the maximum likelihood method. The result also indicates that for the problem of ancestral state reconstruction under the Brownian motion model, the maximum likelihood method can be improved.


Assuntos
Funções Verossimilhança , Aprendizado de Máquina , Modelos Biológicos , Fenótipo , Animais , Evolução Biológica , Simulação por Computador , Humanos , Aprendizagem , Mamíferos , Filogenia , Processos Estocásticos
16.
Plant Cell ; 26(2): 585-601, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24510723

RESUMO

Fruit ripening is the summation of changes rendering fleshy fruit tissues attractive and palatable to seed dispersing organisms. For example, sugar content is influenced by plastid numbers and photosynthetic activity in unripe fruit and later by starch and sugar catabolism during ripening. Tomato fruit are sinks of photosynthate, yet unripe green fruit contribute significantly to the sugars that ultimately accumulate in the ripe fruit. Plastid numbers and chlorophyll content are influenced by numerous environmental and genetic factors and are positively correlated with photosynthesis and photosynthate accumulation. GOLDEN2-LIKE (GLK) transcription factors regulate plastid and chlorophyll levels. Tomato (Solanum lycopersicum), like most plants, contains two GLKs (i.e., GLK1 and GLK2/UNIFORM). Mutant and transgene analysis demonstrated that these genes encode functionally similar peptides, though differential expression renders GLK1 more important in leaves, while GLK2 is predominant in fruit. A latitudinal gradient of GLK2 expression influences the typical uneven coloration of green and ripe wild-type fruit. Transcriptome profiling revealed a broader fruit gene expression gradient throughout development. The gradient influenced general ripening activities beyond plastid development and was consistent with the easily observed yet poorly studied ripening gradient present in tomato and many fleshy fruits.


Assuntos
Frutas/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Solanum lycopersicum/crescimento & desenvolvimento , Fatores de Transcrição/metabolismo , Carotenoides/metabolismo , Clorofila/metabolismo , Cloroplastos/metabolismo , Cloroplastos/ultraestrutura , Etilenos/metabolismo , Frutas/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Histonas/metabolismo , Solanum lycopersicum/genética , Lisina/metabolismo , Metilação , Mutação/genética , Especificidade de Órgãos/genética , Fenótipo , Fotossíntese/genética , Folhas de Planta/anatomia & histologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Fatores de Transcrição/genética
17.
J Cutan Pathol ; 44(2): 177-182, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27862184

RESUMO

The diagnosis of serum sickness-like reaction (SSLR) is typically based on clinical findings. Histopathologic examination is often deferred, as these eruptions commonly present in young children, and often to primary care providers. A PubMed literature search revealed only five existing cases of SSLR which describe cutaneous histopathologic features. We report two cases of SSLR, one each to bupropion and cefazolin. Skin biopsy findings in both cases showed a neutrophil-predominant urticarial pattern resembling neutrophilic urticaria or neutrophilic urticarial dermatosis. We also provide a summary of the histopathologic findings that can help support a diagnosis of SSLR.


Assuntos
Toxidermias/patologia , Neutrófilos/patologia , Doença do Soro/patologia , Urticária/induzido quimicamente , Urticária/patologia , Idoso , Antibacterianos/efeitos adversos , Antidepressivos de Segunda Geração/efeitos adversos , Bupropiona/efeitos adversos , Cefazolina/efeitos adversos , Humanos , Masculino , Adulto Jovem
18.
Pediatr Dermatol ; 34(1): e65-e68, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27874201

RESUMO

The follicular presentation of psoriasis is a well-described but uncommon variant. In some cases, follicular psoriasis may clinically and histopathologically mimic pityriasis rubra pilaris. There are several reports discussing the resemblance of widespread follicular psoriasis in children to pityriasis rubra pilaris. We describe a case of follicular psoriasis in a 16-year-old black girl with acrally distributed follicular hyperkeratotic papules with associated keratoderma of her plantar surfaces resembling pityriasis rubra pilaris.


Assuntos
Pitiríase Rubra Pilar/diagnóstico , Psoríase/diagnóstico , Pele/patologia , Adolescente , Diagnóstico Diferencial , Feminino , Humanos
19.
Semin Cutan Med Surg ; 36(1): 17-22, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28247871

RESUMO

Skin biopsy remains one of the most important tools in the evaluation of dermatologic disease in hospitalized patients and is diagnostic for many common inpatient dermatoses, including various drug eruptions and cutaneous infections. The dermatopathology team thus plays a crucial role in the care of many of these patients and can add significant value through timely and precise diagnoses. Here, we review the unique challenges of dermatopathology in hospital-based medicine, discuss approaches to timely care, and examine effective clinicopathologic correlation in this setting.


Assuntos
Biópsia , Dermatologia , Medicina Hospitalar , Dermatopatias/diagnóstico , Dermatopatias/patologia , Pele/patologia , Biópsia/métodos , Humanos , Dermatopatias Infecciosas/microbiologia , Dermatopatias Infecciosas/patologia , Manejo de Espécimes
20.
Appl Environ Microbiol ; 82(13): 3727-3735, 2016 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-27084016

RESUMO

UNLABELLED: Antimicrobial resistance (AMR) is a global health problem, and emerging semi-intensive farming systems in Southeast Asia are major contributors to the AMR burden. We accessed 12 pig and chicken farms at key stages of production in Tien Giang Province, Vietnam, to measure antimicrobial usage and to investigate the prevalence of AMR to five critical antimicrobials (ß-lactams, third-generation cephalosporins, quinolones, aminoglycosides, and polymyxins) and their corresponding molecular mechanisms among 180 Escherichia coli isolates. Overall, 94.7 mg (interquartile range [IQR], 65.3 to 151.1) and 563.6 mg (IQR, 398.9 to 943.6) of antimicrobials was used to produce 1 kg (live weight) of chicken and pig, respectively. A median of 3 (out of 8) critical antimicrobials were used on pig farms. E. coli isolates exhibited a high prevalence of resistance to ampicillin (97.8% and 94.4% for chickens and pigs, respectively), ciprofloxacin (73.3% and 21.1%), gentamicin (42.2% and 35.6%), and colistin (22.2% and 24.4%). The prevalence of a recently discovered colistin resistance gene, mcr-1, was 19 to 22% and had strong agreement with phenotypic colistin resistance. We conducted plasmid conjugation experiments with 37 mcr-1 gene-positive E. coli isolates and successfully observed transfer of the gene in 54.0% of isolates through a plasmid of approximately 63 kb, consistent with one recently identified in China. We found no significant correlation between total use of antimicrobials at the farm level and AMR. These data provide additional insight into the role of mcr-1 in colistin resistance on farms and outline the dynamics of phenotypic and genotypic AMR in semi-intensive farming systems in Vietnam. IMPORTANCE: Our study provides accurate baseline information on levels of antimicrobial use, as well as on the dynamics of phenotypic and genotypic resistance for antimicrobials of critical importance among E. coli over the different stages of production in emerging pig and poultry production systems in Vietnam. E. coli isolates showed a high prevalence of resistance (>20%) to critically important antimicrobials, such as colistin, ciprofloxacin, and gentamicin. The underlying genetic mechanisms identified for colistin (the mcr-1 gene) and quinolone (gyrA gene mutations) are likely to play a major role in AMR to those compounds. Conjugation experiments led to the identification of a 63-kb plasmid, similar to one recently identified in China, as the potential carrier of the mcr-1 gene. These results should encourage greater restrictions of such antimicrobials in Southeast Asian farming systems.


Assuntos
Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Colistina/farmacologia , Colistina/uso terapêutico , Farmacorresistência Bacteriana , Infecções por Escherichia coli/veterinária , Escherichia coli/efeitos dos fármacos , Animais , Galinhas , Conjugação Genética , Uso de Medicamentos , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/microbiologia , Fazendas , Transferência Genética Horizontal , Plasmídeos/análise , Suínos , Vietnã
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