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1.
N Engl J Med ; 382(10): 893-902, 2020 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-32130813

RESUMEN

BACKGROUND: Patients with highly drug-resistant forms of tuberculosis have limited treatment options and historically have had poor outcomes. METHODS: In an open-label, single-group study in which follow-up is ongoing at three South African sites, we investigated treatment with three oral drugs - bedaquiline, pretomanid, and linezolid - that have bactericidal activity against tuberculosis and to which there is little preexisting resistance. We evaluated the safety and efficacy of the drug combination for 26 weeks in patients with extensively drug-resistant tuberculosis and patients with multidrug-resistant tuberculosis that was not responsive to treatment or for which a second-line regimen had been discontinued because of side effects. The primary end point was the incidence of an unfavorable outcome, defined as treatment failure (bacteriologic or clinical) or relapse during follow-up, which continued until 6 months after the end of treatment. Patients were classified as having a favorable outcome at 6 months if they had resolution of clinical disease, a negative culture status, and had not already been classified as having had an unfavorable outcome. Other efficacy end points and safety were also evaluated. RESULTS: A total of 109 patients were enrolled in the study and were included in the evaluation of efficacy and safety end points. At 6 months after the end of treatment in the intention-to-treat analysis, 11 patients (10%) had an unfavorable outcome and 98 patients (90%; 95% confidence interval, 83 to 95) had a favorable outcome. The 11 unfavorable outcomes were 7 deaths (6 during treatment and 1 from an unknown cause during follow-up), 1 withdrawal of consent during treatment, 2 relapses during follow-up, and 1 loss to follow-up. The expected linezolid toxic effects of peripheral neuropathy (occurring in 81% of patients) and myelosuppression (48%), although common, were manageable, often leading to dose reductions or interruptions in treatment with linezolid. CONCLUSIONS: The combination of bedaquiline, pretomanid, and linezolid led to a favorable outcome at 6 months after the end of therapy in a high percentage of patients with highly drug-resistant forms of tuberculosis; some associated toxic effects were observed. (Funded by the TB Alliance and others; ClinicalTrials.gov number, NCT02333799.).


Asunto(s)
Antituberculosos/administración & dosificación , Diarilquinolinas/administración & dosificación , Tuberculosis Extensivamente Resistente a Drogas/tratamiento farmacológico , Linezolid/administración & dosificación , Nitroimidazoles/administración & dosificación , Administración Oral , Adolescente , Adulto , Antituberculosos/efectos adversos , Carga Bacteriana , Diarilquinolinas/efectos adversos , Quimioterapia Combinada , Tuberculosis Extensivamente Resistente a Drogas/mortalidad , Femenino , Humanos , Análisis de Intención de Tratar , Linezolid/efectos adversos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis/aislamiento & purificación , Nitroimidazoles/efectos adversos , Resultado del Tratamiento , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Pulmonar/tratamiento farmacológico , Adulto Joven
2.
Sci Total Environ ; 714: 136768, 2020 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-31982761

RESUMEN

Real-time bacteriological counting technology is capable of providing an online profile of bacterial removal during the wastewater treatment process, and can enhance the safety of recycled water for potable water reuse. However, autofluorescence emanating from dissolved organic compounds present in treated wastewater interferes with the analysis. In this study, a novel approach is adopted, viz., dialysis treatment for the removal of dissolved interfering substances from treated wastewater, and the efficiency of this treatment protocol is evaluated as a pre-treatment technique for real-time bacteriological counting. Dialysis using membranes having a molecular weight cut-off (MWCO) of 1000 kDa and 6-8 kDa were found to successfully reduce the intensity of autofluorescence emitted from the interfering substances; whereas the courser dialysis membrane having a MWCO of 1000 kDa was found to be more effective in removing the interfering substances. Here we demonstrate for the first time that continuous online dialysis treatment aids in the direct determination of the bacterial counts in ultrafiltration- and membrane bioreactor-treated wastewaters. The results of the study indicate that the dialysis pre-treatment technique is effective for continuously reducing the concentration of interfering substances in treated wastewater, and thus allows for direct online counting of bacteria.


Asunto(s)
Carga Bacteriana , Reactores Biológicos , Diálisis , Membranas Artificiales , Ultrafiltración , Aguas Residuales , Purificación del Agua
3.
J Appl Oral Sci ; 28: e20190100, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31800872

RESUMEN

OBJECTIVE: This clinical study sought to evaluate the effectiveness of passive ultrasonic activation (PUA) in eliminating microorganisms in primary endodontic infection (PEI) after instrumentation of root canals using microbiological culture and checkerboard DNA-DNA hybridization. METHODOLOGY: Twenty root canals with PEI and apical periodontitis were selected. The root canals were instrumented and then randomly divided into 2 groups, according to the irrigation method: PUA and conventional needle irrigation (CNI). Microbiological samples were collected before instrumentation (S1), after instrumentation (S2) and after irrigation with 17% EDTA (S3). The samples were subjected to anaerobic culture technique and checkerboard DNA-DNA hybridization analysis. RESULTS: A statistically significant difference was found between CNI (23.56%) and PUA (98.37%) regarding the median percentage values for culturable bacteria reduction (p<0.05). In the initial samples, the most frequently detected species was S. constellatus (50%), and after root canal treatment was E. faecalis (50%). CONCLUSION: Both treatments significantly decreased the number of bacterial species compared with the initial sample. However, no statistical difference in the total microbial load between PUA and CNI groups was detected. The number of cultivable anaerobic bacteria reduced significantly using PUA, and the bacterial composition and number of bacterial species after using either CNI or PUA was similar.


Asunto(s)
Cavidad Pulpar/microbiología , Periodontitis Periapical/terapia , Tratamiento del Conducto Radicular/instrumentación , Terapia por Ultrasonido/instrumentación , Adolescente , Adulto , Análisis de Varianza , Bacterias/aislamiento & purificación , Carga Bacteriana , Recuento de Colonia Microbiana , Tomografía Computarizada de Haz Cónico , Sondas de ADN , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Irrigantes del Conducto Radicular/uso terapéutico , Tratamiento del Conducto Radicular/métodos , Hipoclorito de Sodio/uso terapéutico , Irrigación Terapéutica/instrumentación , Irrigación Terapéutica/métodos , Resultado del Tratamiento , Terapia por Ultrasonido/métodos , Adulto Joven
4.
J Appl Oral Sci ; 28: e20190266, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31800877

RESUMEN

OBJECTIVE: The microbial composition of pericoronitis (Pc) is still controversial; it is not yet clear if the microbial profile of these lesions is similar to the profile observed in periodontitis (Pd). Therefore, the aim of the present study was to describe the microbial profile of Pc lesions and compare it directly with that of subjects with Pd. METHODOLOGY: Subjects with Pc and Pd were selected, and subgingival biofilm samples were collected from (i) third molars with symptomatic Pc (Pc-T), (ii) contralateral third molars without Pc (Pc-C) and (iii) teeth with a probing depth >3 mm from subjects with Pd. Counts and proportions of 40 bacterial species were evaluated using a checkerboard DNA-DNA hybridization technique. RESULTS: Twenty-six patients with Pc and 18 with Pd were included in the study. In general, higher levels of microorganisms were observed in Pd. Only Actinomyces oris and Eubacterium nodatum were present in higher mean counts in the Pc-T group in comparison with the Pc-C and Pd-C groups (p<0.05). The microbiota associated with Pc-T was similar to that found in Pc-C. Sites with Pc lesions had lower proportions of red complex in comparison with the Pd sites. CONCLUSION: The microbiota of Pc is very diverse, but these lesions harbour lower levels of periodontal pathogens than Pd.


Asunto(s)
Bacterias/aislamiento & purificación , Pericoronitis/microbiología , Periodontitis/microbiología , Análisis por Activación , Adulto , Anciano , Carga Bacteriana , Biopelículas , Estudios Transversales , Sondas de ADN , Femenino , Encía/microbiología , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Adulto Joven
5.
Clin Anat ; 33(1): 113-116, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31576617

RESUMEN

Safety is a major issue in the embalming procedures of human cadavers. Reduced application of formaldehyde is often recommended. The aim of this study was to investigate the potency of ultraviolet light (UV-C irradiation) on the bacterial load on the surface of a conserved human cadaver. To test UV-C irradiation, the cadaver was laid out in the dissection hall and, after preparation of the muscles, was covered with linen sheets moistened with water. Swabs of the surface and microbiological analysis revealed sporadic bacterial colonies. The surface area was then spiked with bacteria and irradiated by a UV lamp for 15 or 60 min. Half of the area was covered by aluminum foil to serve as a control. After exposition, swabs were taken and analyzed. The exposition had reduced the number of colonies to one third (15 min exposition) and to one tenth (60 min exposition) of the control area. Thus, UV-C irradiation could be used in the preservation of cadavers without chemical pollution of the environment and without any risk for the employees. Clin. Anat. 32:113-116, 2019. © 2019 Wiley Periodicals, Inc.


Asunto(s)
Carga Bacteriana/efectos de la radiación , Desinfección/métodos , Embalsamiento/métodos , Rayos Ultravioleta , Anciano , Cadáver , Humanos , Masculino
6.
Food Microbiol ; 85: 103282, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500713

RESUMEN

Two biopreservation approaches for fresh lettuce, rocket salad, parsley and spinach were studied. The potential of Pediococcus pentosaceus DT016, as a protective culture, to suppress Listeria monocytogenes in vegetables during storage was evaluated. The pathogen numbers in the vegetables inoculated with P. pentosaceus DT016 were significantly (p < 0.01) lower throughout the storage period and, at the last storage day, a minimum difference of 1.4 log CFU/g was reported when compared with the vegetables without the protective culture. Moreover, by using two levels of L. monocytogenes (about 6 and 4 log CFU/g), it was observed that the antagonist effect of P. pentosaceus was higher for the lower pathogen numbers. The second approach evaluated a pediocin DT016 solution to inactivate and control L. monocytogenes proliferation. The pathogen load was studied after washing with: water, chlorine and the pediocin solution and along storage at 4  °C. Comparing the various washing solutions, the vegetables washed with pediocin presented significantly (p < 0.01) lower pathogen numbers throughout storage, by a minimum of 3.2 and 2.7 log CFU/g, than in vegetables washed with water and chlorine, respectively. The proposed methodologies are promising alternatives to maintain the safety of fresh vegetables during extended storage at refrigeration temperature.


Asunto(s)
Antibiosis , Microbiología de Alimentos/métodos , Conservación de Alimentos/métodos , Listeria monocytogenes/fisiología , Verduras/microbiología , Carga Bacteriana , Cloro/farmacología , Frío , Seguridad de Productos para el Consumidor , Manipulación de Alimentos/métodos , Lechuga/microbiología , Listeria monocytogenes/efectos de los fármacos , Listeria monocytogenes/crecimiento & desarrollo , Pediocinas/farmacología , Pediococcus pentosaceus/fisiología , Petroselinum/microbiología , Refrigeración , Spinacia oleracea/microbiología , Agua
7.
Int J Food Microbiol ; 312: 108375, 2020 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-31669767

RESUMEN

Recently, oxo-biodegradable polymers have attracted much attention due to taking less time to break down after disposal in comparison to ordinary polymers. Polyvinyl alcohol/gelatin (PVA/G) nanocomposite films, containing ZnO, TiO2 or ZnO/TiO2 nanoparticles supported on 4A zeolite (4A z), are novel active packaging that can control the release of antimicrobial compounds. The present study assessed the efficacy of PVA/G nanocomposite films with 1.5% (w/w) ZnO/4A z (treatment 1), 1.5% (w/w) TiO2/4A z (treatment 2), or 1% (w/w) ZnO, TiO2/4A z (treatment 3) in controlling the microbial load and maintaining the sensory qualities of white shrimp during storage at 4 ±â€¯1 °C. Firstly, the optimum concentration of each material for addition to the film was determined by micro-dilution and disc diffusion. Secondly, the specimens were checked for total viable count (TVC), as well as the counts of each of Pseudomonas spp., Enterobacteriaceae, Shewanella putrefaciens, inoculated Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157:H7. According to the results, the PVA/G nanocomposite films containing treatments 1-3 significantly decreased the number of bacteria in the treatment group in comparison to the control group (P < .05). The results of the antimicrobial activity of the three treatments by using the disc diffusion method revealed that the inhibition zone varied from 8.11 ±â€¯0.02 to 12.63 ±â€¯0.04 mm. Also it should be noted that, the finding of micro-dilution test varied from 1 ±â€¯0.01 to 3 ±â€¯0.01. The ZnO, TiO2/4A z nanocomposite had a significantly greater antimicrobial impact against Gram-negative bacteria compared to Gram-positive bacteria (P < .05). Finally, the microbiological and sensory investigation of the efficacy of the PVA/G nanocomposite films as active packaging materials revealed a considerable improvement in shrimp shelf life (12 days) in comparison to the control (6 days). Therefore, these nanocomposite films can be used as novel active packaging in the maintenance of the microbial load and sensory qualities of shrimp.


Asunto(s)
Antibacterianos/farmacología , Embalaje de Alimentos/métodos , Almacenamiento de Alimentos/métodos , Penaeidae/microbiología , Titanio/farmacología , Zeolitas/farmacología , Óxido de Zinc/farmacología , Animales , Carga Bacteriana/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Gelatina/farmacología , Listeria monocytogenes/efectos de los fármacos , Nanocompuestos , Nanopartículas , Alcohol Polivinílico/farmacología , Refrigeración , Staphylococcus aureus/efectos de los fármacos
8.
Immunology ; 159(1): 121-129, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31606895

RESUMEN

The transcription factor hypoxia-inducible factor-1 alpha (HIF-1α) is a key regulator of the response and function of myeloid cells in hypoxic and inflammatory microenvironments. To define the role of HIF-1α in tuberculosis, the progression of aerosol Mycobacterium tuberculosis infection was analysed in mice deficient in HIF-1α in the myeloid lineage (mHIF-1α-/- ). We show that myeloid HIF-1α is not required for the containment of the infection, as both wild-type (WT) and mHIF-1α-/- mice mounted normal Th1 responses and maintained control of bacterial growth throughout infection. However, during chronic infection mHIF-1α-/- mice developed extensive lymphocytic inflammatory involvement of the interstitial lung tissue and died earlier than WT mice. These data support the hypothesis that HIF-1α activity coordinates the response of myeloid cells during M. tuberculosis infection to prevent excessive leucocyte recruitment and immunopathological consequences to the host.


Asunto(s)
Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Pulmón/metabolismo , Mycobacterium tuberculosis/crecimiento & desarrollo , Células Mieloides/metabolismo , Neumonía/metabolismo , Tuberculosis Pulmonar/metabolismo , Animales , Carga Bacteriana , Células Cultivadas , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Interacciones Huésped-Patógeno , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Pulmón/inmunología , Pulmón/microbiología , Ratones Endogámicos C57BL , Ratones Noqueados , Mycobacterium tuberculosis/inmunología , Células Mieloides/inmunología , Células Mieloides/microbiología , Neumonía/genética , Neumonía/inmunología , Neumonía/microbiología , Transducción de Señal , Tuberculosis Pulmonar/genética , Tuberculosis Pulmonar/inmunología , Tuberculosis Pulmonar/microbiología
9.
Niger J Clin Pract ; 22(12): 1654-1661, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31793470

RESUMEN

Background: Incomplete eradication of plaque bacteria from the plaque retentive sites and the emerging problem of antibiotic resistance led the scientific community to explore new antimicrobial strategies for improved results and shun antibiotic resistance. Objective: The purpose of this in-vitro study was to evaluate the antimicrobial effect of a novel light based therapy and to assess the susceptibility of oral plaque bacteria to light based technologies with and without photosensitizers. Materials and Methods: Four oral plaque bacterial strains were isolated from the dental plaque sample collected from the patients and exposed to various light based technologies and photodynamic therapy (PDT) with and without photosensitizers. The cultures were analysed for viable colony forming unit (CFU) counts. One-way analysis of variance was used to statistically analyse differences and the Student-Newman-Keuls method to perform multiple comparison procedures. Results: All groups showed remarkable reduction in the CFUs as compared to control group with use of light based technologies and PDT in this study. The difference of antimicrobial effect between all tested groups either with light based technologies and PDT with control group showed significant reduction in CFUs. Conclusions: From the results of this study, we concluded that light based technologies and PDT could be a valuable alternative therapy to mechanical debridement in the prevention of growth and recolonisation of oral plaque bacteria.


Asunto(s)
Antiinfecciosos/farmacología , Bacterias/efectos de los fármacos , Placa Dental/microbiología , Placa Dental/terapia , Bolsa Periodontal/microbiología , Fotoquimioterapia/métodos , Fármacos Fotosensibilizantes/farmacología , Bacterias/clasificación , Bacterias/aislamiento & purificación , Carga Bacteriana/efectos de los fármacos , Placa Dental/tratamiento farmacológico , Cavidad Pulpar/efectos de los fármacos , Cavidad Pulpar/microbiología , Humanos , Técnicas In Vitro , Azul de Metileno/administración & dosificación , Azul de Metileno/uso terapéutico , Bolsa Periodontal/terapia , Fármacos Fotosensibilizantes/administración & dosificación , Fármacos Fotosensibilizantes/uso terapéutico , Titanio
10.
Rev Lat Am Enfermagem ; 27: e3211, 2019.
Artículo en Inglés, Portugués, Español | MEDLINE | ID: mdl-31826156

RESUMEN

OBJECTIVE: to evaluate the potential contamination of enzymatic detergent from its reuse and to identify the microbiological profile in the solution used to clean gastrointestinal endoscopic devices. METHOD: cross-sectional study based on microbiological analysis of 76 aliquots of 19 different enzymatic detergent solutions used to clean endoscopic devices. The aliquots were homogenized, subjected to Millipore® 0.45 µm membrane filtration and the presumptive identification of microorganisms was performed by biochemical-physiological methods according to previously established specific bacterial groups that are of clinical and epidemiological relevance. RESULTS: the mean values, as well as the standard deviation and the median, of the enzymatic detergent microbial load increased as the solution was reused. There was a significant difference between the means of after first use and after fifth reuse. A total of 97 microorganisms were identified, with predominance of the coagulase-negative Staphylococcus, Pseudomonas spp., Klebsiella spp., Enterobacter spp. genus, and Escherichia coli species. CONCLUSION: the reuse of the enzymatic detergent solution is a risk to the safe processing of endoscopic devices, evidenced by its contamination with pathogenic potential microorganisms, since the enzymatic detergent has no bactericidal property and can contribute as an important source for outbreaks in patients under such procedures.


Asunto(s)
Detergentes/efectos adversos , Contaminación de Equipos , Gastroscopios/efectos adversos , Gastroscopios/microbiología , Carga Bacteriana , Estudios Transversales , Detergentes/farmacología , Transmisión de Enfermedad Infecciosa , Bacterias Gramnegativas/clasificación , Bacterias Gramnegativas/aislamiento & purificación , Bacterias Grampositivas/clasificación , Bacterias Grampositivas/aislamiento & purificación , Humanos , Control de Infecciones
11.
PLoS One ; 14(12): e0226574, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31877146

RESUMEN

Phage therapy offers a potential alternate strategy for the treatment of peri-prosthetic joint infection (PJI), particularly where limited effective antibiotics are available. We undertook preclinical trials to investigate the therapeutic efficacy of a phage cocktail, alone and in combination with vancomycin, to reduce bacterial numbers within the infected joint using a clinically-relevant model of Staphylococcus aureus-induced PJI. Infected animals were randomised to 4 treatment groups, with treatment commencing 21-days post-surgery: bacteriophage alone, vancomycin alone, bacteriophage and vancomycin, and sham. At day 28 post-surgery, animals were euthanised for microbiological and immunological assessment of implanted joints. Treatment with phage alone or vancomycin alone, led to 5-fold and 6.2-fold reductions, respectively in bacterial load within peri-implant tissue compared to sham-treated animals. Compared to sham-treated animals, a 22.5-fold reduction in S. aureus burden was observed within joint tissue of animals that were administered phage in combination with vancomycin, corresponding with decreased swelling in the implanted knee. Microbiological data were supported by evidence of decreased inflammation within the joints of animals administered phage in combination with vancomycin, compared to sham-treated animals. Our findings provide further support for phage therapy as a tolerable and effective adjunct treatment for PJI.


Asunto(s)
Bacteriófagos/fisiología , Infecciones Relacionadas con Prótesis/terapia , Infecciones Estafilocócicas/terapia , Staphylococcus aureus/patogenicidad , Vancomicina/administración & dosificación , Animales , Carga Bacteriana/efectos de los fármacos , Terapia Combinada , Modelos Animales de Enfermedad , Masculino , Infecciones Relacionadas con Prótesis/microbiología , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/efectos de los fármacos , Resultado del Tratamiento , Vancomicina/farmacología
12.
BMC Infect Dis ; 19(1): 923, 2019 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-31666021

RESUMEN

BACKGROUND: Pulmonary tuberculosis (TB) with detectable Mycobacterium tuberculosis in the sputum is a major source of transmission. In resource limited TB endemic settings, cure is declared through sputum smear examination for acid fast bacilli without performing culture. This may lead to erroneous treatment outcomes as viable bacteria may be missed due to the low sensitivity of direct smear method. The aim of this study was to investigate if sterilizing cure is achieved among the new pulmonary TB cases declared cured by sputum smear conversion and to evaluate the impact of addition of ethambutol in the continuation phase in achieving it. METHODS: New sputum smear-positive pulmonary TB patients registered at a tertiary care hospital in Pakistan from November 2013 to March 2014 were followed under standard Directly Observed Treatment Short Course strategy for 6 months. Half of these patients received ethambutol in addition to isoniazid and rifampicin in the continuation phase. Sputum specimens were examined on microscopy at 2 months and at the end of treatment. Sputa of patients with negative direct smear examination at the end of treatment were cultured. RESULTS: Among 5746 TB suspects, 1595 were new sputum smear positive pulmonary TB cases, and 533 were registered at our hospital. Among these, 504 converted sputum negative at 2 months and 348 converted at the end of 6 months of treatment and were declared cured. Sputa of 204/348 patients were cultured, and 12/204 (6%) were culture-positive. Culture positivity at 6 months was not associated with bacterial load, smoking, diabetes, presence of cavities, history of contact with TB patients, age, sex, socioeconomic status, or addition of ethambutol in the continuation phase. CONCLUSION: Viable cultivable bacilli were detected in 6% of cured patients, which would have significant impact on the control of TB. This highlights the need for an inexpensive and accurate surrogate marker for culture as it is not feasible to perform culture in routine for monitoring treatment response in the low-resource settings. The treatment outcome did not improve by addition of ethambutol emphasizing the need to find the optimal duration of treatment for individual or carefully selected groups of patients.


Asunto(s)
Antituberculosos/uso terapéutico , Etambutol/uso terapéutico , Mycobacterium tuberculosis/aislamiento & purificación , Esputo/microbiología , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/microbiología , Adolescente , Adulto , Anciano , Carga Bacteriana , Pruebas Diagnósticas de Rutina , Quimioterapia Combinada , Femenino , Humanos , Isoniazida/uso terapéutico , Masculino , Persona de Mediana Edad , Pakistán , Rifampin/uso terapéutico , Resultado del Tratamiento , Tuberculosis Pulmonar/diagnóstico por imagen , Adulto Joven
13.
FEMS Microbiol Lett ; 366(23)2019 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-31750894

RESUMEN

Symbiosis between intracellular bacteria (endosymbionts) and animals are widespread. The alphaproteobacterium Wolbachia pipientis is known to maintain a variety of symbiotic associations, ranging from mutualism to parasitism, with a wide range of invertebrates. Wolbachia infection might deeply affect host fitness (e.g. reproductive manipulation and antiviral protection), which is thought to explain its high prevalence in nature. Bacterial loads significantly influence both the infection dynamics and the extent of bacteria-induced host phenotypes. Hence, fine regulation of bacterial titers is considered as a milestone in host-endosymbiont interplay. Here, we review both environmental and biological factors modulating Wolbachia titers in arthropods.


Asunto(s)
Artrópodos/microbiología , Simbiosis/fisiología , Wolbachia/fisiología , Animales , Carga Bacteriana , Ambiente
14.
Int J Nanomedicine ; 14: 6707-6719, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31692512

RESUMEN

Background: Tuberculosis is the leading cause of death by an infectious microorganism worldwide. Conventional treatment lasts at least six months and has adverse effects; therefore, it is important to find therapeutic alternatives that reduce the bacterial load and may reduce the treatment duration. The immune response against tuberculosis can be modulated by several mechanisms, including extracellular vesicles (EVs), which are nano-sized membrane-bound structures that constitute an efficient communication mechanism among immune cells. Methods: The EVs released by the J774A.1 mouse macrophage cell line, both spontaneously (S-EV) and after infection with Mycobacterium tuberculosis H37Rv (Mtb-EV), were purified by ultra-centrifugation and size-exclusion chromatography. The size distribution and chemical composition of these EVs were evaluated, and their effect on the bacterial load and the production of cytokines was determined in both in vitro and in vivo models of M. tuberculosis infection. Results: Mtb-EV are larger than S-EV, they contain M. tuberculosis-specific antigens (not detected in EVs released from M. fortuitum-infected J774A.1 cells) and are rich in phosphatidylserine, present in their outer membrane layer. S-EV, but not Mtb-EV, reduced the bacterial load and the production of MCP-1 and TNF-α in M. tuberculosis-infected macrophages, and these effects were reversed when phosphatidylserine was blocked with annexin V. Both S-EV and Mtb-EV significantly reduced the lung bacterial load in mice infected with M. tuberculosis after 60 days of treatment, but they had no effect on survival or on the lung pneumonic area of these mice. Conclusion: J774A.1 macrophages infected with M. tuberculosis H37Rv released EVs that differed in size and phosphatidylserine content from spontaneously released EVs, and these EVs also had different biological effects: S-EV reduced the mycobacterial load and the cytokine production in vitro (through a phosphatidylserine-dependent mechanism), while both EVs reduced the lung bacterial load in vivo. These results are the basis for further experiments to evaluate whether EVs improve the efficiency of the conventional treatment for tuberculosis.


Asunto(s)
Vesículas Extracelulares/metabolismo , Macrófagos/metabolismo , Macrófagos/microbiología , Tuberculosis/terapia , Animales , Carga Bacteriana , Línea Celular , Citocinas/metabolismo , Modelos Animales de Enfermedad , Vesículas Extracelulares/química , Vesículas Extracelulares/trasplante , Masculino , Ratones Endogámicos BALB C , Mycobacterium tuberculosis/patogenicidad , Tuberculosis/microbiología
15.
Infect Immun ; 88(1)2019 12 17.
Artículo en Inglés | MEDLINE | ID: mdl-31636138

RESUMEN

Salmonella is an intracellular bacterium found in the gastrointestinal tract of mammalian, avian, and reptilian hosts. Mouse models have been extensively used to model in vivo distinct aspects of human Salmonella infections and have led to the identification of several host susceptibility genes. We have investigated the susceptibility of Collaborative Cross strains to intravenous infection with Salmonella enterica serovar Typhimurium as a model of human systemic invasive infection. In this model, strain CC042/GeniUnc (CC042) mice displayed extreme susceptibility with very high bacterial loads and mortality. CC042 mice showed lower spleen weights and decreased splenocyte numbers before and after infection, affecting mostly CD8+ T cells, B cells, and all myeloid cell populations, compared with control C57BL/6J mice. CC042 mice also had lower thymus weights with a reduced total number of thymocytes and double-negative and double-positive (CD4+, CD8+) thymocytes compared to C57BL/6J mice. Analysis of bone marrow-resident hematopoietic progenitors showed a strong bias against lymphoid-primed multipotent progenitors. An F2 cross between CC042 and C57BL/6N mice identified two loci on chromosome 7 (Stsl6 and Stsl7) associated with differences in bacterial loads. In the Stsl7 region, CC042 carried a loss-of-function variant, unique to this strain, in the integrin alpha L (Itgal) gene, the causative role of which was confirmed by a quantitative complementation test. Notably, Itgal loss of function increased the susceptibility to S. Typhimurium in a (C57BL/6J × CC042)F1 mouse background but not in a C57BL/6J mouse inbred background. These results further emphasize the utility of the Collaborative Cross to identify new host genetic variants controlling susceptibility to infections and improve our understanding of the function of the Itgal gene.


Asunto(s)
Bacteriemia/genética , Antígeno CD11a/deficiencia , Predisposición Genética a la Enfermedad , Mutación con Pérdida de Función , Infecciones por Salmonella/genética , Salmonella typhimurium/crecimiento & desarrollo , Animales , Bacteriemia/inmunología , Bacteriemia/patología , Carga Bacteriana , Médula Ósea/patología , Modelos Animales de Enfermedad , Genes , Subgrupos Linfocitarios/inmunología , Ratones , Ratones Endogámicos C57BL , Infecciones por Salmonella/inmunología , Infecciones por Salmonella/patología , Serogrupo , Bazo/patología , Análisis de Supervivencia , Timo/patología
16.
Infect Immun ; 88(1)2019 12 17.
Artículo en Inglés | MEDLINE | ID: mdl-31591166

RESUMEN

The avian pathogen Mycoplasma gallisepticum, the etiological agent of chronic respiratory disease in chickens, exhibits enhanced pathogenesis in the presence of a copathogen such as low-pathogenic avian influenza virus (LPAIV). To further investigate the intricacies of this copathogenesis, chickens were monoinfected or coinfected with either virulent M. gallisepticum strain Rlow or LPAIV H3N8 (A/duck/Ukraine/1963), with assessment of tracheal histopathology, pathogen load, and transcriptomic host responses to infection by RNA sequencing. Chickens coinfected with M. gallisepticum Rlow followed by LPAIV H3N8 exhibited significantly more severe tracheal lesions and mucosal thickening than chickens infected with LPAIV H3N8 alone and greater viral loads than chickens infected first with H3N8 and subsequently with M. gallisepticum Rlow Recovery of live M. gallisepticum was significantly higher in chickens infected first with LPAIV H3N8 and then with M. gallisepticum Rlow, compared to chickens given a mock infection followed by M. gallisepticum Rlow The transcriptional responses to monoinfection and coinfection with M. gallisepticum and LPAIV highlighted the involvement of differential expression of genes such as Toll-like receptor 15, Toll-like receptor 21, and matrix metallopeptidase 1. Pathway and gene ontology analyses of these differentially expressed genes suggest that coinfection with virulent M. gallisepticum and LPAIV induces decreases in the expression of genes related to ciliary activity in vivo and alters multiple immune-related signaling cascades. These data aid in the understanding of the relationship between M. gallisepticum and LPAIV during copathogenesis in the natural host and may contribute to further understanding of copathogen infections of humans and other animals.


Asunto(s)
Coinfección/patología , Gripe Aviar/patología , Infecciones por Mycoplasma/patología , Enfermedades de las Aves de Corral/patología , Tráquea/patología , Animales , Carga Bacteriana , Pollos , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Histocitoquímica , Interacciones Huésped-Patógeno , Virus de la Influenza A/crecimiento & desarrollo , Gripe Aviar/complicaciones , Infecciones por Mycoplasma/complicaciones , Mycoplasma gallisepticum/crecimiento & desarrollo , Carga Viral
17.
J Dairy Sci ; 102(12): 11384-11400, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31606215

RESUMEN

Objectives of this study were to (1) describe the intramammary infection (IMI) prevalence and pathogen profiles in quarters of cows approaching dry-off in US dairy herds, (2) compare IMI prevalence in quarters of cows exposed to different bedding material types, and (3) identify associations between bedding bacteria count and IMI in cows approaching dry-off. Eighty herds using 1 of 4 common bedding materials (manure solids, organic non-manure, new sand, and recycled sand) were recruited in a multi-site cross-sectional study. Each herd was visited twice for sampling. At each visit, aseptic quarter-milk samples were collected from 20 cows approaching dry-off (>180 d pregnant). Samples of unused and used bedding were also collected. Aerobic culture was used to determine the IMI status of 10,448 quarters and to enumerate counts (log10 cfu/mL) of all bacteria, Staphylococcus spp., Streptococcus spp. and Streptococcus-like organisms (SSLO), coliforms, Klebsiella spp., noncoliform gram-negatives, Bacillus spp., and Prototheca spp. in unused (n = 148) and used (n = 150) bedding. The association between bedding bacteria count and IMI was determined using multivariable logistic regression with mixed effects. Quarter-level prevalence of IMI was 21.1%, which was primarily caused by non-aureus Staphylococcus spp. (11.4%) and SSLO (5.6%). Only modest differences in IMI prevalence were observed between the 4 common bedding material types. Counts of all bacteria in unused bedding was positively associated with odds of IMI caused by any pathogen [ALL-IMI; odds ratio (OR) = 1.08]. A positive association was also observed for counts of SSLO in unused bedding and SSLO-IMI (OR = 1.09). These patterns of association were generally consistent across the 4 common bedding materials. In contrast, the association between counts of all bacteria in used bedding and ALL-IMI varied by bedding type, with positive associations observed in quarters exposed to manure solids (OR = 2.29) and organic non-manure (OR = 1.51) and a negative association in quarters exposed to new sand (OR = 0.47). Findings from this study suggest that quarter-level IMI prevalence in late-lactation cows is low in US dairy herds. Furthermore, bedding material type may not be an important risk factor for IMI in late lactation. Higher levels of bacteria in bedding may increase IMI prevalence at dry-off in general, but this relationship is likely to vary according to bedding material type.


Asunto(s)
Infecciones por Klebsiella/veterinaria , Mastitis Bovina/microbiología , Leche/microbiología , Infecciones Estafilocócicas/veterinaria , Infecciones Estreptocócicas/veterinaria , Animales , Carga Bacteriana/veterinaria , Ropa de Cama y Ropa Blanca/microbiología , Ropa de Cama y Ropa Blanca/veterinaria , Bovinos , Estudios Transversales , Femenino , Klebsiella/aislamiento & purificación , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/microbiología , Lactancia , Modelos Logísticos , Glándulas Mamarias Animales/microbiología , Estiércol/microbiología , Mastitis Bovina/epidemiología , Prevalencia , Factores de Riesgo , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Staphylococcus/aislamiento & purificación , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/microbiología , Streptococcus/aislamiento & purificación
18.
J Dairy Sci ; 102(12): 11401-11413, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31606221

RESUMEN

Because cloth udder towels (CUT) may function as a fomite for mastitis-causing pathogens, most udder health laboratories offer towel culture services as a tool to monitor towel hygiene. However, no studies have investigated if an association exists between bacteria levels in CUT and udder health outcomes. The objectives of this cross-sectional study were to (1) describe associations between herd-level measures of towel bacteria count (ToBC) and quarter-level intramammary infection (IMI) status in late-lactation cows, (2) establish pathogen-specific target levels of bacteria in CUT to aid the interpretation of towel culture reports, and (3) identify laundering-related risk factors for high ToBC. The study was conducted in 67 herds from 10 dairy states in the United States that used CUT. These 67 herds were originally recruited as part of a larger (80 herd) cross-sectional study of bedding management. Each herd was visited once during December 2017 to April 2018 and quarter-milk samples (n = 4,656) were collected from late-gestation (>180 d pregnant) cows (n = 1,313). Two recently laundered CUT were collected and a questionnaire was used to collect information about pre-milking teat preparation and CUT management practices. Quarter-level IMI status was determined using standard bacteriologic methods. In addition, colony-forming units of all bacteria (total bacteria), Staphylococcus spp., Streptococcus spp. or Streptococcus-like organisms (SSLO), coliforms, noncoliform gram-negatives, and Bacillus spp. were determined for each pair of CUT (log10 cfu/cm2). The association between ToBC and IMI was determined using multivariable logistic regression with mixed effects. After dichotomizing ToBC into high and low categories, associations between towel management practices and ToBC category were determined using unconditional logistic regression. The quarter-level prevalence of IMI was 19.6%, which was predominantly caused by non-aureus Staphylococcus spp. (NAS; 10.2%) and SSLO (5.1%). The predominant bacteria in CUT were Bacillus spp. (median = 3.13 log10 cfu/cm2). Total bacteria count was not associated with odds of IMI (odds ratio = 1.06), likely due to the predominance of Bacillus spp. in CUT and low number of IMI caused by Bacillus spp. In contrast, counts of Staphylococcus spp. and SSLO were positively associated with odds of IMI caused by NAS (odds ratio = 1.33) and SSLO (odds ratio = 1.45), respectively. Of 12 CUT management practices evaluated, only the failure to use a dryer was identified as a clear predictor of risk for a high ToBC (risk ratio of high coliform count = 8.17). Our study findings suggest that CUT may act as a fomite for NAS and SSLO. We recommend that herds aim to keep counts of Staphylococcus spp. and SSLO in CUT below 32 cfu/cm2 (or 5 cfu/in2), and that laundered towels be completely dried in a hot air dryer.


Asunto(s)
Infecciones por Klebsiella/veterinaria , Mastitis Bovina/microbiología , Leche/microbiología , Infecciones Estafilocócicas/veterinaria , Infecciones Estreptocócicas/veterinaria , Animales , Carga Bacteriana/veterinaria , Bovinos , Estudios Transversales , Femenino , Klebsiella/aislamiento & purificación , Infecciones por Klebsiella/epidemiología , Infecciones por Klebsiella/microbiología , Lactancia , Modelos Logísticos , Glándulas Mamarias Animales/microbiología , Estiércol/microbiología , Mastitis Bovina/epidemiología , Embarazo , Prevalencia , Factores de Riesgo , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Staphylococcus/aislamiento & purificación , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/microbiología , Streptococcus/aislamiento & purificación
19.
Artículo en Inglés | MEDLINE | ID: mdl-31614843

RESUMEN

The effects of hydrodynamic disturbances on the bacterial communities in eutrophic aquatic environments remain poorly understood, despite their importance to ecological evaluation and remediation. This study investigated the evolution of bacterial communities in the water-sediment systems under the influence of three typical velocity conditions with the timescale of 5 weeks. The results demonstrated that higher bacterial diversity and notable differences were detected in sediment compared to water using the 16S rRNA gene sequencing. The phyla Firmicutes and γ-Proteobacteria survived better in both water and sediment under stronger water disturbances. Their relative abundance peaked at 36.0%, 33.2% in water and 38.0%, 43.6% in sediment, respectively, while the phylum Actinobacteria in water had the opposite tendency. Its relative abundance grew rapidly in static control (SC) and peaked at 44.8%, and it almost disappeared in disturbance conditions. These phenomena were caused by the proliferation of genus Exiguobacterium (belonging to Firmicutes), Citrobacter, Acinetobacter, Pseudomonas (belonging to γ-Proteobacteria), and hgcI_clade (belonging to Actinobacteria). The nonmetric multidimensional scaling (NMDS) and Venn analysis also revealed significantly different evolutionary trend in the three water-sediment systems. It was most likely caused by the changes of geochemical characteristics (dissolved oxygen (DO) and nutrients). This kind of study can provide helpful information for ecological assessment and remediation strategy in eutrophic aquatic environments.


Asunto(s)
Bacterias/genética , Carga Bacteriana , Biodiversidad , Sedimentos Geológicos/microbiología , Hidrodinámica , Lagos/microbiología , Microbiología del Agua , China
20.
J Fish Dis ; 42(12): 1713-1730, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31625186

RESUMEN

The Chilean aquaculture has been challenged for years by piscirickettsiosis. A common prophylactic measurement to try to reduce the impact from this disease is vaccination, but the development of vaccines that induce satisfactory protection of the fish in the field has so far not been successful. Experimental challenge models are used to test vaccine efficacy. The aim of this study was to evaluate the performance of experimental vaccines after challenge by the two most widely used challenge routes, intraperitoneal injection and cohabitation. A total of 1,120 Atlantic salmon were vaccinated with non-commercial experimental vaccines with increasing amounts of an inactivated Piscirickettsia salmonis EM90-like isolate. Differences in mortality, macroscopic and microscopic pathological changes, bacterial load and immune gene expression were compared after challenge by different routes. The results revealed a similar progression of the diseases after challenge by both routes and no gross differences reflecting the efficacy of the vaccines could be identified. The analysis of the immune genes suggests a possible suppression of the cellular immunity by CD8 T cell and with this stimulation of bacterial survival and replication. Comparative studies of experimental challenge models are valuable with regard to identifying the best model to mimic real-life conditions and vaccines' performance.


Asunto(s)
Vacunas Bacterianas/uso terapéutico , Enfermedades de los Peces/prevención & control , Infecciones por Piscirickettsiaceae/veterinaria , Salmo salar/microbiología , Vacunación/veterinaria , Animales , Acuicultura , Carga Bacteriana , Enfermedades de los Peces/microbiología , Inyecciones Intraperitoneales , Piscirickettsia , Infecciones por Piscirickettsiaceae/prevención & control , Vacunación/métodos
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