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1.
Nat Commun ; 11(1): 4774, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32963224

RESUMO

Detection of microbial nucleic acids in body fluids has become the preferred method for rapid diagnosis of many infectious diseases. However, culture-based diagnostics that are time-consuming remain the gold standard approach in certain cases, such as sepsis. New culture-free methods are urgently needed. Here, we describe Single MOLecule Tethering or SMOLT, an amplification-free and purification-free molecular assay that can detect microorganisms in body fluids with high sensitivity without the need of culturing. The signal of SMOLT is generated by the displacement of micron-size beads tethered by DNA probes that are between 1 and 7 microns long. The molecular extension of thousands of DNA probes is determined with sub-micron precision using a robust and rapid optical approach. We demonstrate that SMOLT can detect nucleic acids directly in blood, urine and sputum at sub-femtomolar concentrations, and microorganisms in blood at 1 CFU mL-1 (colony forming unit per milliliter) threefold faster, with higher multiplexing capacity and with a more straight-forward protocol than amplified methodologies. SMOLT's clinical utility is further demonstrated by developing a multiplex assay for simultaneous detection of sepsis-causing Candida species directly in whole blood.


Assuntos
Líquidos Corporais/química , Técnicas de Diagnóstico Molecular/métodos , Ácidos Nucleicos/isolamento & purificação , Sepse/diagnóstico , Candida/genética , Candida/isolamento & purificação , Candidíase/diagnóstico , Contagem de Colônia Microbiana , Doenças Transmissíveis/diagnóstico , DNA/isolamento & purificação , Humanos , Ácidos Nucleicos/sangue , Ácidos Nucleicos/urina , Reação em Cadeia da Polimerase/métodos , RNA/isolamento & purificação , Sensibilidade e Especificidade , Sepse/microbiologia , Infecções Estafilocócicas/diagnóstico , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Urina
2.
Rev. Asoc. Odontol. Argent ; 108(2): 46-51, mayo-ago. 2020. tab
Artigo em Espanhol | LILACS | ID: biblio-1121108

RESUMO

Objetivos: Comparar ex vivo la eficacia del instrumento XP-endo Finisher y del sistema EndoActivator en la reducción/eliminación del biofilm microbiano en conductos radiculares infectados. Materiales y métodos: Se utilizaron 23 premolares inferiores humanos extraídos cuya longitud fue estandarizada en 17 mm. Todos los conductos se prepararon con el sistema WaveOne Gold Medium (#35.06). Los dientes se esterilizaron, se inocularon con Enterococcus faecalis y se separaron en dos grupos experimentales de 10 piezas cada uno. De los 3 dientes remanentes, 1 fue utilizado como control positivo y 2, como controles negativos. En el grupo 1, las soluciones irrigantes se agitaron con XP-endo Finisher. En el grupo 2, se utilizó EndoActivator. Se tomaron muestras antes de la contaminación, luego de esta y después de la agitación de los irrigantes mediante conos de papel estériles. La carga microbiana fue sembrada en agar sangre y los conos se cultivaron en caldo tripteína de soja. La remoción de la carga microbiana se determinó por la presencia o ausencia de turbiedad del medio. Las unidades formadoras de colonias (UFC) remanentes se cuantificaron y los resultados se categorizaron como R1 (≤10 UFC) o R2 (>10 UFC). Los datos fueron analizados mediante la prueba de Fisher. Resultados: No hubo diferencias significativas entre XP-endo Finisher y EndoActivator (P>0,05). El número de usos no influyó sobre la capacidad operativa de ambos instrumentos (AU)


Aim: To compare ex vivo the effectiveness of the XP-endo Finisher and the EndoActivator in biofilm reduction/ removal from infected root canals. Materials and methods: Twenty three extracted human single-rooted lower premolars were selected and standardised to 17 mm in length. All the canals were prepared with WaveOne Gold Medium reciprocating files (#35.06). The teeth were autoclaved and inoculated with Enterococcus faecalis. The infected teeth were then assigned to 2 experimental groups of 10 teeth each according to the final irrigation/agitation protocol. Of the three remaining teeth, one was used as a positive control, and the other two were used as negative controls. In Group 1 the irrigating solutions were agitated with XP-endo Finisher while in Group 2 the EndoActivator was used. All root canals were sampled before and after contamination, and again after irrigant agitation with sterile paper points. The microbial load was spread on blood agar plates and the paper points were cultured in sterile trypticase soy broth. The removal of the microbial load was determined by visual observation of the turbidity of the media and by quantification of the number of colony-forming units (UFC). The results were categorized as R1 (≤10 UFC) or R2 (>10 UFC). Data were analysed by the Fisher's exact test at P<0.05. Results: No significant differences was found between XP-endo Finisher and EndoActivator (P>0.05) regarding their effectiveness in the reduction/removal of the microbial biofilm. The number of uses of both instruments did not affect their operative performance (AU) Conclusion: XPF and EA were both equally effective for microbial biofilm reduction/removal from ex vivo infected root canals (AU)


Assuntos
Irrigantes do Canal Radicular/química , Equipamentos Odontológicos de Alta Rotação , Biofilmes , Instrumentos Odontológicos , Cavidade Pulpar/microbiologia , Técnicas In Vitro , Contagem de Colônia Microbiana/métodos , Eficácia , Análise Estatística , Enterococcus faecalis/isolamento & purificação , Meios de Cultura
3.
Indian J Dent Res ; 31(3): 420-425, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32769277

RESUMO

Background and Aims: Although Streptococcus mutans has been implicated as the major etiologic agent in the development of dental caries, however, this organism has not been found to be present in all children with caries. Thus it remains to be elucidated whether a single or specific consortium of bacteria is responsible for the caries process. The aim of this study is to evaluate the oral microflora of Indian children suffering from dental caries and to compare the same in children with no caries. Methods: The study was carried out on 67 out-patient 2-14 years old children who reported to the department of Paediatric Dentistry. Dental plaque samples from superficial and deep carious lesions and caries free surfaces in caries active children (n = 35) were collected using a sterile excavator in storage vials and subjected to various conventional and molecular microbial techniques. Caries free children (n = 32), who did not have any carious lesion served as controls. The data obtained was subjected to Pearson's Chi Square/Fischer's Exact tests to determine the statistical difference between the microflora of groups. Results: Main organisms isolated were: Streptococcal species mainly S anginosus, S salivarius, S gordonii: Lactobacilli spp; Coagulase negative Staphylococci, Staph epidermidis, Staph aureus. Other organisms such as Klebsiella spp, Acinetobacter, Enterococcus, E coli could also be found. There was a statistical difference in the frequency of isolation of non-mutans Streptococcal species (P = 0.008) and Lactobacilli species (P = 0.0001) in the two groups. Conclusions: The study suggests that caries activity in this population of children is associated with a diverse microbial flora without detectable S mutans. Main organisms associated with dental caries in this population are: Gram-positive cocci and bacilli mainly the non-mutans Streptococcus and Lactobacilli. Frequent consumption of sugar containing food promotes the presence and growth of cariogenic organisms.


Assuntos
Cárie Dentária , Placa Dentária , Adolescente , Criança , Pré-Escolar , Contagem de Colônia Microbiana , Técnicas de Cultura , Escherichia coli , Humanos , Reação em Cadeia da Polimerase , Streptococcus mutans
4.
Indian J Dent Res ; 31(3): 465-469, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32769284

RESUMO

Background: Microbial contamination of air in dental operatory is an important source of infection. In this study, passive air sampling using settle plates was used as an effective method to assess the microbial profile and index of microbial air contamination (IMA) in dental operatories. Aim: To assess the microbial profile and index of microbial air contamination (IMA) in dental operatories. Setting and Design: This study design was a experimental cum diagnosis study and was conducted in four outpatient dental operatories in a self-financing dental college using stratified random sampling technique. Materials and Methods: Twenty air samples were collected by leaving blood agar plates open for 1 h, 1 m above the floor and 1 m from the wall. After incubation at 37°C for 48 h, colonies were counted to assess the number of colony-forming units (CFUs) per plate. The number of CFU is the IMA. The evaluation of aerobic bacterial and fungal profiles of representative colonies was done by standard microbiological methods. Results: Independent sample 't' test was applied for this study. All air samples collected near the dental treatment unit showed more contamination than the ambient air. As per the IMA classes, the IMA near the dental treatment unit ranged from fair to poor. IMA of ambient air in all the four operatories was within the acceptable values. The most common microorganism isolated was Staphylococcus species. Conclusion: Passive air sampling is one of the effective ways of quantifying airborne bacteria as used in the present study. Air microbial level evaluation is a step towards cross-infection prevention.


Assuntos
Microbiologia do Ar , Infecção Hospitalar , Bactérias , Contagem de Colônia Microbiana , Contaminação de Equipamentos , Humanos
5.
PLoS One ; 15(8): e0235948, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785216

RESUMO

INTRODUCTION: Surgical site infection is one of the most severe complications of surgical treatments. However, the optimal procedure to prevent such infections remains uninvestigated. Ultraviolet radiation C (UVC) with a short wavelength has a high bactericidal effect; however, it is cytotoxic. Nonetheless, given that UVC with a wavelength of 222 nm reaches only the stratum corneum, it does not affect the skin cells. This study aimed to investigate the safety of 222-nm UVC irradiation and to examine its skin sterilization effect in healthy volunteers. METHODS: This trial was conducted on 20 healthy volunteers. The back of the subject was irradiated with 222-nm UVC at 50-500 mJ/cm2, and the induced erythema (redness of skin) was evaluated. Subsequently, the back was irradiated with a maximum amount of UVC not causing erythema, and the skin swabs before and after the irradiation were cultured. The number of colonies formed after 24 hours was measured. In addition, cyclobutene pyrimidine dimer (CPD) as an indicator of DNA damage was measured using skin tissues of the nonirradiated and irradiated regions. RESULTS: All subjects experienced no erythema at all doses. The back of the subject was irradiated at 500 mJ/cm2, and the number of bacterial colonies in the skin swab culture was significantly decreased by 222-nm UVC irradiation. The CPD amount produced in the irradiated region was slightly but significantly higher than that of the non-irradiated region. CONCLUSION: A 222-nm UVC at 500 mJ/cm2 was a safe irradiation dose and possessed bactericidal effects. In the future, 222-nm UVC irradiation is expected to contribute to the prevention of perioperative infection.


Assuntos
Dano ao DNA/efeitos da radiação , Microbiota/efeitos da radiação , Pele/efeitos da radiação , Esterilização/métodos , Raios Ultravioleta/efeitos adversos , Adulto , Dorso , Biópsia , Contagem de Colônia Microbiana , Eritema/diagnóstico , Eritema/etiologia , Voluntários Saudáveis , Humanos , Masculino , Dímeros de Pirimidina/análise , Dímeros de Pirimidina/efeitos da radiação , Pele/microbiologia , Infecção da Ferida Cirúrgica/microbiologia , Infecção da Ferida Cirúrgica/prevenção & controle , Resultado do Tratamento
6.
Water Res ; 183: 116102, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32745672

RESUMO

We report the existence and resuscitation of viable but nonculturable (VBNC) Escherichia coli O157:H7 cells in drinking water induced by the common point-of-use disinfection treatments of boiling or microwaving. Tap water and saline samples containing E. coli O157:H7 culturable cells from a bovine isolate or two clinical isolates were boiled (1, 10, or 15 min) on a hot plate or microwaved (1.5 min) to reach boiling. No culturable E. coli O157:H7 cells were observed in the treated samples using conventional plating methods. In samples boiled for 1 or 10 min, two viability assays separately detected that 2-5.5% of the cells retained an intact membrane, while 28 to 87 cells out of the initial 108 cells retained both measurable intracellular esterase activity and membrane integrity. In samples boiled for 15 min, no viable cells were detected. The microwaved samples contained 6-10% of cells with an intact membrane, while 21 to 108 cells out of the initial 108 cells retained both membrane integrity and esterase activity. The number of viable cells retaining both metabolic activity and membrane integrity were consistent in all samples, supporting the survival of a small number of E. coli O157:H7 cells in the VBNC state after boiling for 1 or 10 min or microwaving. Furthermore, the VBNC E. coli O157:H7 cells regained growth at 37 °C in culture media containing autoinducers produced by common non-pathogenic E. coli, commonly present in the human intestine, and norepinephrine. The resuscitated cells were culturable on conventional plates and expressed mRNA encoding the E. coli O157 lipopolysaccharide gene (rfbE) and the H7 flagellin gene (fliC). This study highlights potential concerns for public health risk management of VBNC E. coli O157:H7 in drinking water disinfected by heat treatment at point-of-use. The public health significance of these concerns warrants further investigation.


Assuntos
Escherichia coli O157 , Animais , Bovinos , Contagem de Células , Contagem de Colônia Microbiana , Meios de Cultura , Humanos , Micro-Ondas , Água
7.
Int J Nanomedicine ; 15: 4325-4331, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606680

RESUMO

Purpose: The purpose of this study was to investigate the effect of different commercially used dental materials (RelyX Luting Plus and Dyract Extra) mixed with either a metallic ionic solution or a colloidal suspension of metallic nanoparticles. Both the solution and the suspension contained a mixture of silver, copper, and lithium ions. Methods: The metal/ion-incorporated dental materials were prepared into disk-shaped samples and tested against the growth of Staphylococcus aureus. The susceptibility of bacteria against the antibacterial dental disks was tested using two methods: counting the colony-forming units per milliliter and disk diffusion (Kirby-Bauer). The incorporated materials (Dyract and Rely cement) were tested for ion release using flame atomic absorption spectroscopy. Results: Assessment showed efficient antibacterial activity of metal ion-incorporated Rely luting cement, exhibited by the formation of inhibition zones larger than those formed by the standard antibiotic, as well as a reduction in bacterial number of sevenfold after incubation for 24 hours. Dyract material incorporated with nanoparticles showed no significant clear zones and had no inhibiting effect on bacterial colony numbers after incubation for 24 hours. The release of silver, copper, and lithium metal ions depended on the type of both dental material and the incorporated nanoagents. The metal ion-incorporated Rely Plus cement released the highest levels of metal ions, which was attributed to its antibacterial efficiency. Conclusion: Rely Plus cement incorporated with the nanoparticle suspension demonstrated high antibacterial potency, due to the release of the highest concentrations of silver, copper, and lithium metal ions. This work is the first direct comparative study of dental materials with different forms of nanomixtures (metallic nanoparticles and soluble metallic ions) and their antibacterial effects after incubation with bacterial culture for 24 hours.


Assuntos
Materiais Dentários/farmacologia , Nanopartículas/química , Staphylococcus aureus/crescimento & desenvolvimento , Antibacterianos/farmacologia , Contagem de Colônia Microbiana , Humanos , Testes de Sensibilidade Microbiana , Staphylococcus aureus/efeitos dos fármacos
8.
Int J Nanomedicine ; 15: 4275-4288, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606677

RESUMO

Purpose: Selenium nanoparticles (Se NPs) are promising antibacterial agents to tackle the growing problem of antimicrobial resistance. The aim of this study was to fabricate Se NPs with a net positive charge to enhance their antibacterial efficacy. Methods: Se NPs were coated with a positively charged protein - recombinant spider silk protein eADF4(κ16) - to give them a net positive surface charge. Their cytotoxicity and antibacterial activity were investigated, with negatively charged polyvinyl alcohol coated Se NPs as a control. Besides, these eADF4(κ16)-coated Se NPs were immobilized on the spider silk films, and the antibacterial activity of these films was investigated. Results: Compared to the negatively charged polyvinyl alcohol coated Se NPs, the positively charged eADF4(κ16)-coated Se NPs demonstrated a much higher bactericidal efficacy against the Gram-negative bacteria E. coli, with a minimum bactericidal concentration (MBC) approximately 50 times lower than that of negatively charged Se NPs. Cytotoxicity testing showed that the eADF4(κ16)-coated Se NPs are safe to both Balb/3T3 mouse embryo fibroblasts and HaCaT human skin keratinocytes up to 31 µg/mL, which is much higher than the MBC of these particles against E. coli (8 ± 1 µg/mL). In addition, antibacterial coatings were created by immobilising the eADF4(κ16)-coated Se NPs on positively charged spider silk films and these were shown to retain good bactericidal efficacy and overcome the issue of low particle stability in culture broth. It was found that these Se NPs needed to be released from the film surface in order to exert their antibacterial effects and this release can be regulated by the surface charge of the film, such as the change of the spider silk protein used. Conclusion: Overall, eADF4(κ16)-coated Se NPs are promising new antibacterial agents against life-threatening bacteria.


Assuntos
Antibacterianos/farmacologia , Nanopartículas/química , Proteínas Recombinantes/farmacologia , Selênio/farmacologia , Seda/farmacologia , Células 3T3 , Animais , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Contagem de Colônia Microbiana , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Humanos , Queratinócitos/citologia , Queratinócitos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Nanopartículas/ultraestrutura , Tamanho da Partícula
9.
Bone Joint J ; 102-B(7_Supple_B): 3-10, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32600192

RESUMO

AIMS: Current treatments of prosthetic joint infection (PJI) are minimally effective against Staphylococcus aureus biofilm. A murine PJI model of debridement, antibiotics, and implant retention (DAIR) was used to test the hypothesis that PlySs2, a bacteriophage-derived lysin, can target S. aureus biofilm and address the unique challenges presented in this periprosthetic environment. METHODS: The ability of PlySs2 and vancomycin to kill biofilm and colony-forming units (CFUs) on orthopaedic implants were compared using in vitro models. An in vivo murine PJI model of DAIR was used to assess the efficacy of a combination of PlySs2 and vancomycin on periprosthetic bacterial load. RESULTS: PlySs2 treatment reduced 99% more CFUs and 75% more biofilm compared with vancomycin in vitro. A combination of PlySs2 and vancomycin in vivo reduced the number of CFUs on the surface of implants by 92% and in the periprosthetic tissue by 88%. CONCLUSION: PlySs2 lysin was able to reduce biofilm, target planktonic bacteria, and work synergistically with vancomycin in our in vitro models. A combination of PlySs2 and vancomycin also reduced bacterial load in periprosthetic tissue and on the surface of implants in a murine model of DAIR treatment for established PJI. Cite this article: Bone Joint J 2020;102-B(7 Supple B):3-10.


Assuntos
Bacteriófagos , Enzimas/farmacologia , Infecções Relacionadas à Prótese/terapia , Infecções Estafilocócicas/terapia , Animais , Antibacterianos/farmacologia , Bacteriólise , Biofilmes , Contagem de Colônia Microbiana , Desbridamento , Modelos Animais de Doenças , Técnicas In Vitro , Camundongos Endogâmicos C57BL , Infecções Relacionadas à Prótese/microbiologia , Vancomicina/farmacologia
10.
Int J Food Microbiol ; 331: 108786, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32659617

RESUMO

Sweet orange essential oil is obtained from the peels of Citrus sinensis (CSEO) by cold pressing, and used as a valuable product by the food industry. Nanoencapsulation is known as a valid strategy to improve chemical stability, organoleptic properties, and delivery of EO-based products. In the present study we encapsulated CSEO using chitosan nanoemulsions (cn) as nanocarrier, and evaluated its antimicrobial activity in combination with mild heat, as well as its sensorial acceptability in orange and apple juices. CSEO composition was analyzed by GC-MS, and 19 components were identified, with limonene as the predominant constituent (95.1%). cn-CSEO was prepared under low shear conditions and characterized according to droplet size (<60 nm) and polydispersity index (<0.260 nm). Nanoemulsions were stable for at least 3 months at 4 ± 2 °C. cn-CSEO were compared with suspensions of CSEO (s-CSEO) (0.2 µL of CSEO/mL) in terms of antibacterial activity in combination with mild heat (52 °C) against Escherichia coli O157:H7 Sakai. cn-CSEO displayed a greater bactericidal activity than s-CSEO at pH 7.0 and pH 4.0. The validation in fruit juices showed an improved bactericidal effect of cn-CSEO in comparison with s-CSEO when combined with mild heat in apple juice, but not in orange juice. In both juices, the combination of CSEO and mild heat exerted synergistic lethal effects, reducing the treatment time to cause the inactivation of up to 5 Log10 cycles of E. coli O157:H7 Sakai cells. Finally, the sensory characteristics of both juices were acceptable either when using s-CSEO or CSEO nanoemulsified with chitosan. Therefore, as a promising carrier for lipophilic substances, the encapsulation of EOs with chitosan nanoemulsions might represent an advantageous alternative when combined with mild heat to preserve fruit juices.


Assuntos
Quitosana/química , Emulsões/farmacologia , Conservação de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Óleos Vegetais/química , Óleos Vegetais/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Bebidas/microbiologia , Quitosana/farmacologia , Citrus sinensis/química , Contagem de Colônia Microbiana , Emulsões/química , Escherichia coli O157/efeitos dos fármacos , Frutas/química , Temperatura Alta , Malus/microbiologia
11.
Artigo em Inglês | MEDLINE | ID: mdl-32664624

RESUMO

In recent years, the chaotic habits of modern life have favored the consumption of quickly prepared meals, using ready-to-eat (RTE) foods and condiments. The aim of this study was to establish the microbiological safety of RTE sauces and pesto from markets analyzed at different stages of shelf life. In the bacterial investigation, all samples were shown to be acceptable, although differences were observed concerning shelf life times. On the other hand, the fungal investigation showed frequent positive results, with concentrations higher than threshold values. Detected microbial diffusion was the lowest when products were far from the expiry date and had just been opened, while high microbial proliferation was observed when analyzing the same package after 48 h, higher than for a product close to the end of its shelf life. This study highlights the discreet microbiological quality of processed and RTE foods, underlining the importance of hygienic-sanitary surveillance of these foods to their shelf life. Consequently, it is necessary to: (1) implement a food control plan for all food categories to carry out risk analysis associated with their consumption; and (2) better adapt the regulations relating to microbiological analysis, and understand the biological significance of each microbial parameter throughout the shelf life of foods.


Assuntos
Qualidade de Produtos para o Consumidor , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Higiene , Contagem de Colônia Microbiana , Humanos , Listeria monocytogenes , Controle de Qualidade , Inquéritos e Questionários
12.
Sci Total Environ ; 745: 140795, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-32731065

RESUMO

BACKGROUND: Non-cholera Vibrio bacteria are a major cause of foodborne illness in the United States. Raw oysters are commonly implicated in gastroenteritis caused by pathogenic Vibrio parahaemolyticus. In response to outbreaks in 1997-1998, the US Food and Drug Administration developed a nation-wide quantitative microbial risk assessment (QMRA) of V. parahaemolyticus in raw oysters in 2005. The QMRA identified information gaps that new research may address. Incidence of sporadic V. parahaemolyticus illness has recently increased and, as oyster consumption increases and sea temperatures rise, V. parahaemolyticus outbreaks may become more frequent, posing health concerns. Updated and region-specific QMRAs will improve the accuracy and precision of risk of infection estimates. OBJECTIVES: We identify research to support an updated QMRA of V. parahaemolyticus from oysters harvested in Chesapeake Bay and Puget Sound, focusing on observational and experimental research on post-harvest practices (PHPs) published from 2004 to 2019. METHODS: A predefined search strategy was applied to PubMed, Embase, Scopus, Science.gov, NAL Agricola, and Google Scholar. Study eligibility criteria were defined using a population, intervention, comparator, and outcome statement. Reviewers independently coded abstracts for inclusion/exclusion using predefined criteria. Data were extracted and study quality and relevance evaluated based on published guidance for food safety risk assessments. Findings were synthesized using a weight of evidence approach. RESULTS: Of 12,174 articles retrieved, 93 were included for full-text review. Twenty-seven studies were found to be high quality and high relevance, including studies on cold storage, high hydrostatic pressure, depuration, and disinfectant, and other PHPs. High hydrostatic pressure consistently emerged as the most effective PHP in reducing abundance of V. parahaemolyticus. DISCUSSION: Limitations of the knowledge base and review approach involve the type and quantity of data reported. Future research should focus on PHPs for which few or no high quality and high relevance studies exist, such as irradiation and relaying.


Assuntos
Doenças Transmitidas por Alimentos/epidemiologia , Ostreidae , Vibrio parahaemolyticus , Animais , Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Inocuidade dos Alimentos , Alimentos Marinhos/análise
13.
Int J Food Microbiol ; 329: 108665, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32497789

RESUMO

Simultaneous treatment with 222-nm KrCl excilamp and mild heating (EX-MH) at 45, 50 and 55 °C showed synergistic bactericidal effects on non-acid and acid adapted cells of Escherichia coli O157:H7 and Salmonella Typhimurium in apple juice. In particular, acid-adapted pathogens exhibited increased resistance to EX-MH compared to pathogenic bacteria that were not acid-adapted. Also, elucidation of the synergistic bactericidal mechanism of EX-MH was performed through several assays and this mechanism was described as follows: (i) when KrCl excilamp (EX) and mild heating (MH) are applied simultaneously, MH reversibly inactivates the antioxidant enzyme, superoxide dismutase (SOD), thereby increasing accumulation of reactive oxygen species (ROS) generated by EX and thus inducing synergistic ROS generation, (ii) ROS production induces lipid peroxidation occurrence in the cell membrane, (iii) this lipid peroxidation occurrence in the cell membrane induces synergistic destruction of cell membrane, resulting in synergistic cell death. While EX-MH of 45, 50, or 55 °C reduced E. coli O157:H7 (the pathogen most resistant to EX-MH) in apple juice by 5-log, the qualities such as color (L*, a*, and b*), total phenolic compounds (TPC), and DPPH free radical scavenging activity of apple juice did not change significantly (P > 0.05). This study not only suggests the applicability of EX-MH to the apple juice industry, but also can be used as baseline data for future relevant research.


Assuntos
Antibacterianos/farmacologia , Escherichia coli O157/efeitos dos fármacos , Microbiologia de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Calefação , Viabilidade Microbiana , Salmonella typhimurium/efeitos dos fármacos , Bebidas/microbiologia , Cloro/farmacologia , Contagem de Colônia Microbiana , Criptônio/química , Criptônio/farmacologia , Malus/microbiologia
14.
Int J Food Microbiol ; 329: 108685, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32497791

RESUMO

Foodborne pathogens constitute a major food safety risk for cantaloupe, and pathogen biofilms formed are particularly difficult to remove. The goal of this study was to evaluate abrasive brushing in removing biofilms from cantaloupe surface using Listeria monocytogenes V7 and Salmonella enterica serovar Typhimurium ATCC 13311 as models. Cantaloupe rind pieces were inoculated and then subjected to 30 min or 24 h incubations. The incubated rind pieces were subject to different washing and/or brushing procedures and then the bacterial cells were enumerated. Cryo-SEM showed planktonic cells after 30 min incubation, whereas biofilms formed at rind surfaces after 24 h incubation. For L. monocytogenes 30 min incubation group, the log reductions were 1.4 for brushing, 2.1 for brushing with diatomaceous earth (DE), 2.8 for peroxyacetic acid (PAA) washing, 4.2 for brushing with PAA, and 4.0 for brushing with DE and PAA. In contrast, for the 24 h incubation group, the log reductions were 0.4 for brushing, 1.5 for brushing with DE, 1.1 for PAA washing, 1.6 for brushing with PAA, and 3.0 for brushing with DE and PAA. Similar results were observed for the S. Typhimurium group. These outcomes showed the pathogen-removal efficacy of brushing with DE (abrasive brushing) in the presence of biofilms, suggesting the potential application of abrasive brushing in cleaning cantaloupe for improved food safety.


Assuntos
Biofilmes , Cucumis melo/microbiologia , Manipulação de Alimentos/métodos , Microbiologia de Alimentos/métodos , Biofilmes/efeitos dos fármacos , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Listeria monocytogenes/efeitos dos fármacos , Ácido Peracético/farmacologia , Salmonella typhimurium/efeitos dos fármacos
15.
PLoS One ; 15(6): e0232869, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32579562

RESUMO

Automated colony counting methods have long been known in Microbiology. Numerous methods for automated image analysis have been described and a wide range of commercial products exists. Known advantages are saving cost by reducing enumeration time, automatic documentation, reproducibility, and operator independence. Still, even today the realization of all advantages of automated image analysis makes it necessary to either invest in an expensive, high performance commercial system, or to acquire expert knowledge in image processing. This is a considerable obstacle for many laboratories, and the reason why manual colony counting is still done frequently. This article describes an easy to apply automatic colony counting system-including suggestions for sample preparation-that can be put into operation with basic knowledge of image processing and low budget.


Assuntos
Automação Laboratorial/métodos , Contagem de Colônia Microbiana/métodos , Processamento de Imagem Assistida por Computador/métodos , Ágar , Automação Laboratorial/instrumentação , Contagem de Colônia Microbiana/instrumentação , Escherichia coli , Processamento de Imagem Assistida por Computador/instrumentação , Reconhecimento Automatizado de Padrão/métodos , Software
16.
PLoS One ; 15(6): e0233239, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32516315

RESUMO

Foodborne contamination and associated illness in the United States is responsible for an estimated 48 million cases per year. Increased food demand, global commerce of perishable foods, and the growing threat of antibiotic resistance are driving factors elevating concern for food safety. Foodborne illness is often associated with fresh-cut, ready-to-eat produce commodities due to the perishable nature of the product and relatively minimal processing from farm to the consumer. The research presented here optimizes and evaluates the utility of microfluidic droplets, also termed ultra-miniaturized bioreactors, for rapid detection of viable Salmonella enterica ser. Typhimurium in a shredded lettuce wash water acquired from a major Mid-Atlantic produce processing facility (denoted as Producer) in the U.S. Using a fluorescently-labeled anti-S. Typhimurium antibody and relative fluorescence intensities, paired with in-droplet incubation, S. Typhimurium was detected and identified with 100% specificity in less than 5 h. In initial optimization experiments using S. Typhimurium-spiked sterile water, the relative fluorescence intensity of S. Typhimurium was approximately two times that of the observed relative intensities of five non-S. Typhimurium negative controls at 4-h incubation in droplets containing Rappaport-Vasiliadis (RV) broth at 37°C: relative fluorescence intensity for S. Typhimurium = 2.36 (95% CI: 2.15-2.58), Enterobacter aerogens 1.12 (95% CI: 1.09-1.16), Escherichia coli 700609 = 1.13 (95% CI: 1.09-1.17), E. coli 13706 1.13 (95% CI: 1.07-1.19), E. coli 700891 1.05 (95% CI: 1.03-1.07) and Citrobacter freundii 1.04 (95% CI: 1.03-1.05). S. Typhimurium- and E. aerogens-spiked shredded lettuce wash waters acquired from the Producer were then incubated 4 h in-droplet at 37°C with RV broth. The observed relative fluorescence of S. Typhimurium was significantly higher than that of E. aerogens, 1.56 (95% CI: 1.42-1.71) and 1.10 (95% CI: 1.08-1.12), respectively. While further optimization focusing on compatible concentration methodologies for highly-dilute produce water samples is needed, this application of droplet microfluidics shows great promise in dramatically shortening the time necessary-from days to hours-to confirm viable bacterial contamination in ready-to-eat produce wash waters used throughout the domestic and international food industry.


Assuntos
Microbiologia de Alimentos/métodos , Doenças Transmitidas por Alimentos/prevenção & controle , Técnicas Analíticas Microfluídicas/métodos , Cloro/análise , Citrobacter freundii , Contagem de Colônia Microbiana , Desinfetantes , Escherichia coli O157 , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Indústria de Processamento de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Microfluídica/métodos , Salmonella typhimurium
17.
BMC Bioinformatics ; 21(1): 224, 2020 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-32493227

RESUMO

BACKGROUND: Currently the combination of molecular tools, imaging techniques and analysis software offer the possibility of studying gene activity through the use of fluorescent reporters and infer its distribution within complex biological three-dimensional structures. For example, the use of Confocal Scanning Laser Microscopy (CSLM) is a regularly-used approach to visually inspect the spatial distribution of a fluorescent signal. Although a plethora of generalist imaging software is available to analyze experimental pictures, the development of tailor-made software for every specific problem is still the most straightforward approach to perform the best possible image analysis. In this manuscript, we focused on developing a simple methodology to satisfy one particular need: automated processing and analysis of CSLM image stacks to generate 3D fluorescence profiles showing the average distribution detected in bacterial colonies grown in different experimental conditions for comparison purposes. RESULTS: The presented method processes batches of CSLM stacks containing three-dimensional images of an arbitrary number of colonies. Quasi-circular colonies are identified, filtered and projected onto a normalized orthogonal coordinate system, where a numerical interpolation is performed to obtain fluorescence values within a spatially fixed grid. A statistically representative three-dimensional fluorescent pattern is then generated from this data, allowing for standardized fluorescence analysis regardless of variability in colony size. The proposed methodology was evaluated by analyzing fluorescence from GFP expression subject to regulation by a stress-inducible promoter. CONCLUSIONS: This method provides a statistically reliable spatial distribution profile of fluorescence detected in analyzed samples, helping the researcher to establish general correlations between gene expression and spatial allocation under differential experimental regimes. The described methodology was coded into a MATLAB script and shared under an open source license to make it accessible to the whole community.


Assuntos
Pseudomonas putida/crescimento & desenvolvimento , Estatística como Assunto , Contagem de Colônia Microbiana , Fluorescência , Processamento de Imagem Assistida por Computador , Software
18.
Nat Commun ; 11(1): 3259, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32591509

RESUMO

Fusobacterium nucleatum is an oral anaerobe recently found to be prevalent in human colorectal cancer (CRC) where it is associated with poor treatment outcome. In mice, hematogenous F. nucleatum can colonize CRC tissue using its lectin Fap2, which attaches to tumor-displayed Gal-GalNAc. Here, we show that Gal-GalNAc levels increase as human breast cancer progresses, and that occurrence of F. nucleatum gDNA in breast cancer samples correlates with high Gal-GalNAc levels. We demonstrate Fap2-dependent binding of the bacterium to breast cancer samples, which is inhibited by GalNAc. Intravascularly inoculated Fap2-expressing F. nucleatum ATCC 23726 specifically colonize mice mammary tumors, whereas Fap2-deficient bacteria are impaired in tumor colonization. Inoculation with F. nucleatum suppresses accumulation of tumor infiltrating T cells and promotes tumor growth and metastatic progression, the latter two of which can be counteracted by antibiotic treatment. Thus, targeting F. nucleatum or Fap2 might be beneficial during treatment of breast cancer.


Assuntos
Neoplasias da Mama/microbiologia , Neoplasias da Mama/patologia , Progressão da Doença , Fusobacterium nucleatum/crescimento & desenvolvimento , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/imunologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Contagem de Colônia Microbiana , DNA Bacteriano/genética , Modelos Animais de Doenças , Feminino , Fusobacterium nucleatum/efeitos dos fármacos , Fusobacterium nucleatum/genética , Galactosamina/metabolismo , Galactose/metabolismo , Genoma Bacteriano/genética , Humanos , Imunidade/efeitos dos fármacos , Neoplasias Pulmonares/secundário , Camundongos Endogâmicos BALB C , Metástase Neoplásica
19.
Int J Food Microbiol ; 331: 108697, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32563133

RESUMO

This research investigated the use of high-pressure processing (HPP) for inactivating vegetative pathogens and spoilage microbiota in fresh unfiltered coconut water (Cocos nucifera L) from nuts obtained from Florida and frozen CW from Brazil with pH >5.0 and storage at 4 °C. Additionally, CW was evaluated to determine if it supported the growth and toxin production of Clostridium botulinum with or without the use of HPP when stored at refrigeration temperatures. Samples of fresh unfiltered CW were inoculated to 5.5 to 6.5 logs/mL with multiple strain cocktails of E. coli O157:H7, Salmonella spp. and Listeria monocytogenes and HPP at 593 MPa for 3 min at 4 °C. HPP and inoculated non-HPP controls were stored at 4 °C for 54 and 75 days for Florida CW and Brazil CW, respectively. Results of analyses showed HPP samples with <1 CFU/mL and no detection (negative/25 mL) with enrichment procedures for the 3 inoculated pathogens for all analyses. The non-HPP control samples did not show growth of the pathogens but a gradual decrease in levels to ca. 3-Logs/mL by day 54 in the fresh Florida CW and similarly in frozen Brazil CW by Day 75. Microbial spoilage of uninoculated samples was evaluated for normal spoilage microbiota through 120 days storage at 4 °C. Microbial counts remained at ca. 2-logs with no detectable signs of spoilage for HPP samples through 120 d. The non-HPP control samples spoiled within 2 weeks of storage at 4 °C with gas production, cloudiness, and off-odors. To evaluate if CW supports the growth and toxin production of C. botulinum, samples of unfiltered and filtered (0.2 µm) CW were inoculated with either proteolytic or non-proteolytic C. botulinum spores at 2 log CFU/mL that were processed at 593 MPa for 3 min and stored at 4 °C and 10 °C for 45 days. Inoculated positive and non-inoculated negative controls were prepared and stored as the HPP treated and non-HPP samples. No growth of C. botulinum or toxin production was detected in either the unfiltered or filtered CW regardless if products were HPP treated or not. All inoculated samples with C. botulinum spores were enriched at Day-45 in PYGS media to determine the viability of the inoculated spores at the end of shelf-life and screened for C. botulinum toxins. In all samples, C. botulinum toxin Types A, B and E were detected indicating spores were viable throughout the storage. Type F toxin was not detected possibly due to inherent conditions in the samples that may affected toxin screening.


Assuntos
Fenômenos Fisiológicos Bacterianos , Cocos/microbiologia , Manipulação de Alimentos/métodos , Microbiologia de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Alimentos Crus/microbiologia , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Brasil , Contagem de Colônia Microbiana , Temperatura
20.
Int J Food Microbiol ; 326: 108646, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32413802

RESUMO

The effects of using contaminated seed and water on the persistence and internalization of Salmonella Newport in organic spinach cultivars- Lazio, Space, Emilia and Waitiki were studied. Seeds were contaminated by either immersing in a suspension of Salmonella and then sprouted or were sprouted in Salmonella contaminated water in the dark at 25 °C. After 5 days, germinated sprouts were analyzed for S. Newport population and internalization. Germinated sprouts were potted in soil and grown in a plant incubator for 4 weeks. Leaves, stems and roots were sampled for Salmonella population by plating on CHROMagar™. Plants surface-sterilized with chlorine were analyzed for internalized pathogen. Potting soil and water runoff were sampled for Salmonella after 4 weeks of plant growth. Contaminated seeds and irrigation water had S. Newport populations of 7.64±0.43 log CFU/g and 7.12±0.04 log CFU/ml, respectively. Sprouts germinated using contaminated water or seeds had S. Newport populations of 8.09±0.04 and 8.08±0.03 log CFU/g, respectively and had a Salmonella population that was significantly higher than other spinach tissues (P<0.05). Populations of S. Newport in leaves, stem and roots of spinach plants were as follows: contaminated seed- 2.82±1.69, 1.69±0.86, and 4.41±0.62 log CFU/ml; contaminated water- 3.56±0.90, 3.04±0.31, and 4.03±0.42 log CFU/ml of macerated tissue suspension, respectively. Internalization was observed in plants developing from contaminated seeds and in sprouts germinated using contaminated water. S. Newport populations of 2.82±0.70 log CFU/g and 1.76±0.46 log CFU/ml were recovered from soil and water runoff, respectively. The results indicate that contamination of spinach during germination can result in persistence, internalization and environmental reintroduction of Salmonella.


Assuntos
Contaminação de Alimentos/análise , Folhas de Planta/microbiologia , Salmonella enterica/isolamento & purificação , Sementes/microbiologia , Spinacia oleracea/microbiologia , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Germinação , Raízes de Plantas/microbiologia , Sementes/crescimento & desenvolvimento , Microbiologia do Solo , Spinacia oleracea/crescimento & desenvolvimento
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