RESUMO
BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 pandemic. METHODS: In this study, the antiviral activity of a far-UVC (222 nm) microplasma flat lamp against SARS-CoV-2 was evaluated. RESULTS AND CONCLUSIONS: Immediate inactivation of up to 99.99% of the coronavirus was achieved with a dose of less than 8 mJ/cm2 and complete inactivation was observed by real-time RT-PCR; therefore, far-UVC (222 nm) is a promising candidate for the effective inactivation of SARS-CoV-2.
Assuntos
COVID-19 , SARS-CoV-2 , Antivirais/farmacologia , Desinfecção , Humanos , Inativação de VírusRESUMO
Porcine epidemic diarrhoea virus (PEDV) is one of the major pathogens causing acute enteritis, which is characterised by vomiting and watery diarrhoea and commonly leads to high rates of mortality and morbidity in suckling piglets. Chitosan has been regarded as a promising natural disinfectant. In this study, the disinfectant effect and mammalian-cell toxicity of chitosan were evaluated against PEDV using Vero cells. A 0.01% solution of chitosan was determined to be an effective disinfectant. In addition, no evidence of toxicity was observed during the cell toxicity test; on the contrary, chitosan promoted cell proliferation. In conclusion, chitosan is a promising candidate for an effective and safe disinfectant against PEDV as well as other coronaviruses.
Assuntos
Quitosana , Infecções por Coronavirus , Desinfetantes , Vírus da Diarreia Epidêmica Suína , Doenças dos Suínos , Animais , Quitosana/farmacologia , Chlorocebus aethiops , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/veterinária , Desinfetantes/toxicidade , Suínos , Doenças dos Suínos/prevenção & controle , Células VeroRESUMO
BACKGROUND: Antimicrobial resistance is becoming increasingly important in both human and veterinary medicine. According to the One Health concept, an important step is to monitor the resistance patterns of pathogenic bacteria. In this study, the antimicrobial susceptibility patterns and trends of bacteria isolated from stray cats, hospital-admitted cats, and veterinary staff in South Korea between 2017 and 2018 were investigated. RESULTS: The minimum inhibitory concentrations of different antibiotics for Staphylococcus spp., Enterobacteriaceae, and Enterococcus spp. were determined to establish representatives of different antibiotic classes relevant for treatment or surveillance. For Coagulase-positive and Coagulase-negative Staphylococci, resistance to fluoroquinolones was below 13%, but resistance to ampicillin and penicillin was high (20-88%). A total of 9.5, 12.1, and 40.3% of staphylococcal isolates from stray cats, hospital-admitted cats, and veterinary staff, respectively, were confirmed to be mecA positive. For Enterobacteriaceae, resistance to carbapenems, fluoroquinolones, and 3rd generation cephalosporins was low (0-11.1%). The Enterococcus spp. isolates showed no resistance to vancomycin. The antimicrobial resistance rates of the Staphylococcus spp. and Enterobacteriaceae isolates from stray cats were usually lower than those of isolates from hospital-admitted cats and veterinary staff, but the Enterococcus spp. isolates revealed the opposite. Thus, the antimicrobial resistance varied across bacterial species according to the source from which they were isolated. CONCLUSIONS: Resistance to critically important compounds were low. However, the presence of antimicrobial resistance in cat isolates is of both public health and animal health concern.
Assuntos
Antibacterianos/farmacologia , Gatos/microbiologia , Farmacorresistência Bacteriana , Técnicos em Manejo de Animais , Animais , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/isolamento & purificação , Enterococcus/efeitos dos fármacos , Enterococcus/isolamento & purificação , Humanos , Testes de Sensibilidade Microbiana , República da Coreia , Staphylococcus/efeitos dos fármacos , Staphylococcus/isolamento & purificação , Médicos VeterináriosRESUMO
Numerous studies have explored the cultivation of muscle cells using non-animal materials for cultivated meat production. Achieving muscle cell proliferation and alignment using 3D scaffolds made from plant-based materials remains challenging. This study introduces a technique to culture and align muscle cells using only plant-based materials, avoiding toxic chemical modifications. Zein-alginate fibers (ZA fibers) were fabricated by coating zein protein onto alginate fibers (A fibers). Zein's excellent cell compatibility and biodegradability enable high cell adhesion and proliferation rates, and the good ductility of the ZA fibers enable a high strain rate (>75%). We demonstrate mature and aligned myotube formation in ZA fibers, providing a simple way to align muscle cells using plant-based materials. Additionally, cultivated meat was constructed by assembling muscle, fat, and vessel fibers. This method holds promise for the future mass production of cultivated meat.
RESUMO
Cattle are a major reservoir for Shiga toxin-producing Escherichia coli O157 (STEC O157) and harbor multiple genetic subtypes that do not all associate with human disease. STEC O157 evolved from an E. coli O55:H7 progenitor; however, a lack of genome sequence has hindered investigations on the divergence of human- and/or cattle-associated subtypes. Our goals were to 1) identify nucleotide polymorphisms for STEC O157 genetic subtype detection, 2) determine the phylogeny of STEC O157 genetic subtypes using polymorphism-derived genotypes and a phage insertion typing system, and 3) compare polymorphism-derived genotypes identified in this study with pulsed field gel electrophoresis (PFGE), the current gold standard for evaluating STEC O157 diversity. Using 762 nucleotide polymorphisms that were originally identified through whole-genome sequencing of 189 STEC O157 human- and cattle-isolated strains, we genotyped a collection of 426 STEC O157 strains. Concatenated polymorphism alleles defined 175 genotypes that were tagged by a minimal set of 138 polymorphisms. Eight major lineages of STEC O157 were identified, of which cattle are a reservoir for seven. Two lineages regularly harbored by cattle accounted for the majority of human disease in this study, whereas another was rarely represented in humans and may have evolved toward reduced human virulence. Notably, cattle are not a known reservoir for E. coli O55:H7 or STEC O157:H(-) (the first lineage to diverge within the STEC O157 serogroup), which both cause human disease. This result calls into question how cattle may have originally acquired STEC O157. The polymorphism-derived genotypes identified in this study did not surpass PFGE diversity assessed by BlnI and XbaI digestions in a subset of 93 strains. However, our results show that they are highly effective in assessing the evolutionary relatedness of epidemiologically unrelated STEC O157 genetic subtypes, including those associated with the cattle reservoir and human disease.
Assuntos
Escherichia coli O157/genética , Escherichia coli O157/isolamento & purificação , Filogenia , Toxina Shiga/biossíntese , Alelos , Animais , Bovinos , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Evolução Molecular , Genótipo , Técnicas de Genotipagem , Humanos , Modelos Genéticos , Polimorfismo Genético , Reprodutibilidade dos TestesRESUMO
Escherichia coli O157:H7 is a zoonotic human pathogen for which cattle are an important reservoir host. Using both previously published and new sequencing data, a 48-locus single nucleotide polymorphism (SNP)-based typing panel was developed that redundantly identified 11 genogroups that span six of the eight lineages recently described for E. coli O157:H7 (J. L. Bono, T. P. Smith, J. E. Keen, G. P. Harhay, T. G. McDaneld, R. E. Mandrell, W. K. Jung, T. E. Besser, P. Gerner-Smidt, M. Bielaszewska, H. Karch, M. L. Clawson, Mol. Biol. Evol. 29:2047-2062, 2012) and additionally defined subgroups within four of those lineages. This assay was applied to 530 isolates from human and bovine sources. The SNP-based lineage groups were concordant with previously identified E. coli O157:H7 genotypes identified by other methods and were strongly associated with carriage of specific Stx genes. Two SNP lineages (Ia and Vb) were disproportionately represented among cattle isolates, and three others (IIa, Ib, and IIb) were disproportionately represented among human clinical isolates. This 48-plex SNP assay efficiently and economically identifies biologically relevant lineages within E. coli O157:H7.
Assuntos
Escherichia coli O157/classificação , Escherichia coli O157/isolamento & purificação , Genótipo , Polimorfismo de Nucleotídeo Único , Animais , Técnicas de Tipagem Bacteriana , Bovinos/microbiologia , Doenças dos Bovinos/microbiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli O157/genética , Genes Bacterianos , Humanos , Filogenia , Análise de Sequência de DNA , Toxina Shiga I/genéticaRESUMO
Slaughtering animals for meat pose several challenges, including environmental pollution and ethical concerns. Scaffold-based cell-cultivated meat has been proposed as a solution to these problems, however, the utilization of animal-derived materials for scaffolding or the high cost of production remains a significant challenge. Alginate is an ideal material for cell-cultivated meat scaffolds but has poor cell adhesion properties. To address this issue, we achieved 82 % cell adhesion coverage by controlling the specific structure generated during the ionic crosslinking process of alginate. Post 11 days of culture; we evaluated cell adhesion, differentiation, and aligned cell networks. The cell growth increased by 12.7 % compared to the initial seeding concentration. Finally, we created hybrid cell-cultivated meat by combining single-cell protein from mycelium and cell-cultivated meat. This is non-animal based, edible, cost-effective, and has a desirable texture by blending cell-cultivated meat with a meat analogue. In summary, the creation of improved alginate fibers can effectively tackle various obstacles encountered in the manufacturing of cell-cultivated meat. This includes enhancing cell adhesion, reducing costs, and streamlining the production procedure.
Assuntos
Alginatos , Carne , Animais , Adesão Celular , Ciclo Celular , Diferenciação CelularRESUMO
An optical process by which transmission wavelengths can be divided selectively by changing a resonance condition of surface plasmons (SPs) is demonstrated. When white light is incident to an SP resonance substrate with a dielectric grating, SP waves are excited at resonance and transmitted into the air via diffraction by a large-area grating pattern fabricated by nanoimprint lithography. While only a limited range of certain wavelengths is allowed to transmit, the peak transmission wavelength can be tuned continuously in the visible band. We also show that multiple wavelengths are transmitted into different directions simultaneously by using a wedge-shaped white light.
Assuntos
Lentes , Refratometria/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Cor , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Espalhamento de RadiaçãoRESUMO
Although subwavelength dielectric gratings can be employed to achieve a high sensitivity of the surface plasmon resonance (SPR) biosensor, the plasmonic interpretation verifying the resulting sensitivity improvement remains unclear. The aim of this study is to elucidate the effects of the grating's geometric parameters on the amplification of SPR responses and to understand the physical mechanisms associated with the enhancement. Our numerical results show that the proposed SPR substrate with a dielectric grating can provide a better sensitivity due to the combined effects of surface reaction area and field distribution at the binding region. An influence of adhesion layer on the sensor performance is also discussed. The obtained results will be promising in high-sensitivity plasmonic biosensing applications.
Assuntos
Cromo/química , Ressonância de Plasmônio de Superfície/métodos , Algoritmos , Desenho de Equipamento , Ouro/química , Nanopartículas Metálicas/química , Análise Numérica Assistida por Computador , Ressonância de Plasmônio de Superfície/instrumentaçãoRESUMO
The interest in cultured meat is increasing because of the problems with conventional livestock industry. Recently, many studies related to cultured meat have been conducted, but producing large-sized cultured meat remains a challenge. It is aimed to introduce 3D bioprinting for producing large cell aggregates for cultured meat production. A hydrogel scaffold is produced at the centimeter scale using a bioink consisting of photocrosslinkable materials for digital light processing-based (DLP) printing, which has high printing accuracy and can produce geometrically complex structures. The light exposure time for hydrogel photopolymerization by DLP bioprinting is optimized based on photorheometry and cell viability assays. Naturally immortalized bovine embryonic fibroblast cells transformed with MyoD and PPARγ2 instead of primary cells are used as the latter have difficulties in maintaining stemness and are associated with animal ethics issues. The cells are mixed into the hydrogel for printing. Myogenesis and adipogenesis are induced simply by changing the medium after printing. Scaffolds are obtained successfully with living cells and large microchannels. The cooked cultured meat maintains its size and shape upon cutting. The overall dimensions are 3.43 cm × 5.53 cm × 0.96 cm. This study provides proof-of-concept for producing 3D cultured meat using bioinks.
Assuntos
Bioimpressão , Bovinos , Animais , Bioimpressão/métodos , Adipogenia , Transdiferenciação Celular , Alicerces Teciduais/química , Impressão Tridimensional , Hidrogéis/química , Fibroblastos , Desenvolvimento Muscular , CarneRESUMO
The emergence of extended-spectrum cephalosporin (ESC)-resistant Gram-negative bacteria is of great concern in both human and veterinary medicine. The aim of this study was to investigate ESC-resistant bacterial isolates from companion animals in South Korea between 2017 and 2019. Isolates with ESC resistance genes, which were identified by PCR, were assessed for genetic relatedness by multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). In total, 91 ESC-resistant Escherichia coli, Klebsiella spp., Serratia spp., and Enterobacter cloacae isolates harbored the blaTEM gene. Among other ESC resistance genes, blaCTX-M-15, blaCIT, and blaCTX-M-55 were predominantly detected in E. coli isolates, whereas blaSHV and blaDHA were more frequently detected in Klebsiella pneumoniae isolates. In addition, all blaEBC-positive isolates were classified as E. cloacae. From the MLST results, blaCTX-M-9-carrying ST131, blaCIT-carrying ST405, and blaCTX-M-1-carrying ST3285 strains were dominant among E. coli isolates. ST273 and ST275 strains harboring blaSHV were frequently detected in K. pneumoniae isolates. Various sequence types were obtained in E. cloacae and Klebsiella oxytoca isolates. All isolates demonstrated unique PFGE profiles (<57-98% similarity) and were unlikely to be derived from a single clone. The present study reveals the presence and wide genetic distribution of ESC-resistant bacterial species in South Korean companion animals.
RESUMO
Hydrogel-based scaffolds have been widely used to fabricate artificial tissues capable of replacing tissues and organs. However, several challenges inherent in fabricating tissues of large size and complex morphology using such scaffolds while ensuring cell viability remain. To address this problem, we synthesized gelatin methacryloyl (GelMA) based bioink with cells for fabricating a scaffold with superior characteristics. The bioink was grafted onto a Z-stacking bioprinter that maintained the cells at physiological temperature during the printing process, without exerting any physical pressure on the cells. Various parameters, such as the bioink composition and light exposure time, were optimized. The printing accuracy of the scaffolds was evaluated using photorheological studies. The internal morphology of the scaffolds at different time points was analyzed using electron microscopy. The Z-stacked scaffolds were fabricated using high-speed printing, with the conditions optimized to achieve high model reproducibility. Stable adhesion and high proliferation of cells encapsulated within the scaffold were confirmed. We introduced various strategies to improve the accuracy and reproducibility of Z-stack GelMA bioprinting while ensuring that the scaffolds facilitated cell adhesion, encapsulation, and proliferation. Our results demonstrate the potential of the present method for various applications in tissue engineering.
RESUMO
Transferring antimicrobial-resistant bacteria from companion animals to human hosts has become increasingly common. Data regarding antimicrobial susceptibility could help veterinarians to select the most appropriate antibiotic treatment. However, standardized and ongoing surveys regarding antimicrobial resistance remain limited. In this study, we investigated the antimicrobial-susceptibility patterns and trends of bacteria isolated from stray dogs, hospital-admitted dogs, and veterinary staff in South Korea from 2018 to 2019. The minimum inhibitory concentrations of different antimicrobials for Staphylococcus spp., Enterobacterales, and Enterococcus spp. were determined to establish representatives of different antibiotic classes relevant for treatment or surveillance. For coagulase-positive and -negative Staphylococci, resistance to gentamicin was <27 %, while that to ampicillin and penicillin was high (33-80 %). The mecA-detection rates among staphylococcal isolates were 28.5 %, 42.6 %, and 32 % from stray dogs, hospital-admitted dogs, and veterinary staffs, respectively. For Enterobacterales, resistance to carbapenems was low (0-6%). A total of 31.2 % and 18.9 % of Enterobacterales isolates from stray dogs and hospital-admitted dogs were confirmed to possess at least one of blaCTX-M, blaSHV, or blaTEM. Additionally, Enterococcus spp. isolates showed no resistance to vancomycin. These results demonstrate that dogs are commonly colonized with antimicrobial-resistant bacteria and highlight the need for further investigation.
Assuntos
Zoonoses Bacterianas/epidemiologia , Doenças do Cão/epidemiologia , Resistência Microbiana a Medicamentos , Infecções por Bactérias Gram-Negativas/epidemiologia , Infecções por Bactérias Gram-Negativas/veterinária , Infecções por Bactérias Gram-Positivas/epidemiologia , Infecções por Bactérias Gram-Positivas/veterinária , Técnicos em Manejo de Animais/estatística & dados numéricos , Animais , Zoonoses Bacterianas/microbiologia , Doenças do Cão/microbiologia , Cães , Enterococcus/efeitos dos fármacos , Enterococcus/isolamento & purificação , Gammaproteobacteria/efeitos dos fármacos , Gammaproteobacteria/isolamento & purificação , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Incidência , Prevalência , República da Coreia/epidemiologia , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus/efeitos dos fármacos , Staphylococcus/isolamento & purificação , Médicos Veterinários/estatística & dados numéricosRESUMO
Equine respiratory disease is a common cause of poor performance and training interruptions. The higher incidence rate of infectious upper respiratory disease (IURD) in thoroughbred racehorses at the Seoul Race Park coincided with the frequent stabling season, shorter stabling periods, and younger ages in this study. Incidence rates were also correlated with significantly lower proportions of cells expressing MHC class II-, CD2 antigen-, CD4+- or CD8+-T lymphocyte-, and B lymphocyte in IURD patients compared with healthy control groups in the summer and fall and in 2-and-3-year-old groups. The data suggested that movement and new environments may have resulted in immunosuppression and inappropriate responses to respiratory pathogens in IURD patients. The IURD incidence decreased with age, perhaps by the acquisition of immunity, and study results suggested that immunologic protection was associated with IURD, particularly in young thoroughbred racehorses. Streptococci isolates were identified in 11 of 72 IURD horses, and 3 of these isolates were identified as Streptococcus. equi subsp. equi. S. equi subsp. zooepidemicus was isolated from 2 of 23 IURD horses in the spring (8.7%), 5 of 23 in the summer (21.7%), and 1 of 6 in winter (16.7%). S. equi subsp. zooepidemicus (5%) was also identified in 3 of 61 isolates from clinically normal horses. Racetracks should implement anti-IURD protective measures by assessing the capacity of equine immunologic protection at the Park and by limiting the introduction of specific respiratory pathogens (such as S. equi subsp. equi) by preventing the access of infected horses with a respiratory pathogen-free certification system prior to Park entry.
Assuntos
Doenças dos Cavalos/etiologia , Doenças dos Cavalos/microbiologia , Infecções Respiratórias/veterinária , Infecções Estreptocócicas/veterinária , Streptococcus equi/isolamento & purificação , Animais , Antibacterianos/uso terapêutico , Primers do DNA , Meio Ambiente , Predisposição Genética para Doença , Doenças dos Cavalos/tratamento farmacológico , Doenças dos Cavalos/imunologia , Cavalos , Coreia (Geográfico) , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase/métodos , Valores de Referência , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/etiologia , Infecções Respiratórias/imunologia , Infecções Estreptocócicas/tratamento farmacológico , Infecções Estreptocócicas/etiologia , Infecções Estreptocócicas/imunologia , Streptococcus equi/efeitos dos fármacos , Streptococcus equi/genéticaRESUMO
The antibacterial effect and mechanism of action of a silver ion solution that was electrically generated were investigated for Staphylococcus aureus and Escherichia coli by analyzing the growth, morphology, and ultrastructure of the bacterial cells following treatment with the silver ion solution. Bacteria were exposed to the silver ion solution for various lengths of time, and the antibacterial effect of the solution was tested using the conventional plate count method and flow cytometric (FC) analysis. Reductions of more than 5 log(10) CFU/ml of both S. aureus and E. coli bacteria were confirmed after 90 min of treatment with the silver ion solution. Significant reduction of S. aureus and E. coli cells was also observed by FC analysis; however, the reduction rate determined by FC analysis was less than that determined by the conventional plate count method. These differences may be attributed to the presence of bacteria in an active but nonculturable (ABNC) state after treatment with the silver ion solution. Transmission electron microscopy showed considerable changes in the bacterial cell membranes upon silver ion treatment, which might be the cause or consequence of cell death. In conclusion, the results of the present study suggest that silver ions may cause S. aureus and E. coli bacteria to reach an ABNC state and eventually die.
Assuntos
Antibacterianos/farmacologia , DNA Bacteriano/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Nitrato de Prata/farmacologia , Prata/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Membrana Celular/ultraestrutura , DNA Bacteriano/análise , Escherichia coli/química , Escherichia coli/ultraestrutura , Microscopia Eletrônica de Transmissão , Prata/análise , Staphylococcus aureus/fisiologiaRESUMO
Image contrast of whole bacteria was compared in Staphylococcus aureus and Escherichia coli depending on pre-stain suspension liquids by energy-filtering transmission electron microscopy. The two bacterial strains were suspended in three most commonly used liquids for negative staining (triple distilled water [DW], phosphate-buffered saline [PBS], and nutrient broth [NB]) and directly observed without staining or stained with neutralized potassium phosphotungstate (PTA), respectively. Even though in low contrast, unstained bacteria were observed owing to their inherent electron density and cell shape in zero-loss (elastic scattering) images. After being suspended in PBS, unstained bacteria appeared to have higher contrast and more refined periphery than DW-suspended ones, and extracellular appendage structures such as fimbriae and flagella could be discerned. The unstained bacteria appeared to be invariably surrounded with electron-lucent precipitates, possibly from PBS. As far as delineation of the structures, the combination of DW or PBS suspension with subsequent staining provided the most satisfactory results, as evidenced by high contrast of bacterial morphology and appendage structures. However, after being suspended in NB and stained with PTA, bacteria often had too high contrast or poor staining, with electrondense aggregates around the bacteria. These results suggest that suspension with concentrated organic aliquots including broth media before PTA staining could deteriorate image contrast, and should be used only in dilute form for visualizing bacterial morphology and appendage structures. moreover the contrast enhancement of unstained bacteria by salt granules would be advantageous in demonstrating bacterial sorption of environmental particles like heavy metals, maintaining minimal contrast for cell imaging.
Assuntos
Meios de Contraste/química , Escherichia coli/ultraestrutura , Microscopia Eletrônica de Transmissão por Filtração de Energia/métodos , Coloração Negativa/métodos , Ácido Fosfotúngstico/química , Staphylococcus aureus/ultraestrutura , Fímbrias Bacterianas/ultraestrutura , Flagelos/ultraestruturaRESUMO
A multiplex PCR assay that allows for the rapid screening of the 19 genes that encode staphylococcal enterotoxins (SEs) (sea to see, and seg to sei), SE-like (SEl) toxins (sej to ser, and seu), and toxic shock syndrome toxin-1 (TSST-1) (tst) was developed in this study. These toxins are included in the pyrogenic toxin superantigen (PTSAg) family and are responsible for many diseases such as staphylococcal food poisoning (SFP) and TSS. The primers were designed based on dual priming oligonucleotide (DPO) technology to detect all of the 19 SAg genes in three sets of PCR. The developed multiplex PCR was applied to 143 Staphylococcus aureus strains isolated from pork and chicken meat in Korea. Almost 50% of the strains possessed at least one of the 19 SAg genes. The most frequently found genes were seg, sei, sem, and sen (53 isolates, 37%), which were often found simultaneously in the same isolate. In those isolates, the seo (39 isolates, 27%) or seu (6 isolates, 4%) genes were frequently found together and this combination (seg, sei, sem, sen, and seo or seu) was considered to be a part of the enterotoxin gene cluster (egc). The sea gene (10 isolates, 7%) was the gene most frequently detected out of all the classical SE genes (sea to see). Although these classical SEs are considered to be major etiological factors in SFP, newly described SE or SEl genes (seg to ser, and seu) were more frequently detected than the classical SE genes in this study. There was no isolate detected containing the seb, sec, sek, sel, or seq genes. S. aureus possessing mobile genetic elements known to encode these SAg genes, such as egc, were presumed to be widely distributed among pork and chicken meats in Korea. The multiplex PCR developed in this study could be applied to the investigation of SAg genes in S. aureus strains isolated from various sources.
Assuntos
Contaminação de Alimentos/análise , Carne/microbiologia , Reação em Cadeia da Polimerase/métodos , Intoxicação Alimentar Estafilocócica/microbiologia , Staphylococcus aureus/imunologia , Superantígenos/genética , Animais , Sequência de Bases , Galinhas , Qualidade de Produtos para o Consumidor , Primers do DNA , DNA Bacteriano/genética , Enterotoxinas/genética , Enterotoxinas/isolamento & purificação , Humanos , Coreia (Geográfico) , Família Multigênica , Análise de Sequência de DNA , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Superantígenos/isolamento & purificação , SuínosRESUMO
Enterococci for which the minimum inhibitory concentration (MIC) of vancomycin was >/=8 mg/l were isolated from meat, feces, and raw milk samples collected in Korea from March to November 2003. Among the 243 vancomycin-resistant enterococci (VRE) that were identified the vanA vancomycin resistance gene was carried by 51 Enterococcus faecium and one Enterococcus sp., vanC1 was carried by 151 Enterococcus gallinarum, vanC2 was carried by 39 Enterococcus casseliflavus, and one Enterococcus sp. carried no van genes. Of the isolated enterococci carrying vanA, 4% were found to be highly resistant to gentamicin and 11% were resistant to ampicillin. Further genotyping of the E. faecium isolates carrying vanA using pulsed-field gel electrophoresis (PFGE) revealed extensive heterogeneity. The vancomycin resistance transferability test revealed that only two of the 52 enterococci carrying the vanA gene were able to transfer vancomycin resistance to other enterococci. The VRE were recovered from various animal sources with a particularly high prevalence of E. faecium carrying the vanA gene being found in poultry meat.
Assuntos
Enterococcus/efeitos dos fármacos , Enterococcus/isolamento & purificação , Resistência a Vancomicina , Animais , Proteínas de Bactérias , Carbono-Oxigênio Ligases , Bovinos/microbiologia , Galinhas/microbiologia , Qualidade de Produtos para o Consumidor , DNA Bacteriano/análise , Farmacorresistência Bacteriana Múltipla/genética , Eletroforese em Gel de Campo Pulsado , Fezes/microbiologia , Genótipo , Humanos , Coreia (Geográfico) , Carne/microbiologia , Testes de Sensibilidade Microbiana , Leite/microbiologia , Prevalência , Suínos/microbiologia , Resistência a Vancomicina/genéticaRESUMO
A total of 770 samples of retail raw meat were examined for the presence of Campylobacter spp. The samples were obtained randomly from 232 retail stores in Korea from September 2001 to April 2006. The highest contamination rates were observed in chicken meat (220 181.4%] of 270 samples), whereas the rates of contamination in pork and beef were extremely low (1.6 and 1.2%, respectively). The antibiotic-resistant patterns of the 317 Campylobacter isolates were examined by the agar dilution method. Resistance to doxycycline was the most common (97.5%), followed by ciprofloxacin (95.9%), nalidixic acid (94.6%), tetracycline (94.6%), enrofloxacin (84.2%), and erythromycin (13.6%). All Campylobacter isolates from the retail raw meat were resistant to at least one of the six antibiotics tested, and 296 isolates (93.4%) showed multidrug (four or more antibiotics) resistance. This demonstrates that the multidrug-resistant Campylobacter species are widespread in meats in Korea. Therefore, further investigations will be needed to determine appropriate methods for eliminating Campylobacter contamination in industrial chicken production and food chains.
Assuntos
Antibacterianos/farmacologia , Campylobacter/efeitos dos fármacos , Qualidade de Produtos para o Consumidor , Farmacorresistência Bacteriana , Contaminação de Alimentos/análise , Carne/microbiologia , Animais , Campylobacter/crescimento & desenvolvimento , Campylobacter/isolamento & purificação , Bovinos , Galinhas , Contagem de Colônia Microbiana , Farmacorresistência Bacteriana Múltipla , Humanos , Coreia (Geográfico) , Testes de Sensibilidade Microbiana , Prevalência , SuínosRESUMO
Campylobacter species are one of the most common causes of bacterial diarrhea in humans worldwide. The consumption of foods contaminated with two Campylobacter species, C. jejuni and C. coli, is usually associated with most of the infections in humans. In this study, a rapid, reliable, and sensitive multiplex real-time quantitative PCR was developed for the simultaneous detection, identification, and quantification of C. jejuni and C. coli. In addition, the developed method was applied to the 50 samples of raw chicken meat collected from retail stores in Korea. C. jejuni and C. coli were detected in 88 and 86% of the samples by real-time quantitative PCR and the conventional microbiological method, respectively. The specificity of the primer and probe sets was confirmed with 30 C. jejuni, 20 C. coli, and 35 strains of other microbial species. C. jejuni and C. coli could be detected with high specificity in less than 4 h, with a detection limit of 1 log CFU/ml by the developed real-time PCR. The average counts (log CFU per milliliter) of C. jejuni or C. coli obtained by the conventional methods and by the real-time PCR assay were statistically correlated with a correlation coefficient (R2) between 0.73 and 0.78. The real-time PCR assay developed in this study is useful for screening for the presence and simultaneous differential quantification of C. jejuni and C. coli.