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1.
N Engl J Med ; 382(7): 632-643, 2020 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-32053299

RESUMO

BACKGROUND: An outbreak of listeriosis was identified in South Africa in 2017. The source was unknown. METHODS: We conducted epidemiologic, trace-back, and environmental investigations and used whole-genome sequencing to type Listeria monocytogenes isolates. A case was defined as laboratory-confirmed L. monocytogenes infection during the period from June 11, 2017, to April 7, 2018. RESULTS: A total of 937 cases were identified, of which 465 (50%) were associated with pregnancy; 406 of the pregnancy-associated cases (87%) occurred in neonates. Of the 937 cases, 229 (24%) occurred in patients 15 to 49 years of age (excluding those who were pregnant). Among the patients in whom human immunodeficiency virus (HIV) status was known, 38% of those with pregnancy-associated cases (77 of 204) and 46% of the remaining patients (97 of 211) were infected with HIV. Among 728 patients with a known outcome, 193 (27%) died. Clinical isolates from 609 patients were sequenced, and 567 (93%) were identified as sequence type 6 (ST6). In a case-control analysis, patients with ST6 infections were more likely to have eaten polony (a ready-to-eat processed meat) than those with non-ST6 infections (odds ratio, 8.55; 95% confidence interval, 1.66 to 43.35). Polony and environmental samples also yielded ST6 isolates, which, together with the isolates from the patients, belonged to the same core-genome multilocus sequence typing cluster with no more than 4 allelic differences; these findings showed that polony produced at a single facility was the outbreak source. A recall of ready-to-eat processed meat products from this facility was associated with a rapid decline in the incidence of L. monocytogenes ST6 infections. CONCLUSIONS: This investigation showed that in a middle-income country with a high prevalence of HIV infection, L. monocytogenes caused disproportionate illness among pregnant girls and women and HIV-infected persons. Whole-genome sequencing facilitated the detection of the outbreak and guided the trace-back investigations that led to the identification of the source.


Assuntos
Surtos de Doenças , Doenças Transmitidas por Alimentos/epidemiologia , Listeria monocytogenes/isolamento & purificação , Listeriose/epidemiologia , Produtos da Carne/microbiologia , Adolescente , Adulto , Idoso , Técnicas de Tipagem Bacteriana , Estudos de Casos e Controles , Feminino , Doenças Transmitidas por Alimentos/etiologia , Doenças Transmitidas por Alimentos/mortalidade , Infecções por HIV/complicações , HIV-1 , Humanos , Recém-Nascido , Listeria monocytogenes/genética , Listeriose/etiologia , Listeriose/mortalidade , Masculino , Produtos da Carne/efeitos adversos , Pessoa de Meia-Idade , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , Recall e Retirada de Produto , Distribuição por Sexo , África do Sul/epidemiologia , Sequenciamento Completo do Genoma , Adulto Jovem
2.
Food Microbiol ; 87: 103367, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948615

RESUMO

Listeria monocytogenes is an important foodborne pathogen, causative agent of listeriosis. The epidemiology and persistence of this bacterium in meat processing plants may be related to its serotype, so it is of utmost importance to carry out a correct differentiation of L. monocytogenes serotypes. The objective of this study was to develop a unique quadruplex real-time quantitative PCR (qPCR) method able to differentiate the four most predominant and worrying L. monocytogenes serotypes (1/2a, 1/2b, 1/2c and 4b) in isolates from meat processing plants and ready-to-eat (RTE) dry-cured meat products. The design of specific primers and probes was based on the lmo0737, lmo0308, ORFC (locus genomically equivalent to gltA-gltB) and ORF2110 genes. A qPCR based on a fragment of the 16S rRNA gene was used to ensure the amplification of Listeria spp. genomic DNA. The standard curves showed efficiency values ranging between 92.3% and 105.8% and, R2 values > 0.98. The specificity of the method was also confirmed by the comparison of the results with those obtained by a previously reported conventional multiplex PCR. In addition, none of the strains which were not ascribed to L. monocytogenes amplified any of the target genes related to the four major serotypes of this pathogenic species. The qPCR, therefore, provides a sensitive, specific and rapid tool for identifying the L. monocytogenes serotypes 1/2a, 1/2b, 1/2c and 4b. This method could be very useful for identifying sources of L. monocytogenes contamination in the meat industry or for epidemiological monitoring of persistent strains throughout the processing of RTE meat products.


Assuntos
Listeria monocytogenes/isolamento & purificação , Carne/microbiologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Primers do DNA/genética , DNA Bacteriano/genética , Contaminação de Alimentos/análise , Manipulação de Alimentos/instrumentação , Listeria monocytogenes/classificação , Listeria monocytogenes/genética , Produtos da Carne/microbiologia , RNA Ribossômico 16S/genética , Sorogrupo
3.
Food Microbiol ; 87: 103385, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948626

RESUMO

The present work was carried out to evaluate the microbiological and physicochemical composition of salamis produced with the meat of beef, horse, wild boar and pork. Salami productions occurred under controlled laboratory conditions to exclude butchery environmental contaminations, without the addition of nitrate and nitrite. All trials were monitored during the ripening (13 °C and 90% relative humidity) extended until 45 d. The evolution of physicochemical parameters showed that beef and pork salamis were characterized by a higher content of branched chain fatty acids (FA) and rumenic acid than horse and wild boar salamis, whereas the last two productions showed higher values of secondary lipid oxidation. Plate counts showed that lactic acid bacteria (LAB), yeasts and coagulase-negative staphylococci (CNS) populations dominated the microbial community of all productions with Lactobacillus and Staphylococcus as most frequently isolated bacteria. The microbial diversity evaluated by MiSeq Illumina showed the presence of members of Gammaproteobacteria phylum, Moraxellaceae family, Acinetobacter, Pseudomonas, Carnobacterium and Enterococcus in all salamis. This study showed the natural evolution of indigenous fermented meat starter cultures and confirmed a higher suitability of horse and beef meat for nitrate/nitrite free salami production due to their hygienic quality at 30 d.


Assuntos
/microbiologia , Produtos da Carne/microbiologia , Animais , Bovinos , Fermentação , Microbiologia de Alimentos , Cavalos , Lactobacillales/genética , Lactobacillales/crescimento & desenvolvimento , Lactobacillales/isolamento & purificação , Produtos da Carne/análise , Carne Vermelha/microbiologia , Staphylococcus/genética , Staphylococcus/crescimento & desenvolvimento , Staphylococcus/isolamento & purificação , Sus scrofa , Suínos
4.
Meat Sci ; 159: 107919, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31472934

RESUMO

The effects of edible chitosan (CTS) coatings (0, 1, 2, and 3%) on Harbin red sausage storage stability at room temperature compared to vacuum packaging are discussed. The pH, moisture and L* of sausages decreased gradually, while the a*, TBARS, total aerobic bacteria (TAB) and lactic acid bacteria (LAB) increased significantly (P < 0.05) with the prolongation of storage time. In the same storage time, the storage stability was improved with the increase in the concentration of edible CTS coating, but there was no significant difference between 2% and 3% (P > 0.05). Although vacuum packaging can effectively maintain colour, moisture and reduce lipid oxidation, 2% CTS is outstanding in sustaining storage stability (pH and water distribution) and inhibition of microbial growth (TAB and LAB). In addition, no significant difference was observed between CTS coating and vacuum packaging on aroma and flavour (P > 0.05). In conclusion, CTS coating as edible packaging material can be used in meat products preservation.


Assuntos
Quitosana/química , Manipulação de Alimentos , Armazenamento de Alimentos , Produtos da Carne/análise , Temperatura Ambiente , Animais , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Peroxidação de Lipídeos , Produtos da Carne/microbiologia , Suínos , Fatores de Tempo , Água
5.
Meat Sci ; 159: 107917, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494521

RESUMO

In this study, effects of ingoing nitrite level (0, 50, 100 and 150 mg/kg), use of sodium ascorbate, addition of starter culture (Lactobacillus plantarum GM77 + Staphylococcus xylosus GM92) and cooking level (control, medium, medium well, well done and very well done) on nitrosamine formation in heat-treated sucuk, a type of semi-dry fermented sausage, were investigated. The use of ascorbate had no significant effect on NDMA (N-Nitrosodimethylamine) and NPIP (N-Nitrosopiperidine) contents in the presence of starter culture. A higher NPYR (N- Nitrosopyrrolidine) content was detected in the group with starter culture at 150 mg/kg nitrite level in comparison to the group without starter culture. Cooking level affected all identified nitrosamines very significantly. Ingoing nitrite level × cooking level interaction was only effective on NPIP and advanced cooking levels (well done and very well done) at higher ingoing nitrite levels (100 and 150 mg/kg) resulted in significant increases in NPIP content.


Assuntos
Ácido Ascórbico/química , Culinária , Dimetilnitrosamina/química , Produtos da Carne/análise , Nitritos/química , Animais , Bacteriocinas , Bovinos , Microbiologia de Alimentos , Temperatura Alta , Fosfatos de Inositol , Lactobacillus plantarum/metabolismo , Produtos da Carne/microbiologia , Carne Vermelha , Staphylococcus/metabolismo
6.
Meat Sci ; 159: 107936, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31518708

RESUMO

The substitution of dietary fiber and probiotic strains to reduce fat content of fermented sausages has been used for the development of innovative and healthier meat products. For this study, pork back fat was partially replaced by fructooligosaccharides (FOS) and the probiotic strains Lactobacillus paracasei and Lactobacillus rhamanosus. The fat replacement resulted in a significant decrease (P ≤ .05) in fat content (29%) compared with the control formulation (no fat substitution). The addition of FOS did not have a significant effect on microbial counts; however, reductions in Enterobacteriaceae and yeast were observed when Lactobacillus strains were also incorporated. The inclusion of FOS and probiotic strains did not show any significant effect on lipid oxidation and proteolysis. The partial fat replacement and the addition of Lactobacillus rhamanosus GG as probiotic strain in Spanish Salchichón can be considered a successful reformulation strategy for the meat product market.


Assuntos
Lactobacillus/fisiologia , Produtos da Carne/normas , Oligossacarídeos/química , Probióticos , Animais , Fermentação , Humanos , Peroxidação de Lipídeos , Produtos da Carne/análise , Produtos da Carne/microbiologia , Sensação , Suínos , Fatores de Tempo
7.
Food Microbiol ; 85: 103285, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500704

RESUMO

The objective of this study was to determine the kinetic parameters and apply Markov Chain Monte Carlo (MCMC) simulation to predict the growth of Clostridium perfringens from spores in cooked ground chicken meat during dynamic cooling. Inoculated samples were exposed to various cooling conditions to observe dynamic growth. A combination of 4 cooling profiles was used in one-step inverse analysis with the Baranyi model as the primary model and the cardinal parameters model as the secondary model. Six kinetic parameters of the Baranyi model and the cardinal parameters model, including Q0, Ymax, µopt, Tmin, Topt, and Tmax, were estimated. The estimated Tmin, Topt, and Tmax were 14.8, 42.9, and 50.5 °C, respectively, with a µopt of 5.25 h-1 and maximum cell density of 8.4 log CFU/g. Correlation analysis showed that both Q0 and Ymax are weakly correlated to other parameters, while the remaining parameters are mostly mildly to strongly correlated with each other. Although it may be difficult to estimate highly correlated parameters using a single temperature profile, one-step analysis with multiple different temperature profiles helped estimate them successfully. The estimated parameters were used as the prior information to construct the posterior distribution for Bayesian analysis. MCMC simulation was used to predict the bacterial growth using different dynamic temperature profiles for validation of the accuracy of the predictive models. The MCMC simulation results showed that the Bayesian analysis produced more accurate predictions of bacterial growth during cooling than the deterministic method. With Bayesian analysis, the root-mean-square-error (RMSE) of prediction was only 0.1 log CFU/g with all residual errors within ±0.25 log CFU/g. Therefore, Bayesian analysis is recommended for predicting the growth of C. perfringens in cooked meat during cooling.


Assuntos
Clostridium perfringens/crescimento & desenvolvimento , Culinária , Manipulação de Alimentos , Produtos da Carne/microbiologia , Temperatura Ambiente , Animais , Teorema de Bayes , Galinhas , Contagem de Colônia Microbiana , Simulação por Computador , Cinética , Cadeias de Markov , Modelos Biológicos , Método de Monte Carlo , Esporos Bacterianos/crescimento & desenvolvimento
8.
Food Microbiol ; 85: 103280, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31500706

RESUMO

Listeria monocytogenes causes severe diseases in humans, including febrile gastroenteritis and systemic infections that has a high mortality despite antibiotic treatment. This pathogen may cause massive outbreaks associated to the consumption of contaminated food products, which highlight its importance in public health. In the last decade, L. monocytogenes has emerged as a foodborne pathogen of major importance in Chile. A previous work showed that in Chile during 2008 and 2009, L. monocytogenes serotypes 1/2a, 1/2b and 4b were the most frequently identified in food and clinical strains. Here we report the molecular characterization of L. monocytogenes strains isolated from 2008 to 2017 in the country. Our results indicate that serotypes 1/2a, 1/2b and 4b continue to be the most commonly found in food products. In addition, we identify persistent and widespread PFGE subtypes. This study reports ten years of epidemiological surveillance ofL. monocytogenes in Chile.


Assuntos
Monitoramento Epidemiológico , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/epidemiologia , Listeria monocytogenes/genética , Listeriose/epidemiologia , Chile/epidemiologia , Contagem de Colônia Microbiana , DNA Bacteriano/genética , Surtos de Doenças , Doenças Transmitidas por Alimentos/microbiologia , Gastroenterite/epidemiologia , Gastroenterite/microbiologia , Variação Genética , Humanos , Listeria monocytogenes/patogenicidade , Produtos da Carne/microbiologia , Epidemiologia Molecular , Saúde Pública , Sorogrupo , Sorotipagem , Fatores de Virulência/genética
9.
Int J Food Microbiol ; 312: 108358, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31655356

RESUMO

Meat products are commonly regarded as one of the main sources of human listeriosis caused by Listeria monocytogenes. The objective of this study was to estimate the prevalence of L. monocytogenes in a range of meat products from 24 different Chinese regions by using meta-analysis of literature data and a novel sensitivity analysis approach. A total of 112 publications from five databases, published between 1 January 2007 and 31 December 2017, were systematically selected for relevance and covered meat products sampled between 2000 and 2016. Estimated by the random-effects model, the pooled prevalence of L. monocytogenes was 8.5% (95% CI: 7.1%-10.3%) in raw meats and 3.2% (95% CI: 2.7%-3.9%) in ready-to-eat (RTE) meats. The prevalence differed from high to low among raw meats including prefabricated raw meats 12.6% (95% CI: 6.9%-21.7%), fresh pork 11.4% (95% CI: 8.6%-14.9%), fresh beef 9.1% (95% CI: 6.3%-13.0%), fresh poultry 7.2% (95% CI:4.9%-10.4%), frozen raw meats 7.2% (95% CI: 5.7%-9.0%), and fresh mutton 5.4% (95% CI: 2.5%-11.0%). A higher L. monocytogenes prevalence level was shown in the meat products from central and northeastern China provincial regions. The entropy-based sensitivity analysis utilized in the meta-analysis indicated that the sampling period and location were two critical factors influencing the prevalence level of L. monocytogenes in meat products. A better understanding of differences in prevalence levels per geographic region and between meat product sources may allow the competent authorities, industry, and other relevant stakeholders to tailor their interventions to control the occurrence of L. monocytogenes in meat products effectively.


Assuntos
Contaminação de Alimentos/análise , Microbiologia de Alimentos , Listeria monocytogenes/isolamento & purificação , Produtos da Carne/microbiologia , Aves Domésticas/microbiologia , Animais , Bovinos , China , Humanos , Listeriose/epidemiologia , Prevalência , Ovinos , Suínos
10.
Int J Food Microbiol ; 313: 108379, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31675541

RESUMO

Lactobacillus algidus is a meat spoilage bacterium often dominating the bacterial communities on chilled, packaged meat. Yet, L. algidus strains are rarely recovered from meat, and only few studies have focused on this species. The main reason limiting detailed studies on L. algidus is related to its poor growth on the media routinely used for culturing food spoilage bacteria. Thus, our study sought to develop reliable culture media for L. algidus to enable its recovery from meat, and to allow subculturing and phenotypic analyses of the strains. We assessed the growth of meat-derived L. algidus strains on common culture media and their modifications, and explored the suitability of potential media for the recovery of L. algidus from meat. Moreover, we determined whether 12 meat-derived L. algidus strains selected from our culture collection produce biogenic amines that may compromise safety or quality of meat, and finally, sequenced de novo and annotated the genomes of two meat-derived L. algidus strains to uncover genes and metabolic pathways relevant for phenotypic traits observed. MRS agar supplemented with complex substances (peptone, meat and yeast extract, liver digest) supported the growth of L. algidus, and allowed the recovery of new L. algidus isolates from meat. However, most strains grew poorly on standard MRS agar and on general-purpose media. In MRS broth, most strains grew well but a subset of strains required supplementation of MRS broth with additional cysteine. Supplementation of MRS broth with catalase allowed growth in aerated cultures suggesting that the strains produced hydrogen peroxide when grown aerobically. The strains tested (n = 12) produced ornithine from arginine and putrescine from agmatine, and two strains produced tyramine from tyrosine. Our findings reveal that L. algidus populations are underestimated if routine culture protocols are applied, and prompt concerns that L. algidus may generate tyramine or putrescine in meat or fermented meat products.


Assuntos
Lactobacillus/crescimento & desenvolvimento , Produtos da Carne/microbiologia , Animais , Aminas Biogênicas/análise , Aminas Biogênicas/metabolismo , Bovinos , Meios de Cultura/metabolismo , Fermentação , Lactobacillus/metabolismo , Produtos da Carne/análise , Putrescina/análise , Putrescina/metabolismo , Suínos
11.
Meat Sci ; 160: 107960, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31669860

RESUMO

The effect of high pressure processing (HPP) on Listeria monocytogenes inactivation on the surface and in the interior of deboned dry-cured ham was investigated. Whole deboned hams were pressurized at 450 MPa for 10 min or 600 MPa for 5 min and stored for 60 d at 4 and 12 °C. In control non-pressurized dry-cured hams, L. monocytogenes counts decreased on the surface throughout refrigerated storage, whereas remained unchanged in the interior of the product. Treatments at 600 MPa reduced L. monocytogenes population by 2 logs on the surface and by 3 logs in the interior of hams. Minor changes in the physicochemical characteristics were found. High water activity in the interior of dry-cured ham might enhance the pathogen inhibition by HPP. Treatment at 600 MPa for 5 min in whole dry-cured ham allowed to reach the Food Safety Objective for L. monocytogenes according to the European and the USDA criteria in case of contamination during deboning.


Assuntos
Manipulação de Alimentos/métodos , Listeria monocytogenes/fisiologia , Produtos da Carne/microbiologia , Pressão , Animais , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Suínos
12.
Meat Sci ; 160: 107958, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31669862

RESUMO

This study focused on sarcoplasmic and myofibrillar protein degradation and the formation of peptides with antioxidant activity by mixed starters (Lactobacillus plantarum CD101 and Staphylococcus simulans NJ201). Gel electrophoresis indicated that the mixed starters can hydrolyze both sarcoplasmic and myofibrillar proteins, and the concentration of peptides increased (P < .05). Compared with the control group, using mixed starters led to a significant increase (P < .05) in the DPPH radical scavenging activity, Fe2+ chelating activity, and ABTS radical scavenging activity of sarcoplasmic proteins, but demonstrated no significant difference in myofibrillar proteins. Two hydrophobic fractions (C2, C5) separated by RP-HPLC in the inoculation groups with sarcoplasmic proteins showed high DPPH radical scavenging activity (66.60%, 60.50%). Eighteen peptides were identified by LC-MS/MS, which mainly arose from triosephosphate isomerase, creatine kinase M-type, and glyceraldehyde-3-phosphate dehydrogenase. Hydrophobic amino acids accounted for a large proportion. Our results indicate that mixed starters affect proteolytic characterization and contribute to the formation of peptides with antioxidant capacity in sarcoplasmic proteins.


Assuntos
Lactobacillus plantarum/metabolismo , Produtos da Carne/microbiologia , Proteólise , Staphylococcus/metabolismo , Animais , Antioxidantes/química , Fermentação , Proteínas Musculares/metabolismo , Miofibrilas/metabolismo , Peptídeos/metabolismo , Suínos
13.
Meat Sci ; 160: 107956, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31677433

RESUMO

The 3-methyl-butanal and 3-methyl-butanoic acid are known as fingerprint compounds from Staphylococcus aureus. In this study, we investigated production of these two volatile biomarkers and their correlation to S. aureus growth in pork. Both 3-methyl-butanal and 3-methyl-butanoic acid presented high specificity for S. aureus in either media or pork. In sterile minced pork and pork broth, production of volatile biomarkers and the growth of S. aureus were significantly correlated for most single cultures. However, for mixed cultures, only 3-methyl-butanoic acid indicated correlations with growth of S. aureus. Similar trending was also discovered in raw pork, where production of 3-methyl-butanoic acid was significantly correlated with the growth of S. aureus, but not for 3-methyl-butanal. In summary, 3-methyl-butanoic acid was a more stable metabolic marker than 3-methyl-butanal which could be used as an indicator for the presence of S. aureus in pork. This rapid, convenient and cost-effective detection approach could be applied in meat industry to achieve specific detection of S. aureus.


Assuntos
Aldeídos/metabolismo , Hemiterpenos/metabolismo , Ácidos Pentanoicos/metabolismo , Staphylococcus aureus/metabolismo , Animais , Biomarcadores/metabolismo , Microbiologia de Alimentos , Produtos da Carne/análise , Produtos da Carne/microbiologia , Staphylococcus aureus/crescimento & desenvolvimento , Suínos
14.
Syst Appl Microbiol ; 42(6): 126023, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31668878

RESUMO

Microbiota analysis of blown pack spoiled salami revealed five distinguishable Lactobacillus isolates we could not assign to a known species. Two of the isolates (TMW 1.2172T and TMW 1.1920) are rod-shaped, whilst three isolates (TMW 1.2098T, TMW 1.2118 and TMW 1.2188) appear coccus shaped or as short rods. All isolates are Gram-stain positive, facultative anaerobic, catalase and oxidase negative, non-motile and non-sporulating. Phylogenetic analysis of the 16S rRNA, dnaK, pheS and rpoA gene sequences revealed two distinct lineages within the genus Lactobacillus (L.). The isolates are members of the Lactobacillus alimentarius group with Lactobacillus ginsenosidimutans DSM 24154T (99.4% 16S similarity), Lactobacillus versmoldensis DSM 14857T (97.9%) and Lactobacillus furfuricola DSM 27174T (97.7%) as phylogenetic closest related species and L. alimentarius DSM 20249T (97.7%) and Lactobacillus paralimentarius DSM 13961T (97.5%) as closest relatives, respectively. Average Nucleotide Identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the isolates and their close related type strains are lower than 80% and 25%, respectively. For both designated type strains, the peptidoglycan type is A4α l-Lys-d-Asp and the major fatty acids are C16:0, C18:1ω9c and summed feature 7. Based on phylogenetic, phenotypic and chemotaxonomic analysis we demonstrated that the investigated isolates belong to two novel Lactobacillus species for which we propose the names Lactobacillus salsicarnum with the type strain TMW 1.2098T=DSM 109451T=LMG 31401Tand Lactobacillus halodurans with the type strain TMW 1.2172T=DSM 109452T=LMG 31402T.


Assuntos
/microbiologia , Microbiologia de Alimentos , Lactobacillus/classificação , Produtos da Carne/microbiologia , Filogenia , Animais , Composição de Bases , Ácidos Graxos/análise , Genes Bacterianos/genética , Genoma Bacteriano/genética , Lactobacillus/química , Lactobacillus/genética , Lactobacillus/ultraestrutura , Hibridização de Ácido Nucleico , Peptidoglicano/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da Espécie , Suínos
15.
Lett Appl Microbiol ; 69(6): 392-398, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31562639

RESUMO

Four cases of listeriosis in a hospital (A) in New Zealand were identified in 2012. Pulsed-field gel electrophoresis (PFGE) used at the time identified four pulsotypes amongst the clinical isolates. Two of the pulsotypes matched to Listeria monocytogenes isolates obtained from ready-to-eat (RTE) meat samples from a RTE producer tested during a nationwide microbiological survey the month prior. The outbreak investigation confirmed that the RTE producer had supplied product to the hospital and additional testing confirmed the presence of L.  monocytogenes in RTE meats from the hospital kitchen. Two further listeriosis cases presented in another hospital (B) with one clinical isolate identified as the same pulsotype as identified for one case in hospital A, but the epidemiology information concluded that the clinical cases from hospital B were not linked to the outbreak. Retrospective whole-genome sequencing confirmed that epidemiologically linked isolates belonging to three different genotypes for clinical cases from hospital A and RTE meats samples from the hospital kitchen differed by 0-1 core-genome locus or single nucleotide polymorphisms (SNP). The use of core-genome multilocus sequence typing and SNP analysis provided a greater degree of discrimination between isolates compared to PFGE. SIGNIFICANCE AND IMPACT OF THE STUDY: This study describes a listeriosis outbreak associated with a hospital in New Zealand and attributed to contaminated ready-to-eat (RTE) meat supplied to the hospital by a single producer. Retrospective whole-genome sequence analysis of outbreak isolates was found to provide a greater degree of discrimination between isolates compared to pulsed-field gel electrophoresis and supported the conclusions made at the time of the outbreak. The multiple genotypes identified from clinical cases and the RTE meats obtained during the outbreak highlight the importance of epidemiological concordance alongside genotyping.


Assuntos
Infecção Hospitalar/microbiologia , Listeria monocytogenes/genética , Listeriose/epidemiologia , Produtos da Carne/microbiologia , Carne/microbiologia , Surtos de Doenças , Eletroforese em Gel de Campo Pulsado , Microbiologia de Alimentos , Genoma Bacteriano/genética , Genótipo , Humanos , Listeria monocytogenes/classificação , Listeria monocytogenes/isolamento & purificação , Listeriose/microbiologia , Tipagem de Sequências Multilocus , Nova Zelândia/epidemiologia , Polimorfismo de Nucleotídeo Único/genética , Estudos Retrospectivos , Sequenciamento Completo do Genoma
16.
J Food Sci ; 84(10): 2932-2943, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31524954

RESUMO

The microbiota of traditional dry-cured sausages and industrial environment was assessed to characterize the diversity of coagulase-negative staphylococci (CNS), and establish potential relationships with hygiene level or technological characteristics. Eight processing units from South Portugal were audited according to a checklist of requirements. Environmental and products' samples at different production stages were evaluated regarding hygiene and safety criteria. CNS were recovered, characterized, and their potential use as starters evaluated. Low genetic diversity was observed for Staphylococcus xylosus, whereas Staphylococcus equorum showed diverse genetic profiles. Staphylococcus xylosus predominated in products with a long period of cold smoking, Staphylococcus saprophyticus in products with a long period of hot smoking, Staphylococcus epidermidis in products with a short period of cold smoking, and S. equorum in nonsmoked products. Most S. xylosus were resistant to tetracycline, whereas S. equorum were susceptible. Antibioresistance restricted the selection of starters due to safety recommendations. PRACTICAL APPLICATION: The present manuscript highlighted a few staphylococci strains that could potentially be used as starter cultures in fermented meat products. These selected strains do not show resistance to antimicrobials, exhibit adequate technological features, and are well adapted to the industrial environments of meat processing industries using different processing technologies. Therefore, the selected strains ready to be used in the manufacturing of traditional fermented meat products to ensure safety, standardize product properties, and shorten ripening.


Assuntos
Biodiversidade , Produtos da Carne/microbiologia , Staphylococcus/isolamento & purificação , Animais , Antibacterianos/farmacologia , Fermentação , Manipulação de Alimentos/instrumentação , Microbiologia de Alimentos , Filogenia , Portugal , Staphylococcus/classificação , Staphylococcus/efeitos dos fármacos , Staphylococcus/genética , Suínos
17.
J S Afr Vet Assoc ; 90(0): e1-e8, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31478731

RESUMO

Staphylococcus aureus, including methicillin-resistant strains, has been detected in food products of animal origin globally. Limited data have been reported on the factors contributing to antibiotic resistance of food-borne pathogens in South Africa. The primary aim of this study was to determine the prevalence of S. aureus, including antibiotic-resistant strains, in poultry meat products as well as the evaluation of potential risk factors for contamination of poultry meat products with antibiotic-resistant S. aureus isolates. A cross-sectional investigation was conducted in municipalities located across the nine provinces of South Africa, which included abattoirs, meat processing facilities, retail outlets and cold stores at the major ports of entry into South Africa. Staphylococcus aureus isolates obtained from various poultry meat products were tested for susceptibility to 14 antibiotic compounds representing 10 antibiotic classes using the Kirby-Bauer disc diffusion method. Potential risk factors were evaluated using a logistic regression model. Of the 311 samples tested, 34.1% (n = 106) were positive for S. aureus (95% confidence interval [CI], 28.9% - 39.7%). Seventy-two of the 106 isolates were randomly selected for antibiotic sensitivity testing. Twenty-one per cent (n = 15) of the isolates selected for sensitivity testing were methicillin-resistant strains (95% CI, 12.2% - 32.0%). Multi-drug resistance was detected in 22.2% (n = 16) of these isolates tested (95% CI, 13.3% - 33.6%). Origin of the product (p = 0.160), type of meat product (p = 0.962), type of facility (p = 0.115) and facility hygiene practices (p = 0.484) were not significantly associated with contamination of poultry meat products with methicillin-resistant strains. The study provides baseline data for further studies on antibiotic resistance risk assessments for food-borne pathogens, including S. aureus, which should guide the implementation plans of the South African National Antimicrobial Resistance Strategy Framework, 2017-2024.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Produtos da Carne/microbiologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Aves Domésticas , Staphylococcus aureus/efeitos dos fármacos , Animais , Estudos Transversais , Microbiologia de Alimentos , Testes de Sensibilidade Microbiana , Doenças das Aves Domésticas/tratamento farmacológico , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/microbiologia , Fatores de Risco , África do Sul/epidemiologia , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/isolamento & purificação
18.
Int J Food Microbiol ; 309: 108312, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31499265

RESUMO

The characteristics and quality of home-made dry cured sausages can be recognized and associated with the region of origin. The characteristics of this type of sausages result from the superficial mycobiota that spontaneously colonizes the products. The aim of this study was to identify the house mycobiota associated with home-made dry cured sausages from different localities of Argentina and characterize the populations of Penicillium nalgiovense present by morphological and biochemical markers. To this end, 79 samples were collected from 10 localities of three main producing regions (Buenos Aires, Córdoba and La Pampa provinces). A total of 196 isolates belonging to six genera and 17 species were obtained. The predominant genus was Penicillium (134 of the isolates) and the predominant species was P. nalgiovense (108 isolates). The isoenzyme patterns of α-esterase (α-EST; EC 3.1.1.1) and Malate dehydrogenase NADP+(MDHP; EC 1.1.1.40) were characterized in 48 of these isolates (ten from Colonia Caroya, ten from Oncativo, ten from Tandil, nine from Mercedes and nine from La Pampa). A total of 26 bands were observed: 17 for α-EST and 9 for MDHP. α-EST was the most polymorphic isoenzyme, whereas MDPH presented no polymorphism. The results were subjected to numerical analysis. Cluster analysis revealed the formation of two groups: Group I formed by 24 isolates from Córdoba and Buenos Aires provinces and Group II with 24 isolates from La Pampa and Buenos Aires province. These data suggest the existence of morphological and biochemical variations among P. nalgiovense populations with different geographical origin.


Assuntos
Produtos da Carne/microbiologia , Penicillium/classificação , Penicillium/isolamento & purificação , Argentina , Esterases/genética , Fermentação , Contaminação de Alimentos/análise , Malato Desidrogenase/genética , Penicillium/genética
19.
Can J Microbiol ; 65(12): 913-921, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31491332

RESUMO

This study reports the use of reverse transcription - loop-mediated isothermal amplification (RT-LAMP) to detect Listeria monocytogenes in meat. The assay was designed to target the iap gene of L. monocytogenes, to which four primers, recognizing six distinct iap sites, were designed. We optimized the RT-LAMP conditions and established the following optimal systems: 60 min, 63 °C, 2.0 mmol/L MgSO4, 1.0 mol/L betaine, 2.0 mmol/L dNTPs, 320 U/mL Bst DNA polymerase, 0.4 µmol/L outer primers, and 0.8 µmol/L inner primers. The RT-LAMP amplification products were identified by a visible white Mg2P2O7 precipitate or electrophoresis on a 2% agarose gel. RT-LAMP has a sensitivity of 7.3 × 101 CFU/mL, which is 2-fold higher than that of LAMP. When commercially available raw meat samples (including beef, pork, mutton, and rabbit) were analyzed simultaneously with RT-LAMP and the Chinese National Standard GB 4789.30-2016, their abilities to detect L. monocytogenes were the same. Samples containing L. monocytogenes killed by 15 psi at 121 °C for 15 min were used to confirm the specificity of RT-LAMP for live microorganisms. Thus, we used RT-LAMP to efficiently detect L. monocytogenes in meat products.


Assuntos
Microbiologia de Alimentos/métodos , Listeria monocytogenes/isolamento & purificação , Produtos da Carne/microbiologia , Técnicas de Amplificação de Ácido Nucleico , Animais , Proteínas de Bactérias/genética , Lipoproteínas/genética , Listeria monocytogenes/genética , Carne/microbiologia , Sensibilidade e Especificidade
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