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1.
Shokuhin Eiseigaku Zasshi ; 60(4): 88-95, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31474656

RESUMO

Microbial colony counts of concern of food products are one of the most important items in microbiological examinations. The distributions of colony counts per agar plate of food samples are considered to be reflected with microbial cell distributions in food homogenates. However, (i) the probabilistic distributions of the colony counts per agar plate at the dilution of counting and (ii) the relationship between the colony counts per plate and the number of agar plates for food samples have not been intensively studied so far. In this study, therefore, these two points were studied with raw food samples of raw minced beef and chicken and raw milk and microbial culture samples of Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae. Among four major probabilistic distributions, it was found that aerobic plate counts per plate of the foods were well described with negative binomial, Poisson, and normal distributions and that the colony counts per plate of microbial cultures were described well with binomial, Poisson, and normal distributions. The effect of the number of agar plates on the estimation of the mean of colony counts per plate of a sample was then studied with the data randomly resampled from the experimental data. The resampled data showed that with more number of plates the mean of counts fluctuated less and the coefficients of variation of colony counts per plate decreased further, which were coincident to the estimated by the central limit theory. Our study would provide useful information on the characteristics of colony counts per plate of food samples which are routinely examined.


Assuntos
Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Ágar , Animais , Bovinos , Escherichia coli/isolamento & purificação , Carne/microbiologia , Leite/microbiologia , Saccharomyces cerevisiae/isolamento & purificação , Staphylococcus aureus/isolamento & purificação
2.
Vet Immunol Immunopathol ; 214: 109890, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31378218

RESUMO

Bovine mastitis is a significant cause of economic losses in the dairy industry. Staphylococcus aureus is one of the most common contagious mastitis pathogens, whereas Staphylococcus chromogenes increasingly became a significant cause of subclinical mastitis in dairy cows. Current mastitis control measures are not effective on all mastitis pathogens. There is no effective vaccine to control Staphylococcal mastitis in dairy cows. The objective of this study was to evaluate the immune responses and protection in dairy cows vaccinated with S. aureus surface proteins (SASP) or S. chromogenes surface proteins (SCSP). We divided eighteen Holstein dairy cows randomly into three groups of 6 animals each. We vaccinated group 1 and 2 animals with SASP and SCSP with Emulsigen-D adjuvant, respectively. We injected control (group 3) animals with PBS (pH 7.2) in Emulsigen®-D. We vaccinated animals three times at 28 and 14 days before drying off, and at dry off. Two weeks after the third vaccination, we challenged each animal by dipping all teats in S. aureus culture suspension once daily for 14 consecutive days. We evaluated milk or mammary secretion and serum antibody titers during vaccination and challenge periods. We evaluated milk samples for the number of bacteria shedding and somatic cell counts (SCC). Out of six cows vaccinated with SASP, one cow was removed from the study due to injury, two were infected clinically, another two were infected subclinically, and the remaining cow was not infected. No SCSP vaccinated cows developed clinical or subclinical mastitis. Out of six control cows, two developed clinical mastitis whereas four were infected subclinically. The SCSP vaccine cross-protected against S. aureus mastitis and reduced number of S. aureus shedding in milk. We concluded that the SCSP is a promising vaccine to control Staphylococcal mastitis in dairy cows.


Assuntos
Mastite Bovina/prevenção & controle , Proteínas de Membrana/imunologia , Infecções Estafilocócicas/veterinária , Vacinas Antiestafilocócicas/imunologia , Staphylococcus aureus/imunologia , Animais , Derrame de Bactérias , Bovinos , Contagem de Células , Indústria de Laticínios , Feminino , Proteínas de Membrana/administração & dosagem , Leite/microbiologia , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/prevenção & controle , Vacinação
4.
Niger J Clin Pract ; 22(8): 1083-1090, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31417051

RESUMO

Aims: The aim of this study was to provide epidemiological data about the presence of Salmonella spp. and Shigella spp. in raw milk samples collected from different animals. Methods: A total of 231 raw milk samples from 48 cows, 65 goats, 65 sheep, and 53 donkeys were studied. The ISO 6579:2002 and ISO 21567:2004 methods, antimicrobial susceptibility tests, and serotyping were performed. Species and subspecies discriminations were made via matrix-assisted laser desorption/ionization-time of flight mass spectrometry. After DNA isolation from all samples, Salmonella spp. and Shigella spp. were detected using real-time polymerase chain reaction (PCR) kits. Results: Five samples (2.16%) showed positivity out of 231 raw milk samples for Salmonella spp., and 2 (0.87%) samples were detected to be positive by multiplex real-time PCR design. Conclusion: We found that raw milk samples were not free of Salmonella spp. and Shigella spp. and need to be tested routinely to avoid public health problems. Rapid and reliable real-time PCR method can be developed and used for this purposes instead of slow bacterial culture processes.


Assuntos
DNA Bacteriano/análise , Contaminação de Alimentos/análise , Leite/microbiologia , Reação em Cadeia da Polimerase/métodos , Salmonella/genética , Salmonella/isolamento & purificação , Shigella/genética , Shigella/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Animais , Bovinos , Equidae , Feminino , Cabras , Humanos , Salmonella/classificação , Sensibilidade e Especificidade , Ovinos , Shigella/classificação
5.
Medicine (Baltimore) ; 98(35): e16601, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31464895

RESUMO

BACKGROUND: Lactobacillus paracasei and Glycyrrhiza glabra have been reported as having beneficial effects on Helicobacter pylori infection. We aimed to assess the efficacy and safety of fermented milk containing L paracasei HP7 and G glabra in patients with H pylori infection. METHODS: This multicenter, prospective, randomized, double-blind, placebo-controlled clinical trial was conducted in 2 hospitals from April to December 2017. Patients with H pylori infection were randomized into either the treatment group (fermented milk with L paracasei HP7 and G glabra) or placebo group (fermented milk only) once daily for 8 weeks. The primary endpoint was the gastric load of H pylori measured by C-urea breath test (UBT). Secondary endpoints were histologic and clinical improvement. RESULTS: A total of 142 patients were randomly allocated to the treatment (n = 71) or placebo groups (n = 71). Compared to baseline data, the quantitative value of C-UBT at 8 weeks was significantly reduced in the treatment group (from 20.8 ±â€Š13.2% to 16.9 ±â€Š10.8%, P = .035), but not in the placebo group (P = .130). Chronic inflammation improved significantly only in the treatment group (P = .013), whereas the neutrophil activity deteriorated significantly only in the placebo group (P = .003). Moreover, the treatment group had significant improvement in gastrointestinal symptoms (P = .049) and quality of life (P = .029). No serious adverse events were observed. CONCLUSION: The combination of fermented milk containing L paracasei and G glabra reduced H pylori density and improved histologic inflammation. However, their mechanisms of action should be elucidated in further studies.


Assuntos
Glycyrrhiza/fisiologia , Infecções por Helicobacter/tratamento farmacológico , Lactobacillus paracasei/fisiologia , Leite/microbiologia , Probióticos/administração & dosagem , Adulto , Idoso , Animais , Testes Respiratórios , Método Duplo-Cego , Feminino , Fermentação , Infecções por Helicobacter/imunologia , Infecções por Helicobacter/psicologia , Humanos , Masculino , Pessoa de Meia-Idade , Probióticos/efeitos adversos , Estudos Prospectivos , Qualidade de Vida/psicologia , Resultado do Tratamento , Adulto Jovem
6.
J Agric Food Chem ; 67(33): 9390-9398, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31365249

RESUMO

Various pathogens may coexist in one sample; however, detection methods that rely on traditional selective culture media or immune agents designed specifically for a certain target are unsuitable for multiple targets. It is important to develop a simultaneous and sensitive detection method for multiple pathogens. Here, a multicolor and ultrasensitive enzyme-linked immunosorbent assay (ELISA) platform based on the fluorescence hybridization chain reaction (HCR) was developed. In the assay, multicolor fluorescence concatemers formed as signal amplifiers and signal reporters in the presence of target pathogens. When HCR occurred, Escherichia coli O157:H7, Salmonella serotype Choleraesuis, and Listeria monocytogenes were detected simultaneously with three different fluorescences. Additionally, the limits of detection for E. coli O157:H7, Salmonella Choleraesuis, and L. monocytogenes were 3.4 × 101, 6.4 × 100, and 7.0 × 101 CFU/mL, respectively. The assay achieved ultrasensitive, specific, and simultaneous detection of three pathogens and can be applied to the detection of pathogens in milk samples. Therefore, this multicolor and ultrasensitive ELISA platform has great potential in the application of simultaneous detection of pathogens.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Escherichia coli O157/isolamento & purificação , Listeria monocytogenes/isolamento & purificação , Leite/microbiologia , Salmonella/isolamento & purificação , Animais , Bovinos , Ensaio de Imunoadsorção Enzimática/instrumentação , Fluorescência , Microbiologia de Alimentos , Sensibilidade e Especificidade
7.
Vet Microbiol ; 235: 71-79, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31282381

RESUMO

Streptococcus agalactiae (Group B streptococcus, GBS) is a commensal of the human intestinal tract and vagina and is also an opportunistic pathogen causing serious, potentially lethal, infections preferentially in newborns and in the elderly. In cattle, it is considered an udder-specific pathogen and a common cause of mastitis. Here we investigated the host specificity of GBS by examining their colonization at various anatomical sites in both cattle and humans, as well as the possible cross-species transmission in closed barn environments. We collected more than 800 swab samples from dairy cows and herdspersons at eight dairy farms in Denmark. GBS was isolated from 12% of the samples. The GBS strains (N = 105) were characterized by biochemical test, serology, and Pulsed-Field Gel Electrophoresis (PFGE). Based on the PFGE patterns, 25 strains were selected for whole genome sequencing followed by phylogenetic analyses. The genomes were compared to each other and to a collection of publicly available GBS genomes. The study revealed that GBS clones were shared by cows and herdspersons. In phylogenetic analyses, these shared clones clustered with GBS strains from persons with no relation to farming. Horizontal cross-species transmission of the contagion in both directions was found to be highly likely within the same environment; thus, some cases of bovine mastitis are probably antrophonotic.


Assuntos
Bovinos/microbiologia , Fazendeiros , Especificidade de Hospedeiro , Infecções Estreptocócicas/microbiologia , Streptococcus agalactiae/genética , Animais , Indústria de Laticínios , Dinamarca , Reservatórios de Doenças/microbiologia , Feminino , Humanos , Masculino , Mastite Bovina/microbiologia , Leite/microbiologia , Faringe/microbiologia , Filogenia , Reto/microbiologia , Infecções Estreptocócicas/transmissão , Streptococcus agalactiae/isolamento & purificação , Vagina/microbiologia
8.
Prev Vet Med ; 169: 104708, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31311635

RESUMO

Brucella spp. commonly infect humans in various regions worldwide. Human brucellosis mainly spreads through the consumption of contaminated raw dairy products and meat from domestic livestock (water buffalo, goats, sheep, cattle, pigs and camels). In this regard, the origin and routes of transmission of this bacterium should be carefully determined in order to control the source of infection. This study aimed to evaluate the rate of Brucella spp. contamination of camel milk samples sent for analysis to the national brucellosis laboratory during 2018 in Iran. For this purpose, 96 milk samples from 96 dairy camel herds were randomly collected from two provinces and investigated for the presence of Brucella spp contaminations by both bacterial culture method and polymerase chain reaction (PCR). No clinical manifestation of brucellosis was reported in camels from which milk samples were collected. Using the culture method, three milk samples (3%) originating from two camels of Isfahan province (4%) and one camel from the Semnan province (2%), were contaminated with Brucella abortus. According to PCR analyses, B. abortus gene was detected in 14 (14.5%) milk samples, including 9 and 5 samples from Isfahan (18%) and Semnan (11%) province, respectively. PCR method revealed significant differences (p = 0.02) in the level of contamination with B. abortus between milk samples collected from two regions. These results represent the first report regarding the isolation of B. abortus from raw camel milk in Iran and highlight the importance to screen apparent healthy camels. Therefore, the consumption of raw camel milk may contribute to the spread of human brucellosis in endemic regions.


Assuntos
Brucella abortus/isolamento & purificação , Camelus/microbiologia , Leite/microbiologia , Animais , Brucella abortus/genética , Brucelose/diagnóstico , Brucelose/epidemiologia , Brucelose/veterinária , Primers do DNA , Microbiologia de Alimentos , Irã (Geográfico)/epidemiologia , Reação em Cadeia da Polimerase/veterinária
9.
Int J Syst Evol Microbiol ; 69(9): 2862-2869, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31274399

RESUMO

Four Gram-stain positive, rod-shaped bacterial isolates, strains JZ R-183T, JZ RK-117, DI-46 and JZ R-35T, were recovered from bulk tank raw cow's milk from three different dairy farms in Germany. Analysis of their 16S rRNA gene sequences indicated that these isolates belonged to the family Micrococcaceae, closely related to the genera Arthrobacter, Neomicrococcus,Glutamicibacter and Citricoccus. The 16S rRNA gene sequence similarity between the isolates and the next related type strains was below 97.3 %. Phylogenetic analysis of 16S rRNA, recA and gyrB genes revealed that these isolates formed two different groups in an independent cluster within the family Micrococcaceae. Chemotaxonomic analyses determined anteiso-C15 : 0 as predominant fatty acid, but also large amounts of iso-C15 : 0, iso-C16 : 0 and iso-C17 : 0 were detected. The menaquinones MK-9(H2) and MK-7(H2) were present in all of the isolates and the polar lipid pattern contained the phospholipids diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol and a glycolipid. The peptidoglycan type of the isolates was A4α, with alanine, lysine and glutamate as dominating cell wall amino acids. The fatty acid and menaquinone profile differentiated the strains from the genera Arthrobacter, Neomicrococcus,Citricoccus and Glutamicibacter. The results of phylogenetic, phenotypic and chemotaxonomic analyses indicated that the isolates belonged to two novel species of a novel genus, for which the names Galactobacter caseinivorans gen. nov., sp. nov. and Galactobacter valiniphilus sp. nov. are proposed. The type strains are JZ R-183T (=DSM 107700T=LMG 30902T) and JZ R-35T (=DSM 107699T=LMG 30901T).


Assuntos
Micrococcaceae/classificação , Leite/microbiologia , Filogenia , Animais , Carga Bacteriana , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos/microbiologia , Parede Celular/química , DNA Bacteriano/genética , Ácidos Graxos/química , Feminino , Alemanha , Glicolipídeos/química , Micrococcaceae/isolamento & purificação , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
10.
J Photochem Photobiol B ; 197: 111554, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31326843

RESUMO

Bovine mastitis is an endemic disease of dairy cattle that is considered to be one of the most frequent and costly diseases in veterinary medicine. An increase in the incidence of disease results in the increased use of antibiotics, which in turn increases the potential of bacterial resistance. This study aimed to investigate the effectiveness of antimicrobial photodynamic therapy (aPDT) in the treatment of bovine mastitis, as an alternative to systemic antibiotics. To identify the key factors affecting photoinactivation efficacy, realistic experiments in view of the end-use were conducted in milk samples using two different photosensitizers: methylene blue (MB) and silicon (IV) phthalocyanine derivative (SiPc). We explored the effects of divalent ions and fat content on the aPDT outcome and determined influence of different proteins on aPDT efficacy. Levels of bacterial sensitivity to PSs varied depending on the type of bacteria (Gram-positive vs. Gram-negative) and light exposure time. Critical interrelated factors affecting aPDT in milk were identified and an efficient combination of treatment conditions that can lead to a full photodynamic inactivation of bacteria was determined.


Assuntos
Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Leite/microbiologia , Fármacos Fotossensibilizantes/farmacologia , Animais , Bovinos , Feminino , Indóis/química , Indóis/farmacologia , Indóis/uso terapêutico , Luz , Mastite Bovina/tratamento farmacológico , Mastite Bovina/microbiologia , Mastite Bovina/patologia , Azul de Metileno/farmacologia , Azul de Metileno/uso terapêutico , Proteínas do Leite/química , Fotoquimioterapia , Fármacos Fotossensibilizantes/uso terapêutico , Oxigênio Singlete/metabolismo
11.
Onderstepoort J Vet Res ; 86(1): e1-e9, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31291733

RESUMO

South Africa is a large country of approximately 1.22 million km2, made up of nine provinces with three climatic zones. Farming in the country is mostly defined by regional differences. Of the different organisms isolated from milk samples of dairy cows, Staphylococcus aureus poses a challenge to maintain udder health and wholesome dairy products for human consumption. Antibiotic resistant bacteria are therefore a potential health hazard. The objective of this study was to investigate the seasonal and regional relationships of antibiotic resistance of S. aureus, of which little is known. This study was undertaken to evaluate a data set of 3410 S. aureus isolates, taken from milk samples with a somatic cell count of > 400 000 cells/mL from commercial dairy herds. These isolates were tested for antimicrobial susceptibility using the Kirby Bauer method for ampicillin, cloxacillin, penicillin G, clindamycin, oxy-tetracycline, cephalexin, cefuroxime and tylosin. The samples were from 830 dairy herds, out of the estimated 2000 commercial dairy herds in South Africa. All the antibiotics tested, except for cephalosporins, showed a predicted prevalence of resistance of above 50% in most provinces, which is a concern. The lowest prevalence of resistance to the majority of the categories of antibiotics tested was present in KwaZulu-Natal during spring. The cephalosporins had the lowest levels of prevalence of bacterial resistance in Gauteng during winter. Resistance patterns of S. aureus to the eight antibiotics varied in the different seasons and provinces, possibly because of different weather conditions, and the action and spectrum of antibiotics.


Assuntos
Antibacterianos/farmacologia , Indústria de Laticínios , Mastite Bovina/epidemiologia , Leite/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/efeitos dos fármacos , Animais , Bovinos , Clima , Demografia , Farmacorresistência Bacteriana , Feminino , Mastite Bovina/microbiologia , Testes de Sensibilidade Microbiana/veterinária , Prevalência , África do Sul/epidemiologia , Infecções Estafilocócicas/epidemiologia
12.
J Agric Food Chem ; 67(32): 9104-9111, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31334655

RESUMO

Gold nanoflowers (GNFs) exhibit stronger light scattering ability than gold nanospheres (GNSs) with the same diameter, thereby contributing to enhancing the sensitivity of the scattering-based sensing method. However, the application of GNFs in biosensors based on dynamic light scattering (DLS) has not been yet reported. Herein, we describe for the first time an improved no-wash immunosensor based on dynamic light scattering for the detection of Escherichia coli O157:H7 (E. coli O157:H7) in milk using GNFs for sensitive signal transduction. To achieve this goal, a thiolated amphiphilic carboxyl ligand was introduced to modify the GNF surface and improve solution stability and antibody functionalization. Several key factors that affect the detection sensitivity of our developed GNF_DLS immunosensor were systematically investigated. Under the optimal conditions, our proposed GNF_DLS immunosensor provided an excellent linear detection for E. coli O157:H7 within the range from 6 × 100 to 6 × 104 colony-forming units (CFU)/mL, with a limit of detection of 2.7 CFU/mL. Combined with our previously reported two-step large-volume immunomagnetic separation (IMS) method, the designed GNF_DLS immunosensor can sensitively, selectively, and accurately detect the presence of E. coli O157:H7 in pasteurized milk. The potential of our GNF_DLS method for monitoring the presence of a single bacterial cell in 1 mL of sample solution was also demonstrated. Overall, the developed GNF_DLS immunosensor can be used for the rapid and high-sensitivity determination of pathogenic bacteria and can be extended for the ultrasensitive no-wash detection of other trace analytes.


Assuntos
Técnicas Biossensoriais/métodos , Difusão Dinâmica da Luz/métodos , Escherichia coli O157/isolamento & purificação , Leite/microbiologia , Animais , Técnicas Biossensoriais/instrumentação , Bovinos , Difusão Dinâmica da Luz/instrumentação , Escherichia coli O157/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Ouro/química , Leite/química , Nanoestruturas/química , Sensibilidade e Especificidade
13.
Vet Res ; 50(1): 44, 2019 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-31171032

RESUMO

The aim of this study was to analyze bacterial profiles of bovine mastitic milk samples and samples from healthy quarters using Next Generation Sequencing of amplicons from 16S rRNA genes and to compare results with microbiological results by PCR assays of the same samples. A total of 49 samples were collected from one single dairy herd during the same day. The samples were divided in two sample sets, which were used in this study. The DNA extraction as well as the library preparation and sequencing of these two sets were performed separately, and results of the two datasets were then compared. The vast majority of genera detected appeared with low read numbers and/or in only a few samples. Results of PCR and microbiome analyses of samples infected with major pathogens Staphylococcus aureus or Streptococcus uberis were consistent as these genera also covered the majority of reads detected in the microbiome analysis. Analysis of alpha diversity revealed a much higher species richness in set 1 than in set 2. The dominating bacterial genera with the highest read numbers clearly differed between datasets, especially in PCR negative samples and samples positive for minor pathogens. In addition to this, linear discriminant analysis (LDA) was conducted between the two sets to identify significantly different genera/family level microbes. The genus Methylobacterium was much more common in set 2 compared to set 1, and genus Streptococcus more common in set 1. Our results indicate amplification of contaminating bacteria in excess in samples with no or minor amounts of pathogen DNA in dataset 2. There is a need for critical assessment of results of milk microbiome analyses.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala/métodos , Microbiota , Leite/microbiologia , Reação em Cadeia da Polimerase/métodos , Animais , Bovinos , Feminino , Mastite Bovina/microbiologia , RNA Bacteriano/análise , RNA Ribossômico 16S/análise
14.
J Appl Microbiol ; 127(3): 683-692, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31216600

RESUMO

AIMS: The objective of this study was to compare qualitatively and quantitatively the results of identification of the bacteria present in milk samples from cows with subclinical mastitis using multiplex qPCR assay and matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS® ) after bacteriological growth. METHODS AND RESULTS: A total of 182 samples were aseptically collected from 119 cows with high somatic cell counts (>2·105 SCC per ml) on 11 farms in Belgium in 2014. The mutiplex qPCR assay was carried out on 350 µl of milk with the PathoProof® Complete-16kit. Ten microlitre of milk was streaked on Columbia blood agar and three selective agar plates. Growing colonies were identified by MALDI-TOF MS. Of the 182 samples, 90 gave positive results with either or both tests for one or two bacterial species/genera. Total qualitative agreement of the bacteria identified was observed in 41 mono- or bi-bacterial samples (46%) and partial agreement in 19 bi-bacterial samples at both or either tests (21%). The results of both tests on those mono- and bi-bacterial samples were not significantly different (McNemar test; P = 0·395) with a fair agreement (Cohen's kappa test; k = 0·375; P = 0·055). Moreover, quantitative correlation between the qPCR intensity and the numbers of growing colonies was observed in half of the 60 samples with qualitative matching results. CONCLUSIONS: Both methods give identical qualitative and quantitative results with approximately a half and a quarter of the mono- and bi-bacterial samples respectively. Several reasons can explain the differences. The multiplex qPCR assay only targets the most important mammary gland pathogens and can detect DNA of bacteria both alive and dead. Conversely, bacteria only grow when alive and the MALDI-TOF MS databases do not include all bovine milk-associated bacterial species yet. SIGNIFICANCE AND IMPACT OF THE STUDY: This study further highlights the limitations and complementarity of the genetic and phenotypic tests for the identification of bacteria present in milk samples.


Assuntos
Bactérias/isolamento & purificação , Mastite Bovina/microbiologia , Leite/microbiologia , Reação em Cadeia da Polimerase em Tempo Real , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Animais , Bactérias/genética , Bovinos , Feminino
15.
World J Microbiol Biotechnol ; 35(7): 102, 2019 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-31236715

RESUMO

Preparation of curd vary worldwide due to which its taste, texture and impact on human health also differ. In Assam, curd prepared from raw milk (RMC) is preferred over curd prepared from boiled milk (BMC), a tradition believed to have originated from the Mongoloid customs. Microbial diversity of raw milk (RM), boiled milk (BM), RMC and BMC collected from three farms were investigated by culture dependent and independent techniques. Additionally, metabolite profiles of RMC and BMC were studied by gas chromatography and mass spectroscopy. A total of 59 bacterial isolates were identified from the four different dairy products. In RM, lactic acid bacteria such as Lactococcus, Enterococcus, Lactobacillus and Leuconostoc were obtained along with the environmental bacteria like Bacillus, Staphylococcus, Acetobacter, Chryseobacterium, Streptococcus, Acinetobacter, Kocuria, Klebsiella and Macrococcus. Additionally, Prevotella, Oscillospira, Phascolarctobacterium and Akkermansia were also detected in BM by culture independent technique. In RMC and BMC, Lactococcus, Leuconostoc and Lactobacillus were prevalent. RM and RMC shared Enterococcus, Lactococcus, Streptococcus and Acinetobacter as common bacterial genera. However, no bacterial genus was common in BM and BMC. The correlation analysis revealed that Lactobacillus was negatively correlated to other bacterial genera. Oligotyping analysis revealed that Lactobacillus brevis and L.fermentum were abundant in RMC and BMC, respectively. In metabolomic study, ascorbic acid, dodecanoic acid and hexadecanoic acid were found to be significantly higher in RMC. Presence of different types of probiotics in these curds samples opens a new avenue to understand their effects on human health.


Assuntos
Bactérias/isolamento & purificação , Biodiversidade , Fermentação , Leite/microbiologia , Animais , Bactérias/metabolismo , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Enterococcus/isolamento & purificação , Enterococcus/metabolismo , Manipulação de Alimentos , Microbiologia de Alimentos , Sequenciamento de Nucleotídeos em Larga Escala , Lactobacillales , Lactobacillus/isolamento & purificação , Lactobacillus/metabolismo , Lactococcus/isolamento & purificação , Lactococcus/metabolismo , Leuconostoc/isolamento & purificação , Leuconostoc/metabolismo , Metagenômica , Análise Multivariada , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/isolamento & purificação
16.
Food Chem ; 296: 23-28, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31202302

RESUMO

Cronobacter sakazakii and Salmonella spp. are foodborne pathogens associated with low moisture foods. An intense pulsed light (IPL) system is being developed as an alternative novel method to pasteurize powdered food. The aim of the study is to investigate the microorganism inactivation in different powdered foods and a variety of related variables using a vibratory-assisted IPL system. The results showed that C. sakazakii on non-fat dry milk (NFDM), wheat flour, and egg white powder were significantly inactivated by 5.27, 4.92, and 5.30 log10 CFU/g, respectively, after 3 or 4 passes of IPL treatments. For decontamination of E. faecium, 3-4 passes of IPL treatments reduced the E. faecium level on NFDM, wheat flour, and egg white by 3.67, 2.79, 2.74 log10 CFU/g, respectively. These results demonstrated that the enhanced microbiological inactivation can be achieved using this vibratory-assisted IPL system after multiple passes.


Assuntos
Cronobacter sakazakii/efeitos da radiação , Enterococcus faecium/efeitos da radiação , Farinha/microbiologia , Luz , Salmonella/efeitos da radiação , Animais , Cronobacter sakazakii/crescimento & desenvolvimento , Clara de Ovo/microbiologia , Enterococcus faecium/crescimento & desenvolvimento , Microbiologia de Alimentos , Leite/microbiologia , Pós/química , Salmonella/crescimento & desenvolvimento , Temperatura Ambiente
17.
Int J Food Microbiol ; 304: 39-48, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31154110

RESUMO

A novel and facile method is developed for rapid estimation of lactic acid bacterial concentration in fermented milk. Growth of bacteria in a liquid changes physicochemical property of the medium and its behavior at solid-liquid interface. Wettability determines characteristic of solid-liquid interface. Nano-rod, helical tetragonal and L-shaped morphologies were designed and fabricated. Hydrophobicity and zeta potential were measured for dried surfaces of 5 dairy bacterial strains. Relationship between microbial population and changes in solid-liquid interface was studied by wettability and surface free energy measurements. Due to hydrophobic surface property of conventional dairy strains, they strongly affect solid-liquid and liquid-vapor surface tensions when dispersed in a liquid, which are dependent on the bacterial concentration. Response surface methodology results showed that type and concentration of bacteria, droplet volume and solid-surface morphology affect wettability significantly. Higher hydrophobicity resulted in higher ∆θ (absolute value of the difference between the pure physiological saline and the bacterial suspension contact angles) dependence on the bacterial concentration. Probiotic bacteria concentration in fermented milk was estimated using the proposed method. A direct relationship was obtained between milk contact angle and bacterial concentration. Results show that this physical method can be applied for rapid estimation of bacterial concentration.


Assuntos
Carga Bacteriana/métodos , Produtos Fermentados do Leite/microbiologia , Lactobacillales/isolamento & purificação , Leite/microbiologia , Animais , Reatores Biológicos , Fermentação , Interações Hidrofóbicas e Hidrofílicas , Ácido Láctico/metabolismo , Probióticos/química , Propriedades de Superfície , Molhabilidade
18.
J Anim Sci ; 97(7): 2889-2900, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31136650

RESUMO

The importance of the microbiota in the gastrointestinal tract of animals is recognized as a critical player in host health. Recently, the significance of the mycobiome has been recognized, but culture-independent studies are limited, especially in swine. Weaning is a time of stress, dietary changes, and a predisposition to infections, making it a time point of interest to industry. In this pilot study, we sought to assess and characterize the mycobiome in the feces of swine from birth through the critical weaning transition to investigate the mycobiome population and its temporal dynamics in piglet feces. Cultured fecal samples demonstrate a significant increase in fungal burden following weaning that does not differ from adult levels, suggesting stable colonization. Culturable fungi were not found in any environmental samples tested, including water, food, sow milk or colostrum. To determine the fungal diversity present and to address the problem of unculturable fungi, we performed a pilot study utilizing ITS and 16S rRNA focused primers for high-throughput sequencing of fungal and bacterial species, respectively. Bacterial populations increase in diversity over the experimental timeline (days 1 to 35 postbirth), but the fungal populations do not demonstrate the same temporal trend. Following weaning, there is a dynamic shift in the feces to a Saccharomycetaceae-dominated population. The shift in fungal population was because of the dominance of Kazachstania slooffiae, a poorly characterized colonizer of animal gastrointestinal tracts. This study provides insights into the early colonization and subsequent establishment of fungi during the weaning transition in piglets. Future studies will investigate the effect of the mycobiome on piglet growth and health during the weaning transition.


Assuntos
Bactérias/classificação , Fungos/classificação , Microbioma Gastrointestinal , Micobioma , Suínos/microbiologia , Animais , Bactérias/genética , Colostro/microbiologia , Dieta/veterinária , Fezes/microbiologia , Feminino , Fungos/genética , Trato Gastrointestinal/microbiologia , Sequenciamento de Nucleotídeos em Larga Escala/veterinária , Leite/microbiologia , Projetos Piloto , Gravidez , RNA Ribossômico 16S/genética , Análise de Sequência de DNA/veterinária , Suínos/fisiologia , Desmame
19.
J Appl Microbiol ; 127(2): 406-417, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31077513

RESUMO

AIM: To primarily estimate the sensitivity (Se) and specificity (Sp) of the commercially available Mastit4 quantitative PCR (qPCR) assay and bacterial culture (BC) for diagnosis of intramammary infections (IMI) and teat apex colonization (TAC) with coagulase-negative staphylococci (CNS) at different cut-offs for qPCR cycle threshold values using Bayesian latent class analysis. A secondary objective was to evaluate two cut-offs of BC for diagnosis of IMI and TAC with CNS. METHODS AND RESULTS: We randomly selected 13-20 cows with subclinical mastitis from eight dairy herds. Teat skin samples and aseptically collected foremilk samples were collected from the right hindquarters (n = 149) for BC and qPCR analysis. The Se of qPCR was always higher than BCSe in diagnosis of IMI, however; the Sp of BC was higher than qPCRSp . BCSe and BCSp showed no substantial difference between the tested BC cut-offs. In contrast to IMI, estimates of BC and qPCR in diagnosing TAC were different. BCSe was higher than qPCRSe at all tested cut-offs, however; qPCRSp was higher than BCSp . CONCLUSION: The overall performance of qPCR is higher than BC in the diagnosis of IMI; however, the performance of BC is better than qPCR in diagnosis of TAC. The qPCR and BC are valid diagnostics for bovine IMI with CNS. However, for TAC, both techniques require further investigation to reduce the uncertainty of the true status of the quarter and teat skin. SIGNIFICANCE AND IMPACT OF THE STUDY: We reported, for the first time, the diagnostic performance of new mastitis technology (Mastit4 PCR) and culture for detection of CNS in milk and nonmilk samples in dairy herds with automatic milking systems. Our findings will improve the interpretation of the test results of culture and qPCR assay and subsequently, will strengthen the control of IMI with CNS in dairy cows.


Assuntos
Mastite Bovina/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real , Infecções Estafilocócicas/veterinária , Animais , Teorema de Bayes , Bovinos , Feminino , Glândulas Mamárias Animais/microbiologia , Mastite Bovina/microbiologia , Leite/microbiologia , Sensibilidade e Especificidade , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/microbiologia , Staphylococcus/isolamento & purificação
20.
Int J Food Microbiol ; 303: 42-45, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31132730

RESUMO

Q fever is a bacterial zoonosis caused by Coxiella burnetii whose main reservoir are small ruminants. Infected animals shed the bacteria into the environment through the products of abortion as well as through feces, urine, and milk. Susceptible people are mainly infected by the inhalation of contaminated aerosols, while food-borne infection is unclear. High prevalence of C. burnetii DNA in cheeses from cattle, sheep or goat has been reported, but studies on viability of C. burnetii in hard cheeses are scarce. In this study, 67 sheep handicraft hard cheeses of different geographic origins made with unpasteurized milk were analyzed for the presence of C. burnetii DNA. To investigate viability of C. burnetii in cheese, 5 cheeses were selected among the 20 that tested DNA positive. Presence of viable C. burnetii was demonstrated in one cheese by experimental inoculation in BALB/c mice and culture in Vero cells. To further investigate the effect of cheese ripening in C. burnetii viability, another 12 cheeses elaborated in the same farm and season, and ripened for between 2.0 and 10.1 months were investigated. Results showed presence of C. burnetii DNA in all of them and viable C. burnetii in 5, indicating that C. burnetii can remain viable after at least 8 months of ripening in hard cheeses made with unpasteurized milk under the acid pH (4.96-5.41) and low water activity (0.9065-0.9533) conditions observed.


Assuntos
Queijo/microbiologia , Coxiella burnetii/fisiologia , Microbiologia de Alimentos , Animais , Bovinos , Cercopithecus aethiops , Coxiella burnetii/genética , Feminino , Cabras/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Viabilidade Microbiana , Leite/microbiologia , Gravidez , Febre Q/microbiologia , Ovinos , Células Vero , Zoonoses/microbiologia
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