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1.
Lett Appl Microbiol ; 76(1)2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36688752

RESUMO

The present study aimed to reveal the microbial (bacteria and yeast) composition of raw milk from dairy camel (n = 10), cow (n = 10) and goat (n = 10) in North-western Nigeria. High-throughput DNA metabarcoding was used to compare microbial compositions in raw milk among the three species. Although the three species had similar dominant bacterial (Firmicutes and Proteobacteria) and yeast (Ascomycota and Basidiomycota) phyla, their microbial compositions at the genus level were noticeably different. The top differentially abundant bacterial and yeast genera (percentage abundance) were Lactobacillus (36%), Streptococcus (34%), Enterococcus (12%), Kluyveromyces (28%), Saccharomyces (24%), and Candida (18%), respectively. Principal coordinate analysis based on unweighted UniFrac values revealed significant differences in the structure of bacterial communities and no differences in yeast communities in milk samples from the three species. This study provides insight into the rich and diverse bacterial and yeast communities in raw animal milk consumed in Nigeria, which could play beneficial roles or pose health threats to consumers. However, further research on the economic significance of the microbial community in animal milk consumed in Nigeria is required.


Assuntos
Bactérias , Leite , Animais , Feminino , Bovinos , Leite/microbiologia , Nigéria , Enterococcus , Streptococcus , Leveduras
2.
Lett Appl Microbiol ; 76(1)2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36688767

RESUMO

The functional food ingredients market has been growing due to the preferences for healthier, nutritional, environment-friendly, and convenience foods. Here, we evaluated the antimicrobial potential of the lyophilized cell-free supernatants of the two most promising oral probiotic strains Streptococcus salivarius M18 and S. salivarius K12 on Pseudomonas aeruginosa to be applied for safety purposes in the milk. We showed that the lyophilized culture supernatant of the strain M18 inhibited the pathogen growth in milk by about 75%, 70%, and 60% when incubated at 37°C, room temperature, and +4°C, respectively. The inhibition levels were about 50%, 30%, and 45% for the lyophilized K12 cell-free supernatant. Besides, the lyophilized culture supernatants of the oral probiotics, especially of S. salivarius M18, exhibited anti-cancer activities on colon cancer cells in vitro. Thus, the results of this manuscript suggest that the cell-free supernatants of the M18 and K12 strains are potential candidates, which merit more investigation for their applications, as biopreservatives in foods and beverages and as anti-cancer biotics for human health.


Assuntos
Probióticos , Streptococcus salivarius , Humanos , Animais , Streptococcus , Leite , Probióticos/farmacologia , Bebidas
3.
J Clin Microbiol ; 61(1): e0080222, 2023 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-36515506

RESUMO

Streptococcus mitis is a common oral commensal and an opportunistic pathogen that causes bacteremia and infective endocarditis; however, the species has received little attention compared to other pathogenic streptococcal species. Effective and easy-to-use molecular typing tools are essential for understanding bacterial population diversity and biology, but schemes specific for S. mitis are not currently available. We therefore developed a multilocus sequence typing (MLST) scheme and defined sequence clusters or lineages of S. mitis using a comprehensive global data set of 322 genomes (148 publicly available and 174 newly sequenced). We used internal 450-bp sequence fragments of seven housekeeping genes (accA, gki, hom, oppC, patB, rlmN, and tsf) to define the MLST scheme and derived the global S. mitis sequence clusters using the PopPUNK clustering algorithm. We identified an initial set of 259 sequence types (STs) and 258 global sequence clusters. The schemes showed high concordance (100%), capturing extensive S. mitis diversity with strains assigned to multiple unique STs and global sequence clusters. The tools also identified extensive within- and between-host S. mitis genetic diversity among isolates sampled from a cohort of healthy individuals, together with potential transmission events, supported by both phylogeny and pairwise single nucleotide polymorphism (SNP) distances. Our novel molecular typing and strain clustering schemes for S. mitis allow for the integration of new strain data, are electronically portable at the PubMLST database (https://pubmlst.org/smitis), and offer a standardized approach to understanding the population structure of S. mitis. These robust tools will enable new insights into the epidemiology of S. mitis colonization, disease and transmission.


Assuntos
Streptococcus mitis , Streptococcus , Humanos , Tipagem de Sequências Multilocus , Streptococcus mitis/genética , Streptococcus/genética , Análise por Conglomerados , Filogenia
4.
J Endod ; 49(2): 178-189, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36526107

RESUMO

INTRODUCTION: Apical periodontitis (AP) represents an inflammatory condition of peri-radicular tissues due to invasion and colonization of bacteria in the root canals. Primary apical periodontitis (PAP) is associated with untreated necrotic root canal and can be efficiently treated with endodontic treatment to remove bacteria. Persistent/secondary apical periodontitis (SAP) is a perpetual periapical lesion due to unsuccessfully treated root canals after an initial apparent healing of the tooth. The aim of the study was evaluating the microbial communities associated with root canals using Nanopore sequencing. METHODS: Seventeen samples from the root canals of 15 patients with AP were Polymerase Chain Reaction-amplified for 16s ribosomal DNA gene and sequenced. Information regarding the presence or absence of AP symptoms, PAP and SAP, and periapical index of patients were recorded. RESULTS: Firmicutes, Bacteroidetes, and Actinobacteria were the most abundant phyla detected and Phocaeicola, Pseudomonas, Rothia, and Prevotella were the most prominent genera. In samples of patients with AP symptoms, the most frequent detected genera were Cutibacterium, Lactobacillus, Pseudomonas, Dialister, Prevotella, and Staphylococcus. In PAP samples, the most represented genera were Cutibacterium, Lactobacillus, Pseudomonas, and Prevotella, whilst in SAP cases were Cutibacterium, Prevotella, Atopobium, Capnocytophaga, Fusobacterium, Pseudomonas, Solobacterium, and Streptococcus. CONCLUSIONS: The results provide additional information on the microbiota of root-canals. These data evidence the complexity of the microbiota and the relationship with many clinical and endodontic conditions. Future studies must evaluate these conditions and identify their role in inducing bone damage and local and systemic disease, aiming to better elucidate the relationship between microbes and endodontic pathologies.


Assuntos
Actinobacteria , Microbiota , Periodontite Periapical , Humanos , Periodontite Periapical/microbiologia , Bactérias/genética , Tratamento do Canal Radicular/métodos , Microbiota/genética , Streptococcus , Cavidade Pulpar/microbiologia
5.
Pediatr Infect Dis J ; 42(1): e15-e17, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36476529

RESUMO

New studies of Group B Streptococcus (GBS) in infants <3 months of age in China have been published since our previous systematic review and meta-analysis. Using the same methodology, we updated these estimates and determined a total incidence of 0.41 (95% CI, 0.32-0.51) cases/1000 live births, lower than previously (0.55/1000). New intrapartum antibiotic prophylaxis policies may have played an important role in this reduction.


Assuntos
Políticas , Streptococcus , Humanos , China/epidemiologia
7.
Infect Genet Evol ; 107: 105398, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36572056

RESUMO

AIM: To determine Streptococcus agalactiae genes responsible for causing neonatal meningitis. BACKGROUND: Streptococcus agalactiae strain 2603 V/R is causative agent of neonatal meningitis, maternal infection and sepsis in young children. World health organisation reported high burden of new born death caused by this bacterium. Streptococcus agalactiae colonizing epithelial cells of vagina and endothelial cells have high resistance to available antibiotic drugs which makes it essential to determine new drug targets. OBJECTIVES: To compare the genome of selected strain with the non-pathogenic strains of streptococcus and identify the virulent and antibiotic resistant genes for adaptation in host environment. METHOD: The whole genome of human pathogen Streptococcus agalactiae strain 2603 V/R was analysed and compared with Streptococcus dysgalactiae strains using visualization and annotation tools. Genomic islands, mobile genetic elements, virulent and resistant genes were studied. RESULTS: Genetically pathogenic strain is most similar to Streptococcus dysgalactiae subsp. equisimilis strain NCTC 7136. Comparative analysis revealed the importance of capsular polysaccharides and surface proteins responsible for avoiding immune system attachment to host epithelial cells and virulent behaviour. High number of genes coding for antibiotics resistance may provide a competitive advantage for survival of pathogenic Streptococcus agalactiae strain 2603 V/R in its niche. CONCLUSIONS: The comparative analysis of pathogenic strain Streptococcus agalactiae with non-pathogenic strains of Streptococcus dysgalactiae provided new insights in pathogenicity that could aid in recognization for new regions and genes for development of new drug development strategies considering presence of high number of resistance genes.


Assuntos
Células Endoteliais , Infecções Estreptocócicas , Recém-Nascido , Feminino , Criança , Humanos , Pré-Escolar , Genoma Bacteriano , Infecções Estreptocócicas/microbiologia , Streptococcus/genética , Streptococcus agalactiae/genética , Antibacterianos/farmacologia
9.
Methods Mol Biol ; 2588: 201-216, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36418690

RESUMO

Selective markers employed in classical mutagenesis methods using natural genetic transformation can affect gene expression, risk phenotypic effects, and accumulate as unwanted genes during successive mutagenesis cycles. In this chapter, we present a protocol for markerless genome editing in Streptococcus mutans and Streptococcus pneumoniae achieved with an efficient method for natural transformation. High yields of transformants are obtained by combining the unimodal state of competence developed after treatment of S. mutans with sigX-inducing peptide pheromone (XIP) in a chemically defined medium (CDM) or of S. pneumoniae with the competence-stimulating peptide (CSP) together with use of a donor amplicon carrying extensive flanking homology. This combination ensures efficient and precise integration of a new allele by the recombination machinery present in competent cells.


Assuntos
Proteínas de Bactérias , Edição de Genes , Proteínas de Bactérias/metabolismo , Streptococcus/genética , Streptococcus/metabolismo , Streptococcus mutans/genética , Peptídeos/metabolismo
10.
Int Immunopharmacol ; 113(Pt A): 109413, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36461586

RESUMO

Excessive production of reactive oxygen species (ROS) leads to oxidative stress in host cells and affects the progress of disease. Mitochondria are an important source of ROS and their dysfunction is closely related to ROS production. S. uberis is a common causative agent of mastitis. The expression of key enzymes of the mitochondrial apoptotic pathway is increased in mammary epithelial cells after S. uberis stimulation, while expression of proteins related to mitochondrial function is decreased. Drp1, a key protein associated with mitochondrial function, is activated upon infection. Accompanied by mitochondria-cytosol translocation of Drp1, Fis1 expression is significantly upregulated while Mfn1 expression is downregulated implying that the balance of mitochondrial dynamics is disrupted. This leads to mitochondrial fragmentation, decreased mitochondrial membrane potential, higher levels of mROS and oxidative injury. The AMPK activator AICAR inhibits the increased phosphorylation of Drp1 and the translocation of Drp1 to mitochondria by salvaging mitochondrial function in an AMPK/Drp1 dependent manner, which has a similar effect to Drp1 inhibitor Mdivi-1. These data show that AMPK, as an upstream negative regulator of Drp1, ameliorates mitochondrial dysfunction induced by S. uberis infection.


Assuntos
Proteínas Quinases Ativadas por AMP , Streptococcus , Feminino , Humanos , Espécies Reativas de Oxigênio , Mitocôndrias
11.
BMC Microbiol ; 22(1): 313, 2022 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-36544085

RESUMO

BACKGROUND: Streptococcus agalactiae or group B Streptococcus (GBS) asymptomatically colonizes the genitourinary tracts of up to 30% of pregnant women. Globally, GBS is an important cause of neonatal morbidity and mortality. GBS has recently been linked to adverse pregnancy outcomes. The potential interactions between GBS and the vaginal microbiome composition remain poorly understood. In addition, little is known about the vaginal microbiota of pregnant Egyptian women. RESULTS: Using V3-V4 16S rRNA next-generation sequencing, we examined the vaginal microbiome in GBS culture-positive pregnant women (22) and GBS culture-negative pregnant women (22) during the third trimester in Ismailia, Egypt. According to the alpha-diversity indices, the vaginal microbiome of pregnant GBS culture-positive women was significantly more diverse and less homogenous. The composition of the vaginal microbiome differed significantly based on beta-diversity between GBS culture-positive and culture-negative women. The phylum Firmicutes and the family Lactobacillaceae were significantly more abundant in GBS-negative colonizers. In contrast, the phyla Actinobacteria, Tenericutes, and Proteobacteria and the families Bifidobacteriaceae, Mycoplasmataceae, Streptococcaceae, Corynebacteriaceae, Staphylococcaceae, and Peptostreptococcaceae were significantly more abundant in GBS culture-positive colonizers. On the genus and species levels, Lactobacillus was the only genus detected with significantly higher relative abundance in GBS culture-negative status (88%), and L. iners was the significantly most abundant species. Conversely, GBS-positive carriers exhibited a significant decrease in Lactobacillus abundance (56%). In GBS-positive colonizers, the relative abundance of the genera Ureaplasma, Gardnerella, Streptococcus, Corynebacterium, Staphylococcus, and Peptostreptococcus and the species Peptostreptococcus anaerobius was significantly higher. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to the metabolism of cofactors and vitamins, phosphatidylinositol signaling system, peroxisome, host immune system pathways, and host endocrine system were exclusively enriched among GBS culture-positive microbial communities. However, lipid metabolism KEGG pathways, nucleotide metabolism, xenobiotics biodegradation and metabolism, genetic information processing pathways associated with translation, replication, and repair, and human diseases (Staphylococcus aureus infection) were exclusively enriched in GBS culture-negative communities. CONCLUSIONS: Understanding how perturbations of the vaginal microbiome contribute to pregnancy complications may result in the development of alternative, targeted prevention strategies to prevent maternal GBS colonization. We hypothesized associations between inferred microbial function and GBS status that would need to be confirmed in larger cohorts.


Assuntos
Microbiota , Complicações Infecciosas na Gravidez , Infecções Estreptocócicas , Recém-Nascido , Feminino , Gravidez , Humanos , Gestantes , Terceiro Trimestre da Gravidez , Streptococcus agalactiae/genética , RNA Ribossômico 16S/genética , Infecções Estreptocócicas/microbiologia , Vagina/microbiologia , Streptococcus/genética , Complicações Infecciosas na Gravidez/microbiologia , Lactobacillus/genética , Microbiota/genética
12.
Int J Clin Pract ; 2022: 4752880, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36567774

RESUMO

Background: Pyogenic liver abscess (PLA) is an uncommon but potentially life-threatening condition. In recent years, advances in diagnostics and management have led to early diagnosis and treatment and decreased mortality. We present recent data from a large series of patients with PLA and examine the trends in the management of PLA over a period of 50 years. Methods: The medical records of all patients admitted to the Shaare Zedek Medical Center, Israel, between January 2011 and December 2021 with a primary or secondary diagnosis of PLA were reviewed retrospectively. Results: : Ninety-five patients with PLA were identified. Thirty-eight (40%) were female. The median patient age was 66 years (range 18-93). The diagnosis of PLA in all patients was confirmed with abdominal computed tomography (CT). In twenty patients (21.1%), PLA was not diagnosed by the initial abdominal US. Most abscesses were right-sided. Biliary tract origin was the most common underlying cause of PLA (n = 57, 60%), followed by cryptogenic etiology (n = 28, 30%). Escherichia coli, Klebsiella pneumoniae, and Streptococcus species were most commonly identified. The most common primary treatment modality was percutaneous drainage (PD), which was performed in 81 patients (85.3%). Fourteen patients (14.7%) were treated medically without intervention, and two patients (2.1%) were treated surgically following a failure of PD. Four patients died as a direct result of PLA. Conclusions: Patients diagnosed with PLA are older, the male predominance is less pronounced, and the offending pathogens are likely to originate from the biliary tract. This study questions the utility of abdominal US as the initial diagnostic imaging in patients with suspected PLA (versus CT) and demonstrates improved outcomes for patients with PLA over the years.


Assuntos
Infecções Bacterianas , Abscesso Hepático Piogênico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Causalidade , Escherichia coli/isolamento & purificação , Hospitalização , Abscesso Hepático Piogênico/diagnóstico , Abscesso Hepático Piogênico/epidemiologia , Abscesso Hepático Piogênico/terapia , Estudos Retrospectivos , Drenagem , Klebsiella pneumoniae/isolamento & purificação , Streptococcus/isolamento & purificação
13.
PeerJ ; 10: e14480, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36523462

RESUMO

Background: Sports mouthguards, worn in the oral cavity to prevent sports injuries, are constantly exposed to various microorganisms that cause oral infections. Hence, the optimal cleaning methods for sports mouthguards have been thoroughly examined. In this study, we evaluated the efficiency of cleaning effects with a mouthguard cleaner (MC) on microbial biofilm formation in sports mouthguards in vitro and in vivo. Methods: We evaluated the cleaning effects of the discs produced by ethylene-vinyl acetate (EVA) on bacterial biofilms formed by the commensal bacterium Streptococcus oralis, the cariogenic bacterium Streptococcus mutans, and the opportunistic pathogen Staphylococcus aureus in vitro. EVA discs with biofilm were subjected to sterile distilled water (CTRL) and ultrasonic washing (UW), followed by treatment with MC and sodium hypochlorite (NaClO) as positive controls. Thereafter, the viable bacterial cell counts were determined. The bacteria adhering to the sheets before and after the treatment were observed under an electron microscope. The degree of cleanliness and measurement of viable microbial cell counts for total bacteria, Streptococci and Candida, opportunistic fungi, were evaluated on the used experimental sports mouthguards with and without UW and MC treatment in vivo. Results: The number of bacterial cells significantly decreased against all the tested biofilm bacteria upon treatment with MC, compared with CTRL and UW. Electron microscopy analysis revealed the biofilm formation by all bacteria on the EVA discs before cleaning. We observed fewer bacteria on the EVA discs treated with MC than those treated with CTRL and UW. Furthermore, the degree of cleanliness of the used experimental sports mouthguards cleaned using MC was significantly higher than that of the CTRL-treated mouthguards. Moreover, the viable microbial cell counts on the used experimental sports mouthguard were considerably lower than those on the CTRL ones. Conclusion: The cleaning effect of MC against oral bacteria was more effective than that of UW. MC treatment might have a potential future application as a cleaning method for sports mouthguards to protect athletes from oral infection.


Assuntos
Esportes , Humanos , Compostos de Vinila , Streptococcus , Etilenos/farmacologia
14.
Int J Mol Sci ; 23(23)2022 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-36499130

RESUMO

Streptomyces coelicolor and Streptomyces lividans constitute model strains to study the regulation of antibiotics biosynthesis in Streptomyces species since these closely related strains possess the same pathways directing the biosynthesis of various antibiotics but only S. coelicolor produces them. To get a better understanding of the origin of the contrasted abilities of these strains to produce bioactive specialized metabolites, these strains were grown in conditions of phosphate limitation or proficiency and a comparative analysis of their transcriptional/regulatory proteins was carried out. The abundance of the vast majority of the 355 proteins detected greatly differed between these two strains and responded differently to phosphate availability. This study confirmed, consistently with previous studies, that S. coelicolor suffers from nitrogen stress. This stress likely triggers the degradation of the nitrogen-rich peptidoglycan cell wall in order to recycle nitrogen present in its constituents, resulting in cell wall stress. When an altered cell wall is unable to fulfill its osmo-protective function, the bacteria also suffer from osmotic stress. This study thus revealed that these three stresses are intimately linked in S. coelicolor. The aggravation of these stresses leading to an increase of antibiotic biosynthesis, the connection between these stresses, and antibiotic production are discussed.


Assuntos
Proteômica , Streptococcus , Streptomyces coelicolor , Antibacterianos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Nitrogênio/metabolismo , Fosfatos/metabolismo , Proteômica/métodos , Streptomyces coelicolor/genética , Streptomyces coelicolor/metabolismo , Fatores de Transcrição/metabolismo , Streptococcus/genética , Streptococcus/metabolismo
15.
Obstet Gynecol Surv ; 77(12): 753-762, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36477387

RESUMO

Importance: Group B Streptococcus (GBS) is a common pathogen with an effective treatment. However, it remains a significant cause of neonatal sepsis, morbidity, and mortality. The screening and management of this infection are some of the first concepts learned during medical training in obstetrics. However, effective screening and evidence-based management of GBS are nuanced with many critical caveats. Objective: The objectives of this review are to discuss the essential aspects of GBS screening and management and to highlight recent changes to recommendations and guidelines. Evidence Acquisition: Original research articles, review articles, and guidelines on GBS were reviewed. Results: The following recommendations are based on review of the evidence and professional society guidelines. Screening for GBS should occur between 36 weeks and the end of the 37th week. The culture swab should go 2 cm into the vagina and 1 cm into the anus. Patients can perform their own swabs as well. Penicillin allergy testing has been shown to be safe in pregnancy. Patients with GBS in the urine should be treated at term with antibiotic prophylaxis, independent of the colony count of the culture. Patients who are GBS-positive with preterm and prelabor rupture of membranes after 34 weeks are not candidates for expectant management, as this population has higher rates of neonatal infectious complications. Patients with a history of GBS colonization in prior pregnancy who are GBS-unknown in this current pregnancy and present with labor should receive intrapartum prophylaxis. Work on the GBS vaccine continues. Conclusions: Although all of the efforts and focus on neonatal early-onset GBS infection have led to lower rates of disease, GBS still remains a major cause of neonatal morbidity and mortality requiring continued vigilance from obstetric providers.


Assuntos
Streptococcus , Recém-Nascido , Humanos , Gravidez , Feminino
16.
Sci Rep ; 12(1): 21773, 2022 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-36526888

RESUMO

The number of patients on hemodialysis is increasing globally; diabetes mellitus (DM) complications is the major cause of hemodialysis in patients with chronic kidney disease (CKD). The D-amino acid (AA) profile is altered in patients with CKD; however, it has not been studied in patients with CKD and DM. Furthermore, bacteria responsible for altering the D-AA profile are not well understood. Therefore, we examined the D-AA profiles and associated bacteria in patients with CKD, with and without DM. We enrolled 12 healthy controls and 54 patients with CKD, with and without DM, and determined their salivary, stool, plasma, and urine chiral AA levels using two-dimensional high-performance liquid chromatography. We performed 16S rRNA gene sequencing analysis of the oral and gut microbiota to determine the association between the abundance of bacterial species and D-AA levels. Plasma D-alanine and D-serine levels were higher in patients with CKD than in healthy adults (p < 0.01), and plasma D-alanine levels were higher in patients with CKD and DM than in those without DM. The abundance of salivary Streptococcus, which produced D-alanine, increased in patients with CKD and DM and was positively correlated with plasma D-alanine levels. Patients with CKD and DM had unique oral microbiota and D-alanine profiles. Plasma D-alanine is a potential biomarker for patients with CKD and DM.


Assuntos
Diabetes Mellitus , Insuficiência Renal Crônica , Adulto , Humanos , RNA Ribossômico 16S/genética , Alanina , Insuficiência Renal Crônica/complicações , Bactérias/genética , Streptococcus/genética
17.
J Dairy Res ; 89(4): 449-452, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36484133

RESUMO

In the present research communication, we report on identification and quantification of four main lactic acid bacteria (LAB) genera (Lactococcus, Lactobacillus, Streptococcus and Leuconostoc), most common in Greek cheeses, by a novel culture-independent method. More specifically, new primers were designed to be used in both multiplex PCR for simultaneous identification and in real-time PCR for quantification of the LAB. The method was validated by applying it in parallel to culture-dependent method in a variety of cheeses from different Greek geographical locations, of different animal milk origins and of different production methods. While the standard plate culture method showed absence of Leuconostoc sp. in all cheeses, the culture-independent methods detected all four LAB genera studied. Furthermore, the relative presence of the four genera detected by the culture-independent method showed a pattern present in almost all cheese samples tested, indicating Lactococcus genus as the dominant one.


Assuntos
Queijo , Lactobacillales , Animais , Lactobacillales/genética , Queijo/análise , Grécia , Lactobacillus/genética , Streptococcus , Leite/microbiologia , Microbiologia de Alimentos
18.
Biocontrol Sci ; 27(4): 229-233, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36567120

RESUMO

The statistical correlation between the number of oral streptococci and the results of ATP bioluminescence assay was examined and compared with the results from Streptococcus plate counts and an oral bacteria quantification system. Because a significant correlation was found between ATP (RLU) and the number of bacteria in the oral bacteria quantification system for all seven types of oral streptococci examined, ATP would reflect a conditions of oral hygiene. However, using this assay, it was observed it may be difficult to correctly evaluate bacteria that form aggregates. Furthermore, even a small number of bacteria (below 105 CFU/mL) , which cannot be measured by the oral bacteria quantification system, could be estimated by using ATP bioluminescence assay. It was suggested that this assay could be used for quantitative evaluation of the effect of oral cleaning.


Assuntos
Trifosfato de Adenosina , Bactérias , Streptococcus , Medições Luminescentes/métodos , Contagem de Colônia Microbiana
19.
Commun Biol ; 5(1): 1190, 2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36336763

RESUMO

The mucosal adaptive immune response is dependent on the production of IgA antibodies and particularly IgA1, yet opportunistic bacteria have evolved mechanisms to specifically block this response by producing IgA1 proteases (IgA1Ps). Our lab was the first to describe the structures of a metal-dependent IgA1P (metallo-IgA1P) produced from Gram-positive Streptococcus pneumoniae both in the absence and presence of its IgA1 substrate through cryo-EM single particle reconstructions. This prior study revealed an active-site gating mechanism reliant on substrate-induced conformational changes to the enzyme that begged the question of whether such a mechanism is conserved among the wider Gram-positive metallo-IgA1P subfamily of virulence factors. Here, we used cryo-EM to characterize the metallo-IgA1P of a more distantly related family member from Gemella haemolysans, an emerging opportunistic pathogen implicated in meningitis, endocarditis, and more recently bacteremia in the elderly. While the substrate-free structures of these two metallo-IgA1Ps exhibit differences in the relative starting positions of the domain responsible for gating substrate, the enzymes have similar domain orientations when bound to IgA1. Together with biochemical studies that indicate these metallo-IgA1Ps have similar binding affinities and activities, these data indicate that metallo-IgA1P binding requires the specific IgA1 substrate to open the enzymes for access to their active site and thus, largely conform to an "induced fit" model.


Assuntos
Imunoglobulina A , Metaloproteases , Humanos , Idoso , Imunoglobulina A/metabolismo , Streptococcus/metabolismo , Bactérias/metabolismo , Fatores de Virulência
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