Caries prevention mechanism of the Xinjiang Mori Cortex based on network pharmacology and its effect on the main cariogenic bacteria / 口腔疾病防治

Objective@#To investigate the potential caries prevention mechanism of the Xinjiang Mori cortex and to analyze its effect on the main cariogenic bacteria.@*Methods@#The active components of the Xinjiang Mori cortex and the main targets were predicted and screened using the TCMSP database. The GeneCards, DisGENET and TTD databases were used to obtain caries-related targets. The common targets were derived, and core genes were screened. The enrichment analysis was performed using the DAVID data platform. Molecular docking was performed using AutoDock software. In in vitro antibacterial experiments, first, the 50% minimum inhibitory concentration (MIC50) and the minimum bactericidal concentration (MBC) of the Xinjiang Mori Cortex extract against Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus were determined and the growth curves were measured. The effects of the Xinjiang Mori Cortex extract on acid production, polysaccharide production and adhesion ability of Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus in the planktonic state were determined. The 50% minimum biofilm inhibition concentration (MBIC50) and 50% minimum biofilm reduction concentration (MBRC50) were determined by crystal violet staining, and biofilm morphology was visualized using scanning electron microscopy (SEM).@*Results@#The main active components of the Xinjiang Mori cortex included quercetin, kaempferol, and β-sitosterol. Tumor necrosis factor (TNF), interleukin-6 (IL-6), and interleukin-1beta (IL-1β) could be the most important targets of the Xinjiang Mori cortex for the prevention of dental caries. The enrichment analysis results showed that Mori cortex extract may have effects on the AGE-RAGE signaling pathway, IL-17 signaling pathway, and TNF signaling pathway. The antibacterial experiment results showed that the MIC50 values of Xinjiang Mori Cortex extract against Streptococcus mutans, Streptococcus sanguis and Actinomyces viscosus were 0.5, 0.5 and 0.25 mg/mL, respectively, and the MBCs were 4.0, 2.0 and 1.0 mg/mL, respectively. The inhibitory effect of Xinjiang Mori Cortex extract on the acid production, polysaccharide production and adhesion ability of three major cariogenic bacteria in the planktonic state was stronger than that of the control group, and the differences were statistically significant (P<0.05). The MBIC50 was 1.0, 1.0, and 0.5 mg/mL, and the MBRC50 was 4.0, 4.0, and 2.0 mg/mL. SEM observation showed that the amount of biofilm formation decreased with the drug concentration compared with the control group.@*Conclusion@#Xinjiang Mori cortex extract can prevent caries through quercetin, kaempferol, and β-sitosterol active ingredients, TNF、IL-6、IL-1β key targets and multiple pathways and inhibit the growth, acid production, polysaccharide production, and adhesion ability of three major cariogenic bacteria in the planktonic state and has some inhibitory effect on corticogenic biofilm formation.

Bacteremia by non-O1/non-O139 Vibrio cholerae: Case description and literature review / Bacteriemia por Vibrio cholerae no-O1/no-O139: descripción de un caso y revisión de la literatura

Bacteremia by non-O1/non-O139 Vibrio cholerae is a rare entity associated with high mortality rates. We report a case of non-O1/non-O139 V. cholerae bacteremia confirmed by polymerase chain reaction and agglutination tests. The clinicoepidemiological characteristics and therapeutic options for this infection are also described.

La bacteriemia por Vibrio cholerae no-O1/no-O139 es una entidad poco frecuente que se asocia con altas tasas de mortalidad. Se reporta un caso de bacteriemia por V. cholerae no-O1/no-O139 confirmado por reacción en cadena de la polimerasa y test de aglutinación. Se describen las características clinicoepidemiológicas y las opciones terapéuticas para esta infección.

Regulation of Pyroptosis in Gastric Cancer by Traditional Chinese Medicine： A Review / 中国实验方剂学杂志

Pyroptosis， a new type of inflammatory programmed cell death， is different from apoptosis， necrosis， cytosis， ferroptosis， and autophagy. Pyroptosis is dependent on the activation of cysteine aspartate-specific protease （Caspase）， which cleaves key mediator proteins to form pores in the cell membrane and induces the maturation and release of the proinflammatory cytokines interleukin-1β and interleukin-18 into the extracellular environment， resulting in a cascade of inflammatory reactions. Gastric cancer as a malignant tumor of the digestive tract is refractory and has poor prognosis， and the chemoradiotherapy of this disease may lead to a variety of complications. At present， the pathogenesis of gastric cancer remains unclear. Studies have proved that pyroptosis is associated with the occurrence and development of gastric cancer， which has attracted wide attention. Pyroptosis is a double-edged sword for gastric cancer. On the one hand， it can release the contents of proinflammatory cells to amplify or maintain inflammation and induce the "inflammation-cancer" transformation of cells. On the other hand， pyroptosis can enhance the sensitivity of drugs for chemotherapy to improve the therapeutic effect and survival. In recent years， the anti-tumor mechanism of traditional Chinese medicine （TCM） has become a research hotspot as TCM has demonstrated significant effects in clinical application. Therefore， the regulation of pyroptosis by TCM may be a new direction for the treatment of gastric cancer in the future. Based on the available studies， this paper introduces the roles of pyroptosis-associated key proteins in the occurrence and development of gastric cancer. Furthermore， this paper summarizes the effects of TCM prescriptions and active ingredients on alleviating gastric mucosal damage， reducing the incidence of gastric cancer， and preventing tumor metastasis and recurrence by mediating pyroptosis pathways， aiming to provide new ideas for deciphering the mechanism of pyroptosis and exploring the TCM treatment of gastric cancer in the future.

Clinico-microbiological Profile of Urinary Tract Infection with Special Reference to Uropathogenic E coli : Antibiotic susceptibility Pattern, Phylogenetic Background and Virulent Factor Distribution from West Bengal, India

Background and Objectives : Routine surveillance and monitoring studies pose a constant need to update clinicians on prevalent pathogens and rational and empirical treatment in Urinary Tract Infection (UTI). Escherichia coli (E coli) is the most commonly isolated uropathogen globally. Extended-Spectrum ?-Lactamase (ESBL) production and ?-Lactamase Inhibitor Resistance (BLIR) among these pathogens together with their uro-virulence determinants further complicate treatment approaches. This study investigated the clinico-microbiological pattern of UTI and determined the antibiotic sensitivity pattern, the phylogenetic background, and virulence determinants of E coli, the most commonly isolated uropathogen. Methods : Uropathogens isolated by urine culture from community and hospitalized patients were biochemically speciated. Antibiotic susceptibility was tested by Kirby-bauer disk diffusion method. Phylogenetic background and virulence determinants of E coli isolates were identified by PCR. SPSS 16.0 was used for statistical interpretation. Results : 45% of the urine samples showed growth positivity. 44% amongst them were E coli. All isolates were multidrug-resistant. 50% and 40% were ESBL producers and BLIR respectively. Former showed highest resistance to quinolone, fluoroquinolones, cotrimoxazole, and latter were resistant against all drugs tested except nitrofurantoin. Significant correlation existed between the ?-lactams, quinolone, fluoroquinolones, cotrimoxazole (p<0.05) resistance pattern. BLIR and ESBL E coli recorded highest prevalence of pathogenic phylogroup B2 and D respectively. Varied prevalence of fimbrial (fimH, papC, papEF, papG, GII) and toxin genes (iroN, hlyA, cnfI, i ucD, cdtBU) in ESBL, BLIR and non-ESBL isolates were observed. Their distribution was statistically significant (p=0.05). Interpretation and Conclusions : Nitrofurantoin is the drug of choice in empirical treatment of uncomplicated UTI. Aggressive and consistent investigation and health education are highly recommended for effective clinical management in UTI.

Research progress on prime virulence factors and pathogenesis of brucellosis / 中华地方病学杂志

Brucellosis is an infectious zoonosis caused by Brucella infection. It is widely prevalent all over the world and brings great losses to the development of public health, animal husbandry and social economy in China. However, the understanding of the specific clinical indications of brucellosis, the virulence factors of Brucella and its pathogenesis is very limited, which leads some limitations in the clinical diagnosis and treatment of brucellosis. Starting from the current epidemic situation of brucellosis, this article focuses on the virulence factors of Brucella and pathogenesis of brucellosis, and comprehensively summarizes the activity track and state of Brucella in the infected organism during the pathogenesis of brucellosis, so as to provide new ideas for the in-depth study of the pathogenesis of brucellosis, and a comprehensive reference for vaccine development and clinical diagnosis and treatment.

Effect of Fufang Huangbai Fluid Paint on Virulence and Biofilm of Methicillin-resistant Staphylococcus aureus / 中国实验方剂学杂志

ObjectiveTo study the virulence and biofilm inhibition effect of Fufang Huangbai Fluid Paint （FFHBFP） on methicillin-resistant Staphylococcus aureus （MRSA）， and to explore the antibacterial effect of FFHBFP on MRSA， which provides a theoretical basis and reference for clinical medication. MethodFirstly， the microdilution method and time–growth curve were used to determine the minimum inhibitory concentration （MIC） of FFHBFP and vancomycin （VAN） against MRSA and the effect on bacterial growth. The effects of FFHBFP and VAN on the inhibition of MRSA virulence factor lipase and restoration of hydrogen peroxide （H2O2） sensitivity were detected under sub-minimum inhibitory concentration （sub-MIC）. The inhibitory effect of FFHBFP and VAN on MRSA biofilm formation and maturation was detected by the microplate method. The morphological changes of mature biofilms before and after administration were observed under a scanning electron microscope （SEM）. Real-time polymerase chain reaction （Real-time PCR） was utilized to detect the effect of 50.600 g·L-1 concentration of FFHBFP on the expression of MRSA virulence gene crtM and biofilm-forming genes fnbA and icaA. Finally， molecular docking technology was used to predict the mechanism of potential antibacterial active ingredients of FFHBFP in inhibiting the virulence and biofilm of MRSA. ResultThe MIC of VAN was 2 mg·L-1， and VAN below 1 mg·L-1 exerted no effect on MRSA growth. The MIC of FFHBFP was not determined， while the 101.200-202.400 g·L-1 original solution inhibited MRSA growth. Compared with the blank group and the VAN group， sub-MIC （25.300-50.600 g·L-1 original solution） inhibited lipase and recovered MRSA sensitivity to H2O2 （P<0.01）. The results of the microplate method showed that FFHBFP （25.300-202.400 g·L-1 original solution） inhibited biofilm formation and maturation （P<0.05， P<0.01）. The SEM exhibited that FFHBFP made the structure of biofilm loose and the size of the bacteria varied. FFHBFP at 50.600 g·L-1 concentration can inhibit the expression of related virulence genes and biofilm-forming genes （P<0.05， P<0.01）， and molecular docking results also showed that the main antibacterial active ingredients in FFHBFP have good binding ability to the target. ConclusionFFHBFP that cannot directly kill MRSA exerts clinical efficacy by impairing virulence expression， biofilm formation， and other pathogenic properties.

A preliminary study on the nature of plague epidemic in Jianchuan County, Yunnan Province / 中华地方病学杂志

Objective:To explore the biochemical characteristics, virulence factors and other phenotypes of the strains of Yersinia pestis isolated in Jianchuan County Yunnan Province in 2017, and to analyze the nature and source of the new plague epidemic. Methods:Three strains of Yersinia pestis (JC109 rat, JC109 fleas and JC113) isolated from Daqing Village, Jinhua Town, Jianchuan County, Dali Prefecture, Yunnan Province in 2017, and 2 associated strains of Yersinia pestis (LJ01 in Yulong County, Lijiang City and LJ04 in Gucheng District of Lijiang City), 5 control strains ( Yersinia pestis JC1332, LJ485, BN2636, EV-76 and Yersinia pseudotuberculosis PST-1), preserved by the Central Laboratory of Yunnan Institute for Endemic Disease Control and Prevention were collected. The biochemical characteristics and ecotypes of Yersinia pestis were analyzed by using arabinose, rhamnose, denbiose, maltose and glycerol fermentation experiments and nitrate reduction experiments. Combining pigmentation factor (pgm), virulence antigen (VW) detection and nutritional requirements test results to determine the virulence of Yersinia pestis. Results:The Yersinia pestis JC109 rat, JC109 fleas and JC113 all fermented arabinose, maltose and glycerol, but didn't ferment rhamnose and denbiose; and the nitrate reduction test was positive. The ecological type belonged to the Himalayan Marmot plague strain of Qinghai-Tibet plateau. The virulence factors pgm and VW tests were positive, the nutritional requirement type was phenylalanine dependent and glutamate independent. It had the same phenotype as the LJ01 strain, but different from the JC1332 strain. Conclusions:The newly isolated strains in Jianchuan County are the same as those in the Lijiang Yulong wild rodent plague foci. This outbreak may have been imported from the Lijiang Yulong wild rodent plague foci to the south.

Design, synthesis and biological activity of novel triazine inhibitors of Candida albicans secreted aspartic protease 2 / 药学学报

In recent years, the incidence and mortality of invasive fungal infections has increased. It is highly desirable to develop novel antifungal agents with new modes of action. Targeting virulence factors represents a new strategy for antifungal drug discovery. Secreted aspartic protease 2 (SAP2), a kind of virulence factor, is an emerging antifungal target. However, discovery of small-molecule SAP2 inhibitors remains a significant challenge. Based on the structure-activity relationship of our previously identified triazine small-molecule SAP2 inhibitor, we were able to identify two potent inhibitors, 8a and 8c, which showed excellent in vivo antifungal activity for the treatment of C. albicans infection. Moreover, compounds 8a and 8b effectively inhibited fungal biofilm. Taken together, triazine SAP2 inhibitors represent promising lead compounds for the discovery of novel antifungal agents.

Prevalencia de cepas del grupo de Bacillus cereus productoras de biopelicula en helados comercializados en México / Prevalence of strains of the Bacillus cereus group biofilm producers in ice cream in Mexico

El helado es un vehículo para la transmisión de patógenos como Bacillus cereus. Por lo cual, se determinó la frecuencia de cepas del grupo Bacillus cereus en helados, perfil enterotoxigénico, psicrofilia y producción de biopelícula. Un total de 230 muestras de seis marcas de helado de producción y distribución nacional fueron colectadas en México. El análisis microbiológico incluyó aislamiento en agar manitol yema de huevo. Las cepas se identificaron molecularmente a partir de la amplificación del gen de la topoisomerasa (gyrB) y el perfil enterotoxigénico por la amplificación de regiones conservadas de los operones nheABC y hblABD y del gen cytK. Además, se determinó la producción de biopelícula en vidrio y policloruro de vinilo. La frecuencia de contaminación por cepas del grupo B. cereus fue de 3,6%, se encontró una cepa positiva para nheABC y cinco para cytK, el 87,5% de las cepas generó biopelícula en vidrio y todas en policloruro de vinilo, dos cepas fueron psicrofilicas. En conclusión, en el helado distribuido en México, se encontró una baja contaminación por cepas del grupo B. cereus con alta producción de biopelícula; sin embargo, no se debe subestimar el potencial enterotoxigénico de estas cepas

Ice cream is a medium for microbial growth due to its nutritional value and neutral pH. Therefore, the frequency of strains of the Bacillus cereus group in ice cream was determined, the enterotoxigenic profile, psychrophilic strains and biofilm production. A total of 230 samples of six brands of ice cream produced and distributed nationwide were collected in Mexico. The microbiological analysis was a cold pre-enrichment and isolation of the microorganism in egg yolk agar. The strains were identified molecularly from the amplification of the topoisomerase gene (gyrB) and the enterotoxigenic profile by the amplification of conserved regions of the nheABC and hblABD operons and of the cytK gene. In addition, the production of biofilm in glass and polyvinyl chloride and psychophilia was determined. The frequency of contamination by strains of the B. cereus group was 3.6%, a positive strain was found for nheABC and five for cytK, 87.5% of the strains generated biofilm in glass and all in polyvinyl chloride, two strains were psychrophilic. In the ice cream distributed in Mexico, a low contamination by strain of the B. cereus group was found, however, the enterotoxigenic potential of the strains should not be underestimated

Methionine Sulfoxide Reductase Enzymes: A Possible Virulence Factor for the Management of Antibiotic Resistance Crisis in the Climate Change Era

The problem of antibiotic resistance develops when bacteria are able to grow in the presence of conventional antimicrobial drugs and today represents a serious public health issue. The environmental effects of global warming, by unknown genomic mechanisms of adaption, could dramatically increase this phenomenon and support a more rapid progression to “post-antibiotic era”, in which common infections will be untreatable. Alternative approaches toward drug-resistant bacterial infections need to be explored to ensure effective therapies. Bacterial pathogens produce virulence factors that allow them to invade and to damage host cells. Methionine sulfoxide reductase (Msr) enzymes (MsrAs and MsrBs) are important, but poor studied, virulence factors for many bacterial strains. A deeper insight into their mechanism of action and regulation could help in developing novel therapeutic strategies toward drug-resistant bacteria, in order to overcome the antibiotic resistance crisis.

Isolation of a putative virulence agent, cytotoxic serine-elastase,from a newly isolated Pseudomonas aeruginosa ZuhP13

A 48 kDa ZuhP13 elastase from P. aeruginosa isolated from a urine sample was successfully purified to 8.8-fold and 39%recovery by DEAE-Sepharose CL-6B and Sephadex G-100 chromatography. Its ideal reaction values were pH 7.5 and40C. It showed stability at pH 6–9 for 1 h and up to 60C for 30 min with midpoint temperature (Tm) at 61.3Cand isoelectric value (pI) at 5.6±0.2. Its Km and catalytic efficiency (Kcat/Km) for the substrate azocasein were 1.3 mg/mLand 4.629107 M-1s-1, respectively. On contrary to most P. aeruginosa proteases, Zn2?, EDTA, 2,20-bipyridine ando-phenanthroline showed slight inhibition upon its activity, while, the elastase inhibitors (elastatinal and elastase inhibitorII) and the serine protease inhibitors (TLCK, PMSF, SBTI, and aprotinin) markedly decreased the enzymatic activity. Takentogether, we suggest that ZuhP13 is a serine elastase-type. Interestingly, the tested enzyme showed both hemolytic andhemorrhagic activities in vivo. Furthermore, it induced nuclear lysis yielding hyperchromatism within leaky and malformedhepatocytes, suggesting ZuhP13 elastase as a high molecular weight potential pathological agent.

Antifungal activity of some Sternbergia taxa: effects on germ tube and biofilm formation

Natural products are rapidly becoming the primary sources of novel antimicrobial agents, as resistance to existing antimicrobial agents is increasing. Apart from determining the antimicrobial activity of natural products, it is also important to understand their effects on the virulence factors of microorganisms. This study aimed to determine the antimicrobial activity of Sternbergia species prevalent in Turkey and investigate their role in the inhibition of germination tube and biofilm formation, both of which are known to be important virulence factors of Candida albicans. The antimicrobial activities of the plant extracts were evaluated using bore-plate and broth microdilution method. The extracts' capacity to inhibit the formation of the germ-tube was also evaluated. The findings of our study revealed that Sternbergia lutea, Sternbergia vernalis possessed antimicrobial activities, with MIC values ranging between 0.048 mg/mL and 0.39 mg/mL. The highest antimicrobial activity was observed against Candida dubliniensis (0.048 mg/mL). While evaluating the inhibition of fungal germination activities, S. vernalis extract (at a concentration of 0.09 mg/mL) was found to be the most effective against C. albicans ATCC 90028 strain. The results also indicated that S. vernalis extracts at sub-MIC levels inhibited germ tube formation and modulated the tail-length of germinated cells, both of which are important virulence factors of C. albicans. Furthermore, the inhibition of biofilm-formation was also investigated, and it was found that two Sternbergia spp. extracts at or below MIC levels inhibited biofilm formation.

Biofilm formation by Prototheca zopfii isolated from clinical and subclinical bovine mastitis in distinct growth conditions under different dyes / Formação de biofilme por Prototheca zopfii isolados de mastite bovina clínica e subclínica em distintas condições de crescimento sob diferentes corantes

ABSTRACT: Prototheca spp. have been reported as an emergent environmental mastitis pathogen in several countries. Biofilm formation is a significant factor associated with different degrees of virulence developed by many microorganisms, including Prototheca spp. The present study aimed to compare two growth conditions and two staining dyes to determine which combination was more appropriate to evaluate qualitatively and quantitatively the production of biofilm by P. zopfii. Biofilm formation was evaluated in polystyrene microplates under static and dynamic growth conditions and staining with crystal violet or cotton blue dye. All P. zopfii isolates from cows with mastitis were classified as biofilm-producers in all growth conditions and staining. The cotton blue dye proved to be more appropriate method to classify the intensity of P. zopfii biofilm production.

RESUMO: Prototheca spp. tem sido relatado como um patógeno ambiental causador de mastite bovina em vários países. A formação de biofilme é um fator associado a diferentes graus de virulência desenvolvidos por muitos microrganismos, incluindo Prototheca zopfii. O presente estudo teve como objetivo comparar duas condições de crescimento e dois corantes para determinar a combinação mais adequada para avaliar qualitativa e quantitativamente a produção de biofilme por P. zopfii. A formação de biofilme foi avaliada em microplacas de poliestireno sob condições estáticas e dinâmicas de crescimento e coloração com cristal violeta ou azul de algodão. Todos os isolados de P. zopfii de vacas com mastite foram caracterizados como produtores de biofilme, independentemente das condições de crescimento e coloração. O corante azul de algodão demonstrou ser o método mais adequado para classificar a intensidade de produção de biofilme de P. zopfii.

Advances in the research of factors impacting on helicobacter pylori eradication / 医学研究生学报

In the eradication of Helicobacter pylori, China has carried out more than 30 years of efforts. The treatment plan has evolved, but the eradication rate has not increased significantly, and even has a downward trend. How to improve the eradication rate of Helicobacter pylori is an urgent problem for our clinicians. Combined domestic and foreign literature with new clinical progress, this paper reviews from many aspects, such as Hp related factors, drug factors, patient factors, other factors, and many other aspects, in order to provide some help for clinical treatment.

Virulence genes of Streptococcus mutans and dental caries

Streptococcus mutans is one of the important bacteria that forms dental biofilm and cause dental caries. Virulence genes in S. mutans can be classified into the genes involved in bacterial adhesion, extracellular polysaccharide formation, biofilm formation, sugar uptake and metabolism, acid tolerance, and regulation. The genes involved in bacterial adhesion are gbps (gbpA, gbpB, and gbpC) and spaP. The gbp genes encode glucan-binding protein (GBP) A, GBP B, and GBP C. The spaP gene encodes cell surface antigen, SpaP. The genes involved in extracellular polysaccharide formation are gtfs (gtfB, gtfC, and gtfD) and ftf, which encode glycosyltransferase (GTF) B, GTF C, and GTF D and fructosyltransferase, respectively. The genes involved in biofilm formation are smu630, relA, and comDE. The smu630 gene is important for biofilm formation. The relA and comDE genes contribute to quorum-sensing and biofilm formation. The genes involved in sugar uptake and metabolism are eno, ldh, and relA. The eno gene encodes bacterial enolase, which catalyzes the formation of phosphoenolpyruvate. The ldh gene encodes lactic acid dehydrogenase. The relA gene contributes to the regulation of the glucose phosphotransferase system. The genes related to acid tolerance are atpD, aguD, brpA, and relA. The atpD gene encodes F1F0-ATPase, a proton pump that discharges H⁺ from within the bacterium to the outside. The aguD gene encodes agmatine deiminase system and produces alkali to overcome acid stress. The genes involved in regulation are vicR, brpA, and relA.

Analysis of genomic characteristics and virulence factors of emetic-type Bacillus cereus strains isola-ted in Hangzhou / 中华微生物学和免疫学杂志

Objective To investigate the genomic characteristics and virulence factors of emetic-type Bacillus cereus strains isolated from food in Hangzhou for better understanding their pathogenic potential. Methods Real-time PCR was performed to detect the ces gene cluster ( cereulide) in 132 Bacillus cereus strains isolated from food from 2015 to 2017. Genomes of cereulide-positive strains were sequenced using Illumina MiSeq sequencing platform. Genome annotation, virulence factor detection, comparative and evolu-tionary analysis were performed after the sequences of genomes were assembled. Results Twelve strains (9. 09％) carried the ces gene. Their genome sizes ranged from 5. 35 to 5. 75 Mb and GC contents from 35. 25 to 35. 43 mol％. All of them harbored the full cereulide biosynthesis gene cluster, nonhemolytic ente-rotoxin ( NHE)-encoding gene cluster ( nheA, nheB and nheC) and hemolysinⅢ( hlyⅢ) . The average nu-cleotide identity ( ANI ) between the 12 isolates and the reference strain NC7401 ( Accession number:AP007209) was over 99. 35％. Phylogenetic analysis demonstrated these strains were clustered into the same branch with local clinical isolates and the emetic-type Bacillus cereus strains of NC7401 and AH187. Con-clusions The genomic sequences of the emetic-type Bacillus cereus strains isolated from food in Hangzhou area were highly similar to that of the reference strain NC7401. Results of the genomic analysis suggested that these isolates carried many virulence factors that were related to pathogenicity.

Detecção de Aeromonas spp. e do gene de virulência aerolisina em tilápias do Nilo (Oreochromis niloticus) com a técnica de mPCR / Detection of Aeromonas spp. and virulence gene aerolysin in Nile tilapia (Oreochromis niloticus) using PCR technique

As infecções causadas por bactérias do gênero Aeromonas estão entre as doenças mais comuns em peixes cultivados em todo o mundo, com ocorrência de aeromoniose em todos os países que possuem cultivo de tilápia do Nilo (Oreochromis niloticus). O presente trabalho descreve o desenvolvimento de uma nova multiplex PCR (mPCR) para diagnóstico de Aeromonas spp. e identificação do gene aerolisina (aerA). Para padronização da mPCR foram utilizadas cepas de referência de várias espécies do gênero Aeromonas e de outros gêneros. Também foram usadas cepas de campo de A. hydrophila oriundas de cultivos de peixes pacamãs (Lophiosilurus alexandri) e Aeromonas spp. de tilápias do Nilo. Os primers foram desenhados com base na região 16S rRNA e aerA. Para verificar a melhor temperatura de anelamento foram utilizados gradientes entre 59°C a 61°C com 40ng de DNA molde. Os produtos da amplificação da região 16S rRNA e do gene aerA apresentaram 786 e 550pb, respectivamente. A mPCR apresentou melhor temperatura de anelamento a 57,6°C com limite de detecção das concentrações de DNA em ambos genes (16S rRNA and aerA) de 10-10g/μL. A mPCR padronizada é rápida, sensível e específica no diagnóstico de Aeromonas spp. e identificação do gene aerolisina. Esta metodologia apresenta vantagens quando comparada aos métodos de diagnóstico convencionais, podendo ser utilizada em cultivos comerciais de tilápias do Nilo ou outros peixes. A identificação do gene aerolisina é uma importante ferramenta na determinação do potencial patogênico dos isolados de Aeromonas spp. estudados.(AU)

Infections caused by bacteria of the genus Aeromonas are among the most common diseases in fish farming systems worldwide, and this disease occurs in all countries which have Nile tilapia (Oreochromis niloticus) farmed. The present work describes the development of a new multiplex PCR (mPCR) technique that diagnosis the genus Aeromonas and detects aerolysin gene (aerA). Reference strains of several Aeromonas species and other genera were used for standardization of mPCR. Strains of A. hydrophila from "pacaman" fish (Lophiosilurus alexandri) and Aeromonas spp. from Nile tilapia from farming systems were used too. Primers were designed based on the 16S rRNA region and aerA (aerolysin toxin). To verify a better annealing temperature were used gradients between 59°C and 61°C with 40ng of the DNA template. The 16S rRNA gene and the aerA gene amplification products showed 786 and 550 bp, respectively. The mPCR showed better annealing temperature at 57.6°C, and the detection limit for both genes (16S rRNA and aerA) was 10-10g/μL of the DNA. The standardized mPCR is quick, sensitive, and specific for Aeromonas spp. diagnosis and to detect aerolysin gene. This method showed advantages when compared to the conventional diagnostic methods and can be used in Nile tilapia or other fish farming systems. The detection of aerolysin gene is an important tool to determine the potential pathogenicity of Aeromonas spp. isolates.(AU)

Relationship between virulence factor genes in coagulase-negative Staphylococcus spp. and failure of antimicrobial treatment of subclinical mastitis in sheep / Relação entre genes de fatores de virulência em Staphylococcus spp. coagulase-negativos e a falha do tratamento antimicrobiano da mastite subclínica ovina

Coagulase-negative Staphylococcus spp. (CNS) are the main microorganisms involved in ovine mastitis. Treatment at the end of lactation can contribute towards cure and prevention of subclinical cases during the subsequent lactation. However, virulence factors and resistance mechanisms presented by CNS can decrease cure rates. The aims of the study were to identify the species of CNS in milk of mastitic ewes with and without antimicrobial treatment, and to investigate the presence of genes relating to resistance of β-lactam antimicrobials, formation of biofilms, production of enterotoxins and production of the toxic shock syndrome toxin. Cases of failure in the treatment were related with the presence/absence of the respective genes. Sixty sheep were divided into three groups: G1, without treatment; G2, animals treated via the intramammary route with 100mg of cloxacillin during drying off; and G3, sheep treated via the intramammary route with 50 mg of nanoparticulate cloxacillin. Milk samples were gathered during drying off and 15 and 30 days after the parturition of the subsequent lactation. The analyses to identify the species of CNS were carried out by means of the internal transcribe spacer technique and the investigation of the genes responsible for the virulence factors and resistance to oxacillin was performed using the polymerase chain reaction (PCR) technique. No sample was positive for the mecA gene. The only gene relating to production of enterotoxins was sec. Among the genes relating to production of biofilm, icaD was the only one identified in the three experimental groups. Staphylococcus warneri was the main species of CNS isolated during the pre and post-partum periods of the sheep. The species carrying genes relating to production of enterotoxins and biofilms were present in uncured sheep.(AU)

Staphylococus spp. coagulase-negativos (SCN) estão entre os principais micro-organismos envolvidos na mastite ovina. O tratamento ao final da lactação pode contribuir com a cura e a prevenção de casos subclínicos durante a lactação seguinte. Todavia, fatores de virulência e mecanismos de resistência apresentados por SCN podem reduzir as taxas de cura. Os objetivos desse estudo foram identificar as espécies de SCN no leite de ovelhas com mastite com e sem tratamento antimicrobiano e investigar a presença de genes relacionados com resistência a antibióticos beta lactâmicos, formação de biofilmes, produção de enterotoxinas e produção da toxina da síndrome do choque tóxico. Casos de falhas no tratamento foram relacionados com a presença/ausência dos respectivos genes. Sessenta ovelhas foram divididas em três grupos: G1, sem tratamento; G2, animais tratados via intramamária com 100mg de cloxacilina antes da secagem; e G3, ovelhas tratadas via intramamária com 50 mg de cloxacilina nanoparticulada. Amostras de leite foram obtidas durante a secagem e 15 e 30 dias depois do parto na lactação seguinte. As análises para identificar as espécies de SCN foram conduzidas por meio da técnica de Internal transcribe spacer e a investigação dos genes responsáveis pelos fatores de virulência e resistência à oxacilina foi realizada usando a técnica reação em cadeia da polimerase. Nenhuma amostra foi positiva para o gene mecA. O único gene relacionado com a produção de enterotoxinas foi o sec. Dentre os genes relacionados com a produção de biofilme, icaD foi o único identificado nos três grupos experimentais. Staphylococcus warneri foi a principal espécie de SCN isolada durante o pré e pós-parto. As espécies que apresentaram genes relacionados com a produção de enterotoxinas e biofilmes estavam presentes nas ovelhas não curadas.(AU)

CagA and VacA genes of Helicobacter pylori and their clinical relevance

Context: Helicobacter pylori is associated with the development of a variety of gastroduodenal diseases which varies with ethnicity and the type of strains that infect the population. Aims: This study aims to evaluate the prevalence of H. pylori cagA and vacA genotypes in our region and to determine their relationship to the severity of the lesions that they cause. Settings and Design: This study was an observational cross-sectional study. Subjects and Methods: DNA was extracted from 165 gastric biopsies from patients evaluated for dyspepsia. PCR was used to detect cagA and vacA (s1, s2, m1, m2) genes of H. pylori. Statistical analysis of associations was performed between endoscopy findings and virulence genes. Statistical Analysis Used: Pearson Chi-square test and Fischer's exact test. Results: The prevalence of H. pylori infection was 37% and the dominant genotypes was vacA s1 cagA-positive strain (54.1%) in this study. The vacAs1 subtype was found in all patients with peptic ulcer disease (PUD). The entire normal study group had VacA s2 variant only. This clearly shows that vacA s1 is a significant virulence marker and patients harboring s1 strains are more prone to develop ulcers (P = 0.007). There was a significant association of cagA with s1 strain rather than s2. Variation in VacA m genotype did not seem to have any association with disease status. There was a statistically significant association between the presence of cagA gene and PUD rather than the nonulcer dyspepsia (P = 0.027). Conclusion: The predominant genotype in our population was cagA positive vacA s1, which was found to be significantly associated with patients with gastric diseases, especially PUD. VacA s1 can serve as a single best virulence marker of the disease manifestation.

A review of research on staphylococcal phenol-soluble modulins / 中华微生物学和免疫学杂志

Phenol-soluble modulins (PSMs) are a novel family of small amphipathic, alpha-heli-cal peptides with strong surfactant-like properties. PSMs have multiple roles in staphylococcal pathogenesis and are considered as important virulence-associated factors. They may cause lysis of many eukaryotic cells, such as human neutrophils,erythrocytes and dendritic cells;induce the expression of pro-inflammatory cyto-kines;facilitate the structuring and detachment of biofilms;influence the expression of other genes. This re-view summarizes the classification,structure,regulatory effect on gene expression and biological function of PSMs. The potential avenues to target PSMs for drug development against staphylococcal infections are also evaluated in this paper.