ABSTRACT
Objective To analyze the epidemiological characteristics of aggregative vomiting and diarrhea outbreak in Jing'an District of Shanghai in 2017 and 2018，and provide data support for further development of effective prevention and control measures. Methods A descriptive epidemiological method was used to analyze aggregative vomiting and diarrhea outbreak data in Jing'an District in 2017 and 2018. Results A total of 49 outbreaks were reported in Jing'an District in 2017 and 2018，involving 565 cases，with the overall attack rate of 1.89%. The median duration of the outbreak was 5 days and outbreaks mainly occurred in spring and autumn. The attack rate in kindergartens was higher than that in primary and secondary schools, while the total number of outbreak cases in kindergartens was less. The main clinical symptoms of the cases were vomiting, with a higher proportion than that of diarrhea and fever. The vomiting proportion was higher in kindergartens and elementary schools, while the diarrhea proportion was higher in middle schools. Conclusion There were some differences in the epidemic characteristics between kindergartens and primary and secondary schools, therefore different control measures should be adopted according to the characteristics of different institutions. The outbreaks were mainly spread through human-to-human transmission. Early detection and early reporting of epidemics in collective institutions had a positive impact on the control of the spread of the epidemic.
ABSTRACT
A ocorrência de fenótipos multirresistentes de Corynebacterium pseudodiphtheriticum e sua associação a infecções graves, com elevada mortalidade em pacientes imunocomprometidos, aliados ao escasso conhecimento da virulência e patogenia destas infecções, motivou esta pesquisa, que teve como objetivo investigar mecanismos de virulência e resistência microbiana deste agente entre pacientes de um hospital universitário brasileiro. Um total de 113 amostras de C. pseudodiphtheriticum identificadas por métodos bioquímicos convencionais e sistema API-Coryne isoladas de pacientes de diferentes grupos etários. Os micro-organismos eram, em sua maioria, relacionados a infecções no trato respiratório (27,45%), urinário (29,20%) e sitios intravenosos (18,60%) e cerca de 32,70% das amostras foram provenientes de pacientes com pelo menos uma das condições predisponentes: insuficiência renal; transplante renal, tuberculose em paciente HIV+, câncer, cirrose hepática, hemodiálise e uso de cateter. As amostras testadas revelaram-se multirresistentes sendo a maioria resistente à oxacilina, eritromicina e clindamicina. A adesão das cepas ao poliestireno e ao poliuretano indicou o envolvimento de hidrofobicidade da superfície celular na fase inicial da formação de biofilmes. O crescimento subsequente conduziu à formação de microcolônias, agregados bacterianos densos incorporados na matriz exopolimérica rodeada por espaços vazios, típica de biofilmes maduros...
The occurrence of multiresistant phenotypes and associated with severe infections, with high mortality in immunocompromised hosts due to Corynebacterium pseudodiphtheriticum, allied to little known about virulence and pathogenesis these infections, led to present investigation. The investigation aims to examine the virulence mechanisms and resistance to antimicrobial agents of C. pseudodiphtheriticum among patients with bacterial infections at a Brazilian teaching hospital. A total of 113 C. pseudodiphtheriticum strains identified by conventional biochemical methods and API-Coryne System were recovered from patients from different age groups. Micro-organisms were mostly related to infections in the respiratory tracts (27.45%), urinary (29.20%) and intravenous sites (18.60%) and approximately 32.70% samples were obtained of patients presenting at least one of the pre-disposing conditions: end-stage renal disease; renal transplant; AIDS and Mycobacterium tuberculosis infection; cancer, hepatic cirrhosis; haemodialysis and catheter use. Antimicrobial susceptibility tests identified multiresistant phenotypes. Most strains were resistant to oxacillin, erythromycin and clindamycin. Adherence to polystyrene and polyurethane indicated the involvement of cell surface hydrophobicity in the initial stage of biofilm formation. Further growth led to the formation of dense bacterial aggregates embedded in the exopolymeric matrix surrounded by voids, typical of mature biofilms...
Subject(s)
Humans , Male , Female , Child , Adult , Aged , Adhesins, Bacterial , Corynebacterium diphtheriae/pathogenicity , Drug Resistance, Bacterial , Immunocompromised Host , Cross Infection/microbiology , Drug Resistance, Microbial/immunology , Apoptosis , Apoptosis Inducing Factor , Bacterial Adhesion , Biofilms/growth & development , Corynebacterium diphtheriaeABSTRACT
Corynebacterium pseudodiphtheriticum is a well-known human pathogen that mainly causes respiratory disease and is associated with high mortality in compromised hosts. Little is known about the virulence factors and pathogenesis of C. pseudodiphtheriticum. In this study, cultured human epithelial (HEp-2) cells were used to analyse the adherence pattern, internalisation and intracellular survival of the ATCC 10700 type strain and two additional clinical isolates. These microorganisms exhibited an aggregative adherence-like pattern to HEp-2 cells characterised by clumps of bacteria with a "stacked-brick" appearance. The differences in the ability of these microorganisms to invade and survive within HEp-2 cells and replicate in the extracellular environment up to 24 h post infection were evaluated. The fluorescent actin staining test demonstrated that actin polymerisation is involved in the internalisation of the C. pseudodiphtheriticum strains. The depolymerisation of microfilaments by cytochalasin E significantly reduced the internalisation of C. pseudodiphtheriticum by HEp-2 cells. Bacterial internalisation and cytoskeletal rearrangement seemed to be partially triggered by the activation of tyrosine kinase activity. Although C. pseudodiphtheriticum strains did not demonstrate an ability to replicate intracellularly, HEp-2 cells were unable to fully clear the pathogen within 24 h. These characteristics may explain how some C. pseudodiphtheriticum strains cause severe infection in human patients.
Subject(s)
Humans , Bacterial Adhesion/physiology , Corynebacterium/pathogenicity , Epithelial Cells/microbiology , Corynebacterium/physiology , VirulenceABSTRACT
Objective To investigate the influence of Wnt-3a signaling on aggregative growth of dermal papilla cells.Methods Recombinant adenovirus pAdEasy-1/Wnt-3a was constructed at first,and used to transfect cultured dermal papilla cells(DPCs).Then,the growth pattem of DPCs was observed by inverse microscopy;laser confocal microscopy and Western blot were utilized to detect the expressions of Wnt-3a,β-catenin and versican in low-passage DPCs,high-passage DPCs and transfected high-passage DPCs.Results The over-expression of Wnt-3a protein could effectively induce the aggregative growth of DPCs.Laser confocal microscopy showed that the fluorescence intensity of β-catenin and versican increased from 34.16±9.62 and 18.81±9.59 in high-passage DPCs to 87.35±17.28 and 92.18±18.39 in transfected high-passage DPCs(t=11.98,17.88,both P＜0.0 1),respectively.Also,Western blot proved a significant increase of expression intensity of β-catenin(15.27±2.17 vs 60.09±7.24,t=10.10,P＜0.01)and versican(19.32±2.46 vs 58.46±2.78,t=20.63,P＜0.01)in transfected high-passage DPCs compared with untransfected high-passage DPCS.ConclusionsWnt-3a signaling plays an important role in modulating aggregative growth of DPCs,which is mainly through the classical pathway with β-catenin as the key protein.As an important downstream gene of Wnt signaling,vesican is an indispensable part for the modulation of aggregative growth of DPCs.
ABSTRACT
Invasive diseases caused by Corynebacterium diphtheriae have been described increasingly. Several reports indicate the destructive feature of endocarditis attributable to nontoxigenic strains. However, few reports have dealt with the pathogenicity of invasive strains. The present investigation demonstrates a phenotypic trait that may be used to identify potentially invasive strains. The study also draws attention to clinical and microbiological aspects observed in 5 cases of endocarditis due to C. diphtheriae that occurred outside Europe. Four cases occurred in female school-age children (7-14 years) treated at different hospitals in Rio de Janeiro, Brazil. All patients developed other complications including septicemia, renal failure and/or arthritis. Surgical treatment was performed on 2 patients for valve replacement. Lethality was observed in 40 percent of the cases. Microorganisms isolated from 5 blood samples and identified as C. diphtheriae subsp mitis (N = 4) and C. diphtheriae subsp gravis (N = 1) displayed an aggregative adherence pattern to HEp-2 cells and identical one-dimensional SDS-PAGE protein profiles. Aggregative-adhering invasive strains of C. diphtheriae showed 5 distinct RAPD profiles. Despite the clonal diversity, all 5 C. diphtheriae invasive isolates seemed to display special bacterial adhesive properties that may favor blood-barrier disruption and systemic dissemination of bacteria. In conclusion, blood isolates from patients with endocarditis exhibited a unique adhering pattern, suggesting a pathogenic role of aggregative-adhering C. diphtheriae of different clones in endocarditis. Accordingly, the aggregative-adherence pattern may be used as an indication of some invasive potential of C. diphtheriae strains.