RESUMO
Abdominal aortic aneurysm remains mostly asymptomatic. It is usually detected incidentally with imaging studies. Here we present a 55 years old hypertensive, non smoker, non diabetic, male patient who was diagnosed as a case of infrarenal abdominal aortic aneurysm. He was treated by endovascular means using endograft without laparatomy. Endografts were deployed through bilateral femoral artery cut down technique under general anesthesia. Completion angiogram following this endovascular aneurysm repair (EVAR) technique revealed good technical success with no endoleak. This hybrid procedure was performed in a cathlab having surgical instruments in hand. Three years after the procedure, patient is doing well.
Assuntos
Aneurisma da Aorta Abdominal , Correção Endovascular de Aneurisma , Humanos , Masculino , Pessoa de Meia-Idade , Aneurisma da Aorta Abdominal/cirurgia , Bangladesh , Correção Endovascular de Aneurisma/métodosRESUMO
Nephrotic syndrome (NS) represents a heterogenous group of glomerular disorders occurring mainly in children. Accumulated data suggest that patient with NS have an immunological basis. This cross-sectional comparative study was conducted in the Department of Paediatrics, Mymensingh Medical College Hospital (MMCH), Mymensingh during the period of March 2018 to October 2019 to determine the relationship of serum IgE level in frequent relapse and infrequent relapse nephrotic syndrome in children. Thirty cases of frequent relapse and 30 cases of infrequent relapse idiopathic nephrotic syndrome who were admitted in Department of Paediatrics, MMCH were included in this study by purposive sampling technique. After admission written informed consent from parents or guardians obtained. Serum IgE level was measured in all patients of idiopathic nephrotic syndrome during relapse and again four weeks after steroid therapy when patient was in remission. Serum total IgE levels were measured by ADVIA centaur CP immunoassay system. Most of the patient's age was within 2-6 years in both groups. Male children were predominant in both groups. Most of the patients came from rural area. Frequency of relapse per year was significantly higher and 24 hours urine output was significantly lower in frequent relapse nephrotic syndrome than that of infrequent relapse nephrotic syndrome. Significantly higher mean IgE was found in children with frequent relapse nephrotic syndrome (1439.8±388.5 IU/ml during relapse and 852.3±103.7 IU/ml at remission) than infrequent relapse nephrotic syndrome (1109.5±248.3 IU/ml during relapse and 776.6±108.5 IU/ml at remission) at both relapse and remission state. A linear, positive, significant correlation was found between rate of relapse and serum IgE level (Pearson correlation coefficient, r=0.674). Based on results it is concluded that serum IgE is high in relapsing nephrotic syndrome and it is persistently and significantly higher in frequent relapse nephrotic syndrome than infrequent relapse nephrotic syndrome.
Assuntos
Síndrome Nefrótica , Criança , Humanos , Masculino , Pré-Escolar , Síndrome Nefrótica/tratamento farmacológico , Estudos Transversais , Recidiva , Doença Crônica , Imunoglobulina ERESUMO
Hyponatremia is the most common electrolyte imbalance seen in clinical practice and a common laboratory findings in children with community acquired pneumonia. This study aimed to find out relationship between clinical profile, severity and outcome of community acquired pneumonia with hyponatremia in children aged 2-60 months. This descriptive cross-sectional study was done in pediatrics department of Mymensingh Medical College Hospital, Bangladesh. Study period was 6 month from November 2016 to April 2017. Data were collected from 2 months to 60 months old children who fulfill the selection criteria. In this study sampling technique was purposive. Detailed history was taken, and meticulous examinations and relevant investigations were performed. 100 patients with community acquired pneumonia were enrolled, 34.0% patient had hyponatremia and 66.0% patients had no hyponatremia. Hyponatremia is more marked (45.5%) in severe pneumonia followed by moderate pneumonia (33.3%) and no hyponatremia found in mild pneumonia. Mean temperature, respiratory rate, heart rate, head nodding, nasal flaring, grunting, stridor, cyanosis, convulsion, feeding problem, Poor air entry were significantly higher in patient of pneumonia with hyponatremia when compared to patient of pneumonia without hyponatremia. Mean duration of symptoms and mean duration of hospital stay were also significantly higher in patient of pneumonia with hyponatremia. The mean serum sodium concentration was 132.18±1.51mmol/L in hyponatremic patients and 137.91±1.94mmol/L in normonatremic patients. Mean values of total leucocyte count, ESR, and C-reactive protein were significantly higher in patient of pneumonia with hyponatremia. Serum hemoglobin was significantly lower in hyponatremic patients than normonatremic patients. Maximum (55.9%) patients of community acquired pneumonia (CAP) with hyponatremia had patchy opacity, 26.5% had consolidation, 11.8% had interstitial opacity and 5.9% had pneumatocele. All the patients were treated with appropriate antibiotics and fluid and discharged after complete recovery without any complication. There was no death in the study population. From this study we can conclude that, hyponatremia is directly related with the severity of community acquired pneumonia (CAP). The intensity of clinical profile and investigation findings are also directly related with the severity of pneumonia.
Assuntos
Hiponatremia , Pneumonia , Humanos , Criança , Lactente , Estudos Transversais , Pneumonia/complicações , Hiponatremia/etiologia , Hiponatremia/terapia , AntibacterianosRESUMO
High blood pressure and its related problems are progressively assuming public health dimensions in developing countries like Bangladesh. There was a suggestion that hypertensive process can be aborted in its early stages. But it is poorly understood in its early stages. So, early natural history of hypertension and its evolution from the youth needs to be investigated. Objective of this study was to determine blood pressure distribution in school children aged 6-15 years. This descriptive cross-sectional study was conducted in the Department of Paediatrics, Mymensingh Medical College, Mymensingh, Bangladesh from November 2014 to October 2015. The sample was collected by simple random sampling from five different schools of Mymensingh after applying inclusion and exclusion criteria. After taking proper history and doing relevant examination, both systolic and diastolic BP was recorded by auscultatory method. Out of 994 children, 480(48.29%) were boys and 514(51.71%) were girls. In boys, the mean±SD of systolic and diastolic blood pressure (BP) were 105.9±10.8 mm of Hg and 67.4±6.7 mm of Hg and in girls it was 106.1±11.8 and 67.5±6.9 mm of Hg respectively. Systolic BP was found higher in girls belongs to 10-13 years. The study has shown that BP rises linearly with age and both systolic and diastolic BP has a significant positive correlation with age, sex, height and BMI in both sexes. This study also showed, 46(4.6%) children were hypertensive and 89(8.9%) were pre-hypertensive. Hypertension was found more in girls but there was no significant difference between two sexes. Hypertension was found more in relation to overweight, obesity and family history of hypertension. Hypertension is not uncommon in children. Routine blood pressure measurement should be conducted in all children.
Assuntos
Hipertensão , Masculino , Feminino , Adolescente , Humanos , Criança , Pressão Sanguínea/fisiologia , Estudos Transversais , Hipertensão/epidemiologia , Obesidade , Sobrepeso , Índice de Massa CorporalRESUMO
AIM: To analyse the effect of wet heat treatment on nutrient and non-nutrient germination of individual spores of Clostridium perfringens. METHODS AND RESULTS: Raman spectroscopy and differential interference contrast (DIC) microscopy were used to monitor the dynamic germination of individual untreated and wet heat-treated spores of Cl. perfringens with various germinants. When incubated in water at 90-100°C for 10-30 min, more than 90% of spores were inactivated but 50-80% retained their Ca(2+) -dipicolinic acid (CaDPA). The wet heat-treated spores that lost CaDPA exhibited extensive protein denaturation as seen in the 1640-1680 cm(-1) (amide I) and 1230-1340 cm(-1) (amide III) regions of Raman spectra, while spores that retained CaDPA showed partial protein denaturation. Wet heat-treated spores that retained CaDPA germinated with KCl or l-asparagine, but wet heat treatment increased values of T(lag) , ΔT(release) and ΔT(lys) , during which spores initiated release of the majority of their CaDPA after mixing with germinant, released >90% of their CaDPA and completed the decrease in their DIC intensity because of cortex hydrolysis, respectively. Untreated Cl. perfringens spores lacking the essential cortex-lytic enzyme (CLE), SleC, exhibited longer T(lag) and ΔT(release) values during KCl germination than wild-type spores and germinated poorly with CaDPA. Wet heat-treated wild-type spores germinating with CaDPA or dodecylamine exhibited increased T(lag) , ΔT(release) and ΔT(lys) values, as did wet heat-treated sleC spores germinating with dodecylamine. CONCLUSIONS: (i) Some proteins important in Cl. perfringens spore germination are damaged by wet heat treatment; (ii) the CLE SleC or the serine protease CspB that activates SleC might be germination proteins damaged by wet heat; and (iii) the CaDPA release process seems likely to be damaged by wet heat. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides information on the germination of individual Cl. perfringens spores and improves the understanding of effects of wet heat treatment on spores.
Assuntos
Clostridium perfringens/fisiologia , Temperatura Alta , Água/metabolismo , Aminas/metabolismo , Asparagina/metabolismo , Proteínas de Bactérias/metabolismo , Hidrólise , Viabilidade Microbiana , Microscopia de Interferência , Ácidos Picolínicos/metabolismo , Desnaturação Proteica , Análise Espectral Raman , Esporos Bacterianos/fisiologiaRESUMO
AIMS: To analyse the germination and its heterogeneity of individual spores of Clostridium perfringens. METHODS AND RESULTS: Germination of individual wild-type Cl. perfringens spores was followed by monitoring Ca-dipicolinic acid (CaDPA) release and by differential interference contrast (DIC) microscopy. Following the addition of KCl that acts via germinant receptors (GRs), there was a long variable lag period (T(lag)) with slow release of c. 25% of CaDPA, then rapid release of remaining CaDPA in c. 2 min (ΔT(release)) and a parallel decrease in DIC image intensity, and a final decrease of c. 25% in DIC image intensity during spore cortex hydrolysis. Spores lacking the essential cortex-lytic enzyme (CLE) (sleC spores) exhibited the same features during GR-dependent germination, but with longer average T(lag) values, and no decrease in DIC image intensity because of cortex hydrolysis after full CaDPA release. The T(lag) of wild-type spores in KCl germination was increased significantly by lower germinant concentrations and suboptimal heat activation. Wild-type and sleC spores had identical average T(lag) and ΔT(release) values in dodecylamine germination that does not utilize GRs. CONCLUSIONS: Most of these results were essentially identical to those reported for the germination of individual spores of Bacillus species. However, individual sleC Cl. perfringens spores germinated inefficiently with either KCl or exogenous CaDPA, in contrast to CLE-deficient Bacillus spores, indicating that germination of these species' spores is not completely identical. SIGNIFICANCE AND IMPACT OF THE STUDY: This work provides information on the kinetic germination and its heterogeneity of individual spores of Cl. perfringens.
Assuntos
Clostridium perfringens/fisiologia , Esporos Bacterianos/fisiologia , Bacillus/fisiologia , Temperatura Alta , Hidrólise , Microscopia de Interferência , Ácidos Picolínicos/farmacologia , Cloreto de Potássio/farmacologiaRESUMO
SETTING: Tuberculosis (TB) program, Damien Foundation Projects, Bangladesh. OBJECTIVE: To summarize the outcome and its determinants of the first treatment for multidrug-resistant TB using a standardized regimen consisting of a minimum 9 months. DESIGN: This was a prospective, observational study of a gatifloxacin (GFX) based directly observed regimen, mainly with initial hospitalization. The 4-month intensive phase was extended until sputum smear conversion. Patients were monitored using culture for up to 2 years after treatment completion. RESULTS: Of the 515 patients who met the study inclusion criteria and were successively enrolled from 2005 to 2011, 84.4% had a bacteriologically favorable outcome. Due to extensive disease with delayed sputum conversion, only half of the patients completed treatment within 9 months; however, 95% were able to complete treatment within 12 months. Eleven patients failed or relapsed, and 93.1% of the 435 patients who were successfully treated completed at least 12 months post-treatment follow-up. The strongest risk factor for a bacteriologically unfavorable outcome was high-level fluoroquinolone (FQ) resistance, particularly when compounded by initial pyrazinamide (PZA) resistance. Low-level FQ resistance had no unfavorable effect on treatment outcome. Amplification of drug resistance occurred only once, in a patient strain that was initially only susceptible to kanamycin and clofazimine. CONCLUSION: The excellent outcome of the Bangladesh regimen was largely maintained. Bacteriological treatment failures and relapses were rare, except among patients with high-level GFX resistance, notably in the presence of PZA resistance.
Assuntos
Antibacterianos/uso terapêutico , Fluoroquinolonas/uso terapêutico , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Adolescente , Adulto , Idoso , Bangladesh , Criança , Clofazimina/uso terapêutico , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana Múltipla , Feminino , Seguimentos , Gatifloxacina , Humanos , Canamicina/uso terapêutico , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Mycobacterium tuberculosis/efeitos dos fármacos , Estudos Prospectivos , Pirazinamida/uso terapêutico , Fatores de Risco , Escarro/microbiologia , Resultado do Tratamento , Adulto JovemRESUMO
To develop a spore inactivation strategy, the effect of 15-min hydrostatic pressure treatments (550 and 650 MPa) at 55 and 75 degrees C in citric acid buffer (4.75 and 6.5 pH) on spores of 5 isolates of Clostridium perfringens type A carrying the gene that encodes the C. perfringens enterotoxin (cpe) on the chromosome (C-cpe), 4 isolates carrying the cpe gene on a plasmid (P-cpe), and 2 strains of C. sporogenes were investigated. Treatments at 650 MPa, 75 degrees C and pH 6.5 were moderately effective against spores of P-cpe (approximately 3.7 decimal reduction, DR) and C. sporogenes (approximately 2.1 DR) but not for C-cpe (approximately 1.0 DR) spores. Treatments at pH 4.75 were moderately effective against spores of P-cpe (approximately 3.2 DR) and C. sporogenes (approximately 2.5 DR) but not of C-cpe (approximately 1.2 DR) when combined with 550 MPa at 75 degrees C. However, when pressure was raised to 650 MPa under the same conditions, high inactivation of P-cpe (approximately 5.1 DR) and C. sporogenes (approximately 5.8 DR) spores and moderate inactivation of C-cpe (approximately 2.8 DR) spores were observed. Further advances in high-pressure treatment strategies to inactivate spores of cpe-positive C. perfringens type A and C. sporogenes more efficiently are needed.
Assuntos
Clostridium perfringens/fisiologia , Clostridium/fisiologia , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Conservação de Alimentos/métodos , Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Concentração de Íons de Hidrogênio , Pressão Hidrostática , Esporos Bacterianos , Temperatura , Fatores de TempoRESUMO
Transformation of pBR322 DNA into Shigella occurred at a low frequency. The efficiency of transformation was highest in S. dysenteriae 1 and lowest in S. flexneri. Treatment of cells with CaCl2 for a prolonged period (24h) increased the efficiency of transformation in all strains, except in S. flexneri, where transformation efficiency could not be improved by a variety of manipulations. Transformation efficiency did not increase in any of the strains when transformation was carried out with plasmid DNA obtained from a transformant (homologous transformation), suggesting the absence of a strong restriction-modification system. Extracellular deoxyribonuclease (DNase) levels were low in all the strains tested, but the levels of endogenous DNAse, released after CaCl2 treatment or sonication of the cells, were high. Washing the cells with a solution of CaCl2 did not enhance transformation, suggesting that endogenous DNase could be a significant factor affecting transformation efficiency in species of Shigella.
Assuntos
Shigella/genética , Transformação Genética , DNA Bacteriano/genética , Desoxirribonucleases/metabolismo , Íons , Plasmídeos , Protaminas/farmacologia , Shigella/enzimologia , Shigella/crescimento & desenvolvimento , Especificidade da Espécie , Transformação Genética/efeitos dos fármacosRESUMO
Gene transfer in seven pathogenic enteric bacteria was studied using an RP4: :mini-Mu element, the plasmid pULB113. From the E. coli K-12 host strain the plasmid could be efficiently transferred to these enteric bacteria, but its transfer back to E. coli K-12 was not as efficient, being detected only in Shigella dysenteriae 1, S. flexneri and the 'smooth' variant of S. sonnei. In these three species, transposition of chromosomal fragments into the plasmid to produce R-prime plasmid was also detected at a frequency of approximately 10(-5). Transposition was random as suggested by the recovery at approximately the same frequency (10(-5) to 10(-6)) of R-primes involving 20 different auxotrophic markers from widely separated chromosomal locations. Formation of R-prime plasmids expressing toxicity in the E. coli K-12 recipient strain was also efficient in S. dysenteriae 1 but the toxin-activity was rapidly lost from these R-primes. In our experiments, the plasmid pULB113 incorporated relatively small amounts of chromosomal DNA as determined by restriction endonuclease digestion. For a Thy+ R-prime that we analyzed, the amount of cloned DNA was approximately 15 kb.
Assuntos
Escherichia coli/genética , Fatores R/genética , Shigella/genética , Transfecção/genética , Vibrio cholerae/genética , DNA/análise , Enzimas de Restrição do DNARESUMO
As an approach to the development of attenuated strains, thymine-requiring (Thy-) and temperature-sensitive (Ts-) single and double mutants of Shigella flexneri Y have been isolated by u.v. mutagenesis and selection. The mutants retained the 140 MDa plasmid, were Sereny-negative and avirulent in 'conditioned' rabbits and in monkeys. Rabbits and monkeys immunized orally with two doses of the mutants were solidly protected against disease and lethality when challenged with the homologous virulent strain. The immunized animals had higher levels of antibodies reactive to the lipopolysaccharide of the wild type strain and also a shorter duration of shedding of the challenge bacteria. It was concluded that Thy- and Ts- mutants of Shigella spp. are highly attenuated and immunogenic to be considered for further studies towards the development of vaccine candidates.
Assuntos
Vacinas Bacterianas/imunologia , Disenteria Bacilar/prevenção & controle , Shigella flexneri/imunologia , Timina/metabolismo , Administração Oral , Animais , Vacinas Bacterianas/administração & dosagem , Disenteria Bacilar/imunologia , Eletroforese em Gel de Poliacrilamida , Lipopolissacarídeos/imunologia , Macaca mulatta/imunologia , Mutação , Coelhos , Shigella flexneri/genética , Shigella flexneri/metabolismo , TemperaturaRESUMO
Most (about 81%) of the clinical isolates of shigellae that were tested failed to grow in a minimal medium. Of the auxotrophic isolates belonging to the four Shigella species, 98% grew in a minimal medium containing methionine, nicotinic acid, and tryptophan. The combination of methionine and tryptophan appears to be an obligatory requirement for Shigella dysenteriae serotype 1 strains, while the combination of nicotinic acid and tryptophan appears to be obligatory for serotype 2. Requirements which varied in other isolates were, however, genetically stable, indicating that the auxotypes may be useful as epidemiological markers. Cultures of shigellae in liquid minimal medium containing the above three supplements showed rapid growth and gave reasonably high cell yields.
Assuntos
Shigella/crescimento & desenvolvimento , Ágar , Meios de Cultura , Metionina/metabolismo , Niacina/metabolismo , Sorotipagem , Shigella/classificação , Triptofano/metabolismoRESUMO
Previous epidemiological studies have implicated Clostridium perfringens enterotoxin (CPE) as a virulence factor in the pathogenesis of several gastrointestinal (GI) illnesses caused by C. perfringens type A isolates, including C. perfringens type A food poisoning and non-food-borne GI illnesses, such as antibiotic-associated diarrhoea and sporadic diarrhoea. To further evaluate the importance of CPE in the pathogenesis of these GI diseases, allelic exchange was used to construct cpe knock-out mutants in both SM101 (a derivative of a C. perfringens type A food poisoning isolate carrying a chromosomal cpe gene) and F4969 (a C. perfringens type A non-food-borne GI disease isolate carrying a plasmid-borne cpe gene). Western blot analyses confirmed that neither cpe knock-out mutant could express CPE during either sporulation or vegetative growth, and that this lack of CPE expression could be complemented by transforming these mutants with a recombinant plasmid carrying the wild-type cpe gene. When the virulence of the wild-type, mutant and complementing strains were compared in a rabbit ileal loop model, sporulating (but not vegetative) culture lysates of the wild-type isolates induced significant ileal loop fluid accumulation and intestinal histopathological damage, but neither sporulating nor vegetative culture lysates of the cpe knock-out mutants induced these intestinal effects. However, full sporulation-associated virulence could be restored by complementing these cpe knock-out mutants with a recombinant plasmid carrying the wild-type cpe gene, which confirms that the observed loss of virulence for the cpe knock-out mutants results from the specific inactivation of the cpe gene and the resultant loss of CPE expression. Therefore, in vivo analysis of our isogenic cpe mutants indicates that CPE expression is necessary for these two cpe-positive C. perfringens type A human disease isolates to cause GI effects in the culture lysate:ileal loop model system, a finding that supports CPE as an important virulence factor in GI diseases involving cpe-positive C. perfringens type A isolates.
Assuntos
Toxinas Bacterianas/genética , Proteínas de Ligação ao Cálcio , Clostridium perfringens/patogenicidade , Enterotoxinas/genética , Gastroenteropatias/microbiologia , Íleo/microbiologia , Fosfolipases Tipo C/genética , Animais , Toxinas Bacterianas/metabolismo , Southern Blotting , Clostridium perfringens/genética , Feminino , Doenças Transmitidas por Alimentos/microbiologia , Regulação Bacteriana da Expressão Gênica , Teste de Complementação Genética , Humanos , Íleo/patologia , Masculino , Mutação , Reação em Cadeia da Polimerase , Coelhos , Especificidade da Espécie , Fosfolipases Tipo C/metabolismo , Virulência/genéticaRESUMO
Clostridium perfringens enterotoxin is the major virulence factor involved in the pathogenesis of C. perfringens type A food poisoning and several non-food-borne human gastrointestinal illnesses. The enterotoxin gene, cpe, is located on the chromosome of food-poisoning isolates but is found on a large plasmid in non-food-borne gastrointestinal disease isolates and in veterinary isolates. To evaluate whether the cpe plasmid encodes its own conjugative transfer, a C. perfringens strain carrying pMRS4969, a plasmid in which a 0.4-kb segment internal to the cpe gene had been replaced by the chloramphenicol resistance gene catP, was used as a donor in matings with several cpe-negative C. perfringens isolates. Chloramphenicol resistance was transferred at frequencies ranging from 2.0 x 10(-2) to 4.6 x 10(-4) transconjugants per donor cell. The transconjugants were characterized by PCR, pulsed-field gel electrophoresis, and Southern hybridization analyses. The results demonstrated that the entire pMRS4969 plasmid had been transferred to the recipient strain. Plasmid transfer required cell-to-cell contact and was DNase resistant, indicating that transfer occurred by a conjugation mechanism. In addition, several fragments of the prototype C. perfringens tetracycline resistance plasmid, pCW3, hybridized with pMRS4969, suggesting that pCW3 shares some similarity to pMRS4969. The clinical significance of these findings is that if conjugative transfer of the cpe plasmid occurred in vivo, it would have the potential to convert cpe-negative C. perfringens strains in normal intestinal flora into strains capable of causing gastrointestinal disease.
Assuntos
Clostridium perfringens/genética , Conjugação Genética , Enterotoxinas/genética , Plasmídeos , Clostridium perfringens/patogenicidade , Enterotoxinas/toxicidade , Doenças Transmitidas por Alimentos/etiologia , HumanosRESUMO
Clostridium perfringens type A isolates producing enterotoxin (CPE) are an important cause of food poisoning and non-food-borne human gastrointestinal (GI) diseases, including antibiotic-associated diarrhea (AAD). Recent studies suggest that C. perfringens type A food poisoning is caused by C. perfringens isolates carrying a chromosomal cpe gene, while CPE-associated non-food-borne GI diseases, such as AAD, are caused by plasmid cpe isolates. Those putative relationships, obtained predominantly with European isolates, were tested in the current study by examining 34 cpe-positive, C. perfringens fecal isolates from North American cases of food poisoning or AAD. These North American disease isolates were all classified as type A using a multiplex PCR assay. Furthermore, restriction fragment length polymorphism and pulsed-field gel electrophoresis genotyping analyses showed the North American AAD isolates included in this collection all have a plasmid cpe gene, but the North American food poisoning isolates all carry a chromosomal cpe gene. Western blotting demonstrated CPE expression by nearly all of these disease isolates, confirming their virulence potential. These findings with North American isolates provide important new evidence that, regardless of geographic origin or date of isolation, plasmid cpe isolates cause most CPE-associated AAD cases and chromosomal cpe isolates cause most C. perfringens type A food poisoning cases. These findings hold importance for the development of assays for distinguishing cases of CPE-associated food-borne and non-food-borne human GI illnesses and also identify potential epidemiologic tools for determining the reservoirs for these illnesses.
Assuntos
Clostridium perfringens/classificação , Clostridium perfringens/genética , Diarreia/microbiologia , Fezes/microbiologia , Doenças Transmitidas por Alimentos/microbiologia , Antibacterianos/efeitos adversos , Western Blotting , Cromossomos Bacterianos/genética , Infecções por Clostridium/microbiologia , Clostridium perfringens/isolamento & purificação , Diarreia/etiologia , Eletroforese em Gel de Campo Pulsado , Enterotoxinas/genética , Enterotoxinas/metabolismo , Genótipo , Humanos , América do Norte , Plasmídeos/genética , Reação em Cadeia da Polimerase/métodos , Polimorfismo de Fragmento de RestriçãoRESUMO
LcrV, an essential piece of the Yop virulon, is encoded by the large lcrGVsycDyopBD operon. In spite of repeated efforts, the role of LcrV in the Yop virulon remains elusive. In an attempt to clarify this, we engineered a complete deletion of lcrV in the pYV plasmid of Yersinia enterocolitica E40 and characterized the phenotype of the mutant. Complementation experiments showed that the mutation was not polar with regard to yopB and yopD. Nevertheless the mutation abolished secretion of YopB and YopD, while secretion of the other Yops was unaffected or even increased. Northern blot analysis showed that transcription of yopD was not affected. YopD could be detected inside the bacteria, showing that the lack of its secretion was not due to a lack of translation or to proteolysis. This indicated that LcrV is specifically involved in the process of release of YopB and YopD. We then investigated the possible interactions between LcrV and YopB or YopD. We constructed a glutathione S-transferase-LcrV hybrid protein, and we observed that either YopB or YopD could be copurified with it. The same approach showed that LcrV also interacts with LcrG but not with the chaperone SycD. Using deletants of lcrV, we then identified a definite LcrG-binding domain in the C terminus of LcrV.
Assuntos
Antígenos de Bactérias/metabolismo , Proteínas da Membrana Bacteriana Externa/metabolismo , Plasmídeos , Yersinia enterocolitica/patogenicidade , Antígenos de Bactérias/química , Antígenos de Bactérias/genética , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Transporte Biológico , Óperon , Proteínas Citotóxicas Formadoras de Poros , Proteínas Recombinantes de Fusão/metabolismo , Deleção de Sequência , Transcrição Gênica , Virulência , Yersinia enterocolitica/genética , Yersinia enterocolitica/metabolismoRESUMO
The complete nucleotide sequence of the gene (leuB) coding for beta-isopropylmalate dehydrogenase of Bacteroides fragilis was determined. An open reading frame of 1,061 nucleotides was detected that could encode a polypeptide of 353 amino acid residues with a calculated molecular mass of 39,179 Da. The deduced amino acid sequence of the beta-isopropylmalate dehydrogenase from B. fragilis showed substantial sequence similarity with the beta-isopropylmalate dehydrogenases from other bacteria.
Assuntos
Oxirredutases do Álcool/genética , Bacteroides fragilis/enzimologia , Genes Bacterianos , 3-Isopropilmalato Desidrogenase , Sequência de Aminoácidos , Bacteroides fragilis/genética , Sequência de Bases , Dados de Sequência Molecular , Peso Molecular , Fases de Leitura Aberta/genética , Homologia de Sequência de AminoácidosRESUMO
Clones containing the Bacteroides fragilis leuB-complementing gene were isolated by screening of a B. fragilis genomic library constructed in Escherichia coli. One recombinant clone, designated pOT865, with the smallest DNA insert (4.5 kb) could complement three independent leuB mutations in E. coli and the leuB-complementing determinant in pOT865 was localized to a region of 1.5-kb DNA. The results of Southern blot analysis suggested that a single copy of the cloned gene was present in the B. fragilis genome. The cloned fragment appeared to contain a sequence that could function as promoter in E. coli and direct the synthesis of a 42-kDa protein. These results suggest that the cloned segment contains the structural gene for beta-isopropylmalate dehydrogenase (leuB).
Assuntos
Oxirredutases do Álcool/genética , Bacteroides fragilis/genética , Genes Bacterianos/genética , 3-Isopropilmalato Desidrogenase , Oxirredutases do Álcool/biossíntese , Bacteroides fragilis/enzimologia , Southern Blotting , Clonagem Molecular , Escherichia coli/genética , Teste de Complementação Genética , Biblioteca Genômica , Leucina/biossíntese , Regiões Promotoras Genéticas/genética , Proteínas Recombinantes/biossíntese , Mapeamento por RestriçãoRESUMO
Extracellular Yersinia disables the immune system of its host by injecting effector Yop proteins into host cells. We show that a Yersinia enterocolitica nonpolar lcrG mutant is severely impaired in the translocation of YopE, YopH, YopM, YpkA/YopO, and YopP into eukaryotic cells. LcrG is thus required for efficient internalization of all the known Yop effectors.
Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Bactérias/metabolismo , Yersinia enterocolitica/patogenicidade , Proteínas de Bactérias/genética , Toxinas Bacterianas/metabolismo , Transporte Biológico , Citotoxinas/metabolismo , Células Eucarióticas/microbiologia , Células HeLa/microbiologia , Humanos , Macrófagos/microbiologia , Mutação , Proteínas Citotóxicas Formadoras de Poros , Proteínas Tirosina Fosfatases/metabolismo , Yersinia enterocolitica/genética , Yersinia enterocolitica/metabolismoRESUMO
Clostridium perfringens enterotoxin (CPE) is an important virulence factor for both C. perfringens type A food poisoning and several non-food-borne human gastrointestinal diseases. Recent studies have indicated that C. perfringens isolates associated with food poisoning carry a chromosomal cpe gene, while non-food-borne human gastrointestinal disease isolates carry a plasmid cpe gene. However, no explanation has been provided for the strong associations between certain cpe genotypes and particular CPE-associated diseases. Since C. perfringens food poisoning usually involves cooked meat products, we hypothesized that chromosomal cpe isolates are so strongly associated with food poisoning because (i) they are more heat resistant than plasmid cpe isolates, (ii) heating induces loss of the cpe plasmid, or (iii) heating induces migration of the plasmid cpe gene to the chromosome. When we tested these hypotheses, vegetative cells of chromosomal cpe isolates were found to exhibit, on average approximately twofold-higher decimal reduction values (D values) at 55 degrees C than vegetative cells of plasmid cpe isolates exhibited. Furthermore, the spores of chromosomal cpe isolates had, on average, approximately 60-fold-higher D values at 100 degrees C than the spores of plasmid cpe isolates had. Southern hybridization and CPE Western blot analyses demonstrated that all survivors of heating retained their cpe gene in its original plasmid or chromosomal location and could still express CPE. These results suggest that chromosomal cpe isolates are strongly associated with food poisoning, at least in part, because their cells and spores possess a high degree of heat resistance, which should enhance their survival in incompletely cooked or inadequately warmed foods.