Optimizing factors for the efficient expression and purification of spao and lamb from Salmonella typhi

We optimized the expression and purification of outer membrane proteins SpaO and LamB from Salmonella typhi. We investigated various factors in the expression and purification processes, including the use of isopropyl ß-d-1 thiogalactopyranoside (IPTG), imidazole, and urea. First, PCR amplification was carried out on SpaO and LamB genes. The genes were then cloned in pTZ57R/T, and then expressed in pET28a vector and transformed into Escherichia coli BL21 (DE3). Gene insertion was confirmed by enzymatic digestion with NdeI and XhoI. Inclusion bodies expressing recombinant SpaO and LamB were induced with 200 and 400 µL 0.5 mM IPTG, respectively. The formed protein inclusion bodies were then isolated from the pellet and solubilized in IB buffer containing 8 M urea for SpaO and 6 M urea for LamB. Proteins were refolded by dialysis in 3M urea. Purified proteins with nickel-nitrilotriacetic acid affinity chromatography and eluted with buffer containing 250 mM imidazole for SpaO and 150 mM imidazole for LamB. The protein expression profiles were analyzed by SDS-PAGE, which identified the 33 and 49 kDa bands corresponding to rSpaO and rLamB. Western blotting Purification was carried out by nickel affinity resin with 250 mM and 150 mM imidazole for rSpaO and rLamB and refolded through stepwise dialysis with anti-His tag antibodies confirmed their expression. These optimized methods can be used to generate recombinant proteins for the development of future vaccines.

Neuroretinitis following typhoid fever in a 55-year-old female: Case report

@#Neuroretinitis (NR) is an inflammation of the optic nerve and the neural retina. NR is diagnosed clinically, and it is characterized by blurring of vision (BOV), optic disc swelling, and macular star exudates. Spontaneous resolution of NR is possible, but corticosteroids help in hastening recovery. Rarely, Salmonella typhi infection may produce an immune-mediated reaction that can cause NR. Immune-mediated retinitis occurs 3 to 6 weeks after the febrile period of a typhoid infection. We present the case of a 55-year-old female with a two-week history of painless, unilateral BOV occurring five weeks after the initial febrile episode of a typhoid infection. A diagnosis of NR was made after fundus examination on the affected eye showed optic disc edema and macular star exudates. An eight-week course of corticosteroid treatment afforded partial resolution of the disc edema and significant reduction in the macular exudates, and improved the patient’s vision after six months.

Antibiotic resistome of Salmonella typhi: molecular determinants for the emergence of drug resistance / 医学前沿

Resistome is a cluster of microbial genes encoding proteins with necessary functions to resist the action of antibiotics. Resistome governs essential and separate biological functions to develop resistance against antibiotics. The widespread clinical and nonclinical uses of antibiotics over the years have combined to select antibiotic-resistant determinants and develop resistome in bacteria. At present, the emergence of drug resistance because of resistome is a significant problem faced by clinicians for the treatment of Salmonella infection. Antibiotic resistome is a dynamic and ever-expanding component in Salmonella. The foundation of resistome in Salmonella is laid long before; therefore, the antibiotic resistome of Salmonella is reviewed, discussed, and summarized. We have searched the literature using PubMed, MEDLINE, and Google Scholar with related key terms (resistome, Salmonella, antibiotics, drug resistance) and prepared this review. In this review, we summarize the status of resistance against antibiotics in S. typhi, highlight the seminal work in the resistome of S. typhi and the genes involved in the antibiotic resistance, and discuss the various methods to identify S. typhi resistome for the proactive identification of this infection and quick diagnosis of the disease.

Biological activity of synthesized 5-{1-[(4-chlorophenyl)sulfonyl]piperidin-4-yl}-2-mercapto-1, 3, 4-oxadiazole derivatives demonstrated by in silico and BSA binding studies

We synthesized a series of compounds bearing pharmacologically important 1,3,4-oxadiazole and piperidine moieties. Spectral data analysis by 1H-NMR, 13C-NMR, IR and EI-MS was used to elucidate the structures of the synthesized molecules. Docking studies explained the different types of interaction of the compounds with amino acids, while bovine serum albumin (BSA) binding interactions showed their pharmacological effectiveness. Antibacterial screening of these compounds demonstrated moderate to strong activity against Salmonella typhi and Bacillus subtilis but only weak to moderate activity against the other three bacterial strains tested. Seven compounds were the most active members as acetyl cholinesterase inhibitors. All the compounds presented displayed strong inhibitory activity against urease. Compounds 7l, 7m, 7n, 7o, 7p, 7r, 7u, 7v, 7x and 7v were highly active, with respective IC50 values of 2.14±0.003, 0.63±0.001, 2.17±0.006, 1.13±0.003, 1.21±0.005, 6.28±0.003, 2.39±0.005, 2.15±0.002, 2.26±0.003 and 2.14±0.002 µM, compared to thiourea, used as the reference standard (IC50 = 21.25±0.15 µM). These new urease inhibitors could replace existing drugs after their evaluation in comprehensive in vivo studies.

A Salmonella Typhi ghost induced by the E gene of phage φX174 stimulates dendritic cells and efficiently activates the adaptive immune response

Previously, we genetically engineered a Salmonella Typhi bacterial ghost (STG) as a novel inactivated vaccine candidate against typhoid fever. The underlying mechanism employed by the ghost in stimulating the adaptive immune response remains to be investigated. In this study, we aimed to evaluate the immunostimulatory effect of STG on mouse bone marrow-derived dendritic cells (BMDCs) and its activation of the adaptive immune response in vitro. Immature BMDCs were stimulated with STG, which efficiently stimulated maturation events in BMDCs, as indicated by upregulated expressions of CD40, CD80, and major histocompatibility complex class II molecules on CD11⁺ BMDCs. Immature BMDCs responded to STG stimulation by significantly increasing the expression of interleukin (IL)-6, which might indicate the induction of dendritic cell maturation in vivo (p < 0.05). In addition, ghost-stimulated murine BMDCs showed significant expressions of interferon gamma and IL-4, which can drive the development of Th1 and Th2 cells, respectively, in co-cultured CD4⁺ T cells in vitro. These results suggest that STG can effectively stimulate maturation of BMDCs and facilitate subsequent immune responses via potent immunomodulatory cytokine responses.

Absceso cerebral causado por salmonella typhi: reporte de caso / Brain abscess caused by salmonella typhi: case report

Se presenta el caso de un paciente de 50 años de edad, quien es admitido a la emergencia de adultos, con cuadro un convulsivo asociado a fiebre de una semana de evolución. El estudio de tomografía cerebral reveló la presencia de imagen heterogénea en lóbulo frontal , se interviene quirúrgicamente con hallazgo de un absceso cerebral logrando el aislamiento de Salmonella typhi, cumple cuatro semanas de tratamiento con ceftriaxona intravenosa con mejoría tanto clínica como radiológica...(AU)

We present the case of a 50-year-old patient, who is admitted to the emergency of adults, with a convulsive symptoms associated with fever of one week of evolution. The cerebral tomography study revealed the presence of heterogeneous image in the frontal lobe, it was surgically intervened with the finding of a cerebral abscess achieving the isolation of Salmonella typhi, it was four weeks of treatment with intravenous ceftriaxone with clinical and radiological improvement ... (AU )

Determinación rápida de la identidad del polisacárido de Salmonella Typhi y toxoide diftérico en vacunas conjugadas / Rapid determination of the identity of Salmonella Typhi polysaccharide and diphtheria toxoid in conjugate vaccines

El polisacárido Vi (PsVi) de Salmonella Typhi es un antígeno T-independiente y ha demostrado ser protector en adultos jóvenes. Sin embargo, para aumentar la respuesta de anticuerpos y conferir propiedades T-dependientes al polisacárido, se ha conjugado a proteínas. Dentro de los controles exigidos por los organismos regulatorios para estas vacunas está la identidad antigénica de sus componentes y para eso se recomiendan el uso de técnicas de Resonancia Magnética Nuclear o técnicas serológicas. El objetivo del presente trabajo, fue establecer las condiciones óptimas de trabajo de un Dot Blot que permitiera determinar, rápidamente, la identidad de los antígenos en vacunas conjugadas contra S. Typhi. Para ello, se estudiaron los tiempos de incubación, las concentraciones óptimas de anticuerpo monoclonal (AcM) y del ingrediente farmacéutico activo (IFA), así como los volúmenes de aplicación óptimos para las IFAs y formulaciones vacunales, tanto para el PsVi como para el toxoide diftérico (TD). Los resultados mostraron que para la determinación de la identidad antigénica fueron suficientes 5 µL de muestras de los conjugados monovalentes en una dilución de 1/10 (vol/vol) e igual volumen para las formulaciones vacunales. Quedó demostrado que la concentración de 2,5 µg/mL para el AcM contra el PsVi y a 2 µg/mL para el AcM contra TD fueron suficientes para la determinación; mientras que los tiempos de incubación fueron ajustados a 15 min con incubación a 37 ºC. Como conclusión del trabajo se puede decir que quedaron establecidas las condiciones óptimas de trabajo para la determinación rápida de la identidad antigénica del PsVi y del TD presentes en IFA y formulaciones vacunales conjugadas(AU)

Vi polysaccharide from Salmonella Typhi is a T-independent antigen that has proven to be protective in young adults. However, it has been conjugated to proteins in order to confer T-dependent properties to the polysaccharide, and improving the antibody response. The regulatory agencies require knowing the identity of antigens included in vaccines. The Nuclear Magnetic Resonance spectroscopy and serological techniques are recommended. The aim of this work was to establish the optimal working conditions of a Dot Blot that would allow to determine quickly the identity of the antigens in conjugate vaccines against S. Typhi. The incubation times, optimum concentrations of monoclonal antibodies (MAb) and active pharmaceutical ingredient (API), as well as optimum application volumes for APIs and vaccine formulations were studied for both, PsVi and diphtheria toxoid (DT). It was proven that 5 µL of samples of the monovalent conjugates were sufficient at a dilution of 1/10 (vol/vol) and an equal volume for the vaccine formulations. It was demonstrated that the concentration of 2.5 µg/mL for the MAb against PsVi and 2 µg/mL for the MAb against DT were suitable. The incubation times were adjusted to 15 min with incubation at 37 ºC. It was established a simple and rapid method for the specific identification of PsVi and DT present in API and conjugate vaccines(AU)

Differential roles for pathogenicity islands SPI-13 and SPI-8 in the interaction of Salmonella Enteritidis and Salmonella Typhi with murine and human macrophages

BACKGROUND: Salmonella pathogenicity island (SPI)-13 is conserved in many serovars of S. enterica, including S. Enteritidis, S. Typhimurium and S. Gallinarum. However, it is absent in typhoid serovars such as S. Typhi and Paratyphi A, which carry SPI-8 at the same genomic location. Because the interaction with macrophages is a critical step in Salmonella pathogenicity, in this study we investigated the role played by SPI-13 and SPI-8 in the interaction of S. Enteritidis and S. Typhi with cultured murine (RAW264.7) and human (THP-1) macrophages. RESULTS: Our results showed that SPI-13 was required for internalization of S. Enteritidis in murine but not human macrophages. On the other hand, SPI-8 was not required for the interaction of S. Typhi with human or murine macrophages. Of note, the presence of an intact copy of SPI-13 in a S. Typhi mutant carrying a deletion of SPI-8 did not improve its ability to be internalized by, or survive in human or murine macrophages. CONCLUSIONS: Altogether, our results point out to different roles for SPI-13 and SPI-8 during Salmonella infection. While SPI-13 contributes to the interaction of S. Enteritidis with murine macrophages, SPI-8 is not required in the interaction of S. Typhi with murine or human macrophages. We hypothesized that typhoid serovars have lost SPI-13 and maintained SPI-8 to improve their fitness during another phase of human infection.

Enteric Fever in a Tertiary Paediatric Hospital: A Retrospective Six-Year Review

<p><b>INTRODUCTION</b>Enteric fever is a multisystemic infection which largely affects children. This study aimed to analyse the epidemiology, clinical presentation, treatment and outcome of paediatric enteric fever in Singapore.</p><p><b>MATERIALS AND METHODS</b>A retrospective review of children diagnosed with enteric fever in a tertiary paediatric hospital in Singapore was conducted from January 2006 to January 2012. Patients with positive blood cultures for Salmonella typhi or paratyphi were identified from the microbiology laboratory information system. Data was extracted from their case records.</p><p><b>RESULTS</b>Of 50 enteric fever cases, 86% were due to Salmonella typhi, with 16.3% being multidrug resistant (MDR) strains. Sixty-two percent of S. typhi isolates were of decreased ciprofloxacin susceptibility (DCS). Five cases were both MDR and DCS. The remaining 14% were Salmonella paratyphi A. There were only 3 indigenous cases. Ninety-four percent had travelled to typhoid-endemic countries, 70.2% to the Indian subcontinent and the rest to Indonesia and Malaysia. All patients infected with MDR strains had travelled to the Indian subcontinent. Anaemia was a significant finding in children with typhoid, as compared to paratyphoid fever (P = 0.04). Although all children were previously well, 14% suffered severe complications including shock, pericardial effusion and enterocolitis. None had typhoid vaccination prior to their travel to developing countries.</p><p><b>CONCLUSION</b>Enteric fever is largely an imported disease in Singapore and has contributed to significant morbidity in children. The use of typhoid vaccine, as well as education on food and water hygiene to children travelling to developing countries, needs to be emphasised.</p>

Increased risk of depression in patients with rheumatoid arthritis: a seven-year population-based cohort study

OBJECTIVE: Rheumatoid arthritis (RA) is a costly and crippling autoimmune disease that can lead to the development of depression, contributing to suboptimal clinical outcomes. However, no longitudinal studies have identified an association between rheumatoid arthritis and subsequent depression. This study aimed to investigate the incidence and risk factors of depression among RA patients in Taiwan. METHODS: Using Taiwan's National Health Insurance Research Database, we identified 3,698 newly diagnosed RA patients aged 18 years or older, together with 7,396 subjects without RA matched by sex, age and index date, between 2000 and 2004. The incidence of depression and the risk factors among RA cases were evaluated using Cox proportional-hazard regression. RESULTS: The incidence of depression was 1.74-fold greater in the RA cohort than in the non-RA cohort (11.80 versus 6.89 per 1,000 person-years; p<0.01). Multivariate analysis showed that RA subjects who were female, were older, or had comorbidities such as stroke, chronic kidney disease, or cancer had a significantly greater risk of depression compared with those without these conditions. CONCLUSION: This population-based cohort study showed a strong relationship between RA and a subsequent risk of depression. The findings could be beneficial to healthcare providers for identifying individuals with a higher predisposition for depression, thereby possibly facilitating the provision of an appropriate rehabilitation intervention after RA onset to support the patient's adaptation. .

Surgical treatment of the osteoporotic spine with bone cement-injectable cannulated pedicle screw fixation: technical description and preliminary application in 43 patients

OBJECTIVES: To describe a new approach for the application of polymethylmethacrylate augmentation of bone cement-injectable cannulated pedicle screws. METHODS: Between June 2010 and February 2013, 43 patients with degenerative spinal disease and osteoporosis (T-score <-2.5) underwent lumbar fusion using cement-injectable cannulated pedicle screws. Clinical outcomes were evaluated using a Visual Analog Scale and the Oswestry Disability Index. Patients were given radiographic follow-up examinations after 3, 6, and 12 months and once per year thereafter. RESULTS: All patients were followed for a mean of 15.7±5.6 months (range, 6 to 35 months). The Visual Analog Scale and Oswestry Disability Index scores showed a significant reduction in back pain (p = 0.018) and an improvement in lower extremity function (p = 0.025) in patients who underwent lumbar fusion using the novel screw. Intraoperative cement leakage occurred in four patients, but no neurological complications were observed. Radiological observation indicated no loosening or pulling out of the novel screw, and bone fusion was excellent. CONCLUSIONS: The described polymethylmethacrylate augmentation technique using bone cement-injectable cannulated pedicle screws can reduce pain and improve spinal dysfunction in osteoporotic patients undergoing osteoporotic spine surgery. .

Typhoid fever with jaundice; a clinical study in Abbottabad

Typhoid fever is a systemic infection which is caused by Samonella enterica serotype typhi. It is a multi-system disorder involving many organs including liver. Liver involvement could be in the form of jaundice, rise in liver enzymes or hepatomegaly. It can present as acute hepatitis in rare cases, called typhoid hepatitis. This study was carried out to study the association of typhoid fever in patients with jaundice. To determine the frequency of typhoid fever among patients presenting with jaundice. Descriptive cross sectional study. At Gastroenterology Unit, Ayub Teaching Hospital, Abbottabad. March 2011 to December 2011. Total 115 patients were included in the study based on inclusion and exclusion criteria. Typhidot IgM test was performed to confirm the diagnosis of typhoid fever. The mean age of patients was 28.5 +/- 10.14 years, with 54.8% male gender predominating the overall sample. The male to female ratio was 1.2:1. Typhoid fever was found in 22 [19.1%] out of 115 patients with jaundice and there were 68.2% were males and 31.8% were females. Typhoid fever is not rare to present as jaundice in our part of the world where typhoid fever is endemic. Therefore, all those patients who have fever, jaundice, abnormal liver function tests or hepatomegaly must be screened for typhoid fever especially in areas where typhoid fever is endemic

stg fimbrial operon from S. Typhi STH2370 contributes to association and cell disruption of epithelial and macrophage-like cells

BACKGROUND: Salmonella enterica serovar Typhi (S. Typhi) stg operon, encoding a chaperone/usher fimbria (CU), contributes to an increased adherence to human epithelial cells. However, one report suggests that the presence of the Stg fimbria impairs the monocyte-bacteria association, as deduced by the lower level of invasion to macrophage-like cells observed when the stg fimbrial cluster was overexpressed. Nevertheless, since other CU fimbrial structures increase the entry of S. Typhi into macrophages, and considering that transcriptomic analyses revealed that stg operon is indeed expressed in macrophages, we reassessed the role of the stg operon in the interaction between S. Typhi strain STH2370 and human cells, including macrophage-like cells and mononuclear cells directly taken from human peripheral blood. RESULTS: We compared S. Typhi STH2370 WT, a Chilean clinical strain, and the S. Typhi STH2370 Astg mutant with respect to association and invasion using epithelial and macrophage-like cells. We observed that deletion of stg operon reduced the association and invasion of S. Typhi, in both cellular types. The presence of the cloned stg operon restored the WT phenotype in all the cases. Moreover, we compared Salmonella enterica sv. Typhimurium 14028s (S. Typhimurium, a serovar lacking stg operon) and S. Typhimurium heterologously expressing S. Typhi stg. We found that the latter presents an increased cell disruption of polarized epithelial cells and an increased association in both epithelial and macrophage-like cells. CONCLUSIONS: S. Typhi stg operon encodes a functional adhesin that participates in the interaction bacteria-eukary-otic cells, including epithelial cells and macrophages-like cells. The phenotypes associated to stg operon include increased association and consequent invasion in bacteria-eukaryotic cells, and cell disruption.

Rapid detection of Salmonella Typhi by loop-mediated isothermal amplification (LAMP) method

An in-house loop-mediated isothermal amplification (LAMP) reaction was established and evaluated for sensitivity and specificity in detecting the presence of Salmonella Typhi (S. Typhi) isolates from Kelantan, Malaysia. Three sets of primers consisting of two outer and 4 inner were designed based on locus STBHUCCB_38510 of chaperone PapD of S. Typhi genes. The reaction was optimised using genomic DNA of S. Typhi ATCC7251 as the template. The products were visualised directly by colour changes of the reaction. Positive results were indicated by green fluorescence and negative by orange colour. The test was further evaluated for specificity, sensitivity and application on field samples. The results were compared with those obtained by gold standard culture method and Polymerase Chain Reaction (PCR). This method was highly specific and -10 times more sensitive in detecting S. Typhi compared to the optimised conventional polymerase chain reaction (PCR) method.

In vivo antipyretic, antiemetic, in vitro membrane stabilization, antimicrobial, and cytotoxic activities of different extracts from Spilanthes paniculata leaves

BACKGROUND: The study was conducted to evaluate the in vitro antimicrobial activity, cytotoxic, and membrane stabilization activities, and in vivo antiemetic and antipyretic potentials of ethanolic extract, n-hexane and ethyl acetate soluble fractions of Spilanthes paniculata leaves for the first time widely used in the traditional treatments in Bangladesh. RESULTS: In antipyretic activity assay, a significant reduction (P < 0.05) was observed in the temperature in the mice tested. At dose 400 mg/kg-body weight, the n-hexane soluble fraction showed the effect (36.7 ± 0.63°C ) as like as the standard (dose 150 mg/kg-body weight) after 5 h of administration. Extracts showed significant (P < 0.001) potential when tested for the antiemetic activity compared to the standard, metoclopramide. At dose 50 mg/kg-body weight, the standard showed 67.23% inhibition, whereas n-hexane and ethyl acetate soluble fractions showed 37.53% and 24.93% inhibition of emesis respectively at dose 400 mg/kg-body weight. In antimicrobial activity assay, the n-hexane soluble fraction (400 µg/disc) showed salient activity against the tested organisms. It exerts highest activity against Salmonella typhi (16.9 mm zone of inhibition); besides, crude, and ethyl acetate extracts showed resistance to Bacillus cereus and Bacillus subtilis, and Vibrio cholera respectively. All the extracts were tested for lysis of the erythrocytes. At the concentration of 1mg/ml, ethanol extract, and n-hexane and ethyl acetate soluble fractions significantly inhibited hypotonic solution induced lysis of the human red blood cell (HRBC) (27.406 ± 3.57, 46.034 ± 3.251, and 30.72 ± 5.679% respectively); where standard drug acetylsalicylic acid (concentration 0.1 mg/ml) showed 77.276 ± 0.321% inhibition. In case of heat induced HRBC hemolysis, the plant extracts also showed significant activity (34.21 ± 4.72, 21.81 ± 3.08, and 27.62 ± 8.79% inhibition respectively). In the brine shrimp lethality bioassay, the n-hexane fraction showed potent (LC50 value 48.978 µg/ml) activity, whereas ethyl acetate fraction showed mild (LC50 value 216.77 µg/ml) cytotoxic activity. CONCLUSIONS: Our results showed that the n-hexane extract has better effects than the other in all trials. In the context, it can be said that the leaves of S. paniculata possess remarkable pharmacological effects, and justify its folkloric use as antimicrobial, antipyretic, anti-inflammatory, and antiemetic agent. Therefore, further research may be suggested to find possible mode of action of the plant part.

Literature Review and Clinical Presentation of Cervical Spondylitis Due to Salmonella Enteritidis in Immunocompetent

A 48-year-old woman was presented to our clinic with some fever and neck pains for about one month. Based on the symptoms and results of image, an empirical diagnosis of tuberculous cervical spondylitis was made. The pain was not significantly decreased after anti-tuberculosis therapy. And, 3 weeks later, she was re-admitted to our hospital for the unbearable pain. An exploration of the C4/5 by the anterior medial approach was recommended to evaluate the germ and debridement. Bacteriological tests showed that the pathogen was Salmonella Enteritidis. The pain was relieved significantly after operation and sensitive antibiotic treatments. Infections with Salmonella Typhi or Salmonella Paratyphi have been well-documented, while there are few reports of cervical spondylitis caused by Salmonella Enteritidis. We reported a case of a healthy woman with whom pyogenic cervical spondylitis of Salmonella Enteritidis was corroborated and treated and reviewed according to previous reports about spondylitis caused by Salmonella Enteritidis in the literature.

Non-typhoid salmonella septic arthritis in dual living liver transplant recipient: a case report

Non-typhoid salmonellosis is an infectious disease caused by Salmonella species other than Salmonella typhi. Although the usual clinical course of non-typhoid salmonellosis is a benign self-limiting gastroenteritis, these bacteria are especially problematic in immunocompromised individuals, including patients with malignancies, human immunodeficiency virus, or diabetes, and those receiving corticosteroids or other immunotherapy agents. In addition to enteric symptoms, Salmonella species give rise to extra-intestinal complications, including self-limiting arthritis, which appears 1 to 3 weeks after the onset of infection and lasts from a few weeks to several months. In some patients, however, this arthritis spears to be chronic in nature. We describe herein a living-donor liver transplant recipient who experienced non-typhoid Salmonella-triggered arthritis in the left hip. The patient recovered uneventfully after 6-month-long antibiotics treatment. Clinicians involved in transplantation should be aware of the possibility that transplant recipients, like other immunocompromised individuals, are at risk of salmonellosis and therefore require careful clinical and microbiological evaluation, with the goals of prevention and early recognition of infection.

Evaluation of Immune Response for Vi-CRM(197) Conjugated Vaccine against Salmonella enterica serovar Typhi in Mice

Typhoid fever, a serious systemic infection caused by Salmonella enterica serovar Typhi, breaks out in developing countries. However, existing vaccines only induce relatively low protective effects with humoral responses and do not stimulate secondary immune response, especially to young people. The objective of this study is to evaluate the immunogenicity of the vaccine containing virulence capsular polysaccharide (Vi) conjugated with the optimal ratios of non-toxic variant of diphtheria toxin (CRM(197)) in mice. Six-week-old BALB/c female mice were injected intraperitoneally three times at intervals of 14 days and sera were collected on days 0, 14, 28, 42 and 56 post-injection. The efficacy of the vaccine was evaluated by comparing between negative control group injected with PBS and vaccine groups injected with Vi or Vi-CRM(197) conjugate of different ratio. Vi and CRM(197)-specific antibody responses were evaluated using enzyme-linked immunosorbent assay. The result showed that Vi-CRM(197)-1 group revealed the highest and significant Vi-specific IgG immune responses among the other groups and Vi group (p < 0.01). In conclusion, Vi-CRM(197)-1 conjugate vaccine induced the highest humoral immune response in mice and may be used as an effective vaccine to replace the existing typhoid vaccine for infants under 2 years old.

Epidemiological characteristics of typhoid fever and antibiotic susceptibility testing of Salmonella Typhi isolates in Guangxi, 1994-2013 / 中华流行病学杂志

<p><b>OBJECTIVE</b>Through analyzing the typhoid epidemics and to determine and monitor regional resistance characteristics of the shift of drug resistant profile on Salmonella (S.) Typhi, to understand the related epidemiological characteristics of typhoid fever and to provide evidence for the development of strategies, in Guangxi.</p><p><b>METHODS</b>Data of typhoid fever from surveillance and reporting system between 1994 to 2013 was collected and statistically analyzed epidemiologically. The susceptibility of 475 S. Typhi isolates from patients on ten antibiotics was tested by broth micro-dilution method and minimum inhibition concentration was obtained and interpreted based on the CLSI standard.</p><p><b>RESULTS</b>From 1994 to 2013, a total of 57 928 cases of typhoid fever were reported in Guangxi province with an annual incidence of 6.29/100 000 and mortality as 0.03%. The higher incidence was observed in the population under 20 years of age. There was no significant difference on incidence between male and female, but farmers and students were among the hardest hit groups. More cases were seen from the northern part of the province. Cases appeared all year round with the peak from May to October. A total of 13 major outbreaks during 2001 to 2013 were reported and the main transmission route was water-borne. All the strains were sensitive to third generation cephalosporins cefotaxime and fluoroquinolones norfloxacin. The susceptibility rates to tetracycline, chloramphenicol, ampicillin and gentamicin was around 98% but relative lower susceptible rate to ciprofloxacin was seen as 89.89% . The lowest susceptibility was found for streptomycin and sulfamethoxazole agents, with the rates as 67.73% and 65.89% , respectively. One strain was found to have been resistant to ciprofloxacin and another 47 isolates with reduced susceptibility to ciprofloxacin. Twenty eight isolates were found to be resistant to multiple antibiotics and one displayed ampicillin, chloramphenicol, streptomycin, sulfamethoxazole tetracycline and nalidixic acid (ACSSxT-NAL) resistance profile. This was the first report in China. Multi-drug resistant strains were frequently isolated from small scale outbreaks of typhoid fever.</p><p><b>CONCLUSION</b>The incidence of typhoid fever in Guangxi was still high and some strains showed multi-drug resistance and reduced susceptibility to ciprofloxacin, indicating that the surveillance and monitor programs on drug resistance of S. Typhi should be strengthened, to prevent large scale outbreaks of typhoid fever in this province.</p>

Abceso esplénico, rara presentación de salmonela typhi / Splenic abscess, rare presentation of salmonella typhi

Absceso esplénico es una rara complicación de fiebre tifoidea. La incidencia es de 0.2 a 0.7 por ciento en estudios basados en autopsias. Existen menos de 500 casos reportados en la literatura mundial. La presentación clínica es inespecífica y es potencialmente un problema quirúrgico asociado a alta mortalidad. El tratamiento se basa en una combinación de esplenectomía total o drenaje percutáneo mas una terapia antibiótica adecuada (1,2) El absceso esplénico puede ocurrir secundario a infección del tracto urinario, apendicitis, trauma, endocarditis, neoplasia, fiebre tifoidea, embolias sépticas. Entre los microorganismos causantes más frecuentes encontramos Streptococcus, Staphylococcus, Enterobacterias. Nosotros reportamos un caso de absceso esplénico con documentación microbiológica de Salmonella typhi como agente causal.