Background: Donated blood contaminated with S. Typhi can cause post-transfusion sepsis. This study aimed to determine the correlation between some risk factors of typhoid fever and seroprevalence of antibodies against...Background: Donated blood contaminated with S. Typhi can cause post-transfusion sepsis. This study aimed to determine the correlation between some risk factors of typhoid fever and seroprevalence of antibodies against S. Typhi among blood donors. Methodology: Following informed consent, socio-demographic and information on risk factors of typhoid infection was obtained using pre-structured questionnaires from 400 apparently healthy blood donors at the Tema General Hospital. Blood was also collected for serology and cultured for identification of pathogens by standard bacteriological method. Results: Blood culture did not reveal any S. Typhi isolate out of the tested 400 (348 males and 52 females) samples from apparently healthy blood donors. However, IgM and IgG antibody seroprevalence of 9.3% and 3.5% were detected. Age group of 17 - 24 years was the highest risk group, persons with a history of typhoid infection, and sources of drinking water were major risk factors for typhoid infection. It was also observed that prevalence of IgM was highest among new donors (62.2%), but lower in donors with a history of 1 to 3 blood donations (32.4%) and least among regular donors (>3 donations (5.4%)). In addition, typhoid prevention awareness and typhoid knowledge (knowledge about typhoid transmission) among the donors were poor (4.3% and 5.9% respectively). Conclusions: This study has shown an overall seroprevalence of 9% and 3.5% for IgM and IgG antibodies respectively among blood donors in the Tema area in Ghana. We advocate for the mandatory screening of donor units intended for transfusion for S. Typhi. Furthermore, there is an urgent need for the health education of all persons in Ghana on preventive measures and the spread of S. Typhi.展开更多
Shigella species cause severe bacillary dysentery in humans and are associated with high morbidity and mortality. The Invasion plasmid antigen （IpaB） protein, which is conserved across all Shigella spp., induces mac...Shigella species cause severe bacillary dysentery in humans and are associated with high morbidity and mortality. The Invasion plasmid antigen （IpaB） protein, which is conserved across all Shigella spp., induces macrophage cell death and is required to invade host cells. The present study evaluates the immunogenicity and protective efficacy of the recombinant （r） domain region of IpaB （rlpaB） of S. flexneri, rlpaB was administered either alone or was co-administered with the rGroEL （heat shock protein 60） protein from S. Typhi as an adjuvant in a mouse model of intranasal immunization. The IpaB domain region （37 kDa） of S. flexneriwas amplified from an invasion plasmid, cloned, expressed in BL21 Escherichia colicells and purified. Immunization with the rlpaB domain alone stimulated both humoral and cell-mediated immune responses. Furthermore, robust antibody （IgG, IgA） and T-cell responses were induced when the rlpaB domain was co-administered with rGroEL. Antibody isotyping revealed higher IgG 1 and IgG2a antibody titers and increased interferon-gamma （IFN-γ） secretion in the co-administered group. Immunization of mice with the rlpaB domain alone protected 60%-70% of the mice from lethal infection by S. flexneri, S. boydiiand S. sonnei, whereas co-administration with rGroEL increased the protective efficacy to 80%-85%. Organ burden and histopathological studies also revealed a significant reduction in lung infection in the co-immunized mice compared with mice immunized with the rlpaB domain alone. This study emphasizes that the co-administration of the rlpaB domain and rGroEL protein improves immune responses in mice and increases protective efficacy against Shigella infection. This is also the first report to evaluate the potential of the GroEL （Hsp 60） protein of S. Typhi as an adjuvant molecule, thereby overcoming the need for commercial adjuvants.展开更多
<b>Objective:</b> Almost all year round occurrence of typhoid fever remains a major public health issue in Bangladesh. In recent years, there has been a significant rise in the prevalence of multi-drug res...<b>Objective:</b> Almost all year round occurrence of typhoid fever remains a major public health issue in Bangladesh. In recent years, there has been a significant rise in the prevalence of multi-drug resistance <i>Salmonella typhi</i> in Dhaka city. The major objective of this study was to observe the prevalence of multi-drug and Extended drug-resistant patterns of typhoidal <i>Salmonella typhi</i> among the patients attending a tertiary medical center by conventional culture and serologic test. <b>Materials and Methods:</b> Blood was collected by syringe and equally divided between aerobic & anaerobic BacT Alert bottle, 10 mL for paediatrics. Post isolation <i>Salmonella</i> strains were identified and were tested for antibiotic resistance. <b>Results:</b> A total of 600 blood samples of typhoid suspected patients were tested, where 32.5% came out positive, which were identified as <i>Salmonella typhi</i>. These isolates were susceptible to carbapenem drugs but highly resistant to Fluoroquinolones and Aminoglycosides antibiotics. <b>Discussion:</b> It was seen that 73.23% of isolates among male patients were extensively drug-resistant (XDR) meaning that isolates were sensitive against only one or two antibiotics while in the female it was 58.46%. Isolates from Female patients showed higher multi-drug resistant (MDR) (26.15%) isolates resistance to multiple antibiotics in comparison to isolates from the male (16.54%). 87.19% of the strains showed high drug resistance (XDR and MDR). <b>Conclusion:</b> The emergence of XDR and MDR strains of <i>S. typhi</i> in recent years is becoming a significant threat. Although no PAN-Drug resistance (resistant against all tested drugs) was observed in the current study, a high level of XDR and MDR isolates are indicating that the scenario might take place sooner than later.展开更多
pR_(ST98) is a large and conjugative resistant plasmid(R plasmid)of 98.6 mega-dalton from multi-drug resistant Salmonella typhi(S.typhi),which was classified to incompatibility group C(Inc C).It has been found that pR...pR_(ST98) is a large and conjugative resistant plasmid(R plasmid)of 98.6 mega-dalton from multi-drug resistant Salmonella typhi(S.typhi),which was classified to incompatibility group C(Inc C).It has been found that pR_(ST98) made its host bacteria not only antibiotic resistant but also more virulent.In this study we explored the possibility of plasmid pR_(ST98) in S.typhi carrying the Salmonella plasmid virulence gene-spv.The plasmid pR_(ST98) was isolated, purified and then digested by nine restriction endonucleases to make the plasmid enzyme profile.Spv-specific PCR and Southern blot were applied to identify the virulence gene on pR_(ST98).The amplified spv fragments spvR and spvB were cloned into pGEM-T EASY and then the DNA sequences were analysed.The fragments of pR_(ST98) digested by endonucleases Bgl Ⅱ,Pst Ⅰ and Sac Ⅱ were identified,which may be useful for molecular analysis and further epidemiological surveillance of pR_(ST98).The results of PCR and Southern blot showed that spv homologous genetic sequence which had been found in all pathogenesis Salmonella spp.except S.typhi was also presented on pR_(ST98).The ORF of spvR and spvB of pR_(ST98) were 894 bp and 1,776 bp,respectively.They have more than 99% homology with that of spvR and spvB on virulence plasmid in S.typhmurium.The genotype research on pR_(ST98) revealed that there is a plasmid carrying genes responsible for drug resistance and virulence in S.typhi.This is the first report for such kind chimerical plasmid in S.typhi.Cellular & Molecular Immunology.2005;2(2):136-140.展开更多
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 anti...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.展开更多
文摘Background: Donated blood contaminated with S. Typhi can cause post-transfusion sepsis. This study aimed to determine the correlation between some risk factors of typhoid fever and seroprevalence of antibodies against S. Typhi among blood donors. Methodology: Following informed consent, socio-demographic and information on risk factors of typhoid infection was obtained using pre-structured questionnaires from 400 apparently healthy blood donors at the Tema General Hospital. Blood was also collected for serology and cultured for identification of pathogens by standard bacteriological method. Results: Blood culture did not reveal any S. Typhi isolate out of the tested 400 (348 males and 52 females) samples from apparently healthy blood donors. However, IgM and IgG antibody seroprevalence of 9.3% and 3.5% were detected. Age group of 17 - 24 years was the highest risk group, persons with a history of typhoid infection, and sources of drinking water were major risk factors for typhoid infection. It was also observed that prevalence of IgM was highest among new donors (62.2%), but lower in donors with a history of 1 to 3 blood donations (32.4%) and least among regular donors (>3 donations (5.4%)). In addition, typhoid prevention awareness and typhoid knowledge (knowledge about typhoid transmission) among the donors were poor (4.3% and 5.9% respectively). Conclusions: This study has shown an overall seroprevalence of 9% and 3.5% for IgM and IgG antibodies respectively among blood donors in the Tema area in Ghana. We advocate for the mandatory screening of donor units intended for transfusion for S. Typhi. Furthermore, there is an urgent need for the health education of all persons in Ghana on preventive measures and the spread of S. Typhi.
文摘Shigella species cause severe bacillary dysentery in humans and are associated with high morbidity and mortality. The Invasion plasmid antigen （IpaB） protein, which is conserved across all Shigella spp., induces macrophage cell death and is required to invade host cells. The present study evaluates the immunogenicity and protective efficacy of the recombinant （r） domain region of IpaB （rlpaB） of S. flexneri, rlpaB was administered either alone or was co-administered with the rGroEL （heat shock protein 60） protein from S. Typhi as an adjuvant in a mouse model of intranasal immunization. The IpaB domain region （37 kDa） of S. flexneriwas amplified from an invasion plasmid, cloned, expressed in BL21 Escherichia colicells and purified. Immunization with the rlpaB domain alone stimulated both humoral and cell-mediated immune responses. Furthermore, robust antibody （IgG, IgA） and T-cell responses were induced when the rlpaB domain was co-administered with rGroEL. Antibody isotyping revealed higher IgG 1 and IgG2a antibody titers and increased interferon-gamma （IFN-γ） secretion in the co-administered group. Immunization of mice with the rlpaB domain alone protected 60%-70% of the mice from lethal infection by S. flexneri, S. boydiiand S. sonnei, whereas co-administration with rGroEL increased the protective efficacy to 80%-85%. Organ burden and histopathological studies also revealed a significant reduction in lung infection in the co-immunized mice compared with mice immunized with the rlpaB domain alone. This study emphasizes that the co-administration of the rlpaB domain and rGroEL protein improves immune responses in mice and increases protective efficacy against Shigella infection. This is also the first report to evaluate the potential of the GroEL （Hsp 60） protein of S. Typhi as an adjuvant molecule, thereby overcoming the need for commercial adjuvants.
文摘<b>Objective:</b> Almost all year round occurrence of typhoid fever remains a major public health issue in Bangladesh. In recent years, there has been a significant rise in the prevalence of multi-drug resistance <i>Salmonella typhi</i> in Dhaka city. The major objective of this study was to observe the prevalence of multi-drug and Extended drug-resistant patterns of typhoidal <i>Salmonella typhi</i> among the patients attending a tertiary medical center by conventional culture and serologic test. <b>Materials and Methods:</b> Blood was collected by syringe and equally divided between aerobic & anaerobic BacT Alert bottle, 10 mL for paediatrics. Post isolation <i>Salmonella</i> strains were identified and were tested for antibiotic resistance. <b>Results:</b> A total of 600 blood samples of typhoid suspected patients were tested, where 32.5% came out positive, which were identified as <i>Salmonella typhi</i>. These isolates were susceptible to carbapenem drugs but highly resistant to Fluoroquinolones and Aminoglycosides antibiotics. <b>Discussion:</b> It was seen that 73.23% of isolates among male patients were extensively drug-resistant (XDR) meaning that isolates were sensitive against only one or two antibiotics while in the female it was 58.46%. Isolates from Female patients showed higher multi-drug resistant (MDR) (26.15%) isolates resistance to multiple antibiotics in comparison to isolates from the male (16.54%). 87.19% of the strains showed high drug resistance (XDR and MDR). <b>Conclusion:</b> The emergence of XDR and MDR strains of <i>S. typhi</i> in recent years is becoming a significant threat. Although no PAN-Drug resistance (resistant against all tested drugs) was observed in the current study, a high level of XDR and MDR isolates are indicating that the scenario might take place sooner than later.
文摘pR_(ST98) is a large and conjugative resistant plasmid(R plasmid)of 98.6 mega-dalton from multi-drug resistant Salmonella typhi(S.typhi),which was classified to incompatibility group C(Inc C).It has been found that pR_(ST98) made its host bacteria not only antibiotic resistant but also more virulent.In this study we explored the possibility of plasmid pR_(ST98) in S.typhi carrying the Salmonella plasmid virulence gene-spv.The plasmid pR_(ST98) was isolated, purified and then digested by nine restriction endonucleases to make the plasmid enzyme profile.Spv-specific PCR and Southern blot were applied to identify the virulence gene on pR_(ST98).The amplified spv fragments spvR and spvB were cloned into pGEM-T EASY and then the DNA sequences were analysed.The fragments of pR_(ST98) digested by endonucleases Bgl Ⅱ,Pst Ⅰ and Sac Ⅱ were identified,which may be useful for molecular analysis and further epidemiological surveillance of pR_(ST98).The results of PCR and Southern blot showed that spv homologous genetic sequence which had been found in all pathogenesis Salmonella spp.except S.typhi was also presented on pR_(ST98).The ORF of spvR and spvB of pR_(ST98) were 894 bp and 1,776 bp,respectively.They have more than 99% homology with that of spvR and spvB on virulence plasmid in S.typhmurium.The genotype research on pR_(ST98) revealed that there is a plasmid carrying genes responsible for drug resistance and virulence in S.typhi.This is the first report for such kind chimerical plasmid in S.typhi.Cellular & Molecular Immunology.2005;2(2):136-140.
文摘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.
