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Aleksandra A Zasada - One of the best experts on this subject based on the ideXlab platform.
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changes in mlst profiles and biotypes of corynebacterium diphtheriae isolates from the diphtheria outbreak period to the period of invasive infections caused by Nontoxigenic Strains in poland 1950 2016
BMC Infectious Diseases, 2018Co-Authors: Urszula Czajka, Aldona Wiatrzyk, Ewa Mosiej, Kamila Formińska, Aleksandra A ZasadaAbstract:Corynebacterium diphtheriae is a re-emerging pathogen in Europe causing invasive infections in vaccinated persons and classical diphtheria in unvaccinated persons. In the presented study we analysed genetic changes in C. diphtheriae isolates collected in Poland from the period before the introduction of the mass anti-diphtheria vaccination to the present time when over 98% of the population is vaccinated. A total of 62 C. diphtheriae isolates collected in the 1950s–1960s, 1990s and 2000–2016 in Poland were investigated. Examined properties of the isolates included toxigenic status, presence of tox gene, biotype, MLST type (ST) and type of infection. A total of 12 sequence types (STs) were identified among the analysed C. diphtheriae isolates. The highest variability of STs was observed among isolates from diphtheria and asymptomatic carriers collected in the XX century. Over 95% of isolates collected from invasive and wound infections in 2004–2016 belonged to ST8. Isolates from the XX century represented all four biotypes: mitis, gravis, intermedius and belfanti, but the belfanti biotype appeared only after the epidemic in the 1990s. All except three isolates from the XXI century represented the biotype gravis. During a diphtheria epidemic period, non-epidemic clones of C. diphtheriae might also disseminate and persist in a particular area after the epidemic. An increase of the anti-diphtheria antibody level in the population causes not only the elimination of toxigenic Strains from the population but may also influence the reduction of diversity of C. diphtheriae isolates. MLST types do not reflect the virulence of isolates. Each ST can be represented by various virulent variants representing various pathogenic capacities, for example toxigenic non-invasive, Nontoxigenic invasive and Nontoxigenic non-invasive.
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Changes in MLST profiles and biotypes of Corynebacterium diphtheriae isolates from the diphtheria outbreak period to the period of invasive infections caused by Nontoxigenic Strains in Poland (1950–2016)
BMC Infectious Diseases, 2018Co-Authors: Urszula Czajka, Aldona Wiatrzyk, Ewa Mosiej, Kamila Formińska, Aleksandra A ZasadaAbstract:Background Corynebacterium diphtheriae is a re-emerging pathogen in Europe causing invasive infections in vaccinated persons and classical diphtheria in unvaccinated persons. In the presented study we analysed genetic changes in C. diphtheriae isolates collected in Poland from the period before the introduction of the mass anti-diphtheria vaccination to the present time when over 98% of the population is vaccinated. Methods A total of 62 C. diphtheriae isolates collected in the 1950s–1960s, 1990s and 2000–2016 in Poland were investigated. Examined properties of the isolates included toxigenic status, presence of tox gene, biotype, MLST type (ST) and type of infection. Results A total of 12 sequence types (STs) were identified among the analysed C. diphtheriae isolates. The highest variability of STs was observed among isolates from diphtheria and asymptomatic carriers collected in the XX century. Over 95% of isolates collected from invasive and wound infections in 2004–2016 belonged to ST8. Isolates from the XX century represented all four biotypes: mitis, gravis, intermedius and belfanti , but the belfanti biotype appeared only after the epidemic in the 1990s. All except three isolates from the XXI century represented the biotype gravis . Conclusions During a diphtheria epidemic period, non-epidemic clones of C. diphtheriae might also disseminate and persist in a particular area after the epidemic. An increase of the anti-diphtheria antibody level in the population causes not only the elimination of toxigenic Strains from the population but may also influence the reduction of diversity of C. diphtheriae isolates. MLST types do not reflect the virulence of isolates. Each ST can be represented by various virulent variants representing various pathogenic capacities, for example toxigenic non-invasive, Nontoxigenic invasive and Nontoxigenic non-invasive.
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Multilocus Sequence Typing Identifies Evidence for Recombination and Two Distinct Lineages of Corynebacterium diphtheriae
Journal of Clinical Microbiology, 2010Co-Authors: F. Bolt, Pamela K. Cassiday, Maria Lucia Tondella, Aruni Dezoysa, Androulla Efstratiou, Andreas Sing, Aleksandra A Zasada, Kathryn Bernard, Nicole Guiso, Edgar BadellAbstract:We describe the development of a multilocus sequence typing (MLST) scheme for Corynebacterium diphtheriae, the causative agent of the potentially fatal upper respiratory disease diphtheria. Global changes in diphtheria epidemiology are highlighted by the recent epidemic in the former Soviet Union (FSU) and also by the emergence of Nontoxigenic Strains causing atypical disease. Although numerous techniques have been developed to characterize C. diphtheriae, their use is hindered by limited portability and, in some instances, poor reproducibility. One hundred fifty isolates from 18 countries and encompassing a period of 50 years were analyzed by multilocus sequence typing (MLST). Strain discrimination was in accordance with previous ribotyping data, and clonal complexes associated with disease outbreaks were clearly identified by MLST. The data produced are portable, reproducible, and unambiguous. The MLST scheme described provides a valuable tool for monitoring and characterizing endemic and epidemic C. diphtheriae Strains. Furthermore, multilocus sequence analysis of the nucleotide data reveals two distinct lineages within the population of C. diphtheriae examined, one of which is composed exclusively of biotype belfanti isolates and the other of multiple biotypes.
Tanja Popovic - One of the best experts on this subject based on the ideXlab platform.
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development of a direct pcr assay for detection of the diphtheria toxin gene
Journal of Clinical Microbiology, 1997Co-Authors: Hiroshi Nakao, Tanja PopovicAbstract:PCR has proved to be a reliable tool for the detection of the diphtheria toxin gene, tox, and its use has allowed for the rapid differentiation between toxigenic and Nontoxigenic Strains. In this study, this PCR was further developed, evaluated, and standardized to detect this gene directly from clinical specimens. Optimal conditions for collection, transport, and storage of the clinical specimens and isolation and purification of DNA from the clinical specimens were defined. With two sets of primers that detect the A and B subunits of the diphtheria toxin gene, sensitivity levels of 50 and 500 CFU/PCR mixture, respectively, were achieved. This PCR was evaluated with 162 clinical samples collected from patients with diphtheria and other upper respiratory tract infections, as well as from healthy individuals.
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application of pcr for detection of toxigenic corynebacterium diphtheriae Strains isolated during the russian diphtheria epidemic 1990 through 1994
Journal of Clinical Microbiology, 1995Co-Authors: V M Mikhailovich, V G Melnikov, I K Mazurova, I K Wachsmuth, Jay D Wenger, Melinda Wharton, Hiroshi Nakao, Tanja PopovicAbstract:A total of 250 Corynebacterium diphtheriae isolates from clinical cases and carriers in Russia were assayed by PCR directed at the A subunit of the diphtheria toxin gene to distinguish toxigenic from Nontoxigenic Strains; 170 Strains were positive as indicated by the presence of the 248-bp amplicon. The results of this PCR assay were in complete concordance with those of the standard immunoprecipitation assay (Elek), and the PCR assay is a useful tool for rapid identification in clinical laboratories.
Urszula Czajka - One of the best experts on this subject based on the ideXlab platform.
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Changes in MLST profiles and biotypes of Corynebacterium diphtheriae isolates from the diphtheria outbreak period to the period of invasive infections caused by Nontoxigenic Strains in Poland (1950–2016)
BMC Infectious Diseases, 2018Co-Authors: Urszula Czajka, Aldona Wiatrzyk, Ewa Mosiej, Kamila Formińska, Aleksandra A ZasadaAbstract:Background Corynebacterium diphtheriae is a re-emerging pathogen in Europe causing invasive infections in vaccinated persons and classical diphtheria in unvaccinated persons. In the presented study we analysed genetic changes in C. diphtheriae isolates collected in Poland from the period before the introduction of the mass anti-diphtheria vaccination to the present time when over 98% of the population is vaccinated. Methods A total of 62 C. diphtheriae isolates collected in the 1950s–1960s, 1990s and 2000–2016 in Poland were investigated. Examined properties of the isolates included toxigenic status, presence of tox gene, biotype, MLST type (ST) and type of infection. Results A total of 12 sequence types (STs) were identified among the analysed C. diphtheriae isolates. The highest variability of STs was observed among isolates from diphtheria and asymptomatic carriers collected in the XX century. Over 95% of isolates collected from invasive and wound infections in 2004–2016 belonged to ST8. Isolates from the XX century represented all four biotypes: mitis, gravis, intermedius and belfanti , but the belfanti biotype appeared only after the epidemic in the 1990s. All except three isolates from the XXI century represented the biotype gravis . Conclusions During a diphtheria epidemic period, non-epidemic clones of C. diphtheriae might also disseminate and persist in a particular area after the epidemic. An increase of the anti-diphtheria antibody level in the population causes not only the elimination of toxigenic Strains from the population but may also influence the reduction of diversity of C. diphtheriae isolates. MLST types do not reflect the virulence of isolates. Each ST can be represented by various virulent variants representing various pathogenic capacities, for example toxigenic non-invasive, Nontoxigenic invasive and Nontoxigenic non-invasive.
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changes in mlst profiles and biotypes of corynebacterium diphtheriae isolates from the diphtheria outbreak period to the period of invasive infections caused by Nontoxigenic Strains in poland 1950 2016
BMC Infectious Diseases, 2018Co-Authors: Urszula Czajka, Aldona Wiatrzyk, Ewa Mosiej, Kamila Formińska, Aleksandra A ZasadaAbstract:Corynebacterium diphtheriae is a re-emerging pathogen in Europe causing invasive infections in vaccinated persons and classical diphtheria in unvaccinated persons. In the presented study we analysed genetic changes in C. diphtheriae isolates collected in Poland from the period before the introduction of the mass anti-diphtheria vaccination to the present time when over 98% of the population is vaccinated. A total of 62 C. diphtheriae isolates collected in the 1950s–1960s, 1990s and 2000–2016 in Poland were investigated. Examined properties of the isolates included toxigenic status, presence of tox gene, biotype, MLST type (ST) and type of infection. A total of 12 sequence types (STs) were identified among the analysed C. diphtheriae isolates. The highest variability of STs was observed among isolates from diphtheria and asymptomatic carriers collected in the XX century. Over 95% of isolates collected from invasive and wound infections in 2004–2016 belonged to ST8. Isolates from the XX century represented all four biotypes: mitis, gravis, intermedius and belfanti, but the belfanti biotype appeared only after the epidemic in the 1990s. All except three isolates from the XXI century represented the biotype gravis. During a diphtheria epidemic period, non-epidemic clones of C. diphtheriae might also disseminate and persist in a particular area after the epidemic. An increase of the anti-diphtheria antibody level in the population causes not only the elimination of toxigenic Strains from the population but may also influence the reduction of diversity of C. diphtheriae isolates. MLST types do not reflect the virulence of isolates. Each ST can be represented by various virulent variants representing various pathogenic capacities, for example toxigenic non-invasive, Nontoxigenic invasive and Nontoxigenic non-invasive.
Biao Kan - One of the best experts on this subject based on the ideXlab platform.
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proteins involved in difference of sorbitol fermentation rates of the toxigenic and Nontoxigenic vibrio cholerae el tor Strains revealed by comparative proteome analysis
BMC Microbiology, 2009Co-Authors: Ruibai Wang, Shouyi Gao, Hongzhi Zhang, Haiyan Qiu, Biao KanAbstract:The Nontoxigenic V. cholerae El Tor Strains ferment sorbitol faster than the toxigenic Strains, hence fast-fermenting and slow-fermenting Strains are defined by sorbitol fermentation test. This test has been used for more than 40 years in cholera surveillance and strain analysis in China. Understanding of the mechanisms of sorbitol metabolism of the toxigenic and Nontoxigenic Strains may help to explore the genome and metabolism divergence in these Strains. Here we used comparative proteomic analysis to find the proteins which may be involved in such metabolic difference. We found the production of formate and lactic acid in the sorbitol fermentation medium of the Nontoxigenic strain was earlier than of the toxigenic strain. We compared the protein expression profiles of the toxigenic strain N16961 and Nontoxigenic strain JS32 cultured in sorbitol fermentation medium, by using fructose fermentation medium as the control. Seventy-three differential protein spots were found and further identified by MALDI-MS. The difference of product of fructose-specific IIA/FPR component gene and mannitol-1-P dehydrogenase, may be involved in the difference of sorbitol transportation and dehydrogenation in the sorbitol fast- and slow-fermenting Strains. The difference of the relative transcription levels of pyruvate formate-lyase to pyruvate dehydrogenase between the toxigenic and Nontoxigenic Strains may be also responsible for the time and ability difference of formate production between these Strains. Multiple factors involved in different metabolism steps may affect the sorbitol fermentation in the toxigenic and Nontoxigenic Strains of V. cholerae El Tor.
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gene expression differences of toxigenic and Nontoxigenic vibrio cholerae Strains in mannitol fermentation medium and luria bertani broth
Acta Microbiologica Sinica, 2009Co-Authors: Hongzhi Zhang, Bo Pang, Li Zhang, Biao KanAbstract:OBJECTIVE To analyze gene expression differences of toxigenic and Nontoxigenic Strains of El Tor Vibrio cholerae growing separately in mannitol fermentation medium and LB (Luria-Bertani) broth. METHODS Total RNA was extracted from the mannitol slow-fermenting strain N16961 (toxigenic) and the mannitol fast-fermenting strain 93097 (Nontoxigenic) at 1 h of fermentation. The large scale gene expression profiles were detected and compared with high throughout microarray. RESULTS By comparing the Strains growing in different cultures, we found 142 differentially expressed genes in N16961 and 418 genes in 93097. Most of these genes were grouped into six functional classes. They were mainly related to transport and binding, energy metabolism, protein biosynthesis, and protein fate. CONCLUSION The expression levels of genes in N16961 and 93097 were affected by culture conditions, which can serve as basis for further studying the mechanism of metabolism of mannitol.
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genetic diversity of toxigenic and Nontoxigenic vibrio cholerae serogroups o1 and o139 revealed by array based comparative genomic hybridization
Journal of Bacteriology, 2007Co-Authors: Bo Pang, Meiying Yan, Zhigang Cui, Baowei Diao, Yonghong Ren, Shouyi Gao, Liang Zhang, Biao KanAbstract:Toxigenic serogroups O1 and O139 of Vibrio cholerae may cause cholera epidemics or pandemics. Nontoxigenic Strains within these serogroups also exist in the environment, and also some may cause sporadic cases of disease. Herein, we investigate the genomic diversity among toxigenic and Nontoxigenic O1 and O139 Strains by comparative genomic microarray hybridization with the genome of El Tor strain N16961 as a base. Conservation of the toxigenic O1 El Tor and O139 Strains is found as previously reported, whereas accumulation of genome changes was documented in toxigenic El Tor Strains isolated within the 40 years of the seventh pandemic. High phylogenetic diversity in Nontoxigenic O1 and O139 Strains is observed, and most of the genes absent from Nontoxigenic Strains are clustered together in the N16961 genome. By comparing these toxigenic and Nontoxigenic Strains, we observed that the small chromosome of V. cholerae is quite conservative and stable, outside of the superintegron region. In contrast to the general stability of the genome, the superintegron demonstrates pronounced divergence among toxigenic and Nontoxigenic Strains. Additionally, sequence variation in virulence-related genes is found in Nontoxigenic El Tor Strains, and we speculate that these intermediate Strains may have pathogenic potential should they acquire CTX prophage alleles and other gene clusters. This genome-wide comparison of toxigenic and Nontoxigenic V. cholerae Strains may promote understanding of clonal differentiation of V. cholerae and contribute to an understanding of the origins and clonal selection of epidemic Strains.
Jesus Murillo - One of the best experts on this subject based on the ideXlab platform.
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short communication detection by multiplex pcr and characterization of Nontoxigenic Strains of pseudomonas syringae pv phaseolicola from different places in spain
Spanish Journal of Agricultural Research, 2006Co-Authors: Arantza Rico, M Erdozain, Amaia Ortizbarredo, J Ruiz I De Galarreta, Jesus MurilloAbstract:The efficient control of halo blight, caused by Pseudomonas syringae pv. phaseolicola, is primarily based on the use of pathogen-free seed. Detection of the pathogen in seeds is currently carried out with high-sensitive methods based on the detection by PCR of genes involved in the biosynthesis of phaseolotoxin, which was believed to be produced by all Strains of the pathogen with epidemiological importance. However, field epidemics of halo blight in the county of Castilla y Leon, Spain, are often associated to Nontoxigenic isolates of P. syringae pv. phaseolicola, which cannot be detected using current molecular and serological methods. The results presented in this work show the existence of Nontoxigenic isolates of P. syringae pv. phaseolicola in areas other than Castilla y Leon, indicating the need to establish a reliable methodology for seed certification. A simple two-step methodology is presented with the aim to identify both types of isolates that is based on a multiplex enrichment PCR of seed soakates and on pathogenicity assays.
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Nontoxigenic Strains of pseudomonas syringae pv phaseolicola are a main cause of halo blight of beans in spain and escape current detection methods
Phytopathology, 2003Co-Authors: Arantza Rico, R Lopez, Carmen Asensio, Teresa M Aizpun, Carmen Asensios M Manzanera, Jesus MurilloAbstract:Rico, A., Lopez, R., Asensio, C., Aizpun, M. T., Asensio-S.-Manzanera, M. C., and Murillo, J. 2003. Nontoxigenic Strains of Pseudomonas syringae pv. phaseolicola are a main cause of halo blight of beans in Spain and escape current detection methods. Phytopathology 93:15531559. From a collection of 152 pseudomonads isolated from diseased beans in Spain, 138 (91%) of the Strains were identified as Pseudomonas syringae pv. phaseolicola and the rest as P. syringae pv. syringae. The P. syringae pv. phaseolicola Strains produced typical water-soaked lesions on bean pods, although 95 of them did not produce phaseolotoxin in vitro. Ninety-four of these isolates did not produce the expected 0.5-kb product after polymerase chain reaction (PCR) amplification using primers specific for open reading frame (ORF) 6 of the phaseolotoxin (tox) gene cluster and did not contain DNA homologous to ORF 6 in Southern hybridization experiments. To our knowledge, this is the first report of the widespread occurrence in the field of Strains of P. syringae pv. phaseolicola lacking the tox cluster, which contrasts sharply with the general belief that Tox + isolates are the only ones with epidemiological importance. Additionally, the tox– isolates were not specifically detected by a commercial polyclonal antisera in an enzyme-linked immunosorbent assay. Accordingly, it is possible that the certification of seed lots as free of the pathogen cannot be reliably done in Spain, or in any other country where tox– Strains might occur frequently, using current PCR or serological protocols. The amplification of three avirulence genes by PCR allowed us to make predictions of the P. syringae pv. phaseolicola race structure, as confirmed by plant assays. Six races (races 1, 2, 5, 6, 7, and 9) were identified, with race 7 being the most prevalent (46.1%) followed by races 6 (21.3%) and 1 (9.0%). All the tox– isolates contained gene avrPphF, typical of races 1, 5, 7, and 9. The three major bacterial diseases of common bean (Phaseolus vulgaris L.) are caused by pathovars of Pseudomonas syringae and Xanthomonas campestris and result in economically important losses worldwide (31,41). In particular, P. syringae pv. phaseolicola, causing halo blight, is probably the most important bacterial pathogen of bean in Europe, the United States, and many other countries. Spain is not an exception. Some of these pathogens cause field epidemics (1,4,41). P. syringae pv. phaseolicola was first described in Spain in 1939 and it also appears to be the main cause of bacterioses of bean, although P. syringae pv. syringae was reported to be of local importance in certain areas and bean cultivars (4,7). Although it is still considered a quarantine organism in Spain, X. campestris pv. phaseoli has been repeatedly isolated in the field (1,4; C. Asensio, unpublished data) and works are in progress to determine its importance for bean production. Control of halo blight is difficult, and the only practical methods for its management are the use of pathogen-free seed and appropriate cultural practices and planting of resistant cultivars. The presence of extremely low levels of primary inoculum can initiate severe epidemics under favorable conditions, and in consequence, certification of seed as free of the pathogen requires the use of highly sensitive and specific methods. Detection and identification of P. syringae pv. phaseolicola has been done using different methods that include microbiological assays (15), nucleic acid hybridization (36), and different serological methods (44,51), for which there are a number of commercially available antibodies. However, due to its effectiveness and low cost, several researchers have developed detection assays based on the amplification of specific DNA sequences by means of polymerase chain
