RÉSUMÉ
Objective:To study the clustered regularly interspaced short palindromic repeats (CRISPR) genotype of Yersinia pestis and its regional distribution characteristics in natural plague focus of Tibet Autonomous Region. Methods:A total of 125 representative Yersinia pestis strains isolated from natural plague focus in Tibet Autonomous Region at different times, regions, hosts and vectors were selected as experimental strains, and the phenol chloroform mixed extraction method was used to extract Yersinia pestis DNA. Three pairs of CRISPR primers (for YPa, YPb, YPc locus) were used to amplify the DNA of the experimental strains, and the CRISPR genotype of Yersinia pestis was determined by sequencing. Results:All 125 strains of Yersinia pestis had three CRISPR locus: YPa, YPb, and YPc. A total of 18 spacer were found, including 8 in YPa loci, 6 in YPb loci, and 4 in YPc loci. Two new types of spacers had been discovered, namely b52 and c14. CRISPR typing revealed 10 genotypes, including G1, G7, G7-b4''', G7-b52, G7-c2 -, G8, G22, G22-a4 -, G22-b4''', and G22-c14, of which 6 were newly discovered genotypes. Among the 125 experimental strains, G7 was the main genotype, accounting for 65.6% (82/125), which was distributed in 6 prefecture level citys and 1 region of Tibet Autonomous Region. Next were G22 and G7-c2 - genetypes, accounting for 14.4% (18/125) and 11.2% (14/125), respectively. G22 gene type was distributed in Nagqu, Changdu, Lhasa citys, and Ngari Prefecture, while G7-c2 - genetype was distributed in Shigatse and Shannan cities. Conclusion:The CRISPR locus of Yersinia pestis in natural plague focus of Tibet Autonomous Region is highly polymorphic, and the Yersinia pestis strains with different genotypes have obvious regional distribution characteristics.
RÉSUMÉ
To characterize human antibodies against low-calcium response V(LcrV)antigen of Yersinia pestis,the mono-clonal antibodies were screened and assayed.Antibody gene was derived from peripheral blood mononuclear cells of the vaccin-ees immunized by plague subunit vaccine in phase Ⅱb clinical trial.Human ScFv antibody library was constructed by phage dis-play.After panning library by using recombinant LcrV antigen,antibody variable genes were sequenced and converted into IgG1 format to evaluate its binding specificity and relevant parameters.An anti-plague human ScFv antibody library was estab-lished contained 7.54× 108 independent clones.After panning by LcrV antigen,3 human antibodies named as RV-B4,RV-D1 and RV-E8,respectively,were identified.Using indirect enzyme-linked immunosorbent assay(ELISA)and Western blot(WB),the specific bindings of the mAbs to LcrV antigen were confirmed.The dissociation constant(KD)of them to LcrV is 2.1 nmol/L,1.24 nmol/L and 42 nmol/L,respectively.Minor protective efficacy was found among 3 human antibodies in Y.pestis 141-infected mice.Three anti-LcrV monoclonal antibodies generated from immunized vaccinees were binding specific antibod-ies and could not block plague infection in mice.These antibodies are the potential candidate reagents for basic research of plague immunity and the application of plague diagnosis.
RÉSUMÉ
The growth of three plague phages from Qinghai Plateau in two Yersinia pestis strains(plague vaccine strains EV76 and 614F)and four non-Yersinia pestis strains(Yersinia pseudotuberculosis PTB3,PTB5,Escherichia coli V517,and Yersinia enterocolitica 52302-2)were detected through a micromethod based on the OmniLogTM microbial identification system and by the drop method,to provide a scientific basis for future ecological studies and classification based on the host range.For plague vaccine strains EV76 and 614F,successful phage infection and subsequent phage growth were observed in the host bacte-rium.Diminished bacterial growth and respiration and a concomitant decrease in color were observed with the OmniLogTM mi-crobial identification system at 33 ℃ for 48 h.Yersinia pseudotuberculosis PTB5 was sensitive to Yersinia pestis phage 476,but Yersinia pseudotuberculosis PST5 was insensitive to phage 087 and 072204.Three strains of non-Yersinia pestis(Yersinia pseudotuberculosis PTB3,Escherichia coli V517,and Yersinia enterocolitica 52302-2)were insensitive to Yersinia pestis pha-ges 087,072204,and 476 showed similar growth curves.The growth of phages 476 and 087,as determined with the drop method,in two Yersinia pestis strains(plague vaccine strains EV76 and 614F)and four non-Yersinia pestis strains(Yersinia pseudotuberculosis PTB3,Escherichia coli V517,and Yersin-ia enterocolitica 52302-2)showed the same results at 37 ℃,on the basis of comparisons with the OmniLogTM microbial i-dentification system;in contrast,phages 072204 did not show plaques on solid medium at 37 ℃ with plague vaccine strains EV76 and 614F.Determination based on the OmniLogTM detection system can be used as an alternative to the traditional determination of the host range,thus providing favorable application val-ue for determining the interaction between the phage and host bacteria.
RÉSUMÉ
@#Abstract: Objective To understand the epidemic characteristics of plague and the phenotypic characteristics of Yersinia pestis strains strains in Dulan County, Qinghai Province, so as to provide theoretical reference for timely adjustment of the local plague surveillance program and prevention of plague recurrence, as well as effective experimental basis for clinical treatment and prevention. Methods The biochemical characteristics, virulence factor identification and plasmid analysis of 23 Yersinia pestis strains isolated from Dulan County, Qinghai Province from 1964 to 1994 were studied by conventional methods and molecular biology techniques. At the same time, the different region (DFR) method was applied to study the genetic typing of 23 Yersinia pestis strains isolated from Dulan County, Qinghai Province according to 23 different regions of plague genome and the designed primers based on PMT1. Results Among the 23 Y. pestis strains isolated from Dulan County, 22 strains of Y. pestis were palaeotypic biotypes, and biochemical types were Qinghai-Tibet Plateau type, and 1 strain was incompatible with both biotypes and biochemical types in this area. And 86.96% (20/23) of Y. pestis strains had four virulence factors (F1+, Pst I+, VW+, Pgm+). All of the tested strains produced F1 and Pst I, while 95.65% (22/23) of tested strains were positive for VW, and 86.96% were Pgm positive. All the 23 strains carried three plasmids, with a relative molecular weight (Mr) of 6×106, 45×106, 52×106, and these plasmids formed a stable plasmid spectrum: 6×106, 45×106, 52 ×106. The DFR typing results showed that Yersinia pestis could be divided into two genotypes, namely G05 and G08. Nineteen Yersinia pestis strains were G08 and four strains were G05. Conclusions The 23 strains of Yersinia pestis isolated from Dulan County were mostly of Qinghai-Tibet Plateau type, and had stable biochemical characteristics. The virulence of Yersinia pestis was strong. The results of plasmid analysis and genotyping showed that the Yersinia pestis had the etiological characteristics of Qinghai-Tibet Plateau, which was consistent with the characteristics of Marmota himalayana plague foci in Qinghai-Tibet Plateau.
RÉSUMÉ
@#Abstract: Objective To investigate the current status of streptomycin resistance of Yersinia pestis caused by point mutations of rpsL gene in Qinghai, so as to provide theoretical basis for precise clinical medication and prevention of drug resistance of human plague outbreak in South area of Qinghai Province in the future. Methods A total of 104 representative strains of Yersinia pestis collected from plague patients, vector insects and intermediate hosts in South area of Qinghai Province from 1957 to 2009 were screened, isolated and cultured by Hiss agar plates. The DNA of representative Yersinia pestis was extracted by sodium dodecyl sulfate lysis and phenol-chloroform method. The primers forward primer and reverse primer and TaqMan-MGB probes probe1 [FAM] and probe2 [VIC] were designed for the rpsL gene of streptomycin resistance gene in China. Real-time PCR with TaqMan-MGB fluorescent probe was used to detect the mutations of rpsL gene in streptomycin resistance locus of 104 strains of Yersinia pestis in South area of Qinghai Province. Results The FAM test results of 104 strains in South area of Qinghai Province were positive, corresponding to the detection of rpsL (128 : A ), RFU peak >1 000,negative <200. VIC test results of all tested strains were negative, corresponding to the detection of rpsL (128:G), RFU peak <200, positive >1 000. That is, no strains with rpsL gene mutation related to streptomycin resistance were found in the 104 strains of Yersinia pestis in Qingnan Province. Conclusion This study provides basic data on the distribution of streptomycin resistance of Yersinia pestis in South area of Qinghai Province, and lays a foundation for preventing the occurrence of drug resistance and clinical treatment of Yersinia pestis in South area of Qinghai Province.
RÉSUMÉ
Objective:To learn about the clustered regularly interspaced short palindromic repeats (CRISPR) genotyping of Yersinia pestis in Yushu Tibetan Autonomous Prefecture (Yushu for short), Qinghai Province, and to explore its genetic characteristics. Methods:In this study, 44 representative strains isolated from local natural plague focus in Yushu from 1963 to 2007 were selected as experimental objects to extract DNA. Primers targeting the three CRISPR loci (YPa, YPb, and YPc) were designed for PCR amplification. The amplified products were sequenced and analyzed to identify the CRISPR spacer, and to determine the CRISPR genotypes and clusters.Results:Twenty-three spacers including 14 of YPa, 6 of YPb and 3 of YPc were observed among 44 strains, of which 2 spacers (a106 and a107) were firstly identified. According to the spacer arrays, the strains were divided into 15 CRISPR genotypes and classified into 6 CRISPR clusters which were Cb4, Cc3', Ca7, Ca7', CaΔ5' and Ca35', respectively. Among them, Ca7 was the most epidemic dominant cluster (34 strains) in Yushu.Conclusion:The CRISPR loci of Yersinia pestis in Yushu have multiple genotypes, high genetic polymorphism, and complex population structure.
RÉSUMÉ
Objective:To study the phenotype and genotype distribution of Yersinia pestis ( Y. pestis) in different natural foci of plague in China, so as to provide scientific basis for plague prevention and control. Methods:A total of 2 184 strains of Y. pestis isolated from different time periods, regions, hosts and vectors in 11 plague natural foci of China since 1943 were selected for biochemical type identification, glycolysis test, virulence factor test [capsule antigen (F1), pesticin Ⅰ (Pst Ⅰ), virulence antigen factor (VWa), pigmentation factor (Pgm)], different region (DFR) typing and clustered regularly interspaced short palindromic repeats (CRISPR) typing. Results:There were 16 biochemical types of Y. pestis in the natural foci of plague in China, and each biochemical type showed obvious regional distribution in each foci. Most strains were positive for ass hide glue glycolysis (89.79%, 1 961/2 184), maltose (80.13%, 1 750/2 184), glycerol (94.23%, 2 058/2 184), and denitrification (82.78%, 1 808/2 184), and negative for rhamnose (88.78%, 1 939/2 184) and melibiose (85.62%, 1 870/2 184). Virulence factor test results showed that 99.95% (2 183/2 184) of Y. pestis were F1 positive; 99.73% (2 178/2 184) of Y. pestis can produce Pst Ⅰ; 73.31% (1 601/2 184) of Y. pestis were VWa positive and 26.69% (583/2 184) were VWa negative; Pgm positive strains accounted for 72.62% (1 586/2 184), Pgm negative strains accounted for 21.52% (470/2 184), and Pgm mixed type strains accounted for 5.86% (128/2 184). According to DFR typing results, there were 52 genotypes in 2 184 strains of Y. pestis, of which 19 were major genotypes and 33 were minor genotypes. CRISPR typing revealed 16 major genotypes, of which 7 were newly discovered. Conclusion:The phenotypes and genotypes of Y. pestis in various natural foci of plague in China are diverse and have geographical distribution characteristics.
RÉSUMÉ
@#Abstract: Objective To understand the phenotypic and genetic characteristics of Yersinia pestis strains isolated from Himalayan marmot natural focus area and domestic rat plague focus area in southern China, and provide reference for mastering the pathogenic characteristics of Yersinia pestis of two plague foci. Methods A total of 412 of Yersinia pestis strains isolated from Himalayan marmot plague focus and domestic rat plague focus of southern China were subjected to to sorbitol fermentation assays, virulence factor, different region (DFR) typing, and clustered regularly interspaced palindromic repeats (CRISPR) typing. Results The biochemical types of Y. pestis from the two plague foci showed distinct regional distribution features. Five biochemical phenotypes were identified in Yersinia pestis isolated from Himalayan marmot natural focus area, while only one biochemical phenotype was identified in strains isolated from the domestic rat plague focus of Southern China. Most of the Yersinia pestis isolated from the two plague foci were capable of producing the virulence factors of Fl and PstI. Among the strains from Himalayan marmot focus, 70.53% (201/285) were VW-positive, 75.09% (214/285) were Pgm-positive, 20.00% (57/285) of the strains were Pgm-negative, and 5.26% (15/285) were Pgm mixed-type strains. Among strains from domestic rat plague focus of southern China, 37.80% (48/127) were VW-positive, 29.13% (37/127) were Pgm-positive, 58.27% (74/127) were Pgm-negative, and 12.60% (16/127) were Pgm mixed-type strains. DFR typing revealed 22 genotypes of Y. pestis from the Himalayan marmot plague focus, with the main genotypes being type 5, 7, 8, 10, 19, 32 and 49. All strains from domestic rat plague focus area in southern China belonged to type 9. CRISPR typing revealed that all strains from the Himalayan marmot natural focus were classified into 7 CRISPR gene clusters and 14 CRISPR genotypes, with the main genotypes being G7, G22, G26-a1'and G22-A1'. All strains from domestic rat plague focus area in southern China belonged to CRISPR genotype G30, with the gene cluster being Ca8. Conclusions The phenotypes and genotypes of the Yersinia pestis of Himalayan marmot plague focus are diverse, with an obvious characteristics of geographical distribution. The phenotype and genotype of the Yersinia pestis of domestic rat plague focus of Southern China are single. DFR and CRISPR genotyping methods with phenotypic characteristics can effectively identify the Yersinia pestis isolated from the two plague foci, thereby meeting the needs of identification and traceability research.
RÉSUMÉ
Objective:To investigate the changes in adaptive phenotypes of Yersinia pestis ( Yp) during successive passages in macrophages. Methods:A Yp strain of 201-MI was induced by 50 successive passages of Yp 201 strain in Raw264.7 cells. Phenotypic characteristics of 201 and 201-MI strains were compared by analyzing their survival rates in macrophages, growth curves, biofilm formation abilities, acid and hydrogen peroxide-stress tolerance, and virulence to mammal cells (Raw264.7 and HeLa cells) and mice. Results:Comparing with 201 strain, 201-MI strain showed various phenotypic changes, including higher survival rate in Raw264.7 cells, faster growth in iron-deficient medium, higher tolerance to acid and hydrogen peroxide, decreased biofilm formation ability, and less damages to Raw264.7 and HeLa cells. More-over, 201-MI strain showed decreased virulence to mice in both subcutaneous and intraperitoneal challenges. Preliminary comparative genomics analysis revealed some indel and nonsense mutations in 201-MI strain, which might account for its phenotype changes.Conclusions:After successive passages in macrophages, Yp showed some phenotypic changes, which might reflect its adaptive evolution under the pressure of macrophages. Detailed multi-omics analysis would be of great help to understand the underlying genetic mechanisms of these changes, and the related Yp-macrophage interaction processes as well.
RÉSUMÉ
@#Abstract: Objective To detect and analyze the antiserum of Yersinia pestis phage in Marmota himalayana blood from the natural plague foci of Qinghai-Tibet Plateau by micro-bolus technique, to provide a theoretical basis for interaction between phages and mammalian immunology, phage therapy and interaction between bacteriophage and ecology in future. Methods Using diagnostic Yersinia pestis phage and 3 wild plague phages from Qinghai-Tibet Plateau Natural Plague Foci as antigens, 847 serums of Marmota Himalayana blood, from Tongde, Guinan, Gonghe, Xinghai, Tianjun foci counties in Qinghai Plateau, were collected from July to September in 2020, 2021 and determined on antiserum of Yersinia pestis phage by microplate method and double agar plate method. Results The neutralization reaction experiment lasted for 24 hours between 4 phage and 847 serums by microplate method independently. These mixtures were tested by double agar plate method. All results were negative on antiserum of Yersinia pestis bacteriophage. Conclusions The positive antiserum of Yersinia pestis phage in Marmota himalayana were not found the natural plague foci of Qinghai-Tibet Plateau, which agreed with plague epidemiology in 5 foci counties in Qinghai plateau from 2020-2021, that was a characteristic of the resting period. In other words, it was in the absence of plague pathogen. It also showed indirectly that the absence or weak presence of Yersinia pestis bacteriophage in the plague foci. It showed a lower frequency on host animals coming into contact with phages naturally. The antiserum of Yersinia pestis phage may be related to the form of plague infection and the intensity of the disease.
RÉSUMÉ
Objective:To investigate the genotypes of clustered regularly interspaced short palindromic repeats (CRISPR) of Yersinia pestis ( Y. pestis) and it's regional distribution in the plague natural foci of Qinghai-Tibet Plateau. Methods:In this study, 1 004 strains of Y. pestis isolated from different hosts and vectors in different regions from 1954 to 2011 were selected as experimental objects, which preserved in Qinghai Institute for Endemic Disease Prevention and Control, and DNA of Y. pestis was extracted by traditional phenol-chloroform method. Three CRISPR loci (YPa, YPb and YPc) were amplified by PCR and sequenced, respectively, and the CRISPR sequences were compared with the CRISPRDictionary database recently reported in the literature to identify CRISPR spacer. For the spacer discovered for the first time at each CRISPR locus, Blast sequence alignment was performed in the National Center for Biotechnology Information (NCBI) database to speculate the source of gene sequence. Genotyping of Y. pestis from Qinghai-Tibet Plateau was performed based on the polymorphism of CRISPR spacer array. Results:A total of 53 spacers were found in 1 004 strains of Y. pestis, of which 6 spacers were newly discovered, namely a105, a106, a107, b51, b52 and c14. The 1 004 strains of Y. pestis were divided into 10 groups with 44 different CRISPR genotypes, and 15 new genotypes were found. The dominant genotypes of Y. pestis were G26-a1', G7, G22, G24-a1', G22-a1', G9 and G26-a1'a60 in Himalayan Marmot plague natural foci, and G37-a6' in Qinghai Microtinae plague natural foci. Conclusion:The CRISPR genotypes of Y. pestis in the plague natural foci of Qinghai-Tibet Plateau are high diverse and have significant regional distribution characteristics.
RÉSUMÉ
Objective:To study the genotyping and regional distribution characteristics of Yersinia pestis by single nucleotide polymorphism (SNP) in Gansu Province. Methods:A total of 52 strains of Yersinia pestis isolated from Himalaya Marmot plague foci and Spermophilus alaschanicus plague foci in Gansu Province from 1962 to 2017 were selected for culture and extraction of DNA. The genomic DNA of Yersinia pestis was sequenced by the second generation of Illumina PE150 to identify the SNP sites. The species characteristics of Yersinia pestis in Gansu Province was determined by the Kimura-2-parameter model of neighbor joining of Mega 10.0 software based on the SNP sites. The molecular evolutionary tree of the groups was determined by Hasegawa-Kishino-Yano model of maximum likelihood method according to the SNP sites. Results:A total of 103 SNP sites were identified in 52 strains of Yersinia pestis in Gansu Province, including 28 intergenic loci, 43 non-synonymous mutations, 31 synonymous mutations and 1 nonsense mutation. The 52 strains of Yersinia pestis were divided into 2 biotypes and 3 groups, which were ancient type (1.IN2, 3.ANT) and medieval type (2.MED). Among them, 35 strains belonged to 1.IN2 group, 13 strains belonged to 3.ANT group, and 4 strains belonged to 2.MED group. The 1.IN2 group was further divided into 5 subgroups: the groups of Yuerhong Town and Dangchengwan Town in Subei County, the groups of Mati Town and Dahe Town in Sunan County, and the group of Xiahe County. The 3.ANT group was further divided into 2 subgroups: the groups of Hongliuwan Town in Aksay County and Machang in Dangchengwan Town of Subei County. Conclusion:The SNP method can be used to genotype Yersinia pestis from different plague foci in Gansu Province, which has certain regional characteristics.
RÉSUMÉ
Objective:To analyze the pathogenic characteristics of Yersinia pestis in a plague natural foci in Qinghai-Tibet Plateau. Methods:In this study, 1 378 strains of Yersinia pestis isolated from different regions, hosts and vectors in Qinghai-Tibet Plateau from 1954 to 2016 were taken as the research objects. Phenotypic characteristics, plasmid spectrum and genotype of the strains were studied by using conventional techniques and molecular biological techniques. The etiology and geographical distribution of the plague were studied. Results:There were 6 biochemical types of Yersinia pestis in Qinghai-Tibet Plateau, namely Qinghai-Tibet Plateau, Qilian Mountain, Gangdis Mountain, Kunlun Mountain A, Kunlun Mountain B and Chuanqing Plateau. This study found that the Qinghai-Tibet Plateau type strain was not only distributed in north Tibet Plateau, but also distributed in south Tibet, and the distribution of Gangdis Mountain type strain extended to south Tibet. Four virulence factors (capsule antigen, yersinin, virulence antigen and pigmentation factor) were found in 79.97% (1 102/1 378) Yersinia pestis. The results also showed that there were 12 kinds of plasmids carried by Yersinia pestis strains in Qinghai-Tibet Plateau, which constituted 17 kinds of plasmid spectrum. There were 3 kinds of the largest plasmids with taxonomic properties, forming their respective relatively independent distribution areas. The study of different regions (DFR) type showed that 5, 8, 14, 19, 32 and 44 of 1 378 strains were the main genotypes, and the main genome types had obvious geographical distribution. Conclusions:All the tested strains have the characteristics of plague pathogen in Qinghai-Tibet Plateau. The polymorphism of the main hosts, vectors and the ecological landscape of plague geography in the plague foci in Qinghai-Tibet Plateau may lead to the diversity of biochemical characters, plasmid spectrum and geno types of Yersinia pestis.
RÉSUMÉ
Objective:To explore the biochemical characteristics, virulence factors and other phenotypes of the strains of Yersinia pestis isolated in Jianchuan County Yunnan Province in 2017, and to analyze the nature and source of the new plague epidemic. Methods:Three strains of Yersinia pestis (JC109 rat, JC109 fleas and JC113) isolated from Daqing Village, Jinhua Town, Jianchuan County, Dali Prefecture, Yunnan Province in 2017, and 2 associated strains of Yersinia pestis (LJ01 in Yulong County, Lijiang City and LJ04 in Gucheng District of Lijiang City), 5 control strains ( Yersinia pestis JC1332, LJ485, BN2636, EV-76 and Yersinia pseudotuberculosis PST-1), preserved by the Central Laboratory of Yunnan Institute for Endemic Disease Control and Prevention were collected. The biochemical characteristics and ecotypes of Yersinia pestis were analyzed by using arabinose, rhamnose, denbiose, maltose and glycerol fermentation experiments and nitrate reduction experiments. Combining pigmentation factor (pgm), virulence antigen (VW) detection and nutritional requirements test results to determine the virulence of Yersinia pestis. Results:The Yersinia pestis JC109 rat, JC109 fleas and JC113 all fermented arabinose, maltose and glycerol, but didn't ferment rhamnose and denbiose; and the nitrate reduction test was positive. The ecological type belonged to the Himalayan Marmot plague strain of Qinghai-Tibet plateau. The virulence factors pgm and VW tests were positive, the nutritional requirement type was phenylalanine dependent and glutamate independent. It had the same phenotype as the LJ01 strain, but different from the JC1332 strain. Conclusions:The newly isolated strains in Jianchuan County are the same as those in the Lijiang Yulong wild rodent plague foci. This outbreak may have been imported from the Lijiang Yulong wild rodent plague foci to the south.
RÉSUMÉ
Objective:To observe the efficacy of levofloxacin and moxifloxacin in the treatment of experimental plague in guinea pigs.Methods:A total of 70 SPF guinea pigs, female, weighing 250 to 300 g, were selected and randomly divided into 7 groups according to body weight by random number table. There were 10 guinea pigs in each group: levofloxacin 24, 48, 72 h groups, moxifloxacin 24, 48, 72 h groups (drug treatment was carried out after being infected with Yersinia pestis for 24, 48 and 72 h, respectively) and control group (without treatment). Experimentally infected plague model was established through guinea pigs subcutaneous injection of 141 strains of Yersinia pestis [1 × 10 7 colony forming unit (CFU)]; referring to the adult dose in the "National Pharmacopoeia of the People's Republic of China", the daily dose of guinea pigs was converted by Shi Xinyou's animal conversion coefficient method for treatment, the doses of levofloxacin and moxifloxacin in each guinea pig were 12.0 and 9.6 mg/d, respectively for 9 days. The guinea pigs were killed 9 days after drug withdrawal for bacteriological examination and pathological observation, and the cure rate was calculated. Results:The cure rates of levofloxacin 24, 48 and 72 h groups were 100.0% (10/10), 70.0% (7/10) and 6/6, respectively. The cure rates of moxifloxacin 24, 48 and 72 h groups were 100.0% (10/10), 100.0% (10/10) and 5/7, respectively, and the cure rate of animals in the control group was 0 (0/10). Compared with the control group, there were significant differences in the efficacy of moxifloxacin 24, 48 and 72 h groups and levofloxacin 24, 48 and 72 h groups ( P < 0.05). There was no significant difference between the two drugs at the same starting time ( P > 0.05). Conclusion:The effects of levofloxacin and moxifloxacin on animal plague infection are ideal and the two drugs can be used as a substitute for streptomycin in plague treatment under special circumstances.
RÉSUMÉ
Objective@#To investigate reciprocal regulation between Fur and two RyhB homologs in @*Methods@#Regulatory relationships were assessed by a combination of colony morphology assay, primer extension, electrophoretic mobility shift assay and DNase I footprinting.@*Results@#Fur bound to the promoter-proximal DNA regions of @*Conclusion@#Fur and the two RyhB homologs exert negative reciprocal regulation, and RyhB homologs have a positive regulatory effect on biofilm formation in
Sujet(s)
Protéines bactériennes/métabolisme , Biofilms , Régulation de l'expression des gènes bactériens/physiologie , Yersinia pestis/physiologieRÉSUMÉ
Objetivo: caracterizar aspectos epidemiológicos e clínicos fundamentais, discutir a metodologia do diagnóstico e tecer recomendações sobre as condutas perante a suspeição de casos de peste. Métodos: revisão bibliográfica e levantamento das internações e mortes por peste registradas no Sistema de Informações Hospitalares do Sistema Único de Saúde. Resultados e conclusões: a existência de diagnósticos equivocados de uma doença potencialmente fatal, além dos registros hipotéticos de internações e mortes, constitui um desafio a ser superado, pois espelha uma situação inaceitável, em que um possível e insólito diagnóstico não é investigado e acumula-se nos sistemas de informação.
Objective: to characterize ground epidemiological and clinical aspects of, discuss the methodology of diagnosis and draw recommendations about the management of suspect cases of plague. Methods: literature review and data collection of hospitalizations and deaths due to plague recorded in the Hospital Information System of the Unified Health System. Results and conclusions: the existence of mistaken diagnoses of a potentially fatal disease, as well as hypothetical records of hospitalization and deaths, is a challenge to be overcome, because it reflects an unacceptable panorama in which a possible and unusual diagnosis is not investigated and accumulates in the information systems.
Sujet(s)
Yersinia pestis , ÉpidémiologieRÉSUMÉ
RESUMEN La peste es una enfermedad reemergente causada por Yersinia pestis. Los humanos generalmente adquieren la enfermedad por picaduras de pulgas. La peste es una enfermedad sistémica fulminante, siendo la peste neumónica la forma más letal. El diagnóstico tardío es una de las principales causas de mortalidad y diseminación de la enfermedad, dado que limita la efectividad de las medidas de control. Presentamos el caso de un varón de 42 años, que previamente había viajado a una zona endémica de peste, y luego presentó hiperpirexia, hipotensión, y adenopatía inguinal inflamatoria. A pesar del cuadro clínico muy característico, nadie (antes del ingreso a nuestro hospital) sospechó peste. Se inició una combinación antibiótica efectiva y tratamiento intensivo recién al quinto día de enfermedad. El paciente evolucionó con shock séptico, falla respiratoria, y muerte. Se confirmó peste por reacción en cadena de polimerasa (PCR). Este caso enfatiza la importancia de tener un alto índice de sospecha para peste.
ABSTRACT Plague is a re-emerging disease caused by the bacteria Yersinia pestis. Humans usually get the disease through the bite of an infected flea. Plague is a fulminant systemic disease, with pneumonic plague being the most lethal form. Late diagnosis is one of the main causes of mortality and spread of the disease, as it limits the effectiveness of control measures. We present the case of a 42-year-old male, who had previously traveled to an endemic plague area and then presented hyperpyrexia, hypotension, and inflammatory inguinal adenopathy. Despite the very characteristic clinical picture, nobody (before admission to our hospital) suspected plague. An effective combination of antibiotics and intensive treatment was initiated only on the fifth day of illness. The patient went into septic shock, respiratory failure, and death. Plague was confirmed by polymerase chain reaction (PCR). This case emphasizes the importance of having a high suspicion rate for plague.
Sujet(s)
Adulte , Humains , Mâle , Peste/diagnostic , Issue fatale , Retard de diagnosticRÉSUMÉ
Objective@#To investigate whether plague phages were present in the indicator animals of plague foci in Yunnan Province, and to explore their epidemiological significance.@*Methods@#Anus swabs were collected from indicator animals (dogs or cats) of the 41 plague affected villages in 26 towns of 10 cities (counties, districts) of Yunnan plague foci from November of 2015 to March of 2018. The Yersinia pestis phages were isolated by plague vaccine strain EV76. The isolation of plague phages from different plague foci, the isolation of plague phages from different canine species (cats), the polymorphism of plaque and the host spectrum of phages were analyzed.@*Results@#A total of 1 014 indicator animals (1 003 dogs and 11 cats) were studied, and 102 of plague phages were isolated. In the 10 cities (counties, districts), plague phages were only not isolated from Lancang County, and the plague phages were isolated from the other 9 cities (counties, districts). The separation rates from high to low were as follows: Yiliang County (21.00%, 21/100), Menghai County (19.23%, 25/130), Yuanjiang County (11.63%, 10/86), Midu County (11.50%, 13/113), Wenshan County (10.10%, 10/99), Mile Country (7.07%, 7/99), Lianghe County (6.67%, 7/105), Baoshan Longyang District (4.90%, 5/102) and Gengma County (3.81%, 4/105). Of the 102 plague phages, 75 were isolated from the native dogs (Chinese pastoral dogs, 9.32%, 75/805), 20 from the pug dogs (13.70%, 20/146), 5 from the wolf dogs (17.24%, 5/29), 1 from Samoye (1/4) and 1 from Alaska dog (1/2). The plaque of the phage was divided by five appearance of complete lysis (the plate was clear), large (2.5-4.0 mm), big (1.5-< 2.5 mm), middle (0.5-< 1.5 mm) and small (< 0.5 mm). The representative phages were all of the Myoviridae family. Most of the phages could lysis the strains of Yersinia pestis, and some phages could lysis Shigella and type 5 Yersinia pseudotuberculosis (PST5).@*Conclusion@#The plague phages are present in the plague foci of Yunnan, and the phages are polymorphic.
RÉSUMÉ
Objective@#To investigate the correlation of meteorological factors with the numbers of marmots and parasitic fleas in the plague foci of Himalayan marmot in Subei County and Sunan County of Gansu Province.@*Methods@#The surveillance data(from Gansu Provincial Center for Disease Control and Prevention) of natural plague foci of Subei, Sunan of Himalayan marmot from 1982 to 2016 and the meteorological factors data (from China Meteorological Data Sharing Service Network) such as annual average temperature, rainfall and relative humidity during the same period were collected. The correlation between marmot density, body flea index and meteorological factors were analyzed by SAS 9.3 software. Based on the meteorological data as an independent variable in current year and previous 1, 2, and 3 years (relative to previous 1, 2, and 3 years as the reference), the marmot density as the dependent variable, the time series semiparametric generalized additive model (GAM) was established to quantitatively study the nonlinear effect of meteorological factors on the marmot density by R2.3.2 software.@*Results@#From 1982 to 2016, the marmot density in Subei County of Gansu Province was 0.29-6.63 per hectare, and the body flea index range was 0.04-4.56; the marmot density in Sunan County of Gansu Province was 1.22-7.92 per hectare, and the body flea index range was 0.06-0.42. In Subei County, the marmot density was correlated with the previous 1 year rainfall and relative humidity, respectively (r= 0.43, 0.36, P < 0.05), and negatively correlated with the average temperature of the year and the previous 1, 3 years (r=-0.58,-0.55,-0.41, P < 0.05). In Sunan County, the marmot density was correlated with the relative humidity of the year and the previous 1 year rainfall and relative humidity, respectively (r= 0.36, 0.57, 0.43, P < 0.05). In Subei County, the body flea index was negatively correlated with the average temperature of the year and the previous 1, 2, 3 years, respectively(r=-0.57,-0.43,-0.31,-0.37, P < 0.05). In Sunan County, there was a negative correlation between the body flea index and the average temperature of the year and the previous 1, 2, 3 years (r=-0.71,-0.46,-0.38,-0.40, P < 0.05). After controlling other influencing factors, the results of the GAM showed that for every 1 mm increase in rainfall of the year in Subei County, the marmot density increased 0.93%; for every 1% increase in relative humidity of the previous 3 year in Subei County, the marmot density increased 25.34%; for every 1 mm increase in rainfall of the previous 3 year in Sunan County, the marmot density increased 1.69%.@*Conclusions@#The numbers of marmots in the plague foci of Himalayan marmot in Subei County and Sunan County of Gansu Province are closely related to rainfall and relative humidity, and the influence has different hysteresis effects. Surface temperature is a important factor affecting the population of parasitic fleas.