Comparative study of drug susceptibility testing and whole genome test testing anti-tuberculosis drug resistance / 国际检验医学杂志

Objective To compare the categorical agreement between drug susceptibility testing(DST)and whole genome sequencing(WGS)for the detection of drug resistance in Mycobacterium tuberculosis(MTB),and to explore the characteristics of WGS for MTB drug resistance detection.Methods A total of 71 MTB clinical isolates retained in West China Hospital of Sichuan University from 2018 to 2020 were included in this study.The MTB strains were tested for resistance to 14 anti-tuberculosis drugs,including Isoniazid(INH),Rifampicin(RIF),Rifabutin(RFB),Ethambutol(EMB),Streptomycin(SM),Moxifloxacin(MFX),Ofloxacin(OFX),Levofloxacin(LFX),Amikacin(AMK),Kanamycin(KAN),Capreomycin(CPM),Para-aminosalicylic acid(PAS),Ethionamide(ETH)and Clofazimine(CLO),using both DST(colorimetric redox indicator meth-od)and WGS methods.Kappa test was performed to analyze the results of drug resistance detection for both methods.Results Based on DST and WGS methods to detect anti-tuberculosis drug resistance in seventy-one MTB clinical isolates,the results showed that the agreement rate of RIF,RFB,SM,MFX,OFX and LFX ex-ceeded 90.00％,and the kappa values were all greater than 0.80,with near perfect agreement;The agreement rates of INH and EMB were 84.51％and 81.69％,and Kappa values were 0.68 and 0.54,respectively,with fair agreement.No more than two drug resistant MTB strains of AMK and KAN were detected by both meth-ods,and the resistance rate was less than 3.00％.The agreement rates of CPM,ETH,PAS,and CLO ranged from 61.97％to 91.55％,and the Kappa values were less than 0.40,with slight or fair agreement.Conclusion There are differences in the ability of WGS to detect resistance to various anti-tuberculosis drugs,and it is more effective in detecting resistance to six anti-tuberculosis drugs,including RIF,RFB,SM,MFX,OFX and LFX,while there are still certain differences in detecting resistance to other anti-tuberculosis drugs compared with DST.It is necessary to further clarify the detailed resistance mechanisms of relevant anti-tu-berculosis drugs and to explore the standardization of WGS for drug resistance detection.

Genome-wide analysis of a Coxsackievirus A8 isolate in Yunnan Province / 中国生物制品学杂志

@#Objective To analyze the whole genome sequence and genetic characteristics of the Yunnan isolate of Coxsackievirus A8(CVA8),A8-1/YN/CHN/2019,in order to understand the prevalence and variation of CVA8.Methods The primers for CVA8 were designed,the viral RNA was extracted,the VP1 sequence was amplified by RT-PCR and sequenced,and the whole genome was spliced using BioEdit 7.2.3. MEGA 7.0 software was used for the phylogenetic analysis,and Simplot 3.5.1 and RDP4 software were used for the recombination analysis.Results Strain A8-1/YN/CHN/2019 was7 396 nt long and encoded 2 188 amino acids. The homologies of nucleotide and amino acid sequences between VP1 and CVA8 prototype strain AF081299/Donovan/USA/1998 were 81. 04% and 95. 24%,respectively. Strain A8-1/YN/CHN/2019 belonged to genotype E,while the other Chinese isolates were located in genotypes D and E. Recombination analysis revealed that strain A8-1/YN/CHN/2019 recombined on segments P2 and P3 of the non-structural coding region.Conclusion Strain A8-1/YN/CHN/2019 is of genotype E and has recombination events in the non-structural regions of the P2 and P3 segments.

Study on the toxicity characteristics of a clinical bloodstream isolate of Salmonella Telelkebir / 中国人兽共患病学报

The ICR(Institute of Cancer Research)mouse infection model was constructed to study the pathogenicity of Sal-monella Telelkebir serotype,and the pathogenic identification of mouse isolates was carried out.Observe the bacterial excretion cycle,evaluate the pathogenicity of Salmonella serotype to mice,and calculate the LD50 by the changes in clinical characteris-tics,histopathology and tissue bacterial load of infected mice;by flight mass spectrometry,biochemical identification,serotype identification,molecular typing and other experiments,compared with human isolates;virulence gene analysis was carried out by PCR experiment and whole genome sequencing.The LD50 of Salmonella Telelkebir is 2.67 × 108 CFU/mL;curling and fluffing may occur 0.5 h after infection;autopsy of dead mice showed that the small intestine was severely congested,with more bubbles and fluid accumulation,cecal necrosis,liver apical degeneration and necrosis,necrotic foci on the surface of the kidney and spleen atrophy;the bacterial load of spleen,kidney,lung,liver and jejunum in mice reached its peak at 3 days after infection,while that of heart at 6 days;the bacterial excretion time of the high-dose group exceeded 100 days;The level of CD3 in tissues increased with increasing dose,with inflammatory cell infiltration,myocardial capillary dilation and hyperemia,large area of vacuoles,degeneration and necrosis of hepatocytes,obvious enlargement of splenic sinus,blurred zoning,thickening of glomerular basement membrane,partial exfoliation of ciliated epithelium,atrophy and exfoliation of jejunal villi;PCR and whole genome sequencing revealed Salmonella-related virulence genes such as cdtB,plt A and pltB.This study was the first to successfully establish the ICR mouse model of Salmonella Telelkebir,demonstrating that this serotype of Salmonella has some pathogenicity.

Virulence determinants and genetic diversity of foodborne Yersinia enterocolitica isolated from Wenzhou / 中国人兽共患病学报

The aim of this study was to investigate the virulence determinants and genetic diversity of foodborne Yersinia enterocolitica from Wenzhou.A total of 71 strains of Yersinia enterocolitica were isolated from food and foodborne diarrhea ca-ses in Wenzhou,and their biotypes,serotypes,and drug resistance were analyzed.On the basis of whole genome sequencing,we assessed virulence gene profiles,and performed multilocus sequence typing(MLST)and core gene multilocus sequence typ-ing(cgMLST).A total of 94.4％(67/71)of isolates belonged to biotype 1A,and the highest proportion had serotype lA/O∶5(29.6％,21/71).The sensitivity rates of the isolates to 14 antibiotics exceeded 95.8％.A total of 16 categories and 126 viru-lence genes were identified,with two strains carrying the pYV plasmid and chromosome-related virulence genes.ST3(31.6％,12/38)was the most widespread MLST type,and cgMLST analysis revealed no dense clusters of genotypes except for strains sharing the same ST.In conclusion,pathogenic strains were identified from foodborne Yersinia enterocolitica in Wenzhou and were found to exhibit high genetic polymorphism.Enhanced regulatory supervision is essential to prevent the outbreak of food-borne diseases caused by Yersinia enterocolitica.

First molecular characterization of Escherichia coli O157:H7 isolates from clinical samples in Paraguay using whole-genome sequencing Molecular characterization of Escherichia coli O157 isolates from Paraguay / Primera caracterización molecular de aislamientos de Escherichia coli O157:H7 provenientes de muestras clínicas en Paraguay utilizando secuenciación de genoma completo

Abstract Escherichia coli O157:H7 is a foodborne pathogen implicated in numerous outbreaks worldwide that has the ability to cause extra-intestinal complications in humans. The Enteropathogens Division of the Central Public Health Laboratory (CPHL) in Paraguay is working to improve the genomic characterization of Shiga toxin-producing E. coli (STEC) to enhance laboratory-based surveillance and investigation of foodborne disease outbreaks. Whole genome sequencing (WGS) is proposed worldwide to be used in the routine laboratory as a high-resolution tool that allows to have all the results in a single workflow. This study aimed to carry out for the first time, the genomic characterization by WGS of nine STEC O157:H7 strains isolated from human samples in Paraguay. We were able to identify virulence and resistance mechanisms, MLST subtype, and even establish the phylogenetic relationships between isolates. Furthermore, we detected the presence of strains belonging to hypervirulent clade 8 in most of the isolates studied.

Resumen Escherichia coli O157:H7 es un patógeno transmitido por alimentos implicado en numerosos brotes en todo el mundo y es capaz de causar complicaciones extraintestinales en humanos. La sección de «Enteropatógenos¼ del Laboratorio Central de Salud Pública trabaja en mejorar la caracterización genómica de STEC, de modo de potenciar la vigilancia laboratorial y la investigación de brotes de enfermedades transmitidas por alimentos. La secuenciación de genoma completo (WGS, por sus siglas en inglés) se propone a nivel mundial como una herramienta de alta resolución para ser utilizada en el laboratorio de rutina, ya que permite obtener todos los resultados en un único proceso. El objetivo de este trabajo fue llevar a cabo, por primera vez, la caracterización genómica por WGS de nueve cepas STEC O157:H7 aisladas en Paraguay a partir de muestras de origen humano. Pudimos identificar los factores de virulencia, los mecanismos de resistencia, el subtipo MLST, e incluso pudimos establecer la relación filogenética entre los aislamientos. Además, detectamos que la mayoría de las cepas pertenecían al clado hipervirulento 8.

Advancements in Genetic Diversity and Genome Characteristics of Durians (Durio spp.)

Durian is one of the important fruit crops in Southeast Asia with its unique flavor and important economic benefits. Breeding programs have produced hundreds of different cultivars of durian. These cultivars are classified mainly by fruit and flower characteristics, which cannot be observed at the vegetative stage. Therefore, molecular biology is a powerful tool to approach and explore the genetic characteristics of durians. Many studies based on barcoded DNA and molecular markers have been conducted and valuable data have been exploited. Thanks to the advancement of sequencing technology, the plastid genome and the whole genome were sequenced in some durian cultivars. The data revealed reliable data on the structure and function of several genes. This review aims to update recent studies on the durian genome attributes and potential applications in the conservation of germplasm, authentication, and exploration of the gene structure and function of this specialty plant.

Genome sequencing and analysis of BCG strain for vaccine production in China / 上海预防医学

ObjectiveTo conduct the sequencing and preliminarily analysis of the whole genome of BCG Shanghai D2PB302 strain （hereinafter referred to as BCG Shanghai D2 strain）， which has been used exclusively for the vaccine production in China. MethodsThe DNA of of BCG Shanghai D2 strain （D2-JIA12-1） was extracted， and the whole genome was sequenced by Pacbio-RS Ⅱ. The sequence data was assembled by Smrtlink and polished with the illumina data. Genes， tRNA and rRNA were predicted based on the sequence data. The functional annotation of predicted genes was performed through BLASTP. The IVE-TB antigen gene and MTBVAC were selected as the target sequences to be compared with Mycobacterium tuberculosis H37Rv （NC_000962.3）. ResultsThe sequence length of BCG Shanghai D2 strain was 4 045 232 bp， and the GC content was 65.66%. A total of 4 259 protein-encoding genes were predicted， with an average gene size of 933 bp. 2 476 genes had biological functions and others were hypothetical proteins.144 virulence genes were obtained by comparing with the VFDB. There were 29 type Ⅶ secretion system genes and 10 PE/PPE protein family genes. ConclusionThe whole genome sequence of BCG Shanghai D2 strain is clarified. It lays a broad foundation for subsequent detection of the stability of major antigen genes.

Genotyping Characteristics of Human Fecal Escherichia coli and Their Association with Multidrug Resistance in Miyun District, Beijing / 生物医学与环境科学（英文）

OBJECTIVE@#To explore the genotyping characteristics of human fecal Escherichia coli( E. coli) and the relationships between antibiotic resistance genes (ARGs) and multidrug resistance (MDR) of E. coli in Miyun District, Beijing, an area with high incidence of infectious diarrheal cases but no related data.@*METHODS@#Over a period of 3 years, 94 E. coli strains were isolated from fecal samples collected from Miyun District Hospital, a surveillance hospital of the National Pathogen Identification Network. The antibiotic susceptibility of the isolates was determined by the broth microdilution method. ARGs, multilocus sequence typing (MLST), and polymorphism trees were analyzed using whole-genome sequencing data (WGS).@*RESULTS@#This study revealed that 68.09% of the isolates had MDR, prevalent and distributed in different clades, with a relatively high rate and low pathogenicity. There was no difference in MDR between the diarrheal (49/70) and healthy groups (15/24).@*CONCLUSION@#We developed a random forest (RF) prediction model of TEM.1 + baeR + mphA + mphB + QnrS1 + AAC.3-IId to identify MDR status, highlighting its potential for early resistance identification. The causes of MDR are likely mobile units transmitting the ARGs. In the future, we will continue to strengthen the monitoring of ARGs and MDR, and increase the number of strains to further verify the accuracy of the MDR markers.

Multiomics and Multidimensional Testing for Efficacy Monitoring of Patients with Lymphoma / 中国实验血液学杂志

OBJECTIVE@#To explore the role of a new blood-based, multiomics and multidimensional method for evaluating the efficacy of patients with lymphoma.@*METHODS@#10 ml peripheral blood was extracted from each patient, and the genomic copy number aberrations (CNA) and fragment size (FS) were evaluated by low-depth whole genome sequencing of cfDNA, and the level of a group of plasma tumor marker (PTM) were detected at the same time. The cancer efficacy score (CES) was obtained by standardized transformation of the value of above three numerical indexes, and the changes of CES before and after treatment were compared to evaluate the patient's response to the treatment regimen.@*RESULTS@#A total of 35 patients' baseline data were collected, of which 23 cases (65.7%) had elevated CES values. 18 patients underwent the first time test. The results showed that the CES value of 9 patients with positive baseline CES decreased significantly at the first test, and the efficacy evaluation was PR, which was highly consistent with the imaging evaluation results of the same period. At the same time, the CNA variation spectrum of all patients were evaluated and it was found that 23 patients had partial amplification or deletion of chromosome fragments. The most common amplification site was 8q24.21, which contains important oncogenes such as MYC. The most common deletion sites were 1p36.32, 4q21.23, 6q21, 6q27, 14q32.33, and tumor suppressor-related genes such as PRDM1, ATG5, AIM1, FOXO3 and HACE1 were expressed in the above regions, so these deletions may be related to the occurrence and development of lymphoma.@*CONCLUSION@#With the advantages of more convenience, sensitivity and non-invasive, this multiomics and multidimensional efficacy detection method can evaluate the tumor load of patients with lymphoma at the molecular level, and make more accurate efficacy evaluation, which is expected to serve the clinic better.

Clinical practice of whole-genome sequencing in the rapid diagnosis of critically ill neonates / 中国当代儿科杂志

OBJECTIVES@#To explore the application of whole-genome sequencing (WGS) in the rapid clinical diagnosis of critically ill neonates.@*METHODS@#The critically ill neonates who admitted to the neonatal intensive care unit of Children's Hospital of Fudan University and underwent WGS from August to September, 2019 were enrolled in this prospective study. The genetic testing results and clinical outcome were analyzed with reference to the sequencing data and clinical features of the neonates.@*RESULTS@#A total of 15 neonates were tested, among whom there were 9 boys and 6 girls. The main reason for hospitalization included abnormal breathing in 7 neonates, poor response in 2 neonates, feeding difficulty in 2 neonates, fever in 1 neonate, hypothermia in 1 neonate, preterm birth in 1 neonate, and convulsion in 1 neonate. The mean turn-around time was 4.5 days for WGS. Finally a genetic diagnosis was obtained for 3 neonates, with a positive diagnostic rate of 20% (3/15). Among the 3 neonates, 2 neonates were withdrawn from the treatment due to severe conditions and 1 neonate died on the day when the sample was sent for genetic testing, whose etiology could be explained by the results of genetic testing.@*CONCLUSIONS@#WGS technique can provide a timely and effective diagnosis for critically ill neonates suspected of genetic diseases and provide genetic evidence for clinical treatment of critically ill cases.

X-linked neurological dysplasia caused by a new mutation of the PAK3 gene in a newborn / 中华实用儿科临床杂志

The clinical features, examination findings and genetic testing results of a newborn with neurobehavioral developmental abnormality caused by the PAK3 gene mutation in the Department of Neonatology, Anhui Provincial Children′s Hospital were retrospectively analyzed in November 11, 2021.The male 9-day-old newborn presented with the difficult-to-wean for 9 days after birth.The child had repeated startle reflexes, decreased muscle tension in the extremities, and partial primitive reflexes.Amplitude-integrated electroencephalogram (aEEG) showed the lower and upper boundary voltage of 10 μV and 40 μV, respectively.Obvious mature sleep-wake cycles were not found, and 2 electric seizures were recorded.The aEEG suggested the moderate-to-severe abnormal aEEG.Magnetic resonance imaging showed that the corpus callosum was slightly thinner.The family-centered diagnostic exosome sequencing showed a missense mutation of the PAK3 gene[c.1327 (exon18) G>A, p.G443R], which has not been previously reported at home and abroad.This case enriched the clinical phenotype of the PAK3 gene mutation and suggested the potential value of whole genome sequencing in clinical diagnosis and genetic guidance.

Molecular features and drug-resistance genes of 70 erythromycin-resistant group B Streptococcus strains in Zhengzhou / 中华微生物学和免疫学杂志

Objective:To investigate the phenotypes, molecular types and drug-resistance genes of erythromycin (ERY)-resistant group B Streptococcus (GBS) in pregnant women in late pregnancy in Zhengzhou and provide basic data for the prevention, control and treatment of GBS infection. Methods:This study retrospectively collected 86 GBS strains isolated from the vaginal secretions of pregnant women in late pregnancy at Maternal and Child Health Hospital of Henan Province from 2021 to 2022. ERY-resistant GBS strains were selected using the ERY disk diffusion method, and their susceptibility to 10 different antibiotics was tested. Whole-genome sequencing was performed to analyze their molecular features including molecular types, clonal complex groups and drug-resistance genes. Drug-resistance genes carried by GBS strains belonging to different clonal complex groups were compared.Results:There were 70 ERY-resistant GBS strains. Among them, 7.14%(5/70) exhibited an inducible resistance phenotype to macrolide-lincosamide-streptogramin B (MLSB) antibiotics; 84.29%(59/70) showed constitutive resistance to MLSB antibiotics; 8.57%(6/70) were resistant to macrolides but susceptible to lincosamides. The resistance rates of these strains to clindamycin (CLI), tetracycline (TE) and levofloxacin (LEV) were 91.43%(64/70), 54.29%(38/70) and 60.00%(42/70), respectively. These ERY-resistant strains exhibited multidrug resistance patterns with 40.00%(28/70) showing ERY-CLI-LEV resistance phenotype and 30.00%(21/70) showing ERY-CLI-TE resistance phenotype. The major drug-resistance genes carried by the 70 GBS strains were macrolide/lincosamide resistance genes mreA (100.00%) and ermB (53/70, 75.71%), aminoglycoside resistance genes ant (6)-Ⅰ a (22/70, 31.43%) and aph(3′)-Ⅲ (18/70, 25.71%), and tetracycline resistance genes tetM (22/70, 31.43%) and tetO (13/70, 18.57%). These strains belonged to 12 sequence types derived from seven clonal complexes (CCs) and 48.57%(34/70) of them were clustered into CC12. All CC12 strains harbored ermB, but none carried ermA. The positive rates of lsaE, lunB, and aac (6′)- aph(2" ) in CC19 and CC651 strains, ant (6)-Ⅰ a in CC651 and CC452 strains, and mefA and msrD in CC19 and CC23 strains were significantly higher than those in CC12 strains ( P<0.001). Conclusions:ERY-resistant GBS in Zhengzhou exhibited diverse drug resistance phenotypes and molecular types. CC12 was the most prevalent clonal complex in this region. The constitutive MLSB resistance phenotype and ermB gene were the most common ERY resistance phenotype and genotype, respectively, and tetM gene was related to tetracycline resistance. Furthermore, the drug-resistance genes varied in GBS strains of different clonal complexes. This study suggested that close attention should be paid to the epidemiological situation of GBS in this region and the effectiveness of antibiotics used for clinical prevention and treatment of GBS infection should be carefully evaluated.

Characteristics of whole genome analysis of severe acute respiratory syndrome coronavirus 2 during different epidemic periods in Wuxi City / 中华传染病杂志

Objective:To understand the genome sequence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and spike protein variations during different epidemic periods in Wuxi City.Methods:Nucleic acid was extracted from the nasopharyngeal swab samples of six local cases of coronavirus disease 2019 (COVID-19) (from January to February, 2020) and 13 imported cases of COVID-19 (from March to September, 2021) in Wuxi City, and the whole genome was amplified to construct the sequencing library. The second-generation sequencer was used for sequencing. The CLC Genomics Workbench (21 version) software was used to analyze the offline data with NC_045512.2 as the reference strain, and MEGA 7.0 software was used to construct the phylogenetic tree.Identification of type was conducted by Nextstrain typing method and phylogenetic assignment of named global outbreak lineages (Pangolin) typing method.Results:There were five subtypes in Nextstrain and seven subtypes in Pangolin of the nineteen patients with COVID-19. Compared with NC_045512.2, the median nucleotide mutation sites were 29 (range 0 to 42) and amino acid mutation sites were 20 (range 0 to 34). The six local and 13 imported cases had no common nucleotide mutation sites and were in different evolutionary branches. The sequences of the six local cases were highly homologous with the reference strain sequences (NC_045512.2) at the early stage of the pandemic, and the evolutionary distance was close to that of the reference strain. The 13 imported cases were obviously divided into three evolutionary branches (Alpha, Beta, Delta variant).The four Beta variants shared eight amino acid mutation sites in spike protein, and the two Alpha variants shared eight amino acid mutation sites in spike protein, and the seven Delta variants shared five amino acid mutation sites in spike protein.Conclusions:New mutations of SARS-CoV-2 are constantly emerging during the epidemic. The increase of the nucleotide sites number may result in the change of spike protein amino acid. Therefore, the whole-genome sequencing analysis plays an important role in the accurate tracing of epidemic origin and adjustment of prevention and control measures.

Prenatal imaging classification and potential diseases of fetal abnormal sylvian fissure / 中华超声影像学杂志

Objective:To assess the ultrasonographic features and potential diseases of fetal abnormal sylvian fissure(SF), and to explore the value of whole-genome sequencing (WGS) in prenatal detection.Methods:A total of 28 fetuses with a sonographic diagnosis of abnormal SF in Shenzhen Maternal and Child Health Hospital Affiliated to Southern Medical University between October 2018 and October 2020 were prospectively included. The fetal brain was evaluated by neuroultrasound and intrauterine MRI in detail. Amniotic fluid/cord blood obtained by amniocentesis or tissue samples from umbilical cord after birth were collected for WGS. Pregnancy outcomes and postnatal MRI were recorded, and neurodevelopment of live-born infants was followed up for more than 24 months after delivery.Results:During the study period, 28 fetuses with abnormal SF were identified, with a gestational age of 21.3-30.0 (24.8±2.0) weeks. Abnormal SF presented in MCD ( n=15, 53.6%), chromosomal anomalies ( n=3, 10.7%) or single-gene genetic syndromes ( n=3, 10.7%) with the affected fetuses showing developmental delay, hydrocephalus or leukomalacia ( n=4, 14.2%), corpus callosal agenesis with large interhemispheric cysts ( n=1, 3.6%), benign subarachnoid space enlargement with arachnoid cysts ( n=1, 3.6%), and multiple malformations ( n=1, 3.6%). Among the 15 cases with MCD, the most common pathology was lissencephaly/pachygyria, followed by schizencephaly, severe microcephaly, hemimegalencephaly with paraventricular heterotopia, and polymicrogyria. Abnormal SF presented bilaterally in 23 fetuses and unilaterally in 5. All cases were categorized into six types depending on SF morphology in the transthalamic section: no plateau-like or a small insula, linear type, irregular corrugated SF, Z-shaped, and cyst occupying type. In addition to abnormal SF, associated anomalies or mild variations were identified in all fetuses. There were 17 cases underwent intrauterine MRI, and 13 cases underwent postnatal MRI examination.And 25 pregnancies were terminated; 3 were born alive, and 2 had typical syndromic changes with poor neurodevelopmental prognosis. A related pathogenic genetic variant was detected in 57.1% (16/28) fetus, and the incidence of single nucleotide variants(SNVs) was 42.9% (12/28), among which de novo SNVs accounted for 91.7% (11/12). Conclusions:Fetal abnormal SF could be classified based on the ultrasonographic features of transthalamic section. Fetal abnormal SF may indicate MCD, some chromosomal abnormalities or single-gene genetic syndromes that may lead to poor neurodevelopmental outcomes, and may be affected by extra-cortical factors. It is suggested to carry out targeted prenatal genetic diagnosis for fetuses with abnormal SF.

Antimicrobial resistance and genomic characteristics of Salmonella enterica serovar Derby isolates from clinical patients and food sources in Hangzhou / 中华微生物学和免疫学杂志

Objective:To analyze the antimicrobial resistance and genomic characteristics of Salmonella enterica serovar Derby strains isolated from human and food sources in Hangzhou. Methods:A total of 60 Salmonella enterica serovar Derby strains isolated in Hangzhou during the period from 2015 to 2020 were subjected to antimicrobial susceptibility testing, pulsed field gel electrophoresis (PFGE) typing and whole-genome sequencing. Multilocus sequence typing (MLST), core genome multilocus sequence typing (cgMLST) and the identification of antimicrobial resistance genes were performed using the sequencing data. Phylogenetic tree based on the single nucleotide polymorphism (SNP) sites in the 60 genomes from Hangzhou and 379 genomes from public databases was constructed. Results:No significant difference was observed in the drug resistance rates between the clinical strains and food strains in Hangzhou. The multidrug resistance (MDR) rate was 76.7% (46/60). All of the 60 Salmonella Derby strains were positive for the antimicrobial resistance genes aac(6′)- Iaa and fosA7. The 60 strains were subtyped into 46 molecular types by PFGE and 53 molecular types by cgMLST(HC2). Except for one strain belonging to ST3220, the other Salmonella Derby strains were ST40. The phylogenetic analysis showed that some strains isolated in Hangzhou were close to the strains in Southeast Asia, suggesting the possibility of cross-border transmission of ST40 strains, with the main food sources being pork and fish; other strains were close to those circulating in Beijing, Guangzhou, Hubei, Chongqing and other provinces, suggesting the possibility of cross-province transmission of the strains, with the main food sources being pork, beef and chicken. Conclusions:The epidemic of Salmonella Derby in Hangzhou was mainly caused by the spread of ST40 strains and MDR was common. Clinical infections might be closely related to the consumption of pork, beef, chicken and fish. There was the possibility of cross-border transmission of Salmonella Derby between Hangzhou and Southeast Asia and cross-province transmission in China.

Identification and phylogenetic analysis of two clinical isolates of Chryseobacterium / 中华微生物学和免疫学杂志

Objective:To analyze the biological characteristics, phylogenic features and clinical significance of SQ219 and SQ220 isolated from clinical sputum and midstream urine specimens.Methods:The culture and biochemical characteristics of the two strains were observed. VITEK2 System, drug sensitivity testing and MALDI-TOF mass spectrometry were used for bacterial identification. Phylogenetic analysis based on 16S rRNA and core genome was performed. The average nucleotide identity (ANI) based on whole genome sequences was calculated.Results:SQ219 and SQ220 were Gram-stain-negative, aerobic, catalase- and oxidase-positive, and non-motile bacteria. Their optimum growth was observed in NaCl-free medium at 30℃ and pH7. Flexirubin-type pigments were produced by SQ220 on Colombia blood agar, but not by SQ219. Both SQ219 and SQ220 were resistant to aztreonam, amikacin, tobramycin and colistin, which was consistent with the drug resistance phenotype of genus Chryseobacterium. The genome sequences of SQ219 and SQ220 were 5.08 Mb and 4.80 Mb in length, and the G+ C contents were 36.72% and 36.36%, respectively. Both strains carried β-lactam resistance gene ( blaCGA). 16S rRNA phylogenetic analysis showed that SQ219 and SQ220 were closely related to Chryseobacterium gambrini DSM18014 T with the similarities of 98.93% and 98.36%, respectively. Core genome phylogenetic analysis revealed that SQ219 and SQ220 were highly homologous to Chryseobacterium gambrini DSM18014 T. However, the ANI values between the two strains and Chryseobacterium gambrini DSM18014 T were 92.49% and 93.27%, respectively, below the threshold for prokaryotic species identification. Conclusions:Based on the phenotypic and phylogenetic data, SQ219 and SQ220 represent a novel species of the genus Chryseobacterium. This study would help promote the understanding of the evolution of Chrysobacterium and provide reference for the identification of new species of Chrysobacterium.

Analysis of the genomic landscape of primary central nervous system lymphoma using whole-genome sequencing in Chinese patients / 医学前沿

Primary central nervous system lymphoma (PCNSL) is an uncommon non-Hodgkin's lymphoma with poor prognosis. This study aimed to depict the genetic landscape of Chinese PCNSLs. Whole-genome sequencing was performed on 68 newly diagnosed Chinese PCNSL samples, whose genomic characteristics and clinicopathologic features were also analyzed. Structural variations were identified in all patients with a mean of 349, which did not significantly influence prognosis. Copy loss occurred in all samples, while gains were detected in 77.9% of the samples. The high level of copy number variations was significantly associated with poor progression-free survival (PFS) and overall survival (OS). A total of 263 genes mutated in coding regions were identified, including 6 newly discovered genes (ROBO2, KMT2C, CXCR4, MYOM2, BCLAF1, and NRXN3) detected in ⩾ 10% of the cases. CD79B mutation was significantly associated with lower PFS, TMSB4X mutation and high expression of TMSB4X protein was associated with lower OS. A prognostic risk scoring system was also established for PCNSL, which included Karnofsky performance status and six mutated genes (BRD4, EBF1, BTG1, CCND3, STAG2, and TMSB4X). Collectively, this study comprehensively reveals the genomic landscape of newly diagnosed Chinese PCNSLs, thereby enriching the present understanding of the genetic mechanisms of PCNSL.

Genome-wide characterization of three imported strains of novel coronavirus Omicron BQ.1 in Jinan,2022 / 中国人兽共患病学报

This study was aimed at understanding the genome-wide characterization and variations for three imported novel coronavirus(SARS-CoV-2)strains from different sources in the same period in Jinan at the viral genome level,to provide a sci-entific basis for further improving the prevention and control of COVID-19 outbreaks at Jinan port.We selected nasal and pha-ryngeal swab samples from three cases of imported asymptomatic COVID-19infectionat Jinan port;performed second-genera-tion whole-genome sequencing;and analyzed the variant loci and homology withvarious bioinformatics software.The whole ge-nome sequence of SARS-CoV-2 was successfully obtained from three samples of asymptomatic infected cases,and had full lengths ranging from 29 835 bp to 29 844 bp.Pangolin typing results indicated that the genotypes of the three samples were O-micron BQ.1,BQ.1.1,and BQ.1.12.Compared with the original Wuhan strain,the three samples produced mutations at 77,80,and 78 base sites,respectively,involving 60-63 non-synonymous mutations,mainly in the S and ORF1ab genes.Omicron BQ.1 is an imported variant of the SARS-CoV-2 virus and was detected for the first time at Jinan port.From a molecular biolo-gy perspective,this study provides a theoretical basis for the source tracing and prevention and control of COVID-19 at theport.

Polymyxin resistance caused by large-scale genomic inversion due to IS26 intramolecular translocation in Klebsiella pneumoniae

Polymyxin B and polymyxin E (colistin) are presently considered the last line of defense against human infections caused by multidrug-resistant Gram-negative organisms such as carbapenemase-producer Enterobacterales, Acinetobacter baumannii, and Klebsiella pneumoniae. Yet resistance to this last-line drugs is a major public health threat and is rapidly increasing. Polymyxin S2 (S2) is a polymyxin B analogue previously synthesized in our institute with obviously high antibacterial activity and lower toxicity than polymyxin B and colistin. To predict the possible resistant mechanism of S2 for wide clinical application, we experimentally induced bacterial resistant mutants and studied the preliminary resistance mechanisms. Mut-S, a resistant mutant of K. pneumoniae ATCC BAA-2146 (Kpn2146) induced by S2, was analyzed by whole genome sequencing, transcriptomics, mass spectrometry and complementation experiment. Surprisingly, large-scale genomic inversion (LSGI) of approximately 1.1 Mbp in the chromosome caused by IS26 mediated intramolecular transposition was found in Mut-S, which led to mgrB truncation, lipid A modification and hence S2 resistance. The resistance can be complemented by plasmid carrying intact mgrB. The same mechanism was also found in polymyxin B and colistin induced drug-resistant mutants of Kpn2146 (Mut-B and Mut-E, respectively). This is the first report of polymyxin resistance caused by IS26 intramolecular transposition mediated mgrB truncation in chromosome in K. pneumoniae. The findings broaden our scope of knowledge for polymyxin resistance and enriched our understanding of how bacteria can manage to survive in the presence of antibiotics.