Objective:To analyze the morphology and molecular biology and clarify the taxonomic status of one Cupriavidus species strain SZY C1 isolated from clinical wound specimens. Methods:Strain SZY C1 was subjected to physiological and biochemical identification, 16S rRNA gene sequencing, and whole genome sequencing. Its genomic features and virulence genes were analyzed using bioinformatics software.Results:Strain SZY C1 was a gram-negative, non-fermenting bacterium wihout flagella and the ability to form spores. After culturing on Columbia blood agar plates for 24 h, it formed grayish-white colonies that were round, raised, opaque, and had neatly defined margins. Based on 16S rRNA gene sequence analysis, strain SZY C1 belonged to the genus Cupriavidus with the highest 98.52% similarity to Cupriavidus metallicuns. The genome size of strain SZY C1 was determined to be 5 515 517 bp, with a G+ C content of 67.87%. Whole genome sequencing showed that strain SZY C1 had the closest phylogenetic relationship with Cupriavidus agavae, with an average nucleotide identity value of 84.76% and a digital DNA-DNA hybridization value of 29.1%, which were lower than the identification threshold for prokaryotic species. The strain SZY C1 carried multiple virulence genes, drug resistance genes, and heavy metal resistance genes. Conclusions:Based on phenotypic and genomic analyses, the strain SZY C1 is a potential new species of the Cupriavidus genus.

Objective:To analyze the biological characteristics, phylogeny and the taxonomic status of strain 7712 (=CGMCC 1.17031=NBRC 113783=KCTC 15766) isolated from a clinical blood sample.Methods:Strain 7712 was identified by the cultural properties, cellular and colonial morphology, physiological and biochemical reactions, matrix-assisted laser desorption ionization time-of-flight mass spectrometry system, and genome correlation index analysis. The genomic phylogenetic tree was construct to analyze the taxonomic position. The virulence factors and resistance genes of strain 7712 and related strains were then compared by the online virulence factor database and online comprehensive antibiotic research database respectively.Results:Strain 7712 was urease negative, gram-negative nonfermenters, which was identified as Ochrobactrum anthropi by VITEK GN card. The 16S rRNA gene analysis showed that the strain was closely related to the members of genera Ochrobactrum and Brucella. The phylogenetic tree showed that strain 7712 was clustered together with Ochrobactrum teleogrylli LCB8 T and Ochrobactrum haematophilum CCUG 38531 T, along with genus Brucella and other Ochrobactrum species. The genome relatedness indexes analysis showed that the average nucleotide identity between strain 7712 and Ochrobactrum teleogrylli LCB8 T was 98.16%, which was higher than the threshold for prokaryotic species. Genetic prediction showed that strain 7712 carried several virulence-related genes and resistance-related genes, of which the existence of OCH gene might be responsible to the resistance to cephalosporin. Conclusions:A case of human infection caused by Ochrobactrum teleogrylli is identified, which would help promote the understanding of biodiversity of genus Ochrobactrum.

Objective:To identify and characterize one Spiroplasma strain (designated as DGKH1) isolated from the blood of a patient with sepsis. Methods:The traditional bacterial culture, staining, morphological observation, physiological and biochemical identification, 16S rRNA gene sequencing, phylogenetic analysis, genome sequencing, and the genome-related index analysis were performed to accurately determine the taxonomic status of the strain DGKH1. Antibiotic susceptibility testing was performed using a specific kit for culturing and testing Ureaplasma urealyticum/ Metamycoplasma hominis. Results:The strain DGKH1 could weakly grow on Columbia blood agar, chocolate agar, and Haemophilus chocolate 2 agar. However, it did not grow in liquid culture medium containing tetracycline (4 μg/ml), doxycycline (1 μg/ml), minocycline (1 μg/ml), josamycin (2 μg/ml), roxithromycin (1 μg/ml), clarithromycin (1 μg/ml), or telithromycin (1 μg/ml). DGKH1 resembling Metamycoplasma hominis formed "fried egg-like colonies" on Mycoplasma solid culture medium. DGKH1 could not be stained by Gram staining. When observed under transmission electron microscopy (TEM) using phosphate buffer as the matrix, the bacteria were spiral-shaped. Results of 16S rRNA gene sequence alignment showed that DGKH1 was highly similar (99.85%) to Spiroplasma eriocheiris CCTCC M 207170 T. However, the urea decomposition test was positive, which was different from all of the known Spiroplasma species. The phylogenetic analysis based on whole genome showed that DGKH1 was clustered in a small branch along with Spiroplasma eriocheiris CCTCC M 207170 T. However, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 94.14% and 56.00%, respectively, both below the threshold for prokaryotic species identification. Conclusions:DGKH1 represented a potential new species of genus Spiroplasma, closely related to Spiroplasma eriocheiris. Some microbiological characteristics of DGKH1 were similar to Mycoplasmas. However, the natural host and epidemiological data of DGKH1 need to be further studied.

Objective:To analyze the molecular epidemiological characteristics of Campylobacter fetus subsp. testudinum ( Cft). Methods:Fifteen strains of Cft collected in our laboratory from 2010 to 2022 were subjected to whole-genome sequencing. Their epidemiological characteristics were analyzed based on the global genome data of Cft on GenBank database. MLST-GrapeTree software was used to obtain the genetic structure of Cft strains. A phylogenetic tree was constructed using core-genome single nucleotide polymorphism (cgSNP) analysis, and the sequence clusters were identified using rhierBAPS. Virulence genes and drug resistance genes of Cft strains were annotated using CARD, ResFinder and VFDB database. Their susceptibility to antibiotics was tested using E-test method and the results were analyzed using the CLSI-M45 sensitivity standard for Campylobacter jejuni/ Campylobacter coli. Results:Based on average nucleotide identity (ANI) analysis, the genome data of 41 Cft strains including 24 isolated from human, 13 from animals and four of unknown sources were collected from GenBank database. Among the 24 human-derived strains, 20 were linked to Asian descent and only one was linked to Caucasian descent (spouse of Asian descent), showing statistically significant differences in human ethnicity. All of the 13 animal-derived strains were originated from reptilian sources, including six from turtles, four from snakes and three from lizards. MLST revealed that ST46 was the predominant ST in China, while ST15 was the major sequence type in the United States. Grapetree analysis also demonstrated that the genetic diversity in China was greater than that in the United States. The phylogenetic tree constructed based on cgSNP and BAPS identified six distinct sequence clusters. The Chinese isolates were scattered in diverse sequence clusters and closely related to animal-derived strains, while the American isolates mainly belonged to ST15. The genes encoding virulence factors such as flagella, glycosylation systems and adhesins were carried by all of the 41 Cft strains (100.00%). The invasion-related virulence genes, such as the genes encoding the IV type secretion system ( virB4, virB9, virD4) and the resistance-related tetO efflux pump gene were specifically identified in the emerging ST74 clones. In vitro drug susceptibility testing of 15 Chinese isolates revealed 46.67% of the Cft strains were resistant to ciprofloxacin and 100.00% were sensitive to erythromycin. Conclusions:The global sequence clusters of Cft isolates showed a great genetic diversity. Most of the people with Cft infection had basic immune diseases and might have eaten or had contact with reptiles. Notably, the Chinese domestic infection of ST46 and the emerging ST74 should arouse our more attention.

Objective:To identify and characterize two Balneatrix alpica strains isolated from a patient′s blood sample (strain X117) and the natural hot spring water in the patient′s residential district (strain GN-1), and to provide experimental evidence for the pathogenic diagnosis of clinical infection caused by this rare pathogen. Methods:Biochemical phenotypic identification, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), 16S rRNA gene sequencing, phylogenetic analysis, single-nucleotide polymorphism (SNP) analysis, and genome-wide analysis were performed to accurately determine the taxonomic status of the isolates X117 and GN-1 by using Balneatrix alpica DSM 16621 T as a reference. Microdilution broth method was used to test their antimicrobial susceptibility. The virulence genes carried by them were annotated and analyzed using the virulence factor database (VFDB). Results:Strains X117 and GN-1 formed light yellow or tan colonies with mottled surfaces on Columbia blood agar and chocolate agar plates after 4 d of culture. They were Gram-negative rods and positive for oxidase and indole tests, which were consistent with the characteristics of Balneatrix alpica DSM 16621 T. The phylogenetic analysis based on the 16S rRNA gene showed that the isolates X117 and GN-1 were both Balneatrix alpaca. The average nucleotide identity (ANI) values between the two isolates and Balneatrix alpica DSM 16621 T were 98.44% and 98.41%, respectively, and the digital DNA-DNA hybridization (dDDH) values were both 87.1%. The SNP distance between the two strains was 13, indicating that X117 and GN-1 might belong to the same clone. The antibiotic susceptibility testing showed that all of the three Balneatrix alpica strains were sensitive to the commonly used antibiotics against Gram-negative rods. The virulence genes carried by the three Balneatrix alpica strains were mainly involved in adhesion, invasion, flagella and biofilm formation. Conclusions:This study identified a case of bloodstream infection caused by Balneatrix alpica which was closely related to natural hot spring water. Natural hot spring water migh be an important source of clinical infections caused by this species.

Objective:To study the molecular phylogeny and virulence gene profile of Francisella salimarina. Methods:Phylogenetic analysis of Francisella salimarina was performed based on the global genome data of related Francisella species on GenBank database. The consistency in phylogenetic analysis based on single marker genes (such as 16S rRNA gene, rpoB gene and mdh gene) and the core genome as compared. Virulence genes and antibiotic resistance genes were annotated using the virulence factor database (VFDB) and the Comprehensive Antibiotic Resistance Database (CARD), respectively. The virulence of Francisella salimarina was analyzed with a Galleria mellonella (greater wax moth) infection model using Francisella philomiragia ATCC 25015 T as reference strain. Results:The phylogenetic analysis revealed that Francisella salimarina was closely related to Francisella philomiragia. The phylogenetic tree based on mdh gene was highly similar to that based on the core genome. Francisella salimarina could be differentiated from other related species by 16S rRNA gene or mdh gene, with the latter being more accurate. Eight Francisella salimarina strains carried multiple virulence genes, mainly involved in secretion, adhesion, immune regulation, motility and stress survival. Moreover, beta-lactam resistance gene blaFPH was identified in all eight strains. Francisella salimarina showed high lethality in the Galleria mellonella infection model, which was similar to Francisella philomiragia ATCC 25015 T. Conclusions:Francisella salimarina was a rare pathogen with similar pathogenicity to Francisella philomiragia. The mdh gene could be used as a molecular target for rapid identification of Francisella salimarina.

Objective:To identify a pathogenic strain JM-1 isolated from the pus of a patient stabbed by a sea shrimp and to analyze its antibiotic susceptibility and virulence genes, aiming to provide reference for screening clinically related infections caused by Cysteiniphilum litorale as a rare pathogen and improving prognosis. Methods:Biochemical phenotype identification, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), 16S rRNA gene sequencing, analysis of average nucleotide identity (ANI) and average amino acid identity (AAI) based on the whole genome and phylogenetic analysis of the 16S rRNA gene and the whole genome were performed to accurately determine the taxonomic status of the strain JM-1. E-test was used to detect antibiotic susceptibility, and the results were interpreted according to the interpretation standards of Francisella tularensis in CLSI M45-A3. The virulence factor database (VFDB) was used for genome-wide annotation and analysis of virulence genes. Results:After culturing the strain JM-1 on the Columbia blood plate for 3 d, some grey-white, medium-sized, smooth, round and convex hemolytic colonies were observed. Gram staining result showed lightly colored Gram-negative Coccobacillus. API NH identification results suggested that the isolate JM-1 was Moraxella catarrhalis (biochemical code: 3010), while there was no identification result in Vitek2 system NH card (biochemical code: 0211002121). The EXS3000 mass spectrometer self-built database identified the isolate JM-1 as Cysteiniphilum litorale. The phylogenetic analysis based on the 16S rRNA gene and the whole genome showed that the isolate JM-1 and Cysteiniphilum litorale DSM 101832 T clustered into the same branch, and the ANI and AAI values between the two strains were 95.07% and 95.65%, respectively. The biochemical phenotype identification indicated the isolate JM-1 producing β-lactamase and penicillinase. Antibiotic susceptibility test results showed the strain was resistant to penicillin and sensitive to gentamicin, streptomycin, doxycycline, tetracycline, ciprofloxacin, levofloxacin, and chloramphenicol. Genome annotation suggested the virulence genes of the isolate JM-1 were similar to those of Francisella, including Francisella pathogenicity island (FPI), type Ⅳ fimbriae, capsule and lipopolysaccharide. Conclusions:Cysteiniphilum litorale was a rare pathogen with virulence genes similar to those of Francisella, and its antibiotic susceptibility was also similar to that of Francisella. This study confirmed a case of clinical infection caused by Cysteiniphilum litorale. The self-built MALDI-TOF MS system could be used for its rapid identification.

Atopic dermatitis (AD) is a chronic, relapsable and pruritic skin disease, commonly found in children and adolescents. The prevalence of AD is increasing worldwide. It is reported that AD is related to many factors such as genetic inheritance, environment, immunity and skin barrier dysfunction, suggesting a very complex pathogenesis. In recent years, high-throughput technologies in the field of genomics and metabolomics have opened up new perspectives on the pathogenesis of AD, and shown potential application prospects in microbiome transplantation therapies for AD. This review summarized the current advances in the relationship between skin microecology and skin health, the pathogenesis and microbiomic characteristics of AD, features of pathogenic microorganisms, and microbiome transplantation therapies for AD. Based on our own practical experience, we put forward a culturomics research protocol to study the human skin microbiome and a method for quantitative microbiological examination, aiming to provide reference for the prevention, clinical treatment and therapeutic monitoring of AD.

Objective: To identify and characterize the 4 strains of Prototheca isolated from the clinical samples of skin or ascites samples in China. Methods: The taxonomic position of 4 yeast-like organisms was revealed by polyphasic taxonomic approach, i.e., cultural and morphologic characteristics, commercial biochemical systems of Vitek 2 (YST kit) and Vitek matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS) systems in combination with phylogenetic analysis based on the gene sequences of 16S and 28S rRNA. Results: The 4 strains of Prototheca were characterized as cream-white, smooth, moist yeast-like colonies on Sabouraud gentamicin chloramph agar after incubation for 3 days. However, round, oval-shaped or elliptical sporangiums with mulberry-like or strawberry-like endospores were observed by optical microscope, which showed distinct differences from the general yeast species. The 4 isolates were identified as Prototheca wickerhamii with Vitek YST kits by Vitek 2 systems and Vitek MALDI-TOF MS systems. The genome for the 4 isolates was characterized with the existence of the prokaryotic 16S rRNA gene and eukaryotic 28S rRNA gene. The 16S rRNA gene sequence of the 4 strains showed more than 99.7% similarity to that of P. wickerhamii. Sequence analysis of 28S rRNA gene showed that the organisms included multiple copies of different sequences, which showed sequence similarities of 91.9% to 100% even in the same strain. The phylogenetic dendrogram based on 16S rRNA and 28S rRNA gene sequences showed that the 4 strains of Prototheca formed a cluster along with P. wickerhamii. Conclusion The 4 yeast-like organisms could be identified as P. wickerhamii, and 16S rRNA gene should be the suitable molecular target for the identification.

Objective: Establishing the mass spectrum library of a new Campylobacter- " C.fetus subsp.testudinum" for rapid species identification in clinical microbiology laboratory. Methods: Illumina second generation sequencing platform 2000/miSeq was used to carry out high flux genome sequencing for the strains which were collected to establish mass spectrum library.The analysis oforthologous average nucleotide identity (OrthoANI) between collected strains and reference strains was performed at JAVA 8 operation environment. Then, the mass spectrums ofcollected strains andreference strains were acquired using MALDI-TOF MS. And the mass spectrum library of C. fetus subsp.testudinum. were established and verified. Results: The OrthoANI analysis showed that the OrthoANI value of the collected strains and the reference strain C. fetus subsp.testudinum03-427 was 99.30%-99.96%, while the OrthoANI values of collected strains and C. fetus subsp.venerealisNCTC10354 orC.fetus subsp.fetus82-40 were 91.05%-92.26%. With reference to OrthoANI ≥ 95% as the basis for the determination of the same strain, the strains which collected to establish mass spectrum library was finally identified as " C. fetus subsp.testudinum" . The identification accuracy rate of the mass spectrum library was 100% (consistent with gene sequencing), and the confidence interval was 82.3%-99.9%, identification of the same strain is 100% reproducible. Conclusions The new" gold standard" based on high throughput sequencing and total genome analysis has provided the ideal reference value for the establishment of mass spectrum library.And the accurate and objective reference spectrum of the" C.fetus subsp.testudinum" provides a new platform for the rapid diagnosis of fetal Campylobacter infection. (Chin J Lab Med, 2018, 41: 583-588)