Laboratory Study on the Gastroenteritis Outbreak Caused by a Multidrug-Resistant Campylobacter coli in China.

Three severe acute gastroenteritis patients were identified within a 5-h period in a sentinel hospital enrolled in the foodborne pathogen surveillance project in Beijing. All patients had high fever (over 38.5°C), diarrhea, abdominal pain, vomiting, and headache. Ten grams of fresh patient stool sample and 25 g of six suspected foods were collected for real-time PCR screening for 10 major pathogens. Bacterial isolation was performed. Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and antibiotic susceptibility tests were conducted for all the isolates. Whole-genome sequences of the three Campylobacter coli isolates were compared using whole-genome MLST. All stool samples were positive for C. coli, as revealed by PCR. Eleven of the C. coli isolates had the same PFGE and ST type. All isolates were resistant to nalidixic acid, ciprofloxacin, streptomycin, and tetracycline, consistent with the findings of the in silico antibiotic resistance gene profiling. Most coding sequences (99%, 1736/1739) were identical among the three sequenced isolates, except for three frameshift-mutated genes caused by the simple sequence repeats (poly-Gs). This was likely a single-source outbreak caused by a group of highly clonal C. coli. This was the first outbreak of severe gastroenteritis caused by C. coli in China.

Comparison of Pathogenicity of Invasive and Carried Meningococcal Isolates of ST-4821 Complex in China.

Serotype 4821 (ST-4821) clonal complex (cc4821) Neisseria meningitidis strains are divided into two groups (groups I and II) according to the core genome-based phylogenetic analysis. Group I contains the greater number of invasive disease isolates. However, the differences in pathogenicity between the two groups are unclear. In this study, the pathogenicity of cc4821 isolates (n = 28) belonging to group I and group II (each containing eight invasive isolates and six isolates from healthy carriers) was investigated, including adhesion, invasion, and induction of interleukin-6 (IL-6) and interleukin-8 (IL-8) release from host cells (Hep2 and A549). The invasive isolates had higher adhesion and invasion capabilities than the carried isolates in both groups. The carried cc4821 isolates in group I had stronger invasion capability than those in group II. Invasive isolates induced more IL-6 and IL-8 secretion than carried isolates in both groups. The carried cc4821 isolates stimulated higher levels of IL-8 in group I than in group II. The isolates were defined as hyperadherent and hypoadherent groups according to their adhesion ability and as hyperinvasive and hypoinvasive groups based on their invasion ability. The hyperadherent and hyperinvasive isolates mediated more IL-6 and IL-8 release than the hypoadherent and hypoinvasive isolates. There was no difference in the level of cytokine release when cc4821 isolates lost their adhesion and invasion capability after lysis. The results revealed that differences in pathogenicity existed between the two groups and that the differences were mainly determined by differences in adhesion and invasion capabilities.

The Molecular Mechanisms of Ciprofloxacin Resistance in Clinical Campylobacter jejuni and Their Genotyping Characteristics in Beijing, China.

We assessed the susceptibility of 182 Campylobacter jejuni isolates from patients with diarrhea to eight antibiotics and analyzed the molecular mechanisms of ciprofloxacin resistance as well as the genetic characteristics based on multilocus sequence typing (MLST). The C257T mutation was found on the quinolone resistance-determining region (QRDR) of the gyrA gene in all ciprofloxacin-resistant strains. Mutations on the QRDR of the gyrB gene were silent. A total of 74 strains had 7 inverted repeat (IR) (a 16-bp IR on the intergenic region between cmeR and cmeABC) mutation polymorphisms. Compared with strains without the IR mutations, strains with the IR mutations had higher resistance rates to ciprofloxacin (94.6% vs. 83.3%), nalidixic acid (94.6% vs. 83.3%), tetracycline (98.6% vs. 85.2%), doxycycline (91.9% vs. 71.3%), florfenicol (59.5% vs. 17.6%), chloramphenicol (25.7% vs. 4.6%), gentamicin (16.2% vs. 3.7%), and multidrug resistance than those without IR mutations (all p < 0.05). With C257T mutation alone, 89.9% strains with minimum inhibitory concentration (MIC) values focused on 16, 32, and 64 µg/mL, whereas strains with C257T mutation in combination with the IR mutations had a higher ciprofloxacin resistance level with 88.6% MIC values focused on 64, 128, and 512 µg/mL (p < 0.0001). The strains in this study showed a high genetic variability based on MLST with 117 sequence types (STs), 37 of which were novel. CC-21 was the most common clonal complex (CC) followed by CC-353 and CC-45. No association was found between STs and ciprofloxacin resistance. In conclusion, the C257T mutation on gyrA was the major mechanism for ciprofloxacin resistance, and the C257T mutation in combination with the IR mutations might result in more severe ciprofloxacin resistance to C. jejuni.

Constitutive and Inducible Expression of the rRNA Methylase Gene erm(B) in Campylobacter.

Macrolides are the antimicrobials of choice for treating human campylobacteriosis. The recent emergence of erm(B) in Campylobacter bacteria threatens the utility of this class of antibiotics. Here we report the constitutive and inducible expression of erm(B) in Campylobacter isolates derived from diarrheal patients and food-producing animals. Constitutive expression of erm(B) was associated with insertion and deletion in the regulatory region of the gene, providing the first documentation of the differential expression of erm(B) in Campylobacter bacteria.

Emergence of multidrug-resistant Campylobacter species isolates with a horizontally acquired rRNA methylase.

Antibiotic-resistant Campylobacter constitutes a serious threat to public health, and resistance to macrolides is of particular concern, as this class of antibiotics is the drug of choice for clinical therapy of campylobacteriosis. Very recently, a horizontally transferrable macrolide resistance mediated by the rRNA methylase gene erm(B) was reported in a Campylobacter coli isolate, but little is known about the dissemination of erm(B) among Campylobacter isolates and the association of erm(B)-carrying isolates with clinical disease. To address this question and facilitate the control of antibiotic-resistant Campylobacter, we determined the distribution of erm(B) in 1,554 C. coli and Campylobacter jejuni isolates derived from food-producing animals and clinically confirmed human diarrheal cases. The results revealed that 58 of the examined isolates harbored erm(B) and exhibited high-level resistance to macrolides, and most were recent isolates, derived in 2011-2012. In addition, the erm(B)-positive isolates were all resistant to fluoroquinolones, another clinically important antibiotic used for treating campylobacteriosis. The erm(B) gene is found to be associated with chromosomal multidrug resistance genomic islands (MDRGIs) of Gram-positive origin or with plasmids of various sizes. All MDRGIs were transferrable to macrolide-susceptible C. jejuni by natural transformation under laboratory conditions. Molecular typing of the erm(B)-carrying isolates by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) identified diverse genotypes and outbreak-associated diarrheal isolates. Molecular typing also suggested zoonotic transmission of erm(B)-positive Campylobacter. These findings reveal an emerging and alarming trend of dissemination of erm(B) and MDRGIs in Campylobacter and underscore the need for heightened efforts to control their further spread.

Report of ribosomal RNA methylase gene erm(B) in multidrug-resistant Campylobacter coli.

OBJECTIVES: Campylobacter is a major foodborne enteric pathogen and macrolides are the drug of choice for the clinical therapy of campylobacteriosis. Macrolide resistance among Campylobacter compromises clinical treatment, is associated with adverse health events and is a significant public health concern. Here, we report the first identification of a horizontally transferrable macrolide resistance mechanism in porcine Campylobacter coli ZC113 that is mediated by a ribosomal RNA methylase, Erm(B). METHODS: Horizontal transfer of a macrolide resistance determinant between C. coli and Campylobacter jejuni was performed by natural transformation. Whole-genome sequencing was initially used to identify the ribosomal methylase-encoding gene erm(B) in Campylobacter. Cloning of erm(B) into C. jejuni NCTC 11168 was performed to evaluate whether the erm(B) gene is responsible for high-level macrolide resistance in Campylobacter. RESULTS: The erm(B) gene was identified in ZC113, conferred high-level resistance to macrolides and was associated with a chromosomal multidrug-resistant genomic island (MDRGI). The MDRGI probably originated from Gram-positive bacteria and was horizontally transferred between C. coli and C. jejuni via natural transformation. Furthermore, the erm(B)-positive isolate ZC113 was resistant to all clinically important antibiotics used for treating campylobacteriosis and is essentially multidrug-resistant Campylobacter. CONCLUSIONS: To the best of our knowledge, this is the first report of a horizontally transferable macrolide resistance mechanism in thermophilic Campylobacter. Surveillance of erm(B) and its associated MDRGI in both C. coli and C. jejuni is urgently warranted.

Super-resolution fusion of complementary panoramic images based on cross-selection kernel regression interpolation.

A complementary catadioptric imaging technique was proposed to solve the problem of low and nonuniform resolution in omnidirectional imaging. To enhance this research, our paper focuses on how to generate a high-resolution panoramic image from the captured omnidirectional image. To avoid the interference between the inner and outer images while fusing the two complementary views, a cross-selection kernel regression method is proposed. First, in view of the complementarity of sampling resolution in the tangential and radial directions between the inner and the outer images, respectively, the horizontal gradients in the expected panoramic image are estimated based on the scattered neighboring pixels mapped from the outer, while the vertical gradients are estimated using the inner image. Then, the size and shape of the regression kernel are adaptively steered based on the local gradients. Furthermore, the neighboring pixels in the next interpolation step of kernel regression are also selected based on the comparison between the horizontal and vertical gradients. In simulation and real-image experiments, the proposed method outperforms existing kernel regression methods and our previous wavelet-based fusion method in terms of both visual quality and objective evaluation.

Molecular subtyping and antimicrobial susceptibilities of Campylobacter coli isolates from diarrheal patients and food-producing animals in China.

The aim of this study was to determine the molecular subtyping and antimicrobial susceptibility characteristics of Campylobacter coli isolates from different sources in China. One hundred thirteen C. coli isolates were subtyped by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and porA and flaA short variable region (SVR) nucleotide sequences. Cluster analysis was performed based on the PFGE and sequence types (ST). Eighty-four PFGE patterns (SmaI) were observed in 113 isolates. Fifty-four STs (28 novel) and three clonal complexes (CC), 86% of which were clustered to CC828, were observed, as well as 52 porA and 37 flaA-SVR sequence alleles. MLST, porA, and flaA-SVR analysis demonstrated that many isolates from diarrheal patients shared identical genotypes with chicken isolates. Minimum inhibitory concentration values of 10 antibiotics were analyzed for 109 isolates isolated in 2011 using the E-test method. The most frequently observed resistance agents were nalidixic acid (100%) and ciprofloxacin (100%), followed by levofloxacin (99%), tetracycline (94%), metronidazole (93%), erythromycin (61%), streptomycin (72%), gentamicin (59%), ampicillin (50%), and chloramphenicol (29%). Multidrug resistance was detected in 108 of 109 C. coli isolates (99%).

Green channel guiding denoising on bayer image.

Denoising is an indispensable function for digital cameras. In respect that noise is diffused during the demosaicking, the denoising ought to work directly on bayer data. The difficulty of denoising on bayer image is the interlaced mosaic pattern of red, green, and blue. Guided filter is a novel time efficient explicit filter kernel which can incorporate additional information from the guidance image, but it is still not applied for bayer image. In this work, we observe that the green channel of bayer mode is higher in both sampling rate and Signal-to-Noise Ratio (SNR) than the red and blue ones. Therefore the green channel can be used to guide denoising. This kind of guidance integrates the different color channels together. Experiments on both actual and simulated bayer images indicate that green channel acts well as the guidance signal, and the proposed method is competitive with other popular filter kernel denoising methods.

Context-aware and locality-constrained coding for image categorization.

Improving the coding strategy for BOF (Bag-of-Features) based feature design has drawn increasing attention in recent image categorization works. However, the ambiguity in coding procedure still impedes its further development. In this paper, we introduce a context-aware and locality-constrained Coding (CALC) approach with context information for describing objects in a discriminative way. It is generally achieved by learning a word-to-word cooccurrence prior to imposing context information over locality-constrained coding. Firstly, the local context of each category is evaluated by learning a word-to-word cooccurrence matrix representing the spatial distribution of local features in neighbor region. Then, the learned cooccurrence matrix is used for measuring the context distance between local features and code words. Finally, a coding strategy simultaneously considers locality in feature space and context space, while introducing the weight of feature is proposed. This novel coding strategy not only semantically preserves the information in coding, but also has the ability to alleviate the noise distortion of each class. Extensive experiments on several available datasets (Scene-15, Caltech101, and Caltech256) are conducted to validate the superiority of our algorithm by comparing it with baselines and recent published methods. Experimental results show that our method significantly improves the performance of baselines and achieves comparable and even better performance with the state of the arts.

A master-slave surveillance system to acquire panoramic and multiscale videos.

This paper describes a master-slave visual surveillance system that uses stationary-dynamic camera assemblies to achieve wide field of view and selective focus of interest. In this system, the fish-eye panoramic camera is capable of monitoring a large area, and the PTZ dome camera has high mobility and zoom ability. In order to achieve the precise interaction, preprocessing spatial calibration between these two cameras is required. This paper introduces a novel calibration approach to automatically calculate a transformation matrix model between two coordinate systems by matching feature points. In addition, a distortion correction method based on Midpoint Circle Algorithm is proposed to handle obvious horizontal distortion in the captured panoramic image. Experimental results using realistic scenes have demonstrated the efficiency and applicability of the system with real-time surveillance.

Extensive Genetic Diversity and Epidemiological Patterns of Factor H-Binding Protein Variants among Neisseria meningitidis in China.

Factor H-binding protein (fHbp) is a virulence factor expressed by Neisseria meningitidis (N. meningitidis), the primary causative agent of invasive meningococcal disease (IMD) in humans. fHbp is utilized as the main component in vaccines to provide protection against IMD caused by serogroup B N. meningitidis. In order to comprehensively investigate the genetic diversity and epidemiological patterns of fHbp variants within isolates of Chinese N. meningitidis, we utilized the NEIS0349 locus, which encompasses the complete coding sequences of fHbp. This enabled us to identify allelic variants of fHbp with enhanced resolution. A total of 109 fHbp variants were identified in 1013 Chinese N. meningitidis isolates. We reconstructed a phylogenetic tree and analyzed the epidemiological characteristics of each variant. Considering both temporal and geographical distribution patterns, only four fHbp variants (v2.16, v2.18, v2.404, and v2.21) exhibited persistent nationwide prevalence during the previous decade (2011-2021). These variants were highly prevalent in both serogroup B strains from patients and healthy individuals, suggesting their potential as suitable vaccine candidates for nationwide implementation against IMD caused by serogroup B strains. Our study emphasizes the significance of conducting continuous surveillance of meningococcal strains to monitor the genetic diversity of fHbp for the purpose of vaccine development.

Identification of pneumococcal serotypes with individual recognition of vaccine types by a highly multiplexed real-time PCR-based MeltArray approach.

BACKGROUND: Pneumococcus serotyping is important for monitoring serotype epidemiology, vaccine-induced serotypes replacement and emerging pathogenic serotypes. However, the lack of high-resolution serotyping tools has hindered its widespread implementation. METHODS: We devised a single-step, multiplex real-time polymerase chain reaction (PCR)-based MeltArray approach termed PneumoSero that can identify 92 serotypes with individual recognition of 54 serotypes, including all 24 currently available vaccine types. The limit of detection (LOD) and the ability to coexisting serotypes were studied, followed by analytical evaluation using 92 reference pneumococcal strains and 125 non-pneumococcal strains, and clinical evaluation using 471 pneumococcus isolates and 46 pneumococcus-positive clinical samples. RESULTS: The LODs varied with serotypes from 50 to 100 copies per reaction and 10 % of the minor serotypes were detectable in samples containing two mixed serotypes. Analytical evaluation presented 100 % accuracy in both 92 reference pneumococcal strains and 125 non-pneumococcal strains. Clinical evaluation of 471 pneumococcus isolates displayed full concordance with Sanger sequencing results. The 46 clinical specimens yielded 45 typeable results and one untypeable result. Of the 45 typeable samples, 41 were of a single serotype and four were of mixed serotypes, all of which were confirmed by Sanger sequencing or separate PCR assays. CONCLUSION: We conclude that the PneumoSero assay can be implemented as a routine tool for pneumococcal serotyping in standard microbiology laboratories and even in clinical settings.

Emergence of Erythromycin-Resistant and Pertactin- and Filamentous Hemagglutinin-Deficient Bordetella pertussis Strains - Beijing, China, 2022-2023.

What is already known about this topic?: Pertussis has reemerged as a significant public health threat, primarily due to variations in Bordetella pertussis strains, antimicrobial resistance, and vaccine evasion. What is added by this report?: All isolated strains were identified as ptxA1/ptxC2/ptxP3/prn150/fim2-1/fim3-1/fhaB1/tcfA2 type and exhibited resistance to erythromycin. Two strains showed a deficiency in Fha, thirty in Prn, and one strain exhibited multiple immunogen deficiencies. What are the implications for public health practice?: The emergence and spread of immunogen-deficient strains likely result from prolonged vaccine selection pressure, posing challenges to the efficacy of pertussis vaccines. Additionally, the ongoing dissemination of ptxP3 strains with high-level macrolide resistance presents a significant obstacle to clinical treatment strategies.

Genetic characteristics and potential pathogenic agents in Campylobacter upsaliensis based on genomic analysis.

Campylobacter upsaliensis was the most common Campylobacter species in pets' gastrointestinal tracts and has been isolated from patients with bacteremia, hemolytic-uremic syndrome, spontaneous abortion, and Guillain-Barré syndrome. However, the genetic characteristics and the full extent of its significance as a human pathogen remain to be fully understood. This study involved an investigation for genomic analysis of 154 strains from different sources and additional antimicrobial resistance profiles of 26 strains for this species. The genomes contained 1,558-1,971 CDS and the genome sizes were estimated to vary from 1.53 Mb to 1.86 Mb, with an average GC content of 34.71%. The entire analyzed genomes could be divided into three clades (A, B, and C) based on ANI and phylogenomic analysis. Significantly, nearly all strains in Clade B were isolated from patient samples, and the virulence-related sequences FlgD, GmhA, and CdtC might serve as determining factors for the classification of Clade B. Half of the tested isolates had MIC values over 64 µg mL-1 for nalidixic acid, gentamicin, and streptomycin. Isolates from pets in China carried more resistant elements in the genomes. This study both provided a comprehensive profile of C. upsaliensis for its genomic features and suggested some pathogenic agents for human infection with this species.

Multi-scale locality-constrained spatiotemporal coding for local feature based human action recognition.

We propose a Multiscale Locality-Constrained Spatiotemporal Coding (MLSC) method to improve the traditional bag of features (BoF) algorithm which ignores the spatiotemporal relationship of local features for human action recognition in video. To model this spatiotemporal relationship, MLSC involves the spatiotemporal position of local feature into feature coding processing. It projects local features into a sub space-time-volume (sub-STV) and encodes them with a locality-constrained linear coding. A group of sub-STV features obtained from one video with MLSC and max-pooling are used to classify this video. In classification stage, the Locality-Constrained Group Sparse Representation (LGSR) is adopted to utilize the intrinsic group information of these sub-STV features. The experimental results on KTH, Weizmann, and UCF sports datasets show that our method achieves better performance than the competing local spatiotemporal feature-based human action recognition methods.

Video denoising based on a spatiotemporal Kalman-bilateral mixture model.

We propose a video denoising method based on a spatiotemporal Kalman-bilateral mixture model to reduce the noise in video sequences that are captured with low light. To take full advantage of the strong spatiotemporal correlations of neighboring frames, motion estimation is first performed on video frames consisting of previously denoised frames and the current noisy frame by using block-matching method. Then, current noisy frame is processed in temporal domain and spatial domain by using Kalman filter and bilateral filter, respectively. Finally, by weighting the denoised frames from Kalman filtering and bilateral filtering, we can obtain a satisfactory result. Experimental results show that the performance of our proposed method is competitive when compared with state-of-the-art video denoising algorithms based on both peak signal-to-noise-ratio and structural similarity evaluations.

A novel adaptive cubic quasi-Newton optimizer for deep learning based medical image analysis tasks, validated on detection of COVID-19 and segmentation for COVID-19 lung infection, liver tumor, and optic disc/cup.

BACKGROUND: Most of existing deep learning research in medical image analysis is focused on networks with stronger performance. These networks have achieved success, while their architectures are complex and even contain massive parameters ranging from thousands to millions in numbers. The nature of high dimension and nonconvex makes it easy to train a suboptimal model through the popular stochastic first-order optimizers, which only use gradient information. PURPOSE: Our purpose is to design an adaptive cubic quasi-Newton optimizer, which could help to escape from suboptimal solution and improve the performance of deep neural networks on four medical image analysis tasks including: detection of COVID-19, COVID-19 lung infection segmentation, liver tumor segmentation, optic disc/cup segmentation. METHODS: In this work, we introduce a novel adaptive cubic quasi-Newton optimizer with high-order moment (termed ACQN-H) for medical image analysis. The optimizer dynamically captures the curvature of the loss function by diagonally approximated Hessian and the norm of difference between previous two estimates, which helps to escape from saddle points more efficiently. In addition, to reduce the variance introduced by the stochastic nature of the problem, ACQN-H hires high-order moment through exponential moving average on iteratively calculated approximated Hessian matrix. Extensive experiments are performed to access the performance of ACQN-H. These include detection of COVID-19 using COVID-Net on dataset COVID-chestxray, which contains 16 565 training samples and 1841 test samples; COVID-19 lung infection segmentation using Inf-Net on COVID-CT, which contains 45, 5, and 5 computer tomography (CT) images for training, validation, and testing, respectively; liver tumor segmentation using ResUNet on LiTS2017, which consists of 50 622 abdominal scan images for training and 26 608 images for testing; optic disc/cup segmentation using MRNet on RIGA, which has 655 color fundus images for training and 95 for testing. The results are compared with commonly used stochastic first-order optimizers such as Adam, SGD, and AdaBound, and recently proposed stochastic quasi-Newton optimizer Apollo. In task detection of COVID-19, we use classification accuracy as the evaluation metric. For the other three medical image segmentation tasks, seven commonly used evaluation metrics are utilized, that is, Dice, structure measure, enhanced-alignment measure (EM), mean absolute error (MAE), intersection over union (IoU), true positive rate (TPR), and true negative rate. RESULTS: Experiments on four tasks show that ACQN-H achieves improvements over other stochastic optimizers: (1) comparing with AdaBound, ACQN-H achieves 0.49%, 0.11%, and 0.70% higher accuracy on the COVID-chestxray dataset using network COVID-Net with VGG16, ResNet50 and DenseNet121 as backbones, respectively; (2) ACQN-H has the best scores in terms of evaluation metrics Dice, TPR, EM, and MAE on COVID-CT dataset using network Inf-Net. Particularly, ACQN-H achieves 1.0% better Dice as compared to Apollo; (3) ACQN-H achieves the best results on LiTS2017 dataset using network ResUNet, and outperforms Adam in terms of Dice by 2.3%; (4) ACQN-H improves the performance of network MRNet on RIGA dataset, and achieves 0.5% and 1.0% better scores on cup segmentation for Dice and IoU, respectively, compared with SGD. We also present fivefold validation results of four tasks. It can be found that the results on detection of COVID-19, liver tumor segmentation and optic disc/cup segmentation can achieve high performance with low variance. For COVID-19 lung infection segmentation, the variance on test set is much larger than on validation set, which may due to small size of dataset. CONCLUSIONS: The proposed optimizer ACQN-H has been validated on four medical image analysis tasks including: detection of COVID-19 using COVID-Net on COVID-chestxray, COVID-19 lung infection segmentation using Inf-Net on COVID-CT, liver tumor segmentation using ResUNet on LiTS2017, optic disc/cup segmentation using MRNet on RIGA. Experiments show that ACQN-H can achieve some performance improvement. Moreover, the work is expected to boost the performance of existing deep learning networks in medical image analysis.

Helicobacter zhangjianzhongii sp. nov., isolated from dog feces.

In 2019, two distinct bacterial isolates were independently isolated from the fecal samples of separate dogs in Beijing, China. These cells exhibit microaerobic, are Gram-negative, motile, and possess a characteristic spiral shape with bipolar single flagellum. They display positive results for the oxidase test while being negative for both catalase and urease. These organisms measure approximately 0.2-0.3 µm in width and 4.5-6 µm in length. The colonies are wet, flat, grey, circular, and smooth with sizes ranging from 1 to 2 mm in diameter after 2 days of growth. However, strains may exhibit variations in size and morphology following extended incubation. Phylogenetic analyses based on the 16S rRNA gene and core genome indicated that these two isolates belong to the genus Helicobacter and formed a robust clade that was remains distinctly separate from currently recognized species. These two isolates shared low dDDH relatedness and ANI values with their closest species Helicobacter canis CCUG 32756T, with these values falling below the commonly cutoff values for strains of the same species. The genomic DNA G + C contents of strain XJK30-2 were 44.93 mol%. Comparing the phenotypic and phylogenetic features between these two isolates and their closely related species, XJK30-2 represents a novel species within the genus Helicobacter, for which the name Helicobacter zhangjianzhongii sp. nov. (Type strain XJK30-2T = GDMCC 1.3695T) is proposed.

Isolation and Genomic Characteristics of Cat-Borne Campylobacter felis sp. nov. and Sheep-Borne Campylobacter ovis sp. nov.

Nine novel bacterial strains were isolated from the feces of cats and sheep in 2019 and 2020 in Beijing, China. Cells were 1-3 µm long and ≤0.5 µm wide, Gram-stain negative, microaerobic, motile, oxidase positive, and urease negative. Phylogenetic analyses based on 16S rRNA gene sequences indicated that these nine isolates belong to the genus Campylobacter but formed two robust clades that were clearly separate from the currently recognized species and, respectively, isolated from the cat and sheep. Both these strains shared low 16S rRNA gene sequence similarity, dDDH relatedness, and ANI values with their closest species C. upsaliensis CCUG 14913T and C. lanienae NCTC 13004T, and against each other, which are below the cut-off values generally recognized for isolates of the same species. The genomic DNA G + C contents of type strains XJK22-1T and SYS25-1T were 34.99 mol% and 32.43 mol%, respectively. Electron microscopy showed that these cells were spiral shaped, with bipolar single flagella. Based on results from genotypic, phenotypic, phylogenetic, and phylogenomic analyses, these nine strains represent two novel species within the genus Campylobacter, for which the names Campylobacter felis sp. nov. (Type strain XJK22-1T = GDMCC 1.3684T = JCM 35847T) and Campylobacter ovis sp. nov. (Type strain SYS25-1T = GDMCC 1.3685T) are proposed.