Antimicrobial resistance and population genomics of emerging multidrug-resistant 4,[5],12:i:- in Guangdong, China.

4,[5],12:i:-, a monophasic variant of Typhimurium, has emerged as a global cause of multidrug-resistant salmonellosis and has become endemic in many developing and developed countries, especially in China. Here, we have sequenced 352 clinical isolates in Guangdong, China, during 2009-2019 and performed a large-scale collection of 4,[5],12:i:- with whole genome sequencing (WGS) data across the globe, to better understand the population structure, antimicrobial resistance (AMR) genomic characterization, and transmission routes of 4,[5],12:i:- across Guangdong. 4,[5],12:i:- strains showed broad genetic diversity; Guangdong isolates were found to be widely distributed among the global lineages.

Carriage and Transmission of in Salmonella Typhimurium and Its Monophasic 1,4,[5],12:i:- Variants from Diarrheal Outpatients: a 10-Year Genomic Epidemiology in Guangdong, Southern China.

The banning of colistin as a feed additive for food-producing animals in mainland China in 2017 caused the decline in the prevalence of Escherichia coli-mobilized colistin resistance () in China. Salmonella Typhimurium and its monophasic 1,4,[5],12:i:- variants are also the main species associated with the spread of ; however, the evidence of the prevalence and transmission of among Salmonella is lacking. Herein, the 5,354 Salmonella isolates recovered from fecal samples of diarrheal patients in Guangdong, Southern China, from 2009 to 2019 were screened for colistin resistance and , and -positive isolates were characterized based on whole-genome sequencing (WGS) data.

Phylogenomic analysis of Salmonella Indiana ST17, an emerging MDR clonal group in China.

Objectives: To reconstruct the genomic epidemiology and evolution of MDR Salmonella Indiana in China.

Methods: A total of 108 Salmonella Indiana strains were collected from humans and livestock in China. All isolates were subjected to WGS and antimicrobial susceptibility testing.

Kinetic Characteristics of Neutralizing Antibody Responses Vary among Patients with COVID-19.

Objective: The coronavirus disease 2019 (COVID-19) pandemic continues to present a major challenge to public health. Vaccine development requires an understanding of the kinetics of neutralizing antibody (NAb) responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Methods: In total, 605 serum samples from 125 COVID-19 patients (from January 1 to March 14, 2020) varying in age, sex, severity of symptoms, and presence of underlying diseases were collected, and antibody titers were measured using a micro-neutralization assay with wild-type SARS-CoV-2.

Global clonal spread of mcr-3-carrying MDR ST34 Salmonella enterica serotype Typhimurium and monophasic 1,4,[5],12:i:- variants from clinical isolates.

Objectives: To investigate the prevalence and transmission of mcr-3 among Salmonella enterica serotype Typhimurium and 1,4,[5],12:i:-.

Methods: A total of 4724 clinical Salmonella isolates were screened for the presence of mcr-3 in China during 2014-19. The clonal relationship of the mcr-3-positive isolates and their plasmid contents and complete sequence were also characterized based on WGS data from the Illumina and MinION platforms.

Deficiency in mitochondrial complex I activity due to Ndufs6 gene trap insertion induces renal disease.

Aims: Defects in the activity of enzyme complexes of the mitochondrial respiratory chain are thought to be responsible for several disorders, including renal impairment. Gene mutations that result in complex I deficiency are the most common oxidative phosphorylation disorders in humans. To determine whether an abnormality in mitochondrial complex I per se is associated with development of renal disease, mice with a knockdown of the complex I gene, Ndufs6 were studied.

[Surveillance and analysis on the pathogenic features of Salmonella in Guangdong province in 2010].

Objective: In order to better understand the nature of Salmonella infection in diarrheal patients in Guangdong province, the study analyzed the serum types, antibiotic resistance and molecular determinants of the isolated Salmonella strains.

Methods: In year 2010, 8405 diarrhea patients from 16 surveillant hospital in Guangzhou, Zhongshan, Dongguan, Zhuhai, Maoming, Yangjiang and Jiangmen cities in Guangdong province, were recruited in the study. A total of 8405 fecal specimen were collected and subjected to Salmonella isolation and culture.

Tissue-specific splicing of an Ndufs6 gene-trap insertion generates a mitochondrial complex I deficiency-specific cardiomyopathy.

Mitochondrial complex I (CI) deficiency is the most common mitochondrial enzyme defect in humans. Treatment of mitochondrial disorders is currently inadequate, emphasizing the need for experimental models. In humans, mutations in the NDUFS6 gene, encoding a CI subunit, cause severe CI deficiency and neonatal death.

[Automated ribotyping of Salmonella and Staphylococcus aureus in food poisoning of Guangdong province].

Objective: To understand the genetic polymorphism of Salmonella and Staphylococcus aureus in Guangdong province, as well as to explore methods for identifying and tracing the source of these two foodborne pathogens.

Methods: Using the automated ribotyping system, two foodborne pathogens were tested with either EcoR I or Pvu II restriction enzymes. BioNumerics software was then applied for image analysis, database establishment and other corresponding analysis.

[Comparative study on the phenotypic characteristics and molecular typing of foodborne Vibrio parahaemolyticus in Guangdong province].

Objective: To understand the phenotypic characteristics of foodborne Vibrio parahaemolyticus in Guangdong province through carrying out a comprehensive comparison including pulse field gel electrophoresis, ribotyping and serotyping.

Methods: 74 different Vibrio parahaemolyticus strains isolated from seafood and cases due to food poisoning in Guangdong province were under serotyping and susceptibility testing, in addition to the testing of direct heat hemolysin (tdh) and the heat hemolysin-related hemolysin hormone (trh) via PCR. Ribosomal genotyping (ribotyping) with EcoR I restriction enzyme was utilized on 74 different Vibrio parahaemolyticus isolates, whereas pulsed-field gel electrophoresis (PFGE) with the Not I restriction enzyme was used on 74 different Vibrio parahaemolyticus isolates.

[Surveillance program on and the distribution related to the virulence-associated genes of Vibrio cholerae in estuary of Pearl River].

Objective: To understand the distribution, molecular characteristics and virulence genes of the O1 and O139 Vibrio cholerae isolates from the Pearl River Estuary water.

Methods: Vibrio cholerae isolates collected from the Pearl River estuary waters from January 2009 to December 2010, were tested by PCR for eight virulence-related genes, including cholera toxin (ctxA), zonula occludens toxin (zot), accessory cholera enterotoxin (ace), hemolysin (hlyA), toxin-coregulated pilus (tcpA), outer membrane protein (ompU), and the regulatory protein genes (tcpI, toxR). Genetic relation was assessed by pulsed-field gel electrophoresis (PFGE) and the patterns were clustered by BioNumerics.

[Etiologic characteristics of Vibrio parahaemolyticus strains causing outbreaks and sporadic cases in Guangdong, 2009].

Objective: To study the serotypes, virulence features and molecular characteristics of Vibrio parahaemolyticus isolated in food poisoning cases and surveillance program on diarrhea patients in Guangdong, 2009.

Methods: 95 Vibrio parahaemolyticus strains from food poisoning cases and 15 strains from surveillance program on diarrhea patients were serotyped and detected for tdh (thermostable direct hemolysin, tdh) and trh (tdh-related hemolysin gene, trh) by PCR. 81 sero-variant Vibrio parahaemolyticus strains were selected through PFGE subtyping.

[Etiologic detection and epidemiological analysis of one suspected case of diphtheria in Guangdong province].

Objective: To clarify the diagnosis of one suspected case of diphtheria in Guangdong province by epidemiological analysis and etiologic detection.

Methods: On July 6th 2010, the corynebacterium diphtheria was detected from the nasal secretions of one nasopharyngeal carcinoma patient in a college-town hospital in Guangzhou City, Guangdong Province. The patient and the close contacts were asked to participate in the epidemiological survey; and their nasopharyngeal swabs (3 samples) and the nasal secretions of the patient (1 sample) were collected.

[Surveillance on Salmonella infection in Guangdong province, 2008 - 2009].

Objective: To understand the infection of Salmonella (S.) in patients with diarrhea and outbreaks caused by Salmonella to identify the serotypes, resistance to antibiotics and PFGE types of the strains from the surveillance program in Guangdong province.

Methods: S.

Respiratory chain complex I deficiency caused by mitochondrial DNA mutations.

Defects of the mitochondrial respiratory chain are associated with a diverse spectrum of clinical phenotypes, and may be caused by mutations in either the nuclear or the mitochondrial genome (mitochondrial DNA (mtDNA)). Isolated complex I deficiency is the most common enzyme defect in mitochondrial disorders, particularly in children in whom family history is often consistent with sporadic or autosomal recessive inheritance, implicating a nuclear genetic cause. In contrast, although a number of recurrent, pathogenic mtDNA mutations have been described, historically, these have been perceived as rare causes of paediatric complex I deficiency.

[Development of a DNA microarray for detecting 8 common species of food-borne bacterial pathogens in south China].

Objective: To prepare a DNA Microarray that can detect 8 common species of food borne bacterial pathogens in south China.

Methods: All the 70mer oligo probes were designed on the characteristic genome loci of the 8 species of food borne bacterial pathogens. Eight subarrays corresponding to the 8 food borne bacterial pathogens were spotted onto the slide and integrated into a pan-array on the chip.

Phenotypic and genotypic characterization Vibrio cholerae O139 of clinical and aquatic isolates in China.

To enhance the understanding of epidemiological impact of environmental Vibrio cholerae O139 strains, we characterized 10 clinical and 20 environmental isolates collected from human clinical samples and Pear River estuary during 2006 to 2008. Isolates were tested by PCR for eight virulence genes: cholera toxin (ctxA), zonula occludens toxin (zot), accessory cholera enterotoxin (ace), hemolysin (hlyA), NAG-specific heat-stable toxin (st), toxin-coregulated pilus (tcpA), outer membrane protein (ompU), and regulatory protein genes (tcpI). Genetic relatedness was assessed by pulsed-field gel electrophoresis (PFGE), and antibiotic susceptibility was determined using disk diffusion.

[Molecular characters of epidemic cerebrospinal W135 Neisseria meningitidis strain firstly isolated in Guangdong province].

Objective: To analyze the molecular characters of the W135 Neisseria meningitidis strain firstly isolated from patients in Guangdong province.

Methods: Biochemical profile by using the API NH system (bio-Merieux, France) was used for confirmation,and sero-grouping of the meningococcal isolates including one serogroup W135, one serogroup C and three serogroups of a Neisseria meningitidis isolated from patients in Guangdong province in recent two years were performed. The subtype was determined after amplifying porA and porB respectively from the genome DNA of Neisseria meningitidis.

[Surveillance and pathogenic analysis on non-typhoidal Salmonella in Guangdong province, 2007].

Objective: To understand non-typhoid Salmonella in diarrhea patients from Guangdong province in order to timely discover the outbreaks caused by them as well as to grasp the serotypes, antibiotic resistance and pulse-field gel electrophoresis (PFGE) types of those strains isolated from this surveillance program.

Methods: Salmonella strains from diarrhea patients were detected and all the positive strains were tested by serum agglutination, antibiotic susceptibility and PFGE.

Results: 71 non-typhoid Salmonella strains were isolated from 1128 stool samples, with a positive rate of 6.