Genomic and Phenotypic Analysis of bla KPC-2 Associated Carbapenem Resistance in Klebsiella aerogenes: Insights into Clonal Spread and Resistance Mechanisms Across Hospital Departments in Beijing.

Purpose: This study conducted an phenotypic and whole-genome sequencing analysis with Klebsiella aerogenes to elucidate its clinical epidemiological characteristics, antimicrobial resistance (AMR) phenotype, biofilm formation ability and hemolytic activity testing, AMR genes and phylogenetic relationships, so as to provide a further understanding of the intra-hospital strain transmission. Methods: Samples were collected from a hospital in Beijing between 2020 and 2022. All strains underwent bacterial identification, antimicrobial susceptibility testing (AST) using the VITEK-2 compact system. Biofilm formation ability and hemolytic activity were tested. Second-generation sequencing was applied to all strains, with those carrying the bla KPC gene were selected for third-generation sequencing. Whole-genome analysis identified resistance genes, plasmid types, MLST typing, and phylogenetic relationships. Plasmids were assembled to detect plasmid structures and AMR gene location. Results: Among the 42 K. aerogenes isolates, 21 were carbapenem-resistant K. aerogenes (CRKA). All strains exhibited strong biofilm formation and no hemolytic activity. Most were sourced from sputum (83.3%). CRKA demonstrated extensive resistance to antibiotics, particularly ß-lactamase inhibitors and Cefotetan. This resistance pattern was closely associated with the presence of an IncFII(pHN7A8) plasmid, which carried multiple resistance genes, including bla KPC-2, bla CTX-M-65, bla TEM-1, rmtB and a large number of mobile elements. The majority of CRKA strains clustered within the same branch of the phylogenetic tree, exhibiting minimal single nucleotide polymorphism (0-13 SNPs) differences, and they shared the same sequence type (ST292), resistance genes, and plasmids, originating from different departments, suggesting clonal transmission among the hospital. Conclusion: Our research reveals that the clonal transmission of CRKA occurs across various departments within the hospital. The widespread resistance observed in CRKA, attributed to the presence of bla KPC and ESBLs genes, underscores the need for heightened vigilance to prevent the further dissemination of CRKA within the hospital and, potentially, throughout the wider community.

Relevance of genetic causes and environmental adaptation of Cronobacter spp. isolated from infant and follow-up formula production factories and retailed products in China: A 7-year period of continuous surveillance based on genome-wide analysis.

The possible contamination routes, environmental adaptation, and genetic basis of Cronobacter spp. in infant and follow-up formula production factories and retailed products in mainland China have been determined by laboratory studies and whole-genome comparative analysis in a 7-year nationwide continuous surveillance spanning from 2012 to 2018. The 2-year continuous multicenter surveillance of the production process (conducted in 2013 and 2014) revealed that the source of Cronobacter spp. in the dry-blending process was the raw dry ingredients and manufacturing environment (particularly in the vibro sieve and vacuum cleaner), while in the combined process, the main contamination source was identified as the packing room. It is important to note that, according to the contamination control knowledge obtained from the production process surveillance, the contamination rate of retail powdered infant formula (PIF) and follow-up formula (FUF) products in China decreased significantly from 2016 onward, after improving the hygiene management practices in factories. The prevalence of Cronobacter spp. in retailed PIF and FUF in China in 2018 was dramatically reduced from 1.55 % (61/3925, in 2012) to an average as low as 0.17 % (13/7655 in 2018). Phenotype determination and genomic analysis were performed on a total of 90 Cronobacter spp. isolates obtained from the surveillance. Of the 90 isolates, only two showed resistance to either cefazolin or cefoxitin. The multilocus sequence typing results revealed that C. sakazakii sequence type 1 (ST1), ST37, and C. malonaticus ST7 were the dominant sequence types (STs) collected from the production factories, while C. sakazakii ST1, ST4, ST64, and ST8 were the main STs detected in the retailed PIF and FUF nationwide. One C. sakazakii ST4 isolate (1.1 %, 1/90) had strong biofilm-forming ability and 13 isolates (14.4 %, 13/90) had weak biofilm-forming ability. Genomic analysis revealed that Cronobacter spp. have a relatively stable core-genome and an increasing pan-genome size. Plasmid IncFIB (pCTU3) was prevalent in this genus and some contained 14 antibacterial biocide- and metal-resistance genes (BMRGs) including copper, silver, and arsenic resistant genes. Plasmid IncN_1 was predicted to contain 6 ARGs. This is the first time that a multi-drug resistance IncN_1 type plasmid has been reported in Cronobacter spp. Genomic variations with respect to BMRGs, virulence genes, antimicrobial resistance genes (ARGs), and genes involved in biofilm formation were observed among strains of this genus. There were apparent differences in copies of bcsG and flgJ between the biofilm-forming group and non-biofilm-forming group, indicating that these two genes play key roles in biofilm formation. The findings of this study have improved our understanding of the contamination characteristics and genetic basis of Cronobacter spp. in PIF and FUF and their production environment in China and provide important guidance to reduce contamination with this pathogen during the production of PIF and FUF.

Characterization of a Salmonella enterica serovar Typhimurium lineage with rough colony morphology and multidrug resistance.

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a major cause of salmonellosis, and the emergence of multidrug-resistant pathovariants has become a growing concern. Here, we investigate a distinct rough colony variant exhibiting a strong biofilm-forming ability isolated in China. Whole-genome sequencing on 2,212 Chinese isolates and 1,739 publicly available genomes reveals the population structure and evolutionary history of the rough colony variants. Characterized by macro, red, dry, and rough (mrdar) colonies, these variants demonstrate enhanced biofilm formation at 28 °C and 37 °C compared to typical rdar colonies. The mrdar variants exhibit extensive multidrug resistance, with significantly higher resistance to at least five classes of antimicrobial agents compared to non-mrdar variants. This resistance is primarily conferred by an IncHI2 plasmid harboring 19 antimicrobial resistance genes. Phylogenomic analysis divides the global collections into six lineages. The majority of mrdar variants belong to sublineage L6.5, which originated from Chinese smooth colony strains and possibly emerged circa 1977. Among the mrdar variants, upregulation of the csgDEFG operons is observed, probably due to a distinct point mutation (-44G > T) in the csgD gene promoter. Pangenome and genome-wide association analyses identify 87 specific accessory genes and 72 distinct single nucleotide polymorphisms associated with the mrdar morphotype.

Indirubin-3'-monoxime exhibits potent antiviral and anti-inflammatory effects against human adenoviruses in vitro and in vivo.

Human adenovirus (HAdV) infection is a major cause of respiratory disease, yet no antiviral drugs have been approved for its treatment. Herein, we evaluated the antiviral and anti-inflammatory effects of cyclin-dependent protein kinase (CDK) inhibitor indirubin-3'-monoxime (IM) against HAdV infection in cells and a transgenic mouse model. After evaluating its cytotoxicity, cytopathic effect reduction, antiviral replication kinetics, and viral yield reduction assays were performed to assess the anti-HAdV activity of IM. Quantitative real-time polymerase chain reaction (qPCR), quantitative reverse transcription PCR (qRT-PCR), and western blotting were used to assess the effects of IM on HAdV DNA replication, transcription, and protein expression, respectively. IM significantly inhibited HAdV DNA replication as well as E1A and Hexon transcription, in addition to significantly suppressing the phosphorylation of the RNA polymerase II C-terminal domain (CTD). IM mitigated body weight loss, reduced viral burden, and lung injury, decreasing cytokine and chemokine secretion to a greater extent than cidofovir. Altogether, IM inhibits HAdV replication by downregulating CTD phosphorylation to suppress viral infection and corresponding innate immune reactions as a promising therapeutic agent.

Genomic insights and antimicrobial resistance profiles of CRKP and non-CRKP isolates in a Beijing geriatric medical center: emphasizing the blaKPC-2 carrying high-risk clones and their spread.

Background: The escalating resistance of Klebsiella pneumoniae, a prevalent pathogen in healthcare settings, especially its carbapenem-resistant K. pneumoniae (CRKP), to a wide array of antibiotics, notably ß-lactams, constitutes a formidable challenge for healthcare and global public health management. Methods: This research compared the resistance phenotypes and genomic profiles of CRKP and Non-CRKP isolates in a Beijing hospital, focusing on high-risk blaKPC-2 gene-bearing CRKP clones and the structure of mobile genetic elements facilitating their spread across hospital departments. Forty K. pneumoniae isolates were collected from various departments of the hospital and subjected to antimicrobial susceptibility testing and whole-genome sequencing to analyze their resistance phenotypes and genomic features. Results: The study revealed that among the 31 CRKP isolates, ST11 is the most common sequence type, with K47 and OL101 being the dominant capsule types, primarily observed in the respiratory department. In terms of antimicrobial susceptibility: 87.5% of the isolates exhibited multidrug resistance (MDR), with a high resistance rate of 30% against tigecycline. All CRKP isolates demonstrated resistance to multiple drug classes (≥5 CLSI classes). Non-CRKP isolates also showed high resistance rates to minocycline and doxycycline (77.8%). the ST11-KL47-OL101 type emerged as the predominant clone among the CRKP isolates carrying the blaKPC-2 gene. This dominance appears to be mediated by the pKpnR03_2 plasmid, which harbors not only blaKPC-2 and rmtb but also gene clusters pertinent to iron transport and arsenic resistance. These isolates, clustering in the C3 clade of the phylogenetic tree, exhibited minor genetic variations and close evolutionary relationships, suggesting a plasmid-driven spread across various hospital departments. Conclusion: In summary, our study highlights the extensive spread of antibiotic-resistant K. pneumoniae across various departments in our hospital, with a particular emphasis on the dominant clonal proliferation of the ST11-KL47-OL101 CRKP strain. This finding underscores the significant role of plasmid-mediated gene transfer in the evolution and dissemination of resistant strains within hospital environments. The study emphasizes the necessity for ongoing surveillance of antibiotic resistance and genomic analysis in hospital settings to effectively monitor and manage these challenges.

Genetic characterization of a Salmonella enterica serovar Typhimurium isolated from an infant with concurrent resistance to ceftriaxone, ciprofloxacin and azithromycin.

OBJECTIVES: To investigate the resistance mechanism of a Salmonella Typhimurium (S. Typhimurium) isolated from a faecal sample of an infant, which exhibited concurrent resistance to ceftriaxone, ciprofloxacin and azithromycin. METHODS: Antimicrobial susceptibility testing was performed by broth microdilution in two kinds of drug-sensitive plates. Antimicrobial resistance (AMR) genes were identified by whole genome sequencing and bioinformatics analysis. Genotyping of the strain was performed by multilocus sequence typing (MLST). Plasmid DNA was sequenced and analysed using plasmid bioinformatics tools. RESULTS: The SH11G993 strain was resistant to 28 antibiotics and carried 54 AMR genes. MLST results showed that the strain belonged to a rare genotype. The plasmid profile and plasmid sequencing showed that the strain carried two resistance plasmids. The pSH11G993-1 carried 14 AMR genes (especially co-harboured blaCMY-2, mphA and ermB) and a variety of insertion sequences, belonging to the IncC. The pSH11G993-2 carried 3 AMR genes and 9 virulence genes, belonging to the IncFIB-FII, forming a novel resistance and virulence co-harbouring plasmid. CONCLUSIONS: Our findings highlight that continuously monitor the changes in antibiotic resistance patterns and research on the resistance mechanisms in potential human pathogens are imperative.

A novel humanized tri-receptor transgenic mouse model of HAdV infection and pathogenesis.

Human adenovirus (HAdV) is a highly virulent respiratory pathogen that poses clinical challenges in terms of diagnostics and treatment. Currently, no effective therapeutic drugs or prophylactic vaccines are available for HAdV infections. One factor contributing to this deficiency is that existing animal models, including wild-type and single-receptor transgenic mice, are unsuitable for HAdV proliferation and pathology testing. In this study, a tri-receptor transgenic mouse model expressing the three best-characterized human cellular receptors for HAdV (hCAR, hCD46, and hDSG2) was generated and validated via analysis of transgene insertion, receptor mRNA expression, and protein abundance distribution. Following HAdV-7 infection, the tri-receptor mice exhibited high transcription levels at the early and late stages of the HAdV gene, as well as viral protein expression. Furthermore, the tri-receptor mice infected with HAdV exhibited dysregulated cytokine responses and multiple tissue lesions. This transgenic mouse model represents human HAdV infection and pathogenesis with more accuracy than any other reported animal model. As such, this model facilitates the comprehensive investigation of HAdV pathogenesis as well as the evaluation of potential vaccines and therapeutic modalities for HAdV.

Resistance in Enteric Shigella and nontyphoidal Salmonella : emerging concepts.

PURPOSE OF REVIEW: The emergence of globally resistant enteric Shigella and nontyphoidal Salmonella strains (NTS) has limited the selection of effective drugs, which has become a major challenge for the treatment of infections. The purpose of this review is to provide the current opinion on the antimicrobial-resistant enteric Shigella and nontyphoidal Salmonella . RECENT FINDINGS: Enteric Shigella and NTS are resistant to almost all classes of antimicrobials in recent years. Those with co-resistance to ciprofloxacin, azithromycin and ceftriaxone, the first-line antibiotics for the treatment of infectious diarrhoea have emerged worldwide. Some of them have caused interregional and international spread by travel, trade, MSM, and polluted water sources. Several strains have even developed resistance to colistin, the last-resort antibiotic used for treatment of multidrug-resistant Gram-negative bacteria infections. SUMMARY: The drug resistance of enteric Shigella and NTS is largely driven by the use of antibiotics and horizontal gene transfer of mobile genetic elements. These two species show various drug resistance patterns in different regions and serotypes. Hence treatment decisions for Shigella and Salmonella infections need to take into consideration prevalent antimicrobial drug resistance patterns. It is worth noting that the resistance genes such as blaCTX,mph, ermB , qnr and mcr , which can cause resistance to ciprofloxacin, cephalosporin, azithromycin and colistin are widespread because of transmission by IncFII, IncI1, IncI2 and IncB/O/K/Z plasmids. Therefore, continuous global monitoring of resistance in Shigella and Salmonella is imperative.

Genetic characteristics of classical astroviruses in Shenzhen, China, 2016-2019.

Human astrovirus (HAstV) is a single-stranded, positive-sense RNA virus and is the leading cause of viral gastroenteritis. However, despite its prevalence, astroviruses still remain one of the least studied enteroviruses. In this study, we sequenced 11 classical astrovirus strains from clinical samples collected in Shenzhen, China from 2016 to 2019, analyzed their genetic characteristics, and deposited them into GenBank. We conducted phylogenetic analysis using IQ-TREE software, with references to astrovirus sequences worldwide. The phylogeographic analysis was performed using the Bayesian Evolutionary Analysis Sampling Trees program, through Bayesian Markov Chain Monte Carlo sampling. We also conducted recombination analysis with the Recombination Detection Program. The newly sequenced strains were categorized as HAstV genotype 1, which is the predominant genotype in Shenzhen. Phylogeographic reconstruction indicated that HAstV-1 may have migrated from the United States to China, followed by frequent transmission between China and Japan. The recombination analysis revealed recombination events within and across genotypes, and identified a recombination-prone region that produced relatively uniform recombination breakpoints and fragment lengths. The genetic analysis of HAstV strains in Shenzhen addresses the current lack of astrovirus data in the region of Shenzhen and provides key insights to the evolution and transmission of astroviruses worldwide. These findings highlight the importance of improving surveillance of astroviruses.

Successful clearance of persistent SARS-CoV-2 asymptomatic infection following a single dose of Ad5-nCoV vaccine.

Persistent asymptomatic (PA) SARS-CoV-2 infections have been identified. The immune responses in these patients are unclear, and the development of effective treatments for these patients is needed. Here, we report a cohort of 23 PA cases carrying viral RNA for up to 191 days. PA cases displayed low levels of inflammatory and interferon response, weak antibody response, diminished circulating follicular helper T cells (cTfh), and inadequate specific CD4+ and CD8+ T-cell responses during infection, which is distinct from symptomatic infections and resembling impaired immune activation. Administration of a single dose of Ad5-nCoV vaccine to 10 of these PA cases elicited rapid and robust antibody responses as well as coordinated B-cell and cTfh responses, resulting in successful viral clearance. Vaccine-induced antibodies were able to neutralize various variants of concern and persisted for over 6 months, indicating long-term protection. Therefore, our study provides an insight into the immune status of PA infections and highlights vaccination as a potential treatment for prolonged SARS-CoV-2 infections.

A Shigella sonnei clone with extensive drug resistance associated with waterborne outbreaks in China.

Antimicrobial resistance of Shigella sonnei has become a global concern. Here, we report a phylogenetic group of S. sonnei with extensive drug resistance, including a combination of multidrug resistance, coresistance to ceftriaxone and azithromycin (cefRaziR), reduced susceptibility to fluoroquinolones, and even colistin resistance (colR). This distinct clone caused six waterborne shigellosis outbreaks in China from 2015 to 2020. We collect 155 outbreak isolates and 152 sporadic isolates. The cefRaziR isolates, including outbreak strains, are mainly distributed in a distinct clade located in global Lineage III. The outbreak strains form a recently derived monophyletic group that may have emerged circa 2010. The cefRaziR and colR phenotypes are attributed to the acquisition of different plasmids, particularly the IncB/O/K/Z plasmid coharboring the blaCTX-M-14, mphA, aac(3)-IId, dfrA17, aadA5, and sul1 genes and the IncI2 plasmid with an mcr-1 gene. Genetic analyses identify 92 accessory genes and 60 single-nucleotide polymorphisms associated with the cefRaziR phenotype. Surveillance of this clone is required to determine its dissemination and threat to global public health.

Using a grey relational analysis in an improved Grunow-Finke assessment tool to detect unnatural epidemics.

The Grunow-Finke epidemiological assessment tool (GFT) has several limitations in its ability to differentiate between natural and man-made epidemics. Our study aimed to improve the GFT and analyze historical epidemics to validate the model. Using a gray relational analysis (GRA), we improved the GFT by revising the existing standards and adding five new standards. We then removed the artificial weights and final decision threshold. Finally, by using typically unnatural epidemic events as references, we used the GRA to calculate the unnatural probability and obtain assessment results. Using the advanced tool, we conducted retrospective and case analyses to test its performance. In the validation set of 13 historical epidemics, unnatural and natural epidemics were divided into two categories near the unnatural probability of 45%, showing evident differences (p < 0.01) and an assessment accuracy close to 100%. The unnatural probabilities of the Ebola virus disease of 2013 and Middle East Respiratory Syndrome of 2012 were 30.6% and 36.1%, respectively. Our advanced epidemic assessment tool improved the accuracy of the original GFT from approximately 55% to approximately 100% and reduced the impact of human factors on these outcomes effectively.

Highly sensitive and rapid detection of SARS-CoV-2 via a portable CRISPR-Cas13a-based lateral flow assay.

To rapidly identify individuals infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and control the spread of coronavirus disease (COVID-19), there is an urgent need for highly sensitive on-site virus detection methods. A clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (Cas)-based molecular diagnostic method was developed for this purpose. Here, a CRISPR system-mediated lateral flow assay (LFA) for SARS-CoV-2 was established based on multienzyme isothermal rapid amplification, CRISPR-Cas13a nuclease, and LFA. To improve the limit of detection (LoD), the crispr RNA, amplification primer, and probe were screened, in addition to concentrations of various components in the reaction system. The LoD of CRISPR detection was improved to 0.25 copy/µl in both fluorescence- and immunochromatography-based assays. To enhance the quality control of the CRISPR-based LFA method, glyceraldehyde-3-phosphate dehydrogenase was detected as a reference using a triple-line strip design in a lateral flow strip. In total, 52 COVID-19-positive and 101 COVID-19-negative clinical samples examined by reverse transcription polymerase chain reaction (RT-PCR) were tested using the CRISPR immunochromatographic detection technique. Results revealed 100% consistency, indicating the comparable effectiveness of our method to that of RT-PCR. In conclusion, this approach significantly improves the sensitivity and reliability of CRISPR-mediated LFA and provides a crucial tool for on-site detection of SARS-CoV-2.

An outbreak of acute respiratory disease caused by HAdV-55 in Beijing, China, 2020.

Human adenoviruses (HAdVs) can cause acute respiratory diseases (ARDs) worldwide, and HAdV-55 is a reemergent pathogen in recent years. In the study, we investigated an outbreak of ARD at a school due to HAdV-55 in Beijing, China, during the early outbreak of coronavirus disease 2019 (COVID-19). The epidemic prevention team was dispatched to the school to collect epidemiologic data and nasopharyngeal samples. Then, real-time reverse transcription polymerase chain reaction (PCR) and multiplex PCR assays were used to detect severe acute respiratory syndrome coronavirus 2 and other respiratory pathogens, respectively. One representative HAdV-55 isolate was selected and submitted for whole-genome sequencing using a MiSeq system and the whole-genome phylogenetic tree was conducted based on the maximum likelihood method. The outbreak lasted from January 27 to February 6, 2020, and 108 students developed fever, among whom 60 (55.56%) cases were diagnosed with HAdV-55 infection in the laboratory using real-time PCR and 56 cases were hospitalized. All the confirmed cases had a fever and 11 cases (18.33%) presented with a fever above 39°C. Other main clinical symptoms included sore throat (43.33%) and headache (43.33%). We obtained and assembled the full genome of one isolate, BJ-446, with 34 761 nucleotides in length. HAdV-55 isolate BJ-446 was 99.85% identical to strain QS-DLL, which was the first HAdV-55 strain in China isolated from an ARD outbreak in Shanxi in 2006. One and four amino acid mutations were observed in the hexon gene and the coding region of L2 pV 40.1 kDa protein, respectively. We identified the first HAdV-55 infection associated with the ARD outbreak in Beijing since the emergence of COVID-19. The study suggests that improved surveillance of HAdV is needed, although COVID-19 is still prevalent in the world.

Quantitative analysis of the impact of various urban socioeconomic indicators on search-engine-based estimation of COVID-19 prevalence.

Numerous studies have proposed search engine-based estimation of COVID-19 prevalence during the COVID-19 pandemic; however, their estimation models do not consider the impact of various urban socioeconomic indicators (USIs). This study quantitatively analysed the impact of various USIs on search engine-based estimation of COVID-19 prevalence using 15 USIs (including total population, gross regional product (GRP), and population density) from 369 cities in China. The results suggested that 13 USIs affected either the correlation (SC-corr) or time lag (SC-lag) between search engine query volume and new COVID-19 cases ( p <0.05). Total population and GRP impacted SC-corr considerably, with their correlation coefficients r for SC-corr being 0.65 and 0.59, respectively. Total population, GRP per capita, and proportion of the population with a high school diploma or higher had simultaneous positive impacts on SC-corr and SC-lag ( p <0.05); these three indicators explained 37-50% of the total variation in SC-corr and SC-lag. Estimations for different urban agglomerations revealed that the goodness of fit, R 2 , for search engine-based estimation was more than 0.6 only when total urban population, GRP per capita, and proportion of the population with a high school diploma or higher exceeded 11.08 million, 120,700, and 38.13%, respectively. A greater urban size indicated higher accuracy of search engine-based estimation of COVID-19 prevalence. Therefore, the accuracy and time lag for search engine-based estimation of infectious disease prevalence can be improved only when the total urban population, GRP per capita, and proportion of the population with a high school diploma or higher are greater than the aforementioned thresholds.

Dissemination of blaNDM-5 in Escherichia coli through the IncX3 Plasmid from Different Regions in China.

The spread of NDM-5-producing Escherichia coli has become a severe challenge in clinical therapy, which necessitates reliable detection and surveillance methods. However, limited information is available regarding the prevalence and dissemination of the blaNDM-5 gene in E. coli in China. Therefore, we investigated the dissemination of the blaNDM-5 gene in carbapenem-resistant E. coli isolates from different regions. A total of 1,180 carbapenem-resistant enterobacteriaceae strains were obtained from patients admitted to the 20 sentinel hospitals in 8 cities. Strains positive for blaNDM-5 were detected using the Vitek 2 compact system, 16S ribosomal RNA (rRNA) gene sequencing, polymerase chain reaction, the S1 pulsed-field gel electrophoresis assay, and Southern blot hybridization. The horizontal-transfer capability of the blaNDM gene was assessed by filter mating with a standard E. coli J53 azide-resistant strain as the recipient. Genotyping, susceptibility testing, and whole genome sequencing were performed. Seven strains of blaNDM-5-positive E. coli were detected in 1,180 clinical strains from different regions in China. The blaNDM-5-carrying strains showed resistance to multiple tested antibiotics and belonged to two widespread sequence types, sequence type (ST)167 and ST405. Antimicrobial resistance genes, including blaCTX-M, blaOXA, blaCMY, and two novel blaTEM variants (blaTEM-230 and blaTEM-231) were also identified. Southern blotting located the blaNDM-5 gene on 46 kb IncX3 plasmids in all isolates, which showed only two single nucleotide differences between EJN003 and the other strains. This study further confirms the increasing occurrence of blaNDM-5-carrying IncX3 plasmids and the dissemination of carbapenem resistance in E. coli isolates using the plasmid from different parts in China, which warrants stringent surveillance and control measures.

Rapid Identification and Source Tracing of a Salmonella Typhimurium Outbreak in China by Metagenomic and Whole-Genome Sequencing.

Salmonella spp. are among the most prevalent foodborne pathogens. Rapid identification of etiologic agents during foodborne outbreaks is of great importance. In this study, we report a traceback investigation of a Salmonella outbreak in China. Metagenomic sequencing of suspected food samples was performed on MinION and MiSeq platforms. Real-time nanopore sequencing analysis identified reads belonging to the Enterobacteriaceae family. MiSeq sequencing identified 63 reads specifically mapped to Salmonella. Conventional methods including quantitative-PCR and culture-based isolation confirmed as Salmonella enterica serovar Typhimurium. The foodborne outbreak of Salmonella Typhimurium was further recognized by whole-genome sequencing and pulsed-field gel electrophoresis analysis. Our study demonstrates the ability of metagenomic sequencing to rapidly identify enteric pathogens directly from food samples. These results highlight the capacity of metagenomic sequencing to deliver actionable information rapidly and to expedite the tracing and identification of etiologic agents during foodborne outbreaks.

Effectiveness of BNT162b2 and mRNA-1273 Vaccines against COVID-19 Infection: A Meta-Analysis of Test-Negative Design Studies.

Although numerous COVID-19 vaccines are effective against COVID-19 infection and variants of concern (VOC) in the real world, it is imperative to obtain evidence of the corresponding vaccine effectiveness (VE). This study estimates the real-world effectiveness of the BNT162b2 and mRNA-1273 vaccines against COVID-19 infection and determines the influence of different virus variants on VE by using test-negative design (TND) studies. We systematically searched for published articles on the efficacy of BNT162b2 and mRNA-1273 against COVID-19 infection. Two researchers independently selected and extracted data from eligible studies. We calculated the VE associated with different vaccine types, SARS-CoV-2 variants, and vaccination statuses, using an inverse variance random-effects model. We selected 19 eligible studies in the meta-analysis from 1651 records. For the partially vaccinated group, the VE of BNT162b2 and mRNA-1273 was 61% and 78% against COVID-19 infection, respectively. For the completely vaccinated group, the VE of BNT162b2 and mRNA-1273 was 90% and 92% against COVID-19 infection, respectively. During subgroup analyses, the overall VE of BNT162b2 and mRNA-1273 against the Delta variant was 53% and 71%, respectively, for the partially vaccinated group; the respective VE values were 85% and 91% for the fully vaccinated group. Irrespective of the BNT162b2 or mRNA-1273 vaccines, the Delta variant significantly weakened vaccine protection for the partially vaccinated group, while full vaccination was highly effective against COVID-19 infection and various VOC. The mRNA-1273 vaccine is more effective against COVID-19 infection and VOC than the BNT162b2 vaccine, especially for the partially vaccinated group. Overall, the results provide recommendations for national and regional vaccine policies.

Corrigendum: A Severe Gastroenteritis Outbreak of Salmonella enterica Serovar Enteritidis Linked to Contaminated Egg Fried Rice, China, 2021.

[This corrects the article DOI: 10.3389/fmicb.2021.779749.].