Pyrethroids exposure alters the community and function of the internal microbiota in Aedes albopictus.

Large amounts of insecticides bring selection pressure and then develop insecticide resistance in Aedes albopictus. This study demonstrated for the first time the effect of pyrethroid exposure on the internal microbiota in Ae. albopictus. 36, 48, 57 strains of virgin adult Ae. albopictus were exposed to the pyrethroids deltamethrin (Dme group), ß-cypermethrin (Bcy group), and cis-permethrin (Cper group), respectively, with n-hexane exposure (Hex group) as the controls (n = 36). The internal microbiota community and functions were analyzed based on the metagenomic analysis. The analysis of similarity (ANOSIM) results showed that the Hex/Bcy (p = 0.001), Hex/Cper (p = 0.006), Hex/Dme (p = 0.001) groups were well separated, and the internal microbes of Ae. albopictus vary in the composition and functions depending on the type of pyrethroid insecticide they are applied. Four short chain fatty acid-producing genera, Butyricimonas, Prevotellaceae, Anaerococcus, Pseudorhodobacter were specifically absent in the pyrethroid-exposed mosquitoes. Morganella and Streptomyces were significantly enriched in cis-permethrin-exposed mosquitoes. Wolbachia and Chryseobacterium showed significant enrichment in ß-cypermethrin-exposed mosquitoes. Pseudomonas was significantly abundant in deltamethrin-exposed mosquitoes. The significant proliferation of these bacteria may be closely related to insecticide metabolism. Our study recapitulated a specifically enhanced metabolic networks relevant to the exposure to cis-permethrin and ß-cypermethrin, respectively. Benzaldehyde dehydrogenase (EC 1.2.1.28), key enzyme in aromatic compounds metabolism, was detected enhanced in cis-permethrin and ß-cypermethrin exposed mosquitoes. The internal microbiota metabolism of aromatic compounds may be important influencing factors for pyrethroid resistance. Future work will be needed to elucidate the specific mechanisms by which mosquito microbiota influences host resistance and vector ability.

Hemorrhagic fever with renal syndrome caused by destruction of residential area of rodent in a construction site: epidemiological investigation.

BACKGROUND: An outbreak of hemorrhagic fever with renal syndrome (HFRS), caused by a Hantavirus, affected nine adult males in the southwest area of Xi'an in November 2020 was analyzed in this study. METHODS: Clinical and epidemiological data of HFRS patients in this outbreak were retrospectively analyzed. The whole genome of a hantavirus named 201120HV03xa (hv03xa for short) isolated from Apodemus agrarius captured in the construction site was sequenced and analyzed. In addition, nine HFRS patients were monitored for the IgG antibody against the HV N protein at 6 and 12 months, respectively. RESULTS: In this study, inhalation of aerosolized excreta and contaminated food may be the main source of infection. Genome analysis and phylogenetic analysis showed that hv03xa is a reassortment strain of HTNV, having an S segment related to A16 of HTN 4, an M segment related to Q37 and Q10 of HTN 4, and an L segment related to prototype strain 76-118 of HTN 7. Potential recombination was detected in the S segment of hv03xa strain. The anti-HV-IgG level of all the patients persist for at least one year after infection. CONCLUSIONS: This report documented an HFRS outbreak in Xi'an, China, which provided the basic data for epidemiological surveillance of endemic HTNV infection and facilitated to predict disease risk and implement prevention measures.

Serum IP-10 and IL-7 levels are associated with disease severity of coronavirus disease 2019.

We quantified the serum levels of 34 cytokines/chemokines in 30 patients with SARS-CoV-2 infection. Elevated levels of IP-10 and IL-7 were detected in the acute and convalescent stages of the infection and were highly associated with disease severity.

Transmission Potential of Asymptomatic and Paucisymptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infections: A 3-Family Cluster Study in China.

Data concerning the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in asymptomatic and paucisymptomatic patients are lacking. We report a 3-family cluster of infections involving asymptomatic and paucisymptomatic transmission. Eight of 15 (53%) members from 3 families were confirmed with SARS-CoV-2 infection. Of 8 patients, 3 were asymptomatic and 1 was paucisymptomatic. An asymptomatic mother transmitted the virus to her son, and a paucisymptomatic father transmitted the virus to his 3-month-old daughter. SARS-CoV-2 was detected in the environment of 1 household. The complete genomes of SARS-CoV-2 from the patients were > 99.9% identical and were clustered with other SARS-CoV-2 sequences reported from China and other countries.

Endogenous ethanol produced by intestinal bacteria induces mitochondrial dysfunction in non-alcoholic fatty liver disease.

BACKGROUND AND AIM: A causal relationship between changes of the gut microbiome and non-alcoholic fatty liver disease (NAFLD) remains unclear. We demonstrated that endogenous ethanol (EnEth) produced by intestinal microbiota is likely a causative agent of NAFLD. METHODS: Two mutants with different alcohol-producing abilities, namely, W14-adh and W14Δadh, were constructed using the clinical high alcohol-producing (HiAlc) Klebsiella pneumoniae strain W14 as a parent. Damage to hepatocytes caused by bacteria with different alcohol-producing capacities was evaluated (EtOH group as positive control). The ultrastructural changes of mitochondria were assessed via transmission electron microscopy (TEM). Hepatic levels of mitochondrial reactive oxygen species (ROS), DNA damage, and adenosine triphosphate were examined. RESULTS: The results illustrated that steatosis was most severe in the W14-adh group, followed by the W14 group, whereas the W14Δadh group had few fatty droplets. TEM and examination of related protein expression revealed that the mitochondrial integrity of HepG2 hepatocytes was considerably damaged in the EtOH and bacteria treatment groups. The impaired mitochondrial function in HepG2 hepatocytes was evidenced by reduced adenosine triphosphate content and increased mitochondrial ROS accumulation and DNA damage in the EtOH and bacteria treatment groups, especially the W14-adh group. Meanwhile, liver injury and mitochondrial damage were observed in the hepatocytes of mice. The livers of mice in the W14-adh group, which had the highest ethanol production, exhibited the most serious damage, similar to that in the EtOH group. CONCLUSIONS: EnEth produced by HiAlc bacteria induces mitochondrial dysfunction in NAFLD.

Identification and molecular characterization of Serratia marcescens phages vB_SmaA_2050H1 and vB_SmaM_2050HW.

Serratia marcescens is a rod-shaped, Gram-negative bacterium causing nosocomially acquired infections. Bacteriophages are natural opponents of their pathogenic bacterial hosts and could be an alternative to traditional antibiotic treatments. In this study, two S. marcescens-specific bacteriophages, vB_SmaA_2050H1 and vB_SmaM_2050HW, were isolated from two different waste samples in China. Phage plaque assays, transmission electron microscopy, host-range determination, and one-step growth curve analyses were performed for both phages. vB_SmaA_2050H1 was classified as belonging to the family Ackermannviridae, and vB_SmaM_2050HW was classified as belonging to the family Myoviridae. One-step growth curve analysis showed that the latent and rise period of vB_SmaA_2050H1 were 80 min and 50 min, respectively, with a burst size of approximately 103 phage particles per infected cell. For vB_SmaM_2050HW, latent and rise periods of 40 min and 60 min, respectively, were determined, with a burst size of approximately 110 phage particles per infected cell. vB_SmaA_2050H1 infected 10 of the 15 (66.67%) S. marcescens strains tested, while vB_SmaM_2050HW infected 12 (80%) of the strains. Whole-genome sequencing and annotation of each of the phage genomes revealed genome sizes of 159,631 bp and 276,025 bp for vB_SmaA_2050H1 and vB_SmaM_2050HW, respectively, with the respective genomes containing 213 and 363 putative open reading frames. Sequence analysis of the genomes revealed that vB_SmaA_2050H1 is a member of the ViI-like family, while vB_SmaM_2050HW is a novel virulent bacteriophage. These findings provide further insights into the genomic structures of S. marcescens bacteriophages.

Characterization of phiCFP-1, a virulent bacteriophage specific for Citrobacter freundii.

Citrobacter freundii, a Gram-negative bacterium, causes many opportunistic infections. Bacteriophage phiCFP-1 was isolated and characterized by its ability to lyse the multidrug-resistant clinical C. freundii strain P10159. Transmission electron microscopy showed that the phage has an icosahedral head and a short tail, making it a Podoviridae family member. In a single-step growth experiment, phiCFP-1 exhibited an eclipse period of 20 min and a burst size of 100 particles per cell. Its genome assembled as a circular molecule when genomic sequencing was completed. However, based on genome content and organization, it was categorized as a classic T7-related phage, and such phages are known to have linear genomes with direct terminal repeats. With the quick and simple method established herein, the 38,625-bp linear double-stranded DNA with 229-bp direct terminal repeats was accurately identified. The genome contained 43 putative open reading frames and no tRNA genes. Using a proteomics-based approach, seven viral and two host proteins from purified phiCFP-1 particles were identified. Comparative genomics and recombination analyzes revealed close genetic relatedness among phiCFP-1, phiYeO3-12/vB_YenP_AP5 (from Yersinia enterocolitica O3), and phiSG-JL2 (from Salmonella enterica).

Cirrhosis related functionality characteristic of the fecal microbiota as revealed by a metaproteomic approach.

BACKGROUND: Intestinal microbiota operated as a whole and was closely related with human health. Previous studies had suggested close relationship between liver cirrhosis (LC) and gut microbiota. METHODS: To determine the functional characteristic of the intestinal microbiota specific for liver cirrhosis, the fecal metaproteome of three LC patients with Child-Turcotte-Pugh (CTP) score of A, B, and C, and their spouse were first compared using high-throughput approach based on denaturing polyacrylamide gel electrophoresis and liquid chromatography-tandem mass spectrometry in our study. RESULTS: A total of 5,020 proteins (88 % from bacteria, 12 % form human) were identified and annotated based on the GO and KEGG classification. Our results indicated that the LC patients possessed a core metaproteome including 119 proteins, among which 14 proteins were enhanced expressed and 7 proteins were unique for LC patients compared with the normal, which were dominant at the function of carbohydrate metabolism. In addition, LC patients have unique biosynthesis of branched chain amino acid (BCAA), pantothenate, and CoA, enhanced as CTP scores increased. Those three substances were all important in a wide array of key and essential biological roles of life. CONCLUSIONS: We observed a highly comparable cirrhosis-specific metaproteome clustering of fecal microbiota and provided the first supportive evidence for the presence of a LC-related substantial functional core mainly involved in carbohydrate, BCAA, pantothenate, and CoA metabolism, suggesting the compensation of intestinal microbiota for the fragile and innutritious body of cirrhotic patients.

Bacteriophages of Yersinia pestis.

Bacteriophage play many varied roles in microbial ecology and evolution. This chapter collates a vast body of knowledge and expertise on Yersinia pestis phages, including the history of their isolation and classical methods for their isolation and identification. The genomic diversity of Y. pestis phage and bacteriophage islands in the Y. pestis genome are also discussed because all phage research represents a branch of genetics. In addition, our knowledge of the receptors that are recognized by Y. pestis phage, advances in phage therapy for Y. pestis infections, the application of phage in the detection of Y. pestis, and clustered regularly interspaced short palindromic repeats (CRISPRs) sequences of Y. pestis from prophage DNA are all reviewed here.

A novel New Delhi metallo-ß-lactamase variant, NDM-14, isolated in a Chinese Hospital possesses increased enzymatic activity against carbapenems.

A novel New Delhi metallo-ß-lactamase (NDM) variant, NDM-14, was identified in clinical isolate Acinetobacter lwoffii JN49-1, which was recovered from an intensive care unit patient at a local hospital in China. NDM-14, which differs from other existing enzymes by an amino acid substitution at position 130 (Asp130Gly), possesses enzymatic activity toward carbapenems that is greater than that of NDM-1. Kinetic data indicate that NDM-14 has a higher affinity for imipenem and meropenem.

Open-source genomic analysis of Shiga-toxin-producing E. coli O104:H4.

An outbreak caused by Shiga-toxin­producing Escherichia coli O104:H4 occurred in Germany in May and June of 2011, with more than 3000 persons infected. Here, we report a cluster of cases associated with a single family and describe an open-source genomic analysis of an isolate from one member of the family. This analysis involved the use of rapid, bench-top DNA sequencing technology, open-source data release, and prompt crowd-sourced analyses. In less than a week, these studies revealed that the outbreak strain belonged to an enteroaggregative E. coli lineage that had acquired genes for Shiga toxin 2 and for antibiotic resistance.

Outer membrane proteins ail and OmpF of Yersinia pestis are involved in the adsorption of T7-related bacteriophage Yep-phi.

Yep-phi is a T7-related bacteriophage specific to Yersinia pestis, and it is routinely used in the identification of Y. pestis in China. Yep-phi infects Y. pestis grown at both 20°C and 37°C. It is inactive in other Yersinia species irrespective of the growth temperature. Based on phage adsorption, phage plaque formation, affinity chromatography, and Western blot assays, the outer membrane proteins of Y. pestis Ail and OmpF were identified to be involved, in addition to the rough lipopolysaccharide, in the adsorption of Yep-phi. The phage tail fiber protein specifically interacts with Ail and OmpF proteins, and residues 518N, 519N, and 523S of the phage tail fiber protein are essential for the interaction with OmpF, whereas residues 518N, 519N, 522C, and 523S are essential for the interaction with Ail. This is the first report to demonstrate that membrane-bound proteins are involved in the adsorption of a T7-related bacteriophage. The observations highlight the importance of the tail fiber protein in the evolution and function of various complex phage systems and provide insights into phage-bacterium interactions.

[Fitness costs of blaNDM-1 bearing plasmid pNDM-BJ01 in Acinetobacter lwoffii].

OBJECTIVE: To investigate the fitness costs of the New Delhi Metallo-beta-lactamase-1 (bIaNDM-1) bearing plasmid pNDM-BJ01 in Acinetobacter lwoffii strain 10621, and to evaluate the potentials of the sustainahility and expansions among the Acinetobacter lwoffii population. METHODS: We obtained the spontaneous mutant of A. lwoffii missing pNDM-BJ01 10621NDM-1(-) via serial passages of the wild strain 10621NDM1(-) on the antibiotics-free media. We then compared the in vitro fitness of these two strains by measuring the growth curves, the ability of biofilm formation and the survival rates in nutrient-free PBS buffer. RESULTS: Plasmid pNDM-BJ01 was unstable in A. lwoffii strain 10621, and 11 passages will be enough to get it deleted from the ancestral strain. We found no significant difference in the growth curves either at 26 or 37 degrees C for 10621NDM-1(+) and 10621NDM-1(-). The biofilm formation ability of the plasmid free derivate 10621NDM-1(-) was significant higher than its resistant ancestor 10621NDM-1(+) at 26 degrees C, whereas the latter showed higher ability of biofilm formation at 37 degrees C. Strain 10621NDM-1(+) was vulnerable in the nutrient-free PBS buffer, with less than 5% survival rate on the first day and dying out on the sixth day, whereas 10621NDM-1(-) survived till the seventh day. CONCLUSION: blaNDM-1 bearing plasmid pNDM-BJ01 possesses significant fitness costs in A. lwoffii strain 10621, and it will get depleted easily if the antibiotic press released. pNDM-BJ01-free 10621NDM-1(-) strain has higher fitness than its ancestor, 10621NDM-1(+), which implies the limited expansion potential of plasmid pNDM-BJ01 in A. lwoffii.

Sensitive and rapid detection of Culex pipiens and Aedes albopictus.

Background: Culex pipiens and Aedes albopictus are closely related to human life, and transmit a variety of viruses, causing serious harm to human health. Cytochrome c oxidase I (COI) gene has been selected as a marker gene for studying phylogeny and molecular evolution of species and is also an effective molecular marker for studying the evolutionary mechanism and systematic reconstruction of diptera insects. Methods: A loop-mediated isothermal amplification (LAMP) method for the rapid and sensitive detection of Cx. pipiens and Ae. albopictus were first described in this study. The experimental results were verified by real-time PCR. Results: Our study showed the lower limit of sample concentration that can be detected by LAMP method is 0.5 pg/µl within 20 min for Cx. pipiens, and 1 pg/µl within 20 min for Ae. albopictus, which were more sensitive than PCR method. Validation tests with field samples showed LAMP method had good specificity and sensitivity and could identify the target species quickly and accurately. Conclusion: The LAMP method developed in this study allowed the rapid and sensitive detection of Cx. pipiens and Ae. albopictus, which will be expected to be used for mass screening in batches of the field.

Characterization of Mu-Like Yersinia Phages Exhibiting Temperature Dependent Infection.

Yersinia pestis is the etiological agent of plague. Marmota himalayana of the Qinghai-Tibetan plateau is the primary host of flea-borne Y. pestis. This study is the report of isolation of Mu-like bacteriophages of Y. pestis from M. himalayana. The isolation and characterization of four Mu-like phages of Y. pestis were reported, which were named as vB_YpM_3, vB_YpM_5, vB_YpM_6, and vB_YpM_23 according to their morphology. Comparative genome analysis revealed that vB_YpM_3, vB_YpM_5, vB_YpM_6, and vB_YpM_23 are phylogenetically closest to Escherichia coli phages Mu, D108 and Shigella flexneri phage SfMu. The role of LPS core structure of Y. pestis in the phages' receptor was pinpointed. All the phages exhibit "temperature dependent infection," which is independent of the growth temperature of the host bacteria and dependent of the temperature of phage infection. The phages lyse the host bacteria at 37°C, but enter the lysogenic cycle and become prophages in the chromosome of the host bacteria at 26°C. IMPORTANCE Mu-like bacteriophages of Y. pestis were isolated from M. himalayana of the Qinghai-Tibetan plateau in China. These bacteriophages have a unique temperature dependent life cycle, follow a lytic cycle at the temperature of warm-blooded mammals (37°Ð¡), and enter the lysogenic cycle at the temperature of its flea-vector (26°Ð¡). A switch from the lysogenic to the lytic cycle occurred when lysogenic bacteria were incubated from lower temperature to higher temperature (initially incubating at 26°C and shifting to 37°C). It is speculated that the temperature dependent lifestyle of bacteriophages may affect the population dynamics and pathogenicity of Y. pestis.

Draft genome sequences of two Legionella dumoffii strains, TEX-KL and NY-23.

Legionella (Fluoribacter) dumoffii is one of the agents causing Legionnaires' disease. Here, we used Illumina second-generation sequencing technology to decipher for the first time the whole-genome sequences of two strains of this species, TEX-KL and NY-23. The assembly results for both strains consist of one chromosome and two plasmids.

Draft genome sequence of an Acinetobacter genomic species 3 strain harboring a bla(NDM-1) gene.

Here we report the draft genome sequence of one Acinetobacter genomic species 3 strain, D499, which harbors the bla(NDM-1) gene. The total length of the assembled genome is 4,103,824 bp, and 3,896 coding sequences (CDSs) were predicted within the genome. A previously unreported bla(NDM-1)-bearing plasmid was identified in this strain.

Identification and characterization of P2-like bacteriophages of Yersinia pestis.

Yersinia pestis is the cause of plague, historically known as the "Black Death". Marmota himalayana in the Qinghai-Tibet Plateau (QTP) natural plague focus is the primary host in China. Although several phages originating from Y. pestis have been characterized. This is the first report of isolation of P2-like phages of Y. pestis from M. himalayana. In this study, the isolation and characterization of three P2-like phages of Y. pestis were reported, which were named as vB_YpM_22, vB_YpM_46 and vB_YpM_50. Comparative genome analysis revealed that vB_YpM_22, vB_YpM_46 and vB_YpM_50 are members of the nonlambdoid P2 family, and are highly similar and collinear with enterobacteriophage P2, plague diagnostic phage L-413C and enterobacteriophage fiAA91-ss. The role of LPS core structure of Y. pestis in the phages' receptor was pinpointed. The findings of this study contribute an advance in our current knowledge of Y. pestis phages and will also play a key role in understanding the evolution of Y. pestis phages.