The small RNA PrrH of Pseudomonas aeruginosa regulates hemolysis and oxidative resistance in bloodstream infection.

Small regulatory RNAs (sRNAs) regulate multiple physiological functions in bacteria, and sRNA PrrH can regulate iron homeostasis and virulence. However, the function of PrrH in Pseudomonas aeruginosa (P. aeruginosa) bloodstream infection (BSI) is largely unknown. The aim of this study was to investigate the role of PrrH in P. aeruginosa BSI model. First, P. aeruginosa PAO1 was co-cultured with peripheral blood cells for 6 h. qRT-PCR results showed a transient up-regulation of PrrH expression at 1 h. Simultaneously, the expression of iron uptake genes fpvA, pvdS and phuR were upregulated. In addition, the use of iron chelator 2,2'-dipyridyl to create low-iron conditions caused up-regulation of PrrH expression, a result similar to the BSI model. Furthermore, the addition of FeCl3 was found to decrease PrrH expression. These results support the hypothesis that the expression of PrrH is regulated by iron in BSI model. Then, to clarify the effect of PrrH on major cells in the blood, we used PrrH mutant, overexpressing and wild-type strains to act separately on erythrocytes and neutrophils. On one hand, the hemolysis assay revealed that PrrH contributes to the hemolytic activity of PAO1, and its effect was dependent on the T3SS system master regulator gene exsA, yet had no association with the hemolytic phospholipase C (plcH), pldA, and lasB elastase genes. On the other hand, PrrH mutant enhanced the oxidative resistance of PAO1 in the neutrophils co-culture assay, H2O2-treated growth curve and conventional plate spotting assays. Furthermore, the katA was predicted to be a target gene of PrrH by bioinformatics software, and then verified by qRT-PCR and GFP reporter system. In summary, dynamic changes in the expression of prrH are iron-regulated during PAO1 bloodstream infection. In addition, PrrH promotes the hemolytic activity of P. aeruginosa in an exsA-dependent manner and negatively regulates katA to reduce the oxidative tolerance of P. aeruginosa.

Corynebacterium lipophilum sp. nov., a lipophilic bacterium isolated from clinical breast specimens and emended description of the species Corynebacterium pilbarense.

Two isolates (MC-18T and MC-17D), representing the Gram-stain-positive, facultatively anaerobic, irregular rod-shaped, non-motile, and non-spore-forming actinobacteria, were isolated from clinical breast specimens in Guangzhou, China. The growth of the isolates is enhanced by supplementing 1% Tween-80 on Luria Bertani agar. Optimal growth of the isolates was observed at 37 °C, pH 7-8, and with 1% (w/v) NaCl on Columbia blood agar. Pairwise comparison of the 16S rRNA gene sequences revealed that isolates MC-18T and MC-17D shared the highest sequence similarities with Corynebacterium liangguodongii 2184T (96.9%), which were lower than the threshold value for species delineation (98.65%). Phylogenetic dendrograms based on the 16S rRNA gene, rpoB gene, and core genomes indicated that two isolates formed a distinct lineage within the genus Corynebacterium. The estimated dDDH, ANIb, ANIm, and AAI values between strain MC-18T and its closely related strains were below the threshold values generally considered for recognizing a new species. The genome DNA G + C contents of both the isolates MC-18T and MC-17D are 60.6%. The two isolates have virulence-related genes of the VF classes of adhesion and antiphagocytosis, and also contain the antimicrobial resistance genes ErmX, mtrA, rpoB2, and RbpA. The major fatty acids (> 10%) of isolates MC-18T and MC-17D were C16:0, C18:1 ω9c, C18:0 and summed feature 5 (anteiso-C18:0 and/or C18:2 ω6,9c). The main respiratory quinone of strain MC-18T was MK-8(H2), and the polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, three unidentified glycolipids, an unidentified aminolipid, and four unidentified phosphoglycolipids. The two isolates lack mycolic acids in the cell envelope. Based on the above findings, the two isolates are considered to represent a novel species of the genus Corynebacterium, for which the name Corynebacterium lipophilum sp. nov. is proposed, with isolate MC-18T (= NBRC 115144T = CCTCC AB 2020201T) as the type strain. An emended description of the Corynebacterium pilbarense is also provided.

Prevalence of mcr-1 in Colonized Inpatients, China, 2011-2019.

In response to the spread of colistin resistance gene mcr-1, China banned the use of colistin in livestock fodders. We used a time-series analysis of inpatient colonization data from 2011-2019 to accurately reveal the associated fluctuations of mcr-1 that occurred in inpatients in response to the ban.

Sandaracinobacteroides hominis gen. nov., sp. nov., isolated from human skin.

Strain SZY PN-1 T, representing a novel Gram-negative, aerobic, non-motile, rod-shaped and yellow-pigmented bacterium, was isolated from a skin sample of a healthy Chinese male. Growth occurred at pH 6.0-8.0 (optimum, pH 7.0) and 10-37 â„ƒ (optimum, 30 â„ƒ) with 0-1.0% (w/v) NaCl in R2A agar. Comparative analysis of the 16S rRNA gene sequences revealed that strain SZY PN-1 T shared high similarities with two invalid-published species, "Sandaracinobacter sibiricus" RB16-17 (97.1%) and "Sandaracinobacter neustonicus" JCM 30734 (96.6%), respectively. Phylogenetic analysis of 16S rRNA gene sequences together with protein-concatemer tree showed that SZY PN-1 T formed a separate branch within the family Sphingosinicellaceae. The DNA G + C content of the strain SZY PN-1 T was 65.0% (genome). The polar lipid profile included phosphatidylethanolamine, phosphatidylglycerol, two sphingoglycolipids, diphosphatidylglycerol, five unidentified glycolipids, and seven unidentified lipids. The predominant fatty acids (> 10.0%) were identified as C18:1 ω7c and/or C18:1 ω6c, C17:1 ω6c, C16:1 ω7c and/or C16:1 ω6c. The major respiratory quinone was Q-10. Based on the phenotypic and genotypic features, a novel genus and species, Sandaracinobacteroides hominis gen. nov., sp. nov. is proposed, with type strain SZY PN-1 T (= KCTC 82150 T = NBRC 114675 T).

Legionella septentrionalis sp. nov., isolated from aquatic environments in the northern PR China.

Four strains (km711T, km714, km542 and km524), representing a novel Legionella species, were isolated from aquatic environments in northern PR China. Cells were Gram-stain-negative, rod-shaped, microaerobic, motile and growth depended on l-cysteine. They grew at 25‒42 °C (optimum, 35‒37 °C) and could tolerate up to 1.5 % (w/v) NaCl (optimum, 0.5 %). The major fatty acids (>5 %) of the type strain km711T were C17 : 0 anteiso, C15 : 0 anteiso, iso-C16 : 0 and C16 : 1 ω7c and/or iso-C15 : 0 2OH. The pairwise comparison values were <96.1 % for 16S rRNA gene sequences, 23.3‒28.7 % interspecies variation for mip gene sequences, <93.6 % average nucleotide identity and <72.8 % average amino acid identity between these four strains and related type strains within the genus Legionella. The phylogenetic tree based on the four concatenated genes (16S rRNA, mip, rpoB and rnpB) and protein-concatamer tree based on concatenation of 21 protein markers both revealed that these four strains formed a separate phylogenetic branch cluster within the genus Legionella. The results of phenotypic and genotypic features suggest that these four strains represent a novel species of the genus Legionella, for which the name Legionella septentrionalis sp. nov. is proposed (type strain km711T=KCTC 15655T=NBRC 113219T).

Application of Sigma metrics in the quality control strategies of immunology and protein analytes.

BACKGROUND: Six Sigma (6σ) is an efficient laboratory management method. We aimed to analyze the performance of immunology and protein analytes in terms of Six Sigma. METHODS: Assays were evaluated for these 10 immunology and protein analytes: Immunoglobulin G (IgG), Immunoglobulin A (IgA), Immunoglobulin M (IgM), Complement 3 (C3), Complement 4 (C4), Prealbumin (PA), Rheumatoid factor (RF), Anti streptolysin O (ASO), C-reactive protein (CRP), and Cystatin C (Cys C). The Sigma values were evaluated based on bias, four different allowable total error (TEa) and coefficient of variation (CV) at QC materials levels 1 and 2 in 2020. Sigma Method Decision Charts were established. Improvement measures of analytes with poor performance were recommended according to the quality goal index (QGI), and appropriate quality control rules were given according to the Sigma values. RESULTS: While using the TEaNCCL , 90% analytes had a world-class performance with σ>6, Cys C showed marginal performance with σ<4. While using minimum, desirable, and optimal biological variation of TEa, only three (IgG, IgM, and CRP), one (CRP), and one (CRP) analytes reached 6σ level, respectively. Based on σNCCL that is calculated from TEaNCCL , Sigma Method Decision Charts were constructed. For Cys C, five multi-rules (13s /22s /R4s /41s /6X , N = 6, R = 1, Batch length: 45) were adopted for QC management. The remaining analytes required only one QC rule (13s , N = 2, R = 1, Batch length: 1000). Cys C need to improve precision (QGI = 0.12). CONCLUSIONS: The laboratories should choose appropriate TEa goals and make judicious use of Sigma metrics as a quality improvement tool.

Compromised Flap Salvage With Closed Incision Negative Pressure Therapy Under Real-Time Indocyanine Green Fluorescence Assessment.

BACKGROUND: Skin flap transfer is a commonly used technique by surgeons; however, compromised blood flow may result in flap ischemia and necrosis. We describe the use of closed incision negative pressure therapy (ciNPT) to help manage skin flap reconstructions with indocyanine green fluorescence angiography (ICG-FA) to assess perfusion of the flaps before and after ciNPT. METHODS: Three female and 5 male patients underwent various skin flap reconstructions, including local flaps, pedicled flaps, and propeller flaps, for wound defects related to trauma, infection, or cancer. After flap setting and suturing, ciNPT (-125 mm Hg) was applied to the closed incision for 7 days. Perfusion was assessed using ICG-FA before applying ciNPT and again at 24 hours later. The Shapiro-Wilk test and Wilcoxon signed rank test were used in statistical analysis. RESULTS: Initial postoperative survival was observed for all skin flaps; however, 1 flap failed after 2 weeks due to uncontrolled infection. The remaining 7 flaps healed well without any surgical revision. All patients were initially determined to have impaired flap perfusion; however, skin flap perfusion was significantly higher after ciNPT than before ciNPT in each case (P = 0.012). CONCLUSIONS: This study showed good healing outcomes for skin flap reconstructions without complications, despite the fact that each flap had compromised flap perfusion to some extent during the surgery. This case series is novel in that it used laser-assisted ICG-FA to provide a real-time assessment of skin flap perfusion before and after ciNPT.

Haemophilus seminalis sp. nov., isolated from human semen.

Two Haemophilus-like isolates with similar biochemical characteristics, designated strains SZY H1T and SZY H2, were isolated from human semen specimens. Cells were Gram-negative, non-motile, non-acid-fast, pleomorphic rods or coccobacilli. The major fatty acids (>10 %) were C16 : 0, C14 : 0, iso-C16 : 0 and/or C14 : 0 3-OH and C16 : 1 ω6c and/or C16 : 1 ω7c. The polar lipids were determined to be phosphatidylethanolamine, phosphatidylglycerol, an unidentified phospholipid, an unidentified aminophospholipid, two unidentified polar lipids and four unidentified aminolipids. The major polyamine was found to be cadaverine. The near-full-length (1462 nt) 16S rRNA gene sequences analysis showed the two isolates were nearly identical (>99.8 %), and closely matched Haemophilus haemolyticus ATCC 33390T with 98.9-99.1 % sequence similarities. Phylogenetic analysis based on 16S rRNA gene sequences and concatenation of 30 protein markers also revealed that the isolates clustered together with H. haemolyticus ATCC 33390T, and formed a distinct lineage well separated from the other members of the genus Haemophilus. Further, the average nucleotide identity values between the two isolates and their related species were below the established cut-off values for species delineation (95 %). Based on these findings, the two isolates are considered to represent a new species of the genus Haemophilus, for which name Haemophilus seminalis sp. nov. is proposed. The type strain is SZY H1T (=NBRC 113782T=CGMCC 1.17137T).

Francisella salimarina sp. nov., isolated from coastal seawater.

Four strains (SYSU SYW-1T, SYW-2, SYW-3 and XLW-1) were isolated from seawater near the shore in Guangdong Province, China. Cells were Gram-stain-negative, aerobic, non-motile and non-spore-forming. Growth was observed at a temperature range of 16-40 °C (optimum, 32 °C), a pH range of 4-8 (optimum, pH 7) and in the presence of up to 10 % (w/v) NaCl. The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and an unidentified phospholipid. The respiratory quinone was ubiquinone 8 (UQ-8), and the predominant fatty acids were C18 : 0 3-OH, C10 : 0, C14 : 0 and C18 : 1ω9c. Comparison of 16S rRNA gene and genome sequences confirmed that these strains represented a novel member of the genus Francisella, with less than 98.8 % 16S rRNA gene sequence similarity and less than 95 % genomic average nucleotide identity to recognized Francisella species. The phylogenetic tree based on 16S rRNA gene sequences and the protein-concatamer tree based on a concatenation of 28 protein marker sequences both indicated that the strains clustered with 'Francisella salina' TX07-7308 and 'Francisella marina' E95-16, but formed a distinct lineage group among the other members of the genus Francisella. The DNA G+C contents of the four strains were determined to be 32.9, 32.7, 32.9 and 32.9 %, respectively (genome). On the basis of phenotypic and genotypic features, the strains are considered to represent a novel species of the genus Francisella, for which the name Francisella salimarina sp. nov. is proposed. The type strain is SYSU SYW-1T (=CGMCC 1.17031T=NBRC 113781T).

Vogesella urethralis sp. nov., isolated from human urine, and emended descriptions of Vogesella perlucida and Vogesella mureinivorans.

A novel Vogesella strain, YM-1T, was recovered from human urine in PR China in 2017. Cells of strain YM-1T were Gram-stain-negative, rod-shaped, aerobic, motile, non-spore-forming and poly-ß-hydroxybutyrate-accumulating. The strain contained C16:1ω6c/C 16:1ω7c, C16:0 and C18:0ω7c as major fatty acids; phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and an unidentified phospholipid as major polar lipids; and ubiquinone-8 as the predominant respiratory quinone. Comparison of 16S rRNA gene sequences indicated that this strain had highest similarities to Vogesella perlucida DS-28T (98.8 %) and Vogesella mureinivorans 389T (98.1 %). The results of phylogenetic analysis based on the 16S rRNA gene sequences revealed that the novel strain was clustered and well separated with V. perlucida DS-28T and V. mureinivorans 389T within the genus Vogesella. The average nucleotide identity (ANI) and amino acid identity (AAI) analyses showed that this strain was not identified as V. perlucida DS-28T or V. mureinivorans 389T, with values well below the threshold limit for species demarcation (ANI <88.1 %, AAI <88.6 %). Based on the above results, strain YM-1T is proposed to be a novel species of the genus Vogesella with the name Vogesella urethralis sp. nov. (YM-1T=NBRC 113779=CGMCC 1.17135).

Antibodies against atypical pathogens and respiratory viruses detected by Pneumoslide IgM test in adults with community-acquired pneumonia in Guangzhou City.

BACKGROUND: To detect the serum antibodies against respiratory viruses and atypical pathogens in adults with community-acquired pneumonia (CAP) in Guangzhou City (Guangdong province, China). METHODS: A retrospective study was carried out with samples from 685 adults who were admitted with CAP and 108 non-CAP control patients. Atypical pathogens and respiratory viruses in serum were detected using the Pneumoslide IgM test from Vircell, Spain. All patients were divided into 6 groups according to age: 18-24, 25-44, 45-59, 60-74, 75-89, and >90. RESULTS: The total positive rate of CAP was 35.4%, which was highest in the 18-24 age group (P < .05). The highest positive rate, 17.11%, was observed for Mycoplasma pneumoniae (MP). The mean age of MP-infected patients was higher than that of the controls (P < .05). The positive rates for influenza B (INFB), Legionella pneumophila (LP1), Coxiella burnetii (COX), influenza A (INFA), parainfluenza virus (PIV), respiratory syncytial virus (RSV), Chlamydophila pneumoniae (CP), and adenovirus (ADV) were 5.56%, 3.07%, 2.63%, 2.34%, 1.90%, 1.61, 0.88%, and 0.29%, respectively. There were 4.37% of patients with CAP having multiple infections. The main symptoms observed in the 685 CAP patients were cough and sputum production, in 78.4% and 67.4%. Fever was followed by 54% of CAP patients. Dyspnea (39.1%), anorexia (36.8%), increased thirst (26.7%), chills (18.7), headache (14.6%), and nausea (13.1%) were also frequently observed in the CAP patients. CONCLUSIONS: MP infection was the most common in adult CAP patients in Guangzhou City with the highest positive rate in the 18-24 age groups.

Facilibium subflavum gen. nov., sp. nov. and Cysteiniphilum halobium sp. nov., new members of the family Fastidiosibacteraceae isolated from coastal seawater.

Two Francisella-like bacteria, designated strains SYSU SYW-5T and SYSU SYW-6T, were isolated from coastal seawater sampled at Huizhou Double-Moon Bay, Guangdong Province, PR China. Cells were found to be Gram-stain-negative, non-motile, non-spore-forming and of pleomorphic shape (coccobacilli or rod). Chemotaxonomic analysis of the plasma membrane revealed ubiquinone-8 as the respiratory quinone, and saturated branched-chain (anteiso-C15 : 0) and saturated straight-chain (C18 : 0) fatty acids as major components (>8 % of total fatty acid). The major polar lipids comprised diphosphatidylglycerol (cardiolipin), phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine, as well as an unidentified aminophospholipid and an unidentified phospholipid in SYSU SYW-5T, and two unknown polar lipids in SYSU SYW-6T. Comparison of 16S rRNA gene sequences showed that SYSU SYW-5T had maximum similarity to Fastidiosibacter lacustris SYSU HZH-2T (93.4 %), while SYSU SYW-6Thad maximum similarity to Cysteiniphilum litorale SYSU D3-2T (97.5 %). Phylogenetic dendrograms based on 16S rRNA genes and 31 concatenated protein markers revealed that the two novel strains represent a distinct lineage within the family Fastidiosibacteraceae. The average nucleotide identity and in silico DNA-DNA hybridization values between the two isolates and their related species were well below the threshold limit for species delineation (<89.2 and <35 %, respectively). Based on the above results, strain SYSU SYW-5T is proposed to be a novel species of a new genus with the name Facilibium subflavum gen. nov., sp. nov. (SYSU SYW-5T = DSM 103991T= KCTC 52556T), and strain SYSU SYW-6T is proposed to be a novel species of genus Cysteiniphilum with the name Cysteiniphilumhalobium sp. nov. (SYSU SYW-6T=DSM 103992T=KCTC 52558T).

Serratia microhaemolytica sp. nov., isolated from an artificial lake in Southern China.

A Gram-stain negative, facultatively anaerobic, rod-shaped, non-motile and non-spore forming bacterium, designated ZS-11T, was isolated from an artificial freshwater lake in Guangzhou city, Guangdong province, China. Growth of strain ZS-11T was observed at the temperature 18-42 °C (optimum 32-37 °C), pH 6.0-8.0 (optimum 7.0) and 0.5-3.0% (w/v) NaCl (optimum 0.5%, w/v), and also found to be enhanced in the presence of CO2. Pairwise comparison of 16S rRNA gene sequences showed that the strain shared high similarities with Serratia entomophila DSM 12358T (96.1%), Serratia ficaria DSM 4569T (96.0%), Serratia plymuthica DSM 4540T (96.0%), Rahnella victoriana FRB 225T (95.9%) and Rouxiella badensis DSM 100043T (95.8%). The phylogenomic dendrograms showed that strain ZS-11T formed a distinct cluster within the clade of the genus Serratia. The major fatty acids (> 20%) present in the cells were C16:0, C16:1ω7c/C16:1ω6c and C18:1ω7c/C18:1ω6c, which were consistent with those of S. entomophila CCUG 55496T and Serratia liquefaciens CCUG 9285T. The DNA G + C content for the genome was 49.3%. Based on these phenotypic and genotypic data, strain ZS-11T is considered to represent a new species of the genus Serratia, for which the name Serratia microhaemolytica sp. nov. is proposed. The type strain is ZS-11T (= CCTCC AB 2018040T = KCTC 62413T).

Pseudofrancisella aestuarii gen. nov., sp. nov., a novel member of the family Francisellaceae isolated from estuarine seawater.

A Gram-negative, aerobic, non-motile and non-spore forming bacterium, designated strain SYSU WZ-2T, was isolated from an estuarine seawater sample. Growth of strain SYSU WZ-2T was observed at temperature range of 10-40° C (optimum, 32 °C), pH range of 6-10 (optimum, pH 7-8) and in the presence of up to 5.0% NaCl (w/v). The DNA G+C content of the novel strain was determined to be 30.1% (genome). The major polar lipids were found to be diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, an unidentified aminolipid, two unidentified aminophospholipids and two unidentified phospholipids. The major fatty acids were C18:0 3-OH (27.5%), C18:1ω9c (19.3%), C16:0 (17.0%) and C14:0 (12.9%). The respiratory quinone was found to be ubiquinone Q8. Pairwise comparison of the 16S rRNA gene sequence showed that strain SYSU WZ-2T shares high identities with members of the genera Francisella (94.8-95.9%) and Allofrancisella (93.8-94.2%). The phylogenetic dendrograms based on 16S rRNA gene sequences with the members of the family Francisellaceae showed that the strain SYSU WZ-2T formed a distinct phylogenetic lineage well separated from the members of the genera Francisella and Allofrancisella. MALDI-TOF mass spectrometric analysis also depicted a different profile for strain SYSU WZ-2T compared with those of members of the genera Francisella and Allofrancisella. Based on the above results and differences in phenotypic and chemotaxonomic features, strain SYSU WZ-2T is characterized to represent a new species of a novel genus, for which the name Pseudofrancisella aestuarii gen. nov., sp. nov. is proposed (type strain SYSU WZ-2T = KCTC 52557T = CGMCC 1.13718T).

The standardization of the report for urine cell counting-A converting factor for Sysmex UF-1000i.

BACKGROUND: Multicenter laboratory may apply both automated flow cytometer and microscopy for urinalysis. Automated flow cytometer such as Sysmex UF-1000i evaluates particles with native urine without centrifugation and reports as "counts per µL." Microscopic examination recommended as the reference method for urine sediment analysis reports results as "counts per HPF (or µL)." Moreover, some results from flow cytometer are needed to be checked visually under microscopy. Therefore, it is worth to establish the consistency of the results from these two methods. METHODS: Urine specimens from 412 patients were examined with Sysmex UF-1000i and manual microscopy using FAST-READ disposable counting chambers. White blood cell (WBC) and red blood cell (RBC) counting results from UF-1000i after transferred with the converting factor (0.297) we estimated were compared with that from microscopic examination. Method comparison was performed using Passing-Bablok analysis. RESULTS: After transferred with the converting factor (0.297), cell counting results from UF-1000i showed a good correlation with that derived by the reference method (R2 was 0.868 for RBCs (P < 0.001), 0.882 for WBCs (P < 0.001)). Passing-Bablok analysis showed no systematic difference (intercept estimate, -1 [95%CI, -7 to 3] and slightly proportional (slope estimate, 1.2 [95%CI, 1.0 to 1.7]) bias between concentrations of cells measured by manual microscopy and Sysmex UF-1000i using the converting factor. CONCLUSION: The converting factor (0.297) helps to transfer "counts per µL (non-centrifugal urine)" to "counts per µL (equal to centrifugal urine)," and to keep the urine particle analysis results of Sysmex UF-1000i consistent with the results from the reference method.

Promoter Variation and Gene Expression of mcr-1-Harboring Plasmids in Clinical Isolates of Escherichia coli and Klebsiella pneumoniae from a Chinese Hospital.

Next-generation sequencing of 6 mcr-1-harboring Escherichia coli and Klebsiella pneumoniae isolates collected from a tertiary care hospital in China revealed significant sequence variations in the regions flanking the mcr-1 gene. While sequence variations significantly affected the expression and promoter activity of mcr-1, the mcr-1 gene expression levels did not correlate with the in vitro colistin resistance levels, which warrants further in-depth investigations.

Sub-inhibitory concentrations of fluoroquinolones increase conjugation frequency.

Bacteria are subjected to sub-minimal inhibitory concentrations (sub-MIC) of antibiotics in various niches where the low-dosage treatment plays a key role in antibiotic resistance selection. However, the mechanism of sub-MIC of antibiotics on the resistant gene transfer is largely unknown. Here, we used Escherichia coli SM10λpir in which the RP4 plasmid was chromosomally-integrated as the donor strain, to investigate the effects of sub-MIC of Ciprofloxacin(Cip) or Levofloxacin(Lev) on conjugational transfer of mobilisable plasmid-pUCP24T from SM10λpir to Pseudomonas aeruginosa. The results showed that the transfer frequency was significantly increased by treating E. coli with sub-MIC of Cip or Lev. To investigate the molecular mechanisms, complete transcriptome sequencing was performed. We found that the sub-MIC of Cip or Lev enhanced the expression of several genes on the RP4 plasmid, which was consistent with the conjugation efficiency. Moreover, the expression of genes associated with SOS response in donor SM10λpir was increased, but had no correlation with conjugation efficiency. These findings suggested that sub-MIC of Cip or Lev may promote conjugational transfer by up-regulating the expression of conjugation associated genes via an SOS-independent mechanism.

Kinetics of Ethylene Epoxidation on a Promoted Ag/α-Al2 O3 Catalyst-The Effects of Product and Chloride Co-Feeds on Rates and Selectivity.

The overall chloriding effectiveness factor (Z*), defined as the ratio of ethyl chloride concentration in parts per million to the sum of ethylene and ethane concentration in mole percent multiplied by a weighting factor to account for their efficacy in removing chlorine-adatoms from the surface, was used as a parameter to account for the effects of chlorine on the kinetics of ethylene epoxidation on a highly promoted 35 wt % Ag/α-Al2 O3 catalyst. An increase in O2 order (≈0.7 to 1) and a decrease in C2 H4 order (≈0.5 to <0) with increasing Z* (Z*=2.1, 3.4, 5.2, and 8.9) was observed implicating kinetic relevance of O2 activation on chloride-promoted silver catalysts. Carbon dioxide co-feed (1-5 mol %) was found to promote ethylene oxide selectivity as CO2 co-feed reversibly inhibits CO2 synthesis rates (-0.6 order) more than ethylene oxide synthesis rates (-0.49 order) at all Z* values. Ethylene oxide and CO2 rates were found to be invariant with ethylene oxide (0-0.5 mol %) and acetaldehyde (0-1.7 ppm) co-feeds, suggesting that there is minimal product inhibition under reaction conditions. A model involving a common reaction intermediate for ethylene oxide and carbon dioxide synthesis and two types of atomically adsorbed oxygen species-nucleophilic and electrophilic oxygen-is proposed to plausibly describe the observed reaction rate dependencies and selectivity trends as a function of the chloriding effectiveness.

Fastidiosibacter lacustris gen. nov., sp. nov., isolated from a lake water sample, and proposal of Fastidiosibacteraceae fam. nov. within the order Thiotrichales.

AFrancisella-like bacterium, designated strain SYSU HZH-2T, was isolated from a water sample collected from Haizhu Lake, Guangzhou, China. The bacterium was fastidious, and required an exogenous source of l-cysteine for its growth on artificial media. Cells were Gram-stain-negative, coccobacilli, non-motile and non-spore-forming. The strain shared highest 16S rRNA gene sequence similarities with Cysteiniphilum litorale SYSU D3-2T (94.6 % identity), Fangia hongkongensis UST040201-002T (93.2 %) and Caedibacter taeniospiralis 51T (91.6 %). This strain possessed ubiquinone-8 as the respiratory quinone; diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol as the known polar lipids, and anteiso-C15 : 0 and C18 : 0 as the major fatty acids (>10 % of total fatty acids). The dendrograms based on 16S rRNA gene sequence analysis showed that it formed a separate cluster along with Cysteiniphilum litorale SYSU D3-2T, Caedibactertaeiniospiralis 51T and Fangia hongkongensis UST040201-002T. Based on the 16S rRNA gene sequence identity and differences in other phenotypic characteristics, the strain is considered to represent a novel species of a novel genus, for which the name Fastidiosibacter lacustris gen. nov., sp. nov. is proposed. The type strain of the type species Fastidiosibacter lacustris is SYSU HZH-2T (=NBRC 112274T = CGMCC 1.15950T). Additionally, the new taxon along with the genera Caedibacter, Cysteiniphilum and Fangia (family unassigned) were distinctly separated from the related families Francisellaceae, Piscirickettsiaceae and Thiotrichaeae in the phylogenetic trees. Therefore, we proposed a new family Fastidiosibacteraceae fam. nov. within the order Thiotrichales to accommodate these four genera.

Modified Design of Anterolateral Thigh Flap for Total Pharyngolaryngectomy Reconstruction: A Single-Center Experience.

BACKGROUND: Defects after total pharyngolaryngectomy for hypopharyngeal cancer often require reconstruction via free tissue transfer. Recently, anterolateral thigh (ALT) flap has become the gold standard in many centers because of its advantages with respect to versatility, minimal donor-site morbidity, good speech quality, and relatively low fistula and anastomotic leakage rates. Moreover, ALT allows 2 surgical teams to work simultaneously. However, the height of the parallelogram in the ALT design for neoesophagus reconstruction is usually set at a minimum of 9.4 cm (circumference, 2πr) for smooth food passage. Because this height exceeds 8 cm, the donor site may not be closed primarily, which highly depends on the patient's body habitus and the skin tone or quality and requires other methods, such as local flap or skin graft for wound closure, which subsequently increase operating time and donor-site complication rate. OBJECTIVES: Thus, we aimed to construct a simple and modified ALT design that will not only include the advantages described earlier but also provide adequate donor-site primary closure without jeopardizing complication rates. METHODS: Ten patients with hypopharyngeal cancer underwent reconstructive surgery using our modified ALT design after total pharyngolaryngectomy between 2010 and 2017. Our modified ALT design converts this "classical" shape into a parallelogram so that the height of the modified design is always less than 8 cm, thus allowing for easy primary closure of the wound. RESULTS: The donor-site defects of all 10 patients were closed primarily. No donor-site complications and partial or total flap loss were observed. One patient experienced persistent wound infection with dehiscence, for which debridement was performed. The stricture and fistula rates were 10% (n = 1) and 20% (n = 2), respectively. The mean follow-up time is approximately 1 year. CONCLUSIONS: Minimizing donor-site morbidity is an important goal in reconstructive surgery. Our modified ALT flap design is simple, enabling easy primary closure of the donor-site defect, with improved results for the patient and operators. Furthermore, this design is also suitable for ALT flaps with widths larger than 8 cm.