Objective To investigae microbial community structure of lower respiratory tract in severe hospital-acquired pneumonia(SHAP)patients in intensive care unit(ICU)using metagenomic next-generation sequencing(mNGS).Methods mNGS was performed on bronchoalveolar lavage fluid(BALF)of 84 patients with SHAP.Patients were grouped based on age,smoking status,underlying diseases and duration of artificial airway.The differences in α diversity,β diversity,microbial composition and community structure of airway microbiota were compared between different groups.The differential airway microbiota associated with artificial airway were screened,and microbial co-occurrence networks was constructed to observe the interaction in microorganisms.Results Results of α diversity analysis revealed that diversity and evenness of the microbial community were higher in young adults compared to those of middle-aged patients,while microbial diversity and evenness were significantly reduced in patients with comorbid stroke.In the group of artificial airway treatment,the diversity and uniformity of microorganisms decreased as the duration of artificial airway treatment increased.The diversity was the lowest when the artificial airway treatment lasted for more than 3 days.β diversity analysis confirmed that there were significant differences in the distinct microbial community structures between the>3 days support group and the non-intubated and≤3 days support cohorts.Acinetobacter baumannii was dominant in all groups.The bacterial diversity was significantly higher in the middle-aged group,the non-smoking group,the group without artificial airway therapy,the group without diabetes mellitus,the group with artificial airway therapy≥3 days and the group with chronic lung disease than those of other groups.In particular,pseudomonas aeruginosa,corynebacterium striatum and veillonella parvula were enriched in these groups.Difference analysis showed that there were significant differences in pseudomonas aeruginosa and corynebacterium striatum between the group with artificial airway treatment>3 days,the group without artificial airway therapy and the group with artificial airway treatment≤3 days.Network co-occurrence showed that there may be synergistic or antagonistic relationships between some microorganisms.Conclusion The microbial diversity of the lower respiratory tract in patients with SHAP significantly decreases in the elderly,those with concurrent stroke and those receiving artificial airway treatment.For these groups,rational use of antibiotics should be adopted to guide precise anti-infection treatment.

Objective To investigae microbial community structure of lower respiratory tract in severe hospital-acquired pneumonia(SHAP)patients in intensive care unit(ICU)using metagenomic next-generation sequencing(mNGS).Methods mNGS was performed on bronchoalveolar lavage fluid(BALF)of 84 patients with SHAP.Patients were grouped based on age,smoking status,underlying diseases and duration of artificial airway.The differences in α diversity,β diversity,microbial composition and community structure of airway microbiota were compared between different groups.The differential airway microbiota associated with artificial airway were screened,and microbial co-occurrence networks was constructed to observe the interaction in microorganisms.Results Results of α diversity analysis revealed that diversity and evenness of the microbial community were higher in young adults compared to those of middle-aged patients,while microbial diversity and evenness were significantly reduced in patients with comorbid stroke.In the group of artificial airway treatment,the diversity and uniformity of microorganisms decreased as the duration of artificial airway treatment increased.The diversity was the lowest when the artificial airway treatment lasted for more than 3 days.β diversity analysis confirmed that there were significant differences in the distinct microbial community structures between the>3 days support group and the non-intubated and≤3 days support cohorts.Acinetobacter baumannii was dominant in all groups.The bacterial diversity was significantly higher in the middle-aged group,the non-smoking group,the group without artificial airway therapy,the group without diabetes mellitus,the group with artificial airway therapy≥3 days and the group with chronic lung disease than those of other groups.In particular,pseudomonas aeruginosa,corynebacterium striatum and veillonella parvula were enriched in these groups.Difference analysis showed that there were significant differences in pseudomonas aeruginosa and corynebacterium striatum between the group with artificial airway treatment>3 days,the group without artificial airway therapy and the group with artificial airway treatment≤3 days.Network co-occurrence showed that there may be synergistic or antagonistic relationships between some microorganisms.Conclusion The microbial diversity of the lower respiratory tract in patients with SHAP significantly decreases in the elderly,those with concurrent stroke and those receiving artificial airway treatment.For these groups,rational use of antibiotics should be adopted to guide precise anti-infection treatment.

Objective:To investigate the effects of wza gene deletion in Klebsiella pneumoniae on capsule formation ability and bacteriophage sensitivity. Methods:The wza deletion mutant strain was constructed through a temperature-sensitive plasmid-mediated homologous recombination. The growth curves of W14 and Δ wza were detected by measuring the optical density OD 600. In order to analyze the effect of gene wza on bacterial capsule formation, wild-type strain W14 and Δ wza mutant strain were detected by transmission electron microscope, and their capsule contents were measured by quantifying the uronic acid contents. The plaque assay was used to detect bacterial sensitivity to bacteriophage in wild-type strain W14 and Δ wza mutant strain. The t test was used to compare whether there were differences in the contents of uronic acid in the capsules of wild-type strain W14 and Δ wza mutant strain. Results:The PCR results revealed that the Δ wza mutant strain was successfully constructed. Compared with wild-type strain W14, the growth curves of Δ wza on the solid plates demonstrated a slightly slower growth. However, no difference in growth was observed among wild-type strain W14 and Δ wza mutant strains in LB broth. The transmission electron microscope results showed that wza gene deletion resulted in the loss of capsule in bacteria. The uronic acid content assay suggested that the capsule content was significantly decreased in Δ wza mutant strain (45.963±2.795) μg/ml compared with wild-type strain W14 (138.800±5.201) μg/ml. There was a statistical difference between the two groups ( t=27.233, P<0.001). The plaque assay indicated that bacteria lost its sensitivity to bacteriophage when gene wza was deleted. Conclusion:Deletion of the wza gene impairs bacterial capsule formation ability and can affect bacterial sensitivity to bacteriophage phiW14.

Objective:To express and purify the phage depolymerase from hypervirulent Klebsiella pneumoniae (hv Kp) serotype K1 and validate its function. Methods:Phage that infected serotype K1-type hv Kp was isolated from hospital sewage. The biology and morphology of the phage were determined by plaque assay and transmission electron microscopy. The whole genome of the phage was sequenced by the Illumina HiSeq 2500 platform. The presence of depolymerase was determined by observing the plaque halo. Bioinformatic analysis and prokaryotic protein expression system were further used to predict and identify phage depolymerase. The depolymerase gene fragment was obtained by PCR and cloned into the pET28a expression vector, and the expression and purification of the depolymerase were completed in strain BL21. The depolymerase activities on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates were detected by plaque assay and low-speed centrifugation assay. Results:A lytic phage (phiA2) that infected serotype K1-type hv Kp clinical isolate was isolated from hospital sewage. It was typical of the Caudovirales order and Autographiviridae family, and its whole genome was 43 526 bp in length and contained 51 coding domain sequences. The phage phiA2-derived depolymerase phiA2-dep was predicted, expressed and purified. The plaque assay and low-speed centrifugation assay indicated that the depolymerase phiA2-dep had good lytic activity on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates. Conclusion:Depolymerase phiA2-dep can specifically degrade the capsular polysaccharide of serotype K1-type hv Kp, which has potential application value in treating bacterial infection.

Objective:To investigate the effects of wza gene deletion in Klebsiella pneumoniae on capsule formation ability and bacteriophage sensitivity. Methods:The wza deletion mutant strain was constructed through a temperature-sensitive plasmid-mediated homologous recombination. The growth curves of W14 and Δ wza were detected by measuring the optical density OD 600. In order to analyze the effect of gene wza on bacterial capsule formation, wild-type strain W14 and Δ wza mutant strain were detected by transmission electron microscope, and their capsule contents were measured by quantifying the uronic acid contents. The plaque assay was used to detect bacterial sensitivity to bacteriophage in wild-type strain W14 and Δ wza mutant strain. The t test was used to compare whether there were differences in the contents of uronic acid in the capsules of wild-type strain W14 and Δ wza mutant strain. Results:The PCR results revealed that the Δ wza mutant strain was successfully constructed. Compared with wild-type strain W14, the growth curves of Δ wza on the solid plates demonstrated a slightly slower growth. However, no difference in growth was observed among wild-type strain W14 and Δ wza mutant strains in LB broth. The transmission electron microscope results showed that wza gene deletion resulted in the loss of capsule in bacteria. The uronic acid content assay suggested that the capsule content was significantly decreased in Δ wza mutant strain (45.963±2.795) μg/ml compared with wild-type strain W14 (138.800±5.201) μg/ml. There was a statistical difference between the two groups ( t=27.233, P<0.001). The plaque assay indicated that bacteria lost its sensitivity to bacteriophage when gene wza was deleted. Conclusion:Deletion of the wza gene impairs bacterial capsule formation ability and can affect bacterial sensitivity to bacteriophage phiW14.

Objective:To express and purify the phage depolymerase from hypervirulent Klebsiella pneumoniae (hv Kp) serotype K1 and validate its function. Methods:Phage that infected serotype K1-type hv Kp was isolated from hospital sewage. The biology and morphology of the phage were determined by plaque assay and transmission electron microscopy. The whole genome of the phage was sequenced by the Illumina HiSeq 2500 platform. The presence of depolymerase was determined by observing the plaque halo. Bioinformatic analysis and prokaryotic protein expression system were further used to predict and identify phage depolymerase. The depolymerase gene fragment was obtained by PCR and cloned into the pET28a expression vector, and the expression and purification of the depolymerase were completed in strain BL21. The depolymerase activities on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates were detected by plaque assay and low-speed centrifugation assay. Results:A lytic phage (phiA2) that infected serotype K1-type hv Kp clinical isolate was isolated from hospital sewage. It was typical of the Caudovirales order and Autographiviridae family, and its whole genome was 43 526 bp in length and contained 51 coding domain sequences. The phage phiA2-derived depolymerase phiA2-dep was predicted, expressed and purified. The plaque assay and low-speed centrifugation assay indicated that the depolymerase phiA2-dep had good lytic activity on the capsular polysaccharide of serotype K1-type hv Kp clinical isolates. Conclusion:Depolymerase phiA2-dep can specifically degrade the capsular polysaccharide of serotype K1-type hv Kp, which has potential application value in treating bacterial infection.

Objective: To explore the effects of down-regulated ITGB5 expression on the proliferation of keloid fibroblasts and clarify the possible role of β5-integrin(ITGB5) in keloid. Methods: Construct lentiviral sh-RNA-expression vector targeting ITGB5 and infect keloid fibroblasts, the expression of ITGB5 were detected by Western Blot, the proliferation ability was identified by MTT. Results: The expression quantity of ITGB5 mRNA and protein in KFb group, LV-NC group and LV-KFb group are 1.00±0.00, 1.08±0.05, 0.34±0.01 and 0.91±0.03, 0.93±0.02, 0.28±0.07. Compared with LV-NC group and KFb group, the expression quantity of ITGB5 mRNA and protein in LV-KFb group decreased significantly(P<0.01). Compared with LV-NC group and KFb group, the proliferation rate decreased significantly in LV-KFb group at 48 h(P<0.01). Conclusions These results suggest that ITGB5 can accelerate fibroblasts proliferation in keloids.

OBJECTIVETo investigate the effects of botulinum toxin type A (BTXA) on the expression of alpha smooth muscle actin(alpha-SMA) and myosin-II of fibroblasts in scars. Methods Fibroblasts were isolated from tissue specimens of scars contracture. Cells from passages 3-5 were randomly divided into 3 groups (control group, low BTXA group (1 U/10(6) Cells), and high BTXA group (2.5 U/ 10(6)Cells)). Growth condition of fibroblasts was observed at 1 , 4, 7 day after BTXA treated. Changes of alpha-SMA and myosin-II in fibroblasts were detected by Western blot.

RESULTSFibroblasts grew well in control group. The proliferation was decreased 4 days later in BTXA groups. Lots of apoptotic cells were seen in high BTXA group at 7th day. Proteins of alpha-SMA and myosin-II in fibroblasts were statistically different between BTXA group and control groups at 4th day (P < 0.05). The expression of alpha-SMA and myosin-II in low BTXA group was higher than that in high BTXA group at 7th day (P < 0.05).

CONCLUSIONSBTXA could induce the apoptosis of fibroblasts and decrease the expression of alpha-SMA and myosin-II in fibroblasts. The inhibitory effect was strengthened with BTXA concentration increase within a certain range.

Actins ; metabolism ; Botulinum Toxins, Type A ; pharmacology ; Cicatrix ; Fibroblasts ; drug effects ; metabolism ; Humans ; Muscle, Smooth ; metabolism ; Myosin Type II ; metabolism ; Random Allocation

Objective To evaluate the validity of botulinum toxin type A (BTXA) injections for the treatment of scar contracture.Methods 26 patients with scar contracture were randomly assigned into BTXA group and triamcinolone acetonide (TAC) group.Pinpoint tattooing was performed on each side of each scar in the plane of its longest axis.A template was used to ensure consistent length.These two tattoo points were measured to assess scar contraction at baseline,at every month for a total of 6 months.Histological analysis was conducted to study the physiological environment and immunohistochemistry to detect the expression of α-SMA and myosin-Ⅱ at different groups.Results Scar contraction was more relaxed in BTXA group than that in TAC group after 1 month (P＜0.05),especially in the 6th month (the D value in BTXA group and TAC group was (1.23±0.42) cm,and (0.56±0.33) cm respectively).For immunohistochemistry,the expression of α-SMA and myosin-Ⅱ also decreased in BTXA group (P＜0.05).Conclusions The treatment of scar contracture by suitable BTXA injections is safe and effective.