This study investigated the mechanism of Chaishao Kaiyu Decoction in improving hippocampal neuroinflammation in depressed rats based on complement component 3(C3)/C3 receptor(C3aR). A total of 60 SD rats were randomly divided into a blank group, a model group, high, medium, and low dose groups of Chaishao Kaiyu Decoction, and a positive drug group, with 10 rats in each group. Except for the blank group, chronic unpredictable mild stress(CUMS) was used to construct depression models in other groups. Sucrose preference, open-field experiment, forced swimming, and water maze were used to detect the changes in depression-like behavior in each group. Enzyme-linked immunosorbent assay(ELISA) was used to detect the serum inflammatory factor level in rats, and hematoxylin-eosin(HE) staining and Nissl staining were employed to observe the pathological damage of hippocampal neurons. Golgi-Cox staining was used to observe the dendritic spine damage of hippocampal neurons, and immunofluorescence and Western blot were utilized to detect the expression of microglial marker Iba-1 and C3/C3aR protein in the hippocampus of rats. The behavioral results showed that compared with the model group, Chaishao Kaiyu Decoction could significantly strengthen the sugar water preference, increase the distance and number of voluntary activities, shorten the immobility time in forced swimming and the successful incubation period of positioning navigation, and prolong the stay time of space exploration in the target quadrant. ELISA results showed that the content of inflammatory factors in the hippocampus of depressed rats was significantly higher than that of the blank group, and the content of inflammatory factors decreased significantly after the intervention of Chaishao Kaiyu Decoction. In addition, Chaishao Kaiyu Decoction could relieve pathological damage such as cell swelling and loose arrangement of hippocampus tissue. In the Western blot experiment, the expression levels of C3 and C3aR proteins in the model group were higher than those in the blank group, while the expression of C3 and C3aR in Chaishao Kaiyu Decoction could be down-regulated. Immunofluorescence results showed that compared with the model group, the fluorescence intensity of microglia marker Iba-1 decreased significantly after the intervention of Chaishao Kaiyu Decoction and positive drugs. The antidepressant effect of Chaishao Kaiyu Decoction may be related to the down-regulation of C3/C3aR signaling pathway-related proteins, thus alleviating hippocampal inflammation.
Animals ; Hippocampus/metabolism* ; Rats, Sprague-Dawley ; Drugs, Chinese Herbal/administration & dosage* ; Rats ; Male ; Depression/metabolism* ; Complement C3/metabolism* ; Receptors, Complement/metabolism* ; Humans ; Neuroinflammatory Diseases/genetics*

This study investigated the effects and underlying mechanisms of vanillic acid(VA) against cardiac fibrosis(CF) induced by isoproterenol(ISO) in mice. Male C57BL/6J mice were randomly divided into control group, VA group(100 mg·kg~(-1), ig), ISO group(10 mg·kg~(-1), sc), ISO + VA group(10 mg·kg~(-1), sc + 100 mg·kg~(-1), ig), ISO + dynamin-related protein 1(Drp1) inhibitor(Mdivi-1) group(10 mg·kg~(-1), sc + 50 mg·kg~(-1), ip), and ISO + VA + Mdivi-1 group(10 mg·kg~(-1), sc + 100 mg·kg~(-1), ig + 50 mg·kg~(-1), ip). The treatment groups received the corresponding medications once daily for 14 consecutive days. On the day after the last administration, cardiac functions were evaluated, and serum and cardiac tissue samples were collected. These samples were analyzed for serum aspartate aminotransferase(AST), lactate dehydrogenase(LDH), creatine kinase-MB(CK-MB), cardiac troponin I(cTnI), reactive oxygen species(ROS), interleukin(IL)-1β, IL-4, IL-6, IL-10, IL-18, and tumor necrosis factor-α(TNF-α) levels, as well as cardiac tissue catalase(CAT), glutathione(GSH), malondialdehyde(MDA), myeloperoxidase(MPO), superoxide dismutase(SOD), total antioxidant capacity(T-AOC) activities, and cytochrome C levels in mitochondria and cytoplasm. Hematoxylin-eosin, Masson, uranium acetate and lead citrate staining were used to observe morphological and mitochondrial ultrastructural changes in the cardiac tissues, and myocardial injury area and collagen volume fraction were calculated. Flow cytometry was applied to detect the relative content and M1/M2 polarization of cardiac macrophages. The mRNA expression levels of macrophage polarization markers [CD86, CD206, arginase 1(Arg-1), inducible nitric oxide synthase(iNOS)], CF markers [type Ⅰ collagen(Coll Ⅰ), Coll Ⅲ, α-smooth muscle actin(α-SMA)], and cytokines(IL-1β, IL-4, IL-6, IL-10, IL-18, TNF-α) in cardiac tissues were determined by quantitative real-time PCR. Western blot was used to detect the protein expression levels of Coll Ⅰ, Coll Ⅲ, α-SMA, Drp1, p-Drp1, voltage-dependent anion channel(VDAC), hexokinase 1(HK1), NOD-like receptor protein 3(NLRP3), apoptosis-associated speck-like protein(ASC), caspase-1, cleaved-caspase-1, gasdermin D(GSDMD), cleaved N-terminal gasdermin D(GSDMD-N), IL-1β, IL-18, B-cell lymphoma-2(Bcl-2), B-cell lymphoma-xl(Bcl-xl), Bcl-2-associated death promoter(Bad), Bcl-2-associated X protein(Bax), apoptotic protease activating factor-1(Apaf-1), pro-caspase-3, cleaved-caspase-3, pro-caspase-9, cleaved-caspase-9, poly(ADP-ribose) polymerase-1(PARP-1), and cleaved-PARP-1 in cardiac tissues. The results showed that VA significantly improved cardiac function in mice with CF, reduced myocardial injury area and cardiac index, and decreased serum levels of AST, CK-MB, cTnI, LDH, ROS, IL-1β, IL-6, IL-18, and TNF-α. VA also lowered MDA and MPO levels, mRNA expressions of IL-1β, IL-6, IL-18, and TNF-α, and mRNA and protein expressions of Coll Ⅰ, Coll Ⅲ, and α-SMA in cardiac tissues, and increased serum levels of IL-4 and IL-10, cardiac tissue levels of CAT, GSH, SOD, and T-AOC, and mRNA expressions of IL-4 and IL-10. Additionally, VA ameliorated cardiac pathological damage, inhibited myocardial cell apoptosis, inflammatory infiltration, and collagen fiber deposition, reduced collagen volume fraction, and alleviated mitochondrial damage. VA decreased the ratio of F4/80~+CD86~+ M1 cells and the mRNA expressions of CD86 and iNOS in cardiac tissue, and increased the ratio of F4/80~+CD206~+ M2 cells and the mRNA expressions of CD206 and Arg-1. VA also reduced protein expressions of p-Drp1, VDAC, NLRP3, ASC, caspase-1, cleaved-caspase-1, GSDMD, GSDMD-N, IL-1β, IL-18, Bad, Bax, Apaf-1, cleaved-caspase-3, cleaved-caspase-9, cleaved-PARP-1, and cytoplasmic cytochrome C, and increased the expressions of HK1, Bcl-2, Bcl-xl, pro-caspase-3, pro-caspase-9 proteins, as well as the Bcl-2/Bax and Bcl-xl/Bad ratios and mitochondrial cytochrome C content. These results indicate that VA has a significant ameliorative effect on ISO-induced CF in mice, alleviates ISO-induced oxidative damage and inflammatory response, and its mechanism may be closely related to the inhibition of Drp1/HK1/NLRP3 and mitochondrial apoptosis signaling pathways, suppression of myocardial cell inflammatory infiltration and collagen fiber deposition, reduction of collagen volume fraction and CollⅠ, Coll Ⅲ, and α-SMA expressions, thus mitigating CF.
Animals ; Isoproterenol/adverse effects* ; Male ; Mice ; Signal Transduction/drug effects* ; Vanillic Acid/administration & dosage* ; Dynamins/genetics* ; Mice, Inbred C57BL ; Fibrosis/genetics* ; Apoptosis/drug effects* ; Mitochondria/metabolism* ; NLR Family, Pyrin Domain-Containing 3 Protein/genetics* ; Myocardium/metabolism* ; Humans

This study aims to investigate the effect of Chaijin Jieyu Anshen Formula on the neuroinflammation of rats with insomnia complicated with depression through the regulation of triggering receptor expressed on myeloid cells 2(TREM2)/complement protein C1q signaling pathway. Rats were randomly divided into a normal group, a model group, a positive drug group, as well as a high, medium, and low-dose groups of Chaijin Jieyu Anshen Formula, with 10 rats in each group. Except for the normal group, the other groups were injected with p-chlorophenylalanine and exposed to chronic unpredictable mild stress to establish the rat model of insomnia complicated with depression. The sucrose preference experiment, open field experiment, and water maze test were performed to evaluate the depression in rats. Enzyme-linked immunosorbent assay was employed to detect serum 5-hydroxytryptamine(5-HT), dopamine(DA), and norepinephrine(NE) levels. Hematoxylin and eosin staining and Nissl staining were used to observe the damage in nucleus accumbens neurons. Western blot and immunofluorescence were performed to detect TREM2, C1q, postsynaptic density 95(PSD-95), and synaptophysin 1(SYN1) expressions in rat nucleus accumbens, respectively. Golgi-Cox staining was utilized to observe the synaptic spine density of nucleus accumbens neurons. The results show that, compared with the model group, Chaijin Jieyu Anshen Formula can significantly increase the sucrose preference as well as the distance and number of voluntary activities, shorten the immobility time in forced swimming test and the successful incubation period of positioning navigation, and prolong the stay time of space exploration in the target quadrant test. The serum 5-HT, DA, and NE contents in the model group are significantly lower than those in the normal group, with the above contents significantly increased after the intervention of Chaijin Jieyu Anshen Formula. In addition, Chaijin Jieyu Anshen Formula can alleviate pathological damages such as swelling and loose arrangement of tissue cells in the nucleus accumbens, while increasing the Nissl body numbers. Chaijin Jieyu Anshen Formula can improve synaptic damage in the nucleus accumbens and increase the synaptic spine density. Compared to the normal group, the expression of C1q protein was significantly higher in the model group, while the expression of TREM2 protein was significantly lower. Compared to the model group, the intervention with Chaijin Jieyu Anshen Formula significantly downregulated the expression of C1q protein and significantly upregulated the expression of TREM2. Compared with the model group, the PSD-95 and SYN1 fluorescence intensity is significantly increased in the groups receiving different doses of Chaijin Jieyu Anshen Formula. In summary, Chaijin Jieyu Anshen Formula can reduce the C1q protein expression, relieve the TREM2 inhibition, and promote the synapse-related proteins PSD-95 and SNY1 expression. Chaijin Jieyu Anshen Formula improves synaptic injury of the nucleus accumbens neurons, thereby treating insomnia complicated with depression.
Animals ; Male ; Rats ; Nucleus Accumbens/metabolism* ; Drugs, Chinese Herbal/administration & dosage* ; Depression/complications* ; Membrane Glycoproteins/genetics* ; Rats, Sprague-Dawley ; Sleep Initiation and Maintenance Disorders/complications* ; Neurons/metabolism* ; Receptors, Immunologic/genetics* ; Signal Transduction/drug effects* ; Synapses/metabolism*

OBJECTIVE: To explore clinical effect of bone cement-strengthened pedicle screw technique in the correction of stage Ⅲ asymptomatic Kümmell disease with kyphosis. METHODS: A retrospective analysis was conducted on clinical data of 40 asymptomatic stage Ⅲ Kümmell disease patients admitted between March 2019 and December 2021, including 15 males and 25 females, aged from 61 to 81 years old with an average of (67.4±5.2) years old;according to different surgical methods, they were divided into percutaneous kyphoplasty group (PKP) and reinforced screw group. There were 18 patients in PKP group, including 7 males and 11 females, aged from 61 to 78 years old with an average of (66.2±5.5) years old;the courses of disease ranged from 5 to 12 months with an average of (7.33±1.78) months;bone mineral density(BMD) T values ranged from -2.45 to -4.00 with an average of (-3.08±0.46);2 patients with T₈-T₉, 10 patients with T₁₀-T₁₂, and 6 patients with L₁-L₂;treated with PKP. There were 22 patients in reinforced screw group, including 8 males and 14 females, aged from 65 to 81 years old with an average of (68.5±3.8) years old;the courses of disease ranged from 4 to 15 months with an average of (7.86±2.73)months;bone mineral density(BMD) T values ranged from -2.40 to -4.50 with an average of (-3.18±0.54);3 patients with T₈-T₉, 12 patients with T₁₀-T₁₂, and 7 patients with L₁-L₂;treated with bone cement reinforced pedicle screw internal fixation combined with kyphoplasty. Cobb angle and anterior margin height of the injured vertebra were compared before operation, 3 d and 12 months after operation. Visual analogue scale (VAS) and Oswestry disability index (ODI) were compared between two groups before operation and 12 months after operation. The incidence of postoperative complications was compared between two groups. RESULTS: All patients were followed up, PKP group followed up for 11 to 14 months with an average of (11.97±0.96) months and 10 to 14 months with an average of (12.05±1.09) months in reinforced screw group;there was no significant difference between two groups (P>0.05). Postoperative Cobb angle at 3 days and 12 months in reinforced screw group were (7.34±2.26) ° and (18.86±1.96) °, while in PKP group were (18.88±1.89) ° and (23.28±1.90) °;there were statistical difference between two groups (P<0.05). The anterior margin height of the injured vertebra in reinforced screw group were (25.28±1.33) mm and (19.62±2.22) mm at 3 days and 12 months after operation, while in PKP group were (18.61±2.16) mm and(15.93±1.34) mm;there were statistical difference between two groups (P<0.05). Cobb angle and the anterior margin height of the injured vertebra were significantly improved at 3 days and 12 months after operation between two groups (P<0.05). Postoperative VAS and ODI at 12 months in PKP group were (2.00±0.69) score and (13.44±4.02)%, while in reinforced screw group were(1.91±0.61) score and (10.18±4.26)%;which were significantly lower than (6.89±0.76) score and (36.33±3.40)% in PKP group, (7.23±0.75) score and (37.09±3.73) % in reinforced screw group before operation. There were no difference in postoperative VAS between two groups at 12 months (P>0.05);postoperative ODI in reinforced screw group at 12 months was lower than that in PKP group(P<0.05). There was no significant difference in complications between two groups (χ²=0.071, P>0.05). CONCLUSION PKP and bone cement reinforced nail combined with PKP could improve kyphotic deformity and postoperative function, and relieve pain. The application of bone cement-reinforced nail fixation technology could provide a more stable support, more obvious functional recovery, lower the risk of re-collapse of the injured vertebra, and maintain the long-term stability of spine.
Humans ; Male ; Female ; Aged, 80 and over ; Kyphosis/surgery* ; Aged ; Bone Cements ; Middle Aged ; Retrospective Studies ; Pedicle Screws ; Spinal Fractures/surgery* ; Fracture Fixation, Internal/methods* ; Bone Screws ; Kyphoplasty

OBJECTIVE: To evaluate the dynamic changes of glucocorticoid (GC) dose and the feasibility of GC discontinuation in rheumatoid arthritis (RA) patients under the background of Chinese medicine (CM). METHODS: This multicenter retrospective cohort study included 1,196 RA patients enrolled in the China Rheumatoid Arthritis Registry of Patients with Chinese Medicine (CERTAIN) from September 1, 2019 to December 4, 2023, who initiated GC therapy. Participants were divided into the Western medicine (WM) and integrative medicine (IM, combination of CM and WM) groups based on medication regimen. Follow-up was performed at least every 3 months to assess dynamic changes in GC dose. Changes in GC dose were analyzed by generalized estimator equation, the probability of GC discontinuation was assessed using Kaplan-Meier curve, and predictors of GC discontinuation were analyzed by Cox regression. Patients with <12 months of follow-up were excluded for the sensitivity analysis. RESULTS: Among 1,196 patients (85.4% female; median age 56.4 years), 880 (73.6%) received IM. Over a median 12-month follow-up, 34.3% (410 cases) discontinued GC, with significantly higher rates in the IM group (40.8% vs. 16.1% in WM; P<0.05). GC dose declined progressively, with IM patients demonstrating faster reductions (median 3.75 mg vs. 5.00 mg in WM at 12 months; P<0.05). Multivariate Cox analysis identified age <60 years [P<0.001, hazard ratios (HR)=2.142, 95% confidence interval (CI): 1.523-3.012], IM therapy (P=0.001, HR=2.175, 95% CI: 1.369-3.456), baseline GC dose ⩽7.5 mg (P=0.003, HR=1.637, 95% CI: 1.177-2.275), and absence of non-steroidal anti-inflammatory drugs use (P=0.001, HR=2.546, 95% CI: 1.432-4.527) as significant predictors of GC discontinuation. Sensitivity analysis (545 cases) confirmed these findings. CONCLUSIONS RA patients receiving CM face difficulties in following guideline-recommended GC discontinuation protocols. IM can promote GC discontinuation and is a promising strategy to reduce GC dependency in RA management. (Trial registration: ClinicalTrials.gov, No. NCT05219214).
Adult ; Aged ; Female ; Humans ; Male ; Middle Aged ; Arthritis, Rheumatoid/drug therapy* ; Glucocorticoids/therapeutic use* ; Medicine, Chinese Traditional ; Retrospective Studies

A novel series of 2-aryl substituted benzothiopyranone compounds was designed and synthesized based on our previously obtained benzothiopyranone scaffold with significant antituberculosis activity. All target compounds were evaluated for their antimycobacterial activity and preliminary druggability was subsequently investigated for some selected compounds with good activity. The results indicated that most compounds showed good activity against Mycobacterium tuberculosis H₃₇Rv. Among them, compounds 8g, 8h, 8q and 9f showed potent activity with MIC ranged from 0.2 to 0.4 μg·mL^-1. Furthermore, some active compounds exhibited low cytotoxicity and cardiotoxicity risk. It is worth noting that compounds 8h and 8q with good liver microsome stability and low inhibition of CYPs 3A4/5 and 2C9 were suitable for combination drug regimen to treat tuberculosis.

The assessment of adverse drug events is an important basis for clinical safety evaluation and post-marketing risk control of drugs,and its causality assessment is gaining increasing attention.The existing methods for assessing the causal relationship between drugs and the occurrence of adverse reactions can be broadly classified into three categories:global introspective methods,standardized methods,and probabilistic methods.At present,there is no systematic introduction of the operational details of the various methods in the domestic literature.This paper compares representative causality assessment methods in terms of definition and concept,methodological steps,industry evaluation and advantages and disadvantages,clarifies the basic process of determining the causality of adverse drug reactions,and discusses how to further improve the adverse drug reaction monitoring and evaluation system,with a view to providing a reference for drug development and pharmacovigilance work in China.

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]

Aim To investigate the mechanisms of Chaijin JieYu Anshen formula modulating the depres-sive behaviors and the synaptic plasticity of hippocam-pal neurons in insomnia-concomitant depression rats based on the histone deacetylase 5(HDAC5)/myocyte enhancer factor 2C(MEF2C)pathway.Methods A rat model of insomnia-concomitant depression was es-tablished by PCPA injection combined with chronic un-predictable mild stress(CUMS),and the experiment was divided into the control group,the model group,the high,medium and low dose group of Chaijin JieYu Anshen formula,and the positive drug group.The de-pression of rats was evaluated by sugar-water prefer-ence test,open field test and morris water maze.The levels of 5-hydroxytryptamine(5-HT)and dopamine(DA)in serum were measured by enzyme linked im-munosorbent assay(ELISA).The pathological damage of hippocampal neurons was observed by HE staining and Nissl staining.The damage of dendritic spines of hippocampal neurons was observed by Golgi staining,and the levels of HDAC5,MEF2C,postsynaptic densi-ty-95(PSD-95)and synaptophysin 1(SYN1)in hip-pocampus were measured by Western blot,immunohis-tochemistry and immunofluorescence.Results Com-pared with the model group,the Chaijin JieYu Anshen formula could increase the sugar-water preference rate of the model rats,reduce the immobility time in the open field experiment,increase the total activity dis-tance,shorten the evasion latency in the localization navigation experiment,and prolong the residence time in the quadrant where the platform was located in the space exploration experiment(P＜0.05,P＜0.01).Moreover,the Chaijin JieYu Anshen formula improved the hippocampal neuron and dendritic spine damage and increase the dendritic branch length and dendritic spine density of hippocampal neurons(P＜0.01,P＜0.01),restore the serum levels of 5-HT and DA in insomnia-concomitant depression rats(P＜0.05,P＜0.01),down-regulate the HDAC5 protein,and up-regulate the expression of MEF2C,PSD-95,and SYN1 protein(P＜0.05,P＜0.01 or P＜0.001).Conclusions Chaijin JieYu Anshen formula may alle-viate the depression-like behavior of model rats by re-ducing the expression of HDAC5 protein,thus deregu-lating the inhibition of transcription factor MEF2C,promoting the expression of PSD-95 and SNY1 protein,and exerting a protective effect on hippocampal neurons and synapses.

Aim To explore the antimicrobial activity of a novel R-type phage tail-like bacteriocin(PTLB)secreted by Enterobacter cloacae SHAMU191747 a-gainst methicillin-resistant Staphylococcus aureus(MR-SA).Methods Antagonistic activity of E.cloacae SHAMU191747 against MRS A was detected by LB agar plate antagonistic test and LB broth micro-fermentation test.The crude extract of fermentation supernatant of E.cloacae SHAMU191747 was prepared by ultra-high-speed centrifugation and density gradient centrifuga-tion.The novel R-type PTLB in the crude extract was detected by transmission electron microscopy.The an-timicrobial activity of the crude extract against MRSA was verified by LB agar plate spot-seeding method.The molecular weight of the novel R-type PTLB was detected by SDS-PAGE electrophoresis.Results E.cloacae SHAMU191747 secreted a novel R-type PTLB,and had a strong antagonistic effect on MRSA.The no-vel R-type PTLB had a molecular weight of approxi-mately 35 ku and could efficiently kill MRSA.The physical dimensions of its tail-sheath-uncontracted functional molecules were(142.7±4.3)×(13.8±0.6)nm,and those of the tail-sheath-contracted non-functional molecules were(57.7±1.2)×(20.8±1.5)nm.Conclusions The novel R-type PTLB pro-duced by E.cloacae SHAMU191747 can efficiently kill MRSA,and has the potential to be developed into a novel antimicrobial drug with great prospects for clini-cal application.