Objective To evaluate antimicrobial activity of fosfomycin combined with tigecycline against Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae and study the mechanism of drug resistance to fosfomycin. Methods Broth microdilution method was used to independently determine the minimum inhibitory concentrations (MIC)of fosfomycin and tigecycline against 42 Klebsiella pneumoniae isolates (including 20 KPC-producing and 22 KPC non-producing isolates).Checkerboard design method was applied to evaluate combined effect of different concentrations on antimicrobial susceptibility and calculate the fractional inhibitory concentration index (FICI).FICI=MICfosfomycin joint/MICfosfomycin monotherapy +MICtigecycline joint/MICtigecycline monotherapy .Related interpretation criteria were as following:FICI≤0.5 means synergy;0.5 2 means antagonism.The fosfomycin resistant genes in KPC-producing Klebsiella pneumoniae isolates were screened.The data were analyzed by t test.Results Antimicrobial susceptibility testing results indicated the fosfomycin and tigecycline susceptibility rates in KPC-producing isolates were 35 .0%(7/20)and 70.0% (14/20 ),respectively.The susceptibility rates of drug combination increased to 50.0% (10/20 )and 95 .0% (19/20 ),respectively,with both MIC decreased.MIC of tigecycline decreased significantly after combination therapy and showed a statistical significance compared with the MIC of monotherapy (t = - 2.596,P = 0.013 ),whereas there was no significant difference between single and combined therapy of fosfomycin (t=-1 .274,P =0.211).FICI indicated that a total of 60.0%isolates showed synergy and additive effects between two antimicrobial agents,followed by indifference (40.0%),but there was no antagonism effect.Among 22 KPC non-producing isolates,there were 54.5 %showing indifference effects,followed by additive (31 .8%)and synergy (13.6%)effects.No antagonism effect was found.The study also identified two isolates with fosA resistant gene which located on the same plasmid as well as the bla KPC gene.The plasmid sizes in the two isolates were 138.9 kb and 104.5 kb, respectively.Conclusions KPC-producing Klebsiella pneumoniae are more susceptible to tigecycline. Combined use of two antimicrobial agents mainly exerts synergy and additive effect rather than antagonism,which may suggest the combination therapy strategy could inhibit the activity of KPC-producing Klebsiella pneumoniae .

Objective To analyze the colistin heteroresistance in Pseudomonas aeruginosa strains and their in vitro susceptibility to antibiotics used in combination.Methods Two hundred and ninety-seven carbapenem-resistant Pseudomonas aeruginosa strains were selected for this study.Broth microdilution method was used to determine the minimum inhibitory concentrations of colistin and other antimicrobials against the Pseudomonas aeruginosa strains.The colistin heterogeneity of 20 colistin sensitive strains was analyzed by using population analysis profiles.The time-kill curves of 3 randomly selected colistin heteroresistant strains were used to determine the bacteriostatic activity of colistin.Chequer-board method was used to measure the combination efficacy of colistin with other antimicrobials including imipenem,meropenem,biapenem,ceftazidime,levofloxcin,piperacillin/tazobactam and cefoperazone/sulbactam.Results The colistin sensitive Pseudomonas aeruginosa strains accounted for 99.66％ of the 297 isolates.Population analysis profiles displayed that 35％ of the 20 isolates were colistin heteroresistant and 20％ of the 20 isolates were heterogeneous.It showed that when colistin was used in combination with other drugs,they mainly had synergistic and additive effects on heteroresistant isolates,but additive and indifferent effects on non-heterogeneous isolates.Conclusion Multidrug resistant Pseudomonas aeruginosa strains were highly susceptible to colistin,but heteroresistant and heterogeneous strains were common.The efficacy of colistin against heteroresistant isolates could be enhanced by using in combination with other drugs.

ObjectiveTo investigate the potential mechanism of action of the Qufeng Tongqiao Cough-relieving Decoction （祛风通窍止咳方， QTCD） in the treatment of upper airway cough syndrome （UACS）. MethodsTwenty-four guinea pigs were randomly divided into blank group， model group， traditional Chinese medicine （TCM） group， and inhibitor group， with six guinea pigs in each group. Except for the blank group， guinea pigs were sensitized with ovalbumin and aluminum hydroxide via intraperitoneal injection， followed by ovalbumin nasal drops combined with smoke exposure to establish the UACS model. After modeling， the TCM group was administered QTCD 0.9 g/（100 g·d） by gavage， the inhibitor group received the transient receptor potential vanilloid receptor 4 （TRPV4） inhibitor GSK2193874 1 mmol/L， 5 min by nebulisation， and the blank group and model group were given 2 ml/（100 g·d） normal saline by gavage once daily. After 7 days of treatment， a cough provocation test was performed using 0.4 mol/L citric acid. The levels of IgE in serum and inflammatory cytokines， including interleukin-6 （IL-6）， interleukin-8 （IL-8） in serum， bronchoalveolar lavage fluid （BALF）， and nasal lavage fluid （NLF） were detected by enzyme-linked immunosorbent assay （ELISA）. Histopathological changes in lung and nasal mucosal tissues were observed by hematoxylin-eosin （HE） staining. Immunohistochemistry was used to detect the protein levels of TRPV4， substance P （SP）， and calcitonin gene-related peptide （CGRP） in lung and nasal mucosal tissues. Real-time polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of TRPV4， SP， and CGRP in lung tissues. ResultsHE staining showed significant structural damage and infiltration of inflammatory cells in the lung and nasal mucosal tissues in the model group， while the TCM group and inhibitor group showed improved pathological changes. Compared with the blank group， the model group showed increased cough frequency， serum IgE level， and IL-6 and IL-8 levels in serum， BALF， and NLF. The protein levels of TRPV4， SP， and CGRP in lung and nasal mucosal tissues and their mRNA expression were elevated （P＜0.05 or P＜0.01）. Compared with the model group， the TCM group and inhibitor group showed reduced cough frequency， serum IgE level， and TRPV4 and SP mRNA expression in lung tissues. The TCM group showed reduced IL-6 and IL-8 levels in serum， BALF， and NLF， and reduced TRPV4 and CGRP protein levels in lung and nasal mucosal tissues. The inhibitor group showed reduced IL-6 and IL-8 levels in serum， BALF， and NLF， reduced IL-6 in BALF， reduced IL-8 in NLF， and decreased TRPV4， SP， and CGRP protein levels in lung tissues and SP and CGRP protein levels in nasal mucosal tissues （P＜0.05 or P＜0.01）. Compared with the TCM group， the inhibitor group had increased serum IgE， IL-6， and IL-8 levels， increased IL-6 level in BALF， and increased IL-8 levle in NLF， but decreased SP protein level in lung tissues and increased TRPV4 and SP mRNA expression in lung tissues （P＜0.01）. ConclusionQTCD effectively reduces cough frequency in the UACS guinea pig model. Its mechanism may involve inhibiting the activation of the TRPV4 pathway， improving airway neurogenic inflammation， alleviating inflammatory responses， and reducing cough hypersensitivity.

Objective: To understand the consistency of ALK Ventana-D5F3 immunohistochemistry (IHC) interpretation in Chinese lung adenocarcinoma among histopathologists from different hospitals, and to recommend solution for the problems found during the interpretation of ALK IHC in real world, with the aim of the precise selection of patients who can benefit from ALK targeted therapy. Methods: This was a multicenter and retrospective study. A total of 109 lung adenocarcinoma cases with ALK Ventana-D5F3 IHC staining were collected from 31 lung cancer centers in RATICAL research group from January to June in 2018. All cases were scanned into digital imaging with Ventana iSCANcoreo Digital Slide Scanning System and scored by 31 histopathologists from different centers according to ALK binary (positive or negative) interpretation based on its manufacturer′s protocol. The cases with high inconsistency rate were further analyzed using FISH/RT-PCR/NGS. Results: There were 49 ALK positive cases and 60 ALK negative cases, confirmed by re-evaluation by the specialist panel. Two cases (No. 2302 and No.2701) scored as positive by local hospitals were rescored as negative, and were confirmed to be negative by RT-PCR/FISH/NGS. The false interpretation rate of these two cases was 58.1% (18/31) and 48.4% (15/31), respectively. Six out of 31 (19.4%) pathologists got 100% accuracy. The minimum consistency between every two pathologists was 75.8%.At least one pathologist gave negative judgement (false negative) or positive judgement (false positive) in the 49 positive or 60 negative cases, accounted for 26.5% (13/49), 41.7% (25/60), respectively, with at least one uncertainty interpretation accounted for 31.2% (34/109). Conclusion There are certain heterogeneities and misclassifications in the real world interpretation of ALK-D5F3 IHC test, which need to be guided by the oncoming expert consensus based on the real world data.