ABSTRACT
Objective:To evaluate the diagnostic value of metagenomics next-generation sequencing (mNGS) in detecting pathogens in bronchoalveolar lavage fluid (BALF) for pulmonary infection in solid organ transplant patients in intensive care unit (ICU).Methods:A retrospective study was conducted, the BALF samples from 46 patients with post organ transplant pneumonia/suspected pneumonia admitted to the Department of Critical Care Medicine of the First Affiliated Hospital of University of Science and Technology of China from August 2018 to August 2021 were collected, all tested by simultaneous mNGS and conventional comprehensive microbial test (CMT), and the results of CMT were used as the reference standard to compare the differences in the diagnostic value of mNGS and CMT for pulmonary infections in solid organ transplant patients, and to analyze the diagnostic value of mNGS for mixed infections.Results:① Pneumonia pathogens: a total of 31 pathogens were detected in 35 patients, including bacteria (16 species), fungi (9 species) and viruses (6 species). Among them, 25 pathogens were detected by mNGS and CMT, and only 19 pathogens were detected by mNGS. Among the microorganisms isolated by mNGS method, the detection rates of Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae were higher [51.4%(18/35), 42.9% (15/35), 31.4% (11/35), respectively]; Candida albicans, Aspergillus and Pneumocystis carinii were the most commonly detected fungi [31.4% (11/35), 22.9% (8/35), 22.9% (8/35), respectively]; 20 patients were positive for the virus, and the most commonly detected viruses were cytomegalovirus, herpesvirus and EB virus [28.6% (10/35), 20.0% (7/35), 17.1% (6/35), respectively]. In addition, one case of Brucella was detected by mNGS.② Diagnostic efficiency: as far as bacterial detection is concerned, 20 cases of negative results were obtained by CMT detection of 35 samples included in the study, and a total of 10 cases of positive results were obtained by mNGS detection of negative samples; the percentage of mNGS positive samples was significantly higher than that of CMT positive samples [odds ratio ( OR) = 5.5, 95% confidence interval (95% CI) = 1.2-24.8, P = 0.02]. When compared with CMT, the sensitivity and specificity of mNGS were 93.3% and 50.0%, and the positive predictive value (PPV) and negative predictive value (NPV) were 58.3%, 91.1%. As far as fungal detection was concerned, there was no significant difference in the percentage of positive samples between the two methods ( OR = 1.5, 95% CI = 0.5-4.2, P = 0.60); the sensitivity and specificity of mNGS were 72.2% and 64.7%, and the PPV and NPV were 68.4%, 68.8%; CMT test of the 35 included samples produced 17 negative results, and mNGS test of the negative samples produced 6 positive results. A total of 20 patients tested positive for the virus by mNGS. In addition, 23 patients (65.7%) were diagnosed with pulmonary mixed infection. Conclusion:The use of mNGS to detect pathogens in BALF can improve the sensitivity and specificity of bacterial identification of pulmonary infection in critically ill organ transplant patients, and mNGS has obvious advantages in detecting virus and identifying mixed infections.
ABSTRACT
Objective To observe the effects of perfusion of rosiglitazone (RSG) in lesion areas on the expression levels of the perihematomal tight junction-associated proteins occludin and zonula occluden-1 (ZO-1) mRNA,the permeability of blood-brain-barrier (BBB),and neurological function score in a rabbit model of cerebral hemorrhage (ICH).Methods A total of 45 healthy male rabbits were selected (a body mass of 2.0 to 2.5 kg).They were divided into 3 groups,a control group,a ICH model group,and a RSG treatment group (n =15,5 of them for BBB determination) according to the random number table.The control group was use to simulate the process of making intracranial hematoma.After successful puncture,the target was iujected with isotonic saline 0.3 ml and isotonic saline 0.1 ml was injected again after 6 h;after successful puncture,the ICH model group was injected with 0.3 ml of autologous non-anticoagulant arterial blood,and the target was injected into isotonic saline 0.1 ml after 6 h;RSG 0.5 mg was infused into the hematoma area (dissolved in 0.1 ml isotonic saline) in the RSG treatment group at 6 h after the ICH model was successfully induced.All rabbits in each group were sacrificed on day 7 after the neurological deficit scale score (Purdy score).Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression levels of perihematomal oecludin and ZO-1 mRNA.The formamide method was used to measure the Evans blue (EB) content in the perihematomal tissue in order to evaluate the permeability of BBB.Results (1) Neurological function scores:Purdy scores of the control group,ICH model group,and RSG treatment group were 2.53 ± 0.05,8.13 ± 0.06),and 6.67 ± 0.08,respectively.There were significant differences among the groups (F =459.116,P ＜ 0.01).Compared with the control group,Purdy scores of the ICH model group and RSG treatment group were increased significantly (all P ＜ 0.01).Compared with the ICH model group,Purdy scores of the RSG treatment group were decreased (P ＜ 0.05).(2) The expression levels of occludin and ZO-1 mRNA:The differences were statistically significant in occludin and ZO-1 mRNA in the control group,ICH model group,and RSG treatment group (1.013 ±0.051,1.001 ± 0.045;0.221 ± 0.017,0.247 ± 0.019;0.498 ± 0.041,and 0.613 ± 0.045,respectively in each group;F =443.924 and 381.929 respectively,all P ＜ 0.01).Compared with the control group,the expression levels of occludin and ZO-1 mRNA were significantly decreased in the ICH model group and RSG treatment group (all P ＜ 0.01).Compared with the ICH model group,the expression levels of occludin and ZO-1 mRNA were increased in the RSG treatment group (all P ＜ 0.05).(3) The permeability of BBB:The EB content in the control group,ICH model group,and RSG treatment group were 12.0 ± 1.0,51.6 ± 0.9,and 36.4 ± 1.0 μg/g,respectively.The differences were statistically significant among the groups (F =223.516,P ＜ 0.01).Compared with the control group,the EB content was significantly increased in the ICH model group and RSG treatment group (all P ＜ 0.01).Compared with the model group,the EB content was significantly decreased in the RSG treatment group (P ＜ 0.01).Conclusion The perfusion of RSG in the lesion area can significantly improve the neurological function of rabbits after ICH,increase the expression levels of occludin and ZO-1 mRNA in the perihematomal tissue,and decrease the permeability of BBB.