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Objective:To investigate the diagnostic value of metagenomic next-generation sequencing (mNGS) in AIDS patients complicated with Pneumocystis jirovecii ( P. jirovecii) infection. Methods:This is a retrospective study. From January 2019 to June 2021, the respiratory tract and other body fluid samples of 236 cases of AIDS co-infected patients diagnosed in the AIDS Department of Changsha First Hospital were collected, along with corresponding medical histories. Traditional etiological hexamine silver staining and serum 1,3-β-D glucan (BDG) were performed simultaneously with mNGS detection, and Fisher′s exact test was used to analyze the results and compare the diagnostic performances of mNGS with those of hexamine silver staining and serum G test.Results:A total of 236 cases of AIDS patients with pulmonary infection were collected and tested. Seventy-seven cases were clinically diagnosed with Pneumocystis jiroveci pneumonia and 159 cases with non- Pneumocystis jiroveci pneumonia. Among the 236 AIDS patients with pulmonary infection, mNGS detected 77 [32.63%(77/236)] positive cases of Pneumocystis jiroveci, while hexamine silver staining detected 10[4.24%(10/236)] and serum BDG detected 146 [61.86% (146/236). Based on these clinical diagnostic results, the sensitivity of mNGS detection was 100% (77/77) for the 77 patients with Pneumocystis pneumoniae, significantly higher than that of silver hexamine staining [12.99% (10/77), P=0.046] and serum BDG [58.44% (45/77), P=0.038]. The mNGS showed good specificity, which was the same as that of hexamine silver staining [100% (159/159)] and significantly higher than that of serum BDG [36.48% (58/159), P=0.026]. With therapeutic clinical diagnosis as the reference method, the accuracy of mNGS detection was 100% (236/236). Conclusions:This study evaluated the diagnostic value of mNGS detection in AIDS patients with Pneumocystis jirovecii infection. The results showed that the sensitivity and specificity of mNGS detection were high, and it had exceptional clinical application value in the pathogenic detection of infectious diseases.
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Objective To investigate the genotypes and epidemic of metallo-β-lactamase-(MBL )-producing Pseudomonas aeruginosa (P .aeruginosa)in Changsha.Methods P .aeruginosa isolated from seven comprehensive hospitals in Changsha were collected and performed identification and antimicrobial susceptibility testing,pheno-types of MBL were detected with EDTA-disk synergy test and E-test,genotypes were determined by polymerase chain reaction (PCR),homology analysis were conducted by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR).Results Preliminary screening by EDTA-disk synergy test and E-test showed that only 10 of 81 iso-lates were strong positive;PCR result showed that 18 isolates were positive for MBL,11 of which were IMP-9-type MBL,1 was IMP-1-type,and 6 were VIM-2-type.SIM,SPM,GIM,and NDM-1-types were not found.ERIC-PCR showed that 12 strains of IMP-producing P .aeruginosa has multiple types,6 VIM-2-producing strains were of the same type.Conclusion IMP-9 and VIM-2 are main genotypes in P .aeruginosa in Changsha.
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OBJECTIVE@#To survey antibiotic resistance of clinical isolates of Acinetobacter baumannii in Changsha and to investigate molecular epidemiological characteristics of carbapenem-resistant Acinetobacter baumannii.@*METHODS@#A total of 205 non-duplicated, clinical isolates of Acinetabacter baumannii from 10 general hospitals in Changsha were collected from March 2010 to December 2010. The K-B disk diffusion method was applied for the drug-susceptibility test; a modified, double-disk synergy test was used to detect metallo-β-lactamase (MBL), and a modified Hodge test was used for the screening of carbapenemase. PCR was used to amplify carbapenemase genes (including OXA-23, OXA-24, OXA-51, IMP-1, and VIM-2) and the positive products were sequenced. Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) was used for DNA typing and test of homology.@*RESULTS@#Of the 18 antibiotics tested, 14 had a high rate of resistance (>50% of the isolates tested), with piperacillin the highest (80.5% of strains), and cefoperazone/sulbactam the lowest (2.5%). In total, 115 carbapenem-resistant Acinetobacter baumannii strains were confirmed, but their MBL phenotype and genes were all negative. Seventy-one positive strains were detected by the modified Hodge test, among which 64 strains were OXA-23-positive. All the 115 strains were positive for the amplification of the OXA-51 gene, and no strain was found which carried OXA-24 or OXA-58 gene. Seven genomic types were included in the 115 Acinetobacter baumannii. The major prevalence types were Type B ( 72 strains) and Type A (19 strains).@*CONCLUSION@#Multiple drug resistance of clinically isolated Acinetobacter baumannii is a serious problem in Changsha. Production of OXA-23 and OXA-51 carbapenemases is an important mechanism of resistance to carbapenem antibiotics, and there is prevalence of the same clones in these carbapenem-resistant strains.