Application of 16s rDNA Sequencing in the Analysis of Pathogenic Bacteria in Sputum of Severe Bacterial Pneumonia

Objective: 120 patients with severe pneumonia who were kept in the comprehensive ICU of our hospital in 2018 were selected, and 16s rDNA sequencing was performed to analyze the composition of pathogenic bacteria in the sputum of severe pneumonia. Methods: The sputum samples of patients with severe bacterial pneumonia were collected, and the diversity of pathogens in the samples was analyzed by polymerase chain reaction (PCR) amplification and high-throughput sequencing (16s rDNA PCR-DGGE). Results: Sequence showed that sputum samples contained a relatively large number of species, and there were many species that were not detected by sequencing. The dominant bacteria were Streptococcus, Sphingomonas, Corynebacterium, Denatobacteria, Aquobacteria, Acinetobacteria, Prevotella, Klebsiella, Pseudomonas, etc. Conclusion: Bacteria caused by sputum of severe bacterial pneumonia are complex and diverse, which provides new methods and ideas for individualized treatment of patients with severe pneumonia.

Application of 16S rDNA Sequencing Technology in the Analysis of Pathogenic Bacteria in Sputum of Severe Pneumonia

The diagnosis of pathogenic bacteria in severe pneumonia is difficult and the prognosis is poor. Its outcome is closely related to bacterial pathogenicity and the timeliness and pertinence of antibiotic treatment. Therefore, early diagnosis is of great significance to the prognosis of patients. Sputum examination and culture is the gold standard for the diagnosis of pathogens of severe pneumonia. However, due to the long time of bacterial culture, the early use of antibiotics, the change of bacteria species, mixed infection and other problems, the results of bacterial culture in sputum are often false negative. With the continuous application of new molecular biology techniques in clinical detection, the classification of bacteria and microorganisms has deepened from the identification of phenotypic characteristics to the classification of gene characteristics. Sequencing analysis with 16S rDNA sequencing technology has the characteristics of high sequencing flux, large amount of data obtained, short cycle, and can more comprehensively reflect the species composition of microbial community, real species distribution and abundance information. In this paper, 16S rDNA sequencing technology was used to analyze the bacterial population composition in the sputum of severe pneumonia, and to explore a new method of etiological diagnosis.

High-performance lung-targeted bio-responsive platform for severe colistin-resistant bacterial pneumonia therapy

Polymyxins are the last line of defense against multidrug-resistant(MDR)Gram-negative bacterial infections.However,this last resort has been threatened by the emergence of superbugs carrying the mobile colistin resistance gene-1(mcr-1).Given the high concentration of matrix metalloproteinase 3(MMP-3)in bacterial pneumonia,limited plasma accumulation of colistin(CST)in the lung,and potential toxicity of ionic silver(Ag+),we designed a feasible clinical transformation platform,an MMP-3 high-performance lung-targeted bio-responsive delivery system,which we named“CST&Ag@CNMS”.This system exhibited excellent lung-targeting ability(>80%in lungs),MMP-3 bio-responsive release property(95%release on demand),and synergistic bactericidal activity in vitro(2-4-fold minimum inhibitory concentration reduction).In the mcr-1+CST-resistant murine pneumonia model,treatment with CST&Ag@CNMS improved survival rates(70%vs.20%),reduced bacteria burden(2-3 log colony-forming unit[CFU]/g tissue),and considerably mitigated inflammatory response.In this study,CST&Ag@CNMS performed better than the combination of free CST and AgNO3.We also demonstrated the superior biosafety and biodegradability of CST&Ag@CNMS both in vitro and in vivo.These findings indicate the clinical translational potential of CST&Ag@CNMS for the treatment of lung infections caused by CST-resistant bacteria carrying mcr-1.