Zhejiang University, Professor Yu Yunsong research team and its leadership of the National Network of clinical and microbial collaboration, through the mcr-1 gene carrying the plasmid bioinformatics analysis, clear mcr-1 gene transmission mechanism, the clinical data show that mcr-1 positive strains are not On the prognosis of infected patients. The results of the study were: "Prevalence of mcr-1 in Escherichia coli and Klebsiella pneumoniae recovered from blood stream infections in China: a multicentre longitudinal study" (Chinese bloodstream infection Escherichia coli and Klebsiella pneumoniae mcr-1 gene prevalence: Multi-center longitudinal study) was published online January 27, 2017 in the world famous medical journal The Lancet Infectious Diseases published online.
In recent years, the phenomenon of bacterial resistance is increasingly serious, to the anti-infective treatment has brought major challenges, a serious threat to human health, has become an important public health problem. Polymyxin is considered to be the last line of defense for the treatment of multidrug-resistant Gram-negative bacteria, which has not yet been approved for clinical use in China. As early as the 20th century, 80 years polymyxin has been widely used in animal breeding industry, our scholars in 2015 first found the plasmid-mediated polymyxin-resistant gene mcr-1, mcr-1 gene in animal gut Escherichia coli in the carrying rate is very high, and spread between animals and humans.
In order to clarify the distribution of mcr-1 gene in the isolates of clinical infection in China, the level of polymyxin resistance, the molecular epidemiological characteristics of mcr-1 plasmid and its effect on the choice and prognosis of infected patients. The research team conducted a large-scale, large sample of clinical infection cases from 2066 strains of clinically important types of infection - bloodstream infection pathogens Escherichia coli and Klebsiella pneumoniae in the screening of polymyxin-resistant strains And mcr-1 gene positive strains. A total of 21 mcr-1 positive strains were obtained. The study team used conventional bacteriological susceptibility test, molecular typing, clinical data statistical analysis and other means, and through imprinting hybridization and three generations of sequencing technology, mcr-1 gene distribution, gene mapping, transmission mechanism and clinical prognosis Conducted a systematic study.
The results showed that the isolated isolates of Escherichia coli and Klebsiella pneumoniae isolated from patients with clinical bloodstream infection were less distributed. The rate of polymyxin in patients was 1.3%, among which Escherichia coli was 1.5% and Klebsiella pneumoniae was 0.7%. The detection rate of mcr-1 gene was 1.0% 14% for the bacteria and 0.2% for Klebsiella pneumoniae. Escherichia coli is the main host of the mcr-1 gene. The mcr-1 gene often results in low levels of polymyxin resistance (the minimum inhibitory concentration is predominantly in the range of 4-16 mg / L), and most of the strains carrying the mcr-1 gene are sensitive to many other types of antimicrobial agents The Only one of the five mcr-1 positive strains carried CTX-M extended-spectrum β-lactamase, and one mcr-1 positive strain was carrying the carbapenemase gene blaNDM-5, but not with the mcr-1 gene On a plasmid.
The Lancet Infectious Diseases magazine commented extensively on the results of this study, spoke highly of Yu Yunsong team for the bloodstream infection mcr-1 gene epidemic research significance; and that China is currently worried about carbapenem and polymyxin However, with the use of polymyxin in China, the epidemic, risk factors, clinical prognostic effects The Washington Post, Yahoo News and other foreign mainstream media are also competing to report the results of the study.
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